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Aviation History
1933
1933 - 0776.PDF
FLIGHT, OCTOBER 12, 1933 QjMUfxwjckttftt. The Editor does not hold himself responsible for opinions expressed by correspondents. The names and addresses of the writers, not necessarily for publication, must in all cases accompany letters intended for insertion in these columns. POBJOY MODIFICATIONS [2877] 1 have recently obtained from the manufacturers a list of 12 upkeep notices and modifications to Pobjoy engines. I understand from the service agents that these form part of a list of some 45 modifications which are available on Pobjoy engines of various dates. Now, since these notifications as to modifications have not yet found their way to the majority of private owners, and since a knowledge of the alterations recommended is essential to the life and the reliability of the engines, it seems well that one should advise them through your columns that a full list-is obtainable from the manufac turers on demand. Private owners will then become aware of the steps which can be taken to overcome their present difficulties, and will be able to gauge the amount of work involved in their next overhaul for C. of A. The list includes the following of special interest: — 1. Prevention of engine failure in snow storms. 2. Prevention of slipping on re-modified magneto couplings. 3. Prevention of cracking on internal parts of the above. 4. Prevention of cylinder warping, etc., by uneven air cooling. 5. Prevention of erratic mixture control through side loads on altitude cock. I understand that in addition to the above 45 notices, two or three more are now " on the stocks." These aim at the reduction of oil leakage in the region of the pro peller boss, a tendency which reveals itself after a number of flying hours. POBJOY OWNER. London, E.C.2. October 3, 1933. [Below is Mr. Pobjoy's answer to our correspondent, which states clearly the manufacturer's point of view.] We would explain that the twelve or so Owners' Upkeep Notices do not refer to modifications, but contain hints on maintenance aimed at assisting the operator to obtain the best results and to carry out simple overhaul opera tions. These notices are circulated from time to time to our repairers, service agents and aircraft makers, and also to as many of our private owners as are known to us. We are generally able to keep in touch with owners of new engines through our guarantee, but it is not always possible to trace the fortunes of second- and third-hand machines. Every six months these notices are reprinted in con venient form and are included in the handbook issued with each new engine. A supply is also issued to service and repair agents for distribution to owners as required. The forty-five modifications referred to by your corre spondent are in quite a different category, and represent alterations, many of them unimportant, which have been made to our R-type engine since it was introduced three years ago. In order to comply with Air Ministry require ments it is necessary to keep an accurate list of such alterations, and for their own information we supply copies to our agents. It is, however, quite unnecessary for the private owner to be bothered with the information, and the service agent was quite wrong in otherwise advising him. The list in question is divided into three classes of modi fications : Obsolete, Non-essential, and Essential. The first class are not applicable, the second class are of minor im portance and may be introduced if the owner wishes at the next overhaul on the advice of his repair agent, who is already in possession of the list and familiar with it. In accordance with the regulations, Essential Modifica tions must be dealt with either by the issue of an Air Ministry " yellow notice " or by the engine makers' own action. All Pobjoy engines in existence have received all the essential modifications but one from us, the engines having been recalled to our works for the purpose. The one exception is the fitting of the warm air intake for snow flying, which is covered by Air Ministry Notice to Owners and Engineers, No. 35, of the year 1933. Inci dentally, this is the only " yellow notice " yet issued about our engines. In regard to the specific points mentioned in your correspondent's letter: No. 1 is covered by the above- mentioned notice, which should have reached him through the official channels. Nos. 2 and 3 specifically state that they need not be applied to engines in actual service, and in any case are now obsolete. Nos. 4 and 5 are purely installation matters for the attention of the airframe maker, and refer to the layout of controls and to the desirability of fitting the Pobjoy or other approved type of inter-cylinder air deflectors. We trust that these remarks will allay your correspon dent's doubts, and we should like to take this oppor tunity of asking him never to hesitate to write direct to us when in any difficulty. Our service department, whose main object is to assist the owner, is often handicapped by the tendency of operators to nurse difficulties to them selves—probably magnifying unimportant points while neglecting serious features—whereas a l£d. stamp would bring helpful advice and, if necessary, practical assistance. Incidentally, our handbook is provided with all new engines and contains full maintenance information. Finalty, we would extend a cordial invitation to your correspondent to visit us at our works at Hooton in order that we may make his acquaintance. POBJOY ATRMOTORS, LTD. (D. R. POBJOY, General Manager.) A HIGH-SPEED RECORD FUND [2878] I am very much interested in the recent sug gestion put forth by your readers in Australia, that finance could be raised to enable Britain to regain the world's air speed record. I do not doubt that the public would be willing to subscribe, but according to a newspaper I read some while ago, Lord Londonderry stated that even if a donor presented the necessary sum the R.A.F. would not be permitted to make an attempt, owing to the dangers on life it would impose. If this is correct, then the whole idea is useless, unless a suitable civilian pilot took on the job, and even then a new machine must be purchased or the old " Supermarine " re-designed, that is, of course, if the Government would loan it. I think the scheme from Australia is excellent, and it would be interesting to know what other readers' views are on this subject. ERNEST W. BAKER. Cranwell, Lines. September 23, 1933. FASTER AIR MAILS [2879] The recent deputation from the London Chamber of Commerce to the Secretary of State for Air showed that there is a demand for a faster air mail service. For some years the London Chamber of Commerce has been trying to induce the postal and other authorities concerned to increase the air mail facilities offered to the public, but with little apparent success. Whilst some other countries put on a fast air mail service, knowing that its very existence will soon produce the necessary demand for its services, this country has not sufficient initiative to start one even when the demand comes first. This petition for faster air mails comes only a few days after the conditions for the extension of our air line to Australia are announced, in which a cruising speed of 95 m.p.h. for the next two years is asked for. Commercial aircraft are getting faster every year, and yet the Austra lian Government will be satisfied five years hence with 110 m.p.h., which is below the cruising speed of the fastest Imperial Airways passenger carriers of to-day. The Royal Dutch Airline ran their service from Holland to the Dutch East Indies at a cruising speed of 122 m.p.h. during 1932, and faster aeroplanes have already been ordered. This is not the only foreign air line with faster aircraft than ours, but I have quoted it because it shares with Imperial Airways the distinction of running on a subsidy which forms only about 50 per cent, of the receipts, whereas some Continental air lines have been receiving over 80 per cent, in subsidies. E. N. B. BENTLEY. West Drayton, Mddx. October 5, 1933. 1036
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