Stray Tupp. Folding-wing catapult-launch glider model.
Quote: "THE writer 'dreamed-up' the theory for this type of model several years ago, when chuck gliders were in their heyday. Not until recently, however, has the time been available to put it into practice. It has now been proved to operate successfully on the simple model shown here, and no doubt once the principle is grasped, modellers will be able to develop larger and even more efficient versions for themselves.
Now, normally, the height which a chuck glider can reach (apart from when they catch thermals) is rather limited, even when extra force is applied in the form of a catapult. If, however, as on our model, the wings can be folded back, so as to produce zero lift, the model can be 'shot' vertically to a considerable height. The wings then fold outwards into flying position and the model commences its flight.
Building the model. Usual solid glider methods are used - the important part being the wing attachment. The ply mount must be cemented through the fuselage at the exact position shown on plan. The wedge-shaped dihedral-keepers are cemented to the wings and reinforced as shown. 9 BA bolts are used for the swivel attachment, with washers on each side. The wings should swing freely, but not to be extent of being wobbly. The 1/8 in balsa stops fitted on each side of the fuselage will keep the incidence correct. NB The wings fold under the tailplane and parallel with it.
The catch (see plan) and pendulum are made up from 20 gauge wire, the catch being threaded through the two ply bearers before soldering the pendulum on to it.
Now fasten a length of 1/64 in rubber, or similar, at the points indicated on the wings, to pass round the nose, just tight enough to keep the wings in the forward position. Some trial and error adjustments will be necessary to get the exact angle of the pendulum (that on the plan is as the prototype, but will differ slightly with each model). Add weight - in the form of solder - to the end of the pendulum until it is enough to release the wings when the model reaches a slightly nose-down position. It is not necessary to fly the job to find this, of course, the procedure being to hold it vertically, with wings folded and catch in position and gently turn it into its flying altitude. The pendulum should then drop, releasing the wings. Add weight to the nose (CG shown on plan) and trim in the ordinary way, with wings in flying position.
For catapult launch, fold the wings and hold the model vertically with the pendulum catch holding the wings bark. Launch just slightly forward of the vertical, so that the model drops over forwards, and not on its back. This is easily achieved with a little practice. Very good heights can be attained and hours of enjoyment can be had from experimenting with these rocket climb gliders. One wonders, too, if the principle might not be applied to Jetex or even rubber-powered models?"
Quote: "Glider plan and construction article attached. Stray Tupp by D.R. Hughes published in the December, 1950 issue of Model Aircraft found on www.rclibrary.co.uk There were no dimensions given on the plan, so it was assumed that the page in question was the standard 8-1/2 x 11 inch page size."
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