Flight, June 1936

ANOTHER NEW LIGHTWEIGHT
Refined Design and Equipment a Feature of the Luton Buzzard

   INTEREST in the design of a new ultra-light monoplane, the Luton Buzzard, is heightened by the fact that its designer is Capt. C. H. Latimer-Needham, who was responsible for the design of the successful Halton light aeroplanes some ten years ago. He also designed the first British sailplane, the Albatross, in 1930. Capt. Needham is well known as a pioneer in the British light aeroplane and gliding movement, and was, in fact, the first in this country to qualify for the international soaring pilot's certificate.
   The makers are Luton Aircraft, Ltd., Luton Aerodrome, Barton, Bedfordshire, and the test flying is being done by F/O. K. G. Stodart, who will be remembered as a competitor in the Melbourne Race.
   The Buzzard has been produced as a single-seater light aeroplane of low initial cost with small running and upkeep expenses, and which can be housed with the minimum of hangar space. No effort has been spared in the attempt to obtain the highest aerodynamic efficiency practicable, such refinements being included as split-flap gear, trousered landing wheels and wing-root fillets.
   A low-wing pusher monoplane, it has a span of 40ft., with 147 sq. ft. of wing surface and an aspect ratio of 10.9. The centre portion of the wing, of 7 1/2 ft. span, is built integral with the fuselage, and to this the outer sections attach by three bolts each. Dismantling and assembly are a matter of seconds, and when dismantled the aeroplane may be stored in a space 7 1/2 ft. by 20ft.

Constructional Details

   The fuselage, of clean aerodynamic design, is oval in section throughout its length and decreases in depth at the rear to accommodate the pusher airscrew. The engine is mounted behind the pilot's head fairing, an arrangement which relieves the pilot of noise and at the same time keeps the line of thrust relatively low.
   The construction is carried out in spruce and plywood, on sailplane lines The wing has a single main box spar, with plywood torsion-resisting nose and a light secondary spar. The wing has a parallel chord over the central, 15ft. beyond which there is a pronounced taper to the tips. Ailerons run the entire length of the tapered portion. Two short struts, one on each side, connect the wing at the junction to the fuselage top, apart from which the wing is cantilever.
   Split flaps are provided along the centre portion of the wing for steepening the gliding angle and reducing the already low landing speed. Specially manufactured Dunlop air-wheels, 17.13m. x 7.43m., are attached to the centre section wing by short cantilever supports, the whole being trousered. The wheels are 5ft. apart, thus providing a wide track giving safety in landing and ease of taxying.
   The five-gallon fuel tank, sufficient for a four-hour flight, is housed inside the fuselage and well clear of the engine, but is easily accessible.
   The makers state that the Buzzard has been designed with the exceptional speed range of from 25 m.p.h. to 90 m.p.h., and cruises at 80 m.p.h. The take-off is accomplished after a run of a very few yards.
   Normally the Anzani 54 h.p. vee-twin engine is fitted, but alternative units, such as the 34 h.p. Scott Flying Squirrel and 25.4 h.p. Douglas Sprite, are available. Instruments fitted as standard are airspeed indicator, cross level, small aero compass and engine revolution indicator. The provisional price is L325.
   The Buzzard was due to make its first public demonstration yesterday.

Flight, August 1936

A BUZZARD in its ELEMENT
Flying the Latest Ultra-Lightweight: Sailplane Characteristics of the Luton Buzzard: The Pleasant Pusher
By H. A. TAYLOR

   FEW people who have had any experience of the pusher type of aeroplane will deny its charm, and this type has always appeared to me to be particularly suitable for the use of the private pilot who flies for pleasure alone. He or she, of course, is the pilot to whom the lately revived ultra-light machine is most likely to appeal, for few of these machines are designed to have the performance demanded for serious long-distance travelling.
   In the new Luton Buzzard (described in Flight of June 18) Capt. Latimer-Needham has endeavoured to provide a machine with the pleasant features of the pusher yet possessing a performance which would enable it to be used for serious cross-country work in reasonable weather. With his experience in the design and construction of sailplanes, it might be expected that his latest creation would embody those features of the sailplane which make for air-borne efficiency, and the Buzzard is clean enough, for instance, to necessitate the use of split flaps in order to steepen the glide and reduce the period of natural float while holding-off. It is worth noting, however, that, with a landing speed below 30 m.p.h., a mild tendency to float is of small importance even when fields are being used, and flaps in this case can still be looked upon as pleasant luxuries which enable the pilot to stretch or shorten the glide at will.
   The wooden structure of the Buzzard is simple, the engine is accessible and - of greater importance to the prospective owner - the outer sections of the semi-cantilever wing may be quickly removed, leaving an actual storage width of 7 1/2 ft.
   For preliminary flying experience with such a machine the conditions at the little Barton aerodrome were far from ideal. Though an almost entire lack of wind allowed one to use the longest run, the grass was so long that this lack of wind proved to be a distinct handicap. Naturally enough, the grass both spoilt the acceleration and reduced the available lift at the critical speed. Before entering the machine I had, in fact, practically made up my mind to content myself with a few full-throttle runs, and then to await a more suitable day. Although F/O. Stodart had already taken the machine round and cleared the tall hedge - even with the flaps accidentally left in the down position - I did not feel that one with no previous experience of the best acceleration attitude would clear this hedge with quite the margin necessary for safety. However, after two preliminary runs - the second of which provided a short flight of 1907 dimensions - the machine was eased off the ground with eighty yards or so to spare.

In the Air

   Immediately the machine was air-borne I realised just how much better the take-off could be with a reasonably smooth and well-mown runway. Flown off tarmac, even in a flat calm, I doubt if the run would be much more than a hundred yards, and the climb is quite good enough to enable one to clear any fairly placed obstacles. It appeared that an airspeed of 50 m.p.h. provided the most effective rate of climb, though this would vary, of course, according to the state of the air and the heat of the day.
   With no previous experience of sailplanes I expected to have some little trouble with accurate fore-and-aft control in a machine fitted with an all-movable tailplane. In fact, after one preliminary "straight," I had no difficulty in keeping the attitude steady either on the ground or in the air; all that was required was a constant and gentle forward pressure on the stick. Nevertheless, later machines will be modified for the benefit of any ham-fisted purchasers. During the actual takeoff I made the mistake of attempting to hoist it into the air on the strength of an apparently adequate indicated air-speed and succeeded only in losing a little hard-won speed; five more seconds of tail-up acceleration would have done the trick, and only the fear that the machine was never going to unstick in the long grass caused me to disregard instinct and pin my faith on an A.S.I. - which might have been showing anything from 25 to 40 m.p.h. with its swinging needle. With a little more space no newcomer will have any qualms about the take-off. The rudder control is adequate throughout and not so sensitive as to cause over-correction when "aiming" along a short nose. In the air the controls are, I imagine, typical of the sailplane, with light and effective directional and fore-and-aft controls, but with somewhat stodgy ailerons - stodgy, that is, to the pilot who is more accustomed to small-span machines providing a 100-m.p.h. draught over these surfaces. However, one hardly uses them, since the Buzzard will turn accurately almost on rudder alone and is particularly stable laterally.
   That the airscrew fitted to the prototype machine is of too fine a pitch was suggested by the fact that, even on the ground, the Anzani twin would reach 3,500 r.p.m. - 500 r.p.m. more than the speed for which the airscrew was designed. The maximum speed, consequently, was below normal, and I obtained about 75 m.p.h. on full throttle without loss of height; at 3,000 r.p.m. the speed was as high as 65 m.p.h., even though the machine was flying on less than half-throttle. This engine, too, was fitted with a manually operated ignition control, but later examples will probably have automatic ignition, a throttle control of sensible proportions, and at least one magneto of the impulse starter type. With a rigid engine mounting it is not, perhaps, unusual that vibration should be noticeable on the ground at certain speeds, but almost non-existent while in the air. A distinct advantage of the pusher type is that the exhaust crackle from the stub pipes should not be particularly obvious while in the air - though neither helmet nor goggles' was necessary or worn. Grass seeds from the interior of the cockpit proved to be the source of the only minor discomfort experienced! It is really very pleasant to fly with the engine and the slipstream behind and with an almost complete hemisphere of forward view. Only in this way can one see the world.
   Unexpectedly enough, with a comparatively high thrust line, the Buzzard glides, engine off, at about 50 m.p.h. with no obvious elevator load in either, direction; one might have expected it to demand forward pressure, since this is necessary to a small degree in powered flight. I brought it in at a speed a little below 50 m.p.h., though 40 m.p.h. is ample, even with the flaps down. These, incidentally, are operated directly by means of a horizontally placed lever on the left, and some six or seven different positions can be used.

The First Approach

   After a short period of gliding with the flaps up in order to obtain some idea of the way in which a glide can, when necessary, be stretched, I put them down with enough height to spare (in my own estimation) to permit a little crab side-slipping. In fact, none was really necessary, though a mild slip was held sufficiently long to discover that such approach adjustment could be made without difficulty, and I should say that the glide, with flaps down, is of the order of 8 to 1 - sufficiently steep to please anyone. The pilot can always raise the flaps in a second if undershooting is suspected, and different speeds will always give different approach angles.
   Forgetting that the Buzzard's ground angle is very slight, my landing was of a mildly tail-first variety. No difficulty was experienced in checking the glide without pump-handling, and at the moment of stall the stick was eased right back; unfortunately the elevator was still powerful enough to increase the incidence, and the tail skid perched half a second before the undercarriage. I should imagine that the machine is better landed on sailplane lines - that is, flown gently on to the ground. Once the wheels have touched at less than 30 m.p.h. all way should have been damped out and the landing run, in any case, is a matter of a few yards. This type of landing, within reasonable speed limits, should be much simpler for the novice than the much-vaunted three-pointer which is necessary with the more normal type of machine. Furthermore, as the tail cannot then be depressed beyond a very small limit, no ballooning will result from a gentle wheeler.

LUTON BUZZARD
Specification with Anzani Engine.

   Weight (including equipment) 600 lb.
   Disposable load 200 lb.
   Length overall 20 ft.
   Span 40 ft.
   Span (wings detached) 7 1/2 ft.
   Height 5 1/2 ft.
   Maximum speed 85 m.p.h.
   Cruising speed 75 m.p.h.
   Endurance 4 hours.
   Stalling speed 25 m.p.h.
   Initial climb 450 ft./min.
   Price ?325
   Makers: Luton Aircraft, Ltd., Barton-in-the-Clay, Beds.