PRATCHETT soars to 31,000m for Pixhawk test flight

Our Low Orbit Helium Assisted Navigator (LOHAN) project is in good shape following last Saturday's PRATCHETT avionics test flight, named in honour of the late Discworld author Sir Terry.

Our US allies at Edge Research Laboratory launched the PRATCHETT payload (above) - comprising an avionics package as mounted in our Vulture 2 spaceplane - from Colorado Springs East Airport.

It was another textbook mission by Edge, with the payload coming down some 25km from the launch point, having hit a tad over 31,000m at balloon burst. Here's the flight path on Droneshare, as per the Pixhawk data uploaded by Andrew Tridgell, who was on hand to monitor the mission live via our 900MHz radio link:

And here's the payload hitting the ground, just a short walk from the pursuit vehicle:

Suffice it to say, the avionics survived the flight, and the data showed that our batteries and servos are able to handle the cold at altitude. Here's a sample graph, courtesy of Tridge, showing the voltage situation during the mission:

The 900MHz radio didn't behave quite as well, due to some interference which scuppered our planned two-way comms with the Pixhawk.

It's not a major issue, and we're investigating just what caused so much noise. There are full details on the flight, including more photos, and data from the Pixhawk, right here.

As ever, it's a big ta very much to Tridge and Edge for their magnificent work. We now just need FAA approval to launch the Vulture 2 and we're away. Hopefully, that will be granted before the heat death of the universe, but it's fair to say that the FAA moves in mysterious, and inexorably slow, ways.

Views: 918

Comment by Petr Hubacek on June 17, 2015 at 11:23am

hello, I like this activity. Could you please correct the link abowe with more photos? There is missing char ":" in the http that makes link not work :)

Comment by Paul Meier on June 17, 2015 at 2:34pm

GREAT stuff.... I understand that you are using RFD 900u on the air, what about on the ground ?

And why are you not using the normal RFD 900 on the air ?

Cheers, Paul

Comment by Ryan Biddle on June 17, 2015 at 4:05pm

very cool project. Its got my mind racing with ideas.

ever considered the payload be a fixedwing drone?

launch up to 31k then see how far you can get lateraly? 


*new to the forum. hope to learn a lot here*


Comment by Joe Breznai on June 17, 2015 at 4:33pm

Ryan, check out the link to the LOHAN site.

Comment by Lester Haines on June 17, 2015 at 11:12pm

@Paul The RFD 900 is too big to fit in the aircraft. Here's the inside of the fuselage before we fitted the radio:

Comment by Andrew Tridgell on June 18, 2015 at 12:48am

@Lester, when I told Rob and Randy about this project they raised the idea of also strapping a small quadcopter (maybe a 250 size?) to the payload, then releasing both plane and copter at the same time. It would then be a "plane vs copter" race back to the spaceport

I suspect it won't work as the wind drift will mean a copter can't make it, but thought I'd mention it in case you are feeling particularly crazy. Worlds highest quadcopter flight would be nice!

Comment by Lester Haines on June 18, 2015 at 3:17am

@Andrew - A mad idea, but strangely attractive. Doable, but we'd need a completely different launch set-up/release mechanism for such a flight - the latter being the big challenge. I'd go for 5,000m or so for starters, just to give the props a chance of catching some air. Hmmm, got me thinking now...

Comment by Linus on June 19, 2015 at 12:56am

lets just add such rocket motor to a autonomous fpv race quad (solo?) and chase the thing :) just kidding


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