With a brushless motor and a TRex tail rotor mechanism I could assemble a simple variable pitch system. I measured and it generates 700g with the TRex 500 tail rotor blades.
I tried the Trex 250 blades from the main rotor but although they are longer the thrust is smaller, just 400g. This is probably because the motor doesn't have enough torque.
This could be used for a variable pitch quadcopter or with an airplane.
Specs:
Motor: Hextronik DT750
ESC: Plush 25A
Battery: Turnigy 2200mah 25C
Tail rotor: HK-500GT
Wood to support the tail mechanism: 38mm tall
Comments
Ok, so we are getting to the point of getting four helicopters and connecting them together with sticks. Starting to see why some people have claimed this as busted.
Matthew, the main rotor would be better for using larger blades, however it would be more difficult to change the pitch angle (collective) since it has a swashplate. It would need some modification ;)
Can't help feeling that you are better off using main rotor heads instead of tail rotor mechanics since they are designed to take the load. Just a hunch. What do you think?
Thanks for the tips Joly! So may be autorotation with 4 motors and 4 variable pitch mechanisms wouldn't be possible since they may not turn at the same speed
Hhhauhauah i thought it would be as dangerous as a 12" prop rotating, but may be it's sharper?
hands down: one of the most dangerous videos I've ever seen.
Yes a clutch would help but would be very complex to add. I think that may be better to use larger blades and maintatin the motor always attached to the blades ;)
I guess you might also need a clutch on the prop otherwise or will be trying to turn the motor during autorotate.
Matthew, to do the autorotation, first you need to invert the pitch so as you go down the air that passes thru the blades accelerate them. Although you are not creating lift the blades generate drag, like a parachute so you have a controled descent. When you are near the ground, you invert the pitch so that you can create lift from the kinectic energy of the spinning blade ;). The main problem is to know that if 4 rotors like these would generate enough lift because they seem to have low inertia.
The blades are symmetrical, if we use a different one it would perform better in just one direction. During my tests I've put an aluminum board in front of my chest and i wore safety glasses hhehehe
hauhhauhauha, thanks for the tip andrew
Valeu Guto! ;)
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