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Aviation History
1912
1912 - 0335.PDF
Conducted by V. E. An Entirely New Recoid. ON March 31st last, early in the morning (about 7 a.m.), Mr. H. H. Groves (of the Blackheath Aero Club) was successful in setting up an entirely new Model record, and one which if we are not much mistaken, will have some far-reaching consequences so far as models are concerned, at least. The record was made with a steam-driven model (up to then untried in actual flight), of a some what similar design to that recently illustrated in FLIGHT, but fitted with a more powerful, or, to speak more correctly, a more lasting generating power plant, i.e., one having a longer duration. Mr. Groves writes as follows: " The weather was just good enough [to risk trying it] and no more. I was unable to let the engine have more than ii-oz. of water [owing to ground JOHNSON, M.A. New Cross, S.E. ; as well as a policeman whose address is known, and a passing spectator whose address was not taken. Mr. A. B. Clark forwards us the following account : " I arrived on the ground about 6.10 a.m., and found Mr. Groves preparing his model. The first flight was as follows : " Taxied " about ao yards, and then rose very steadily to about 15 ft., and flew approximately 150 yards. The next [i.e., the third atiempt] flight was a short one, a sharp circle to the left. The third flight i.e., the fourth trial] commenced after a run of 8 to 10 ft., directly facing the wind—now blowing 16 to 18 m.p.h., the model starting to climb at a very good angle—faster than Hamel on his 50-h.p. Gnome- Bleriot—until it reached about 120 ft. It had then travelled some 150 yards into the wind, after which it turned down wind, and passed us at a good altitude, and finished up 220 yards away from the start, so that it had travelled something like 500 to 520 yards altogether, i.e., 150 twice plus 220. It finished up with the finest volplani I have ever seen except on one occasion. Mr. Groves is to be congratulated on the results obtained." [A sentiment which we heartily endorse.] Mr. W. R. Halman writes : " I have read the enclosed letter by ' SO YA*J5£, Mr. H. H. Groves' steam-driven model in lull flight. Notice the fine banking exhibited by the machine. conditions; the full load is 4 02.]. The first flight was perfectly satisfactory, the machine leaving the ground after a run of about 12 to 15 yards, then rising gradually to some 12 to 15 ft. and then slowly falling in an accelerated glide as the propeller thrust fell off and landing perfectly with the engine still running slowly ; nothing like full pressure had been used in this flight—which partook of the nature of a preliminary character. The length of actual flight was about I50 yards. The next run proved a failure, the engine not having been given sufficient pressure, and the model finally stuck in the grass. The third attempt was completely successful, the model rising in about 4 to 6 yards and executing a circle of about 50 yards radius (i.e., a flight of some what over 150 yards), banked well during flight [see illustration] and finally landed quite safely, still banked to angle of about 30 degrees. The wind was now getting up, but I thought I would chance one more flight with ij-oz. of water [amount of benzoline used ij-oz.]. The engine this time was given more pressure—the valve being opened full—with the result that the model rose after a run of 8 to 12 ft. only, facing the wind, and mounted steadily up to about 100 ft., in 15 to 20 sees., and made a flight 220 yards from the starting point. Since the model faced the wind to start with, and made at least some 50 yards headway previous to turning—taking all this into account this means, at least, 350 to 370 yards. The total weight of the model including IJ ozs. of water and 1J ors. of benzoline was 3 lbs. 11 ozs. The climbing was all that could be desired. The engine and propeller make a noise just like a full-sized machine in the air. In addition to the photograph which we publish, Mr. Groves forwarded another (which, unfortunately, will not bear reproduction), taken when the model was high up, from this photo, combined with the focal length of his lens and certain well-known properties of light, he deduces the height as not less than 100 feet, a result with which we quite agree. The actual photo reproduced was taken during the third trial (the circular flight). Exposure, Toff sec. Time of day, 7 a.m. Stop. F. 11. Imperial special rapid plate. The following, besides Mr. Groves and his brother-in-law were also witnesses of these flights: Mr. A. B. Clark—a well-known aeromodellist — hon. sec. Blackheath Aero Club; Mr. W. R. Halman (Glanmire, co. Cork); Mr. G. Brown, 20, Vance Street, fNGINt STOPPED rl * ;6LIDE: FROM RBOUTRO I k——— --M Mr. Clark re Mr. H. H. Groves made), which is correct in every detail, and I can corroborate the same." Naturally, personally speaking, we are deeply interested in these results, the type of plant being one which we have advocated for some considerable time, and one with which we are personally experimenting with the most successful results so far as all bench tests are concerned. Only on March 30th (with the plant already referred to in these columns) a thrust of no less than 2 lb. 10 ozs. was obtained, sufficient, according to Mr. Groves' results, to launch and fly a 8 lb. model, whereas the one which it is destined to fly will weigh but slightly more than three. In the flash-boiler ty]>e we have ample power, and we are fully convinced now that it can be successfully applied to much smaller models- weighing, not 3 to 4 lbs., but 1 lb. only, or even less. At the same time, the reader must not draw the erroneous conclusion that we consider this type of power plant, as yet, to be possessed of a really high degree of efficiency —roughly speaking, we should put it on a par with the rubber motor previous to the introduction of lubrication. One cannot help contrasting the results obtained with IJ oz. of water and ii oz. of benzoline, total 2% oz., and a machine weighing 3 lbs. u oz., with what the same weight of rubber, i.e., 2f oz., could do with the same machine ; weight of rubber : total weight of machine : : II : 236, i.e., approximately, I I 21. The weight of the material necessary to develop or set free the energy contained in the benzoline, &c, is considerable, being in this particular case about I lb. 10 oz., whereas in the case of rubber all that is required is the stick or motor rod. The entire model was designed and constructed throughout by Mr. Groves. The greatest difficulty in connection with power-driven models is a suitable ground on which to try them to their full capacity with any feeling of safety ; it is not so much a question of bad landing, as of trees or other obstacles ; also pools of water or small lakes into which the model might fall. It is all very well to say set the rudder or warp the wings so that the model will circle, in the case of three or four minutes' flight; even on a comparatively speaking calm day, there is the question of drift to be considered, and if there is anything nasty knocking about the model is sure to find it. Another half-an-ounce of water only in Mr. Groves' last and best flight would have landed his model in serious difficulties. 335
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