Mousetrap (oz2786)

About this Plan

Mousetrap. Free flight gas model. For .29 cu in engines. Wingspan 54in, wing area 340 sq in, flying weight 24oz.

Quote: "Though not so-named because it snaps onto thermals, Mousetrap nevertheless will do just that. Mousetrap, by Don Justice.

DO YOU crave a change from pylons? Well, here is Mousetrap - it will perform with the best of pylons but doesn't look like one. The author doesn't intend to enter into the old pylon-versus-shoulder-wing controversy, being more or less an old pylon man himself. But Mousetrap, with a completely cowled-in motor, has an advantage in streamlining yet doesn't give up any stability or ability to handle high-powered motors. It has a good contest record, too, having made at least one out-of-sight flight at every contest it enigered. Its best time to date is a 31 min official turned in at Clarksburg, W. Va, on a perfect flying day.

Mousetrap is a high performance Class B contest model. It was designed for 0.29 cu in motors and is as compact and light as the rules allow. For this reason it is not an ideal model for just sport flying, as most motors will not turn slowly enough to keep it from climbing pretty high, and its glide makes it the prey of most any old thermal. If you want a sport model it is advisable to substitute larger wheels and beef up the construction so as to add weight.

You might be interested in the whys and wherefores of the design. The author wanted a good contest model, and the design was worked out from this viewpoint. The most important factor, then, is stability. A model that is stable will handle the power of the most hopped-up motor, will be easy to adjust, and will perform well consistently. Stability requires a balanced arrangement of the aerodynamic forces. Generous horizontal tail area gives Mousetrap a good margin of longitudinal stability and permits the Center of Gravity to be located back toward the wing trailing edge. This CG location helps the glide by causing the ship to assume a fairly high angle of attack in the glide, yet the ship keeps its nose down in the climb without use of downthrust.

Spiral stability was built into the ship by strik-ing as good a balance as possible between the amount of dihedral and size of the rudder. With the CG in the location shown on the plans, the ship has no tendency to tighten up into a turn in either direction under any amount of power. The author would like to point out here that spiral stability is a combination of lateral and directional stability..."

Update 29/03/2014: Replaced this with a clearer copy at full size, thanks to JJ.

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