Flight Test Log 19
First sustained autonomous flights with GPS waypoint tracking combined with
Date: 2006/07/04 (Tue)
Launch 1: 18:33
Launch 2: 18:49
Launch 3: 19:13
Wind: Light breeze
Scale: 55 %
Mass: 962 g (2.12 lbm)
Pilot: Robert Wagoner
Location: PCC West Campus
Elevation: 730 m (2400 ft)
This was our second set of test flights with the new autopilot. A total of
three flights were made.
The first launch ended with a hard landing on takeoff due to lack of airspeed.
The nose was slightly damaged and the lower carbon spar cap was partially
delaminated from the crash.
The second launch was successful. Several times during the flight, when we
switched to autonomous mode, the roll angle diverged. This turned out to be
caused by reversed aileron outputs. We corrected the problem by removing a
jumper on the autopilot.
The third launch resulted in several minutes of autonomous flight, where the
vehicle attempted to fly to a single GPS waypoint. The vehicle appeared to
successfully track the waypoint, and also held constant altitude. When the
vehicle tracks a single waypoint, it either orbits or flies a figure-8
through the waypoint.
For this flight, the longest contiguous autonomous flight was at least 284 s
(4.7 min) out of 353 s (5.9 min) total flight time, as measured by a video
record. The times were actually longer, but our camera ran out of memory at
The previous roll oscillation problem seems to have been cured. Also, there
were no apparent phugoid oscillations, which was a question that was raised at
static judging at the 2005 IARC competition.
This was also a test of a modification to the fuselage hatch, where several
magnetic attach points replaced duct tape for holding down the hatch. The
change worked out OK, and made it much easier to get access to the avionics
Last updated 2006/07/05 FLM