Whirling Dervish (oz10371)

About this Plan

Whirling Dervish. Free flight sport helicopter model.

Quote: "Air Trails Parade of Winners - Another National Record Holder. New approach to helicopters is this unique model which established a record of almost 9 minutes. Whirling Dervish, designed and flown by Frank Ehling.

When Mr Ehling started out to better the national helicopter record you could have been reasonably certain that he would come up with a novel model. But no one expected this design which established a new all-time high of 8 minutes, 55 seconds (three-flight total time).

The model shown below, one-quarter actual size, is really a 20-inch propeller which is rotated vertically by small props at its tips. Construction of the lifting surface is similar to that developed by Merrick S (Pete) Andrews for indoor microfilm flying.

Most surprising feature of the Ehling rotor prop helicopter is that the model is extremely stable and with power exhausted continues to float for long periods before descending. The ship is twirled as the propellers are released at start of flight and it climbs at a good rate. In still air the model will land at the same spot where it has taken off.

The same rib form is used all along the wing - the trailing edge is cut down as the rib approaches the center."

Supplementary file notes

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