Despite the obvious drawbacks of a larger rotor diameter would the reduced disc loading increase efficiency during hover and forward flight?

  • $\begingroup$ you said3 italic Despite the obvious drawbacks italic you probably should enumerate what the drawbacks you are talking about.Since I don't know which drawbacks you are thinking of, this question now reads Despite [any possible] drawback, ... to which the answer must be: hell yea, go fro it baby $\endgroup$ – jeff the tall Feb 23 at 0:09

Larger rotors means more weight, so the overall loading will be greater /even when/ the larger disk increases airframe's MTOW. So, there's a curve of where rotor blades provide the most lift force for their size (area) and relative airflow- a product of TAS, AoA, and RRPM, all of which can change independently and make blades more or less efficient in different flight configurations (i.e. most efficient at 0kts / 30kts / 80kts, etc...). I assume that the retreating blade stall forward speed reduces with larger blades because the tips of the blades are moving faster, and there's probably much more to take into account...

However, to make things much simpler, all this stuff is all done by the manufacturer, so just slapping larger blades onto your helicopter than what came out of the factory is very likely a very bad idea, and not just from a fuel efficiency standpoint.

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    $\begingroup$ Larger rotor means more weight, but it would have to be really humongous before the wait would grow faster than the area. The important thing is that larger rotor means more form drag. $\endgroup$ – Jan Hudec Feb 23 at 11:05

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