Talk:Momentum theory

	Physics portal This article is within the scope of WikiProject Physics, a collaborative effort to improve the coverage of Physics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.PhysicsWikipedia:WikiProject PhysicsTemplate:WikiProject Physicsphysics articles
Low	This article has been rated as Low-importance on the project's importance scale.
	This article is supported by Fluid Dynamics Taskforce.

Aviation: Rotorcraft

	Aviation portal This article is within the scope of the Aviation WikiProject. If you would like to participate, please visit the project page, where you can join the project and see lists of open tasks and task forces. To use this banner, please see the full instructions.AviationWikipedia:WikiProject AviationTemplate:WikiProject Aviationaviation articles
	This article is supported by the rotorcraft project.

Questions[edit]

Someone needs to add an example, including all the units - as it stands, this formula is unusable to us.

Does the density of the air, ρ, change when the rotors start spinning, or is ρ the density of the air (without the rotors)? Also, is the area the area of the entire circle (or "disk"?) encompassed by the spinning rotory wings, or is it the area of the actual rotor wings? BriEnBest (talk) 23:21, 24 January 2012 (UTC)[reply]

@BriEnBest - area is the swept area of the disc. Good question about the density! I'd guess is is without the effect of the rotors though, otherwise it's a constant in a formula which depends on its own formula, which would not make sense.

This article is complete fraud, genuine author of this formula is Andrija Radovic and the genuine derivation is available on http://www.andrijar.com/thrusters/index.html. This is flagrant violation of the true author’s copyright without any solid proof that Rankin has ever derived this formula. — Preceding unsigned comment added by 85.222.167.187 (talk) 23:00, 10 July 2013 (UTC)[reply]