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Aviation History
1945
1945 - 0721.PDF
APRIL 12TH, 1945 FLIGHT 403 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 all cases accompany letters. JET PROPULSION What Happens to the Thrust ? J HAVE read with interest the recent articles on jet propul-sion, but there are three points arising which are not quite clear. First, if the propulsive force of the aircraft is due to the reaction of discharging hot gases into the atmosphere, which part of the structure is stressed to take the thrust? On an aircraft moved by a propeller (to use the Service term), the thrust is transmitted via the thrust bearing to the engine mounting. On the jet propelled aircraft it might seem to be distributed over the whole surface area. Secondly, where does the thrust line lie? If, as suggested above, it acts all over the aircraft, it will coincide with the drag line. It seems more probable, however, that the thrust will act through the turbine and compressor. Lastly, if the fuel consumption is given in pounds/h.p. hour and the power is measured in pounds thrust (as in Air Comdre. Banks's paper), what is the conversion formula to use? Perhaps some of your readers could clear these problems up ^by the adroit use of a couple of masses and three or fourN .locities. As for the last one, it defeats my supercharged, power-operated, electro-hydraulic slide rule. P. A. HEARNE. THE SLIGHTED SERVICE Gratitude for Services Rendered ?F OR its traditional modesty and for its unpretentious ways, the Royal Navy has earned for itself the title Silent Ser- vice. One is tempted to bestow upon those of a less tradition- ally endowed but no less _unassuming body, the title, Slighted Service. I refer to the Royal Observer Corps and, in particular, to the voluntary, part-time, post observers. There has been of late such a spate of criticism, ad nauseam, levelled at our much-maligned and long-suffering- government that it is with reluctance that I would add yet more to the din, but my criticism is, I trust, justified and, I am convinced, fair. It was announced recently that gratuities would be awarded to certain of the civilian services in recognition of their various contributions, amongst which was listed the R.O.C. I wonder, however, apart from those in contact with the Corps, how widely the facts of the gesture were appreciated ? Unless I am misinformed (and I do not believe this to be the case) it is an apparent fact that only those members of the Corps classified "A"—that is the whole-time members—will qualify for these gratuities, which though not considerable represent quite a fair sum when considered for the full period of the war years. The " B " members, however, fail to qualify. Let us ponder awhile. The full-time man, as is implied, does nothing else (as re- garded at least by Official Eyes) but man his post, for which he is paid, if not handsomely, a sum each week which is in excess of that collected by the bemused " B " member. He does not deviate from his normal pursuits nor does he suffer unduly from the consequences of a disorganised day. On the other hand the unfortunate part-time man may have to arrange his work to fit in as a subsidiary item to what was once no more than a hobby, and sink the ensuing inconveniences in his enthusiasm, lacking which there would appear to be little or no prospects for it. It must be very apparent that, without wishing to minimise the work of the "A" men, the greater contribution is made by these part-time people, who, however, fail to qualify for the gratuity. Why has this most unjust decision been made ? The question of gratuities was bound to be unsatisfactory, and one is forced to the conclusion that they would be better far to have been given to the three fighting Services only, rather than ladle out these inconsistent sums in such a haphazard and indifferent manner. The Official Eye is a cold and frigid one, and is accepted as • such, but of late there have been distinct and too frequent signs of myopic trouble accompanied by periods of forgetful- ness, the effects of which have both hurt and discouraged those who have suffered. I am not a "B" member of the R.O.C. so my grievance is a purely impersonal one, but this stupidity is being felt by the voluntary men who have devoted so much time and energy to their work. It is not the loss of the gratuity that they resent but the shabby and indifferent way their services are acknowledged. SENTEK. I THE CURTISS ASCENDER And Other Experimental Fighters N your article on the Curtiss Ascender which appears in • Flight, April 5th, the author rather labours the point that it was thus named because it could climb fast. Actually, the origin of the name is more subtle than that. The principal characteristic of this aircraft is that it flies back-end first—in other words, it is a backender. Substitute a more Rabelaisian word for back, and you have the answer ! Regarding other aircraft mentioned in the article, there is little mystery about any of them. The MacDonnel XP-G7 is an experimental twin tractor monoplane with a skate-shaped plan-form. It has already been illustrated in many publica- tions both here and in the United States. [See Flight of Feb. 22nd, 1944.—ED.] The RP-64 is really the rather ancient North American NA.50 single-seat fighter, six of which were ordered by Siam in 1940 When the United States entered the war these aircraft were im- pounded and incorporated into the U.S. Army as advanced combat trainers under the designation RP-64. The prefix R (Restricted) signifies that they are not considered fit for com- bat use. The XP-37, XP-42 and XP-46 were all experimental Curtiss fighters. The XP-37 and XP-42 were both converted P-36's, the former fitted with one of the earliest Allison V-1710 engines and a turbo supercharger, and the latter with a special Pratt and Whitney engine with extended airscrew shaft for enclosed cowling experiments. The former dates from 1937 and the latter 1940-41. The XP-46, which also dates from 1940-41, was an attempt to improve on the original P-40 both in per- formance and armament, the latter being interesting in featur- ing a combination of the then U.S. and British standard fighter armament—two 50-cal. fuselage guns and eight 30-cal. wing guns. It never proceeded beyond the experimental stage. LEONARD BRIDGMAN. SELLING AIR SAFETY Importance of Cheap Fares "VTOUR correspondent " Realist " (Flight, March 20th), at JL first reading, appears to hit the nail on the head in sug- gesting that a publicity campaign will be necessary to " sell " the public the true facts of safety in air travel. Second thoughts, however, may alter this opinion. Publicity cam- paigns are expensive. The end of the war, with the return to civilian life of thousands who have flown safely many thousands of miles, and the continued actual existence of cheap, I repeat cheap, air travel will in quite a short time overcome timidity in progressive people. The non-progressives will never be convinced anyway. Were they in the birthdays of railways or motor cars? No. But as soon as such travel became cheap things went all one way; witness the popularity of motoring, despite a deplorable death rate due to car accidents. Unfortunate emphasis has recently been laid on air accidents involving " very important personages," on the crashes of friendly aircraft involving" civilian casualties on the ground, damage to property, etc. Such " news " as portrayed by the daily Press is out of proportion by reason of security silence being maintained about the number of air-miles flown in total by the Services. I suggest that when it is possible to show by figures that the number of " accidents " compared with air-miles flown are infinitesimal, the public view of air travel will change, and if, in addition, air-travel can be proved to be reasonably cheap compared with other forms of transport, always bearing in mind that we have to pay for speed, then it will, almost automatically, become popular. This in spite of spontaneous and ignorant statements made by B.B.C. broadcasters, as mentioned by " Realist." I would rather see " publicity campaign " money used to cheapen fares so that the day may quickly come when the public will step into an aircraft with the same assurance as they did into a railway carriage before the war. '' NAPPER."
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