Intro: Flight: Build Thread: http://forums.openpilot.org/topic/9490-variable-pitch-quad-copter-using-single-motor/
Yeah! That's awesome! I always knew this would work.... No reason why not, I did a lot, I mean a lot, of research on this and all the guys in the forums said it would never work, they even said that there have been attempts at using tail rotors like this that failed. Maybe that was before good controllers? At any rate, good find! This is what will be required for building a gasser multirotor, it's the only way you could........
I always thought a variable pitch setup would be cool and makes sense, but I didn't think about a single motor. I wonder if this is more or less efficient as our normal quads with four motors and ESCs?
One big motor would be more efficient than 4 little ones, and the constant rpm vs a million adjustments would help too. But the big thing is that on a big variable pitch quad, like something that uses 4 450 heli main rotor setups is that you could auto rotate in the event of a loss of power, just like a heli. You could glide the thing back instead of have it drop like a stone. You really only have one motor on a quad as it is, lose any ONE of the four and it's crash time, no chance to even try to control it.
I'd like to see a quad like this one swinging four sets of 450 size (325mm-350mm) main blades. That's going to be a decent sized quad. I wonder what lifting capability you could get with that setup.
I found this variable pitch quadrotor video. It's not single motor but very cool and they demonstrate inverted flight.
That's cool, this is truly the next step, all multi rotors will be like this in the future, I am sure of it and this video shows exactly why. Look at how that thing can flip. The shafts are hollow and pitch is applied just like a UH1 tail rotor 8) Instead of 450 mains, you could just use giant tail rotor setups like the first video, but with trex 700 tail booms, or find something even larger.
What I also think is great is the stopping and starting. You see in the side by side that throttle up and then stopping is very quick on the variable pitch version. I presume this type of quad can be setup more like a helicopter whereby the throttle RPM would remain constant and one only varies the pitch of the blades.
Just found this, this guy did a lot of work to make this happen. http://www.virtualrobotix.com/profiles/blogs/hg3-the-era-of-quad-variable
Now that is awesome. Full 450 size main blades and variable pitch. The only change I would make would be to use torque tube drives instead of belts. Maybe I would also look into making it like the small one we saw a while ago with hollow motor shafts and the pitch mechanisms running through them. I know this would mean four motors instead of one, but I like the idea of less mechanical moving parts.
This guy built this like 10 years ago, no electronics for stabilization, just the seat of your pants flying...... http://www.youtube.com/watch?v=rcubbloN4HU
The first quad of this topic has crashed, you can hear the drive gear give out just before it goes down..... http://www.youtube.com/watch?v=RCuAzLeZW_0
Can you imagine flying that without stabilization? That had to be scary. In the second video he says one of the torque tube gears stripped. This is why I think running four motors, though less efficient, is better since you eliminate a lot of mechanics and moving parts. You lathe/CNC guys should look into hollowing out some electric motor shafts.
