If I convert my tricycle gear trainer (RCM trainer) into a taildragger, can I leave the CG where it is? If this is a messy operation can anyone recommend a good taildragger trainer (or "second plane")?

Yes.. the c.g. must remain where it is... regardless of the landing gear or lack thereof.

While the airplane is flying, it doesn't know whether it's a tricycle or taildragger. I always convert my planes to tail dragger. After 13 years of model flying, I flew my first model tricycle gear plane just this year

It's not a messy operation at all. Basically it consists of moving the main gear forward, and adding a tail wheel. On my Telemaster 40, all I had to do was reverse the main landing gear. This moved the main wheels forward, and made it rest on its tail.

Most likely all you're going to be looking at is choosing a spot just below the leading edge of the wing and reinforcing it with some plywood to take the landing stresses. Also, be sure to put in a little bit of reinforcement at the tail where the tailwheel mounts. This area takes a surprising amount of abuse, especially if you're operating from grass, and I've found that it's much easier to reinforce it originally than to rebuild it after the tailwheel gets ripped out



Tom

People often ask me where the main landing gear should be located when converting a trike gear model to taildragger layout. I have found that a good, simple rule of thumb is to locate the gear such that the model's tail can be raised 30 degrees from horizontal before it tries to nose over, if you fly off a grass strip. This method takes the height of the center of gravity into consideration, not just its fore and aft location. A high wing model, with higher center of gravity, thus needs its wheels located further ahead of the CG than those of a low wing model. If you normally fly from a paved strip, 20 degrees will do the job, and make the model less prone to ground loop. Landing gear location on a taildragger is always a compromise - further forward makes the model resist nosing over, but promotes ground looping. Further back reduces ground looping tendency, but increases the tendency to nose over.

You can expect to re-trim nose down slightly on your first flight after conversion. The nosewheel drag not only slows the ac down, it introduces a small down-pitch moment that you will have trimmed out. Removing the offending nose wheel will require re-trimming to account for the missing down-pitch moment. You may also find that the model spins more easily & rapidly.