On 2017-08-25 18:03:55 +0000, "Byker" <byker@do~rag.net> said:
> "Miloch" wrote in message news:onnlt901499@drn.newsguy.com...
>
> In article <dcCdnUh05bVozALEnZ2dnUU7-RHNnZ2d@supernews.com>, Byker says...
>>
>> "Miloch" wrote in message news:oni3ug01ili@drn.newsguy.com...
>>>
>>> Flying rule of thumb:
>>>
>>> "Anytime you can walk away from a landing...it was a good landing".
>>
>> After seeing so many crashes attributable to tail rotor failure, I wonder
>> why there aren't more twin-rotor manufacturers, like Kaman and Kamov?
>
> Interesting observation:
>
> "The US uses tandem rotor helicopters because they are easier to make
> and maintain; its biggest requirement is a sophisticated transmission
> design that needs to be placed between the two rotors to ensure they
> rotate evenly and the blades never intersect (even when one engine
> fails).
>
> "Co-axial helicopters are much harder to make and the entire engine and
> rotor design is extremely mechanically complex.
>
> "Just building a regular engine axel is difficult, and the finished
> axel is virtually impossible to inspect for internal voids or cracks.
> Any internal defects will result in a catastrophic failure when the
> engines spins up to speed the first time. Even now, many turbine engine
> manufacturers do their first engine start in something that looks like
> a giant steel bunker because there's just no way to be sure the axel at
> the heart of that engine won't explode; literally explode. You want to
> make axels that go inside axels and spin in opposite directions? That's
> a lot harder...
>
> "Personally, I have no idea why Russia chose such a complex and
> difficult to manufacture helicopter design. Igor Markov may be able to
> explain the logic behind that decision. He is very knowledgeable about
> Russia and has written some of my favorite Quora answers about that
> part of the world. I'm sure there is a reason; I just don't know it.
>
> "Personally, it reminds me of the Russian booster rocket designs from
> the race to the moon. The US built the Saturn V stage 1 rocket with
> five engines that had to fire simultaneously and equally. The Russians
> designed the N1 lunar rocket that contained 30 (smaller) engines in
> stage 1 that had to fire simultaneously and equally. The Americans got
> the the moon first (in part) because it's much easier to control and
> balance 5 engines simultaneously than it is to control and balance 30
> simultaneously."
>
> https://www.quora.com/Why-hasnt-Russia-commercially-produced-any-tandem-rotor-helicopter-and-USA-any-co-axial-rotor-helicopter
I
>
don't believe the K-Max K-1200 is dependant on a co-axial system, but
uses an inter-meshing "eggbeater" dual rotor.
<http://www.kaman.com/aerosystems/solutions/air-vehicles-mro/k-max>
<http://fireaviation.com/tag/k-max/>
<http://www.flyingmag.com/aircraft/helicopters/kaman-restarting-k-max-k-1200-production>
<https://youtu.be/4dJyUFgY0a8>
--
Regards,
Savageduck
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