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

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.

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