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Aviation History
1915
1915 - 0017.PDF
JANUARY I, 1915. A really satisfactory compressed-air motor should, when set at the dead centre and the tap turned on, show no sign of leakage even when tested in oil. The autoplan motor referred to below does not fulfil this test, although, considering its original price, it is un doubtedly a very good motor. There is no doubt there is a good opening for a simple, cheap and efficient motor capable of giving a 6 to 8 oz. thrust at a pressure of about 110 lbs. and suitable for flying a compact model of the biplane type, of a total weight of about a pound. (To be continued). The " Autoplan " Compressed-Air Plant. Mr. A. G. Boniface (Wimbledon and District Model Aero Club) sends us the following very interesting communication with respect to the above plant, similar to the one shown on the Bragg-Smith model :— " Referring to your article on models driven by compressed air in last week's issue, I am able to give a few particulars of the AIR CONTAINER AND THRFAD FOB FIXING PUMP ' Autoplan' compressed-air plant. The weight of the motor, including the front shaft, bearing and the throttle, is 3^ ozs. exactly, and that of the container just under \o\ ozs., which also includes the engine mounting and wire cabane. Thus the complete plant weighs 14 ozs. " The weight of the ' fuel' in these plants forms another interest ing question. Sixty pumpstrokes of the pump which is supplied with these machines turns the scale at exactly h, oz. The average number of strokes given to a container for each flight going ' all out' is about 210. Thus the compressed air adds approximately if ozs. to the weight of the machine when empty. " That the weight of this plant is not by any means excessive considering the power developed is shown by the following test. The weight of my own model is 27J ozs., or a good 29 ozs. when pumped to the above number of strokes (pressure about 145 lbs. AFFILIATED MODEL CLUBS DIARY AND REPORTS. Club reports of chief work done will be published monthly for the future. Secretaries' reports, to be included, must reach the Editor on the last Monday in each month. Paddinsrton and Districts (77, SWINDERBY ROAD, WEMBLEY). Monthly Repo?-t.—During the past month very little flying, the only work of note being trials by Mr. A. Rasmussen with a twin-tractor model. Several flights were made, but the stability of the model appeared to suffer from insufficient fin area. On Dec. 12th, a special general meeting was held at 77, Swinderby Road, Wembley, when a discussion on reseatch work and the best means of carrying it on was introduced by the secretary, who pointed out that the lull in competitions owing to the war gave members an opportunity which should not be lost of doing other important work. It was pointed out with emphasis that models for purposes of research work must be well con structed, and in particular fuzelages and planes should be rigidly built. The weight of such models would necessarily be slightly more than the usual run of record breakers, but this would be amply compensated for by the results achieved. Some of the subjects outlined for investigation were:—Propellers: Their diameters, width of blade, and pitches. Planes : Angles of incidence and cambers. Fins: Areas and positions. Air Currents: Streamlines formed around various objects. Flying speed of different types of models, measuring speed whilst in actual flight. Before concluding the meeting, the secretary explained by means of diagrams on the black-board the principles of the Merrill staggered converging biplane, an aeroplane with neither elevator nor tail. A sketch of a new plane was also shown, its two-fold object being a high lift/drag ratio com bined with insusceptibility to side gusts. Some of the problems introduced at this meeting will be further discussed at the annual general meeting in January, of which members will receive due notice. Southwestern Aero Club (373, BRIXTON ROAD, S.W.). JAN. I6TH, competition on Brockwell Park at 2.30 p.m. for enclosed tractors (rubber enclosed). Monthly Report.—Owing to the preparations for Christmas things have not been very brisk. Several machines are in course of construction for the com petition on Jan. 16th. The result of the target contest was disappointing, in spite of the fact that the weather was anything but unfavourable. At a n-eeting on the evening of Dec. 12th, it was decided to award Mr. F. Miller's prize to Mr. S. Smith and the club's second prize to Mr. J. Reid. Stony Stratford and District Kite and Model Ae.C. (OLD STRATFORD). JAN. 6TH, monthly meeting at clubroom. Jan. 2nd, December competition, at 2.30. Jan. 16th, January competition, at 2.30. Monthly Report,—At a members' meeting, held Dec. 2nd, the subject was " Frame Tests." The annual report and balance sheet were Tead and passed. Attention was drawn to the absence of protectors at the last competition, it being resolved to strictly enforce the rule relating to the same. Arrangements were made regarding the club sales of materials, &c. Correspondence was read from the Scottish Model Ae. Club, and their trial of our club competition rule. It was decided to collect from members only for one wing of the air service. per sq. in.). When held vertically with the engine running 'all out' the model rose easily, and would have come into rather violent contact with the ceiling had I not held on securely. The thrust was sufficient to hold the machine vertically for a period of about \ of the useful run of the motor, 25-30 seconds. The tractor used was a I5j-in. Chauvicre type of 23 ins. pitch. Incidentally visitors to Wimbledon Common during the last few months have probably noticed that one of the outstanding features of the com pressed-air models was the manner in which they climbed at the start of a flight." With regard to the foregoing, the Autoplan plant is, of course, of German origin, and can no longer be obtained in England. Messrs. A. W. Gamage, however, inform us that they are putting a similar motor on the market at 12s. 6d., and have promised one for our inspection. The price of the German motor was Js. 6A Mr. Boniface's information with respect to the increase of weight with increase of pressure is especially interesting ; it is this and similar kind of experiments that are so much needed. Desiccated Air for Compressed Air Motors. Mr. O. Hamilton, Junr., writes as follows with respect to the above :— "With reference to your article on Compressed Air Motors, my father and I have been discussing the subject, and I mentioned the fact that you proposed making some experiments with reference to heating the air in the container, and in the course of our conversa tion he said that the best way to use compressed air was to use it 'dry,'the drying being carried out by using a filter charged with a desiccating substance, the air being blown over this as it is charged into the container by the pump ; the air being dry will not on its expansion cause such a rapid fall of temperature as it does not absorb such a large proportion of moisture in the operation, and hence will not freeze. •' I am offering the suggestion of drying as a possible means of a light and handy method of experiment." [The question of freezing of course depends very largely on the extent to which the container is charged.] Aeromodellists Serving with the Colours. Amongst aeromodellists at present serving with the Colours one of the test-known and most successful in open competitions is Mr. Leonard H. Slalter, of the Wimbledon and District Model Aero Club, who is at present in the armoured car section of the Royal Navy Air Service. ® ® Will members who have promised please forward their contributions. Regular weekly flying has been impossible, owing to the rough winds, wet, &c. On Dec. igth, Mr. Mennell turned up with a hollow-spar diamond shape, the first built in the club and by this member, which did credit to its builder. The weather was very rough, and at first the machine was underpowered, but making good this deficiency, he obtained 51 sees, and 280 yards, when the machine landed in the road and, unfortunately, the kind Samaritan who picked it up, in putting it over the hedge, broke the main plane. The I )ecember com petition was postponed till Saturday, Jan. 2nd (to-morrow). Hrown reports no sees, from a bench test of one of his singles, so we expect a little movement shortly. Wimbledon and District (165, HOLLAND ROAD, W.). JAN. 2ND AND 3RD, flying as usual. Monthly Report.—There has been very little flying during the past month owing to the inclement weather which has prevailed. Compressed Air Models. —Messrs. Boniface, Tucker, Chown, and Hayden have flown c.-a. models. Mr. Boniface's monoplane has been flying in its usual good style, doing durations up to 35 sees. Mr. Tucker's Avro has been out on several occasions, flying very fast at a good height. Mr. Chown's tractor-monoplane has been out twice, the best flight being one of 32 sees. The first trials of Mr. Hayden's new machine took place on Wormwood Scrubs on the 27th. Two flights of 35 and 39 sees, respectively were obtained. In the second flight the model reached u height of over 150 ft., but owing to the collapse of a strut a nose-dive brought it down at a very steep angle, doin^ some damage to the forward portion of the fuselage. This, however, will be repaired, and the machine will be out again next week. Rubber-driven Models.—Mr. W. G. Smith has flown a small fast twin-screw doing Ion*,1 distances. Mr, Powell and Mr. Chown have flown 3-oz. twins. Mr. Hayden has occasioned great excitement with his tiny Sopwith scout, which performs most agreeable stunts. UNAFFILIATED CLUBS. Ffnsbury Park and District (66, ELFORT ROAD, HIGHBURY, N.). JAN. 2nd, 3 p.m. Distance and duration contests (h.l. all types) prizes value 4.V, Ctt. and carved propeller presented by secretary. Monthly Report.—There has been much less Hymn this month chiefly owing to the inclement weather experienced. Mr. F. E. kaynor who has previously been addicted to twin-screw machines, brought out a tractor of the Morane type which acquitted itself well. Other members flying include Mr. G. Wren (Morane), B. H. Barnard (Morane), A. Richards (Deperdussin), H. Mullin (Morane), A. Savage (Antoinette). AH machines this month have been tractors and monoplanes. Liverpool Aero Research Club (62, CBDAR GROVE, LIVERPOOL). ALL model flying during January to take place at Clubmoor, Saturdays at 2.30 p.m. prompt. Discussions: Jan. 13th, at 62, Cedar Grove; Jan. 27th, at 22, Eton Street, 8 p.m. prompt. Monthly Report.—Wretched weather has interfered greatly with model flying, one competition having to be postponed twice, whilst Dec. 5th, 19th, and 25th were blank days. On the 12th, despite a gale, Tear, Bennett, and Kilshaw turned out with r.o.g. biplanes. F. Lowe has had out a fine racer, which in spite of this period of gales made some good flights. On Boxing 1 Jay a good attendance was recorded, when the r.o.g. duration competition was held '7
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