# Apache Helicopter

I don't know if this is the right Topic, but I think it is, it has something to do with science.

I was curious if anyone knows how fast the propellers of an Apache helicopter go, like RPM's a minute or whatever, and how long are they, I guess if you could tell me the total (wingspan?) that would be okay.

I asked my parents this and they said just write on your homework, "Really damn fast and pretty damn big.", so if you think the same thing I am going to tell you the samething I told them.

This is not a homework problem!  I am just curious, I had an idea.  If this is not good enough for you, then I will come up with an excuse.  I am coming up with a very hard Calculus problem that I am trying to stump my friend with.  How's that?

Mark
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Commented:
The rotor speed is 4.86 Hz according to http://www.vibrationdata.com/Newsletters/April2003_NL.pdf

This translates to 292 RPM, consistent with the 289 RPM used in this simulation of the Apache's rotor system:

http://www.lions.odu.edu/~dkunz/conf/2001ApacheRotorRSC.pdf

The rotor diameter is 14.63 m, according to http://www.zap16.com/mil%20fact/ah-64%20apache.htm

That gives a rotor tip speed of about 4.86 * (2 * 3.14 * 14.63) = 447 m/s = 1000 mph

-Seth

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Commented: