On 8 September, 1978, Bell announced its intention to develop a four-bladed variant of its twin-turbine Model 212. Designated Model 412, this helicopter was the first four-blade rotor helicopter to be produced by Bell. The rotor head had elastomeric bearings that eliminated both mechanical hinges and viscous dampers. In mid-1984, the internal vibration level was further lowered by the introduction of a pendulum damper kit on production aircraft, but this was also available independently for retrofit to earlier machines.
Two newly built Model 212 airframes served as development prototypes and for the certification programme. The Model 412 retained the same powerplant as the Model 212, the Pratt & Whitney Canada PT6-3B-1 Turbo Twin Pac delivering 1400hp for take-off and 1130hp for continuous operation. The blades, fitted with a Nomex honeycomb core, are bonded together by glassfibre wrapping incorporating anti-icing heater mats and are interchangeable. The rotor mast is shorter than the 212, with blades that can be folded ans a rotor brake as standard. The main rotor rpm is 314. Equipped with a two-blade tail rotor. The elastomeric bearings of the hub eliminate both mechanical hinges and heavy, viscous dampers. This improves the ride and also extends the rotor system life, while the flex beam yoke of the main rotor hub provides quick control response. The new bearings require no lubrication and require only a quick visual inspection to confirm integrity. In the drive system, five of the six-rotor drive shaft sections are interchangeable, reducing spares. Main transmission chip detectors help protect the system. The four composite blades have an unlimited life and span wise variation of their chord, twist and thickness of airfoils give added turning and aerodynamic efficiency. Generally of conventional light metal. Main rotor blade spar unidirectional glass libre with 45degree wound torque casing of glass fibre cloth; Nomex rear section core with trailing-edge of unidirectional glass fibre; leading-edge protected by titanium abrasion strip and replaceable stainless steel cap at tip; lightning protection mesh embedded; provision for electric de-icing heater elements; main rotor hub of steel and light alloy; all-metal tail rotor. The undercarriage is high skid, emergency pop-out float or non-retractable tricycle gear optional. Spats optional. Fuel in in seven interconnected rupture-resistant fuel cells, with automatic shutoff valves (breakaway fittings), have a combined usable capacity of 1,249 litres. Two 76 or 310.5 litre auxiliary fuel tanks, many combination, can increase maximum total capacity to 1.870 litres. Single-point refuelling on starboard side of cabin. The cabin hold a pilot and up to 14 passengers: one in front port seat and 13 in cabin. Dual controls optional. Accommodation heated and ventilated. The first modified helicopter made its maiden flight in early August 1979, followed by the second machine in December of the same year. FAA Pt 29 type approval was given on 9 January, 1981, and IFR certification came on 13 February, 1981. The first deliveries had taken place on 18 January, 1981, ERA Helicopter Inc of Anchorage received its first aircraft (c/n 33001, N412EH), this company eventually acquiring up to nine Model 412s (c/n 33004/N164EH, 33007/ N414EH, 33009/N415EH, 33011/ N416EH, 33043/N419EH, 33068/ N422EH, 33069/N524EH and 33072/N356EH) to be operated alongside some sixteen Model 212s and fifty-two other Bell helicopters. Two were delivered to the Venezuelan Air Force later in the year. By the end of 1987, a total of 145 Model 412s had been delivered. 213 were built in USA before production (SP version) was transferred to Canada in February 1989. A majority of the operators are civil. Only a few machines have been sold to military customers: two aircraft to Bahrain Defence Force Air Wing with codes BPS-03 and 04; two to the Venezuelan Air Force (one is c/n 33013); three TO the Botswana Defence Force (with two more on order); one to Panama (c/n 33091, serialled FAP-1101); four to Sri Lanka’s armed forces; two to the Nigerian Police Air Wing; an estimated seven to the Bangladesh Air Force and some aircraft to Peru to equip Escuadron 341 and Escuadrilla Presidencial. An improved variant, the Model 412SP (SP for Special Performance), was later introduced. This Model had increased maximum take-off weight, a 55 per cent increase in fuel capacity and new interior seating options. The 412SP (Special Performance) is powered by Pratt & Whitney PT6T-3B-1 turbo Twin-Pacs developing around 1400shp and has a maximum speed of 260kph and a range of over 650km.This variant was also available in both civil and military configurations. Several military operators have ordered Model 412SPs: Bahrain (the Public Security Flying Wing operates two), Botswana (five aircraft to be supplemented by two more in 1991), Honduras (ten), Nigeria (the Police Air Wing received two aircraft), Sri Lanka (four), Venezuela (two) and Norway (eighteen).
In November 1982, a licence agreement was signed with IPTN for the partial manufacture and complete assembly of more than one hundred Model 412s. The first of these Indonesian-built aircraft (designated NBell-412) flew for the first time in April 1986. Among the customers are the Indonesian armed forces and several private operators. Norway is assembling seventeen out of the eighteen machines ordered in Helikopter Services A/S workshops at Stavanger for the Royal Norwegian Air Force.
Agusta in Italy began production of the Model 412 in 1981, and manufactures the type as the AB 412SP, and has delivered over 75. Agusta and has since developed its own military variant designated AB 412 Griffon. This variant includes a high-energy-absorbing undercarriage, energy attenuating seats and crash resistant self-sealing fuel tanks. Armament can include a wide range of external weapons such as an 12.7mm gun and 25mm Oerlikon cannon under a swivelling turret, four to eight TOW missiles, 70mm rocket launchers, air-to-air missiles and air-to-surface Sea Skua missiles. The Griffon prototype flew for the first time in August 1982 and deliveries began in the following January. Among military customers for the AB 412 are the Italian Army, Carabinieri and Special Civil Protection, Capitanerie di Porto (four AB 412SP for coastal patrol and SAR duties), Dubai Central Military Command (three aircraft), Finnish Coast Guards (two), Ugandan Army and Zimbabwe Air Force (ten). In June 1986 Bell produced the 412 Attack Helicopter (AH) based on the Bell 412SP.
The demonstrator aircraft (c/n 33119, N412AH) was equipped with a 0.50m machine-gun (carrying 875 rounds) in a Lucas Aerospace undernose turret aimed through a Sperry Head Tracker helmet sight system (as on the AH-1S) and had provision for nineteen air-to-ground rockets on each side of the cabin. The 412AH has a maximum speed of 220kph. By January 1989, 162 Model 412s had been delivered. The Bell 412 is operated by the RAF as the Griffin. The Bell 412EP Griffin HT.1 being the training variant. Some 635 Bell 412s of alI versions built in North America by early 2003, including 26 delivered in 1999 and in 2000; 22 in 2001 (including five to El Salvador) and in 2002 (including five to Saudi Arabia). Military deliveries include Venezuelan Air Force (two), Botswana Defence Force (three), Public Security Flying Wing of Bahrain Defence Force (two), Sri Lankan armed forces (four), Nigerian Police Air Wing (two), Mexican government (two VIP transports), South Korean Coast Guard (one), Honduras (10), Royal Norwegian Air Force (19, of which 18 assembled by Helikopter Service, Stavanger, to replace UH-1Bs of 339 Squadron at Bardufoss and 720 Squadron at Rygge). Three 412EPs delivered to Slovenian Territorial Forces in 1995, for border patrol and rescue duties; four ordered by Philippine Air Force late in 1996, comprising two for VVIP transport and two SAR; first of nine 412EPs entered service in April 1997 as HT. Mk 1s with civilian-operated Defence Helicopter Flying School at RAF Shawbury, UK, within which they constitute No.60 (Reserve) Squadron, RAF; two more ordered in May 2002. together with four HAR. Mk 2s, latter replacing Wessex SAR helicopters of No.84 Squadron at Akrotiri, Cyprus, from April 2003. Four in SAR/utility fit delivered to Venezuelan Navy, 1999. Recent customers include the National Defence Secretariat of Mexico, which took delivery of four in mid-2002; Venezuelan Navy, which ordered four in SAR configuration in early 2002; and Khalifa Airways of Algeria, which took delivery of one 412EP in June 2002. Costs: Bell 412EP, VFR-equipped US$4,895 million (1999); Bell 412EP, lFR-equipped US$5.12 million (1999).
412SP Special Performance version with increased maximum T-O weight, new seating options and 55% greater standard fuel capacity. Superseded by 412HP early 1991.
Military 412 Announced by Bell June 1986; fitted with Lucas Aerospace chin turret and Honeywell Head Tracker helmet sight similar to that in AH-1S; turret carries 875 rounds, weighs 188kg and can be removed in under 30 minutes; firing arcs 110deg in azimuth, +15deg and –45deg in elevation; other armament includes twin dual FN Herstal 7.62mm gun pods, single FN Herstal 12.7mm pod, pods of seven or nineteen 70mm rockets, M240E1 pintle-mounted door guns, FN Herstal four-round 70mm rocket launcher and a 12.7mm gun or two Giat M621 20mm cannon pods.
412HP Improved transmission giving better OGE hover; FAR Pt 29 certification 5 February 1991, first delivery (c/n 36020) later that month.
412EP (Enhanced Performance) PT6T-3D engine, dual digital automatic flight control system (DDAFCS), three-axis in basic aircraft but customer option for four-axis and EFIS. Category A certification was imminent in late 1998. Also customer option for SAR fit.
412CF (CH-146) Griffon Canadian Forces C$700 million contract for 100 CH-146s (modified Bell 412EP) placed in 1992. Duties include armed support, troop/cargo transport, medevac, ASW, SAR and patrol; first flight (146000) 30 April 1994; deliveries began 14 October 1994; completed early 1998. Generally as commercial Bell 4I2EP except for avionics and mission equipment. Empty weight 3.402kg; maximum weight as civil version.
412EP Sentinel First of two modified in 1998 by Heli-Dyne Systems with quick-change ASV and ASW mission packages; intended for Ecuadorean Navy, but order cancelled and aircraft became demonstrator. ASV equipment comprises Honeywell RDR-1500B chin radar, Hughes Starburst searchlight, radar warning receiver, Wescam sensor turret and possibly Penguin Mk 2 Mod 7 ASMs; ASW fit is L3 Ocean Systems AN/AQS-18A dipping sonar and Raytheon Mk 46 torpedo.
412SA First three of 16 ordered by Royal Saudi Air-Force built in 2001 for manufacturer’s trials. Equipment standard not disclosed, but sufficiently different from 412EP to warrant separate c/n sequence beginning 33501. Production continued in 2002-03.
412 Plus Projected improved version under study in 1999 with MTOW increased to 5.647kg, uprated PT6C engines, new dynamic components and Rogerson-Kratos avionics. Development terminated in early 2001.
NBell-412 Indonesia’s Dirgantara has licence to produce up to 100 Model 412SPs.
AB.412 Griffon Agusta’s multirole military development of the Bell 412 which first flew in August 1982, and is suitable for troop transport, fire-support, scout and reconnaissance, SAR, medevac and maritime surveillance. Armament options include 25mm Oerlikon cannon, machine-gun pods, rocket pods, and Sea Skua ASMs.
Specifications:
412 Engine: 2 x P&W PT6T-3B, 900 shp, 1342kW TBO: 2500 hr Main rotor: 46 ft / 14.02m Seats: 15 Length: 56 ft Length with rotors turning: 17.07m Height: 10.7 ft Max ramp weight: 11,600 lb Max takeoff weight: 11,600 lb Standard empty weight: 6267 lb / 2823kg Max useful load: 5333 lb Max landing weight: 11,600 lb Max sling load: 5000 lb Disc loading: 7 lbs/sq.ft Power loading: 6.4 lbs/hp Max usable fuel: 1455 lb Service ceiling: 20,000 ft Hover in ground effect: 4100 ft Hover out of ground effect: 2000 ft Max speed: 142 kt Normal cruise @ 3000 ft: 125 kt Fuel flow @ normal cruise: 758 pph Endurance @ normal cruise: 1.7 hr
412EP Engine: 1 x P&WC PT6T-3D Twin Pac, 1342kW for T-O / 1193kW max continuous OEI ratings: 850kW for 2 1/2 min / 723kW for 30 min Transmission rating: 1,022kW for T-O, 828kW max continuous OEI rating: 850kW Instant pwr: 1342 kW Rotor dia: 14 m MTOW: 5402 kg Payload: 2319 kg Useful load: 2271 kg Max speed: 140 kt Max cruise: 130 kt Max range: 782 km HIGE (@ MAUW): 10,200 ft HOGE (@MAUW): 5200 ft Service ceiling: 13,100 ft Crew: 1 Seats: 14
412HP Engine: 2 x P&WC PT6T-3BE Instant pwr: 1340 kW Rotor dia: 14 m MTOW: 5400 kg Payload: 2395 kg Useful load: 2395 kg Max speed: 140 kt Max cruise: 130 kt Max range: 745 km HIGE (@MAUW): 10,200 ft HOGE (@MAUW): 5200 ft Service ceiling: 17,000 ft Seats: 15
AB.412 Griffon Engine: 1 x P&WC PT6T-3BE Twin Pac Instant pwr: 764 kW Rotor dia: 14 m Fuselage length: 12.7 m No. Blades: 4 Empty wt: 2840 kg MTOW: 5400 kg Payload: 2290 kg Max speed: 125 kts Max cruise: 122 kts ROC: 440 m/min Ceiling: 5180 m Fuel cap (+aux): 820 lt ( 680 lt ) Range: 480 km Max range: 656 km HIGE: 10,200 m HOGE: 5200 m Crew: 1 Pax: 14
The Bell ARH-70 helicopter was developed for the US Army as a possible direct replacement to the successful but aged Kiowa Warrior series of light armed reconnaissance mounts. In an effort to keep production and acquisition costs down for the US Army, the project attempted to develop a product using existing yet proven components. The Bell ARH was essentially a militarized form of the Bell 407. The ARH-70 came from the US Army’s Armed Reconnaissance Helicopter (ARH) program after the official cancellation of the RAH-66 Comanche light attack helicopter. Initial production forms would have been given the designation of ARH-70A.
In December of 2004, the requirement was sent out by the US Army and interested parties responded with their proposals. Chief among the returns was the Bell Model 407 (billed as an upgraded OH-58 Kiowa Warrior) and a Boeing response. Bell eventually won out and was awarded the multi-billion dollar production contract on July 29th, 2005. The contract called for some 368 production examples and required two prototypes along with two preproduction samples, this later changed to require four pre-production examples instead.
First flight of a demonstrator ARH was achieved on June 3rd, 2005. Further flights ensued and ultimately included additional avionics, mission-specific systems and the selected Honeywell HTS900-2 series turboshaft engine. The engine was trialed only on demonstrators and on the ground to verify its base qualities to this point. After some program delays, the first true ARH-70 prototype (Prototype #2) went airborne on July 20th, 2006, less than one year since the awarding of the Army contract. Prototype #4 was of note for it was forced to make a crash landing at a gold course after suffering an engine failure, this recorded on February 21st, 2007. Though neither of the pilots was harmed in the crash, the airframe was deemed a complete loss and a setback for the ARH program.
Ultimately, delays and product costs soon crept up on the ARH-70. The US Army halted the project, giving Bell one month to get its act in order. For the interim, Bell used its own money to further develop the systems until the US Army agreed to pick up the project once again by the middle of 2007. The rising costs forced an automatic and direct DoD review of the program under the existing Nunn-McCurdy Act. In the 2008 Defense Budget, no money was deviated to furthering the ARH-70. A final attempt to offer the ARH-70 as an export product to help recover some cost fell to naught and the ARH-70 remained in limbo for the time being. At one point, it was expected that some 512 total systems could be purchased by the US military alone, the additional examples over the original agreed upon total being delivered for use by the Army National Guard to replace their aged AH-64 Apaches.
The ARH-70 program proved too much to be a viable option for the US Army, despite the mount reaching all required performance parameters. The Army Acquisition Executive Office for Aviation called for the DoD contract to be terminated in full. The US Department of Defense officially acknowledged the request and did not promote the multi-million dollar expenditure to the US Congress, effectively killing hope for Bell and their new little machine. By this time, a single ARH-70 example had nearly doubled in per-unit cost to an estimated $14.5 million USD. According to Bell, the contract was 53 percent complete at the time of its cancellation on October 16th, 2008, with some 1,500 test flight hours having been recorded.
Design of the ARH-70 followed suit with the OH-58 series family of light helicopters. The two-man crew was seated in a side-by-side arrangement well-forward in the fuselage. Each position featured redundant controls and large, transparent, bulging forward windshields offering excellent visibility. Each pilot maintained their own automobile-style doors, hinged at two points forward, for entry and exit into their respective cockpit seats. Optics and special mission equipment could be mounted externally under the chin portion of the fuselage. The passenger cabin was located directly behind the cockpit and accessed via side access doors. Weapon stub pylons emerged from the fuselage underside and could carry limited offensive munitions. Landing skids were affixed to either fuselage underside and supported at two fixed points. The single engine was fitted high atop the fuselage above and behind the crew cabin. Exhaust jettisoned upwards at the rear of the engine compartment. The engine drove a four-bladed main rotor and a two-bladed tail rotor. The empennage was raised at the rear of the crew cabin and engine compartment, capped by a tall vertical tail fin. Additional vertical fins were set along the sides of the tail system along horizontal planes. The tail rotor was set to face the portside of the aircraft.
Crew accommodations amounted to two pilots in the forward cockpit and up to six passengers in the main cabin.
Power for the ARH-70 was supplied from a single Honeywell HTS900-2 turboshaft engine of 970 shaft horsepower. This powerplant could supply the airframe a top speed of 161 miles per hour with a cruise speed of about 130 miles per hour. Her range was listed at 186 miles with a service ceiling equal to 20,000 feet. Empty weight registered at 2,598lbs with a maximum take-off weight equal to 5,000lbs.
As an armed reconnaissance helicopter and as in the OH-58D before it, the ARH-70 was intended to carry a rather modest arrangement of weaponry. Primary hitting power was to be supplied y a 1 x GAU-19 series 0.50 caliber Gatling gun fitted to an outboard pylon as well as Hydra 70 2.75-inch (70mm) rockets, also on an outboard pylon.
Although referred to in a few official media reports under the designation of ‘Arapaho’, this name was never officially assigned to the ARH-70 product.
Bell ARH-70A (Arapaho) Engine: 1 x Honeywell HTS900-2 turboshaft, 970shp Rotor: four-blade main rotor and two-blade tail rotor. Length: 34.68ft (10.57m) Height: 11.68ft (3.56m) Empty Weight: 2,597lbs (1,178kg) Maximum Take-Off Weight: 5,000lbs (2,268kg) Maximum Speed: 161mph (259kmh; 140kts) Maximum Range: 186miles (300km) Service Ceiling: 20,000ft (6,096m) Accommodation: 2 + 6 Hardpoints: 2
With the design definition launched in 1993, the Bell 407, developed from the 206L-4 offered wider cabin, 815 shp 250-C47B derated to 675 shp for takeoff and four main rotor blades. From the windscreen pillars the cabin swells outwards to a width 178 mm more than the LongRanger’s, not tapering in again until it meets the baggage compartment forward bulkhead. Aft of that it’s normal LongRanger, although with a different tail rotor system. The extra width is gained through curved door pillars and skins of carbon fibre composites. Cabin windows are greatly enlarged, coming down to the level of the windscreen and curving well up towards the cabin roof. The doors are interchangeable between 407s, handles are flush-mounted car-type.
The LongRanger’s extra left-hand cabin door is retained for loading a stretcher, with the aft-facing left-hand seat wider than its counterpart behind the pilot. The rear seat usually takes three passengers, but in the VIP configuration the centre space is taken by a folding armrest and there’s adequate room for four passengers in the main cabin. Lap and inertia reel shoulder harness is supplied for all passenger seats.
Bell used the four-blade main rotor and complete tail rotor drive train from the OH-58D Kiowa Warrior, and the transmis¬sion also comes from the OH-58D, with larger bearings and redesigned gears to increase fatigue life. The four 255 mm chord composite blades (Nomex honeycomb core, glass fibre reinforced plastic spar and skin) have tapered tips and unlimited fatigue life, and are attached to a flexible GFRP yoke which accom-modates flapping motion, with elastomeric dampers and bearings for lead-lag and pitch-change motion. A Frahm damper on top of the hub takes care of rotor vibration, and the transmission is attached to the airframe by SAVITAD (system for attenuating vibration independent of tuning and damping) which comprises two beams with elastomeric mounts and retained by springs.
The “avoid curve” is at 800 ft or 70 kts, almost twice that of the JetRanger. The low-inertia rotor also leads to a restriction in climb rate to 2000 ft/min. Although the 407 is capable of much more, over 4000 ft/min. Although the tail rotor system is taken from the OH-58D, the Kevlar/Nomex blades are longer and give enough authority to allow takeoffs in 35 kt winds from any direction. Tail rotor control is also hydraulic. Normal MTOW is 2267 kg, increased to 2499 kg with an external jettisonable load, as the gross weight is dictated by the landing skids and structure. Maximum external load is 1200 kg, but for normal passenger use it can take full fuel and seven people with light baggage and still be under gross weight.
The Rolls-Royce Allison 250-C47B turboshaft is controlled by a full-authority digital engine control system, the first to be fitted to a single¬ turbine light helicopter.
The 407 can handle slopes 5 degrees nose down or 10 degrees nose up or to either side, due in part to a pivoted rear undercarriage cross member.
A proof of concept demonstrator featuring bulged cabin door, a four blade rotor system (off the 406) and Allison 250-C47 turboshaft. A Law Enforcement demostrator was demonstrated in 2002, with a Rolls-Royce/Allison 250-C47B engine.
The concept demonstrator 407 (N407LR) was first flown on 21 April 1994 (standard Bell 206L-3 modified with tailboom and dynamic system of military OH-58D, plus sidewall fairings to simulate broader fuselage), and the programme was first revealed at Heli-Expo ’95, Las Vegas, January 1995. Two prototype/ pre-production 407s (C-GFOS and C-FORS) were first flown on 29 June and 13 July 1995, respectively.
The first producrion airframe (C-FWQY/N407BT) was flown 10 November 1995 and Transport Canada certification was received on 9 February 1996 with FAA certification following on 23 February. The first customer delivery was at Heli-Expo ’96, Dallas, in February 1996. A MoU of June 1996 provided for licensed assembly and marketing by Dirgantara (formerly IPTN) of Indonesia.
After extensive flight testing in the wake of three accidents, Transport Canada and the FAA approved an increase in the Bell 407’s maximum speed to 130 kt. from 100 kt., and company officials expected to restore the light helicopter’s 140-kt. never exceed speed (Vne) by the third quarter of 1999.
The latest approval is predicated on compliance with a Bell Helicopter Textron Alert Service Bulletin (ASB) that calls for installation of a redesigned tail rotor hub and blades as well as addition of mechanical stops on the anti-torque pedals. A Bell official said the stops restrict left pedal travel to 20.75 deg. from 28 deg., but right pedal travel remains at 14 deg.
In addition, the hub design moves the tail rotor centerline outboard 0.86 in. and provides an additional 2.4 in. of clearance between the tail boom and the tail rotor blades at maximum flapping angle. The chief performance penalty is reduced tail rotor authority at high altitudes, a Bell official said. The company has begun incorporating the changes into production 407s at its facilities in Mirabel, Quebec.
Bell also plans to provide parts to complete the modifications at no expense to operators in the field. According to the official, there were more than 350 of the single-engine 407s in operation worldwide in 1999. The helicopter entered service in 1996.
Company engineers and test pilots developed ancl evaluated the latest fix during a series of special flight tests in March and April that exceeded normal Transport Canada certification requirements by a significant margin, the official said. The tests centered on flying a 407 at 130 kt. indicated airspeed and using each anti-torque pedal to its mechanical stop in less than 0.4 sec. Although the abrupt applications were applied repeatedly, the tail rotor blades did not contact the tail boom structure and several inches of clearance were maintained, he said.
The 130-kt. approval comes about two months after Bell began conducting a series of special flight tests to increase Vne above a 100-kt. limit imposed on the aircraft early in 1999. The restriction was imposed after the tail booms of three 407s were severed following left pedal inputs. The first accident occurred in 1997 in the U.S., the second in 1998 in South Africa, and the third occurred in Brazil.
According to a Bell official, investigation has revealed that each f the accidents was cause by a sudden, full input of the left tail rotor pedal at cruise airspeed.” The sudden input “caused exceptional flapping (deflection) of the tail rotor” blades that damaged pitch stops and the pitch control links. As a result, the blades struck the tail boom aft of the horizontal stabilizers, severing it. The cause of the pedal input, however, has not been fully explained but pilot error is not being ruled out.
To reinstate the 407’s original 140-kt. Vne, Bell was instrumenting a 407, at its Mirabel site, in preparation for beginning flight tests of a solenoid-operated airspeed sensing system that will automatically engage/disengage the pedal stops depending on airspeed. If the helicopter is flying below 50 kt. the stops will be retracted to permit 28 deg. of left pedal travel and maximum tail rotor authority. Above 55 kt., the solenoid will engage the stops and limit left pedal travel to 20.75 deg.
The system, which is redundant and features a mechanical override, will be standard equipment in the twin-engine Bell 427. That aircraft was completing certification by Transport Canada and FAA.
The 500th production Bell 407 was delivered in October 2001 to Pabst Air, Germany, and 550 had been delivered to operators in 45 countries by early 2003; fleet time then totalled more than 745,000 hours. Total of 62 delivered in 1999, 62 in 2000, 47 in 2001 and 33 in 2002. COSTS: US$1.37 million (1999) flyaway. Development cost were estimated as US$50 million, of which US$9 million provided by Canadian government.
Bell 407 Engine: One Rolls-Royce 250-C47B turboshaft, 606kW for T-O, 523kW Max continuous pwr: 630 shp Transmission rating: 503kW for T-O, 470kW continuous op Main rotor diameter: 10.7m Rotor speed: 413 rpm Length: 12.7m Height: 3.7m Take-off weight: 2267kg Empty weight: 1178kg Useful load: 1058 kg. Standard usable fuel: 484 lt Optional aux fuel: 72 lt Max speed at sea level: 252km/h Vne: 204km/h / 140 kts Max cruise: 133 kt. LR cruise: 121 kt Hovering ceiling, OGE: 2470m / 12,200 ft Hovering ceiling, IGE: 3440m / 10,450 ft Service ceiling: 5460m Max ROC: 2000 fpm Range: 608km Loiter @ 60 kt: 3.8 hr. Internal payload: 1089kg External payload: 1200kg Crew: 1 Passengers: 6
Bell announced the development of a new combat helicopter on 28 September 1971, derived from the Model 209 and 211, with company funds, with a 1.10m longer fuselage supporting a larger diameter rotor measuring 14.63m. Both the main and tail rotors had wider chord blades and the main rotor blades had double swept tips to reduce noise levels and improve performance at high speed. The nose was also modified to accept new apparatus, the available space for ammunition was increased, and the wing span was taken to 3.96m. A redesigned tail assembly was used with a lower fin for improved longitudinal stability. It also had the transmission, wide-chord two-blade main rotor and drive train of the Model 211 HueyTug. Design work was begun by a team led by Joe Tilley and construction started in January 1971. Two prototypes of the Model 309 Kingcobra were built. The first (c/n 2503, registered N309J), which flew on 10 September 1971 at Fort Worth with Gene Colvin at the controls, was offered to the Marines with Turbo Twin Pack T400-CP-400 engines, while the second prototype (which flew in January 1972) was offered to the Army with a 2890shp Lycoming T55-L7C turbine of the Model 211, derated to 2050 on take-off. The KingCobra incorporated new avionics and systems to fulfill its anti-tank mission (inertial navigation system, APN-198 radar altimeter, fire-control computer, multi-sensor sight, head-up display, helmet sighting system, FL-33 FLIR, low-light level television and, of course TOW guidance system). Armament included provision for sixteen TOW missiles under extended stub wings and a General Electric chin-turret housing a three-barelled 20mm Gatling gun with 1345 rounds. On 11 April 1972, the first prototype was damaged in an accident. To meet future Army needs it was decided to convert the twin-engined 309 into single-engined configuration. As expected, on 9 August, 1972, the Army finally cancelled the Cheyenne programme and in due course two helicopter manufacturers, Sikorsky and Bell, submitted proposals for a less sophisticated aircraft, the Model S-67 and the Model 309 respectively. Tests and demonstrations were successfully conducted with both aircraft, but the Army set up new requirements and opened a new contest within the Advanced Attack Helicopter programme (AAH) which would eventually lead to the selection of the MDD/Hughes AH-64 Apache. The Bell Model 309 (N309J) is now preserved by the US Army Aviation Museum in Fort Rucker, Alabama.
Bell 309 Kingcobra Engine: 1 x Lycoming T55-L7C turboshaft, 2155kW Main rotor diameter: 14.63m Length: 14.63m Height: 4.11m Take-off weight: 4510kg Empty weight: 2890kg Gross weight: 6350kg Max speed: 330km/h
At the beginning of the 1970s a more powerful variant of the Model 205 (UH-1H) had been studied in which a 1,900shp Lycoming T53-L-702 turboshaft had replaced the standard 1,400shp T-53-L13 unit. The version, designated Model 214 HueyPlus, also retained the main rotor and tail rotor drive systems and the larger two-blade rotor of the Model 309 KingCobra (composite elasto¬meric), these offering better high speed and weight performance as well as reduced noise. The airframe was also strengthened including the pylon structure and fuselage. The Model 214 prototype flew for the first time at Arlington in October 1970 powered by a 2185kW Avco Lycoming LTC4B-8D turboshaft engine. Development of the HueyPlus progressed steadily until 1972 when Iranian Army Aviation approached Bell for the design of a UH-1 derivative which could be operated in hot and high conditions. Several hundreds of this new type of helicopter would be delivered together with some two hundred AH-1J Cobras. A $500 million contract for 293 machines was signed on 22 December, 1972, by the US Army, acting on Iran’s behalf. During the first phase of this programme, Bell built three additional prototypes of the Model 214. These were powered by 2,050shp Avco Lycoming T55-L-7C turbo-shafts, and in August 1972, one of them was shipped to Iran for evaluation. The tests were considered successful and Bell moved on to the Model 214A which was the production model. On this variant, power was increased further by the installation of a 2,930shp Avco Lycoming LTC4B-8D turboshaft which permitted operation at a greater gross weight. Three prototypes of the Model 214A were prepared by Bell (c/n 27001/27003), the first (N214J) making its maiden flight on 13 March, 1974. The second prototype flew in April 1974 and the third in May. Flight testing and certification were resumed in the following year. The first production 16-seat Model 214A (c/n 27004) was taken in charge by the Iran Imperial Army Aviation (IIAA) on 26 April, 1975, which gave them the name Isfahan. Three days later, on 29 April, this aircraft with Maj-Gen Manouchehr Khosrowdad, commander of the IIAA, and Clem A Bailey, Bell’s assistant chief production test pilot, at the controls, established five new world records in the FAI Class E-1e. The helicopter reached a maximum altitude of 9070m and sustained a horizontal altitude of 9010m for 30 seconds. It also climbed to 3000m in 1min 58sec; to 6000m in 5min 13.2sec and to 9000m in 15min 05sec. Subsequently, 39 generally similar aircraft, but with specific equipment for SAR operations, were delivered to the Iranian Air Force under the designation Bell Model 214C. The second batch was ordered in February 1976, and delivered between January 1977 and March 1978. A third batch of six Model 214As was ordered in March 1977 and this order was completed by the autumn of 1978. The last Model 214A of the first batch was completed on 19 December, 1975. Known as Model 214B BigLifter, this helicopter received FAA type certification on 27 January, 1976, but saw limited success and no more than seventy were produced. The Model 214B was externally similar to the Model 214A with the exception of an additional window in the side sliding door. Other differences included a fire-fighting system and new avionics. The Model 214B-1 variant was certificated under a different weight specification. In its Isfahan plant, Iran intended to produce a larger and more powerful variant of the Model 214A capable of carrying up to 16 people and incorporating a stretched and widened fuselage. A Model 214A was modified by Bell with the installation of two 2,250shp General Electric T700/T1C turbo-shafts and tested in Iran in February 1977. The definitive Model, known as Model 214ST (ST stood for ‘Stretched Twin’, but this was later modified to ‘Super Transport’), had its fuselage stretched by 2.44m. Bell assembled three prototypes (two for commercial certification and one of the military variant, c/n 18401/ 18403). Bell initiated the production of a first batch of 100 Model 214ST in November 1979. The first prototype (c/n 18401, N214BH) flew on 21 July, 1979. The production examples were powered by 2,930shp Avco Lycoming LTC4B-8Ds driving a large five-blade rotor with Noda-Matic head. In 1982, the Model 214ST received FAA and CAA type certification for VFR and IFR operations. The 214ST is fully IFR certified and has a computer-controlled fly-by-wire automatic elevator trim system, plus a stability and augmentation control system and main rotor blade in-flight tracking system. A version with wheel undercarriage was certificated in March 1983. Designed for long-range offshore oil operations with cruise speeds of 140 knots, the 214ST operates to 650 kilometres range with 45 minutes reserve. Bell’s Super Transport can lift over three tons even on hot days at high altitudes. The Super Transport General Electric CT7-2A engine modules are designed for mechanical simplicity, requiring only 12 basic tools for line maintenance and module replacement. Options such as life rafts, pop-out floats, internal hoist or two 310 litre auxiliary tanks can be added.
Bell 214ST
Two versions were available, and the standard Model 214B was intended for a variety of purposes. They included operation as a 14-passenger transport with a crew of two; as a cargo lifter, with an external cargo hook certificated to carry a maximum load of 3629kg; in an agricultural role, carrying a very similar chemical load; or as a firefighter able to drop a total 2725 litres of fire retardant, carried in cabin and under-fuselage tanks. The alternative Model 214B-1 was certificated to different standards that allowed for operation at a lower gross weight with an internal load. The Model 214B was available to commercial operators from the receipt of certification on 27 January 1976 until production ceased in 1981.
The 214B BigLifter is derived essentially from the 204 and 205, and was specifically designed to better the lift capacity of any contemporary civil helicopter of the same power. The key to the type’s considerable lifting ability is the use of a 2930shp Lycoming T5508D turboshaft (the civil version of the T55-LTC4B-8D turboshaft powering the 214A and its search-and-rescue derivative, the 214C), flat-rated to 2250shp maximum output. The rotor and transmission are identical with those of the 214A, the transmission being capable of accepting up to 2050shp at take-off and 1850shp for continuous running. The rotor system is of an advanced type, the blades having swept tips and the hub featuring elastomeric bearings on the flapping axis. The twin-blade tail rotor has a hub which needs no lubrication. Other advanced features of the type are the use of an automatic flight-control system, with the capability of altitude maintenance and augmented stability; dual hydraulic systems; a nodalized suspension (Bell’s patented ‘Noda- Matic’ concept of 1972, by which the fuselage is suspended from points of no relative motion in the engine mounting) to reduce fuselage vibration by about 80%; and an engine decking that is also used as a maintenance platform for the engine, transmission and rotor hub. The 214B BigLifter carries to an extreme the Bell design philosophy of a twin-blade wide-chord main rotor, each of the blades having a chord of no less than 88.9cm. The transmission and rotor-drive systems are well proved by earlier use in the 214A, after development in the experimental KingCobra gunship helicopter. Although it is intended mainly as a weight-lifter, the 214B can carry up to 14 passengers in addition to its crew of two. As a weight-lifter, however, the 214B can carry up to 1814kg internally, or up to 3175kg externally on its cargo hook, which is cleared for flight with loads weighing up to 3629kg. This weight-lifting capacity is also useful in the agricultural role, in which up to 3629kg of chemicals or 3023 litres of liquid can be uplifted. The considerable liquid-carrying capability of the 214B is also useful for fire-fighting. The Model 214B-1 is intended for different certification standards, and is thus limited in the internal load-carrying role to a maximum take-off weight of 5670kg. Production began in 1981, deliveries started in 1982 and by the beginning of 1984, some twenty machines were in service and seventy-eight had been delivered by early 1988. Among the first operators were British Caledonian Helicopters (c/n 28109/28110; G-BKFN and G-BKFP) which operated offshore in the North Sea and People’s Republic of China. By 1992 some two hundred Model 214STs have been sold. The bulk of the Model 214ST production has found its way on to the civil market and only a few have been delivered to military customers: Brunei (one), Peru (eleven), Thailand (nine) and Venezuela (four) and Sultan of Oman’s Air Force which operated eight Model 214B/STs from Salalah during the war against Iraq in January/February 1991. The Bell 214ST features: ROTOR SYSTEM: Two-blade advanced technology main rotor. Each blade has a unidirectionally laid glass fibre spar, with a 45degree wound torque casing of glass fibre cloth. The trailing-edge is also of unidirectional glass fibre, and the space between spar and trailing-edge is filled by a Nomex honeycomb core. The entire blade is then bonded together by glass fibre wrapping, with the leading-edge protected by a titanium abrasion strip and the tip by a replaceable stainless steel cap. Two-blade tail rotor; interchangeable blades, each with a stainless steel leading-edge spar and covering, aluminium honeycomb core and glass fibre trailing-edge strip. Main rotor head incorporates elastomeric bearings. Second-generation Noda-Matic nodal suspension system. Nodal beam requires no lubrication. Main rotor brake standard. ROTOR DRIVE: Main transmission has a maximum rating of 1,752kW, maximum continuous rating of 1,454kW, and single-engine rating of 1,286kW. Combining, intermediate and tail rotor gearboxes, each with 1 hour run-dry capability. FUSELAGE: Conventional all-metal semi-monocoque structure, incorporating rollover protection ring. TAIL SURFACE: Electronically controlled elevator, which minimises trim changes with alterations of power and CG, and improves longitudinal stability. LANDING GEAR: Choice of energy absorbing non-retractable tubular skid-type or tricycle-type wheeled landing gear. POWER PLANT: Two 1,212kW General Electric CT7-2A turboshafts, connected to a combining gearbox. In the event of an engine failure, the remaining engine is capable of developing 1,286kW to provide continued flight capability. Standard fuel capacity 1,647 litres, contained in seven interconnected rupture-resistant cells, arranged to provide two independent fuel systems as required by FAR Pt 29. Single-point refuelling. Auxiliary fuel system optional, consisting of two tanks in rear of cabin, each of 329 litres capacity; 95 litre underseat auxiliary fuel tanks also available. Engine anti-icing and inlet screens standard. ACCOMMODATION: Standard seating for pilot, co-pilot and up to 18 passengers. Dual controls standard. Crew seats adjustable. Passenger seats in three rows across cabin plus a two-place bench seat on each side of rotor mast. Standard configuration offers utility or de luxe interiors with contemporary or energy attenuating seats. Jettisonable crew door each side. Large cabin door on each side for passengers or easy loading of cargo. Glass windscreens, with standard anti-icing system. Two emergency exits on each side. Baggage space aft of cabin, capacity 1.84cu.m. Passenger seating removable to provide 9.23cu.m of cargo capacity. Cabin heated and ventilated.
It was reported in July 1982 that Bell had obtained FAA certification for an increase from 16 to 18 passengers that can be carried in the 214ST Super Transports (plus two pilots).
Versions:
214A Powered by a 2,185kW (2,930 shp) Lycoming LTC4B-8D turboshaft engine, an improved version of the T55-L-7C fitted to the original Model 214A demonstrator when it went to Iran. It has the 1,528kW (2,050 shp) transmission and rotor drive system developed for the KingCobra experimental gunship helicopter and embodies Bell’s NodaMatic nodalised beam concept to minimise vibration. 296 delivered to the Iranian Imperial forces.
214B BigLifter Commercial version of the 214A, announced on 4 January 1974, providing better lift capability than any commercial helicopter then in production. Powered by a 2,183kW (2,930 shp) Lycoming T5508D turboshaft, it has the same rotor drive and transmission system as the 214A. The engine is flat-rated at a maximum 1,677kW (2,250 shp) and the transmission at 1,528kW (2,050 shp) for take-off, with a maximum continuous power output of 1,379kW (1,850 shp). Advanced rotor hub with elastomeric bearings on the flapping axis; raked tips to main and tail rotors. Other features include an automatic flight control system with stability augmentation and attitude retention; nodalised suspension; separate dual-hydraulic systems; a large engine deck which serves as a maintenance platform; addition of an engine fire extinguishing system; push-out escape windows in the cargo doors, and commercial avionics.
214B-1 As 214B, but with restricted internal gross weight of 5,669kg (12,500 lb).
214C Search and rescue variant of 214A. Total of 39 delivered to Iran.
214ST Stretched twin-engined military version originally developed for production and service in Iran; but later transformed into commercial transport.
Specifications:
Bell Model 214B Engine: 1 x Avco Lycoming T5508D turboshaft, 2185kW, 2050 hp Main rotor diameter: 15.24m Disc loading: 7 lb/sq.ft. Pwr loading: 4.7 lb/hp. Take-off weight: 6260k g / 13,800 lb Empty wt: 7696 lb Equipped useful load: 6059 lb. Payload max fuel: 3595 lb. Range max fuel/ cruise: 223 nm/ 1.5 hr. Range max fuel / range: 256 nm/ 2.0 hr. Service ceiling: 20,000 ft. Max cruise: 146 kt. Max range cruise: 131 kt. ROC: 2280 fpm. HIGE: 15,200 ft. HOGE: 10,700 ft. Max sling load: 8000 lb. Standard fuel capacity 772 litres Max fuel aux tank: 1,434 litres. Accommodation: One or two pilots and 14 to 15 passengers.
Bell Model 214ST Super Transportghts Engine: 2 x General Electric CT7-2 turboshaft, 1212kW, 1195 shp Rotor diameter : 52.165 ft / 15.9 m No. Blades: 2. Disc loading: 8.2 lbs/sq.ft. Power loading: 5.4 lbs/hp Max take off weight : 17507.7 lb / 7940.0 kg Weight empty : 10143.0 lb / 4600.0 kg Max ramp weight: 17,500 lbs Max useful load: 7987 lbs. Max landing weight: 17,500 lbs. Max sling load: 8000 lbs. Length with rotors turning: 18.95m / 62.1 ft Fuselage length : 50.197 ft / 15.3 m Height : 15.748 ft / 4.8 m Max. speed : 140 kt / 259 km/h Normal cruise @ 3000 ft: 139 kts. Fuel flow @ normal cruise: 906 pph. Endurance @ normal cruise: 3 hr. Initial climb rate : 1771.65 ft/min / 9.0 m/s Service ceiling : 12598 ft / 3840 m Hover in ground effect: 7800 ft Range : 463 nm / 858 km Hovering ceiling, IGE: 3170m Fuel capacity : 435 gal / 1647 l Crew : 2 Passengers : 18
In 1964, the conversion of a standard UH-1D to a twin-engined configuration was funded by Bell. Work was done in Fort Worth, and by the spring of 1965, the prototype Model 208 Twin Delta was ready to fly. Its powerplant comprised two Continental T72-T-2 Model 217 turbo-shafts mounted side by side and driving, via a combining gearbox, a single output shaft. Designated XT67-T-1, this powerplant offered 1,240shp for take-off. The maiden flight was made on 29 April, 1965.
On 1 May 1968 the Bell Helicopter Company announced that following negotiations with the Canadian government and Pratt & Whitney Aircraft of Canada, it had been agreed to proceed with the development of a new helicopter based upon the airframe of the Bell Model 205/ UH-1H Iroquois, of which the first of 10 for the Canadian Armed Forces (CAF) had been delivered on 6 March 1968 under the designation CUH-1H. Power-plant of the UH/CUH-1 consisted of a 1044kW Avco Lycoming T53-L-13 turboshaft engine. The CAF considered that the incorporation of twin turboshaft engines would provide a number of benefits, and this led to development of the initial military Bell Model 212 and the Pratt & Whitney Aircraft of Canada (PWAC) PT6T power-plant for it. This programme was initiated as a joint venture, financed by Bell, the Canadian government and PWAC.
The PT6T Twin-Pac designed and developed by PWAC, consisted of two turboshaft engines mounted side-by-side and driving, via a combining gearbox, a single output shaft. This had an output in its initial production form of 4.66kW/kg, compared with 4.19kW/kg for the already-developed Lycoming T53 turboshaft. As installed in the Model 212 the PT6T-3 is limited to an output of 962kW for takeoff. In the event of a failure of one of the two turbines, sensing torquemeters in the combining gearbox signal the remaining turbine to develop a power output ranging from 764kW to 596kW, for emergency and continuous operation respectively.
Initial deliveries of military Model 212s were made to the USAF in 1970.
This variant, known as Model 212, was to have a two-blade all-metal semi-rigid rotor, and accommodate a pilot and up to fourteen passengers and, in its military variant, armament could include 7.62mm MAG pod machine-gun systems, 70mm air-to-ground rocket launchers (7 or 19 rounds), side-mounted 12.7mm or 7.62mm machine-guns. The airframe is generally similar to that of the UH-1H Iroquois, with an all-metal fuselage structure, and skid landing gear. A 14-passenger commercial version known as the Twin Two-Twelve was developed more or less simultaneously, this differing from the military model primarily in its cabin furnishing and avionics equipment. The Twin Two-Twelve gained FAA Transport Type Category A certification on 30 June 1971, and the type has since gained certification for IFR operation, requiring a new avionics package, new instrument panel, and stabilisation controls for such use. On 30 June 1977 it became the first helicopter to be certificated by the FAA for single-pilot IFR operation with fixed floats.
Bell 212
In June 1980, an improved variant of the PT6T-3, the PT6T-3B, was introduced which besides giving more power (1,800shp), also offered improved single-engine performance.
In mid-1988, producton of the Model 212 was transferred to Bell’s Canadian factory.
The order for a first batch of fifty helicopters was placed by the Canadian Armed Forces (under designation CUH-1N, later modified to CH-135) and the first Model 212 flew in April 1969. More orders soon followed, both civil and military: seventy-nine UH-1Ns for the US Air Force; forty UH-1Ns for the US Navy and twenty-two UH-1Ns for the US Marine Corps; 159 more being ordered later by the US Navy and Marine Corps. The enhanced safety offered by the Twin-Pac powerplant has resulted in many sales to operators who provide support to offshore gas/oil prospecting and production companies, as well as to air taxi organisations. Eight Model 212s were delivered to the Civil Air Authority of China during 1979, and were the first helicopters supplied to the People’s Republic of China by a US manufacturer.
Bell 212
The 212 features an all-metal two-blade semi-rigid teetering main rotor with interchangeable blades; underslung feathering axis head; rotor brake optional. Fully powered hydraulic controls; gyroscopic stabiliser bar above main rotor; automatic variable incidence tailplane; IFR versions have large fin above cabin to improve roll-yaw responses during manual instrument flying. The metal main rotor blades have extruded aluminium nose sections and laminates; glass fibre safety straps provide redundant load path; fuselage conventional light metal. Tubular skid type. Lock-on ground handling wheels, high skid gear, fixed floats and emergency pop-out nylon float bags optional. Pratt & Whitney Canada PT6T-3B Turbo Twin-Pac, comprising two PT6 turboshafts coupled to combining gearbox with single output shaft. Engine rating 1,342kW for T-O, 1,193kW maximum continuous; OEI rating 764kW for 2.5 minutes, 723kW for 30 minutes. Transmission rating 962kW for T-O, 846kW maximum continuous and 764kW OEI. Five interconnected rubber fuel cells, total usable capacity 818 litres. Two 76 or 341 litre auxiliary fuel tanks optional, to provide maximum possible capacity of 1,499 litres. Single-point refuelling on starboard side of cabin. Oil capacity 11.5 litres for engines, 8.5 litres for transmission. Pilot and up to 14 passengers. Dual controls optional. In cargo configuration, has total internal volume of 7.02 cu.m, including baggage space in tailboom, capacity 181kg. Forward-opening crew door each side of fuselage. Two doors each side of cabin; forward (jettisonable) door hinged to open forward, rear door sliding aft. Accommodation heated and ventilated.
The 212 has been manufactured under license in Italy by Agusta as the Agusta-Bell AB.212, who built a demonstration prototype in 1971, initially in a civil configuration for VIP transport, but later transformed into a military configuration (corresponding to the UH-1N). These are generally similar to the American-built aircraft, but Agusta has developed an ASW version designated AB.212ASW. Structural strengthening took place, plus the provision of deck restraint gear, and the PWAC PT6T-6 Twin-Pac turboshaft rated at 1398 kW for take-off. This version has been exported to Greece, Turkey, Peru, and Spain. Distinctive features of the AB-212 antisubmarine helicopter include a special anticorrosive treatment for the powerplant, a search radar housed in a dome on the cabin roof, special electronics, sonar, antisubmarine and antiship armament, consisting either of two Mk.44 antisubmarine torpedoes, two AS-12 missiles, or two antiship missiles, depth charges and flares. The crew consists of two pilots and two operators. The Italian Air Force became interested in the Agusta AB-212 and acquired a few for air base rescue services.
Inside an 18-place Super Transport are wide and comfortable seats with adequate hip room and shoulder room. The cabin design provides superb passenger visibility.
The 212 has also been fitted with a four-blade rotor with redesigned blades. This variant, designated Model 412, has been in production in the USA and Italy since 1981. The four-blade rotor can also be fitted to the old 212s.
The US Marine Corps flies the VH-1N as a dedicated VIP transport.
The US Navy unit VXE-6 operates about six bright-red UH-1Ns in the Antarctic. In 1972, a UH-1N dropped a parachutist over McMurdo Sound, Antarctica for a record jump of 6247m.
100 UH-1N were to be rebuilt and upgraded to the UH-1Y configuration. The UH-1Y and AH-1Z feature zero-time airframes and 85% commonality, including two GE-T700 turboshafts, glass cockpits, four-blade all-composite main rotors and tail rotors, drive train, and hydraulic and electrical systems.
CH-135 Canadian version, originally CUH-1N. Total 50 delivered 1971/72.
UH-1N US Air Force, Navy and Marines version. Total 320 delivered.
UH-1Y Dynamic and avionics upgrade.
Twin Two-Twelve Civil version; first flight 16 April 1969; FAA certification 30 October 1970; FAA Category A transport certification 30 June 1971; IFR certification granted by FAA, UK CAA, Norwegian DCA and Canadian DoT; first-ever single-pilot IFR certification with fixed floats granted June 1977.
Bell212ST
AB212 Agusta-built version.
AB212ASW Agusta-built version for anti-submarine warfare.
Specifications
Bell 212 Engine: 1 x Pratt & Whitney (UACL) PT6T-3 Turbo Twin Pac, 1800 shp (flat rating 1250 shp) Rotor diameter: 48 ft 2.25 in / 14.69 m Fuselage length: 42 ft 4.75 in / 12.92 m Empty weight: 5549 lb / 2517 kg MTOW: 11,200 lb / 5080 kg Max speed SL: 109 kt / 126 mph / 203 kph Max ROC SL: 1745 fpm / 532 m/min Service ceiling: 17,400 ft / 5305 m Max range SL, no res: 237 nm / 273 mi / 439 km Crew: 1 Passenger capacity: 14 Interal cargo: 220 cu.ft / 6.23 cu.m Internal load: 5000 lb / 2268 kg
212 Twin Engine: 2 x P&W PT6T-3B coupled, 900 shp. TBO: 2500 hrs. Main rotor: 48 ft / 14.69m Seats: 15. Length: 57.3 ft. / 17.46m Height: 13.1 ft / 4.53m Max ramp weight: 11,200 lbs. Max takeoff weight: 11,200 lb / 5080kg Standard empty weight: 6143 lb / 2786kg Max useful load: 5057 lbs. Max landing weight: 11,200 lbs. Max sling load: 5000 lbs. Disc loading: 6.2 lbs/sq.ft. Power loading: 6.2 lbs/hp. Max usable fuel: 1455 lbs. Max rate of climb: 1420 fpm. Service ceiling: 14,200 ft / 4330m Hover in ground effect: 11,000 ft. Max speed: 100 kts. Normal cruise @ 3000 ft: 100 kts. Fuel flow @ normal cruise: 650 pph. Endurance @ normal cruise: 2 hr. Range: 420km
UH-1N Engine: 1 x P&WC PT6T-3B Twin Pac. Instant pwr: 1341 kW. Rotor dia: 14.69 m. MTOW: 5,084 kg. Payload: 2260 kg. Max speed: 121 kts. Max cruise: 115 kts. Max range (no reserve): 512 km. HIGE (@MAUW): 4750 ft. Service ceiling: 12,500 ft. Crew: 1. Pax: 14.
AB.212 ASW/ASV Engine: 1 x 1,875 shp (1398 kW) Pratt & Whitney Canada T400 (PT6T 6) Turbo Twin Pac with two gas turbine power sections. Instant pwr: 1342 kW. Rotor dia: 14.63 m (48 ft 0 in). Rotor disc area 173 9 sq.m (1,872.0 sq ft). Fuselage length: 12.9 m. Length overall 17.40 m (57 ft 1 in) Height 4.53 m (14 ft 10¼ in). No. Blades: 2. Empty wt: 3420 kg (7,540 lb). MTOW: 5070 kg (11,176 lb). Payload: 2335 kg. Max speed: 130 kts. HIGE: 3200 ft. HOGE: 1300 ft. ROC: 396 m/min. Fuel cap: 1350 lt. Range: 582 km. Max range with auxiliary tanks (no reserve) 667 km (414 miles). Crew: 3/4. Armament: two Mk 46 AS torpedoes or two depth charges or two anti ship missiles.
In March 1965, Bell initiated company-funded development of the proven Model 204 (UH-1B/-1C Iroquois) to produce an armed helicopter suitable for close-support/attack roles. Intended to provide the US Army with an interim AAFSS (advanced aerial fire support system) helicopter, it combined a new narrow, low-profile, tandem-seat fuselage with the rotor / transmission system / powerplant and tailboom of the UH-1C. First flown in prototype form on 7 September 1965, the new Bell Model 209 was evaluated by the US Army from December of that year, with orders for two pre-production and 110 production aircraft following during April 1966. Initially a 1400 shp Avco Lycoming T53 L 13 turboshaft engine was used to power the Army’s first production version, designated AH-1G, and named HueyCobra, the type was first delivered to the US Army in June 1967, and within two months the type was being used operationally in Vietnam. US Marine Corps interest in this helicopter resulted in 38 AH-1Gs being supplied from the US Army production line in 1969, pending initial deliveries of 49 of the AH-1J SeaCobra variant ordered by the US Marine Corps in May 1968. Examples generally similar to the US Army’s AH-1G have been supplied to the Spanish navy (eight, designated Z.14) and Israel (six). The HueyCobra has small stub-wings that serve the dual purpose of offloading the rotor in flight, and of carrying armament that, in the case of the AH-1G, can include folding-fin rockets or Minigun pods. Additionally, this version mounts beneath the nose an M-28 turret that can house two Miniguns, or two 40-mm grenade-launchers, or one of each. Armour protection is provided for the crew in the form of Noroc side panels and seats, with other vital areas of the helicopter protected by panels of the same mat-erial. The Cobra features Kaman composite blades, fitted from 67th AH-1P onwards, tolerate hits by 23mm shells, have tungsten carbide bearing sleeves and outer 15% of blade is tapered in chord and thickness; tailboom strengthened against 23mm hits; airframe has infra-red suppressant paint finish. IR suppression nozzle on AH-1F. Flat-plate canopy has seven planes of viewing surfaces, designed to minimise glint and reduce possibility of visual detection during nap of the earth (NOE) flying; it also provides increased headroom for pilot. Improved instrument layout and lighting, compatible with use of night vision goggles. Improved, independently operating window/door ballistic jettison system to facilitate crew escape in emergency.
The Cobra was armed with an M65 system with eight Hughes TOW missiles, disposed as two two-round clusters on each outboard underwing station. Inboard wing stations remain available for other stores. M28 (7.62/40mm) turret in earlier HueyCobras replaced by new electrically powered General Electric universal turret, designed to accommodate 20mm weapon and improve standoff capability, although only 20mm M197 three-barrel cannon (with 750 rounds) mounted in this turret. Rate of fire 675 rds/min. Turret position is controlled by pilot or co-pilot/gunner through helmet sights, or by co-pilot using M65 TOW missile system’s telescopic sight unit. Field of fire up to 110degs to each side of aircraft, 20.5degs upward and 50degs downward. Also equipped with Baldwin Electronics M138 wing stores management subsystem, providing means to select and fire, singly or in groups, any one of five types of external 70mm rocket store. These mounted in launchers each containing 7 or 19 tubes, additional to TOW missile capability.
A US Army production version of the Hueycobra attack helicopter is the TOW-armed AH-1F (Model 209) with flat-glass canopy, laser rangefinder and tracker, low airspeed sensor, fire-control computer, Doppler navigation, nap-of-the-earth and secure communications, and infrared suppression and jamming. The fully upgraded AH-1F entered production with the 199th new-build AH-1S, following 100 AH-1S and 98 Up-Gun AH-1S. A more advanced version of the single turbine Model 209, which has the military designation AH 1S, was in production for the U.S.Army. Power was provided by a 1,800 shp Avco Lycoming T53 L 703 turboshaft engine, and in addition to airframe improvements there are advanced avionics and equipment to enhance the flexibility and capability of the armament which is deployed.
Bell AH-1F HueyCobra
378 earlier AH-lGs were fitted with TOW mis¬siles and designated Mod AH-1S (Modified). The JGSDF received its first AH-1F in December 1984, from a requirement for 54. Fuji is assembling these Hueycobras under licence. First twin-engined Cobra was AH-1J SeaCobra, delivered from mid-1970. The AH-1J traded the single Lycoming T53 turboshaft for a Pratt & Whitney PT6T-3 TwinPac engine.
The AH-1W was substantially redesigned to take a pair of 3250shp General Electric T700 engines in which guise it was named “SuperCobra”. The USMC took delivery of the first of 44 new AH-1W SuperCobras in March 1986. The AH-1W SuperCobra is a version of the US Marine Corps AH-1 SeaCobra attack helicopter, itself a twin-engined develop¬ment of the US Army’s single-engined AH-1 HueyCobra that first flew in September 1965 in direct response to the requirements of the Vietnam War. In 1980 Bell was loaned an AH-1T Improved SeaCobra, and this was re-engined with two T700-GE-700 turboshafts with a combined output of 3,200 shp (2,386 kW) for improved performance with a heavier and more diverse warload. The AH-1T+ “production” version comprised 44 AH-1T conversions with slightly more power, a new combining gearbox, and revised electronics including a head-up display for the pilot and an improved defensive suite. The type entered service in 1987 with the revised designation AH-1W, and provides the USMC with an advanced capability for support of beach-head operations from landing ships lying offshore. The 65 per cent increase in available power allows up to eight TOW or Hellfire missiles to be carried.
Bell AH-1W
The Bell Model 249 was an AH-1S fitted with a four-blade rotor, and was offered with TOW or HOT missile installations. A proto¬type Model 249 flew in December 1979, using a Model 412 rotor system. The original Model 209 prototype first flew on September 7, 1965. Designations include Modified AH-1S, which covers 197 AH-lGs and the 93 AH-1Qs with upgraded gearbox, transmission, improved rotor, T53-L-703 engine, and TOW-capability; 100 generally similar Production AH-1S, being new production aircraft with advanced avionics, instrumentation, and systems; 98 Up-Gun AH-1S, generally as the Production AH-1S but with an improved turret and weapon management systems; and the Modernised AH-1S of which 126 new production aircraft have been ordered incorporating the improvements embodied in the other AH-1S aircraft, plus advanced nay/coin, avionics, and protection systems. These are now known as AH-1F to avoid confusion with other variants AH-1T Improved SeaCobra: generally improved version of the AH-1J, incorporating an uprated T400-WV-402 powerplant, the dynamic system of the Bell Model 214, and the fuselage lengthened by 1.09m (3ft 7 in); 57 built, and equipped for operation with TOW missiles AH-1W SuperCobra: new USMC version with two GE T700-GE-700 engines, producing 1260-kW (1,690-shp) each. Better protection and avionics are incorporated. Conversion applied to AH-1T aircraft Model 249: company designation of a Modernised AH-1S which was equipped and tested with an advanced four-blade main rotor as developed for the Bell Model 412. The first two of an initial batch of five AH-1W SuperCobra ordered for the Turkish Army Aviation were delivered in July 1990. They were powered by GE T700-GE-401 turboshafts.
Building a HueyCobra requires 38,500 hours of factory-worker time.
The Bell 209 Super Cobra features a stepped tandem seating and stub-wings for armament. Two-blade main rotor, similar to that of Bell 214, with strengthened rotor head incorporating Lord Kinematics Lastoflex elastomeric and Teflon-faced bearings. Blade aerofoil Wortmann FX-083 (modified); normal 311 rpm. Tail rotor also similar to that of Bell 214 with greater diameter and blade chord; normal 1,460 rpm. Rotor brake standard. Stub-wings have NACA 0030 section at root; NACA 0024 at tip; incidence 14degs; sweepback 14.7degs. AH-1Z will incorporate new four-blade rotor system and transmission. Main rotor blades have aluminium spar and aluminium-faced honeycomb aft of spar; tail rotor has aluminium honeycomb with stainless steel skin and leading-edge. Airframe conventional all-metal semi-monocoque. Non-retractable tubular skid type on AH- 1W. Ground handling wheels optional. Two General Electric T700-GE-401 turboshafts, each rated at 1,285kW. Transmission rating 1,515kW for take-off; 1,286kW continuous; AH-1Z transmission flat rated at 1,957kW, Fuel (IPS) contained in two interconnected self-sealing rubber fuel cells m fuselage, with protection from damage by 12.7mm ballistic ammunition, total usable capacity 1,128 litres; AH-1Z has larger stub-wings, containing 379 litres of additional fuel. Gravity refuelling point in forward fuselage, pressure refuelling point in rear fuselage. Provision for carriage on underwing stores stations of two or four external fuel tanks each of 291 litres capacity; or two 379 litre tanks; or two 380 and two 290 litre tanks; large tanks on outboard pylons only. Oil capacity 19 litres. Crew of two in tandem, with co-pilot/ gunner in front seat and pilot at rear in AH-1W; crew stations are interchangeable in AH-1Z. Cockpit is heated, ventilated and air conditioned. Dual controls; lighting compatible with night vision goggles, and armour protection standard. Forward crew door on port side and rear crew door on starboard side, both upward-opening. Inflatable body and head restraint system by Simula of Phoenix, Arizona, nearing end of development in mid-1995; retrofit provisions installed in 1996 production, with system incorporated in 1997 production. Electrically operated General Electric undernose A/A49E-7(V4) turret housing an M197 three-barrel 20mm gun. A 750-round ammunition container is located in the fuselage directly aft of the turret; firing rate is 675 rds/min; a 16-round burst limiter is incorporated in the firing switch. Either crew member can fire the gun, which can be slaved to a helmet-mounted sight/aiming device. Gun can be tracked 110degs to each side, 18degs upward, and 50degs downward, but barrel length of 1.52m makes it imperative that the M197 is centralised before wing stores are fired. Underwing attachments for up to four LAU-61A (19-tube), LAU-68A, LAU-68A/A, LAU-68B/A or LAU-69A (seven-tube) 70mm Hydra 70 rocket launcher pods; two CBU-55B fuel-air explosive weapons; four SUU-44/A flare dispensers; two M118 grenade dispensers; Mk 45 parachute flares; or two GPU-2A or SUU-11A/A Minigun pods. Provision for carrying totals of up to eight TOW missiles, eight AGM-114 Hellfire missiles, two AIM-9L Sidewinder or AGM-122A Sidearrn missiles, on outboard underwing stores stations. Canadian Marconi TOW/ Hellfire control system enables AH-1W to fire both TOW and Hellfire missiles on same mission.
AH-1W Upgrades: Following abandonment of the proposed Integrated Weapon System (IWS) project in July 1995 and the Marine Observation and Attack Aircraft programme which was intended to provide a replacement for both the AH-1W SuperCobra and the UH-1N Iroquois, the US Marine Corps has opted for a two-stage upgrade of the AH-1W, allowing it to be retained in the active inventory until about 2030. Phase 1 concerned installation of a Night Targeting System (NTS), under which USMC AH-1Ws fitted with the Israeli Tamam laser NTS for dual TOW/Hellfire day, night and adverse weather capability. Conversion of a prototype (162533) was authorised in December 1991, with an initial batch of 25 sets being built by Tamam for delivery from January 1993; joint production with Kollsman was approved in May 1994. A total of 250 sets was required by the USMC, with further sets produced for Turkey and Taiwan. Deliveries of modified aircraft to operational units of the USMC began in June 1994. A further improvement programme, involving installation of an Embedded Global Positioning System/ Inertial Navigation System (EGI), has been undertaken. Two prototype conversions (162532 and 163936) were delivered to test units for trials in November 1995 and March 1996, with EGI installed on new-build aircraft from Lot 9 onwards, as well as older AH-1Ws as a retrofit programme. Phase 2 entails installation of the Bell 680 four-blade rotor, offering a 70% reduction in vibration; formerly designated AH-1W, but now known as AH-1Z. Initial trials of the four-blade rotor system were undertaken with AH-1W 161022; bench testing of the new drive system began in second quarter of 1999 and was completed in first quarter of 2000. Bell also demonstrated 30-minute run-dry capability of new intermediate and tail rotor gearboxes in Match 2000. The AH-1Z will be fitted with a new four-blade, all-composites, hingeless/ bearingless rotor system; four-blade composites tail rotor; a new transmission rated at 1,957kW; endplates on horizontal tail surfaces and new wing assemblies able to carry twice the number of anti-armour missiles, as well as more fuel and additionally permitting concurrent carriage of two air-to-air self-defence missiles. Lockheed Martin selected to develop and manufacture AN/AAQ-30 Hawkeye advanced target sighting system (TSS), with work on US$8 million, 54 month, engineering development and integration programme beginning in July 1998. TSS features imaging technology by Wescam of Canada and Lockheed Martin’s Sniper third-generation FLIR, as well as colour TV camera, laser ranger, spottracker and designator. Also to feature on the AH-1Z are ‘glass cockpits’, Northrop Grumman (formerly Litton Industries) has been selected as prime contractor for this aspect of the upgrade. Digital transfer of information on tactical situation, weaponry and flight data will enable crew interchangeability and allow AH-1Z to be flown from either front or rear seat, Major subcontractors include Rockwell Collins, which will supply active matrix liquid crystal displays (AMLCDs); Smiths Industries (fire-control system); Meggitt Avionics (standby air data and inertial sensing devices); and BAE Systems (air data computers). Other elements of the upgrade include new stores management system, onboard systems monitoring, mission data loader, HOTCC (hands on throttle, collective and cyclic) controls, airborne target handover system and a new EW suite. A US$310 million cost-plus-fixed-fee contract was awarded to Bell in November 1996, for design, development, fabrication, installation, test and delivery of three engineering development AH-1W SuperCobra Upgrade Aircraft. Assembly of first AH-1Z begun at Hurst, Texas, in April 1999, by which time 85% of drawings had been released, with design work due for completion by end of 1999. Initial AH-1Z (162549, c/n 59001) completed final assembly in second quarter of 2000 and moved to Bell Flight Research Center at Arlington, Texas, for installation of instrumentation and functional testing that included restrained ground running which was completed in October 2000. Formal roll-out at Arlington on 20 November 2000, with first flight following on 7 December; subsequently redesignated as NAH-1Z and may eventually adopt new identity of 166477. Second development aircraft (163933/166478, c/n 59002) was due to fly in 2001, but handling quality problems that emerged early in flight test programme necessitated redesign of horizontal stabiliser assembly and caused delav; this eventually flew for first time on 4 October 2002, having been forestalled by third development aircraft (162532/ 166479, c/n 59003), which made its maiden flight on 26 August 2002. By mid-November 2002, all three aircraft had accumulated 390 flight hours, demonstrating 296km/h cruise and 407km/h maximum speed. Programme includes flight test and evaluation at Patuxent River, Maryland, to where first AH-IZ was airlifted by C-5 Galaxy on 31 March 2001. Weapons testing will take place at Yuma Proving Ground, Arizona with other trials at China Lake, California. Operational Test and Evaluation (OT&E) due to begin in fourth quarter of FY03 and will mostly be conducted at Patuxent River. Testing of full-scale AH-IZ structural test article at Arlington began in April 2000; on 22 November 2002, significant milestone passed with completion of 20,000 hour fatigue life demonstration, but further fatigue and static loads evaluation to follow, with airframe also earmarked for survivabiliry assessment on completion of test duty. Finalisation of the cockpit upgrade design occurred in FY99, with first order for remanufacture due to be placed in FY04. IOC scheduled for 2007, with peak production rate requiring 24 AH-1Ws to be upgraded annually. Initial deliveries will be to HMT-303 at Camp Pendleton, California. AH-1RO Dracula: Derivative of AH-1W for Romania, which intended to purchase initial batch of 96. Project abandoned by Bell in fourth quarter of 1999. AH-1Z King Cobra: Version for Turkey, which plans to acquire 145 attack helicopters at cost of US$4 billion; bids for initial batch of 50 (including two prototypes) submitted by end 1997. Announcement of winning contender was expected at start of 1999 but deferred to mid-2000, following delays in flight evaluations of competing types. AH-1Z selected, with announcement made at Farnborough 2000 in late July, when revealed that initial batch of 50 to be purchased at approximate US$1.5 billion cost; contract signature was due in first quarter of 2001, but was delayed because of difficulties over indigenous production of key systems such as mission computer; subsequent concerns over cost caused further delay and contract still not finalised by end of 2002, although Bell remains optimistic that sale will go ahead. Licensed production expected to be undertaken in Turkey by TAI at Ankara; current plan stipulates follow-on batches of 50 and 45 helicopters. ARH-1Z: Designation allocated to version unsuccessfully proposed for Australian Army Project Air 87 armed reconnaissance helicopter. MH-1W: In April 1998, Bell revealed a reconnaissance, armed escort and fire support ‘multimission’ version of the SuperCobra under this designation. Evolved in response to a perceived need for armed helicopters to undertake anti-drug operations, marketing efforts principally aimed at Latin American countries, with presentations to Argentina, Brazil, Chile, Colombia and Venezuela. Configuration includes a nose-mounted sighting system, with a FLIRStar Safire FLIR sensor, laser range-finder, video recorder and automatic target tracker. Proposed weaponry includes a 20mm cannon as well as 12.7mm gun pods and up to four 70mm rocket pods, but excludes anti-armour missiles and air-to-air missiles.
AH-1
Bell rolled out the first production AH-1Z Super Cobra for the US Marines on 20 November 2000. It carries a 20 mm Gatling gun with 750 rounds. An upgrade program involved converting AH-1Ws to AH-1Zs. The UH-1Y and AH-1Z feature zero-time airframes and 85% commonality, including two GE-T700 turboshafts, glass cockpits, four-blade all-composite main rotors and tail rotors, drive train, and hydraulic and electrical systems.
As of 2010, the United States Army retains 879 Cobras (models AH-1F, AH-1E, AH-1P, and AH-1S) whilst the United States Marine Corps utilizes 103 AH-1W SuperCobra models.
AH-1E / Up-gun AH-1S Formerly Enhanced Cobra Armament System or Up-gun AH-1S; with AH-1P improvements plus universal 20mm gun turret (invariably fitted with long-barrel 20mm cannon); improved wing stores management system for 70mm rockets; automatic compensation for off-axis gun firing; 10 kVA alternator for increased power. A total of 98 new build aircraft delivered 1978-79. All remaining upgraded.
AH-1F / Modernised AH-1S Fully upgraded TOW version, previously designated Modernised AH-1S; 149 manufactured for US Army in 1979-86, including 50 transferred to Army National Guard; also 378 AH-1Gs converted to full AH-1F standard between November 1979 and June 1982, including 41 TAH-1F trainers; improvements of AH-1P and AH-1E added, plus new fire-control system having laser range-finder and tracker, ballistics computer, low-airspeed sensor probe, Kaiser pilot’s head-up display, Doppler navigation system, IFF transponder, infra-red jammer above engine, hot metal and plume infra-red suppressor, closed-circuit refuelling, new secure voice communications, Kaman composite rotor blades.
AH-1G HueyCobra Original version for the US Army, powered by a single 1,044kW Avco Lycoming T53-L-13 turboshaft, derated to 820kW for T-O and maximum continuous rating. Development contract for two preproduction aircraft placed 4 April 1966, followed on 13 April by an initial order for 110 aircraft plus long-lead-time spares, deliveries of which began in June 1967. Total production, including small number of export units came to 1,127. All surviving aircraft converted to AH-1F standard.
JAH-1G HueyCobra one armament research aircraft which has been flown with the Hellfire air-launched missile, and multi-barrel cannon.
TH-1G HueyCobra Designation of dual-control trainer (all AH-1 Cobras had dual controls) conversions from AH-1G by modification to add 2 hydraulic control servos to the front seat (Instructors position) cyclic control System. This gave the instruction the ability to override the back seat Student inputs to the cycle System. The original front seat controls were arm chair type which did not provide the leverage to override the back seat controls.
AH-1J SeaCobra initial US Marine Corps version powered by a twin-turboshaft 1,342kW T400-CP-400 powerplant, a military version of the PT6T-3 Turbo Twin-Pac; this power unit incorporates two turbine engines, flat-rated to 820kW (1,100 shp) for continuous running, but with a take-off or emergency rating of 932kW (1,250shp); total of 69 delivered to USMC by early 1975 the last two being converted later as prototypes for the AH-1T, and 202 similar aircraft supplied to the Imperial Iranian Army Aviation from 1974, the US Army acting as purchasing agent. All USMC SeaCobras withdrawn.
AH-1P First batch of 100 new-production TOW Cobras (formerly called Production AH-1S), delivered 1977-78, two becoming AH-1F prototypes; improvements include flat-plate canopy, upturned exhaust, improved nap of the earth (NOE) instrument panel, continental US (CONUS) navigation equipment, radar altimeter, improved communication radios, uprated engine and transmission, push/pull anti-torque control and, from 67th aircraft onwards, Kaman composite rotor blades with tapered tips.
AH-1Q HueyCobra Interim anti-armour version for US Army, converted from AH-1G to fire Hughes TOW anti-tank missiles. Total of 92 converted; subsequently upgraded to Mod AH-1S standard.
AH-1R HueyCobra version similar to AH-1G with a more powerful T53-L-703 turboshaft engine
AH-1S HueyCobra / AH-1S(MOD) overall designation under which existing US Army AH-1 aircraft were updated to have TOW capability and incorporated other improvements, and of new production aircraft to the same or higher standard. current designations include Modified AH-1S, which covers 197 AH-1Gs and the 93 AH-1Qs with upgraded gearbox, transmission, improved rotor, T53-L-703 engine, and TOW-capability; 100 generally similar Production AH-1S, being new production aircraft with advanced avionics, instrumentation, and systems; 98 Up-Gun AH-1S, generally as the Production AH-1S but with an improved turret and weapon management systems; and the Modernised AH-1S of which 126 new production aircraft have been ordered incorporating the improvements embodied in the other AH-1S aircraft, plus advanced nav/com, avionics, and protection systems. All versions designated AH-1S until March 1987, when new-build AH-1s allotted dormant UH-1 Iroquois suffixes AH-1P, AH-1E and AH-1F. 92 AH-1Qs (early TOW-capable AH-1G) upgraded by 1979; 87 AH-1Qs upgraded in 1986-88 with Textron Lycoming T53-L-703 engines, Kaman rotor blades (see AH-1P) and TOW system, but retaining original curved canopies; total includes 15 in TH-1S Night Stalker configuration for training AH-64 crews to operate night vision system and Integrated Helmet and Display Sighting System (IHADSS). These are now known as AH-1F to avoid confusion with other variants AH-1T
AH-1T / Improved SeaCobra Generally improved version of the AH-1J for US Marine Corps, incorporating an uprated T400-WV-402 powerplant (1,469kW), the dynamic system of the Bell Model 214, and the fuselage lengthened by 1.09m; 57 built, and equipped for operation with TOW missiles. Last two AH-1Js modified as prototypes under a US Army Aviation Systems Command contract, with uprated components for significantly increased payload and performance. Incorporates features of AH-1J airframe, but embodies dynamic system of Bell Model 214, some technology developed for Bell Model 309 KingCobra, an upgraded power plant and transmission capable of transmitting the full rated engine power. Initial contract for 10 announced 23 June 1975; total of 57 built, of which 51 were subsequently modified to TOW configuration. First AH-1T flew 20 May 1976, and was delivered to US Marine Corps 15 October 1977. All have been converted to AH-1W SuperCobra standard.
AH-1W SuperCobra Bell flew AH-1T powered by two GE T700-GE-700; first flight of improved AH-1 T+, including GE T700-GE-401 engines, 16 November 1983. New USMC version with two GE T700-GE-700 engines, producing 1260kW each. Better protection and avionics are incorporated. Conversion applied to AH-1T aircraft USMC received 169 new-build examples as well as two maintenance trainers; 10 supplied to Turkey and 63 to Taiwan. Missions of AH-1W include anti-armour, escort, multiple-weapon fire support, armed reconnaissance, search and target acquisition.
Model 249 company designation of a Modernised AH-1S which was equipped and tested with an advanced four-blade main rotor as developed for the Bell Model 412
Specifications:
AH-1F Cobra Engine: 1 x Textron Lycoming T53-L-703 turboshaft, 1,800shp Main rotor: two-blade Length: 44.59ft (13.59m) Width: 44.00ft (13.41m) Height: 13.42ft (4.09m) Empty Weight: 6,598lbs (2,993kg) Maximum Take-Off Weight: 9,998lbs (4,535kg) Maximum Speed: 141mph (227kmh; 123kts) Maximum Range: 315miles (507km) Rate-of-Climb: 1,620ft/min (494m/min) Service Ceiling: 12,198ft (3,718m) HIGE: 12,200 ft Armament: 1 x General Electric nose mounted three barrel 20mm gun Accommodation: 2 Hardpoints: 4
AH-1G Huey Cobra Engine : Lycoming T53-L-13, 1381 shp Rotor dia: 44 ft 0 in (13.41 m) Length: 52 ft 11.5 in (16.14 m) Height: 13 ft 5.5 in (4.1 m) Max TO wt: 9500 lb (4309 kg) Max level speed: 219 mph (352 kph) Fuel capacity: 980 litres. Service ceiling: 12697 ft / 3870 m Range: 336 nm / 622 km Crew: 2 Armament: 2x Minigun(7,62)/GrenadeLauncher(40)], 4 St. 750kg
AH-1J SeaCobra Engine: one 1342-kW (1,800-shp) Pratt & Whitney Aircraft of Canada T400-CP-400 twin-engined turboshaft Maximum speed at sea level: 333 km/h (207 mph) Hovering ceiling in ground effect: 3795m (12,450 ft) Range with maximum fuel: 577 km (359 miles) Empty operating weight: 3294 kg (7,261 lb) Maximum take-off: 4535 kg (10,000lb) Main rotor diameter: 13.41 m (44ft ) Tail rotor diameter: 2.59m (8ft 6 in) Length rotors turning: 16.26m (53ft 4in) Height: 4.15m (13ft 8in) Main rotor disc area: 141.26 sq.m (1,520.53 sq ft) Armament: one M-197 three-barrel 20-mm cannon in undernose turret, and up to 998 kg (2,200 lb) of weapons (XM-18 Minigun pods, XM-157 seven ¬tube or XM-159 19-tube 70-mm/2.75-in rocket pods) on four underwing racks.
AH-1S Engine: 1 x Avco Lycoming T53-K-703 turboshaft, 1342kW Main rotor diameter: 13.41m No. Blades: 2 Length with rotors turning: 16.18m Fuselage length: 13.59m Width: 0.99m Height: 4.09m Empty wt: 2995 kg Max take-off weight: 4535kg Fuel cap: 1015 lt Max cruising speed with Tow misiles: 227km/h Max rate of climb: 8.22m/s Hovering ceiling, OGE: 3720m Range: 510 km Crew: 2
AH 1T SeaCobra Engine: Pratt & Whitney Aircraft of Canada T400 WV 402 twin turbine, 2,050 shp Rotor dia: 48 ft 0 in (14.63 m) Gross weight: 14,000 lb / 6350 kg Max speed: 207+ mph / 333+ kph
AH-1W SuperCobra Engines: 2 x General Electric T700-GE-401 turbo-shafts, 1,690 shp (1 260 kW) combined total of 3,250 shp (2,423 kW). Maximum speed 152 kt (282 km/h) at sea level Max cruising speed: 278km/h Initial climb rate 800 ft (244 m) per minute on one engine Service ceiling 14,000+ ft (4,270+ m) Range 395 miles (635 km) HIGE: 14,750 ft HOGE: 3000 ft Crew: 2 Empty weight: 10,200 lb (4,627 kg) Maximum take-off weight: 14,750 lb (6,691 kg) Main rotor diameter: 48 ft 0 in (14.63 m) Length overall, rotors turning: 58 ft 0 in (17.68 m) Fuselage length: 13.87m Height: 14 ft 2 in (4.32 m) Main rotor disc area: 1,809.56 sq ft (168.11 sq.m) Armament: one 20-mm multi-barrel cannon, and provision for anti-tank and anti-radar missiles, rocket launchers, and submunition dispensers.
Bell proposed the Iroquois Warrior for an interim programme which later became known as AAFSS or Army’s Advanced Aerial Fire Support System and, by December 1962, also modified an OH-13S as an armed helicopter which would combine the desired combat potential with the desired flight performance. The aircraft, known by Bell as Model 207 Sioux Scout embodied a low drag profile, crew of two seated in tandem with integrated weapons, sighting systems and equipment. A new profiled fuselage was made from a Model 47J-2 rear fuselage mated with an all-new glazed streamlined cockpit with reinforced plastic bubble. The landing gear was of the skid-type. As powerplant the Sioux Scout retained the 260hp turbo-supercharged Lycoming TVO-435-A1A and had the rotor system of the OH-13S. The crew was seated in tandem with dual flying controls. The pilot was above and behind the gunner who controlled an Emerson Electric TAT-101 chin-turret armed with two 7.62mm machine-guns. This turret was a privately-funded modified version of the M-60-C gun barbette which, linked to the movement of the gunner’s sight, could swivel 200deg in azimuth, and 15deg above and 45deg below the horizon.
The Sioux Scout also incorporated stub wings which had been designed to carry auxiliary fuel tanks as well as providing extra lift. Flight tests showed that these wings also improved high-speed turning capability. Several types of wings were evaluated on the Model 207, as well as various types of cowlings, tailboom elevators and fins.
The sole Model 207 prototype (N73927) made its maiden flight on 27 June, 1963, with Al Averill at the controls. This flight lasted ten minutes and by 25 July, the Sioux Scout had logged 18hr 30min flying. At the end of 1963, the aircraft was passed to the US Army for further evaluation by pilots of the 11th Air Assault Division at Fort Benning in Georgia. The Army pilots were surprised at the Model 207’s capabilities and asked that such an aircraft but with a more powerful engine be promptly developed.
In fact, albeit a highly promising concept, the Sioux Scout was somewhat limited in true combat capability and had no future. Only the one was built.
In June 1962, Bell invited US Army officials to Fort Worth to see the mock-up of a combat helicopter. Known as the Design D-255 “Iroquois Warrior” and wearing false s/n 62-00255 (HU-1F), the relatively small helicopter retained several features of the UH-1 and had a low silhouette, narrow profile and a small cross-section forward fuselage. This streamlined fuselage with retractable skids had been designed for maximum speed, armament payload and crew efficiency. It featured a stepped cockpit configuration with the gunner placed just in front and below the pilot. Armament included a ball-turret in the nose, a streamlined gun compartment under the fuselage and various external loads. Although innovative, the D-255 retained the powerplant as well as the basic transmission and rotor system of the UH-1C in order to reduce maintenance and development time as well as to cut costs. On 30 August, 1962, the so-called Howze Board, a study group led by Gen. Hamilton H. Howze, submitted its final report in which recommendations were made for the creation of Air Cavalry Combat Brigades and the design of specific aircraft for that purpose. Bell decided to go further in its company funded attack helicopter research programme but on a reduced cost basis. The first step was to build a flying test-bed by transforming a standard Model 47 into the Model 207 “Sioux Scout”. The flight tests were highly successful but the Army pilots called for a larger turbine-engined aircraft. Bell went to work on a redesigned scaled-down version of the D-255, known as the D-262, which was entered in the 1964 Advanced Aerial Fire Support System (AAFSS) competition calling for a fast, armoured, heavily-armed helicopter for which Lockheed (with the AH-56A Cheyenne) and Sikorsky (with the Model S-66) were eventually selected.
In 1960 the US Army launched a design competition for a new aircraft which it certified as a Light Observation Helicopter (LOH). The specification called for four seats, a 181-kg (400-Ib) payload and cruising speed of around 193 km/h (120mph). Design proposals were put forward by 12 US helicopter manufacturers from whom Bell, HilIer and Hughes were each contracted to build five prototypes for competitive evaluation. From the tests which followed, the Hughes HO-6 (later OH-6A) was selected for production as the US Army’s LOH.
Bell 206A
After losing the competition the company built a new prototype which it designated as the Model 206A JetRanger. This flew for the first time on 10 January 1966, and on 20 October 1966 this aircraft received FAA certification, after which it entered production for commercial customers, being built also by Agusta in Italy. The JetRanger was fundamentally the same as the OH-4A (formerly HO-4) prototypes, except for fuselage modifications to provide seating for five. It has been built in large numbers since 1966, and continues in production in 1989 in Canada under the designation Model 206B JetRanger III, having been the subject of progressive development and improvement programmes.
The US Army had expected to procure some 4,000 examples of the OH-6A, but became somewhat disenchanted with Hughes when the unit cost began to climb rather steeply, and the production rate to fall off. As a result, the US Army’s LOH competition was reopened in 1967 and, on 8 March 1968, Bell’s Model 206A “as announced as the winner, with production under the designation OH-58 Kiowa starting without delay; some 2,200 of these aircraft were delivered by the end of 1973. The OH-58 differs from the commercial JetRanger by having a larger-diameter main rotor, with detail changes in internal layout and the provision of military avionics. Initial deliveries to the US Army began on 23 May 1969, and within less than four months the Kiowa was deployed operationally in Vietnam.
Of the original 2,200 ordered for the US Army, 74 were withdrawn from the production line for delivery to Canada. The JetRanger was operated by the Canadian Armed Forces from December 1971 under the designation COH-58A, subsequently CH-136. An additional US Army contract for 74 aircraft was issued in January 1973 to replace those aircraft supplied to Canada.
In the early months of 1971, Bell began delivery of an improved Model 206B JetRanger II, and this subsequently replaced the Model 206A in production. It differed by having the more powerful 298-kW (400-shp) Allison 250-C20 turboshaft engine, the installation of which involved only minor airframe modification, so that it was possible also to provide kits for the upgrading of Model 206As to Model 206B standard. Australia acquired this version under the designation Model 206B-1 Kiowa, 12 being supplied by Bell and 44 produced under a co-production agreement. Commonwealth Aircraft Corporation in Australia was responsible for final assembly and only the powerplant and avionics came from the United States. Under a US Army development contract, a single OH-58A was equipped with a more powerful 313-kW (420-shp) Allison T63-A-720 turboshaft engine and an improved flat glass canopy. This modified aircraft has the designation OH-58C, and subsequently two additional OH-58A to OH-58C conversions were carried out to allow more extensive flight testing by Bell and the US Army. As a result of these tests, production modification of 275 OH-58As to a further-improved OH-58C configuration began in March 1978. Other versions include 12 OH-58Bs, similar to the OH-58A, supplied to the Austrian air force in 1976, and the US Navy has 40 TH-57A SeaRangers. These latter aircraft are dual-control trainers, which were ordered on 31 January 1968, to fulfil the requirement for a primary training helicopter for service with Naval Air Training Command at Pensacola, Florida. They are basically civil Model 206A JetRangers with US Navy avionics. The US Army Helicopter Improvement Programme (Ahip) involves the remanufacture of up to 578 OH-58A Kiowa scouts to OH-58D standard, incorporating 485kW Allison 250-C30R engines, an advanced composite four-blade main rotor, uprated transmission and tail rotor, a mast mounted sight and target designator, Stinger AAMs, CRT cockpit displays, and improved navigation and communications equipment. 23 were scheduled for delivery by the end of 1986, and conversions are being completed at a rate of five per month. Operationally, three OH-58Ds will lead five AH-64 Apaches, locating and designating targets for their Hellfire missiles. The OH-58D prototype flew in October 1983 and features a McDonnell Douglas/Northrop mastmounted sight and a Honeywell cockpit control and display sub-system. Up to 477 US Army Kiowas are planned for conversion to OH-58D standard. Powerplant is the 650 shp (485 kW) Allison 250-C30R turboshaft. Production of the JetRanger II ended in the summer of 1977, when it was replaced by the Model 206B JetRanger III. This introduced a more powerful version of the Allison turboshaft engine, offering further improvement in performance, and was the current production version in late 1981. This engine is also available as an installation kit to upgrade JetRanger Is to JetRanger III standard. The 1982 model JetRanger III included the C20J engine, in place of the C20B, an additional 14 gallon fuel tank capacity, bulge windows in the aft doors, and a lowered rear bench seat. The 206B-3 JetRanger III manufacture was transferred to Mirabel, Canada, in 1986, and also licence built in Italy by Agusta. The capability and reliability of the JetRanger family resulted in Bell developing a medium-lift version under the designation Model 206L LongRanger. The JetRanger III has skid landing gear, high-mounted tailboom and horizontal stabiliser. Two-blade teetering main rotor with preconed and underblung bearings; blades retained by grip, pitch change bearing and torsion-tension strap assembly; two-blade tail rotor; main rotor rpm 374 to 394. Hydraulic fully powered cyclic and collective controls and foot-powered tail rotor control; tailplane with highly cambered inverted aerofoil section and stall strip produces appropriate nose-up and nose-down attitude during climb and descent; optional autostabiliser, autopilot and IFR systems. Of conventional light alloy structure with two floor beams and bonded honeycomb sandwich floor, the transmission is mounted on two beams and the deck joined to the floor by three fuselage frames. The main rotor blades have extruded aluminium D-section leading-edge with honeycomb core behind, covered by bonded skin; tail rotor blades have bonded skin without honeycomb core. The aluminium alloy tubular skids are bolted to extruded cross-tubes. Tubular steel skid on ventral fin protect the tail rotor in tail-down landing. Special high skid gear (0.25m greater ground clearance) available for use in areas with high brush. Pontoons or stowed floats, capable of in-flight inflation, available as optional kits. The Rolls-Royce 250-C20J turboshaft, rated at 313kW for T-O; 276kW max continuous. Optionally, one Rolls-Royce 250-C20R/4 rated at 336kW for T-O. Transmission rating 236kW for T-O; 201kW continuous. Rupture-resistant fuel tank below and behind rear passenger seat, usable capacity 344 litres. Refuelling point on starboard side of fuselage, aft of cabin. Oil capacity 5.68 litres. The JetRanger III seats two side by side in front and three-seat rear bench. Dual controls optional. Two forward-hinged doors on each side, made of formed aluminium alloy with transparent panels (bulged on rear pair). Baggage compartment aft of rear seats, capacity 113kg, with external door on port side.
Bell 206 LongRanger
Bell 206 LongRanger
First announced on 25 September 1973, the Long Ranger was developed to meet a requirement for a turbine-powered general-purpose helicopter in a size and performance range between the five-seat Jet Ranger II and 15-seat Model 205A-1. This had the powerplant of the JetRanger III, and a fuselage lengthened by 0.63m (2ft 1in). With a capacity of 2.35cu.m, the LongRanger had good freight-carrying capability, and to simplify the loading of bulky items a double door was incorporated in the port side of the fuselage. Other improvements included the use of an advanced enlarged main rotor, plus introduction of the company’s patented Noda-Matic suspension system which gives much lower cabin vibration levels. Re¬design work included a new overhead structural beam, new transmission, and altered fuel setup. The two blade rotor system is basically the same as on the 206B, except that its di¬ameter has been extended by four feet. This actually gives the LongRanger a very slightly lower disc loading than the 206B. Also, an extruded, integral blade spar incorporating heavier elements at the tip and midsection replaces the older system by which weights were simply “tacked on” to the rotors for greater blade inertia. The original prototype Model 206L Long Ranger (N206L) flew for the first time on 11 September 1974 and production aircraft were delivered from October 1975. Accommodation provided for a pilot, co-pilot and five passengers. Alternative layouts allow for two stretchers and two ambulatory patients/attendants, or internal or external freight, or a four-seat executive seating arrangement. The LongRanger suffers by comparison in several areas, not the least of which are hovering ceilings in and out of ground effect. It gives up 4,700 feet in altitude to the 206B in HIGE and 3,800 feet in HOGE. With a capacity of 2.35cu.m (83cu.ft), the LongRanger clearly had good freight-carrying capability, and to simplify the loading of bulky items a double door was incorporated in the port side of the fuselage. Deliveries of production Long Rangers began in October 1975, but this was superseded by the Model 206L LongRanger II in mid-1978. The Model 206L-1 LongRanger II (certificated in May 1978) differs by having the more powerful Allison 250C-28B turboshaft with a maximum continuous rating of 365kW (489 shp), a higher-rated transmission, and detail improvements. Detail improvements include a redesigned aft cabin to provide 0.05m more headroom for rear seat passengers, new cowlings, firewall, engine mountings and engine deck area structure and other refinements.
The initial versions were 206L and 206L-1 LongRanger II, of which 790 built; limited production (17) of 206L-2; replaced by 206L-3 LongRanger III in 1982, of which 612 built, production having transferred to Canada in January 1987. The LongRanger IV was announced March 1992 as new current standard model; transmission uprated to absorb 365kW instead of 324kW from same engine; gross weight raised from 1,882kg to 2018kg; certified late 1992, delivered from December that year.
In Chile, Industrias Cardoen Ltda developed the C206L-III multipurpose helicopter from Bell LongRanger, featuring pilot only in cockpit behind flat-plate glazing, plus cabin accommodation. On the prototype, which was the first helicopter to be built in Chile, the classic two-pilot cabin has been replaced by a single-seat flat-plate canopy nose section, and armament is carried under fuselage hardpoints. This prototype flew in mid-1989 and had logged 100 flying hours before being flown to Fort Worth to undergo FAA certification.
Cardoen LongRanger
The TwinRanger, twin-engined version, model 206LT was built on the LongRanger IV line between 1993 and 1997. Only 13 were built. The Gemini ST twin-engined rebuild of the LongRanger III/IV was developed by Tridair and Soloy in the USA.
Over 1,700 LongRangers were produced by late 2002, including 275 LongRanger IVs and 206LTs. Customers included Air Logistics of New Iberia, Louisiana. which ordered 14 on 26 March 2003 for delivery between second quarter 2003 and 2005. Total of 12 delivered in 1999, 27 in 2000, 10 in 2001 and 12 in 2002.
Subsequently, Bell initiated develop¬ment of a multi-role military variant of the commercial LongRanger under the de¬signation Model 206L TexasRanger. Capable of rapid in the field conversion to anti-tank configuration, the seven place helicopter is capable of packing number of jettisonable armament systems – four TOW missles, 14 x 2.75in rockets in dual pods, or 2 x 7.62mm mgs. The Model 406 is a derivative of the 206 using a new four-blade rotor, a conversion of OH-58As to provide the US Army with enhanced scout helicopters under the designation OH-58D. Featuring a mast-mounted sight, these have an Allison 250-C30R engine of 485kW (650 shp) rating. The Bell 406 Combat Scout is a derivative of the OH-58D. The first conversion flew on 6 October 1983, and Bell produced 578 of these helicopters on an initial contract through to 1992. The 406CS is identical to the OH-58D except for its systems integration and the multi-purpose weapon mounts that are fitted to the Combat Scout. The Bell 406CS featured a TOW missile system, 50 calibre machine guns and 70mm rocket launchers, and a “quick change” capability enabling a helicopter to be configured to meet a multitude of different roles on the battlefield. Tactical roles require a stable observation and weapons platform, highly manoeuvrable in a nap-of-the-earth environment. Supportive roles include search and rescue, medivac and logistic support. In its standard configuration the 406CS can accommodate two litter patients or 4 passengers. It can carry 680 kgs of sling load cargo. The Bell is powered by an Allison 250-C30 engine with an electronic supervisory fuel control unit. The combination of a high power to weight ratio with a new all composite tail rotor capable of 110 shp – 220 shp transient – permitted the 406CS to be flown sideways or rearwards in speeds of up to 30 knots with complete controlability. While sharing the same basic structure as the familiar JetRanger, the incorporation of advanced technology is evident from an inspection of the 406CS. Composite, on condition, components and structures are utilised, as are elastomeric bearings. The drive shaft is a Kalflex no-maintenance unit, features that background Bell’s aim to establish a maintenance ratio of .3 hour for each hour of flight. Saudi Arabia was the first announced customer for the Model 406CS Combat Scout version of the US Army’s AHIP OH-58D. Developed for the export market, the 406CS has simplified systems, a quick-change weapon system to carry four TOW 2 anti-armour missiles or combinations of Stinger AAMs, rockets and gun pods, while retaining engine/transmission of the OH58D. The 15 Saudi machines (MH-58Ds) will be fitted with roof-mounted SaabEmerson HELITOW sighting systems instead of the mast-mounted sight. There are some AH-58D Warrior armed examples. At the end of the 1970s, the US Army set up the Army Helicopter Improvement Program (AHIP) to provide a near-term scout helicopter (NTSH) as an interim aircraft pending development of a new design (in fact the LHX). After several proposals had been examined, Bell’s Model 406 proposal was declared the winning contender in the AHIP competition and, on 21 September, 1981, the US Army announced that the Model 406 had been selected. A $151 million contract called for Bell to design, modify and test five prototype aircraft. The dynamic components were tested in March 1983 on the Model 206LM LongRanger c/n 45003 (N206N). The first of these five prototypes flew on 6 October, 1983, and was used for manual validation and training. The second and fifth prototypes were employed in flight testing at Bell’s Flight Research Center in Arlington, while the third prototype was equipped with the mast mounted sight and sent to Yuma for mission equipment package evaluation. The fourth aircraft was used for avionics and electro-magnetic compatibility.
Bell OH-5D Kiowa Warrior
Bell OH-5D Kiowa Warrior
The qualification programme was completed by June 1984 and operational tests were conducted at Yuma and Edwards in February 1985 and completed by March of the same year. The Model 406 / OH-58D incorporated a new power-plant, advanced avionics and systems as well as extended armament capabilities. Fitted with the new four-blade composite rotors developed by Bell and a mast-mounted sight, the powerplant was a 650shp Allison 250-C30R (T703-AD-700) turboshaft driving a four-blade soft-in-plane rotor, in place of the 420shp Allison T63-A-720 turboshaft driving the classic two-blade rotor of the OH-58C. The OH-58D, as it was officially designated, was equipped with a McDonnell Douglas/Northrop mast-mounted sight (MMS) capable of operating in day/night and limited visibility and with a Honeywell Sperry cockpit control and display subsystem. The MMS brings together a lot of sophisticated technology. It is a combination of television camera, thermal imaging sensor, boresight system and laser range finder/ designator. Automatically, the system focuses and tracks the area and points targets. This system provides commanders with a survivable real time combat information, command and control, reconnaissance, security, aerial observation and target acquisition/designation system to operate with attack helicopters, air-cavalry and field artillery units during day, night and reduced visibility. The MMS enhances survivability by allowing the crew to accomplish its mission while hovering behind trees and hilltops. By day, the MMS provides long-range target acquisition with television in a 2deg by 8deg field of view, and at night with thermal imaging in a 3deg by 10deg field of view. It also provides laser designation at stand-off ranges for Hellfire, M172 Copperhead and other Army and Air Force laser guided munitions (LGM). Armament of the OH-58D includes four FIM-92A Stinger air-to-air missiles, or four Hellfire air-to-surface missiles, or two rocket pods, or two 12.7mm machine-gun pods, mounted on outriggers on the cabin sides. Qualification tests for these armaments were conducted during November and December 1987. Under the AHIP programme, 578 were expected to be procured over the 1985-91 period at an estimated cost of $2.000 million. An initial batch of 171 OH-58Ds had been funded during FY88, in five lots (16, 44, 39, 36 and 36 aircraft). A further thirty-six aircraft have been requested in FY89. In 1987, deliveries totalled eighty-seven OH-58Ds among which several were of the armed version. Responding to the Army’s desire to field an initial armed helicopter, Bell modified fifteen OH-58Ds to the attack configuration known as Kiowa Warrior or simply Warrior. By July 1987, sixty-four were on the US Army inventory and the first shipment to units stationed in Europe began on 11 June, 1987, when twelve OH-58Ds were loaded on board a single Lockheed C-5A Galaxy. Deliveries of the armed version began during the spring of 1988 to the 18th Airborne Corps Brigade at Fort Bragg. The Warriors were shipped to the Persian Gulf where they were stationed to protect the vital sea lanes for the world’s oil supply. Because of the success of the Persian Gulf operation, the Secretary of the Army ordered that 243 OH-58Ds be reconfigured to the armed Warrior version. Eighty-one of these aircraft will also be equipped as the Multi-purpose Light Helicopter (MPLH), capable of carrying troops externally, litter patients or cargo on a sling. First operational deployment of the US Army OH-58Ds occurred during operation ‘Desert Storm’ when aircraft were deployed by the Aviation Battalion of the 101st Airborne Division and the 82nd Aviation Brigade of the 82nd Airborne Division. In May 1984 Bell developed the Model 406CS (Combat Scout). This increased the capability of the OH-58D and provided a quick change weapons package. Designed as a force multiplyer, the 406CS can accept any of the roof-mounted sights in production or under development, with growth provisions for laser target designation, FLIR and video thermal tracker. Bell is also under contract with the US Government for an all-composite airframe program (ACAP) which will lead to expanded use of composite materials for all Bell helicopters, including future scout helicopters. The power-plant fitted to the 406CS is the Allison 250-C30 turboshaft developing 650shp with built-in particle separation system fitted to a 510shp transmission with elastomeric vibration isolation, fail-safe four-point mounting and a thirty minute run dry capability. The first OH-58D(I) retrofit contract awarded was in January 1992. The first 117 conversions were at Amarillo, Texas, then onwards Fort Worth The US Army initially planned to modify 592 OH-58A to OH-58D, reduced to 477; reduced again to 207, but Congressionally mandated re-orders increased the total to 398 (excluding five prototypes) by 1996 from new goal of 507. Taiwan ordered 12 OH-58Ds in February 1992, plus 14 options, subsequently converted to firm orders. Deliveries started in July 1993. The programme unit cost in 1993 was US$7.46 million. Production switched to the Kiowa Warrior from the 202nd aircraft and production was completed in 2000.
The OH-58D features a four-blade Bell soft in plane rotor with carbon composites yoke, elastomeric bearings and composites blades. Transmission rating: Kiowa 339kW continuous; Kiowa Warrior 410kW continuous. Main rotor 395 rpm; tail rotor 2,381 rpm. McDonnell Douglas/Northrop mast-mounted sight containing TV and IR optics and laser designator/ranger; Honeywell integrated control of mission functions, navigation, communications, systems and maintenance functions based on large electronic primary displays for pilot and observer/gunner; hands-on cyclic and collective controls for all combat functions; airborne target handover system in all OH-58Ds operates air-to-air as well as air-to-ground using digital frequency-hopping; system indicates location and armament state of other helicopters; some OH-58Ds have real-time video downlink capable of relaying of US Army and Air Force aircraft to headquarters 40km away or, via satellite, to remote locations. Fully powered controls, including tail rotor, with four-way trim and trim release; Stability and Control Augmentation System (SCAS) using AHRS gyro signals; automatic bob-up and return to hover mode; Doppler blind hover guidance mode; co-pilot/observer’s cyclic stick can be disconnected from controls and locked centrally. The basic OH-58 structure reinforced; armament cross-tube fixed above rear cabin floor; avionics occupy rear cabin area, baggage area and nose compartment. Powered by one Allison 250-C30R (T703-Ad-700) turboshaft, (C30R/3 with improved diffuser in Kiowa Warrior) with an intermediate power rating of 485kW at S/L, ISA, FADEC. Transmission rating: Kiowa 339kW continuous; Kiowa Warrior 410kW continuous. One self-sealing crash-resistant fuel cell, capacity 424 litres located aft of the cabin area. Refuelling point on starboard side of fuselage. Oil capacity 5.7 litres. ARMAMENT: Four Stinger air-to-air or Hellfire air-to-surface missiles, or two seven-round 70mm in rocket pods, or one 12.7mm machine gun, mounted on outriggers on cabin sides; port side only for gun.
Saudi Arabia’s have 15 Bell 406 Combat Scouts with roof-mounted sights. The stealth version of the Kiowa Warrior first flew on 6 August 1990 and the US Army’s 1/17th Cavalry flies them with a laser-proof windscreen and more pointed nose.
VERSIONS OH-58D (I) Kiowa Warrior: Armed version, to which all planned OH-58Ds are being modified; integrated weapons pylons, uprated transmission and engine, lateral CG limits increased, raised gross weight, EMV protection of avionics bays, localised strengthening, RWR, IR jammer, video recorder, SINCGARS radios, laser warning receiver and tilting vertical fin, armament same as Prime Chance, integrated avionics and lightened structure. “Prime Chance” is fifteen special armed OH-58Ds modified from September 1987 under Operation Prime Chance for use against Iranian high-speed boats in Gulf; delivery started after 98 days, in December 1987; firing clearance for Stinger, Hellfire, 0.50 in gun and seven-tube rocket pods completed in seven days. Further conversion for development trials. “MultiPurpose Light Helicopter” (MPLH) involved further modification of Kiowa Warrior; features include squatting landing gear, quick-folding rotor blades, horizontal stabiliser and tilting fin to allow helicopter to be transported in cargo aircraft and flown to cover 10 minutes after unloading from C-130. Later additions include cargo hook for up to 907kg (2,000 lb) slung load and fittings for external carriage of six outward-facing troop seats or two stretchers. All Kiowa Warriors have MPLH capability. OH-58X Light Utility Variant: Contender for anticipated US Army requirement; fourth development OH-58D (69-16322) modified in 1992 with partial stealth features (including chisel nose); concept subsequently discarded.
In late 1989, overall production by Bell of members of the Model 206 family was considerably in excess of 7,000. Agusta, in Italy, has also produced JetRangers and LongRangers under licence from Bell, these being generally similar to their American counterparts.
TH-67 Creek
In 1993 the US Army took delivery of Bell 206B-3 training helicopters, designated TH-67 Creek (Bell designation TH-206), selected in March 1993 as the US Army NTH (New Training Helicopter) choice to replace UH-1 at pilot training school, Fort Rucker, Alabama (223 Aviation Regiment at Cairns AAF and 212 Aviation Regiment at Lowe AHP). Instructor and pupil sat in the front seats. The US Army initial NTH contract was for US$84.9 million. Powered by Rolls-Royce (formerly Allison) 250-C20JN engine, the first batch included nine cockpit procedures trainers outfitted by Frasca International; three configurations: VFR, IFR, and VFR with IFR provision. TH-67 features also include dual controls, crashworthy seats, five-point seat restraints, heavy-duty battery, particle separator, bleed air heater, heavy-duty skid shoes and enlarged instrument panel. IFR version additionally possesses force trim system, auxiliary electrical system and is FAA certified for dual pilot operation. The US Army initial order was for 102 in IFR configuration, and a second batch of 35 VFR helicopters were ordered February 1994. Deliveries began on 15 October 1993 with N67001 and N67014 (all TH-67s have civilian registrations). 45 aircraft (and six procedures trainer) were delivered in time for the first training course to open on 5 May 1994. Initial orders were for 137 TH-67s and nine cockpit procedures trainers; all delivered by late 1995. Additional orders were placed on behalf of the Taiwanese Army, which received 30 TH-67s in 1997-99. Deliveries in 1999 included six to the Bulgarian Air Force. A further 50 were ordered for US Army for delivery between September 2001 and November 2003.
Over 7,750 JetRangers produced by Bell and licensees, including 4,400 Bell 206Bs and 2,200 military OH-58 series; and 900 in Italy. Bell Canada delivered 28 206Bs in 1999; 14 in both 2000 and 2001; and 20 in 2002 (including 10 TH-67s).
Variation: Trident Helicopters 206 L Gemini ST Industrias Cardoen Ltda C206L-III
Specifications:
Bell 206A Engine: 1 x Allison 250-C18A, 317 shp Baggage capacity: 250 lb / 115 kg Ext sling load: 1200 lb / 545 kg Seats: 5
Bell 206B – Engine: 400 shp
Bell 206B JetRanger II Engine: Allison 250-C20, 400 hp Main rotor dia: 33 ft 4 in / 10.16 m Fuselage length: 31 ft 2 in / 9.50 m Empty weight: 1455 lb / 660 kg MTOW: 3200 lb / 1451 kg Equipped useful load: 1613 lb Payload max fuel: 1119 lb Disc loading: 3.7 lb/sq.ft Pwr loading: 8 lb/hp Max cruise SL: 118 kt / 136 mph / 219 kph Max ROC SL: 260 fpm / 384 m/min Range max fuel/payload SL: 299 nm / 345 mi / 555 km Range max fuel/payload 5000 ft/1525m: 337 nm / 388 mi / 624 km Range max fuel/ cruise: 225 nm/1.9 hr Range max fuel / range: 262 nm/ 2.2 hr Service ceiling: 13,500 ft Max range cruise: 122 kt HIGE: 11,300 ft HOGE: 5800 ft Seats: 5 Cabin length: 7 ft 0 in / 2.13 m Cabin width max: 4 ft 2 in / 1.27 m Cabin heiht max: 4 ft 3 in / 1.28 m Baggage volume: 16 cu.ft / 0.45 cu.m Max sling load: 1500 lb Fuel cap: 494 lb
206 JetRanger III Engine: Allison 250-C20B, 313-kW / 420 shp, flat-rated to 236kW (317 shp) TBO: 3500 hr Main rotor: 10.16m (33ft 4in) Main rotor disc area: 81.1sq.m / 837 sq.ft Seats: 5 Length, rotors turning 11.82m (38ft 9.5 in) Height 2.91 m (9ft 6.5 in) Max ramp weight: 3200 lb Max takeoff weight: 3200 lb / 1451 kg Standard empty weight: 1616 lb / 730kg Max useful load: 1584 lb Max landing weight: 3200 lb Max sling load: 1500 lb Disc loading: 3.7 lbs/sq.ft Power loading: 7.6 lbs/hp Max usable fuel: 517 lb Max rate of climb: 1260 fpm Service ceiling: 4115 m / 13,5000 ft Hover in ground effect: 12,800 ft Hover out of ground effect: 8800 ft Max speed: 120 kt Normal cruise @ 3000 ft: 118 kt Maximum cruising speed: 216 km/h (134 mph) at 1525m (5,000 ft) Fuel flow @ normal cruise: 187 pph Endurance @ normal cruise: 2.6 hr Range with maximum fuel and payload at 1525m (5,000ft) 608 km (378 miles) External cargo hook capacity: 680kg
Bell 206B-3 Jet Ranger III Engine : Allison 250-C20J, 414 shp / 313 kW Length : 31.168 ft / 9.5 m Height: 9.547 ft / 2.91 m Rotor diameter : 33.333 ft / 10.16 m No. Blades: 2 Fuselage length: 9.5 m Max take off weight : 3199.5 lb / 1451.0 kg Weight empty : 1636.1 lb / 742.0 kg Payload: 696 kg Fuel cap: 345 lt Max. speed : 121 kts / 225 km/h Max cruising speed : 117 kts / 216 km/h Initial climb rate : 1259.84 ft/min / 6.4 m/s Service ceiling : 13501 ft / 4115 m HIGE: 3900 m / 12,800 ft HOGE: 2680 m / 8,800 ft Range : 675 km Crew: 2 Pax: 3
Bell 206L LongRanger Engine: Allison 250 C20B, 420 shp. TBO: 1500 hrs. Main rotor dia: 37 ft. Length: 33 ft. 3 in. Height: 9 ft. 6 in. Disc loading: 3.7 lbs./sq. ft Power loading: 9.5 lbs./hp Max TO wt: 4000 lb Empty wt: 2010 lb Equipped useful load: 1932 lb Payload max fuel: 1295 lb Fuel capacity: 98 USG/588 lb Rate of climb: 1,490 fpm Service ceiling: 12,900 ft VNE: 130 knots Max cruise: 113 kt Economy cruise: 106 knots Range @ max cruise (45 min res, std tanks): 201 nm Range @ economy cruise (no res): 341 nm Duration @ max cruise (no res): 2.6 hr Hovering in ground effect: 7,300 ft Hovering out of ground effect: 2,200 ft Baggage area: 15 cu.ft Seats: 7 Max sling load: 2000 lb
Bell 206L-1 LongRanger II Engine: Allison 250-C28B, 373kW / 500 shp TBO: 1500 hr Main rotor: 37 ft / 11.28m Seats: 6/7 Length: 42.7 ft / 12.46m Height: 10.5 ft Max ramp weight: 4150 lb Max takeoff weight: 4150 lbs / 1837kg Standard empty weight: 2202 lb Max useful load: 1948 lb Max landing weight: 4150 lb Max sling load: 2000 lb Disc loading: 3.9 lbs/sq.ft. Power loading: 8.3 lbs/hp Max usable fuel: 666 lb Max rate of climb: 1320 fpm Service ceiling: 19,500 ft Hover in ground effect: 12,400 ft Hover out of ground effect: 5000 ft Max speed: 115 kt Normal cruise @ 3000 ft: 115 kt Fuel flow @ normal cruise: 228 pph Endurance @ normal cruise: 2.7 hr Range: 620km
Bell 206L-3 Engine: Allison 250-C30P, 650 hp
Bell 206L-4 LongRanger IV Engine: One 485kW / 650 shp Rolls-Royce 250-C30P turboshaft (max continuous 415kW) Transmission take-off rating: 365kW Transmission continuous rating: 276kW Optional transmission rating: 340kW Rotor dia: 11.28 m Main rotor rpm: 394 MTOW: 2020 kg Payload: 974 kg Useful load: 974 kg Max speed: 130 kt Max cruise: 115 kt Max range: 675 km HIGE (@MAUW): 10,000 ft HOGE (@MAUW): 6600 ft Service ceiling: 10,000 ft Total usable fuel: 419 lt Double doors width: 1.55m Cargo hook capacity: 907kg Crew: 2 Pax: 5 Seats: 7
OH 58 Kiowa Rotor dia: 35 ft 4 in (10.77 m) Max speed: 138 mph (222 km/h)
OH 58A Kiowa Engine: one 317 shp Allison T63 A 700 turboshaft Length: 32.28ft (9.84m) Width: 35.33ft (10.77m) Height: 9.55ft (2.91m) Maximum Speed: 122mph (196kmh; 106kts) Maximum Range: 298miles (480km) Rate-of-Climb: 1,780ft/min (543m/min) Service Ceiling: 18,999ft (5,791m) Accommodation: 1 + 4 Empty Weight: 1,583lbs (718kg) Maximum Take-Off Weight: 2,998lbs (1,360kg) Seats: 2
OH-58D Engine: 1 x Allison 250-C30R rated at 485kW / 650 shp Main rotor diameter: 10.67m No. Blades: 4 Length with rotors turning: 15.85m Fuselage length: 10.48m Height: 3.93m MTOW: 2041 kg Payload: 719 kg Empty weight: 1380kg Max speed: 230km/h Cruising speed: 204km/h Ceiling: 3660+ m HIGE: 4270 m HOGE: 3260 m ROC: 219 m/min Range: 495km Main rotor rpm: 395 Tail rotor rpm: 2,381 rpm Fuel cap: 345 lt Crew: 2 Pax: 3
TH-67 Creek Engine: 1 x Allison 250-C20J Instant pwr: 315 kW MTOW: 1450 kg Payload: 709 kg Max speed: 130 kts Max range: 675 km HIGE: 12,800 ft Crew: 2 Pax: 3
406CS Engine: Allison 250-C30 Sling load: 680 kg
TexasRanger Engine: 1 x Allison 250 Installed pwr: 375 kW Rotor dia: 11.3 m No. Blades: 2 Empty wt: 1050 kg MTOW: 1927 kg Payload: 877 kg Max speed: 210 kph ROC: 445 m/min Ceiling: 4845 m HIGE (1880kg): 4900 m HOGE (1880kg): 1585 m Fuel cap: 415 lt Range: 600 km Crew: 1 Pax: 6
206LT TwinRanger Engine: 2 x Allison 250-C20R Instant pwr: 335 kW Rotor dia: 11.28 m MTOW: 2020 kg Payload: 908 kg Max speed: 130 kts Max cruise: 110 kts Max range: 480 km HIGE (@MAUW): 10,000 ft HOGE: 6900 ft Service ceiling: 20,000 ft Crew: 2 Pax: 5 Seats: 7
