RE: Nitro models pusher Bobcat?
I highly recommend flying the Bobcat and fine tuning the set up before anyone considers moving the fuel tank. I am finding that the "real" nuetral CG is closer 11" aft of where the leading edge meets the fuselage.
There have been many posts talking about the need to increase elevator throw, I now believe this is due to forward CG. I moved my CG back from 10.3 to close to 11" by removing .75 oz of lead from the nose. The elevator authority is much better and the plane is still slightly nose heavy based on analysis in flight.
The more I fly the bobcat the more I am impressed. I suspect this is due to the design of the airframe which I think we must credit to Bob Violett for. This plane has a very wide envelope and flys very well. With that said when the model was "converted" into the NitroModels Bobcat some of the background was obviously missing. At the center of this is the CG issue.
I was very fortunate in that many people had already flown the Bobcat when I did my review and had found the CG to be wrong. There were many other issues pointed out by early builder/flyers that made my project easy. I remember several posts scattered through different threads indicated that several CG calculators indicated 11" inches or slightly more to be the correct CG.
I can say with certainty that especially with heavier engines, the pilot needs to run out of elevator at the same time he/she runs out of altitude. If you do this the stock landing gear will not bend. If this is not somthing you can do or you don't have a very smooth landing strip I would simply replace the stock gear wire from the beginning.
Angus and others are sure making me want to try retracts, this plane is fast dirty, I can only imagine how much a cleaner aerodynamic footprint would help.