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Kamov folding helicopter?



 
 
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  #11  
Old October 28th 03, 07:29 AM
Al Denelsbeck
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"Trentus" wrote in
:

"Mr.Twistair" wrote in message
...
Joss, this heli is slightly described at http://twistairclub.narod.ru
including photos of it's step-by-step unfolding. It wasn't ever
flown. The main reason why is mostly explained as "no suitable engine
which would fit this design that time". I've heard that it was
designed to be powered by small rotary engine but the engine wasn't
actually built (never run good enough - to be exact).


Pardon me while I drop my guard and flash my ignorance to all and
sundry.

No tail rotor?
I assume the twin sets of rotors turned in opposite directions to
counter the resultant forces that would cause it to spin otherwise.
How would you then turn one? I believe you turn a helicopter by
altering the amount the tail rotor counters the tendency of the craft
to spin? How would you turn a helicopter that has no tail rotor.



Sorry about coming into this so late...

The coaxial rotor helicopters have fully-articulated rotors on both
heads. Yawing is acheived by increasing the pitch on one (and probably
decreasing the pitch on the other simultaneously, so no increase in overall
lift). This produces more drag from one head, less from the other, so the
anti-torque effect is minimized and the aircraft rotates against the
increased pitch rotor.

I, personally, would like to see a closeup of the swash plate and
links assembly, to see how they manage to get past the lower head to
articulate the upper. Everything I've thought of so far leaves out some
aspect of either collective, cyclic, or precession.


- Al.

--
To reply, insert dash in address to separate G and I in the domain
  #12  
Old October 29th 03, 05:44 AM
terra
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Al Denelsbeck wrote:
I, personally, would like to see a closeup of the swash plate and
links assembly, to see how they manage to get past the lower head to
articulate the upper. Everything I've thought of so far leaves out some
aspect of either collective, cyclic, or precession.


This makes it all so clear...
http://www.b-domke.de/AviationImages...head/1363.html

  #13  
Old October 29th 03, 07:45 AM
Al Denelsbeck
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terra wrote in
:

Al Denelsbeck wrote:
I, personally, would like to see a closeup of the swash
plate and
links assembly, to see how they manage to get past the lower head to
articulate the upper. Everything I've thought of so far leaves out
some aspect of either collective, cyclic, or precession.


This makes it all so clear...
http://www.b-domke.de/AviationImages...head/1363.html


Umm, yeah, kinda... ;-)

It's a good detail pic, thanks! Still hashing it out, but looks
roughly like my first suspicions. But something puzzles me, not being
involved in rotor design or maintenance: I was told, a long time back, that
because of precession, the cyclic input for forward flight, for instance.
occurred slightly ahead of the point where pitch was intended to be
greatest. In other words, a little advanced in the rotation from full rear
position on the rotor disk (much like ignition timing on a car, just for
different reasons). Easy enough to do on a standard rotor assembly, but
requires displacement to both sides on a coax. This doesn't seem to show
such a design, unless I'm missing it (entirely possible). Was I misinformed
long ago? Anyone?


- Al.

--
To reply, insert dash in address to separate G and I in the domain
  #14  
Old October 29th 03, 01:19 PM
PW
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"Al Denelsbeck" wrote in message
. 8...
terra wrote in
:

Al Denelsbeck wrote:
I, personally, would like to see a closeup of the swash
plate and
links assembly, to see how they manage to get past the lower head to
articulate the upper. Everything I've thought of so far leaves out
some aspect of either collective, cyclic, or precession.


This makes it all so clear...
http://www.b-domke.de/AviationImages...head/1363.html


Umm, yeah, kinda... ;-)

It's a good detail pic, thanks! Still hashing it out, but looks
roughly like my first suspicions. But something puzzles me, not being
involved in rotor design or maintenance: I was told, a long time back,

that
because of precession, the cyclic input for forward flight, for instance.
occurred slightly ahead of the point where pitch was intended to be
greatest. In other words, a little advanced in the rotation from full rear
position on the rotor disk (much like ignition timing on a car, just for
different reasons). Easy enough to do on a standard rotor assembly, but
requires displacement to both sides on a coax. This doesn't seem to show
such a design, unless I'm missing it (entirely possible). Was I

misinformed
long ago? Anyone?


- Al.

--
To reply, insert dash in address to separate G and I in the domain


Precession and dyssemetry of lift are cancled in coaxials as far as I know.


 




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