FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1911
1911 - 0491.PDF
JUNE 3, 1911. CORRESPONDENCE;. *.* The name and address of the writer (not necessarily for publication) MUST in all cases accompany Utters intended fot insertion, or containing queries. Correspondents communicating with regard to letters which they have read in FLIGHT, would much facilitate ready reference by quoting the number of each such letter. Power for Flight. [II97l In reference to some of your most interesting articles on the problems of flight, the following considerations puzzle me a little, and I do not like the fashion of getting away from the real question by saying that birds are living creatures and therefore excel machines. This is not so with the horse and the cycle or motor. According to the figures of Langley and others 50 condors or 100 wild geese, if all on a string, could support and carry a man in the air— the whole lot exerting a force of about z\-h.p. Similarly with 30 or 40 golden eagles, according to the accounts of naturalists, who tell us they can lift 5 or 6 lbs., or even much more. What puzzles me is that this should be so, though our best models of the size of the bird are so inefficient and though we are told that the small machine is wasteful as compared with the larger. Certainly propellers of small diameter are inefficient. Yet here we have something in the nature of a propeller which though small yet can give thrust. In fact the 30 eagles represent 30 propellers and 30 small planes with all the theoretical increase of friction and waste of power. Now a single machine or bird of equal power with the team above-mentioned would have a high starting, landing, and flying speed. So the conclusion that I am faced with is that for easy management a team of six ft.-span models would be better than a single full-size plane ! This looks absurd. However, there is one practical conclusion I draw. We are too modest about our models. We are shy of putting in weighty engines. The wild goose has an area of 27 sq. ft., a weight of 9 lbs., an estimated h.p. of C026, and gets along unaided ; while the condor, with a maximum span of 10 ft. and an area of 10 ft., weighs 17 lbs., and exerts up to 0^05 h.p. (Langley's figures). Even heavier is the trumpeter swan—28 lbs., with a span of 8 ft., so there is lots of room for our model makers to improve the efficiency of their planes and propellers, while they need not be looking for ij-h.p. engines weighing 3 lbs. complete. Nor need they put all the blame on head-resistance, as even a small kite or eagle can fly with a rabbit in its talons. A. F. M. [The most important result of Langley's research was his demonstration of the internal work of the wind. He showed that wind pulsations, gusts, and up currents were sources of energy that could be turned to account by any living creature or machine capable of making use of them. Birds have a natural instinct for taking advantage of every atmospheric condition, but man has not reached to this stage.—ED.] Aviation and Common Sense. [1198] With regard to the above article by Mr. F. T. Wilbur in your issue of May 6th, he suggests that the probable cause of many aviators giving up flying, through impaired health and nerve strain, is really due to the effects of a deficiency of oxygen in their blood from the continuous flying in an atmosphere of lessened pressure. It may be interesting to him and others of your readers to know that there is now a small machine, weighing 2 lbs., to be had, which is claimed to make up for this very deficiency, and in a remarkable manner. Let me say that I am not in any way connected with the producers of the machine. Pontypool. V. SWANTON. E. G. Norfield's Model Farman. 493 (7QGHT) MODELS. Tails on Models. [1190] With regard to Mr. S. P. Elliot's letter (No. 1083) on tails. I thought that I was the practical original or ol the tail twisting device for steering, for I used it on my full- - sized glider, which I constructed last April, and found it very efficient for steering and also for balancing. Thames Ditton. C. B. RIDLEY. Model Voisin and an Engine Wanted. [1200] For some time past I have been making a model of the very latest Voisin biplane. That is to say, the type which was shown at the last Paris Salon. The machine has a fuselage of the correct shape and approximately the right size. Will you give me a simple sketch of the landing chassis of the Voisin, and of how it could best be applied to this model. I want to fit it with a petrol engine. Perhaps some reader will advise me what power this ought to be, and how much weight the machine would carry. Each of the main planes measures 5 ft. by %\ ins. The tail, carried 3 ft. 7J ins. behind, has an area of about I sq. ft. Of course, there is no elevator. Wellington College. P. LEOH. [The accompanying sketch may perhaps be of assistance. The engine problem is one that must necessarily be determined by the selection of motors already on the market, which are not very- numerous.—ED.] Model Farman. [1201] Enclosed herewith are photos of my model Farman biplane. The main planes are 36 ins. span and 6 ins. chord, the gap between the planes 7 ins., and overall length 39 ins. The model is now fitted with another propeller. I may add that it was shown in an exhibition at which it gained a prize. Cambridge. E. G. NORFIELD. Centrifugal Force. [1202] As " Enthusiastic " (No. 991) invites criticism may I say a few words. He has fallen into the error that has caught a very large number
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
