left turning (counter clockwise) propellers

[krelis]

Hi there,

I'm designing a VTOL that will rotate it's engines horizontally for take-off.

I want two e-motors (50W) to counter rotate to eliminate any torque influences. So, first challenge, 2 identical props, one designed for regular clockwise turning and, one to to run the other way around.

I've been everywhere on the Web, but no luck.

Anyone?

thanks,

Krelis

[Killerush]

Wouldn't that be called a "pusher prop"?

[krelis]

Thanks,

I have seen those, but had not made the connection; I was kind of confused by the Zinger site, who have both clockwise and counterclockwise pushers...

But I now think if I reverse mount a clockwise pusher, and make it turn counterclockwise, I have what I need!.

[Killerush]

Sounds right to me. Good luck and post some pics when you get it done, I'd like to see it!

[krelis]

Sure thang, Rich!

Ordered 2 props today (master airscrew), only waiting for Mr Potensky to ship the 50W outrunners. Can hardly wait...

[krelis]

It's been a while but here's the status of the little project: I'm stuck; First learning: I started this thread with the search for counter rotating props. I found them, but they did not really match the motors. So it appears that 2 props turning in the same direction can be easily offset by a slight difference in tilt. what a surprise..

Anyway, the real problem: Stability! It's just like a heli, and applying a lot fo dihedral makes it slightly self correcting, but also rocking left to right extremely. So if I want to build anything like the real thing (and not a heli) I need help!

Attached a pic of what I have sofar.

[cayuse]

Krelis,

Look at Toddsmodels.com in the "other propellors" sections.
You'll see LH/RH pairs of 10x4.7" props which are fairly well suited to the slower 50W outrunners. Using these, you can avoid twisting the engine booms, which should ultimately reduce your control problems.

As for the engine tilt, are you saying the machine rocks L/R too much?
Are you possibly overcontrolling? Do your speed controls have enough "resolution" to make very slight adjustments to each motor's RPM?
You might try a gyro mixed into your "aileron" function.

I've seen video of a Tri-copter with essentially your setup extended to 3 motors and it flew very well.
http://www.rcgroups.com/forums/showthread.php?t=439091&page=2

Good luck,
Gary

[krelis]

Gary,

thanks for your post; I learned 2 things: I need a gyro and more size!

However: as with a chair there's a big difference between 2 and 3 legs.

What I'm after is
http://www.bellagusta.com/

FYI what I had sofar was 2 props with 1 controller. Inspired as I am now I'll run my proto with separate controllers and see what happens. Don't have a gyro (hate heli's...).

I also found a nice outrunner to match the Master airscrews: RCTechnics.com 282616 Brushless Outrunner 1611KV (282616) = 12.50EUR

To be continued (inna while, I used my motors in a Trimotor fixed wing setup. great torque!)

Cheers,

Kees

[cayuse]

Kees,

Good luck with the Agusta.

A word of advise: Don't let prejudice get in the way of progress!

Too many times, I've doggedly pursued some challenging project, only to be stymied by some initial assumptions or prejudices (ie, no gyros, must fly on an IPS-A, etc.). Once you see past them, you wonder why you ever let them get in your way.

Cheers,

Gary