Re: Re: Rubber comnparison

From: Kevin Lamers <kevin.lamers_at_gmail.com>
Date: Thu, 13 Feb 2014 15:31:28 +0100

I was talking about a prop with a bigger diameter but with the same thrust
and moment coefficients. In a VD prop this is not true, because you
increase the diameter but not change the dimension of the blade and pitch
distribution.
Therefore, a small fast turning prop, or a slow turning prop with more
blades is less efficient than a large prop with 2 blades (thus assuming
they are all designed for the same flight condition).

Kevin


2014-02-13 14:18 GMT+01:00 <mkirda_at_sbcglobal.net>:

>
>
> Hi Kevin.
>
> In the one VD prop I built, the 21" larger diameter made the plane fly
> with between a 30-45 degree bank. It may have been extraordinarily
> efficient, but the plane flew terribly. I suspect another inch or so of
> wing offset would be needed to handle the torque on the airframe.
>
> This is one of the theory things that, while true, may not work out in
> practice due to other considerations.
> Regards.
> Mike Kirda
>
>
Received on Thu Feb 13 2014 - 06:31:29 CET