Sunday, March 25, 2018

RC Modeler's Yardstick

A model made completely of surplus yardsticks

 This model was so large that it makes the Quadra 40 engine on the nose resemble an 049.

RCModeler's Yardstick

Plan 910.

Type Model RC Sport Trainer.

Wingspan 108in.Highwing.
Engine Glow Fox .60
Control 3 channels.
Designer George Thompson.
Magazine RCModeler Apr.1984.

The wing was made up of 2 - 6 foot panels joined at the center and supported by two struts made from tent poles. To watch it drone overhead you almost could image that it eclipsed the sun. Actually the model was designed to fly on a healthy sixty size glow engine. I flew this plane at first with an Eagle 61 Fox engine driving a Byron propeller speed reducing apparatus swinging an 18 X 6 inch propeller. This prop was much too small for this power setup; even at full speed the model would catch up to the engine and the thrust dropped off accordingly. The result was, after takeoff the planes altitude could not be increased to much more than a couple of wingspans above ground level.

I remember that first flight very well: how scared I was at the time frantically attempting to negotiate this big beast around the field. The flight ended when the engine power began to sag and the forced landing was made in the rough off the runway. The cause of the power loss was abundantly clear as soon as we approached the downed Yardstick. The high revolutions caused the screws holding the cylinder to the crankcase to loosen to the point that the members were on the verge of separating. The problem could have been solved with a bigger and higher pitch propeller but as I recall I couldn't bring myself to spend thirty dollars for a propeller that may have lasted no more than a flight or two.

One day while flying the model with the large Quadra 40 Gas Engine installed, it suffered a nasty accident when it was caught in a tail wind and hung vertically by the propeller. Foolishly I immediately reduced power, instead of trying to power out of the problem and it settled heavily onto its tail feathers. In the end this was the final straw for my old Yardstick, not worth repairing and too large to store in my limited hanger space.

Yardstick Plans

Get all the details by watching the video below.

1 comment:

  1. Interesting post, the first time I saw such a large RC plane, the video was very exciting.