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Aviation History
1954
1954 - 1718.PDF
FLIGHT, 11 June 1954 765 AUSTER A.O.P.9 . . . and terminates in a stainless-steel firewall behind the power unit. As stated earlier, the engine is a Blackburn Cirrus Bombardier 203; this is an ungeared, unsupercharged, direct-injection, in verted four-in-line unit, which gives a rated power of 173 b.h.p. on M.T. fuel. Use of this fuel establishes a precedent, although there are indications that, in actual service, aviation petrols proper might be more readily available; with such fuels the Bombardier may shortly be cleared for powers in excess of 200 b.h.p., which should make the A.O.P.9 exceptionally lively. The engine drives a Fairey-Reed fixed-pitch lightweight steel airscrew, and is mounted on resilient-rubber bushes carried on a pair of simple tubular assemblies which are, in turn, attached to the firewall by four \m bolts. Torque is countered by off setting the engine to port and the fin to starboard. Seats and floor are almost entirely of Dufaylite honeycomb-stabilized sandwich material. (Left) Corner of a floor panel, showing reinforced corner attachment and channel edging. The neat undercarriage (right) is described in the text. Cooling air enters the port side of the nose cowling and issues from the large cut-away portion on each side of the front fuselage. Intake air enters under the cowling and passes through a special Auster-made assembly, incorporating flaps and Vokes filter elements, which is governed from a cockpit control providing for hot, cold and filtered air. (The Bombardier is not susceptible to icing, owing to the direct-injection system.) Austers also make a de-aerator for the fuel system, gravity-fed from the main tank, which ensures a continuous bulk supply of fuel upon which the injection pump can draw. The Bombardier is started by a Plessey-Coffmann cartridge starter, the breech unit of which houses six cartridges indexed and fired from the cockpit. With Kigass priming and oil dilu tion, it is stated, the engine invariably starts "on the first bang" in all climatic conditions down to — 40 deg C. The cabin-heating system will be welcomed, particularly because its capacity is, if anything, more than adequate. Air for this service is rammed in through a heat-exchanger jacketing the exhaust manifold, and is then ducted into the cabin along two flexible pipes, one of which releases air at foot level and the other demists the windscreen. The oil tank is mounted on the lower front face of the firewall, and it is connected, via an anti-surge valve, to a large cooler on the port side of the engine. Engine-driven accessories include a Plessey-supplied vacuum pump and a Rotax 24V 500W D.C. generator. The characteristics of the undercarriage assume a special import ance in an aircraft of this type, which must be able to sit down squarely in unprepared fields. Austers consider the A.O.P.9 to have the best gear yet devised for such work. The main legs arc single light-alloy forgings, braced by a short drag strut and pivoted laterally to forged lugs bolted to the fuselage, at the ends of the main shock-truss. This truss houses two Dowty Liquid Spring shock-absorbers mounted horizontally, each of which is coupled to an arm on the main leg. The wheels, the large low-pressure tyres and the single-disc hydraulic brakes are all by Goodyear, the brakes having glass- fibre shrouds to prevent collection of grass or abrasive particles. The levered-suspension tailwheel unit is also sprung with a Liquid Spring, and is fully castoring. Altogether, the perform ance of this landing gear appears outstanding. Designed to accept a rate of descent of 9 ft/sec, it is strong, light and has little drag; Ranald Porteous, the company's well-known test pilot, has found that he can "clump it down on any surface and tread on the brakes"—something which was formerly impossible owing to the rebound. The mainwheel brakes are toe-operated and the tail- wheel is steered by the rudder pedals. The fuselage is appreciably wider than that of any previous A.O.P. design (in the world, we believe) and has an outstandingly adaptable interior. The pilot sits to port, the observer is behind, near the centre-line, and the front starboard seat is for occasional passengers. Although full details have not yet been worked out, the interior will certainly be capable of being rapidly converted for use in freight, supply dropping, ambulance or casualty-evacua tion, and other roles. Between the front seats is an "airline-type" control pedestal, upon which are mounted the fuel cock, tail-trim lever, Kigass pump, engine-air control and fire extinguisher. The left side of AUSTER A.O.P.9 DATA (PROVISIONAL) Blackburn Cirrus Bombardier 203 (173 h.p. on M.T. spirit) Span, 36ft 5in; length, 23ft 8£in; height (airscrew horizontal), 7ft 2^in; wing area, 197.6 sq ft; empty weight, 1,461 lb; disposable load, 589 lb; all-up weight, 2,050 lb; wing loading, 10.4 Ib/sq ft; power loading, 11.9 Ib/b h.p.; take-off distance to 50ft under 260 yd; rate of climb (sea level), 930 ft/min; rate of climb (5,000ft), 660ft/min; time to 5,000ft, 6.4 min; normal cruising speed, 99 knots; service ceiling, 19,200ft; operational range, 214 nautical miles; ferrying range at 80 knots, 520 n.m. Note: All the above figures would be greatly improved with a more powerful Bombardier variant running on true aviation fuel. the main panel contains a full blind-flying panel (except for a rate- of-climb indicator, redundant in A.O.P. work). Also facing the pilot are engine instruments, and a Kelvin and Hughes baby com pass is mounted on the Durestos top scuttle, together with elec trical switches; below are the throttle lever, cabin-air and oil- cooler controls and the parking-brake knob. To the left is the cartridge starter pull-ring, and each door has a black-and-yellow- striped jettison lever. The starboard side of the facia is a large Durestos recess, into which fits an Army Type 62 m.f. communications set; the aerial for this well-known radio consists of a drogue-stabilized trailing wire which can be winched out some 150ft. In the rear fuselage is a remote-controlled T.R.1998 v.h.f. set, mounted on a rack above a high-capacity accumulator. This set is served by a whip aerial. An intercom mixing box can be used with either installa tion, and a press-to-speak switch is mounted on the top of the control column. Other standard fittings include variable-intensity compass and instrument lighting, camera heating, a downward-identification light, a large map pocket, stowage for six spare starter cartridges, a crowbar, a signal pistol and ammunition, and a lightweight step for refuelling. Although not currently a requirement, there seems to be no reason why other gear should not be developed, including underwing racks, spraying gear, and full dual controls. The prototype A.O.P.9 flew on March 19th, and trials have since progressed very well. Several more are in the shops, and the current Army order for production aircraft will help to keep Austers busy for a considerable time. The new aircraft has a very pleasant and distinctive sound, with which visitors to this year's Farnborough Show may be able to become acquainted. AIR SURVEY BOARD CHANGES T^HE Fairey Aviation Co., Ltd., announces changes which have * been made to the Board of its subsidiary, Air Survey Co., Ltd. Mr. C. H. Chichester Smith has retired from the chairmanship and Board to enable him to concentrate on the work of the weapon division of the parent company. G/C. F. C. V. Laws has been appointed chairman of the survey company and has been succeeded as managing director by Col. R. T. L. Rogers. Mr. C. W. Hall, a director of the parent company, has been elected as an additional director to the survey company. The Board of Air Survey Co., Ltd., now consists of G/C. F. C. V. Laws, C.B., C.B.E., F.R.P.S. (chairman); Col. R. T. L. Rogers, M.A., F.R.I.C.S., R.E. retd. (managing director); Mr. J. C. Macpherson, A.C.A.; Mr. R. Fairey; and Mr. G. W. Hall, A.F.R.Ae.S.
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