An autogiro is an early type of helicopter. The first experiments with such rotorcraft began in France and Spain, with the first successful flight in 1923 in an “aircraft” invented by Juan de la Cierva. The term autogiro became a trademark of the Cierva Autogiro Company.
However, development and progress with such craft was slow and it wasn’t until the late 1930’s and after the end of the Second World War that autogiros or gyroplanes became well established.
Brothers David and Andrew Kay were partners in Kay’s Garage, Moray Street, Blackford. David Kay and his friend John Grieve designed their first of three autogiros in the late 1920’s. The first machine, Type 32/1, had a wooden fuselage and an ABC Scorpion engine. The machine was constructed by Shield’s Garage in Perth and first flew in 1932. However, it was badly damaged in a heavy landing at Leuchar’s in 1933 and not repaired.
A second and larger plane, the Type 33/1 had a four bladed propeller and a welded tubular steel fuselage. This second gyroplane was built at Eastleigh, Southampton by Oddie, Bradbury & Cull Ltd. David Kay's Gyroplane introduced the first variable incidence rotors to a rotorcraft: i.e. the angle in which the rotor approaches the oncoming airflow can be altered to suit flying conditions. See it fly at http://www.britishpathe.com/video/demonstration-of-kay-autogyro-at-southampton
The maiden flight of the Kay Type 33/1 Autogiro was described in Flight magazine in December 1934. The test pilot was Fit. Lt. A. H. C. Rawson who proved the value of the variable incidence arrangement for take off and landing. It was also mentioned in this article:
Dundee Courier. Saturday 16th March 1935
"HUSH-HUSH' TESTS OF PERTH 'PLANE Pilot Impressed by Smooth Flying Because its future is intimately linked with the municipal aerodrome project the progress of the Kay Gyroplane, designed and built by Mr David Kay, the Blackford engineer, is being watched with special interest at Perth. Last summer Mr Kay and his staff of designers left Perth and established themselves the Southampton airport at Eastleigh. Since then the gyroplane has undergone hush-hush Air Ministry tests. It transpires, however, that the machine has lately been carrying out private trials at Eastleigh. This suggests that official approval has been accorded. Trials at Eastleigh were carried out Flight-Lieutenant A. H. C. Rawson, the autogyro pilot. He flew the machine for hour, and at the conclusion of the test he expressed his pleasure the performance of the craft and mentioned the freedom from vibration in the rotor —the control of which is said to be the secret of the Kay design—and the gear, which ran very smoothly when flying. The machine seems fast from the first Lord Provost Hunter has been optimistic about arranging for the manufacture or assembly of the Kay Gyroplane at the new aerodrome, provided it becomes a commercial proposition. It is understood that the plans make provision for Kay workshops. Tenders have been invited for the constructional work at the aerodrome at Newlands, Scone, and an official who was approached yesterday said that preliminary work would start within a month."
Although Oddie, Bradbury & Cull Ltd produced two airframes that were delivered to David Kay for finishing, only one was completed. Kay Gyroplanes Limited are known to have presented technical information to Scotland Yard in the late 1930’s, following increased interest for the use of autogyros in police aviation. However, this was not pursued due to the Kay's small size and single seat specification. Intended multi-seat developments were halted by the war.
Unfortunately, insufficient capital resulted in no more experiments and the Type 33/1 machine was taken back to Scotland and put into store in Kay’s Garage at Blackford throughout the war years. This machine is now in Glasgow’s Museum of Transport. David Kay’s call up to the RAF meant he received little credit for his invention and the patent eventually ran out while he was in the Air Force and was taken up by others. The US patent application can be seen at http://www.freepatentsonline.com/2097117.html
It was shown at the Royal Aeronautical Society's garden party at Fairey Aerodrome,Harmondsworth on Sunday 8 May 1938.
A Kay Type 33/1 Gyroplane from 1934, the sole example of this type completed, is exhibited at the National Museum of Scotland, Chambers Street, Edinburgh. A video of it there is available here http://www.youtube.com/watch?v=Pypb-4HAWC8 This photograph is of it at the Transport Museum when it was situated at Albert Street, Glasgow.