Contra-Rotating Coaxial Rotor Helicopters

(WaltBJ) wrote in message . com...
For one, I can see that the cyclic pitch control system is not a
simple setup. In essence you need two sets of them, one for each
rotor, and with modern helicopters you need a double set of hydraulic
actuators, and some way to get the controls to the top rotor
actuators. So - $$$$$.
Walt BJ

Personaly, from an aestheic point of view, I prefer intermeshing
rotors. You avoid the complexities of a tail rotor and a coazial
linkage in a coaxial rotor.

They used to be quite common: Pieseki I think, Kaman and I think the
Germans had a little intermeshing Focker anti submarine unit in
service in WW2 circa 1943/44. What happened?

In article ,
(The Enlightenment) writes:
(WaltBJ) wrote in message . com...
For one, I can see that the cyclic pitch control system is not a
simple setup. In essence you need two sets of them, one for each
rotor, and with modern helicopters you need a double set of hydraulic
actuators, and some way to get the controls to the top rotor
actuators. So - $$$$$.
Walt BJ

Personaly, from an aestheic point of view, I prefer intermeshing
rotors. You avoid the complexities of a tail rotor and a coazial
linkage in a coaxial rotor.

They used to be quite common: Pieseki I think, Kaman and I think the
Germans had a little intermeshing Focker anti submarine unit in
service in WW2 circa 1943/44. What happened?

Flettner in Germany, Kellet adn Kaman in the U.S. Flettner lost the
War, The Kellets had problems with the blades hitting each other, but
a lot of Kamen K-225s (Navy HTK trainers) and K-600s Navy HUK-1s,
Marine HOK-1s, and AIr FOrce H-43s) wer made. With theeir low disk
loading, they could lift like anything, setting a bunch of altitude
records, and they were, from what I hear, almost too easy to fly. But
the bik killer was drag. While they could climb lije anything,
forward fligh has been described to me as "Pushing your Grandmother's
Turkey Platter sideways through a hurricane". They weren't fast, but
they sure were slow.

Kaman has had a bit of a resurgence with the K-Max, a dedicated crane
based on the K-600, and a few K-600s are used in the Pacific
Northwerst for logging. Just don't try to make one go faster than 100
mph.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

The Enlightenment wrote:

(WaltBJ) wrote in message . com...

For one, I can see that the cyclic pitch control system is not a
simple setup. In essence you need two sets of them, one for each
rotor, and with modern helicopters you need a double set of hydraulic
actuators, and some way to get the controls to the top rotor
actuators. So - $$$$$.
Walt BJ


Personaly, from an aestheic point of view, I prefer intermeshing
rotors. You avoid the complexities of a tail rotor and a coazial
linkage in a coaxial rotor.

They used to be quite common: Pieseki I think, Kaman and I think the
Germans had a little intermeshing Focker anti submarine unit in
service in WW2 circa 1943/44. What happened?


Kaman still builds a helicopter with intermeshing rotors: The Kaman
K-max, specifically designed to carry underslung loads for logging and
construction work. It has also been evaluated by the US Navy for use in
VERTREP missions and AFAIK Kaman is currently planning an unmanned
version for military work.

The German helicopter with intermeshing rotors was most likely the
Flettner Kolobri. The helicopters designed by Focke (not Focker) used
non-intermeshing twin rotors (side by-side).

BTW Fokker (also not Focker) never nuilt helicopters and at the time of
WW II had moved his business back to The Netherlands.

Regards,
Ralph Savelsberg

BTW Fokker (also not Focker) never nuilt helicopters and at the time of
WW II had moved his business back to The Netherlands.

Regards,
Ralph Savelsberg


Fokker does now as a contributing partner to the NH-90:


ww.globalsecurity.org/military/world/europe/images/nh90-731.jpg

Rob

(Peter Stickney) wrote:

They weren't fast, but
they sure were slow.




Reminds me of the guy describing his steak "Well it wasn't
particularly tasty but it certainly was extremely tough"
--

-Gord.

BTW Fokker (also not Focker) never nuilt helicopters and at the time of
WW II had moved his business back to The Netherlands.

Regards,
Ralph Savelsberg

Fokker also had the XA-7 aircraft prototype for the US:


http://www.wpafb.af.mil/museum/resea...k/a2/xa7-3.jpg

Rob

robert arndt wrote:

BTW Fokker (also not Focker) never built helicopters and at the time of
WW II had moved his business back to The Netherlands.

Regards,
Ralph Savelsberg



Fokker does now as a contributing partner to the NH-90:


ww.globalsecurity.org/military/world/europe/images/nh90-731.jpg

Rob


Fokker, as in Anthony Fokker, never built helicopters.

The few remnants of his once thriving company, which although it built
rather nifty airliners had financial trouble and ultimately went
bankrupt sometime in the `ninetees, indeed survive by working as
sub-contractors for various projects, including on the NH-90.
Saying that Fokker builds Helicopters is like saying Messier-Bugatti
builds planes (for those of you who don't know, they do hydraulics for
landing gears, for instance).


Regards,
Ralph Savelsberg

robert arndt wrote:

BTW Fokker (also not Focker) never nuilt helicopters and at the
time of WW II had moved his business back to The Netherlands.

Regards, Ralph Savelsberg


Fokker also had the XA-7 aircraft prototype for the US:


http://www.wpafb.af.mil/museum/resea...k/a2/xa7-3.jpg

Rob

Indeed Fokker's company, after returning to the Netherlands from Germany
post WW I, sold quite a few planes outside of the country. My remark was
merely intended to point out that the German Focker helicopter (sic.)
referred to by an earlier had nothing to do with the Fokker company in
The Netherlands.

Regards,
Ralph Savelsberg

Ralph Savelsberg wrote in message ...
robert arndt wrote:

BTW Fokker (also not Focker) never built helicopters and at the time of
WW II had moved his business back to The Netherlands.

Regards,
Ralph Savelsberg



Fokker does now as a contributing partner to the NH-90:


ww.globalsecurity.org/military/world/europe/images/nh90-731.jpg

Rob


Fokker, as in Anthony Fokker, never built helicopters.

The few remnants of his once thriving company, which although it built
rather nifty airliners had financial trouble and ultimately went
bankrupt sometime in the `ninetees, indeed survive by working as
sub-contractors for various projects, including on the NH-90.
Saying that Fokker builds Helicopters is like saying Messier-Bugatti
builds planes (for those of you who don't know, they do hydraulics for
landing gears, for instance).


Regards,
Ralph Savelsberg

On small historical correction Ralph. Anthony Fokker, together with
Stork, helped build the Baumhauer helicopter in 1925. It was the
Netherlands first helicopter.

Rob