Re: Re: Prop Efficiency

From: Bill Gowen <b.gowen_at_earthlink.net>
Date: Mon, 28 Aug 2006 13:12:45 -0400

Amen Leroy!

  ----- Original Message -----
  From: LeRoy C Cordes
  To: Indoor_Construction_at_yahoogroups.com
  Sent: Monday, August 28, 2006 12:53 PM
  Subject: Re: [Indoor_Construction] Re: Prop Efficiency


  Apologies, guys but I just had to comment after biting my tongue for some
  time now - the word is chord - a cord is a piece of string.

  Pardon an old goat for speaking up but the info being passed on is so
  great I feel it should be properly defined.

  LeRoy Cordes
  AMA 16974
  Chicago, IL
  In God We Trust

  On Mon, 28 Aug 2006 04:22:40 -0000 "John Kagan" <john_kagan_at_hotmail.com>
  writes:
> --- In Indoor_Construction_at_yahoogroups.com, "markdrela" <drela@...>
> wrote:
> > I assume you mean 0.68, not 7.68.
>
> Typo...I actually meant .768 - even worse! Changing the velocity
> and
> then adjusting the cord back to the same size (after it produces a
> new "optimal" prop) doesn't seem to change the Cl much.
>
> After playing around a bit, I think I found the (or at least "a")
> problem: there is a small set of airfoils (with a specified Re) to
> choose from. I picked a 6% arc airfoil with a Re of 50,000 - the
> closest thing it had to an indoor airfoil. But I think the
> relatively
> high Re might be skewing things. At least I think this is the case
>
> because if I pick a different airfoil with an even higher Re, the Cl
>
> changes significantly - even though it seems to be calculating Re
> for
> the resulting prop.
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>

  LeRoy Cordes
  AMA 16974
  Chicago, IL
  In God We Trust


   

[Non-text portions of this message have been removed]
Received on Mon Aug 28 2006 - 10:15:38 CEST