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Weird rotor configuration


mclrn227
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I was just watching the history channel and they had a show on about heli-logging. One of the helicopters they showed for just a second had a rotor setup I'd never seen before. I searched for a long time and came up with nothing. I'm curious now and would like to find out more, or just browse other pictures. The best way I could describe it was to just draw it. It was like two rotor heads at an angle, but next to each other. They alternate like a sikorsky's rotors. Anyone know what the heck that was?

 

crossi.jpg

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The K-Max is a single-place machine. There are no training models. You have to fly it by yourself the first time, so rookies need not apply.

 

There must be simulators though?

 

 

I would think a dual rotor design like that would lose efficiency because of the way those blades are angled. Plus, wouldn't the downwash of effect the one below it?

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Training is done in the Husky, if Kaman's Husky hasn't completely timed out yet. Still flies like a helicopter though, just has a few operational quirks to watch out for. For example, the controls are backwards if your are at low collective settings under power. Things like that. ;)

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No simulators that I know of. Huskies aren't readily available. I know a couple of guys who have flown them, and after a ground class, they were just put in the cockpit. They did have well over 10,000 hours of helicopter time, though, including a lot of long-line time.

Edited by Gomer Pylot
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The angle between the rotors is 25 degrees. Thus the angle each one is off of vertical is 12.5 degrees.

 

The cosine of 0 (degrees off of vertical) is 1, thus 100% of the thrust is down. The cosine of 12.5 degrees is .9763 So, 97.63% of the rotor's thrust is going straight down. Take, 100-97.63=2.37.. thus a mere 2.37% of the thrust is lost going sideways. The fact that you have two rotors has no bearing on the efficiency calculation.

 

According to the people here, a conventional open tail rotor consumes 10-15% of the engine's power, and the Fenestron (fan tail) consumes upto 25%.

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Hi

 

Yeah it is called a syncro-mesh rotor system, Kaman called them synchropters.

 

The KMAX is a beast and doesn't have the greatest safety record around (I'll attribute that to the flight profile that it lives its life in and a lack of a proper training platform)

 

It is reported that a total of 38 K-1200 K-MAX helicopters are known to have been built, of which 14 are now un-flyable or have been written off in accidents.

 

There is a ROV variant

 

I can't seem to confirm it, but if I recall what I read properly I believe that production on the KMAX has ceased.

 

Regards,

IFlySky5

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I believe that design was originally a German design called the Fletner system. Designed during the 2nd World War. Quite efficient was there is no tail rotor stealing power from the engine. Weight and complexity are the two major negatives in the system.

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