Biceps (oz1968)


Biceps (oz1968) by Donald Yearout from American Aircraft Modeler 1969 - plan thumbnail

About this Plan

Biceps. Control line sports biplane, for .60 power.

Quote: "Nearly every airplane nut has a soft spot for biplanes. There is something nostalgic about a two-winger, the whistle of wind through rigging wires and all that stuff.

When our local model club began control-line exhibition flying to stimulate public interest and recruit new club members, I became enthusiastic about a bipe for that type of flying. It would be an attention-grabber, an extremely stuntable and flashy aircraft. The ship I had in mind would be large; a small plane just doesn't get attention. The further I studied the biplane configuration, .the more intriguing it became.

It appeared that the built-in head-wind high-drag characteristic to biplanes might be used to advantage. A large engine to turn a big low-pitch prop would give a very high static thrust. In combination with the high-lift high-drag layout this would result in a relatively slow-flying, extremely maneuverable craft - like a helicopter with its rotor facing forward! And that's the way it turned out.

A few additional design features improved performance, such as: thick, blunt airfoil sections with full-span flaps on both wings to help eliminate the wobbling or staggering at low speeds common to biplanes during tight turns. A large elevator surface proved effective at low speeds. A large rudder with quite a bit of turn-out kept the lines tight at all times, since centrifugal force is not much of a factor at low speeds. There you have it.

The theory sounded good, but the proof came in building and flying the brute. Biceps is a spectacular performer, a real ball to fly. Although not a smooth, precision, contest-type ship, it should give a good account of itself in any contest in the hands of a competent pilot. For exhibition-flying, Biceps is superb, the hit of any show. It is not particularly difficult to build. Large size and straight lines contribute to simplicity. It does take a considerable amount of balsa..."

Update 07/05/2016: Replaced this plan with a clearer copy thanks to JJ.

Update 08/05/2016: Doh. Fixed scaling now to correct wingspan of 48in, thanks to Tri-Pacer.

Update 23/05/2017: added modern copy of article, found online at, thanks to GeorgeAlbo.

Supplementary file notes

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Biceps (oz1968) by Donald Yearout from American Aircraft Modeler 1969 - model pic


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