Roger,

Yes I believe I did have another post much earlier about my T-33 and you are correct, it did not have the JMP bypass or tailpipe. It had a BVM bypass shroud and a Tamjets double-walled pipe and RAM-1000. This was the setup when we noticed the trim change. I have not used the JMP bypass because I purchased the plane mostly built with BVM turbine T-33 intakes installed and came complete with the shroud.

The BVM intakes are still in the airplane but the rest has been removed. I have ordered a Jetcat P-120 engine to put in it and a Jet-Tech(Gary Mueller) bypass and pipe for the P-120. I previously did not have any insulation in the rear of the fuselage but when the re-installation takes place, I will be using the ceramic insulation material that BVM sells.

It is still a mystery to me why the elevator trim changes up from center so noticeably since an expanding pushrod(carbon fiber) would give down elevator. At the same time, we did not notice any change in the rudder trim. The rudder is actuated via pull-pull cables.

Maybe the guys are right when they say fuselage expansion but I am getting a lot of up elevator trim change . I was hoping that someone would know for sure what the the cause is since I consider myself still on the steep side of the learning curve when it comes to the care and feeding of turbines.