Another exciting week for Canberra UAV and our preparations for the 2020 UAV Challenge. We conducted three more tests of a QuadCopter launching off the back of a fixed wing aircraft, the Hobbyking Bixler 2. We are running this particular Bixler 2 on 4S batteries rather than the normal 3S because it needs the extra ‘oomph to carry a QuadCopter that weighs as much as the Bixler itself! Last week we had noticed that the ‘copter spin up and launch was quite slow compared to the requirement for mid-air launching. Peter has been working on a ‘Punch’ launch mode for auto take-off to solve this problem; essentially a short burst of full throttle with stabilisation to seperate the ‘copter quickly and cleanly from the support aircraft. This ‘punch’ mode seems to work well, but on our limited number of tests we have seen that it is still difficult to clear the Bixler’s pusher prop cleanly. The video graphically shows what can happen when you don’t!
Test 2 is a particular highlight; it seems like Peter has also coded ‘victory roll after take off’ into the ‘punch’ code!
Next week we are moving up to another work horse of the Canberra UAV fleet as the support aircraft; the Boomerang 60. This will also involve a new version of Peter’s successful 3D printed launch rail and some refinement of the ‘punch’ take-off.
We have now proved that air-launch is technically possible and our hardy HolyBro PixHawk 4 QAV 250 QuadCopter has survived every attempt, but we need to make it worthy of a UAV Challenge attempt. During the Challenge the Quad will also be carrying a camera, a microphone and some significant communications gear, so the Quad’s thrust to weight ratio won’t be as healthy as in these tests; this makes it even more important to make the launch stable, predictable and reliable.