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HomeAircraftHelicopterHelicopter Main Discussion › Math/Physic experts: How fast is max?
10-26-2006 04:42 PM  12 years agoPost 41
da_man

rrKey Veteran

Central NC

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I saw some people with basic equations, but it is more complicated than that. You need to either use actuator disk theory(easy) or blade element theory.

actuator disk theory, is a rough estimate and does not take into account the rotor dik properties, Assumes there is a complete disk with a pressure difference. Based on conservation of energy, mass, and momentum.

Vsubh=sqrt( weight/(rho(air density*disk area)) to get velocity of air to hover.

Power to hover= Weight*V subh

Power to climp(max)/power to hover = (V-climb/V subh)+sqrt(1+(V-climb/V subh)^2)

and solve for V-climb.


Blade element analysis involves the atual rotor design, which I am learning about now. It would give a much better estimate.

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10-26-2006 05:15 PM  12 years agoPost 42
AirWolfRC

rrProfessor

42½ N, 83½ W

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Is that in MPH, KPH or fps ?
And the answer is . . . . ?

Really, I'd like to know what your numbers say.

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10-26-2006 06:40 PM  12 years agoPost 43
w.pasman

rrElite Veteran

Netherlands

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V-climb
rho(air density*disk area)
Your formulas are confusing. First we want to go down so why use a climb speed formula?
Usually, rho IS the air density?
And then, is this talking about an Average air speed? In the middle there will be no air speed, and at the tips very high speeds.

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