One of the common challenges comes from the fact that the full-scale airplane has this heavy motor in the front while your rubber model only has a propeller in front and the rubber motor is located along the length of the fuselage back almost to the tail. If possible, building the tail as light as possible saves having to add excessive weight in the nose to balance the airplane and reduces the overall weight. On the Guillow's Super Cub I built the tail by curving the wood while wet to create lightweight tail surfaces, this plane flies very well without any nose weight.
Other challenges come from the lack of dihedral and the smaller tail surfaces when building a model that looks closer to it's full-size counter part. In the links below are short videos of some my previous rubber scale airplanes that did not fly too well at first. With some adjustments the planes all flew better but not perfect. It has been a learning process and I try minimize problems during the building phase based on my previous experiences if possible.
Last winter I constructed the Herr Engineering Aeronca Champ rubber powered airplane. Plans are adequate but not as detailed as with some kits, the wood was good but not excessively light. When completed I thought it looked fairly well for my skill level but I am no master builder.
|Start of the Construction|
For the first flights it became apparent the plane had too much turn to the right, in the field the only way I had to correct was clay on the left wing tip. With a gentle right turn the plane would climb very steep and hang on the propeller resulting in a stall to the ground. Clay was added to the nose until the climb seemed about right, this put the CG as indicated on the plans. As seen in the video clip I took the flight path is rather wobbly yet, I am trying washout in the wing for the next flights.
|IMP Model Flew Perfect With No Adjustments|
Hopefully I can get another video clip when this plane is flying smooth.
Flight Videos of Some of My Other Rubber Models
Guillow's Super Cub
Guillow's Cessna 180 - bad flight
Dumas Curtis Robin - some stalling
Minnow ROG - flies perfect every flight