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Aviation History
1956
1956 - 0801.PDF
Installation of two D.H. Super Sprites in a Vickers Valiant (above). A mobile refuelling trolley carrying hydrogen peroxide, kerosine and nitrogen under pressure stands beside each main undercarriage leg. (Right) The Sprites in action; note the almost complete absence of smoke, • • an advantage of the liquid-propellant type of rocket motor. SPRITELY VALIANTS FIRING and dropping trials have been successfully carried outduring the past year with de Havilland Super Sprite A.T.O. rocket motors installed in a Vickers-Armstrongs Valiant, andpermission has now been given to reproduce these photographs, which for the first time illustrate the Super Sprite in its properfunctional role. The motor, with its dropping container has been developed specifically for the Valiant, and it was the first Britishliquid-propellant rocket motor to pass an official type-approval test. It is now in quantity production as the take-off aid for theValiant, and all these aircraft now entering squadron service with the Royal Air Force have provision for its installation. As a result of flight experience, production versions of the dropping containernow incorporate two stabilizing fins. These are employed to give the unit a nose-down pitching moment in the initial stages ofdropping and so prevent the risk of collision damage to the aircraft structure. Super Sprite dimensions and performance have beenknown publicly for a considerable time. Basic motor length is 117iin and diameter 20Jin. Empty weight is 620 lb, fuelled weight1,460 lb. Standard thrust is 4,200 lb for 40 seconds duration; total impulse, 120,000 lb-sec. Propellants are 57 gal hydrogen peroxideat 80 to 85 per cent concentration and 5 gal kerosine. Feed is by 3,690 cu in nitrogen initially at 2,900 to 3,100 lb/sq in. SEEING IN THE DARK AN optical amplifier that makes it possible for the human eye•**- to see in the dark—or, at any rate, in nocturnal outdoor con- ditions—has been developed by Air Research and DevelopmentCommand at the Wright Air Development Centre, Baltimore, Maryland. Known as Cat Eye, the system works on principlessimilar to those of television, though it is "approximately 1,000 times more sensitive" than a standard television camera. Thecathode-tube image is said to be clear and sharp however dark the night. The U.S.A.F. sees a use for it in night reconnaissancework and, it is claimed 3 airborne observers have been able to seethe ground clearly on a moonless winter night. Development was begun 30 months ago and the pilot modelhas been successfully flight tested. Contracts for further develop- ment and improvement have now been awarded to Westinghouseand R.C.A. In the Cat Eye equipment electro-magnetic waves (photons) aresensed and imaged on a photosensitive surface. They are trans- formed from photons to electrons, accelerated to produce electro-static images, further amplified and sensed by an electron beam and finally amplified again on a cathode-ray tube. Work has beenaimed primarily at producing a black-and-white picture, but scientists think Cat Eye could also be developed to produce colourpictures. Responsible for the new equipment are Dr. J. E. Clemens, chief of the Physics Branch, Aeronautical Research Laboratory,Wright Air Development Centre, Mr. R. H. V. Gebel, senior investigator of the project, Mr. Lake Croft and Dr. B. B. Johnstone. FLYING THE 707 (Continued from opposite page) sunshine and rain chambers, and even chambers in which ahighly combustible mixture of butane and air is held under pressure while parts are operated under working conditions atvarying temperatures. I also learned of the static tests which are a military require-ment. One military model at some time early in the production line is virtually pounded to total destruction by the application ofabnormal stresses. Another interesting section was one in which the sound level of 180db could be produced. With an eye to thefuture so-called heat barrier, many of the latest test sections were capable of producing very rapid rises in temperature. Inthe course of this tour of inspection, I also saw the vast water-test tank. For those unfamiliar with the specifications of the 707, I feelthat in justice to its advanced design I must mention, in con- clusion, some of the features which appealed to me. These are:— Airborne radar; SEL CAL; Skydrol 500 hydraulic system (with allelectrical wiring made out of Skydrol-resistant materials); anti-skid brakes; isolated power shields; isolated radio compartment; thermal(second spool) engine and wing anti-icing; electrical tail unit anti-icing; emergency air brakes; free-fall emergency gear; indication of enginereverse to each engine; high gust-criteria speeds (Vb 230 kt, Ve 350 kt); circuit-breaker within reach of pilots; separate hydraulic motors for inboard and outboard flaps; total absence of gust locks; lateral controlavailable with one flap section asymmetrical; automatic wheel-braking during retraction; dual gyrosyn compass systems; dual V.H.F., V.O.R.,A.D.F., HZ-1, etc.; inspection panels to all wheels when down; static thrust indicators; inspection panels to cargo compartments; dual cablesto all controls; hydraulic system limited to 3,000 lb/sq in; Nesa windows; underwing refuelling; rubeless tyres; two fuel booster pumpsper engine on separate circuits; Freon fire extinguishing agent; emer- gency electric flap actuation; separate indicators to each of the four mainflaps; flight engineer's panel within reach of pilots. The only omissions of importance which occurred to mewere:— Boosted rudder; central landing light; vibration indicators attachedto the engine mountings; firmer parking-brake lock; fuel heaters; larger engine instruments; space for let-down chart; crews' toilet (with up to147 passengers on board, this could be quite a problem); limited turn- ing circle; individual fresh air vents to crews' positions; hydraulic pumpsto all engines instead of inboard engines. Considering the balance between these two lists, and con-sidering how essentially simple this aircraft is to operate and fly, the conclusion remaining is that in the 707 Boeing havelaunched a product which will, I feel, make an impact upon the industry such as no aircraft has made since the DC-3 twentyyears ago.
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