Hull Mountain Flights

3-D flight data at Hull Mountain

Northern California

July 6 Flight Top view (north == up) and: July 6 Flight Side view (north == right)

You'll see 3-D flight data collected via GPS during a 1.5 hour flight at Hull Mtn. in Northern California on July 6th, and displayed with AutoCAD.

I've broken up the flight according to how fast I was climbing or sinking, and applied the following color code (as best seen in the July 6 Flight Side view ):

Yellow Climbing "really fast"

Magenta Climbing "fast"

Green Climbing "ok"

Lt. Blue Climbing "barely"

Violet Zero-sink

Red Various rates of sink :-(

In the July 6 Flight Side view , I enter the picture at the lower right, then slowly flush down to the lower left, catching a little burp along the way.

Finally I catch a medium-strength thermal (shown in green), then a bit stronger one (shown in magenta), and fly off into zero-sink to the north (right). Then I fall out of that and return to the center of the screen, where I catch a strong thermal (shown in yellow).

I eventually fall out of that and flush, exitting the picture at the lower left again. Just at the left edge of the picture, you can see I caught another strong one (shown in yellow) on my way to the LZ (out of the picture, off the left edge).

In the July 6 Flight Top view , you can see I've overlaid a top view of the flight data and various GPS waypoints over topo info ftp'd from USGS. Timberline launch is in the upper left, and the LZ is off the bottom of the screen.

If you've collected any GPS data (either 2-D or 3-D) and would like to have something similar made up for your flight, you're welcome to e-mail it to me and I'll overlay it on top of the USGS topo info for that area and send you the results. Due to disk space limitations when downloading topo data, no flights ~25 miles please.

Finally, since the GPS does not itself record altitude, I used the logging function of my Amateur Radio TNC (radio modem) to record the $GPGGA strings (which include altitude) output by the GPS, and various public-domain software packages to get everything into AutoCAD. The Garmin 45 FAQ (available in "Garmin FAQ" under is a great source of information in this area.

=Cliff Olling
Hang III
Garmin GPS 45

cAVe Back to the HG Hull Mtn Page Updated July 18, 1996 Hull Mountain Flights e-mail Cliff

Launch at Hull Mountain Northern California USAMore Hull Mountain California Hang Gliding pictures