Electric Challenge (oz7100)

About this Plan

Electric Challenge. Radio control sport model for Astro Flight 25 Cobalt electric motor.

Quote: "Here it is! A mid-size sport flier that's clean, quiet, and still has plenty of performance! Electric Challenge, by Charles Evans.

Having flown .05 and .15 sized motored craft for a time, the need for more power and better handling ability was experienced. I set out to find a 25 sized aircraft to fulfill my immediate need. But alas, nothing seemed to fill the need at the time. Being on this earth for over 65 years and having built models since the age of six, one would think a new design would be a snap. Mistaken. again.

Having a fairly complete collection of model magazines, I began to research for vital information to aid in the design. A list of Do's and Don'ts were compiled. Referring to experts in the field like Bob Kopski, Dr Keith Shaw, Premier Electric Flier, Chuck Cunningham of RCM, Bob Boucher of Astro Flight fame, Mitch Polin. and Dick Gibs, we got started. After all, electrics are a new challenge.

One thing they all agreed with is KILS - Keep It Light Stupid. My model is built to fly rather than crash. Longevity is excellent with the construction presented. Nothing revolutionary, just common sense and good choice of wood graded for use and weight.

Electric Challenge - How Come? Our club, The Martin Marietta Radio Control Modelers of Orlando, Florida, is a great bunch of men. Each doing his own thing according to the club rules and regulations. We kid each other about the

new wave of the future (electrics), greasy kid stuff (engine powered), and that electrics are a new challenge to the modeler. An old, dear friend, since passed on to the Flying Field up yonder, used to say: All things figured right, one can fly a brick. His name was Harry Moyer. His original AMA issue was 193. I picked up the challenge when I decided to turn to electrics, hence the name Electric Challenge.

This model is the fifth in a series of this design and the best to date. Excess sheeting has been eliminated to keep the weight down. The use of lightning holes where possible brings additional weight relief. You may find areas where you can reduce weight, but do not compromise the structural integrity. I have not experimented with carbon fiber or Kevlar, so cannot comment on their contribution to weight loss. Let's get to the construction of Challenge.

Construction. Wing: For no other reason than to get it out of the way, let's start with the wing. Templates are most helpful in cutting out the wing ribs. Mine are made from plywood. Make a template for W1 and W2. They can be used to cut W1A and W2A plus the small riblets that mate the wing to the fuselage. It may be helpful to drive a pin just through the template enough to grab the balsa being cut. Use two, one at the leading edge and one at the trailing edge.

To cut the radius for the leading edge dowel, use a piece of 1/4 OD brass tubing. Sharpen the inside diameter to allow its use as a cutter/punch. Use a small cone shaped stone for your Dremel tool to get the job done. While using the template to cut out the ribs, use the brass tubing to create the radius for the LE dowel. Make a kit of all the components needed to build the wing. Build the landing gear block subassemblies at this time. Now start the wing assembly. Cover plans with your favorite plan protector..."

RCM Plan 1157, the Electric Challenge 25, a midsize sport flier.

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