Cannonball (oz4406)

About this Plan

Cannonball. Radio control model. An .020 powered micro midget pylon racer. Design by Bob Aberle.

Quote: "The April 1976 Flying Models carried my product review of the Cannon Electronics, 'Tiny Series' R/C equipment. It was only natural at the conclusion of this review that my thoughts, turned to the possibility of a new design, expressly intended for this extremely small radio unit.

As I went back over approximately ten years of model publications. covering 1/4A (the usual terminology for the .020 displacement engine), I found that the majority of these designs were built around the simple pulse proportional type radios utilizing magnetic actuators to move the control surface. This type radio system is very light, but limited to single channel opera-tion, for the most part. Some individuals did manage to rig up coupling schemes to include elevator control as a second function, but by in large these techniques left plenty to be desired. A good many of the designs had high aspect ratio wings which put the model in the category of a powered glider.

Another item which caught my attention was the continual reference to the need for throttle restriction on the Cox TD .020, simply because the power output was too great for the radio control unit to handle. What a terrible waste of a good little engine, such as the TD .020.

After completing my 'literature' search, I settled upon a wing area of 125 sq. inches, a wing span of 22 inches and an average chord of 53/4 inches. The wing aspect ratio of 3.83 is a little higher than that presently used on the .049 size, 1/2A R/C pylon racers. Since most of my R/C flying time of late has centered around 1/2A pylon racing, the influence is obvious in this new design. Because of the fact. that I had two digital proportional channels available I naturally selected a flat wing with aileron control. It is basically the aileron/elevator control which makes this design stand apart from its predessors. A wing with dihedral, using only rudder and elevator control, is simply a trainer, any way you look at it. The Cannonball is definitely not a trainer. It has full performance capabilities and should not be considered as a project for a first R/C model.

One of the big considerations in a design as small as this is the weight factor. I set up a design goal of 11 ounces total weight, less fuel. Surprisingly enough I almost hit this target weight, the end result being 11.8 ounces. The basic weight breakdown is as follows..."

Update 04/05/2016: article pages, text & pics added, thanks to RFJ.

Supplementary file notes

Article pages, text & pics.

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