The Beta 200 prototype (N5000F) was first flown on 26 May 1966. Filper planned several versions of the Beta with either two seats (Model 200A and 300) or four seats (Model 400A and 600A). The four-seat models had a fuselage which was stretched by 36-inches and the first Beta 400A (N5003F) was flown on 13 July 1967. The Beta 400A had a 250hp Continental IO-520. Details of the Model 600A are unknown. A former N.A. test pilot and a flight test engineer were killed in the stretched version. Registration records show that 32 Betas were completed, comprising two Model 100As, 29 Model 400As and one Model 600A, but there is some doubt as to whether all of these were completed. It is believed the company ceased operations in 1969.
Under the direction of William Orr, Filper Research designed a novel helicopter using the ‘Gyroflex Rotor’, which employed special balance weights fitted to the roots of the rotor blades instead of conventional flapping or lead-lag hinges, or other hub stability devices. Filper was in the peach-pitting machinery business. This concept was tested on the Filper Helicopter (N9712C) which had fore and aft rotor pylons and the pilot sitting astride a central beam which also carried the engine. A commercial development was the Filper Beta 100A. This was a tandem rotor machine with a two-seat cabin and pylon at the rear, and the engine with the forward pylon in front. This arrangement resulted in the pilot being unusually far from the front of the helicopter. The Beta 200 prototype (N5000F) was first flown on 26 May 1966. Filper planned several versions of the Beta with either two seats (Model 200A and 300) or four seats (Model 400A and 600A). The Beta models had various powerplants – namely the 210hp Continental IO-360-E (Model 200A), Allison 250-C18 turbine (Model 300) and 250hp Continental IO-520 (400A). Details of the Model 600A are unknown. Registration records show that 32 Betas were completed, comprising two Model 100As, 29 Model 400As and one Model 600A, but there is some doubt as to whether all of these were completed. No Filpers were ever sold to the public and never received FAA certification. It is believed the company ceased operations in 1969.
In the summer of 1935, Fiesler Chairman Gerhard Fieseler, Chief Designer Reinhold Mewes and Technical Director Erich Bachem designed a practical STOL aircraft, the Fieseler Fi 156. It was seen as fulfilling numerous roles both in civil life and for the recently resurgent Luftwaffe. The Fieseler Fi 156 Storch (Stork) was a STOL (short take-off and landing) aircraft, a three-seat extensively glazed cabin, high-winged machine with the wing liberally endowed with slats and flaps and a stalky landing gear arrangement, well suited to cushioning arrivals at unprecedentedly steep angles. The high-lift devices allowed a take¬off run of only about 60 m (200 ft) and it could land in about one-third of that distance. Fieseler’s chief designer, Reinhold Mewes, decided for ease of maintenance that the airplane should be completely conventional in its construction, and so utilized a steel tubing and fabric fuselage with wooden wings with a conventional braced tail unit and fixed tailskid landing gear. The wings were made of wood simply because they could be made in low grade factories using forced labour. The original wooden wings contained only 2 x 74 lt tanks. The engine was the then-common Argus As 10C inverted V-8 aircooled 240-hp model.
The big 46-foot wing had full-length fixed slats (projected movable slats never materialized), Fowler-type flaps that increased wing area by 18 percent, and ailerons that drooped with the flaps when they were extended past 20 degrees. The wings could be folded back along the fuselage, allowing it to be carried on a trailer or even towed slowly behind a vehicle. The long legs of the landing gear contained oil and spring shock absorbers that compressed about 450 mm (18 inches) on landing, allowing the plane to set down almost anywhere. In flight they hung down, giving the aircraft the appearance of a very long-legged, big-winged bird, hence its nickname, Storch. With its very low landing speed the Storch often landed “in place” or sometimes even backwards, if the wind was blowing strongly from directly ahead.
The Fieseler Fi 156 Storch (stork) V1 prototype was first flown during the early months of 1936. The Argus As 10C V8 engine gave the plane a top speed of only 175 km/h (109 mph), enabling the Storch to fly as slow as 50 km/h (32 mph), take off into a light wind in less than 45 m (150 ft), and land in 18 m (60 ft). In response to the prototype, in 1937 the RLM (Reichsluftfahrtministerium, Reich Aviation Ministry) put out a tender for a new Luftwaffe aircraft suitable for liaison, army co-operation – today called Forward Air Control – and medical evacuation to several companies.
V2 Prototype at the IV Internationales Flugmeeting, Zurich, 1937
Designs from from Messerschmitt (the Bf 163) and Siebel (the Si 201) and an auto gyro from Focke-Wulf (the Fw 186) based on Cierva technology were submitted, but the Fieseler entry was by far and away the most advanced in terms of STOL performance, needing a take-off run of only about 200 ft (60 m) and landing in about one-third of that distance. The first Fi 156 prototype was followed up by the second V2 prototype and then the third V3 prototype, the ski-equipped V4, plus one V5 and ten Fi 156A-0 pre-production aircraft. Flight testing of the first three prototypes (Fi 156 V1, V2 and V3) showed that the capability of this aircraft more than exceeded its STOL expectations, with little more than a light breeze blowing it could take off inonly a few feet. One of these prototypes was demonstrated publicly for the first time at an international flying meeting at the end of July 1937 in Zürich, by which time the general-purpose Fi 156A-1 was in production. The Storch repeatedly demonstrated full-load take-offs after a ground run of never more than 148 ft (45 m), and a fully controllable speed range of 32-108 mph (51-174 km/h). Service tests confirmed that Ger¬many’s armed forces had acquired a ‘go-anywhere aircraft, and for the re¬mainder of World War II the Storch was found virtually everywhere Ger¬man forces operated.
Fi-156EC2 Storch
It was immediately ordered into production by the Luftwaffe with an order for 16 planes, and the first Fi 156A-1 production aircraft entered service in mid-1937. Fieseler then offered the Fi 156B, which allowed for the retraction of the leading edge slats and had a number of minor aerodynamic cleanups, boosting the speed to 208 km/h (130 mph). The Luftwaffe didn’t consider such a small difference to be important, and Fieseler instead moved on to the main production version, the C.
The Fi 156C was essentially a “flexible” version of the A model. A small run of C-0s were followed by the C-1 three-seater liaison version, and the C-2 two-seat observation type carrying a single camera (which had a rear-mounted MG 15 machine gun for defense). Both models entered service in 1939. Some late examples of the Fi 156 C-2 were equipped to carry one stretcher for casualty evacuation.
In 1941, both were replaced by the “universal cockpit” C-3. The Fl 156C-3 was the first to be a equipped for multi-purpose use, the majority of the type being powered by the Argus As 10P engine, which was also standard in the generally similar Fi 156C-5 which had provision to carry an under fuselage camera or jettisonable fuel tank. Last of the Cs, the C-5, a C-3 with a belly hardpoint for a camera pod or drop tank. Some were fitted with skis, rather than wheels, for operations on snow.
Other versions of the Fi 156 were the C-3/Trop, which was a tropicalised version of the Fi 156C-5, and the Fi 156D which was an air ambulance version. The first two Fi 156D models were the D-0 pre-production aircraft, and the D-1 production aircraft, powered by an Argus As 10P engine.
Ten unusual pre-production aircraft were built under the designation Fi 156E-0, intended for operation from rough terrain with the standard landing gear was replaced by main units that each incorporated two wheels in tandem, the wheels of each unit, being linked by pneumatic rubber track.
A total of about 2,900 Fi 156s, mostly Cs, were produced from 1937 to 1945. When the main Fieseler plant switched to building Bf 109s in 1943, Storch production was shifted to the Mráz factory in Choceň, Czechoslovakia as the Benes-Mráz J-65 ‘Èáp’.
During the occupation of France, the Fi 156 was built by the Morane-Saulnier company at its Puteaux factory as the Morane Ms.502, and post-war as the MS.505. A lot of Luftwafe parts were collected by Morane Saulnier and reused to build the MS.500 Criquet. The wings on the original were wood but Moraine Saulnier reproduced the wings, tail and controls in metal. While heavier, the wings contained additional fuel. The original wooden wings held 2 x 74 lt tanks, and the MS wings an additional 100 lt in each wing. Moraine Saulnier used the Argus engines until supplies dried up.
A large number were also built at the captured Morane-Saulnier factory in France, starting in April 1942, as the M.S.500 Criquet.
French production models included the MS-500 (Argus As 410C), the MS-501 (Renault 6Q), and the MS-502 (Salmson 9AB). In early 1964 a re-engined version, the MS-505 with a 300 hp Jacobs R-915A began trials.
Both factories continued to produce the planes after the war for local civilian markets (in Czechoslovakia it was made as K-65 Čáp, 138 were made by 1949). Licenced production was also started in Romainia in 1943 at the ICAR (Īntreprinderea de construcţii aeronautice româneşti) factory in Bucharest. Only 10 were built by the time Romania switched sides, with a further 70 aircraft being built by the Romanians before production ended in 1946. During the war at least 60 Storchs were captured by the Allies, one becoming the personal aircraft of Field Marshal Montgomery.
A total of 2,549 Fi 156s were built.
MS.505 Criquet
Tests against fighters appeared to confirm that, at around 34 mph (55 km/h), it was a very difficult target for fighters. There was almost trouble when Udet’s camera-gun film showed not one picture of the elusive Storch. Another Fi 156A-0 was tested with three SC-50 (50 kg/110 lbs) bombs, with aim marks painted on the Plexiglas windows, while another did successful trials against a U-boat with inert 298 lbs (135 kg) depth charges. Less unexpected were supply-dropping tests and trials with smoke apparatus.
Between 1940 and 1943, Germany exported 34 Fieseler Fi 156Cs to Romania. A further Storch was assigned for Marshall Ion Antonescu’s personal use. Further Fi 156s were received in 1944 and some were probably captured after August 23, 1944, from the retreating German forces. In the so called ‘People’s Democracy’ the remaining dozens of Storchs received civilian registrations and were relegated to AVIASAN, the Romanian national air ambulance service. The last ones were finally retired in the late 1960s.
The Ilmavoimat / Maavoimat / VL Team evaluated the aircraft and carried out a series of flight tests early in 1938. As expected, the Fi 156 rated highly, with the STOL performance in particular impressing the the test team. Excerpts from the Flight Test reports written at the time reveal some of the impressions that aircraft made on the Test Pilots:
“…..nothing could possibly convey its general ungainliness. It stands so high off the ground that an average man can barely see in the side windows…”
“…..once in the cockpit, the nose didn’t even begin to block my vision because I was sitting so high above it. The cockpit area is huge, big enough to stand up in, and it’s cluttered with cranks, wheels and levers, all labeled in German. The stick and rudder are where they should be, but the rudders are big cast-aluminum footprints with safety straps of their own and the stick resembles a telephone pole. The flaps are lowered by a crank, not a dainty little crank, but a man-sized Model “T” Ford type crank that sticks out of the left wall. By winding in the Aus direction, wing-size boards flop out of the trailing edges and the ailerons race to catch up. In the spar carry-through structure over the pilot’s head is a pointer that indicates how much flap is hanging out, and in this airplane, any flap at all is a lot……”
“….. I must have made at least 15 takeoffs and landings, all of them incredibly short and none of them where I wanted them to be. On takeoff, I found that even with the correct trim, I couldn’t pull back hard enough to come even close to stalling it. As soon as I had a minimum of 35 knots, I could pull back all I wanted and do nothing but climb. I had absolutely no head-wind component and my initial climb angle was nearly 45 degrees. This airplane really will leap off the ground. Taking off three-point in a headwind, I doubt that it would need more than 20 feet to get off, although I was using close to 100 most of the time……”
“……To make short-field landings on a chosen spot, you usually like to get the airplane slow enough so you have to use power to drag it in. I was constantly frustrated in the Storch, because I never got it slow enough to need power. Almost every landing was power-off, and eventually I was so exasperated that I was approaching at 25 knots indicated. At that speed, I needed power to soften the touchdown, but it still wasn’t slow enough to hang on the prop. …… the really hot-shot German Pilot that instructed us in the Fi 156 would come creeping in over the trees at practically zero airspeed, letting it fall on command and catching it at the last moment with a burst of power…..”
“….. I tried to stall it while at altitude and found that it not only refuses to stall, but as long as I had the slightest amount of power in to give it elevator effectiveness, I could easily fly the airplane where I wanted while holding the stick all the way back. Once you master that kind of approach, you could land backwards on an outhouse roof…..”
“……I had a lot of silly things happen while flying this airplane but the silliest was when I tried slipping it. I was high, per usual, so I figured I’d just use a max deflection slip. It works on other airplanes, why not? As I leaned the aileron into it and got on the opposite rudder everything was going just fine until I got about half rudder. At that point, the rudder pressure disappeared and the rudder pedal sank to the floor with no effort from me and stayed there. So, there I was, coming down final sideways with a rudder that was stuck to the floor of its own accord. That scared the living hell out of me! I had to practically stand on the other rudder to get things straighted out. I guess the aerodynamic balance on the rudder is so big that when enough of it catches the wind, it overpowers the surface and yanks it to full deflection……”
“….Maneuvering in the Storch is a real physical workout. The controls feel the way the airplane looks—gawky and loose. The stick forces are anything but light and to keep it completely coordinated, your feet have to thrash in and out as if you were working a treadle sewing machine….”
Fieseler Fi 156 Storch in Finland
Given the low cost of the Fieseler Fi 156, this was a feasible proposition and in August 1938, the Ilmavoimat announced twenty Fi 156’s were to be bought direct from Fiesler – delivery was rapid and these aircraft were shipped and arrived before the end of the year. Additionally, a manufacturing license was bought from Fiesler and the Finnish company Veljekset Karhumäki was awarded a contract to build an initial 100 aircraft (Veljekset Karhumäki were also advised that further orders would be placed, with the objective being to ensure that all Regimental Battle Groups were fully equipped). This was a large expansion in business for Veljekset Karhumäki and two additional factory buildings were acquired, one to construct the Argus engines and one to construct the aircraft. Setup moved as rapidly as possible with production starting towards the end of 1938 and the first Finnish-manufactured Fi 156 rolling out the doors in early February 1939. Delivery averaged six Fi 156’s per month through the first half of 1939, increasing to 2 per week from July on and in the event, some 70 Fiesler Fi 156’s had been delivered by Veljekset Karhumäki by the time the Winter War broke out.
Finland entered the Winter War with some forty Fw 189 aircraft in service, in addition to the ninety odd Fieseler Fi 156 Storch’s. When the Winter War broke out, it was obvious that despite the intensive manufacturing effort over the previous six months there were nowhere near enough of the aircraft, even with the older aircraft being utilised. Despite limited numbers of observation aircraft being bought abroad and continuous production from Veljekset Karhumäki (some 10 per month by January 1940), demand for the aircraft always exceeded the supply available throughout the Winter War.
The Ilmavoimat Fi 156 production variant was a two crew (Pilot and Observer / Controller) with an enlarged loading/unloading hatch for a single stretcher so as to allow for casualty evacuation. A more powerful engine was fitted and the aircraft could carry up to three passengers in addition to the crew of two. Given that the aircraft was expected to operate from rough terrain, the standard landing gear was replaced by main units that each incorporated two wheels in tandem. For Forward Air and Artillery Control, provision was made for additional Finnish-supplied radio equipment to be installed to allow for simultaneous communication with ground units, artillery and aircraft. Mountings for 30lb phosphorus “marker” bombs were also installed and a single machinegun was fitted.
The Finnish Fieseler Fi 156 Storchs remained in service until 1960.
The Storch could be found on every front throughout the European and North African theaters of operation in World War II. It will probably always be most famous for its role in Operation Eiche, the rescue of deposed Italian dictator Benito Mussolini from a boulder-strewn mountain top near the Gran Sasso, surrounded by Italian troops on 12 September 1943. German commando Otto Skorzeny dropped with 90 paratroopers onto the peak and quickly captured it, but the problem remained of how to get back off. A Focke Achgelis Fa 223 helicopter was sent, but it broke down en route. Instead, pilot Walter Gerlach flew in a Storch, landed in 30 m (100 ft), took aboard Mussolini and Skorzeny, and took off again in under 80 m (250 ft), even though the plane was overloaded.
Fieseler Fi 156 Storch Engine : Argus 10 E/1, 175 hp Length : 32.48 ft / 9.9 m Height : 10.007 ft / 3.05 m Wingspan : 46.752 ft / 14.25 m Wing area : 279.864 sqft / 26.0 sq.m Max take off weight : 2910.6 lb / 1320.0 kg Weight empty : 1896.3 lb / 860.0 kg Payload: 837.9 lb / 380.0 kg Max. speed : 94 kts / 175 km/h Initial climb rate : 1574.80 ft/min / 8.00 m/s Service ceiling : 17388 ft / 5300 m Wing load : 10.46 lb/sq.ft / 51.0 kg/sq.m Range : 324 nm / 600 km Endurance : 5 h Crew : 1+2
Fi 156A-1
Fi.156C-2 Engine: 1 x Argus As 10C-3, 179kW (240-hp) Max take-off weight: 1325 kg / 2921 lb Empty weight: 930 kg / 2050 lb Wingspan: 14.25 m / 46 ft 9 in Length: 9.9 m / 32 ft 6 in Height: 3.05 m / 10 ft 0 in Wing area: 26 sq.m / 279.86 sq ft Maximum speed 170 kmh (109 mph) at sea level Economical cruising speed 130 km/h (81 mph) Landing speed: 25 mph Slow cruise: 31 mph Service Ceiling: 4600 m / 15100 ft Range: 385 km / 239 miles Armament: one rear-firing 7.92-mm (031-in) machine-gun on trainable mount
Fi 156D-0 –
M.S.502 Engine: 230 hp Salmson 9AB Wingspan: 46 ft 9 in Wing area: 279.7 sq,ft Length: 31 ft 8 in Height: 10 ft Empty weight: 2100 lb Loaded weight: 3140 lb Max speed: 106 mph at SL Cruise: 85 mph Service ceiling: 14,100 ft Climb to 3280 ft: 5.5 min Range: 435 mi at 72 mph
The Finnish Utu is a Standard Class single-seater that was designed and built over a three year period by a team of engineers of OY Fibera AB, a company specialising in glassfibre manufacture.
Fibera KK-1e UTU OH-368
The design team was headed by Dipl-lng Ahto Anttila, and the Utu was intended to investigate the structural applications to sailplanes of plastic laminates stabilised with polyurethane foam. The prototype, designated KK-1a, first flew on 14 August 1964, and was followed by four more prototypes, designated KK-1b, c,d and e, each with structural modifications resulting from variations in the constructional techniques used. Tests with these proved the superiority of plastics over conventional wooden construction, and the Utu in due course went into small-scale production, a total of 22 having been built when production ended early in 1970.
Fibera KK-1e Utu OH-355 / 64
The high cantilever wings have single I-spars and no ribs, each wing consisting of a polyester/glassfibre laminate sandwich shell with foam plastic core. The upper-surface hinged ailerons are of glassfibre reinforced plastic shell construction with foam plastic stiffening; there are no spoilers but flaps are fitted. The Utu has a trailing-edge split spoiler/terminal-velocity brake. One surface rotates up like a spoiler and the other splits down like a flap and the resultant air deflection from the upper spoiler drives the wing down in a strong negative lift configuration.
The fuselage is a double shell monocoque with a polyester/glassfibre laminate outer shell and a sandwich-type inner shell of similar construction to the wing. The fin is moulded integrally with the fuselage and has the tailplane mounted on top of it; the tail surfaces are glassfibre-reinforced plastic shells stiffened with foam plastic. There is a nonretractable monowheel with a drum brake, and a tail skid. The one-piece canopy is blended into the forward fuselage shape, and oxygen and radio is installed aft of the pilot’s seat.
Fibera KK-1e Utu
Fibera KK-1 Utu Wing span: 15m / 49.2ft Wing area: 11.24sq.m / 121sq.ft Length: 6.5 m / 21 ft 4 in Height: 1.22 m / 4ft 0 in Empty Weight: 200kg / 441lb Payload: 110kg / 242lb Gross Weight: 310kg / 683lb Wing Load: 27.58kg/sq.m / 5.65lb/sq.ft Water Ballast: 0kg / 0lb Aspect ratio: 20 Airfoil: NACA 63 (3)-618 root. 63(1)-612 tip Max speed (smooth air): 135 kt / 250 km/h Stalling speed: 34 kt / 63 km/h Max rough air speed: 113 kt / 210 km/h L/DMax: 35 @80 kph / 43kt / 50 mph MinSink: 0.61 m/s / 2.0 fps / 1.18 kt at 40 kt / 74 km/h No. of Seats: 1 No. Built: 22
KK-1e Span:49 ft 2.5 in Length: 21 ft 4 in Height: 4 ft 0 in Wing area: 121.6 sqft Aspect ratio: 20.0 Empty weight: 441 lb Max weight: 684 lb Max speed: 155 mph (in smooth air) Max aero-tow speed: 124 mph Min sinking speed: 2 ft/sec at 46 mph Best glide ratio: 35:1 at 50 mph
In 1959, the Societa per Azioni Fiat was awarded an Italian Defence Ministry contract to design and build a medium capacity helicopter for use by the Italian Air Force.
The Fiat 7002 is a medium-capacity dual-control helicopter for passenger transport and general-purpose duties. The main rotor is of the “cold jet” type, and is turned by ejecting compressed air, without any form of combustion, from nozzles at the blade-tips. Compressed air is provided by a Fiat 4700 turbogenerator. A small ducted tail rotor, mechanically-driven by the main rotor, ensures good manoeuvrability at low forward speeds and in autorotation.
The rotor system has a two-blade main rotor on tilting hub. Blades have leading-edge and spar of welded stainless steel sheet. Ducts in leading-edge and spar carry compressed air to propulsion nozzles at blade-tips. Blades linked together by steel strips which bear centrifugal loads and permit pitch variation. Blade chord 0.43m. Small ducted two-blade tail rotor.
The fuselage is light alloy sheet structure in three portions. Front portion accommodates side-by-side pilot’s seats; centre portion accommodates passengers or payload; rear portion carries power plant. Short semi-monocoque tail-boom carries ducted tail rotor and small horizontal stabiliser. Twin tubular-skid type.
Power is from one Fiat 4700 turbogenerator with equivalent power of 530hp housed vertically in rear of fuselage. Fuel in tanks above cabin, with total capacity of 525 litres.
Two pilots, or pilot and passenger, sit side-by-side in front portion of fuselage, with dual controls. Large sideways-opening door on each side. Centre cabin for five passengers or 2.5cu.m of freight, etc. In casualty evacuation role can carry pilot, attendant, two litters internally and two externally. Very large door on each side of main cabin.
The sole prototype flew on 26 January 1961, but development was discontinued in 1963. Fiat then designed a new high-speed three-seat helicopter, designated Fiat 7005, which had a pusher propeller mounted immediately behind the rotor pylon. This was not built and Fiat discontinued helicopter development in 1967.
Fiat 7002 Engine: Fiat 4700 turbo-compressor, 405kW Main rotor diameter: 12.0m Fuselage length: 6.12m Height: 2.88m Max take-off weight: 1400kg Empty weight: 650kg Max speed: 170km/h Cruising speed: 140km/h Ceiling: 3400m Range: 300km Crew: 2
The Fiat 4700 was an Italian turbo-generator developed by Fiat Aviazione under contract to the Italian Defence Ministry and used to power the experimental Fiat 7002 helicopter. The 4700 was a turbo-driven air compressor driven by the primary engine, a turbojet engine based on the Fiat 4002. The compressor and primary engine are mechanically independent. The engine is mounted vertically to reduce the length of the compressed-air ducts to the rotor. First run in 1960, the engine was used on the Fiat 7002 helicopter which first flew on 26 January 1961 where the Fiat 4700 was used to power the cold tip-jets on the two-blade rotor.
Applications Fiat 7002
Specification Type: Gas generator Length: 1,300 mm (51.18 in) (height) Diameter: 612 mm (24.09 in) Dry weight: 152 kg (335.10 lb) Compressor: Single-sided centrifugal flow + gas generator single sided centrifugal flow compressor driven by the free power turbine Combustors: Annular with 16 burners Turbine: 1-stage axial flow (gas trubine power) + 1-stage axial flow free power turbine (Gas generator power) Fuel type: Aviation kerosene to MIL-F-5624 (JP-4) Oil system: Re-circulating pressure system with one pressure pump and three scavenge pumps, oil grade DERD 2479. Maximum power output: 454.88 kW (610 hp) (gas hp for take-off), 376.58 kW (505 hp) (ghp max continuous) Overall pressure ratio: 4:1 Power-to-weight ratio: 2.99 kW/kg (1.82 hp/lb)
In 1954, NATO publicised the specifications for the project through the Mutual Weapon Development Programme, announcing a competition which would involve major European aerospace industries. The theme of the contest was obviously the design of a fighter intended to undertake close air support, reconnaissance and light interdiction missions, NMBR/1. Empty weight should not exceed 8 000 lbs (3,630 kg) and the fighter should be easily maintained, with high manoeuvrability and reasonable speed at low level. Fundamental to the project was the capability to operate from grass strips, semi-prepared runways and small airfields. The aim of the project was to release close air support fighters from dependence on traditional large air bases which would surely be amongst the first targets to be destroyed in any conflict. The Italian design emerged as the winner from a number of submissions and would be produced by Fiat Aviazione. It was assigned the designation G-91. An order was placed in June 1955 for three prototypes and 27 pre¬production aircraft.
The airframe low-set wings featured a 37 degrees sweepback, and swept-back tail surfaces. Conventional ailerons, elevator, rudder, and slotted flaps are fitted, and variable incidence tailplane. Two air-brakes side-by-side are fitted under the centre-fuselage. The tricycle undercarriage has single wheels on each unit. The main wheels retract inward into the fuselage and the nose wheel retracts rearward. Fuel tanks in the fuselage can be supplemented by underwing tanks.
Designed by Giuseppe Gabrielli, the first prototype flew on August 9, 1956, powered by a 1837 kg (4050 1b) st Bristol Orpheus B Or.1 turbojet. Control problems arose later during a high speed level run, and the structural failure of the tail caused the pilot to eject. After exhaustive tests on the tail unit the second prototype was fitted with a larger tailplane and a small ventral keel; the cockpit was also raised by some 63 mm (2.5 in). Powered by a 2200 kg (4850 1b) st Bristol Orpheus B Or. 3 turbojet, this aircraft flew for the first time in July 1957. It was equipped with one of the basic sets of armament: four 0.50 in (12.7 mm) Colt Browning machine¬guns, two mounted on each side below the cockpit and each having 300 rounds of ammunition. Alternative installations were two 20 mm (0.79 in) or two 30 mm (1.18 in) cannon (one each side), with 200 or 120 rounds respectively. The guns could be supplemented by two underwing packs of 25 51¬mm (2in), 15 70 mm (2.75 in) or six 127 mm (5in) rockets, or two 250 kg (551 lb) bombs.
Construction was conventional and simple. There was an all metal semimonocoque fuselage built in three sections, with an armoured cockpit fitted with a Martin Baker Mk 4 ejection seat. The nosewheel retracted rearward under the cockpit, the main undercarriage inward into a central fuselage bay. A braking parachute was fitted at the base of the rudder. The first of the preproduction G91s was flown in February 20, 1958, and in August of that year the 103O Gruppo Caccia Tattici Leggeri (Light Tactical Fighter Group) of the Italian air force was formed for operational evaluation. After limited squadron service, 16 of the preproduction aircraft were modified in 1964 for use by the Italian aerobatic team, receiving the new designation G91PAN (Pattuglia Acrobatica Nazionale).
July 1958
Two basic service versions of the original G91 were developed: the 1959 G91R single seat reconnaissance fighter and the G91T tandem two seat combat trainer/tactical fighter. Both had shortened and revised nose housings for three Vinten aerial cameras for forward and lateral oblique photography. Twenty four G91R/Is and the same number of R/IAs (with improved navigational aids) were delivered to the Aeronautica Militare Italiano, together with 50 G91R/111 fighter bombers. These models all carried the armament of four 0.50 in (12.7 mm) machine guns, as did the 101 G91T/1 trainers also delivered. It was, however, the Federal German Luftwaffe which employed the largest number of G91s, receiving 344 G91R/3s, nearly 300 of which were built in that country by Dornier, Heinkel and Messerschmitt. Fifty Italian built G91R14s and 66 Fiat/Dornier built G91T/3s, all with twin 30 mm (1.18 in) DEFA cannon, also served with the Luftwaffe. The German G91Rs (transferred later to the Portuguese air force) had two additional underwing pylons inboard, each capable of carrying 227 kg (500 lb) of stores.
The initial production variant was the G91R-1 which entered service with the Italian air force at the beginning of the 1960s, this air arm eventually acquiring over 100 similar aircraft. However, it was West Germany which proved to be the major customer, receiving a sizeable batch of Fiat-built G91R-3 aircraft plus a substantial number built under licence by a consortium comprising Dormer, Messerschmitt and Heinkel. The first German-built example of the G91R-3 made its maiden flight from Oberpfaffenhofen during July 1961, and the type entered service with Aufklärungsgeschwader 53 at Leipheim during 1962.
In 1964 West Germany cut down the intended size of its Luftwaffe because of shortages of funds and manpower. They will reduce the nine F-104G Starfighter squadrons to seven, and two Fiat G.91 reconnaissance squadrons instead of four. First line strength will be 380 F-104G’s and 170 G.91’s.
In the event, Germany’s Luftwaffe also operated some 50 or so G91R4 aircraft, originally being earmarked for equal distribution between Greece and Turkey, which eventually rejected them. After a fairly short career with the Luftwaffe, 40 of these aircraft were transferred to Portugal alongside a number of G91 R-3s made redundant when the Luftwaffe re-equipped its light attack units with DassaultBreguet/Dornier Alpha jets in the late 1970s and early 1980s.
In the spring of 1965 details were announced of the G91Y, a single seat twin jet tactical fighter bomber developed as a follow on type for the AMI. Based on the two seat G91T airframe, it incorporated two 1235/1850 kg (2722/4078 1b) st General Electric J85 GE 13A afterburning jet engines, mounted side by side in the rear fuselage and giving 60% more total thrust. Two prototypes (converted G9ITs) were flown on December 27, 1966, and September 1967, respectively. In July 1968 the first of 20 preproduction G91Ys appeared, and orders for a further 45 followed. Delivery of these was completed by mid 1976, and they are now in service with the 1O and 13O Gruppi in Italy. They have provision for JATO (jet assisted takeoff) units which can halve the distance required for takeoff, and three nose¬mounted cameras are fitted as standard. Armament comprises two 30 mm (1.18 in) DEFA cannon in the nose, and four under¬wing hardpoints for up to 1814 kg (4000 lb) of bombs, rockets or napalm canisters.
During the 1960s within the ranks of the AMI General Staff (Stato Maggiore), the idea began to emerge of a new type with higher performance than that offered by the G-91R. To avoid protracted development and coincident cost increases, Gabrielli based his design on the same aerodynamic formula as that adopted by the G-91R. Similarly, the requirements specified by the AMI were in part based on those of its predecessor and included high manoeuvrability, high subsonic speed (Mach 0.95) at low level, mechanical simplicity, high operational efficiency and the ability to operate from small fields. Payload and radius of action were greatly increased and a more complex electronic fit was embodied, although this was relatively simple to achieve since the G-91R carried only rudimentary equipment. The new aircraft would be equipped with a navigation and attack system, with a gyroscopic collimator as well as an inertial platform, which at the time constituted a useful electronics fit. Consistent with thinking of the period, no passive or active ECM package was planned. Adoption of a twin-engine formula using two general Electric J85-GE13A turbojets was planned to give the type good flight safety. Nevertheless, the configuration of the air intake system was designed in a way that later caused problems and the loss of some aircraft. The front air intake, shared by both power units, splits into a ‘y’ form near the cockpit and it was this layout which was to be the source of a number of failures. In comparison with the G-91R, the G-91Y features a 24 per cent increase in empty weight, a 73 per cent improvement in payload, a 63 per cent increase in take-off power and double the fuel load. The J85 provides 1,235 kg of ‘military’ thrust, climbing to 1,850 kg when afterburner is selected. The G-91Y was also designed to accept JATO rockets and can utilise a catapult device for take-off, something that necessitated enlargement and strengthening of certain undercarriage components. Installation of a ventral hook allows the use of arrester barriers.
G-91R
With regard to electronics, besides the normal communications equipment, the G-91Y possesses an inertial platform, a position and homing indicator (PHI), a doppler radar, an air data calculator, a radar altimeter, a radio compass and a gyroscopic calculator. Armament comprises two 30 min DEFA 552 cannon with 125 rounds each. External stores are fixed to four wing pylons, two on each side, with a maximum load 1,815 kg. The Yankee is also equipped for daylight tactical reconnaissance and carries three lateral TA-7M2 cameras and a forward-looking KA-60C camera with a rotating prism for panoramic work. All cameras are housed in the nose section. The first prototype G-91Y made its maiden flight from Turin-Caselle on 27 December 1966 and was subsequently used to explore the flight envelope. The second prototype was used for weapons trials and electronic system tests and featured modifications to the windscreen as well as the nose contours. It also had a double engine cooling air intake replacing the original, which was located at the base of the dorsal fin. The flight test programme was rapidly brought to a conclusion and in July 1968 the first production example was flown. Nevertheless, deliveries of the type to operational units only began two years later, as problems concerning the engines had first to be resolved. The first unit to receive the type was the 101st Gruppo of the 8th Stormo, which deployed temporarily to the experimental base at Pratica di Mare for transition to the new aircraft. For nearly four years, the Gruppo was the only one to operate the G-91Y and it struggled to achieve operational status and overcome the problems that construction of only two prototypes had prevented the manufacturer from solving. Later, in 1974, the 13th Gruppo of the 32nd Stormo began transition to the new type which was at last adjudged to be fully operational. In total, production of the G-91Y amounted to some 65 aircraft (MM6441-MM6495 and MM6951-MM6960), to which should be added two prototypes (NIM579 and MMS80). The final batch of eight (MM6961-MM6968) was cancelled and the last Yankee was assigned to the 32nd Stornio in 1976. In addition about 160 examples of the two-seat G91T trainer variant were also completed and this has also seen service with Italy, Portugal and West Germany. The G-91 was also evaluated by the Schweizerische Flugwaffe (Swiss Air Force) as a possible Venom replacement. In the light of Swiss interest, Aeritalia modified a production example (MM6461, c/n 2023), transforming it into the prototype ‘G-91YS’. These modifications comprised the addition of two underwing pylons capable of launching the AIM-9 Sidewinder and the replacement of the nose cameras by a Swedish-designed laser aiming system. The new nose was slightly elongated and two ventral fins were added to the two already present. Maximum takeoff weight rose from 8,700 kg to 9,000 kg, thereby increasing the take-off run by around 20 per cent. The new version was a finalist in a fly-off competition with the Vought/LTV A-7 Corsair II but negotiations were suspended and no other nation showed interest in buying the Aeritalia fighter. Principal versions – G91 (initial light attack model), G91R/1 (attack and reconnaissance model), G91R/1A (version with improved navigation system), G91R/1B (strengthened and updated version of the G91R/ 1A), G91R/3 (West German model with two 30¬mm cannon, Doppler navigation and other im¬provements), G91R/4 (G91R/3 variant with the armament of the G91R/1), G91T/1 (Italian two-seat trainer with two 0.5-in/12.7-mm machine guns), and G91T/2 (West German version of the G91T/1).
G91R Engine: 1 x Fiat-built Bristol Siddeley Orpheus 80302, 5000 lb Wingspan: 28 ft 1 in Wingarea: 176.7 sq.ft Length: 33 ft 9 in Height: 13 ft 1 in Empty weight: 6700 lb MTOW: 11,465 lb Max speed: 668 mph / M0.88 at SL Max ROC: 6000 fpm
G91R/1 Engine: one 5,000-lb (2,268-kg) thrust Fiat-built Rolls-Royce (Bristol Siddeley) Orpheus Mk 803 turbojet. Maximum speed 675 mph (1,086 km/h) at 4,920 ft (1,500 m) Initial climb rate 6,005 ft (1,830 m) per minute Service ceiling 42,980 ft (13,100 m) Radius 199 miles (320 km). Empty weight: 6,834 lb (3,100 kg) Maximum take-off weight: 12,125 lb (5,500 kg). Wing span 28 ft 1 in (8.56 m) Length 33 ft 9.5 in (10.30 m) Height 13 ft 1.5 in (4.00 m) Wing area 176.75 sq ft (16.42 sq.m). Armament: four 0.5-in (12.7-mm) machine guns / 1,500 lb (680 kg) of disposable stores.
FIAT G 91 R3 Gina Engine: Bristol Siddeley Orpheus 801, 22269 N / 2270 kp Length: 33.05 ft / 10.06 m Height: 12.992 ft / 3.96 m Wingspan: 27.986 ft / 8.53 m Max take off weight: 12502.4 lb / 5670.0 kg Max. speed: 580 kts / 1075 km/h Service ceiling: 42979 ft / 13100 m Range: 999 nm / 1850 km Crew: 1 Armament: 4MG 12,7mm 2MK 30mm Hardpoints: 4
G91T/1 Span: 8.60 m (28 ft 2.5 in) Length: 11.70 m (38 ft 4.5 in) Height: 14 ft 7.25 in / 4.45 m Gross weight: 6050 kg (13338 lb) Maximum speed: 1030 km/h (640 mph) at 5000 ft / 1525 m Service ceiling: 40,000 ft / 12190 m
G91Y Engines: two General Electric J85GE-13A turbojet, 1851 kg (4080-1b) afterburning thrust. Maximum speed 1110 km/h (690 mph) at SL Maximum speed 1038 km/h (645 mph) at 30,000 ft / 9145 m Cruise: 497 mph / 800 kph at 35,000 ft / 10670 m Initial ROC: 17,000 fpm / 5180 m/min Time to 42,000 ft / 12200m; 4 min 30 sec Service ceiling 12500 m (41,000 ft) Combat radius at sea level 600 km (372 miles) Ferry range 3500 km (2,175 miles) Empty weight 3900 kg (8,598 lb) Maximum take-off 8700 kg (19,180 lb). Wingspan 9.01 m (29 ft 6½ in) Length 11.67 m (38 ft 3½ in) Height 4.43 m (14 ft 6 in) Wing area 16.42 sq.m (176.74 sq.ft).
The first true jet aircraft built in Italy (discounting the piston¬ engined Caproni Campini N.1) was the prototype Fiat G.80, flown on a 1360 kg (3000 1b) thrust D.H. Goblin turbojet on December 10, 1951. After exhaustive flight development a batch of ten G.80 3B fighter/trainers were built in 1954 and delivered to the Aeronautica Militare Italiana. By this time the same basic tandem seat or single seat design had been developed into the G.82, with modified inlets feeding a fuselage plenum bay housing a Rolls Royce Nene RN.6 21 rated at 2450 kg (5400 lb) thrust. The basic Italian produc¬tion version was the tandem seat G.82 1B with two 12.7 mm (0.5 in) Breda SAFAT machine guns in the nose, and wing racks for two 113 kg (250 1b) bombs or eight 127 mm (5 in) rockets.
The first true jet aircraft built in Italy (discounting the piston¬ engined Caproni Campini N.1) was the prototype Fiat G.80, flown on a 1360 kg (3000 1b) thrust D.H. Goblin turbojet on December 10, 1951. After exhaustive flight development a batch of ten G.80 3B fighter/trainers were built in 1954 and delivered to the Aeronautica Militare Italiana. By this time the same basic tandem seat or single seat design had been developed into the G.82.
From the wartime G.55 fighter the Fiat company developed the postwar G.55A single seat fighter/trainer and G.55B dual trainer, both with 1310 hp Fiat RA. 1050 (licence built Daimler Benz 605) engine.
In 1948 the engine was switched to the Rolls Royce Merlin T.24 or Mk 500, rated at 1630 hp, the former being fitted to the G.59 1 and 2 and the Mk 500/20 the 3 and 4. The 4 had a lower rear fuselage to match a blister hood. In each case the suffix A denoted a single seater and B a dual two-seat version. Single seat versions could have two 20 mm (0.79 in) Hispano cannon and camera gun, and racks for two 100 kg (220 1b) bombs.
G.59-4
Production G.59s were delivered to Italy and Syria. A proposed family of true fighter derivatives with 2000 hp Packard V¬1650 11 (Merlin) engines was not proceeded with.
Among the customers were Argentina, Egypt and Syria.
All Aero 