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Aviation History
1955
1955 - 1442.PDF
552 FLIGHT THE AREA RULE ... the following February the Long Island firm had completed the layout for the Design 98, which has since materialized as the F11F Tiger naval fighter. This was the first aircraft designed to the area rule from the outset, and tunnel testing confirmed Grumman's hopes (and, to a large extent, the company's future): the Tiger was going to be supersonic. In October 1953, Convair also could sigh with relief: die revised F-102A was also going to be supersonic. Both companies started to build prototypes. Grumman were the first to fly. A year after the completion of tunnel testing (i.e., in August last year) the prototype Tiger smoothly flew right through the transonic regime without even using its afterburner, implying less than half die Mach 1 drag of the original F-102. Later last year, the redesigned F-102A took off from Edwards A.F.B. and went supersonic while still in the climb. Other aircraft are now using the area rule. One such is the new Chance Vought F8U Crusader, and here die application of die rule gave the Dallas engineers a very useful increment of volume around, and to the rear of, die powerplant. In this aircraft, the reduction in fuselage cross-section is not so marked as in the two other designs mentioned. Actually, it seems fair to put this down to die fact that die F8U is a more supersonic aircraft than the others, and area rule for inclined shocks comes out rather differendy from die transonic application. So far, however, the N-A.C.A. have said nothing at all 'about supersonic area rule. Nothing has been revealed about area rule for positive lift. In diis case die lift vector is inclined back, but only at half die angle of die body so mat die drag component of die lift is half what one might expect. Clearly, the area rule should be just as applicable at positive lift as for zero lift. As a final note it may be reiterated diat die rule depends upon total cross-sectional area, including tanks, rockets, gun packs or anything else which may project into die airstream. It is obviously a good procedure to nip die fuselage in a little bit more than is required by the wing alone, in order to have a little in hand for underwing stores. It might even be possible to have an aircraft with a variable cross-section in order to fly at die correct area distribution at all times. This might be done by having flexible skinning over die centre-fuselage, after die manner of some tunnel throats; more probable would be a portion— perhaps a piece of top-decking—which could be removed on sorties calling for externally attached stores. AMERICAN EXECUTIVE JET TRANSPORT THE Fairchild Engine and Airplane Corp., of Hagerstown,Maryland, have designed a "jet business transport" to cruise at 560 m.p.h. at 39,000ft with a crew of two and seven passengers on the power of four unspecified Fairchild turbojets of 1,000 lb thrust each (this figure suggests diat they would be die company's J44s). The project is called the M-225. Drawings show a low-wing monoplane with air intakes at die wing-roots, and engines mounted behind die main passenger cabin. All four jet-pipes exhaust from the rear fuselage under the sharply raked fin and rudder. Both die performance and accommodation are the most advanced so far made public and correspond in many ways to that of the projected Martin B-S7 command-transport variant. The fuselage is divided into diree compartments, the foremost of which is die crew cabin. Immediately aft is a space containing galley, baggage and equipment compartments and W.C., all grouped round an entrance vestibule to which die main entry door with integral steps gives access at a point just forward of the engine air-intakes. There are three portholes each side of the cabin immediately aft of die vestibule, corresponding to die seating layout of two rows of rearward facing seats and one semi-circular bench round the rear bulkhead. The undercarriage is tricycle and retracts inwards into die wing and forwards into the fuselage nose. No details of structure have been released, but dimensions are given as follows: span, 35 ft 4in; length, 50ft lOin; height, 13ft 3in; wheelbase, 13ft 4in; under- carriage track, 8ft 8in. The sweep angle is 35 deg and empty weight is 8,870 lb. A useful load of 8,825 lb brings the gross weight up to 17,695 lb. Fairchilds predict a "phenomenal" rate of climb of 5,160ft/min at sea level on four engines; loss of two successive engines would reduce diis in turn to 2,290 ft/min and 1,020 ft/min. Cruising at 560 m.pii. at 39,600ft die M-225 is stated to be designed for a range of 1,280 nautical miles. The wing has almost parallel chord, widi very short-span ailerons at the tips and flaps taking up the rest of the trailing edge. Air brakes are in die form of narrow spoilers rising from die wing surface immediately forward of the outboard section of the flaps. The take-off run is estimated to be 3,410ft and 5,720ft to clear a 50ft obstacle; the landing run would be 1,222ft over a 50ft barrier, with a ground run of 782ft. In addition to designing the M-225, Fairchilds claim to hold Government contracts for research into die optimum configura- tion for a naval transport aircraft for short take-offs and landings, for a high-performance naval observation aircraft and for a utility liaison aircraft for die U.S.A.F. ALUMINIUM INCREASE PLANNED THE Norwegian Ministry of Industry is considering plans forincreasing the output of aluminium at the State-owned plant at Ardal, West Norway, to 60,000 tons a year. Present produc- tion is about 24,000 tons a year. The proposed increase will require a large development of hydro-electric power, and a total investment of between £15,000,000 and £20,000,000 would be necessary. Total Norwegian aluminium output is now about 70,000 tons a year. GERMANY STARTS TO BUILD FOR the first time in ten years, aircraft construction is to beinitiated in Western Germany. The firm concerned is the well-known Dornier Company, who intend to go into production during die coming year widi die Dornier 27, a high-wing light aircraft of high efficiency. In the design of this aircraft Dornier have drawn upon die experience gained with die Dornier 25 prototype built in Spain and powered by a Tigre G-IVA of 150 h.p. (Flight, January 7di, 1955). It is expected that most production machines would have Continental or Lycoming units imported from the U.S.A. The production rrachine will have seats for five or six and a speed range from 160 m.p-h. down to as low as 30 m.p.h. Various civil and military uses are foreseen. Production is to be undertaken at die company's works in the Neuaubing suburb of Munich. Manufacture has not yet begun hut is expected to be under way by die end of die year. CANADIAN AFTERBURNING DURING the past four years, the National Aeronautical Estab-lishment at Ottawa has been engaged in a research programme aimed at improving afterburning performance. The system under investigation differs from conventional reheat systems in mat the afterburnt fuel is used to cool die turbine rotor blades, the temperature of die latter normally governing die maxi- mum combustion temperature and hence die total power output. The Canadian system makes possible an increased rate of com- bustion within die engine itself, and thus produces a twofold gain in power. Flight-testing of this system has been in progress since the beginning of the year, using a Gloster Meteor F.4 (two Rolls- Royce Derwent) loaned by the British Ministry of Supply. Dur- ing die first stage of testing, heights of over 40,000ft have been reached, and results are described as "quite satisfactory."
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