Eagle (oz11299)

About this Plan

Eagle. Towline glider model.

Quote: "Overseas Glider Design. Eagle Towliner, by Bill Dean.

Latest in a series which started with the Chief (oz9) (S African Nats winner and New Zealand record holder), the Eagle design was finalized after an extensive study of trends and field techniques, which culminated in a visit to the World Championships at Bled in Yugoslavia.

A rugged all-weather layout was considered essential, since the flimsy long-fuselage/small-stab types often come unstuck in anything but ideal conditions. Geodetic surfaces were used to eliminate trim changes occurring in damp or very hot weather - as well as for this structure's unbeatable strength/weight properties. The well-proved MVA 301 section was chosen for the wing, from both constructional and aerodynamic viewpoints. An ultra-simple fuselage was worked out and the frontal area kept to a minimum. Main data was: span 65 in, length 46 in, tail moment 3-1/2 wing chords, total projected area 521 sq in (22.9% stab) and the weight is 14-5/8 ounces.

The first towed flight was made in heavy early morning mist with the model almost out of sight overhead before leaving the 164 ft towline. Time was 3:35 and the only adjustments needed after this were a little stab LE packing and more rudder movement. Subsequent tests have shown that 2-1/4 minutes is an average figure for dawn or dusk flying, which makes this job a contest threat.

Even in near-calm conditions, a dead overhead cast-off is standard procedure - using the rear hook, close to the CG. The climb is very steep, fast and arrow straight. There is no special technique to master, apart from taking care in casting off smoothly. In a good breeze, we tie the towline to our car, release the model as if it were a kite, then stroll back to twitch the line free.

Factors which contribute to the 100% towline stability are correct relationship of hook to CG, adequate underslung fin area, short nose and that essential feature, a positive acting auto-rudder."

Eagle, Young Men, July 1955

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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