Homebuilt Coaxial Helicopter (RELOADED)

[thjakits]

So - what's the status on the Coax-helicopters here?

 

[quadrirotor]

what do you mean by "status"?

 

[thjakits]

There was a LOT of discussion going on here - and then it suddenly stopped - is there still a discussion or are we just the jokers here?

 

[quadrirotor]

you can contribute! Go on!

 

[thjakits]

Well - I guess it went the way I think it goes - Coaxial is pretty much a dead end for homebuilts....

 

[gwellbeing]

DIY coaxial homemade helicopter project from China

 

[hillberg]

yaw will suffer control reversal in autorotation - other then that it look good

Yaw drag flaps on the tips will do nicely (QH 50 style)

 

[okikuma]

Yes, drag flaps would work nicely IF there's a differential. I suspect that is not in this case because of the chosen method of yaw control. Searching the net, I see most amateur coax designer/builders use this method for equalized counter-rotation.

I can't get over how small the diameter is for both rotors.

Wayne

 

[hillberg]

Yaw flaps will always work. the gearing of a coaxel is not a limiting design feature nor a dynamic or static mas, if you put a fixed set of flaps above and a movable set on the lower blades.

what you show is powered lift with very high disk loading and two rotors way way too close to each other......

 

[okikuma]

Yes, but I was just using this video to quickly show the simple method of creating counter-rotation with a single power source.

Wayne

 

[Jake2465]

This thread is so many pages long that I am having a hard time understanding its overall purpose. Was it to see about getting a coaxial helicopter built?

 

[hillberg]

Cicaré coaxial.

Cicaré coaxial.

Who knows what became those coaxial (Dennis Fetters, may be!?)???
And what are the intentions of Cicare about them???

http://www.cicare.com.ar/index.htm

THOSE WERE TEST SUBJECTS ONLY NO PRODUCTION
Cicare had his designs taken, He's a great designer.
As for the coaxal stuff they mostlyall use standard collective & cyclic controls - Yaw is reversed unless a special null cam is used or tip break servos.
Fixed pitch with mast tilting in the cheaper 'kits' are falling bowling balls with a seat when the engine stops.
All a coax does is add to the costs of extra main rotor blades - controls & headaches - The standard single main & tail systems do better.
I'll take a tandem Chinook over a Kamov coax any day. and a standard Hughes twice on the Weekend.