MODEL AEROPLANE NOTES and General Hobbicrafts

Auckland Star, Volume LXVII, Issue 151, 27 June 1936, Page 3 (Supplement)

MODEL AEROPLANE NOTES and General Hobbicrafts

by Propeller

MODERN SAILPLANES.

In those columns I have often referred to the fact that aviation in general is indebted to the work of the model maker to a great degree, briefly because it was the early experimenting »ith models that gave the pioneers of the industry many ideas, and in a lot of cases taught them their first lessons in the science of flight. This is no less true to-day, for models of intended machines are made by expert craftsmen and submitted' to wind-tunnel tests. In these tests the models are suspended or held in such a. manner as to allow very delicate instruments to register exactly the effect of each manoeuvre. By this means many of the "bugs" can be taken out of an aeroplane before it is ever built, a saving of much expense and time, and undoubtedly a saving of human lives. Then we pass on to gliding and sailplaning. I know that most of my readers will not need the following explanation, but many people have such hazy ideas on the subject that I want to carefully explain what I am talking about. A model aeroplane is usually from one to four feet across the wings and generally driven by a skein of rub-

ber threads attached to the propeller hook in front. The propeller is wound up in the reverse direction and when allowed to rotate freely, by reason of tiie power stored in the rubber, it turns the propeller in the required direction, and the pull of the propeller, aided by the lift derived from the wing of the model, causes it to fly.

Other models are driven by other sources of power, compressed air being sometimes used, and lately we have been seeing some very fine large models of 8 to 10 feet wingspan driven by tiny petrol motors. From all of these models great lessons in aerodynamics can be learnt, and the hobby calls for real brains, and I know that the average model builder is very annoyed when someone thoughtlessly calls his model a "toy aeroplane," and in my opinion rightly so, for hidden behind the actual sport derived from flying them is a wealth of scientific preparation.

Now, gliders and sailplanes are large man-carrying machines, in most eases of a greater wing spread than the Moths that you see flying around your local aerodrome. Not having engines to propel them they rely on, in the first instance, taking off and living down a gentle slope, and later as we progress to sailplanes, to soaring for many hours in tlio uprising currents that are to be found over certain contours of the country. A great affinity exists between models and gliders, for it is by experimenting on the former that bettei results may be obtained from the latter. And still a greater affinity exists between gliders and sailplanes, and power machines, for from the lessons learnt in constructing and flying gliders we hope to evolve that "hundred pounds light aeroplane for the masses. J.he great designers in Britain, Germany and America are working hard on this idea, and we will undoubtedly see it come to pass very shortly. Last season the Auckland Gliding Club registered well oyer GOO flights, and were just on the point of having enough members expert enough to starting thinking of real soaring flight, when the disastrous gale in February just about wiped out all the club's property. However, they are now in the possession of a completely ready Waco glider and a Zogling training machine which, is practically finished and ready for co\ ei - in it. Incidentally, the members of the club are gathering a great deal of valuable experience in aircraft construction during the progress of this work, and they will come on to the field with a better understanding of the glider the} will be flying in. _ . The plan which I am giving you this week is one of the new English sailplane, the Cambridge. This is now recognised as one of the finest of its type" with great flying qualities, and its relative simplicity of construction will appeal to builders. The fuselage is fully streamlined and covered with light aeroplane three-ply. The main wing is of the single spar type, with plywood leading edge, which gives great strength combined "with lightness, and resists torsional strains admirably. The balance is covered with doped fabric. Here are some specifications. Span, 40ft 4in; length, 21ft 4in; max. chord of main wiiig, 4ft 2in, tapering at the ends. The wing area is 100 sq. ft, and the weight 2501b emptv and with pilot up to 4501b. Wing loading, 2.811b per .sq. ft; stalling speed. 25 m.p.h.; minimum sinking speed, 35in per second; flying speed 45-50 m.p.h. I think that this would make quite a good model for the modelling section, and the sizes and specifications are very interesting, in view of the fact that we have up until recently been in the habit of thinking that the Germans were the only people that could build high-grade sailplanes.

SOARING FLIGHT IS BECOMING MORE POPULAR.

Club News. The Auckland Model Aeroplane Club reports consistent enrolments, the club .roll now standing at over 70 members. The Kealey Cup competition for flying points gained stands as follows: W. 13. Mackley 85, D. Arnold 05, R. E. Allen 55, A. F. Martin 55. The club ladder points are as follows: W. B. Mackley 19, R. E. Allen 17, A. F. Martin 10, E. Rose 14. The Garrett Shield for the month was won by D. Arnold. The free dual control flight, given monthly by the Auckland Aero Club, was awarded to A. E. Martin. Recently Flying-Oflicer P. B. Lusk visited the Friday night clubroom meeting, and gave an interesting talk on his work with the R.A.F. on the North-west frontier. A wonderful collection of photographs were appreciated greatly by the members, and Flying-Ollicer Lusk stated that ho had never shown these to a more appreciative audience, the members surprising him considerably by their great grip of the subject. Harry Reynolds is to be congratulated on his movie film of club doings, and the members had an opportunity of '"seeing themselves as others see them,'' the launching, flying and incidental handling of the models outdoors being remarkably clear. The petrol model flights were included, and certainly make history for the club.