MODEL AEROPLANE NOTES

Auckland Star, Volume LXX, Issue 29, 4 February 1939, Page 3 (Supplement)

MODEL AEROPLANE NOTES

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AN INDOOR MICROFILM MODEL. Fitted With Wheels or Floats. Here is a little indoor model which, though reminiscent of the Clarkson Baby EOG published about two years ago, has many line points and is quite suitable for the beginner in indoor work. Admittedly one must have* a very light. touch for this class of construction, but this model is not all so super-light 1 that it should cause any great trouble j to the builder of average ability. "We have not seen much indoor Hying up j tin's way for the last year or so, and if the Dominion club champion cup is to come back to Auckland it is time some of the younger members started their indoor machines. |

As a hydro model, this one will take off the small tray usually provided and fly strongly. It has done over 7 minutes in this manner in a hall with a ceiling of 35ft.

As far as the construction is* concerned, pick out your class of balsawood rather carefully, as it will have a great bearing 011 tlie performance of the finished job, and if you stick to the given grades you will he right on the way to success. The spar is the usual streamlined section hollow tube of £in grained l-(J4in balsa sheet. Jt is bent round an £in rod, the two ends brought together and cemented carefully. The ends arc capped with l-32in sheet balsa, as plainly shown in the drawings. The wire fittings arc made from No. 27 swg wire and cemented .to the spar. It will be noted that the tail-boom is tapered from 1-1 Uin to l-32in, and a tip here may be useful. When sandpapering small spars like tljis, always stroke the abrasive paper away from you—never towards you, or you will certainly break the very light structure.

Both the rudder and the elevator are made up first in skeleton form attached to the tail-boom and covered with microfilm later. The rudder is a single length of 1.32 in square balsa bent round to the requires curve and is quite flat in section. Xote that the elevator has a definite lifting section. The elevator tip,?, fine out to l-(>4in. Fine work, but by 110 means impossible after one or two tries. The tail-boom, with empennage attached, is cemented to the main spar so that the end' is elevated •«in and is also ofFset -}iu to the left, thus allowing the model to circle with tlie torque.

The floats (if desired) are made up •from # l-32in square balsa strip, covered with superfine tissue and doped with banana oil. The struts for the floats arc 3-ti4in square sanded round, and attached by cementing at the angle shown. The wing struts are the tame size. It is quite important to watch the angle the floaty make with the water, so take care of this or you may have trouble with the take-off"

The wing is very simple, the main thing being to get the ribs all made to the correct camber. It is usual to make a metal template and. laying it 011 the sheet balsa, cut. all tiie ribs exactly the same and then trim off to suit the taper. As all sizes are well and clearly shown in the drawing, it is not necessary to refer to them again here.

The propeller is carved from .1 piece of very soft balsa, 7Mu by Uin by gin and using a 12in loop of l-lGin by i-30in rubber for the motor. The weights of tlie finished parts are as follow:—Winer, .OOooz; propeller, the same; motor stick, .004oz; tail surfaces and boom, ,002oz; floats and struts, .003oz. Rather delicate parts, but surprisingly sturdy when tlie whole job is constructed.