Sniper (oz7036)

About this Plan

Sniper. Radio control sport model. RCM pl-984. Jan-87. Hochradel, Hans. Span 37.5 inch. 3-channel. Engine: .051-.10

Quote: "Sniper by Hans Hochradel. A small .051..10 size acrobatic airplane designed for standard size radios.

In flying radio controlled model airplanes, many types and sizes are available. As is normal for me, when the urge came I took to the catalogs and magazines. I wanted a small airplane that fits in the trunk of the car with the wing on the airplane - one that was quiet and maneuverable enough to fly in a schoolyard. Now the problem - I wanted to use a standard size radio, meaning standard size servos and a 550 mAh battery pack, not a mini size radio control. One more thing, I'm not a great flier, but I didn't start in the hobby yesterday either, so the airplane should not look or fly like a trainer. As you probably guessed I could not find anything as a kit, or as plans... so I ventured into no man's land and designed my own. The results are worth sharing with fellow fliers.

Not being a trailblazer (or an aeronautical engineer), I figured that canards, rear engines, multi winged, etc, designs were out of the question. The first question was: What fits into a normal trunk in terms of wingspan, taking into consideration today's 'normal' size car? I figured about a three foot wingspan. The question that follows next is what kind of power is required to move around a maneouverable single winged aircraft with a three foot wingspan? Remember we would like a quiet airplane. My first choice was a .10 to .20 size 4-stroke motor. The size, expense, and power to weight ratio makes the motors marginal for this kind of design. What about electric? Maybe, but I don't know enough about electric. How aboat the Cox .051 motor? Great, but they are annoyingly noisy and, if muffled, they lose a lot of power. Well that leaves a .10 site motor with muffler.

First, I took a large sheet of blank paper and drew in the motor, motor mount, muffler and spinner. The tank for an airplane this size is normally about two ounces. Next, I drew in a two ounce rectangular tank in the centerline of the engine's needle valve. Then I measured the distance of the motor to the wing, and the wing to the tail (normally called moments) on several small airplanes to get the ratio. I added a little common sense and drew in the wing and stab location. This also defines the Center of Gravity. Now that leaves the easy fun part of designing.

I used a fully symmetrical airfoil to keep the airplane maneuverable, and a constant chord wing to keep building simple. The stabilizer is simple sheet stock. The creative part of design is the shapes of the wing and fuselage to create eye appeal. I tried to keep the airplane attractive but relatively simple to build. The wing and stabilizer surface areas were determined by the time tested method known as: looks about right.

Construction. Study the plans and look at the photo sequence instructions provided in the article. After the material list is completed, cut out the various parts. Building is straightforward..."

Supplementary file notes

Article pages, text and pics.

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