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I recently saw a very interesting CFD study by NASA recently on drone configurations, where they found that a hybrid version with front rotors below the frame a

I recently saw a very interesting CFD study by NASA recently on drone configurations, where they found that a hybrid version with front rotors below the frame and rear rotors above was significantly faster, since the wakes interact less. Wonder if it's been tried on racing drones? https://www.nas.nasa.gov/publications/articles/feature_hybrid_UAVs_VenturaDiaz.html https://www.nas.nasa.gov/publications/articles/feature_hybri... (The flow simulation and visualization in the above link is so insanely high resolution it's borderline pornographic.)

donkeyd 9y ago
I'm not completely sure whether this is as relevant for racing drones as it is for surveillance/video drones. Racing drones often fly at a 45+ degree angle, so the thrust is angled more backwards than downwards. Also, one of the benefits of the NASA research is longer flights. But racers often don't fly more than 1-2 minutes, after which they swap batteries. A slightly lighter battery could give the benefit of slightly quicker acceleration though and that's pretty important. Lastly, in the pro leagues, they usually fly the same drone, so there's no need to have the fastest drone.
halbritt 9y ago
Racing drones typically fly at extreme tilt angles such that the wake of the front props isn't interacting very much with the wake of the rear props. That said, I have seen that configuration on a frame.
jsjohnst 9y ago
I’ve not seen it on racing drones (likely for the reason mentioned by others), but have seen it in mid-range pre-built ones quite a bit. For example, the DJI Mavic has a similar configuration to what you mentioned. I’ve built or bought well over two dozen drones ranging from palm sized to my beast, an octocopter with a 5’ “wing span” that draws hundreds of amps at 25v at max throttle, but never got into racing. I’m much more into the building and photography aspects. I’m tempted to build my own software from scratch next (there’s great open-sourced platforms, but I like the challenge of doing it myself).

donkeyd 9y ago

I'm not completely sure whether this is as relevant for racing drones as it is for surveillance/video drones. Racing drones often fly at a 45+ degree angle, so the thrust is angled more backwards than downwards. Also, one of the benefits of the NASA research is longer flights. But racers often don't fly more than 1-2 minutes, after which they swap batteries. A slightly lighter battery could give the benefit of slightly quicker acceleration though and that's pretty important. Lastly, in the pro leagues, they usually fly the same drone, so there's no need to have the fastest drone.

halbritt 9y ago

Racing drones typically fly at extreme tilt angles such that the wake of the front props isn't interacting very much with the wake of the rear props. That said, I have seen that configuration on a frame.

jsjohnst 9y ago

I’ve not seen it on racing drones (likely for the reason mentioned by others), but have seen it in mid-range pre-built ones quite a bit. For example, the DJI Mavic has a similar configuration to what you mentioned. I’ve built or bought well over two dozen drones ranging from palm sized to my beast, an octocopter with a 5’ “wing span” that draws hundreds of amps at 25v at max throttle, but never got into racing. I’m much more into the building and photography aspects. I’m tempted to build my own software from scratch next (there’s great open-sourced platforms, but I like the challenge of doing it myself).