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Archive for March, 2010
Posted by SSM | Mar 28, 2010 @ 05:54 AM | 6,113 Views
Is this crazy??

Is there any reason why the principles used here cannot be adapted to make a Quadcopter? Four motors, four gyros (plus one yaw gyro). Elevator gets mixed to vary the front & back motor speed; aileron into to the left & right motor speeds.

Is because there's simply not enough mixing in most radios (and we only get to do the tricopter because we have radios with CCPM mixing, which makes it possible)?

.......

I have just bought a Futaba 10C transmitter. It offers 8 types of CCPM swash mixing - and two of them use four servos at 90 to each other: H-4 and H4X.

With H-4 mixing the four servos are front/rear and side/side, all at 90. With H4X there are four servos on the "diagonals" - that is, at 45, 135, 225 and 315.

I think that these CCPM mixes just might be suitable to make a Quad.

I'm even hoping that with the H-4 mix (four 90 servos) it may be possible to get away with just two ESC gyros - one for elevator, mixed into both the front and rear ESCs, and one for aileron mixed into the side ESCs.

I think I'd use pusher props on two of the motors, running CCW.

Unless there's some fancy way of speeding up the two CW motors and slowing down the two CCW motors (all controlled by a yaw gyro) to produce a net yaw effect, I think I still need a tilting motor and gyro for yaw control.

I feel a HK order coming on. But am I dreaming here? Is anyone willing to tell me this is totally out of the question before I buy?...Continue Reading
Posted by SSM | Mar 20, 2010 @ 09:39 PM | 4,141 Views
The tricopter works great! It's a much better ship than I am a copter pilot. After a lifetime of flying fixed wing, there are a whole lot of new skills to learn, and a whole lot of habits to unlearn, to be able to fly these things competently.

But at least it flies and I've got a basic understanding of the flying characteristics. Here's the video taken from a key ring cam on my cap;

Copter Maiden - Key Ring Camera.AVI (1 min 12 sec)

Posted by SSM | Mar 10, 2010 @ 07:15 PM | 3,947 Views
... and got it back two days later - finding it in a dam about 2 kilometres away!

Here's the record and video of it.

Lost in the Water.avi (2 min 44 sec)


By the way, on this flight I was using the RV 1000mW video Tx that I said I might try. So I was using a Tx that was probably five times more power-hungry than the 200mW Tx I used in the earlier flights. Also, because this Tx is 12v, I used a 12v camera, which probably succked more juice. On top of that, because I was out in the bush, I climbed the plane much harder and higher. No wonder I ran the battery flat in 14 minutes instead of getting two 17 min flights like before. Trust you're not as dumb as I am!
Posted by SSM | Mar 10, 2010 @ 07:11 PM | 3,879 Views
My HK order(s!) have arrived so I've got the parts now. Have started putting them together and programming the 9CHP. Did a little road test of the gyros and they seems to arm and work correctly. The big problem will be getting all the settings right (eg, correct amount of gain on gyros, correct ATV for aileron elev and yaw, pitch curve correct, and the one I don't fully understand, the CCPM setttings on the Tx). The 3 Mystery "401" clone gyros need to be mounted up on their sides, so ignore their orientation in the picture. For testing, I'm using a Corona RP8D1 receiver - but I'm wondering whether their resolution will be too coarse for fine control, especially of the motor ESCs (I have asked about this on the "Build a Tricopter" thread).