Flight Test Log 25
This was a successful test of a new GPS data recorder. Objectives of test:
1. To test a new in-flight GPS data recorder.
2. To test tracking of a small 110 m square waypoint
Dave Coombs made the new data recorder from a GPS receiver and small micro-
controller. The GPS receiver was a Leadtek GPS 9805 III, and the
microcontroller was a Texas Instruments MSP430x13x mixed signal micro-
controller. GPS data was stored in EEPROM for downloading after flight.
Total flight time was 42 s. At 28 s into the flight, before we were able to
switch to autonomous mode, the motor lost power. Except for throttle, flight
control was unaffected. The vehicle was not able to make it back to the
landing site, and it crashed, with minor damage to the wing and motor mount.
After the flight we were able to download data from the GPS recorder.
The motor power loss can be heard on video that was recorded on a
It was not clear what caused the power loss. Several days after the flight,
a discharge test of the battery showed the battery still had about 73 % of
its rated capacity, so the power loss was probably not due to a low battery.
Note that flight control was maintained after the power loss, so there was
not a total loss of power. A single battery powers all systems on the
vehicle except for the flight termination system.
Shortly after the battery test we noticed the motor case was partially
separated (see below). We're investigating whether this explains the power
loss. It's not clear whether the case separation occurred before the crash
or was caused by the crash.
Separated motor case
Motor case comparison, before-and-after
Date: 2006/09/22 (Fri)
Scale: 55 %
Location: PCC West Campus
Elevation: 730 m (2400 ft)
Last updated 2006/10/22 FLM