Jane's Encyclopedia of Aviation

Armstrong Whitworth A.W.35 Scimitar (UK)
   Single-seat biplane fighter, the prototype of which was the converted A.W.16 and first flew on 25 June 1934. Four production aircraft were built for Norway, powered by the 540 kW (725 hp) Arm­strong Siddeley Panther XI radial engine and armed with two forward-firing Vickers machine-guns and underwing racks for light fragmentation bombs.

Flight, June 1931

SPECIAL TYPES AT THE DISPLAY

ARMSTRONG WHITWORTH AW. XVI

   THE A.W.XVI is a single-seater Fleet Fighter, with 500-h.p. Armstrong-Siddeley "Panther" engine. The machine is of all-metal construction, and it will be observed that great care has been taken to streamline everything as much as possible. For instance, the wheels are partly enclosed in "spats" to reduce their drag, and the engine is fitted with a cowling ring, which materially reduces the air resistance of the large radial air-cooled engine.
   Much research in the wind tunnel has been carried out. The A.W.XVI has a wing span of 33 ft. (10.4 m.), and the weight with full military load is 3,900 lb. (1,770 kg.). Sufficient fuel is carried for two hours' flying at full throttle, of which 1/2 hr. at sea level and 1 1/2 hr. at 15,000 ft. (4,600 m.). The landing speed is about 62 m.p.h. (100 km./h.), and the estimated maximum speed at 15.000 ft. is 200 m.p.h. (322 km./h.).

Flight, October 1931

Two New Military Aircraft

The A.W.XVI Single-Seater Fighter

   Described by the makers as "the fastest air-cooled single-seater fighter in the world," the A.W.XVI is quite noticeably a great improvement over the "Siskin" from which it originated.
   This new aircraft has been cleaned cleaner than any Armstrong-Whitworth aircraft we have seen, resulting in a machine which not only has a really fine performance, but also looks the part. The first things which catch the eye are the cleanliness of such parts as the undercarriage and tail units, while the absence of excrescences is of note. As in the Atlas II, although we imagine it is really the lessons learnt in A.W.XVI which have been applied with such good effect to the Atlas II and not vice versa, the electrical generators and navigation lights are now fitted in such a manner that they cause practically no drag at all.
   It is a single-bay biplane with steel strut interplane bracing of streamline section. The air-cooled engine, an Armstrong-Siddeley Jaguar Major, geared and supercharged, of 525 h.p., is cowled with a Townend ring fitted on flexible brackets. The fuel feed is by gravity from a tank in the fuselage having a capacity of 60 gall, and situated in the first bay behind the engine mounting. The engine bay is faired in by detachable panels, giving very easy access to such parts as the magnetos, fuel filters, oil-tank filter, etc. The first bay behind the engine is, as is usual, the one which contains the fuel tank. It also has below it the oil tank with a dome on it to obviate any possibility of oil frothing troubles in hot climates. Below this tank is the Vickers-Potts oil cooler, projecting into the slipstream underneath the machine. Abaft and above the oil tank is the mounting for the two high-pressure oxygen bottles, and abaft them again come the chutes for the used cartridges from the two Vickers guns situated in the top part of this bay and directly in front of the pilot. These guns fire straight ahead through two grooves in the decking just over the top of the engine cowling, and, being in this position, are excellently arranged to hand, for the pilot to clear a jamb should this be necessary. Behind the pilot's cockpit is the wireless equipment. This is mounted on a tray in the upper part of the tail fairway, which may slide out complete when required for adjustment or renewal.
   The fuselage is of the standard steel tube type, with tie-rod and ball-ended vertical steel strut bracing, and is faired for the most part with aluminium panels which are easily detached.
   The pilot's cockpit is large and comfortable, as befits a machine which has to be used for high-altitude fighting. It would be impossible in an article of this size to describe all the controls and fittings in this cockpit, and it must suffice to say that everything which a pilot of a single-seater fighter must have to hand is thus arranged and in a particularly convenient manner. The wheel brakes are independently operated by toe pedals pivoting around the ends of the rudder bar ; it is not necessary, therefore, to remove the feet from the bar when using the brakes. The rudder bar itself has a very simple adjustment which allows for a wide variation in pilots' leg-length, and this can be made use of in flight. The adjustable seat is controlled by a lever on the right-hand side, and is of the "push-to-raise" type. Being spring loaded - with rubber shock absorber cord - practically no force is required to put the pilot in the highest position. The undercarriage has, of course, to carry the strain of braking, and the radius rods are therefore extremely strong. They are of the built-up type with internal stiffeners, and are in the form of streamline tubes. The axle is a plain steel tube faired to a streamline shape with aluminium. The wheels are faired with "spats," which, together with strut-end fairings, give the whole undercarriage a very clean appearance. The oleo-cum-rubber compression legs are of the same type as those used on the Atlas II.
   A light bomb rack is fitted under the bottom port main plane, and this, together with the two Vickers guns, forms the total offensive armament.
   The main planes, rigged in single-bay biplane form, are of Clark YH section, and constructed throughout of steel with a fabric covering. The outer incidence bracing is rigid, being streamline steel struts in the form of a N. The ends of these struts, as also those of the interplane struts and the wing roots, are carefully faired in with aluminium fairings, giving the wing cellule a very clean form. The planes themselves have built-up steel strip spars with bulbous booms and a corrugated web. The drag bracing is of steel tubes and cross wires. The ribs are of strip steel drawn to the requisite channel or tubular section, while the covering is of doped fabric.
   The ailerons, which are Frise balanced, have a plain tube spar with similar ribs to the main planes. The leading edge is a sheet of duralumin and forms the balance. The hinge points, which are set back behind the spar, are of the ball-bearing type, and are three in number. The trailing edge of the top ailerons has a small movable flap built in it to allow of final balancing after the aircraft is rigged. Both ailerons are statically balanced by virtue of placing the hinges behind the spars, the weight of which, together with the streamline steel strut connecting the two ailerons, is sufficient to balance the trailing portion of the aileron.
   The rudder and elevators are both horn balanced, and the elevator has a metal plate attached to the horn which ensures static balance as well. The rudder has a plain tubular post with drawn strip steel ribs, and, in a similar manner to the top ailerons, has the movable flap for final balancing. The elevators are built in two pieces with the steel tube spars joined at the centre, at which point duplicate levers are attached to the operating rod.
   The tailplane is very rigid, with a spar somewhat like the main plane spars. The drag bracing is also of this spar section, and, being in the form of a Warren girder supplemented by tubes at the centre, provides a tailplane which is proof against distortion. In the A.W.XVI the nose ribs are of duralumin, but the main ribs follow the same construction as those in the wings and are of steel.
   The tail skid is more or less conventional, and is sprung with a steel coil spring of ample dimensions.
   In the air the A.W.XVI is very impressive indeed. The slow-running airscrew makes the machine particularly silent, especially when flying slowly, as she can do, and yet still be under perfect control. At high speed and at high angles of climb she shows to equal advantage, and leaves one in no doubt of her efficiency in the air. In spite of her excellent top speed and climb, her landing speed is low, and the run on landing, even without using the brakes, as short as could be wished for.

Flight, November 1932

British Aircraft

Armstrong Whitworth
Whitley Aerodrome, near Coventry

The A.W.XVI

   The A.W.XVI is a single-seater fighter fitted with Armstrong-Siddeley Panther engine. The fuselage is a tubular structure with bolted or pinned joints (no welding being used in the primary structure), and the wings have main spars of high tensile steel strip, but are, like the fuselage, covered with doped fabric.
   The undercarriage is of the through-axle type, and the wheels are enclosed in "spats" to reduce drag. The Panther engine is provided with a Townend drag-reducing ring, and altogether the A.W.XVI is remarkable for the care which has been taken in its design to reduce drag to a minimum. The result has been that the machine achieves a performance which has been claimed to be the highest of any radial engine fighter in the world.
   A petrol tank of 60 gallons (272,8 litres) is placed in the fuselage, and gives direct gravity feed to the engine.
   Main data of the Armstrong-Whitworth A.W.XVI are:
   Length o.a. 25 ft. (7,62 m.)
   Wing span (upper) 33 ft. (10,06 m.)
   Wing area 261 sq. ft. (24,25 m2)
   Gross weight 3,600 lb. (1 633 kg.)
   Military load 530 lb. (240 kg.)
  
   When the A.W.XVI is fitted with geared and supercharged Panther engine the following performances are attained :-
   Max. speed at 15,000 ft. (5 000 m.) 200 m.p.h. (322 km./b.)
   Speed at 25,000 ft. (8 000 m.) 187 m.p.h. (300 km./h.)
   Service ceiling 29,800 ft. (9 080 m.)
   Time to 20,000 ft 14-25 min.
   Time to 6 000 m 13-75 min.

Flight, November 1934

MODERN BRITISH AIRCRAFT REVIEWED

ARMSTRONG WHITWORTH

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   The "Scimitar" is a high-performance single-seater fighter, which can be fitted with the Siddeley 640 h.p. "Panther" engine or the 725 h.p. "Tiger." The machine is a single-bay unequal span biplane, and two of the features which are essential in a machine of this type have been given very particular attention: field of vision and manoeuvrability.
   In its standard form of construction, the "Scimitar" has a fuselage built of high-grade steel, and wings with main spars of high tensile steel strip. Alternatively, the fuselage can be supplied as a welded tubular structure, and the wings with spruce spars and ribs.
   An undercarriage of the "split axle" type is fitted, the semi low-pressure tyres being partly enclosed in "spats." Differentially controlled wheel brakes operated by pedals attached to the rudder bar are fitted.
   The Siddeley engine is resiliency mounted on rubber pads. It is enclosed in a new type of engine cowling, which consists of an inner and an outer ring. The inner ring embraces the cylinder heads in such a way as to restrain the air to flow through the cylinder finning. The outer ring is of the large chord type, and gives a very low air drag.
   The armament of the "Scimitar" consists of two 0.303 Vickers guns and four 20 lb. bombs under the starboard main plane.
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THE FOURTEENTH PARIS AERO SHOW

THE EXHIBITS DESCRIBED

A Fast Fighter

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   Britain's sole fighter exhibit with an air-cooled engine is the Armstrong Whitworth "Scimitar." With the Siddeley "Tiger" engine this beautifully finished aircraft has a top speed of more than 230 m.p.h. Like the other Siddeley and Avro machines, it is all-white and chromium plated, so that it cannot help but attract a large crowd throughout the Show. Those who were at the S.B.A.C. show at Hendon earlier in the year will remember (and those who were not will have read our description) that in the hands of Mr. Turner Hughes the "Scimitar" was shown as being extraordinarily manoeuvrable as well as fast.
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