|Skeeter AOP.12 of the Central Flying School of the Royal Air Force|
|First flight||8 October 1948 (Cierva W.14)|
|Primary users||British Army
Royal Air Force
The Saunders-Roe Skeeter was a two-seat training and scout helicopter produced by Saunders-Roe ("Saro") of Cowes and Southampton, in the United Kingdom. The Skeeter has the distinction of being the first helicopter to be used by the British Army Air Corps.
Design and development
In 1947 the Cierva Autogiro Company began work on the Cierva W.14 Skeeter, a small two-seat helicopter suitable for both civil use and as a military observation aircraft. The Skeeter was a single-engined helicopter of conventional configuration, with a 29 foot (8.84 metre) three-bladed main rotor and a three-bladed anti-torque rotor mounted at the end of a triangular section tailboom. The crew of two sat in a glazed cabin, with the engine, a 110 hp Jameson FF-1 air cooled horizontally opposed piston engine, mounted behind the crew and under the main rotor. A fixed tricycle undercarriage was fitted.
The first prototype Skeeter made its maiden flight at Eastleigh airfield on 10 October 1948. The helicopter proved to be underpowered, and the experimental Jameson engine was prone to overheating, so it was decided to develop a Mark 2 Skeeter, to be fitted with the well established de Havilland Gipsy Major 10, giving 145 hp (108 kW). The Mark 2 was a larger aircraft had a different appearance.
The Skeeter 2 first flew on 15 November 1949, but it soon became apparent that it suffered from severe ground resonance problems that Cierva struggled to resolve, causing it to be destroyed during ground testing on 26 June 1950. Despite these problems, Cierva received an order from the Ministry of Supply for three improved Skeeters, (two Mark 3 and one Mark 4) for evaluation by the Royal Air Force and Royal Navy. These three aircraft were not completed before Saunders-Roe took over the Cierva's facilities and development programmes in January 1951. In 1953 the Bombardier-engined Mark 3B was passed to the Aeroplane and Armament Experimental Establishment. Testing showed that these aircraft remained underpowered and that the ground resonance problems had not been resolved, causing official interest to be suspended with Saunders-Roe undertaking a long series of company funded tested to identify the causes and to identify solutions to the problems.
The solution involved a redesigned undercarriage and revised blade friction dampers on the rotor head. This allowed Saunders-Roe to finally demonstrate that the ground resonance problems had been fixed when the Skeeter Mark 5 was tested by the A&AEE in March 1954. This re-ignited official interest in the Skeeter, with an order for four Skeeter Mark 6s with 200 hp (149 kW) Gipsy Major 200 engines (designated AOP.10 and T.11 by the British armed forces) for evaluation, and finally production orders for 64 AOP.12s, with a 215 hp (160 kW) engine, were placed from 1956, with deliveries starting in 1958.
The British Army ordered 64 Skeeter 6's, to be designated as the Skeeter AOP.12 (Air Observation Platform), and the Skeeter finally entered service in October 1956. Several Skeeter AOP.12s were operated by the Central Flying School of the Royal Air Force. With the merger of the helicopter activities of the British Bristol Aeroplane Company, Fairey and Saro with Westland Aircraft in 1960, plans to develop a turbine powered version were abandoned – although this knowledge was used in the development of the Westland Scout and Westland Wasp through to the P.531 which was based on the Skeeter airframe.
- Cierva W.14 Skeeter 1
- Original design, first flown on 8 October 1948, powered by a Jameson 106 hp FF-1 engine. It had a triangular cross section to its tail boom. Only one was built.
- Cierva W.14 Skeeter 2
- First flew in 1949. Powered by 145 hp Gipsy engine. Suffered badly from ground resonance and eventually shook itself apart. This version had a circular-section tail boom, as did all future versions. Only one was built.
- Skeeter 3
- Also with De Havilland Gipsy engine. Mark 3B powered by 180 hp Blackburn Cirrus Bombardier engine.
- Two were produced. No orders were placed by the British Army.
- Skeeter 4
- Version for the Royal Navy, was rejected. Similar to Skeeter 2 and 3. Only one was produced. Built at same time as Mark 3B.
- Skeeter 5
- Similar to other earlier Skeeters. Only one was produced.
- Skeeter 6
- Three prototypes were procured. One was the Mark 5 rebuilt with the Gipsy Major 201 fuel-injection engine for gaining Certificate of Airworthiness.
- Skeeter AOP.10
- Three pre-production evaluation aircraft built for the British Army
- Skeeter T.11
- One dual-control trainer was built for the Royal Air Force
- Skeeter 7
- Had 215 hp Gipsy Major 150 engine. This was the most successful Skeeter. 64 were built and acquired by the British Army Air Corps.
- Skeeter AOP.12
- Air Observation Platform helicopter for the British Army Air Corps and training helicopter for the Royal Air Force.
- Skeeter T.13
- Training version for the RAF. The Skeeter T.13s were used to train army helicopter instructors.
- Skeeter Series 8
- Commercial version similar to Skeeter 7, with Gipsy Major 215 hp. Only single example completed, with two more abandoned incomplete.
- Skeeter Mk.50
- Export version of the Skeeter 7 for the German Army Aviation Corps. Six were ordered and exported.
- Skeeter Mk.51
- Export version of the Skeeter 7 for the German Navy. Four were ordered and exported.
- Portuguese Air Force
Six Skeeter Mk.50 and four Skeeter Mk.51 acquired from the German Army Aviation Corps and German Navy, respectively. These non-airworthy examples were delivered in July of 1961 and were stored at OGMA; due to lacking spare parts their rebuilt was eventually cancelled and they were sold.
There is one remaining flying example of the Skeeter though a number are held by British museums, including the Museum of Army Flying.
Another, in Army Air Corps colours is on static display in the aeronautics hall of the Science Museum, London. This example is easily viewed and photographed from the raised observation deck in the hall.
Specifications (Skeeter AOP.12)
Data from Saunders and Saro Aircraft since 1917
- Crew: Two
- Length: 26 ft 8 in (8.12 m)
- Rotor diameter: 32 ft 0 in (9.75 m)
- Height: 9 ft 6 in (2.89 m)
- Disc area: 804 ft² (74.7 m²)
- Empty weight: 1,656 lb (751 kg)
- Max. takeoff weight: 2,200 lb (998 kg)
- Powerplant: 1 × de Havilland Gipsy Major 215 4-cylinder aircooled inverted engine, 215 hp (160 kW)
- Maximum speed: 109 mph (95 knots, 175 km/h)
- Cruise speed: 106 mph (92 knots, 171 km/h)
- Range: 260 mi (226 nmi, 418 km)
- Endurance: 3 hr
- Service ceiling: 12,800 ft (3,901 m)
- Rate of climb: 1,150 ft/min (5.8 m/s)
- Related lists
- London 1988, pp. 237, 239.
- Flight 21 October 1948, pp. 477–478.
- London 1988, p. 239.
- flight 1956 p355
- London Air Enthusiast 1994, p. 3.
- Cierva's financial backer withdrew from helicopter development after the fatal crash of the Cierva Air Horse in mid-1950
- London 1988, pp. 239–242.
- Flight 30 March 1956, p. 355.
- London 1988, pp. 245–249.
- London Air Enthusiast 1994, pp. 4–5.
- Flight 1956 p355
- Flight 1956 p355
- Until the formation of the Army Air Corps in 1957, the AOP squadrons were operated by the RAF
- London 1988, p. 246.
- London 1988, p. 252.
- "Ferreira, Rui. Esquadra 552 Zangões - Em perigos e Guerras Esforçados" (in Portuguese). Wakarounds. 21 January 2011. Retrieved 2 March 2013.
- London 1988, pp. 253–254.
- "Cierva Skeeter Flies". Flight, 21 October 1948, pp. 477–478.
- London, Peter. "Last of the Line: The Saro Skeeter". Air Enthusiast, No. 54, Summer 1994. ISSN 0143-5450. pp. 2–5.
- London, Peter. Saunders and Saro Aircraft since 1917. London: Putnam, 1988. ISBN 0-85177-814-3.
- "Saunders-Roe Skeeter: Development and Construction of the Mark Six". Flight, 30 March 1956. pp. 355–359, 374.
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