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Aviation History
1937
1937 - 0426.PDF
156 FLIGHT. FEBRUARY 18, T937. Topics of the Day These Ultra'lights M ANY months ago I suggested that if there was one thing which would hold back development in the ultra-light market, that thing was the lack of really suitable power units. After flying a few more examples I have seen no reason to alter that opinion. Easy to fly, and safe as most of them are—as aeroplanes —my experiences have often been spoilt by an entire lack of confidence in the reliability of the engines fitted, and by the lack of power provided by them for climbing pro pulsion, even when they have been running quite well. Let it not be thought that I expect too much from the little fellows, but many of them are grossly under-powered for safe departure, in a flat calm, from any aerodrome of less than the thousand yards' calibre. It is all very well to say that these machines are usually meant only for aerodrome flying or for short trips in good weather, and, at the same time, that they are designed for use by novices. Aerodrome flying demands, above all things, a good take-off, a fair climb and a reliable engine, and a novice is the last person to be able to deal with deficiencies in any of these. Some of the ultra-lights of which I have had experience are so under-powered that they will only climb properly at one particular speed. Fly them at 40 m.p.h. and they wallow along tail down without gaining height; fiy them at 50 m.p.h. and they scrape the tree-tops. Don't tell me that a novice can deal safely with that sort of thing—even if the engine doesn't stop just as the boundary is crossed. Near the ground they are temperamental little affairs and their strongest point concerns the fact that trees, houses and telegraph poles are likely to be smitten always at sub-lethal speeds. It is depressing, anyway, to be overtaken, both in speed and climb, by some mediocre bird which has taken off at the same time as oneself and turns on its way to give you a pitying glance. Nor is there anything very remarkable about low-power flying. In the long-ago Lympne trials the E.E.C. Wren flew quite well on an A.B.C. motorcycle engine developing a maximum of 10 h.p., and a little later the first Daimler- Klemm carried two people on 20 h.p. at 62 m.p.h. Unreliability J V you think that I am exaggerating when I speak of 1 unreliability let me ask you, first of all, how many ultra lights have been made and flown here in the last two years. Excluding Drones and the defunct Poux, perhaps ten. Of these, two which I have actually flown have since been crashed, with considerable damage to the pilots through sudden engine failure. That, I may say, is a very poor average. Aeroplanes almost did better in 1914 Until somebody produces real aero engines in small sizes I shall prefer, in most cases, to face the ridicule of braver souls by flying, pleasantly enough, within approximate gliding distance of an aerodrome. I demand an aerodrome because it is not safe to make forced landing approaches into small fields with machines on which side-slips cannot be held and on which steep gliding turns are sometimes made abominable by the low-speed effect of aileron drag. After several hours in any one of these ultra-lights a pilot would undoubtedly learn to pull off reliable spot landings without using his engine, but the ability requires semi-sailplane experience which can only be acquired with practice—and which has not yet been acquired by me. At present when I want to gain height in an ultra-light all the down-draughts conspire against such a project, yet, when I reach the proximity of the aerodrome and wish to descend, it appears that I have found all the up-draughts in the district. None of which forms a criticism of ultra-light machines as such. One or two of them have safe and pleasant characteristics which might well be applied to our stan dard light aeroplanes and are certainly worthy of better means of propulsion. Others, in their own different way, are more difficult to fly than the aeroplanes which are popularly supposed to be beyond normal capabilities. The manufacturers of play-planes must also remember that even the most enthusiastic amateur will eventually tire of a game which affords no variety, and that for fly ing enjoyment, per se, there is probably nothing to toucii soaring. Consequently, these maufacturers must provide a machine which is capable of serious work. More Power C'OR such machines we require real and reliable engines * in two sizes, for single-seater and two-seater or sports- single-seater work. The first might develop something in the region of 30 h.p.—genuine and continuous—and the second might be in the 50-60 h.p. class. The latter demand may eventually be filled by the Weir, and already the Czech Walter Company produces, in addition to the little Atom eneine, the Mikrcn four-cylinder, which more or less satisfies the requirements. I should hate to prophesy a really useful market for either size, but there should be a sale of a hundred engines a year for each after the airframe manufacturers have had a chance to design machines around them In the first year sales would probably be limited to the odd twenty or so fitted to prototypes and demonstration machines. The private-owner market would only develop after a year or two of successful solo school use. Nobody bu-. a super optimist could expect the average club pilot to spend a sum—large in proportion to his payments in clu and other hire charges—for a machine which has not shown that it is both reliable and inexpensive in upkeep. INDICATOR.
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