> Steve, Are you going to design and build
> your own helicopter rotor head?
>
> What do you think of this one?
>
> Paul Lamar ...No rotor no motor.

Gee I don't see why helicopter maintenance is so pricey  :)

John

Here is almost a complete articulated counter rotating rotor head.
I can see why counter rotating rotor head helicopters are so rare. I still
haven't figured out how to move the forward swash plate yet. I am thinking
Blue Tooth radio controlled :) Four high speed, computer radio controlled,
angular electric servos, one on each blade, would do the trick.
It would vastly simplify this and make fly by radio control a real reality.
It could also be done with a infra red optical link.

Another possibility is control the swash plates with three servos each.
The servos would not have to be as fast.

Perhaps the control rods can go into the inner shaft for the front
rotor. About the only company in the world that could build this is Kamov.

It is also still laking the lagging and flapping hinges.

I am not dumb enough to try to build one of these :)

Paul Lamar

I think I read that the control input to the rotor has to lead by about
90 degrees? The top and bottom rotor then have to lead from
opposite directions.
-Jeff Martin

All,
The biggest drivers of the cost of helicopters are lawyers and the
government.  One of the simplest, toughest, and most maintainable rotorheads
is the Hiller U-12 with the servo paddles.  This thing can be maintained in
the middle of nowhere.  With modern materials, this thing would be
bulletproof.  You can see model helicopters flying with these things every
day because it works and it's very cost effective.  Certified helicopters
must be maintained by an A&P and most helicopters are not designed to be
maintained by owner/operators and they have timed out components that must
be replaced on an FAA approved schedule.  For example the Bell Jet Ranger
has these dog-bone looking tension straps in the hub that must be replaced
at (I think) 800 hours and they cost around $1200 each (there are two) and
this is NOT an afternoon job.

By the way, the control inputs to the rotor lead the rotor by 90 degrees
because what you are doing is precessing a gyroscope.  The reality of what
you're doing when you make a control input is that you are tilting the rotor
disc and the fuselage just follows the disc.

Steve Brazil


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