So I am a new pilot. Bought a P2V from a friend for $200. Thought it was great deal and perfect to get experience before jumping into a better model. After a few weeks of research and reading as much as possible, I flew several times with no issues. Except for rough landings. Suffice it to say I learned how to "hand catch" pretty quickly. Anyways, time for upgrading and tweaking. I'm an engineer type, so I can't help myself. Changed out some beat wiring, 9450 props, new landing gear and an upgraded anti-septic compass. Nothing major, just minor tweaks right? The anti-static compass proved to be the most challenging as the length of the cable was considerably shorter than the original. So the only way for me to mount it and allow the cable to reach the GPS puck was to re-locate the compass to the left front leg. The original was mounted on the right rear. (As viewed with the battery compartment facing me). I honesltly didn't think that it mattered where it was mounted, especially since it would be calibrated after install. Pre flight checks, IMU cal, compass cal, wait for GPS and home lock. After takeoff, I come to about 8 feet altitude to do routine controller checks. I usually do this. Yaw left, then right. Roll and pitch etc... But before I get a chance to do anything the thing just takes off, full throttle straight west into some trees. Good thing I didn't go any higher in altitude, there would not have been any trees to stop the flyaway. Minor damage. Two busted props and some dirt and grass stains. After replacing the props, I tried again. Re-calibrated everything, including the IMU. This time I tethered the Phantom using a nylon line tied to my wrist. Again it veers off and tries to roll to a new location. When the tether ran out it started increasing throttle to escape my restraint! It was actually kind of funny. Like a dog on a leash trying to chase a rabbit or something. Anyway, I decided to go back to the original compass and problem solved. Lesson learned: if it ain't broke, don't fix it. Totally against my tinkering nature. Question is, has anyone experienced this or know if compass relocation can cause such behavior? Or did I get a bad compass?