FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1917
1917 - 0099.PDF
r JANUARY 25, 191-. A " Triangle " Plane. FROM Lieutenant C. C. Horner comes the accompanyingphotographs of models which he made while serving in the R.F.C. some time ago. They are improvements on theC.C.H. triangle plane which he originally designed in 1909. thrust on screw as before, but the results being vastlydifferent, only getting 20 yards at about an altitude of not more than 3 ins.—-uiore like a grasshopper than anything.Most likely the camber has a lot to do with it, but the thing is what has it to do with it ? ' , Two triangle plane models with which Lieut. C. C. Horner has been experimenting. 1 The pusher type flies from 200 to 300 yards, while the tractor does about 100 yards and is very stable.A Scale Model. In sending along the two photographs, reproduced herewith,of a model tractor biplane, which he lias designed_and con- structed, Mr. E. H. Hammond gives the following particulars : The measurements are : Length of main planes, 24 ins. ;gap, 4 ins. ; chord, 4 ins. ; length of fuselage, 18 ins. It has also a model Gnome seven-cylinder engine, and also work-ing controls. The only tools used were a fretsaw, drill, and screwdriver. [Mr. Hammond asks for criticism on his work, and certainlyfrom the photographs it appears that his model is one Of the " I will now take my second question. This relates to'highand low centres of gravity. " Where should a model balance in relation to the line ofthrust either of a biplane or monoplane ? Should the centres be above the line of thrust or below, and how much above orbelow, that is, to take the machine by the inside struts and balance so that the planes point up and down, not horizontal." Jicply.—1. " Eiffel's Resistance," &c, gives characteristics ofvarious wing-sections. This book can be seen at the leading public reference libraries. The smaller camber in the secondmodel would not necessarily be tli£ sole cause of the poor performance, as by reducing the loading and camber youhave called for greater speed than before to obtain the Two views of a scale model biplane made by Mr. E. H. Hammond. best scale models we have seen for some time. The propor-tions are very good and the design up-to-date, while evidently- great care has been taken in the workmanship.]Replies to Queries. Mr. F. J. Mabb, of Leeds, writes :—" Could you give anymethod to work upon relating to certain cambers and the amount of lift derived from various curvatures withoutresorting to wind-tunnel tests, an article, I am sorry to say, I do not and cannot at present afford to possess ? " We all know that a cambered plane lifts much betterthan a flat one, the general rule being to load a model at so and so, but if one knew exactly what work was being doneby, sav, a plane of a small curvature and another of a deep camber, it would help'one on with the study of aeronautics. "I will take a point in question. Two years ago I con-structed a scale Blackburn monoplane which was loaded rather heavily, carrying 12 ozs. to the square foot, but flewremarkably well for a scale model. I believe the best flight was close upon 100 yards r.o.g.; the span was 3 ins. witha chord of 8 ins. The camber here was J in. at the deepest point situated one-third from the leading edge, planes doublesurface. Now I make another machine with improvements, and load it at 8 ozs. square foot, with a span of 42 ins. andchord of 61, the camber here being J in. at deepest pofnt situated in the same position as the first machine, same necessary lift for the same propeller thrust. You mightobtain good results by increasing the thrust, or, should you require a slower speed, by slightly increasing the camber.In any case, the camber should be kept as small as possible on models, no advantage being gained from big cambers. 2. Generally speaking, it may be taken that the centre ofgravity should coincide as near as possible with line of thrust, anything above the line of thrust. Mr. N. Kingsley-Pallant writes :-•-" In your issue of" FLIGHT " dated September 7th last, you described, verybriefly, the Sharp 3-stroke petrol engine for models. Would you be kind enough to send me a few further details? Theapproximate horse-power, diameter of propeller supplied, overall height, and greatest length of engine, &c. Also, canyou tell me if a rigid airship jnade of wooden formers and hoops (approximate dimensions 12 ft. long x 18 ins. greatestdiameter), ha\-ing a capacity of about 20 cub. ft. of hydrogen, should have sufficient lift to take the weight of this engine,and if the engine would be powerful enough to drive 11 ? " Reply.—H.p. of engine about i| ; height and length about6 ins. x 31ns.; propeller not supplied. Further particulars can be obtained from A. W. Gamage, Holborn. As 20 cubicfeet of hydrogen would lift only about ij lbs. you could nol employ this engine, which weighs about 1 lb. 15 or., complete.1,000 cubic feet hydrogen lifts nearly 70 lbs. 99
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
