altimeters onboard reported altitudes of 10,172 and 10,404 feet.
These are very close to and even straddle the 10,326 feet reported
independently by the GPS system. The
ARTS altimeter reported
9,574 feet based on its barometric sensor. This appears to be just a
little bit low. The ARTS altimeter reported 11,002 feet based on its accelerometer data, which as usual for this particular unit, appears to be
a bit too high.
This was the first flight
of Angelfire where the ARTS recording altimeter was wired into the
ejection charges. On all previous flights it was along for the ride
in order to record data but was not responsible for any deployment events. It
was used on this flight and will be used from now on because it allows the
main chute to be deployed at 1,500 feet. The Missile Works
altimeters that are normally used for deployment can only be set to a
maximum altitude of 1000 feet. This has proven to be a bit too low
on previous flights. Sometimes it just barely gives enough room for the main chute
to deploy and inflate. There is not much safety margin.
The ARTS data shows the
peak velocity was 511 mph. This is very good agreement with the GPS
data that gave 535 mph. Maximum acceleration was 5.8 G's. Angelfire
reached apogee in 27 seconds. After that, it descended on the drogue
chute for 93 seconds at 62 mph and then fired the main chute deployment
charge at 1,600 feet. According to the ARTS altimeter it descended
on main at 14 mph for 73 seconds. Total flight time was 3 minutes and 13 seconds.
All of these number are in very good agreement with the values derived
from the GPS readings.