"Miloch" wrote in message news:onnlt901499@drn.newsguy.com...
In article <dcCdnUh05bVozALEnZ2dnUU7-RHNnZ2d@supernews.com>, Byker says...
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>"Miloch" wrote in message news:oni3ug01ili@drn.newsguy.com...
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>> 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
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