AP 118 · No. 10 Section II · Aircraft Plate 11 / 68

Plate 11 of 68 · Between the wars · Army co-operation autogiro

Avro Rota I

Rota I, painted as K4232, the Royal Air Force Museum’s Avro 671 Rota I, the RAF’s licence-built Cierva C.30A autogiro, delivered to the School of Army Co-operation at Old Sarum in August 1934, recalled in 1940 to calibrate the Chain Home radar stations and flown with No. 529 Squadron, then SE-AZB in Sweden after the war until the RAF Museum bought it back in 1978, with its 140 hp Armstrong Siddeley Genet Major radial: overall aluminium dope, Type A blue, white and red roundels on the fuselage sides with black ‘K4232’ aft of them, plain aluminium three-blade rotor folded at rest on its pylon, black cylinders and exhaust collector ring and a bare metal two-blade propeller with red tips, as displayed at Hendon.

3D model

Turn it over

A procedural model built in Blender from published dimensions, drawings and photographs, painted as K4232, the Royal Air Force Museum’s Avro 671 Rota I, the RAF’s licence-built Cierva C.30A autogiro, delivered to the School of Army Co-operation at Old Sarum in August 1934, recalled in 1940 to calibrate the Chain Home radar stations and flown with No. 529 Squadron, then SE-AZB in Sweden after the war until the RAF Museum bought it back in 1978, with its 140 hp Armstrong Siddeley Genet Major radial: overall aluminium dope, Type A blue, white and red roundels on the fuselage sides with black ‘K4232’ aft of them, plain aluminium three-blade rotor folded at rest on its pylon, black cylinders and exhaust collector ring and a bare metal two-blade propeller with red tips, as displayed at Hendon. Drag to orbit, scroll or pinch to zoom · download .glb (562 KB)

Data plate

Specification

First flight, number built and top speed are for the whole family (); engine, crew and dimensions are for the Rota I modelled here.

History

The Rota I

The Spanish engineer Juan de la Cierva invented the autogiro to make an aeroplane that could not stall. Its rotor was not driven by the engine: once the machine was moving, air flowing up through the blades kept them turning, and they went on lifting it at speeds at which a wing would have quit. His C.4 made the first successful autogiro flight at Getafe in January 1923, and in 1926 he moved his work to Britain and formed the Cierva Autogiro Company. His early types still carried stub wings, ailerons and a rudder. The C.30, which first flew in April 1933, did away with all of them: the pilot steered by tilting the whole rotor head with a control column that hung down from it, and the fuselage carried only a fixed tailplane and fins.

The C.30 became by far the most numerous autogiro built before the war. A. V. Roe built the production C.30A under licence at Manchester as the Avro 671 Rota, with a 140 hp Armstrong Siddeley Genet Major radial, and Lioré-et-Olivier in France and Focke-Wulf in Germany built more; sources put the total at around 150. It could take off in a short run and land almost on the spot, though it could not hover or rise vertically, and private owners, flying clubs, police forces and air arms across Europe bought it. Cierva himself did not see the helicopter overtake his idea: he was killed when a KLM airliner crashed on take-off at Croydon in December 1936.

The Air Ministry ordered ten Rotas, K4230 to K4239, in 1934, and the School of Army Co-operation at Old Sarum tried them as artillery spotters and liaison aircraft until they were withdrawn in 1938. The war gave them a second, secret job. The Chain Home radar stations had to be calibrated, and an autogiro could circle slowly over a fixed point at a known range and height as no aeroplane could. From 1940 the surviving Rotas and impressed civilian C.30As flew with calibration flights around the coast, and in June 1943 these became No. 529 Squadron, the only RAF squadron to fly autogiros, which disbanded in October 1945. Two RAF Rotas survive in Britain: K4232 at the RAF Museum in London and HM580 at IWM Duxford.

This airframe

Rota I K4232

K4232The airframe modelled

K4232 is one of the ten Rotas built by Avro at Manchester for the RAF, and it was delivered to the School of Army Co-operation at Old Sarum, Wiltshire, on 25 August 1934. It flew with No. 2 Squadron at Hawkinge and on trials at Martlesham Heath before returning to Old Sarum, and in September 1938 it went into store at Cowley with 88 hours in its log. In 1940 it was brought back for radar calibration, flying first with No. 5 Radio Maintenance Unit at Duxford and then with the calibration flights that became No. 529 Squadron in 1943. After the war it was sold to Sweden, where it flew as SE-AZB and was used by SAAB at Linköping as a test aircraft until 1967. The RAF Museum bought it back and took it to Cardington for restoration in June 1978, and it has been displayed at Hendon since 1981. The model shows it as displayed in its pre-war markings: overall aluminium dope, Type A blue, white and red roundels on the fuselage sides with black “K4232” aft of them, the plain aluminium three-blade rotor folded at rest on its pylon, the black cylinders and exhaust collector ring of its Genet Major, and a bare metal two-blade propeller with red tips.

See it at Royal Air Force Museum London

Where to see one

In the gazetteer

The gazetteer records the Rota I in 3 UK collections. The airframe modelled here is marked.

Every airframe and serial All 68 plates

Profiles and models are procedural interpretations built in Blender from published dimensions, three-view drawings and photographs of each airframe. Treat the museum aircraft as the reference.