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Aviation History
1948
1948 - 1053.PDF
JULY 8TH, 1948 FLIGHT 53 CORRESPONDENCE The Editor does not hold himself responsible for the views expressed by correspondents. The names and addresses of the writers, not necessarily for publication, must in ail cases accompany letters. AIR AND GROUND CREWS IN 1960 From Where Will the Wastage be Made Up ? WITH the release of thousands of trained engineers andaircrew from the R.A.F. at the end of the war, the civilaircraft operators found many willing and trained men laid figuratively at theii doors. Look ahead to about i960. The R.A.F. will not be releasingmore than a mere trickle of men and our present-day civil pilots and engineers will be middle-aged. Apprentices atpresent learning aircraft engineering are few and far between and the methods used at present to train them are an insultto the word apprentice. A»No civil operators, including the Corporations, are taking %fly action in the matter, and as the old willing horse will doubtless be flogged to death, I see the aircraft industry ofthe future as a few really skilled engineers, leading a crowd of ex-motor mechanics and plumbers, from headline crash to crash. The Corporations should set the lead now by training boys when they leave school, and giving them study facilities on a similar level to the R.A.F.'s Halton. If we don't wake up soon, I, personally, fear the worst. T. D. KEEGAN, Godalming, Surrey. Licensed Engineer/Pilot. DIESEL ENGINES FOR AIRCRAFT A Realistic View of the Problem From Sir Roy Fedden, M.B.E., F.R.S.A., D.Sc, F.R.Ae.S.,M.I.M.E., M.S.A.E., M.I.A.E. HAVING made a study of diesel engines for aircraft for thelast twenty years, and having been closely associated withthe only British aviation diesel engine which has operated suc- cessfully over long periods, both on the bench and in the air(and which held the diesel altitude record, viz., the Bristol of the early thirties), 1 am venturing to add a few comments inthe hope that they may help to dissipate some of the inept statements which have appeared in your corrspondence columnslately on this matter. First, in order to be specific and logical, it would seemadvisable to decide what type and size of aircraft engine the diesel protagonists would recommend should be the first to bechanged over to this principle, and what this entails. It will be assumed, for the purpose of furthering this argu-ment, that a power plant of 2,500-4,000 h.p. for large trans- continental and trans-oceanic aircraft would be the mostattractive size to embark upon first. Let us see exactly what this would mean. It is significant to note that in the lasttwo world wars the best aircraft emanated from the country with the most progressive engines. Also, that in spite of allthe effort poured out on aircraft engines during the last two decides, the reason why no country has seen fit seriously to"S&t its money" on the diesel was that the principle could not show sufficiently promising results for military use. It isalso necessary to realize that no' large-size aircraft engine has ever (or can, in effect, ever) come to full fruition unless it issponsored on a national basis, and unless it goes into a suffi- cient number of important military machines to eliminate allthe inevitable teething troubles that always occur. In other words, the successful air-liner power plant of to-morrow shouldbe the obsolescent military engine of to-day. In 1930 I had the honour to prepare a complete survey ondiesel aircraft engines for the International Air Congress of 1930, held in Holland, which paper was read at The Hague. The arguments put forward at that date, and the conclusionsarrived at, hold good to-day, except that the case for the diesel has become worse owing to the great drive on high-octane fuel initiated in the U.S.A. in the middle thirties, and the fact that in 1930 the valuable rich-mixture characteristicsof the petrol engine temporarily to increase power for take-off had not been fully realized or exploited. As was broadly foreseen, there is no reason whatsoever todoubt that a perfectly sound, satisfactory and reliable diesel engine in the 2,500-4,000 h.p. category can be produced. Fora given bulk and weight it would deliver about 25 per cent less power for about 25 per cent less fuel consumption. Thefuel, at a rough approximation, would cost about 25 per cent less than high-octane petrol. The cost of designing, developing and bringing to a stage where this engine was safe to fly passengers across the Atlanticwould be at least £5 million to £7 million, and the time not less than eight years. This engine could not earn its keepunder 5,000 miles range; there is little doubt it would have a lower fire risk than a petrol engine; it would never be con-sidered for military purposes. What justification is there for footing such a bill? BritishGovernment policy has committed this country to jet turbines and airscrew turbines, and although the latter have beengrossly oversold, and are some years off being an accomplished fact in the sizes we are discussing, I cannot believe they willtake more than eight years from now to perfect, and they can always employ fuel which is as safe from a fire-risk pointof view as the diesel fuel. I am afraid the picture would be a bit worse for the 1,500-2,000 h.p. engine. This diesel engine drive should have been made about twentyyears ago, before the remarkable progress on improved petrols had been launched, with all the implications of big businessconnected with it. If the diesel could have been firmly estab- lished at that time, when we were struggling with 70-72 octanefuel for our aircraft engines, then it might have had a chance, but now, never ! ! I believe the only diesel we are ever likely to see in aviationis Sir Harry Ricardo's most intriguing "Triple Expansion" thesis, wtiich employs the whole exhaust from a two-strokediesel for the purpose of driving turbines. It is just possible that such a project might be worth while, as it has such anextremely attractive fuel consumption, but I c;.n only see this engine "staying the course" if it can be introduced andstandardized on two or three important long-term military machines, while they are in the project stage, which wouldthus automatically ensure the long and heavy expenditure that is necessary for its successful realization. Turning for a moment to the light aircraft power plant, therequisites of specific weight, fuel, stiffness and strength ratio, are such in the 100-250 h.p. classes that I believe it mightwell be possible to produce in this category a diesel which would be more attractive and would pay a much smaller weightpenalty. Further, in such a power class it would be free, at least for agood many years, from the competition of the airscrew tur- bine. However, such an engine would cost more than a petrolengine of the same power, and as official British support has been denied to all aircraft engines under 250 h.p., I cannotsee much hope in this direction either. I am afraid, therefore, that there is no possible sound tech-nical or practical argument for the accepted form of diesel engine in British Aviation. ROY FEDDEN. London, S.W.7. FORTHCOMING EVENTS July jOch.—Daily Express Air Pageant, Gatwick Airport. July 14th.—R.Ae.S. (Hatfield) : Film Evening. July 17th.—Southend-on-Sea Air Rally. (Cancelled). July 17th.—Women's Junior Air Corps : Summer rally at Hendon airfield. July 18th.—City and County of Newcastle-upon-Tyne : Air display at Newcastle airport, Woolsington. July 19th to 31st.—Swiss International Gliding Competitions, Samaden. July 21st.—R.N.A.S. Arbroath (Angus) H.M.S. Condor : Visitors Day. July 24th to 26th.—Private Air Rally for members and associate members of the Royal Aero Club at La Baule-Escoublac, St. Nazaire. (Guests of M. F. Andre). July 31st.—Aero Club of Orange Air Rally. July 31st. to Aug. 8th.—International Model Aircraft Meeting, Eaton Bray, Beds. Aug. 1st.—Boroden Cup for Model Aircraft with mechanical engines, London Region. Aug. 7th.—Air Meeting and Competitions at Ypenburg, Holland. Aug. 7th.—Midland Aero Club : " At Home," Elmdon airport. Aug. 14th and 15th.—Butlin's Week-end Air Rally at Broom Hall, Pwllheli,N. Wales. Aug. 21st to 29th.—International Aviation Week, Grerchen airfield. Aug. 21st.—Wiltshire Flying Club : Thruxton air races, Thruxton airfield, Andover, Hants. Aug. 22nd.—Cowes Aero Club : Annual air display, Cowes airport, Isleof Wight. Aug. 26th.—R.Ae.S-. (Glasgow) : Lecturettes, Grand Hotel, Glasgow. Aug. 26th to Sept. 11th.—Machine Tool and Engineering exhibition, Olympia, London. Aug. 27th to Sept. 5th.—Aero Club de France. " Tour de France." Aug. 28th and 29th.—Cinque Ports Flying Club : International flying meeting, Lympne airport. Sept 4th and 5th.—Butiin's Week-end Air Rally at Speeton, Filey, Yorks. Sept. 7th to 12th.—S.B.A.C. Exhibition and Display, Farnborough airfield Hants. Sept. 18th to Oct 3rd.—Copenhagen Show, organized by the F.B.I.
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