Flight Test Log 24
This is one of our best GPS waypoint tracking tests yet. Plus we test a new
elevon mixer that seems to have fixed glitches in the elevon controls.
We had three main objectives:
1. To test a triangular waypoint pattern that was smaller
than the previous 200 m square pattern. The triangle
edges averaged 176 m long.
2. To test a new electronic elevon mixer.
3. To test repairs from the previous crash of 18 August.
Two flights were done. On the first flight, we neglected to verify before
takeoff that the GPS was operating. During flight in autonomous mode, the
airplane was stable but was not tracking waypoints. After landing we noticed
the GPS was not getting position fixes.
After waiting for the GPS to start working, we launched the second flight.
This time the airplane was able to track waypoints. In autonomous mode, the
airplane flew several cycles around the triangle. A total of 10 cycles was
stored in the autopilot memory. Tracking accuracy needs work -- there was
on occasion some overshoot and undershoot at waypoints. The plan is to
adjust the aileron gain to see if that improves the accuracy.
We did not notice any sudden, rapid turns as had appeared in previous
autonomous flights. It's possible this is due to the new elevon mixer,
which was a VeeTail OMNI, and is said to be tolerant of unsynchronized
pulses, a known characteristic of the autopilot. Dave Coombs, the designer
of the mixer, has offered to help us out, and was our test pilot for the
day (see below). Dave did an first-rate job flying.
Date: 2006/09/08 (Fri)
Wind: Light breeze
Scale: 55 %
Location: PCC West Campus
Elevation: 730 m (2400 ft)
Last updated 2006/10/22 FLM