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Aviation History
1944
1944 - 1973.PDF
SEPTEMBER 21 ST, 1944 FLIGHT 323 ^ CORRESPONDENCE aircraft, so that he or she could be taken to and from the city or town served. Such a scheme developed on the correct lines should go far to assist in the development of the social side of flying, as no doubt many customers would become members of the local fly ing clubs which in turn might hold " sporting events " in con junction with car sporting events. Also it might lead to the development of air and combined road tours for tourists, there by building up our tourist industry. In fact the writer operated such a car and aircraft hire busi ness as far back as 1934 but was unable to develop the aircraft side of it for lack of airfield facilities, which difficulty should be far removed in the coming post-war years. I shall certainly look forward to other readers' views on this important topic, but wish to add that I heartily endorse "Indicator's" views, and would be one prepared to co-operate in such a proposed scheme for the development of civil flying. S. H. IIANDASYDE. I X No Subsidies or Government Control I WAS very interested in your Leader and the article by "Indicator" on ' Private Ownership or Public Hire" (Flight, Sept. 7th), because in 1914, if the war had not started, 1 would have started something on those lines. The Avro 504 was very suitable for the purpose and I was looking for an engine firm to take part in the scheme. However, the war stopped all that, and after three years I retired so as to get out to the Front, and nothing came of it. You ask readers to contribute their views. "Indicator" has covered the ground so well that there is nothing much to say but to agree with him. He mentions subsidies in passing. I am against them We built up the aircraft industry without them so there is no need for subsidies now. It is, of course, a different matter for the Reserve pilots and their refresher periods. " Indicatci " suggests that the Government might control his firm. NO! You want a body free to adapt itself quickly to altering conditions. For similar reasons I am rather against his Big-Business. I am in favour of competition every time; " Indicator " rather suggests it need not be " all-in-one-piece." I would favour each airfield having its one—or more—firms of hirers but all these firms all over the country working to gether, as he says, in healthy partnership. It would be possible. H. V. ROE. Is the Outlook Really So Bad? INDICATOR" seems to me to write in pessimistic vein in Flight of September 7th. As owner of a 130 h.p. Hornet (Gipsy Major engine), used mainly for Continental travelling, I found upkeep expenses light; petrol consumption, say, 6 gallons an hour for cruising speed, oil consumption low, hangar rent in Switzerland only ^ 30 francs a month. Since I flew largely over and among moun- takis I had the engine "looked at" after every 20 hours in stead of 25 hours as in England, but Swiss ground-engineers disposed of this job quickly and the craft was always at call. Though I kept no accounts, I should consider my general expenses as no more than those entailed by a small car. Leaving England in the morning I used to have tea at Geneva, Basle or Berne; and the next day perhaps I was over Mont Blanc having a ceiling sufficient for all Alpine sport, the most enthralling form of amusement which I know. Now in 1939 there was an even simpler and more promising model being tried out for the amateur; I refer to the Moth Minor in its coupe form. This craft was very easy, I found, to fly and presumably inexpensive to maintain. Quitp fast enough, too, for those who want to tour, and suitable for exploring mountains in the leisurely way required—petrol con sumption, 1 believe, at about 4J gallons an hour with Gipsy Minor engine. But "Indicator" suggests that even this kind of machine invites establishment of a standard of State inspection which will have to be paid for heavily. Surely existing inspection, coupled with the annual refit, is ample for any well-made machine which is allowed to take the air at all. Don't let us multiply parasites in the shapes of officials paid just to harass our lives in the ugly serfdom of the modern State. Such in spection as is necessary is furnished by ground-engineers. My craft never needed more. Far more important is an initial adequate training of the pilot, avoiding, thus, misuse of a craft. Given a good engine there's no excuse to be offered for most accidents occurring to the pleasure-craft of to-day. The game is not remotely as hazardous as, say, rock-climbing. No healthy man is too old for it. A word of caution. In places like the English Channel definite routes of travel ought to be arranged for different craft, collisions between liners and Joy-craft being possible in fog. But so far as may be, leave the joy-craft to themselves. Herbert Spencer's slave-world of socialism, into which the European modern state, created out of feudalism, threatens to grow, requires no special boosting on our part. "FREE LANCE." ENDURANCE AND RANGE Method of Engine Control Advised IN Flight of Aug. 24th, an article was published on Endurance and Range, by Sqn. Ldr. A. Sipowics, of the Polish Air Force. . , In the third paragraph of the article the following words appear: "The pilot has however, to choose between two possibilities; either less boost and higher r.p.m. or lower r.p.m. and greater boost. These alternatives as a rule do not give the same power for the same speed because the efficiency of the airscrew is different in the two cases." With reference to the crankshaft power, it is admittedly different in both cases. Surely to produce a definite reaction, such as a certain I.A.S. with a specified weight of aircraft, drag and altitude will require the same airscrew horse-power. This airscrew horse-power can be obtained in one ol two ways, i.e., higli r.p.m.—low boost, or low r.p.m.—high boost. The crankshaft horse-power will be extremely high with the high r.p.m., but a very large percentage of this power will be absorbed in overcoming the mal-etfects of the high r.p.m. The obvious aim is to reduce fuel consumption to the abso lute necessity for the requirements of flight. This can only be done by keeping the r.p.m. down to as low a figure as possible, with the highest boost obtainable at that r.p.m., the upper boost limit being the maximum' economical cruising boost. The method usually advised is to retract the throttle lever to the E.C. boost position, and then to reduce the r.p.m. to obtain the desired I.A.S. The advantages derived from this method of engine control can be annotated as follows: — 1. The supercharger impeller is being driven at relatively low r.p.m and consequently there is a reduction of the power required to dvive it. 2. With the reduction of the rotational speed of the impeller there will be a reduction in the temperature rise of the fuel/air mixture passing through the impeller. This will increase the volumetric efficiency of the engine. 3. The power required to drive the ancillary engine equip ment varies as the square of the r.p.m. Reduction of engine r.p.m. will reduce considerably the power required to drive the ancillaries. 4. High engine r.p.m. means excessive movement of the various working parts of the engine. This will give a sharp increase in the friction set up. Power must be absorbed in overcoming this friction. 5. There are other points which arise, all of benefit to the engine, sucn as lower bearing loads with a resultant increase in engine life; reduction of the amount of oil consumed; and finally from a psychological point of view, the lower r.p.m. will give a smoother running engine with increased comfort for the aircraft crew. The conclusion that anyone would arrive at, on comparing the obvious advantages of low i.pm. is that there is no choice of two possibilities. There is only one, the lower limit of the r.p.m. being governed by the limitations of the engine. For a certain make of aircraft engine with, say, a 1,000 r.p.m. range of airscrew control, the difference in fuel con sumption between the two extremes would be somewhere in the region of 10 gall./engine/hr. I. have not made any mention of the possibilities of detonation occurring in the engine. With the wrong combination of r.p.m. and boost the possibility of this happening is very high. With reference to the chapter on The Vector Diagram. Fig. 1 is said to represent a side-wind effect. The wind shown in this vector is not one which could-be called a side wind. It is a three-quarter stern wind. A side wind blowing at 90 degrees to the line drawn between the starting point and the destination, will at all times be equivalent to a head wind. To proceed from point A in order to reach point B, under these conditions, the pilot would have to turn the head of the aircraft into the wind, with a resultant loss of ground speed. RUPERT FORRESTER SIMMS.
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