About this Plan
Krackerjac. Single channel R/C trainer model for .15 power. Later kitted by Jetco.
Quote: "Single-Channel Radio Control Plane Fly's Like Proverbial Dream. Krakerjac, by Bill Winter.
Versatility is the keynote in Crackerjac's design. For single-channel operation with rudder-only or rudder-and-throttle control, it is adaptable to training. sport, or more advanced flying. Its special airfoil affords excellent performance in the wind.
Exhaustive flight testing of four airplanes with various engines in the .09 and .15 categories permits precise recommendations on power and trimming for performance matched to the operator's particular skill and demands.
In the .15 airplane this objective is not easily attained. A typical .15-powered machine spans in the neighborhood of 48 to 54 inches and has a high if not troublesome rate of climb which can be disastrous in the wind. However, its performance wins contests in skilled hands. Unfortunately, many of us do not have experience to cope with difficult fast-action situations. For training, a .15-powered airplane should span about 60 inches (none exist!), but of course it would be unsuitable for people who wish to burn up the sky.
Plans for Krackerjac show a 'de-rated' version for safe sport flying. For the experienced pilot who prefers a hotted-up affair, simple changes are outlined here. In brief, the 'tame' configuration calls for one of the lower powered 15's, a center of gravity location closer to the leading edge than is normal, with a larger decalage - angular difference between wing and tail - than is common practice.
If this version is built and no throttle is fitted it is essential to avoid powerful engines. It is recommended, though not imperative, that a two-position throttle be installed. Plans illustrate a Cobb Hobby three-position motor control escapement with a torque rod to old-stvle Roto-Valve throttle. We also tested a vertically mounted Bonner SN escapement with a push-pull linkage to the new-style Roto-Valve throttle on the K&B .15 (the previous one!). If the K&B is used, the radio installation will have to be on the right side to clear the motor-control push-rod. Ideal results will he obtained by setting this throttle to give high and medium power, rather than high and low motor..."
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