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Aviation History
1909
1909 - 0351.PDF
JONE 12, I909. appreciated, viz., the necessity of dealing with a sufficient weight of air, also that an area of surface arranged in somewhat narrow strips is more efficient for the purpose, it appears to me to he self-evident what aspect the sustainer should take to make the most effective weight carrier. Suppose we imagine a sustainer built on this '' Venetian blind " principle, and see what it is capable of doing. Say the frame is 40 ft. wide by 20 ft. high, and the speed 60 ft. per sec, the weight of air dealt with in this time will be approximately 3,840 lbs. ; taking the downward speed imparted to that weight as 7 ft. per sec. then the reaction or lift will be about 834 lbs., the horse-power being expended to maintain the load. Under these conditions, being 5^, it takes no account of any other resistance. If, as I suggest, the surfaces be placed 3 ins. apart, we shall have an efficient area of 400 sq. ft., the weight carried being something over 2 lbs. per sq. ft. For the sake of transverse stability in turning, it appears to me that the sustaining surfaces should be arched transversely, the ends curving downwards, more particularly in a system where the centre of gravity is kept low. This suggestion may not be new, although I have not seen it put forward before, but I consider it of some importance. Such a frame of sustainers, by careful design and workmanship, should not weigh more than about 75 lbs., and I should like the task of building one. In a most interesting paper, read by Mr. Wenham and published in the first annual report of the Aeronautical Society, in speaking of a gull that was following in the wake of the vessel he was travelling on, exclaims : But where is the angle or inclination of his wings to counteract his falling tendency ? for to all appearance his wings are edgewise or parallel to his line of motion, and he appears to glide along a frictionless support, &c. This goes to show that the angle was small, and I am not altogether certain that a line drawn from the front to back edge should show any angle at all with these narrow concavo-convex surfaces when in flight. In machines built on the monoplane system we have an extreme type; with the " Venetian blind " system we have the other extreme. I have no doubt in my own mind which is the more efficient. I do not wish to pose as an expert, who, while doing little or nothing successfully himself, undertakes to teach others how to do it; but, as a mechanic who has had somewhat exceptional oppor- tunities of assisting at experiments, I feel certain that machines built on the monoplane and biplane system are not the best that can be designed, and to those about to experiment in this direction I would say, study the subject, and think, not blindly follow, simply because one or two others lead. Yours truly, Shepherd's Bush. F. H. PHILLIPS. TO ENCOURAGE PIONEER AVIATORS. To the Editor of FLIGHT. SIR,—No doubt a number of your readers will wonder what English aeroplane builders are doing. As far as I am aware they are pushing ahead with all possible speed, although much pioneer work has been done abroad, and in England there still remains much to be done. One would naturally think after an aeroplane is built, all the aviator had to do was to start up the engine, run along the ground and into the air. But, however carefully an aeroplane has been designed and built, it takes considerable time for adjusting, practising, &c, as all sorts of unforeseen delays keep constantly cropping up, and to even make the first step, namely, to obtain sufficient speed to rise, may run into months. As the pioneer has naturally so many difficulties to overcome, and as he paves the way for those who follow, I think he ought to be encouraged by prizes for the first steps. True the Daily Mail have very generously offered £\,ooo for a mile circular flight, but I think smaller efforts should also be encouraged. I suggest prizes could be offered to British-built aeroplanes accomplishing the following :— 1. First aeroplane to run along an ordinary field at 25 m.p.h. 2. Fly 100 yds. 3- i mile. 4. £ mile. 5. For the aeroplane that flies with the smallest h.p. engine. 6. The lightest aeroplane. 7. The smallest span. 8. Most portable aeroplane. 9. The slowest aeroplane. 10. Fastest aeroplane. 11. The aeroplane with greatest range of speed, that is, slow or fast. If a rapid growth of the movement is desired, then the small aeroplane with small horse-power should be encouraged above all, for I fear only a limited few will go in for the costly high-powered heavy aeroplanes. Personally I think the Daily Mail £10,000 will be won by a small, light, handy aeroplane of small horse-power, capable of travelling at speeds ranging from 25 to 40 m.p.h. Yours faithfully, A. V. ROE. P.S.—If any of your readers are on the look-out for a smooth large trial ground, I know of a place within 10 miles of London; there is also an aeroplane shed available adjoining ground, measuring 36 ft. wide, 12 ft. high doors, and 40 ft. long.—A.V.R. FLAPPING-WING MACHINES. . " To the Editor of FLIGHT. SIR,—As a devotee of many years' standing to the study of aviation—including many and varied experiments in aerodynamics— half a lifetime of fifty years, in fact, with a good slice of that period devoted to flapping-flight, I am desirous of offering a few comments on the subject of the article " Flapping-wing Flight," published in your issue of 29th ult. Let me premise that I am sanguine as to the ultimate success, and general use, of ornithopteres and analogous winged machines, but, in my belief, success most certainly will not be achieved by means of any system of " valvular " wings. As long ago as 1884, my esteemed and lamented friend, the late Mr. Brearey (B.Sc, &.c), joint founder of the Aeronautical Society—and second to none in a profound knowledge of the subject—alluded to " that exploded fallacy of valvular wing action " ; thus we see it was " blown up " over a quarter of a century ago. Such hypothetical valvular action not only certainly does not occur in natural flight—and is therefore not essential to it—but many ex- periments have demonstrated that it is equally futile in schemes of aviation. The membraneous-winged flying mammals and insects bear indisputable witness that it is not essential nor used at all. It must, however, be conceded that it is a plausible hypothesis, and it is due to this plausibility that, like many experimenters before and since, my early essays (in 1880) were in that direction, but I soon realised its futility. Shortly after that period, becoming acquainted with Mr. Brearey on joining the Aeronautical Society in 1883, I had the support of his valuable experience and testimony to the entire discredit of valvular wing action. It is much to be deprecated that the writer of the article should seriously entertain this chimera, much more advocate it as a likely means of practical flight, and it is also surprising. It is misleading, and calculated to induce novices to waste much valuable time on a long discarded and fruitless line of experiment. The writer talks too about " the idle stroke " ! Does he not know that there is no idle stroke in natural flight, and that there need not be in artificial flight ? The upstroke of the wing has its functions as well as the downstroke. : Yours faithfully, York. SIDNEY H. HOLLANDS. [The article in question was written solely for the purpose of drawing specific attention to the difficulty and drawbacks of a principle which is often brought up for discussion ; there was no intention of advocating its adoption by experimenters—rather the converse.—ED.] BRITISH INVENTIONS AND FOREIGN ENCOURAGEMENT. "*" ' ' To the Editor of FLIGHT. SIR,—In reply to your various correspondents who have taken exception to my remark re capitalists, I must say that their ideas as to what a capitalist is seem rather foggy. What they all appear to be looking for is a speculator, which is a very different thing and no doubt hard to find. Mr. Maxwell also appears to think that invest- ment and speculation are synonymous. If Messrs. Foster and Maxwell would disabuse their minds of the idea that they are offering subjects for investment when they are only bringing forward schemes for speculation, they would begin to understand the (to them) incomprehensible shyness of the moneyed individual. I may remark here that Mr. Maxwell's correspondent who " wanted the earth " for his paltry ,£50 is not a specimen of the genus " capitalist " but of the cautious gambler. It appears a remarkable thing to me that Mr. Maxwell, with all the facilities he mentions for building a flying machine, does not build it at his own expense, knowing that on account of the said superiority he would easily be able to repay twice over any small loan he might negotiate ; that he does not do so, but seeks to share the risk, does not show overwhelming belief in his invention, or ability to grapple with attendant difficulties. 353
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