How to modify JSBsim initial altitude

I’m trying to use a JSBsim sitl in linux to code for a pure glider I’m working on. To test it I’d like it to start out at altitude. I’ve tried modifying the altitude in the locations.txt file, but that seems to only affect what arduplane reports, not jsbsim. I’ve tried modifying the SIM_JSBSim.cpp to change reset.xml, but as far as I can tell that modifies the ground altitude as well, as the plane doesn’t start falling right away. I’ve also done the same to modify jsbsim_start_0.xml with an event that puts it up to altitude after 5 seconds, but that doesn’t seem to work either.

Any advice would be greatly appreciated. I’m running ubuntu 16.04 in virtualbox

There is a file called “reset.xml” that controls where the aircraft starts. Try changing the value in “altitude” to start the vehicle higher up.