Nordic Tern (oz8394)

About this Plan

Nordic Tern. A/2 towline glider model, with automatic ailerons.

Quote: "THIS year, for the first time in the history of model aeronautics, an International Glider contest is to be held, in which the size of the model is restricted to certain limits. This is something I have advocated for some time, and the Nordic countries, by specifying their A/2 Sailplane class for the 1950 International Sailplane event have, so to speak, taken the bull by the horns.

When the Nordic Contests were announced, I decided that the quickest way to get a model built to this size would be to prepare a reduced version of the Tern II. I found that by reducing all linear measurements by 0.8 the area would just fall into the A/2 class. I further decided to simplify the constructional methods to a certain extent without altering the outlines, and thus the Nordic Tern was born.

This model is not a beginner's model, any more than is a Wakefield in the rubber class, but nevertheless there is nothing difficult in its construction. A tip-up tail dethermaliser actuated by an Elmic timer is used, a further feature being the auto-aileron device causing the model to circle after casting off from the towline. A small hardwood peg holds the aileron in the neutral position while the sailplane is being towed up, this peg being connected to the tow ring by a short length of thread. At the top of the launch, as the tow ring is released the peg is pulled out and the aileron tips up, causing the model to circle without losing trim as is usual with an automatic rudder.

Fuselage. It is here that I have departed from the design of the Tern II, and a crutch system is introduced. The crutch forms the lower longerons of 1/8 in square, with spacers and a front portion of 1/8 sheet cut to shape. Formers are then cemented into position. Cut out two sides from 3/32 in medium sheet (a join will be necessary as the length is more than 3 ft, the usual size obtainable). Cement the top longerons onto the insides of these sheet outlines. Offer up each side in turn to the crutch with the formers in position.

Without removing the upper fuselage from the board, all other items can be added - wing box, centre section, fin and tailplane platform, etc, at the same time keeping careful check on measurements regarding incidence, etc. The Elmic timer and actuating wire are fitted, and finally the top is sheeted in with 1/16 sheet.

After removing from the board, the ply keel complete with tow hooks is added, also nose block and lower formers. The rear portion is then covered with 1/16 sheet. Balsa block is cemented to either side of the keel and carved to shape..."

Scan from DBHL, cleanup by theshadow.

ref DBHL-5235.

Direct submission to Outerzone.

Update 05/02/2017: added article, thanks to RFJ.

Supplementary file notes

Article.

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