I also believe that there must be a conflict...or perhaps the x52 is glitching....
Ok...to answer Gregg first. I have made sure that no buttons or axis for the x52 are assigned in fsx except for the aileron, elevator and rudder. Also I have made sure that there are no buttons for the x52 that are assigned in fsx. Llikewise the same in fsuipc...and I might add that I have been flying flight sims since my first computer in 1986 and this is the first time that I have ever used fsuipc. I also have a clean, non programmed profile in the x52 programmer...no assignments there as well.
I might add that this "glitch" only happens with the engines running, with the throttle increased. I will do more testing this evening. I think that I will also delete my fsuipc ini file as well. I have considered totally uninstalling fsuipc...something tells me that is the culprit but only a gut feel at this time.
Matteo, it is comforting to know someone out there is successful with the x52 pro and the j41. Are you using fsuipc, or saitek's programmer? Also just for info, on most other turbo props, the condition lever is actually mapped to the mixture control, but in the j41 it is mapped by default to the prop control. What control on the x52 are you using for the condition lever and how do you have it mapped?
ltalley