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Aviation History
1956
1956 - 1785.PDF
21 December 1956 949 The only photograph to be released for publication emphasizes the superb view available from the cock- pit (which has a Martin- Baker seat). At the foot of the page is a diagram clarifying the arrangement of control jets and show- ing the probable engine installation. Possible alter- native engine arrange- ments are also indicated. SHORT SCI TODAY the aircraft designer has more than one way of com-bating the trend towards overworked wings. The gas turbinehas opened up methods by which lift may be generated directly, merely by pointing the jet from a turbojet unit down-wards. Lift from such a mechanism stays constant as long as the turbojet continues to run, and is unaffected by whether the aircraftis moving forwards, backwards or sideways. Rolls-Royce put the idea into practice as long ago as 1954, with their thrust-measuringrig which will always be known as the "Flying Bedstead." Neither of the two Rolls-Royce flying rigs so far constructed isreally to be regarded as a flying machine in the normal sense of the term. Nevertheless, their successful solution of the problemsof stability and control has encouraged the Ministry of Supply to sponsor the development of an ad hoc aircraft embodying theprinciple of vertical lift. The contract was placed with Short Brothers and Harland, Ltd., of Belfast. It specified that thecompany should develop and build one research aeroplane capable of: vertical take-off using jet lift; transition to forward flight; andnormal forward translational flight supported by the lift generated by its wing (and, of course, the reverse sequence). First news of the placing of the contract was given by thethen newly appointed Minister of Supply, Mr. Reginald Maudiing, in November last year. At that time no details of the project weregiven, apart from the fact that the aircraft would be designated P.D.I 1. The machine now bears the company designationShort SC.l, and it began its taxying trials at the end of last week. Most of the essential features of this singularly interesting—and quite unique—aeroplane may be discerned from the photo- graph and from our provisional drawings. The basic airframe isa simple stressed-skin structure, presenting few unusual problems and reflecting the company's policy of making their one-off experi-mental and research vehicles as straightforward as possible—a policy emphasized by the somewhat similar SB.5.The wing is a true delta with a typical high-subsonic form. Sheer speed was not a requirement and the undercarriage is, infact, not retractable. Nevertheless the design of the main and nose gears is of considerable technical merit, since it meets unusualrequirements—such as vertical descent and other conditions other- wise peculiar to helicopters. The length of the hydraulic shock-struts is self-evident; and it is pertinent to remark that, before he came to Shorts, Mr. Hugh Conway, the chief engineer, was withBritish Messier and with Dunlop. Overall direction for the SC.l design was the responsibility of Mr. David Keith-Lucas, thetechnical director. Power is provided by five Rolls-Royce R.B.108 turbojets. Nodetails of these units may be published but they are clearly small Britain's Unique V.T.O. Research Aircraft engines of high specific thrust, generally similar to the R.B.82Soar. One of the R.B.108s is apparently mounted fairly conven- tionally, fed from a dorsal intake and exhausting at the rear toprovide forward propulsion. The other four are likely to be arranged as shown in the inset diagram. At take-off it is probable that all five engines will be running,the lifting quartet being opened up to full thrust to take the machine off the ground. Control at zero, or low, forward speedmust be provided by a system of air jets so disposed that they are capable of exerting suitable pitching or rolling moments aboutthe e.g. of the aircraft. Such air jets can be seen in the picture and our artist has indicated their position in his sketch. As therearward-facing engine is not needed for propulsion at this stage it is logical to use it as the source of compressed air for such jets. At a suitable height the pilot can begin the transition processwhich converts the aircraft from hovering flight—poised on its four lift jets like a fountain-ball in a shooting gallery—to normalcruising flight supported by its wing. A means has to be devised for closing down the four stabilizing air jets and transferringcontrol functions entirely to the rudder and wing surfaces. At the same time the propulsive engine must be made to give increasingforward thrust, while the lift jets are throttled back progressively as the lift from the wing builds up. All the complex control andauto-stabilizer systems have been developed by Shorts, working in conjunction with the R.A.E., Farnborough. The company dosuch work at their three-year-old Castlereagh plant, where over 1,000 people are now employed in the Precision Engineering Divi-sion (which is also a major missile contractor and the biggest- selling analogue computer organization in Europe). Flight Trials are being handled by Tom Brooke-Smith, the chieftest pilot. Now completely back in harness and fully recovered from his serious accident a few years ago, he has prepared himselfwell for the task of mastering his curious charge. Earlier this year he obtained a full helicopter endorsement and he has lately beenat Hucknall flying the Rolls-Royce Bedsteads. He has likened the latter experience to "learning to ride a bicycle over again." Taxying trials have already proceeded well in the first stage ofproving the character of the SC.l. Rear Admiral Sir Matthew Slattery, chairman of Short and Harland, recently said, "Ournext task will be to prove the SC.l as a conventional aircraft, testing it in forward flight and using normal take-off technique.We shall then proceed step-by-step to the ultimate objective, which is unrestricted take-off and landing and transition fromhovering to forward flight." Of the initial programme, a sub- stantial proportion will comprise hovering trials with the machinetethered to a special gantry on the airfield at Belfast.
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