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Aviation History
1952
1952 - 0541.PDF
FLIGHT, 29 February 1952 247 POWER STEERING R.Ae.S. Members, at Hull, Discuss the Paper by Hancock and Person WHEN a main R.Ae.S. lecture, Power Steering for Aircraft (summarized in our last week's issue) was delivered before the Brough Branch in Hull on Thursday evening, February 21st, the authors, Messrs. K. G. Hancock and P. Person, each read sections, and answered numerous questions arising during the lively discussion. Mr. George Dowty was in the chair. MR. H. G. CONWAY (British Messier) opened the discussion. He had hoped to hear more about pilot controls for steering—a separate steering wheel, a control coupled to the aileron wheel, or perhaps in some aircraft one coupled to the rudder. Foot- operated steering de-clutched for flight and re-engaged on landing could cause some difficult moments during change-over. Regard ing shimmy damping, he felt that the coupled-wheel system was the best, i.e. stop the shimmy on the ground. He did not believe shimmy could occur with coupled wheels, although the whole nosewheel structure might oscillate. He referred also to the one- tyre-deflated case, about which the lecturers had said a good deal. This was an emergency case and might be accepted as such, and if shimmy did occur it was unfortunate but not disastrous. In fact, in practice after first touch-down the one wheel ran along a few degrees yawed. In reply to Mr. Conway, the lecturers said that they had seen a film indicating clearly that shimmy could occur with coupled wheels. Coupled wheels placed a limit on the maximum steering torque which could be employed. The one-tyre-deflated case was mandatory and thus had to be provided for. MR. A. E. ELLISON (English Electric) was suspicious of hydraulic anti-shimmy systems, and agreed with Mr. Conway that coupled wheels were the correct solution. He spoke of the importance of sensitivity in hand-steering. This was specially necessary at high speed on the runway. At low speeds it was not so important because there was time to apply judgment. In answer, it was mentioned that caster axis friction would help to guard against shimmy if hydraulic damping failed. MR. R. CUSSONS (Dowty) commented on the size of motor needed in relationship to the one-tyre-deflated case. Referring to the table of comparison of gross steering torques (printed last week) amplification of which was requested, the authors said that the first three aircraft concerned were early types and their figures today were regarded as low. Another questioner (Blackburn and General Aircraft) thought that troubles of the one-tyre-deflated case could be forgotten if pneumatic nosewheel tyres could be abandoned. The lecturers answered that they did not think that the pneumatic cornering qualities could yet be reproduced with solid tyres. Other speakers said that early problems were those brought by Award to Dr. Roxbee Cox T HE Institution of Mechanical Engineers has awarded the James Clayton Prize for 1951, amounting to £1,550, to Dr. H. Roxbee Cox, Ph.D., D.I.C., B.Sc.(Eng.), M.I.Mech.E., F.R.Ae.S., "for his contributions to engineering science and practice, par ticularly in the fields of aeronautics, power generation and fuel utilization, communicated in part in a Thomas Hawksley lecture to the Institution in November, 1951." The James Clayton Prize derives from a fund established by the late Mr. James Clayton, who was a member of the Institution and chief engineer of Courtaulds, Ltd. The prize was first awarded for the year 1945, when the recipient was A. Cdre. (now Sir Frank) Whittle, by reason of his great pioneer work in the development of jet propulsion. The prize, accompanied by a certificate, was handed to Dr. Roxbee Cox by the Institution's president, Mr. A. C. Hartley, C.B.E., B.Sc.(Eng.), M.I.Mech.E., at a general meeting of the Institution on February 15th. On the same occasion the Thomas Hawksley Gold Medal, accompanied by a premium of £25, was presented to Mr. J. L. Norton, A.M.I.Mech.E., for his paper on The Design and Development of the Twin Centaurus Power Plant for the Bristol Brabazon. S.B.A.C on the Defence Statement FOLLOWING the publication of last week's White Paper on defence (see page 232), the Society of British Aircraft Con structors issued a comment in the following terms :— "Today's Statement on Defence 1952 contains certain estimates of manpower required for the Aircraft Industry, which, when the inception of nosewheels and were not specifically of nosewheel steering. More practical information was needed about tyres. An addition to the list of reasons for nosewheel steering was that differential braking often caused pitching, which was disconcerting to passengers. Aircraft inertia, which had to be overcome, was mentioned in connection with sensitivity, and it was also pointed out that too powerful steering led to heavy tyre wear. The lecturers had asked for pilots' views, and MR. H. N. BAILEY (Rolls-Royce) mentioned disadvantages of differential steering, fuel consumption being one of them, especially with jets, but, he added, with small and slow movements on the ground, differential use of engines had some distinct advantages. He went on to say that because of over-sensitivity at high speeds, a DC-4 he had flown needed considerable practice on the part of the pilot for correct handling of the nosewheel steering. Later he mentioned the payload advantage to be gained from nosewheel steering in helping to meet the engine-cut case on take-off. Before Mr. N. E. Rowe, R.Ae.S. Branches secretary, concluded the discussion Mr. Conway rose again to state categorically that coupled wheels, which, incidentally, could be made lighter than others, could not shimmy if adequate separation was arranged. He added that he felt power steering had been made to seem too difficult, whereas it was one of the easiest of hydraulic problems. This confirmed an earlier remark of a visiting Editor that "moun tains had been made out of nosewheels." MR. N. E. ROWE expressed the feeling of everyone present when he spoke of the lecturers' courage in presenting their paper, the first ever to be delivered on the subject. He pointed out, rightly, that much of the discussion had centred upon shimmy damping rather than upon power steering. He was very interested in the suggestion of solid tyres, and also mentioned the trend towards very high pressure in pneumatic tyres. He agreed that sensitivity in steering needed to be considered mainly at high speeds. Mr. Rowe also wondered how very low temperatures would affect sensitivity in view of the employment of very small valves. MR. G. E. PETTY, Blackburn and General Aircraft, and R.Ae.S. Brough Branch chairman (since 1921), rounded off the meeting with thanks, and then, together with other officials and a number of visitors, went on to the Royal Station Hotel for dinner. Among those present were Mr. George Dowty, vice-chairman, R.Ae.S. (Major Halford, the president, has, unhappily, been ill for some time); Mr. E. Turnery director, Blackburn and General Aircraft; Dr. A. Ballantyne, R.Ae.S. secretary; Mr. F. A. Wilkinson, Brough Branch secretary; and G/C. E. A. Warfield, the CO. of R.A.F. Station, Driffield. A tribute was paid at dinner to the long association with, and support for, the Royal Aeronautical Society of Mr. Robert Blackburn (at present abroad), who first became a member of the Society in 1911. compared with earlier official estimates, may be misleading. 'The Statement on Defence says (page 10) that: 'Before the programme started the labour force in the Aircraft Industry was about 150,000; it is now 177,000, and a further 50,000 will be required by March, 1953.' It is natural to compare this with the Economic Survey for 1951 (page 10) which stated that : 'About 175,000 additional workers are estimated to be required for aircraft factories and Royal Ordnance factories in the next two years.' "The Statement on Defence does not, however, give any explicit confirmation that the basis of the manpower figures is the same as before, and the Society advises caution in making comparisons." Mr. W. F. Wilson, who has been appointed to the board of Cellon, Ltd. During 25 years with these WmKKm well known makers of finishes, he WL Jk F. J. Smith (for many years in charge ^L ^P I of the accounts department) as
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