Ardu(tri)Copter gets converted to Ardu(Y6)Copter

I.S. April 1, 2011 at 7:07pm

as far as I know the different rpm won't produce yaw, but the difference of propulsion, so in fact making up and down motor consuming equal will null the yaw effect.
correct me if I am wrong.
I didn't get why the coax set up works on helis.

Gord Likar March 31, 2011 at 6:09pm

Seems like a good idea. I haven't done the math but wouldn't you need twice the rpm to catchup to the flow from top blade? Yaw problem there.

I.S. March 31, 2011 at 5:49pm

Lets introduce another parameter:

How about putting a higher Kv motor on the bottom?

Gord Likar March 31, 2011 at 5:31pm

Seems to be a cone of silence around Y6 efficiency so awhile ago I decided to do some tests. Tried 12x3.8 on top with each of 12x4.5, 12x6, and 12x8 on the bottom pushing. Made sense to me to try more pitch on the bottom blade since it's screwing into a relative wind from the top blade. Results were disappointing. Each motor alone can produce 1100 grams thrust at 19 amps 3s (11.2v-11.5v). The best result was with 12x8 on the bottom making ~1500 grams total thrust. Typically at full thrust the top motor drew ~19 amps while the pushing motor drew from around 5 amps for the 12x4.5 to 10 amps max for the 12x8. It looked to me that basically the bottom motor is freewheeling at it's KV. The motors are BC2836-11 750KV. Think coaxial setups are good for helicopters because 25% of power goes to the tail. The only efficiency gain for a Y6 might be that the downwash swirl is straightened out. I'm looking forward to your test results, maybe I got it backwards.

Developer

Max Levine March 31, 2011 at 9:14am

I moved to All TOP CCW / BOTTOM CW setup for now, (we will update the ACM code soon).
There is UP/DOWN drift when YAWing, because of the speed difference :) we need do some fine tuning.
But it fly well on default ACM PIDs and 3S lipo (but its a bit lazy) 4S is grate but it need lower P (0.5 or 0.4)
I'm waiting for 12X4.5 props for more testing..

There was a suggestion to use 12X4.5 on TOP, and 10X4.5 BOTTOM, and also run them a different speed, more on that when I'll get the props :) ( my frame have 50CM arms, so 12X4.5 props for all motors, probably the best for that size )

There will be more info after this weekend :)))

Daniel Gru March 31, 2011 at 8:27am

How's the flight testing going? Are you pleased with the result?
And is different speed for top and bottom rotors working?

Regards

Dnaiel

Knut Kallevik March 20, 2011 at 3:47am

I can confirm this is flying like a quad, I have one built, flying with a KK controller.

I'm not into programming, just a newbee on programming, but into mechanical construction.....I like to experiment whith different setups on frames. I have been waiting for a code for my arduinopilot and DIY shield that I can use with my Y6.......I really like the way this Y6 flies, but I would like to have the opportunities Ardupilot do have...especially auto levelling and auto stabilization for filming and photo.

Developer

Max Levine March 20, 2011 at 3:34am

@sid
It flys same as quad, you add power to left motors and it will fly to right ....
Do you have Y6 frame ready to fly ?

sid March 20, 2011 at 12:23am

@sebastian sorry I did not pose the question properly. I meant sideways flight , left and right.

SID

Developer

Max Levine March 19, 2011 at 3:28pm