Angelfire carried its usual assortment of electronics on this flight.  The drogue and main parachutes were deployed by two Missile Works RRC2 altimeters and an ARTS recording altimeter.  The ARTS altimeter recorded the entire flight profile using both a barometric sensor and an accelerometer.  Angelfire also carried my homebrew GPS downlink system in the nosecone and was transmitting information to the ground during the flight. There was also a Walston radio transmitter at 216 MHz in the nosecone for backup "just in case".  However, it was not needed for this flight.  We were able to enter the last GPS coordinates transmitted to ground into a hand held GPS unit and then walk directly to it.  Angelfire landed about a half mile north of the lake bed in among the scrub brush.

Angelfire landing site.

This was the eighth flight of Angelfire. 

The first flight of Angelfire was at LDRS 24 in Canada in 2005.  Click here to see photos of that flight.

You can view this trajectory in simulated 3D by downloading the data file at the link below and loading it into Google Earth.  You can then use all the standard  pan, tilt and zoom controls in Google Earth to see it from any angle.  Just right-click on the link below, save the file to a convenient place and then open the file from inside the Google Earth program.  (Google Earth is a FREE program available here.)

The charts above show the altitude and velocity data reported by the GPS system.  Each point in the plot represents one GPS reading.  This GPS unit updates at five times per second. (Readings are spaced apart by 200ms.)  The peak altitude was 10,326 feet above the ground.  The peak velocity was 535 mph.  The descent rate on drogue chute was about 67 mph and then 16 mph on the main chute.

The velocity data plotted above is just the "up" component of velocity.  The GPS also reports the "north" and the "east" components of velocity to give a true 3D velocity vector.   To see plots of all of the GPS data click on the link below. 

Click here to view Angelfire GPS data plots in PDF format

Flight Trajectory Video

This is a short 35 second video that shows a 360 degree "fly around" survey of the Angelfire flight trajectory.

View High Resolution MPEG2 version     (12 MB)

View QuickTime version      (7 MB)

View Low Res  Windows Media Player version   (3 MB)

Six pages of analysis of the data from the ARTS recording altimeter are presented below.  You can click on each page individually to see an image of it, or you can get all six pages at once in a higher resolution PDF document at the link below.

The two MissileWorks 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.