"If you're willing to connect a Raspberry Pi to the Telem2 port and read the MAVLink messages using dronekit (this requires a little programming), then you can record the changing pressure vs. time, which will give a pretty accurate descent rate with…"

"Welp, I didn't get any answers here, but I'll report for the benefit of others that MavProxy turned out not to be the solution to my problem but rather the dronekit module, which got me to the point of running a working demo program in about an hour."

"Ted,
We've only flown it once! For me, a relatively new RC pilot, it was a "holding the tiger by its tail" kind of moment, and I was glad to have a more experienced pilot at the controls. As you noted, the aircraft is fast and needs a lot of runway,…"

"Here's a better link focusing more on the bungee launcher: https://www.youtube.com/watch?v=xDwImUzHHkM"

"Great points. Looking forward to seeing your new product when it comes out.

BTW,here's a video I just found of a bungee launcher that seems to do a nice job with the Skywalker X8: https://www.youtube.com/watch?v=PqEESKzy_iQ"

"David,
Thanks for the additional comments and info.  A couple of quick comments/questions for now:

1)  Is this the Skywalker X8 you're talking about?  https://hobbyking.com/en_us/skywalker-x-8-fpv-uav-flying-wing-2120m... I've seen videos of this…"

"I'm not quite sure where the 3G comes from if my target airspeed is, say, 15 m/sec (about 30 knots).  In that case, a 1G acceleration should accomplish that over about 10 meters.   3G over 10 meters would give three times the energy, or 24.3 m/sec…"

"Very helpful information; thank you very much.
I'll add that I had been thinking about a relatively long track so as to greatly reduce the required g-forces.  As a starting point, I believe a 10-meter track (still greatly reduced compared to the…"

"Tim - It's the X8R! "

"Looks like you're not getting anything from the RC receiver.  I had this problem recently too, but intermittently. Fortunately, I had a spare receiver laying around, and when I replaced it, the problem went away.  That led me to conclude that it was…"

"Update:  After many long delays (most related to other projects I'm tied up with), I am getting close to having the Hugin 2.6m flight-ready.  BUT ...
With it now fully assembled, including electronics, and sitting on a table, I'm unsettled by the…"