Dave your obvious hatred for the tail rotor makes me believe that you have
been injured by one at one time or another. As the editor of Experimental
Helo magazine, I get exposed to alternative methods such as you suggest. No
one has demonstrated that they can be economically produced. The addition
of another complete rotor with the accompanying transmission and control
systems add both construction, maintenance costs. The primary savings
available would be in the fuel saved over the tail rotor machine. Would it
be enough? Simple issues such as tracking and balancing blades gets more
complex with the co-axial and intermeshed rotor systems. I would expect that
both of these modes of propulsion would have more modes of vibrations
excitation that would have to be dealt with. I'm having enough trouble
getting 2/rev vibrations under control with a simple two bladed, tail rotor
machine. I can't imagine the difficulties that I would encounter with the
machine that you describe. Have you built and de-bugged your design yet?
Concepts are one thing, operational ships are another. History has said
that all of the major helicopter mfrs. have visited the idea of getting rid
of the tail rotor and gave it up for a myriad of reasons. While technology
has relieved some of those reasons, the physics remain. With all that said
there is one co-axial helicopter that has been test flown that is being
prepped for the homebuilt market: The Ezycopter.
I know of no one flying the intermeshing rotors in a ship that competes
price wise with an equivalent performing tail rotor ship. It just doesn't
seem possible to make a ship with the additional main rotor system and
transmission system and control system that can compete with the standard
tail rotor ship. If I'm proved wrong, a bottle of single malt scotch
whiskey is yours.

--
Stuart Fields
Experimental Helo magazine
P. O. Box 1585
Inyokern, CA 93527
(760) 377-4478
(760) 408-9747 general and layout cell
(760) 608-1299 technical and advertising cell

www.vkss.com
www.experimentalhelo.com


"Dave Jackson" wrote in message
news:XNO0e.778773$8l.282021@pd7tw1no...
Quote from ~ Flight International, Feb 8-14, 2005

"Sikorsky has decided not to bid for the US Army's Armed Reconnaissance
Helicopter and the Light Utility Helicopter programmes and is instead
looking further ahead. "With the business growing, we have the luxury to
look at what is the next big thing we do that is not 'me too'" says Pino
[senior vice-president marketing and commercial programs]. "By the end of
the year we will be better able to tell what the next breakthrough might
be.""

___________________

Dear Sikorsky,

A long sixty years after the inception of the helicopter, you appear to be
acknowledging the need for a second-generation craft. Perhaps, you will
take this opportunity to finally put rotorcraft research and development
back on the correct track; the track where it was, before being pushed off
to the side by the tail rotor.

The German Side-by-side Focke Fw 61 and the Intermeshing Flettner Fl 282
were the world's first viable rotorcraft. Both of these craft had latterly
displaced twin main-rotor configurations. Unfortunately, meaningful
pursuit
of the lateral configured helicopters was never done in North America.

I humbly suggest that the preeminent second-generation large rotorcraft
will
have an Interleaved configuration [http://www.unicopter.com/1121.html ],
with;
~ extremely rigid rotors,
~ active blade twist, with reverse velocity utilization,
~ low tip speed, plus large chord,
~ pusher propellers or fans,
~ no wings (no compound design).

This configuration appears to offer a number of significant advantages and
few disadvantages, when compared to the contending tilt rotor
configuration.


Yours provocatively;

Dave Jackson