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Aviation History
1934
1934 - 1374.PDF
1378 FLIGHT. DECEMBER 27, 1934. oscillation of which produces a lateral rocking motion of the head, and therefore of the complete rotor system. This motion is not at right angles to the centre lint of the machine, so that a small pitching moment is involved, and this moment serves to counteract any tendency to climb or dive during turns. A '' spectacle '' form of control wheel operates this " Z " crank for lateral control purposes. Fore and aft control is secured by a pull-and-push motion of this wheel, operating normal elevators, while direction is controlled by pedals and a rudder. Fore-and-aft trim is secured by a wheel-operated screw which gives a permanent tilt to the head. The incidence of the four blades is varied by mounting each link which secures the blade itself to the head on individual " Z " cranks. A screwed shaft runs right up through the head, operating small cranks and levers to each blade link for the rotation of these " Z " cranks. The hand control of this variable-incidence system has various safety connections which ensures that the rotor can only be run up with the blades set in the position of no lift. Briefly, the operation of the Kay Gyroplane is as follows: The rotor is run up to about 400 r.p.m. with the blades set at negative incidence, and the drive mechanism is then released. At the same time the incidence of the blades is increased to a positive degree, when it is found that the momentum of the blades, which promptly slow down to about 230 r.p.m., serves to lift the machine from the ground. Releasing the drive, of course, transfers the whole output of the engine to the tractor airscrew, and as the machine moves forward the autogyration continues, resulting in a steady climb according to the amount of control used. A great asset of this system will probably be found when high-speed tests are made, as the accentuated coning angle which the blades take up when th'eir incidence is high is naturally a serious drag-producing factor. With the Kay Gyroplane the incidence can be reduced at operational height so that the coning angle is reduced and therefore the drag, and the speed is increased. Thus it would seem that this machine embodies the same effects as a slotted, flapped, variable-area and variable-incidence fixed-wing aircraft. A further point of value in the variable incidence is the braking effect which can be LENGTH.OVERALL .......17-11 LENGTH.LESS ROTORS.... I4-K>i HEIGHT 7-8" WIDTH 15- 9' DIAMETER, ROTOR 22-0' CHORD. ROTOR BLADES .0-10 AREA.ROTOR BLADES...32 4" TARE WEIGHT (Lb) 624 ALL-UP WEIGHT (Lb! 850 KAY GYROPLANE Pobjoy "R" Engine 2 J 4 5 6 General arrangement drawings of the Kay Gyroplanein experimental and not production form. secured at the moment of landing by an increase in incidence, so that extremely gentle landings can be made. Finally, setting the incidence at a negative value immediately on landing precludes any possibility of the machine blowing over in gusty winds. There are, of course, many other points of great interest in this machine, with which we hope to deal after flying trials have been made. BUILT TO AN IDEAL The Aero Research " Snark." High Gross-Tare Weight Ratio. TO the design of Dr. N. A. de Bruyne, Aero Research,Ltd., of The Aerodrome, Newmarket Road, Cam-bridge, has constructed an interesting wooden canti- lever monoplane to seat four persons. Powered with a "Gipsy Major" engine of 130 h.p., the aircraft was flown last week for the first time by its designer, who reports that it handled well and landed at a very low speed. Bad visibility made it impossible to obtain accurate data, but the top speed appeared to be about 120 m.p.h. The "Snark," to give the machine its name of some- what cryptic derivation, was designed fcr the personal use of Dr. de Bruyne, who required an economical low- wing cantilever monoplane with folding wings in which a low wing-loading was reconciled to a good ratio of gross to tare weight. After three years of research the com- pany believes that these requirements have duly been met, as the tare weight of the "Snark " is i,i8olb., and the gross weight (which may be increased later without alteration in structure weight) is 2,2oolb. This gives a wing loading, based on full load, of 9.61b. /sq. ft. Although apparently conventional in design, the wing, which is covered with plywood, is believed by the de- signer to be the first of its type to have been stressed analytically. Within the wing, the trailing edges ot which are swept forward, are luggage compartments, situated over the C.G. of the machine, and further out- board are tanks tor thirty-two gallons cl petrol. Thus, it is claimed, the loads are well distributed. The pilot and one passenger sit over the front spar, and the remain- ing two passengers are seated over the rear spar. Differ- ential ailerons are fitted, with their operating mechanism (which embodies neither cranks nor chains) enclosed with- in the wing. The empennage is of cantilever construction. A very large amount of work has been done by the company on the stressing of plywood-covered fuselages, one of which is employed for the "Snark." Another example, incidentally, has been purchased by the Air Ministry and has passed all its tests satisfactorily. Dual controls are fitted, embodying duplicated rudder pedals and a central control column incorporating a '' flop over " device. The elevator control wires run straight from the control column to the elevators, and are entirely enclosed within the fuselage. It is possible to remove the front flooring of the cockpit to expose the control mechanism, and there is a large inspection opening behind the rear spar. Each half of the nine-foot-wide undercarriage, which is of the company's own construction, has but one moving part. Brakes are fitted, and are operated by a centrally mounted column. When the brakes are "on" the eleva- tors are automatically locked in the " up " position. (A photograph of the machine appears on page 1386.) :
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