This small coaxial helicopter looks like a bunch of fun. Sorry if you have seen this before.....
http://www.youtube.com/watch?v=Z83t1iejpc8

I have never flown one of those... however I have read they are not very good at an auto-rotation... should the engine fail.

Hmmm...

That is the first one I've seen that has flown in anything other than a hover.
I like it!

ASK helicopters rebuilt that one it's a GyroDyne RON 1 ,Gyrodyne went out of business and now does industrial building lrases in Flowerfield NY.
That's just a has been company trying to keep in the red,

That Gyrodyne helicopter is nothing new 1950s tech , Navy DASH program & Snoopy opps in Viet nam. Isreal had the last batch in the 1980s.

Drone spy helicopter. ASK also had a QH 50 D maned helicopter with a Rolls Royce 250 c 20.

Theory of flight question:

Seems there is no need for torque control on the tail, so is there really a need for the tail boom at all?

I can understand the horiz stab effect on forward flight, however it appears this craft does quit well flying backwards and sideways.

THX for any thoughts posted!

The QH 50 only had tail vertical stabs for forward flight, the rotor tip drag brakes were for yaw control & were exlent no control reversals and autos were great,
The QH 50 could carry 2 torpedos or depth bombs, the Snoopy was fitted with machine guns.
here's what an Enstrom & Gyrodyn look like mixed together,

That is cool, I like coax heli's!

So...Coax's cannot autorotate?

Here is where I heard that:

Saw a video of Benson Days in the mid 1990's a while back, there was a coaxial there, homebuilt. Guy had 2 (yes two) engines... when asked, he said his coaxial would not auto, so he had a spare engine. This prompted a discussion between the folks I was around, they mostly agreed doing an auto was not a strong suit of the coaxial design.

Now I am sure some of them do... however as I understand some do not.

I suspect someone who knows more than I do, will come along and clear this up... I am interested to learn.

It's not the coax design but rather the fix pitch or variable pitch is the determining factor. Fix pitched rotors can NOT autorotate sufficiently. Of course being able to flatten the blades in an event of an engine out allows you to build up the speed and the kinetic energy in the rotor blades to have a successful flare and if necessary dampen the touchdown with a pull on the collective. It is not the coaxial design itself that can't do it. It is however very complex to build a coax with variable pitch!!!! And that's why experimentals build them fix pitched.
This heli the Diora has autorotation capability

THX Gab, That makes sense.

Appreciate you taking the time to 'splain...

No problem at all John. Another little known fact on coaxial autos that due to the smaller disc size it is a bit harder to steer the damn thing as it has a lot steeper glide angle but it does have more reserve energy in the blades. So if you mess up you can check a collective and still have more to spare for re-flaring ... not that that's ever happened.

Here is a little example starting around 9:25 autorotation of the Kamov 26

WHOAH... that is a beast!

Couple of observations:
*Dual engines, are they small radials? They seemed to belch like a radial starting...
*Not knowing much about capabilities... it does appear the coaxials seem to have a handling advantage over conventional single rotor/torque tail rotor designs... (?)
*That coaxial seems to have considerable vertical ability... then again it appears to be designed as a heavy lift aircraft.
*And I suspect that would be a kick to fly...

THX for the video... Do you have a link to some tech data on the airframe? Would be interested in stuff like the engines, rotor head(s), etc.

Yes they have two 325 HP radials and that is pretty much the weakest point of the KA-26. Those engines suck!!! It is running 95% max at all times. I can't think of another helicopter that would run it's engines at the 95% max load mode! But.....it's Russian made so there is nothing surprising about that little nuance The usage for the coaxials is usually heavy lifting 900 KG about 2000 lbs. Crop dusting and crane comes to mind. Very stable machines though. 2x 13 meter rotors about 42-43 feet. When it's empty you can't kill the damn thing. There is another advantage of using coaxial rotors for crop dusting because the rotor creates an airflow which allows pesticides to settle underneath, rather than on top of, the leaves, this means a much more effective distribution of pesticides, as most pests and parasites do not live on the top side of foliage.

Yes, understand the part about getting the pesticides UNDER the leaves...

And running those radials at 95%... yeah, that does sound like a Russian thing...
Probably runs great when it runs... which again sounds like a Russian thing...

THX for the information... need to get busy on sorting some paper, which sadly is not aviation related... Oh, that messy thing called work...

Have a GREAT one, and THX for the information.

John

You are more than welcome. They are fun to fly ....but again....I am very much set on anything with rotor blades