prop formula - another thought

[Chuck Wagoner]

Try this link under "Goodies" for a free and apparently comprehensive
program with references
(under the help menu) that might be of interest to you all:

http://www.bmaps.net/

Any comments?

Chuck, NSRCA 115, KA8IZZ

=============
----- Original Message ----- 
From: "Kenneth Blackwell" <kblackw at adelphia.net>
To: <discussion at nsrca.org>
Sent: Wednesday, October 20, 2004 1:16 PM
Subject: prop formula - another thought


> I've been watching the discussion about prop formula.....i.e equivalency
> between 2-3-4 blades etc.
>
> So far the discussion and calculations have just covered diameter, pitch
and
> number of blades. However, there has been no mention of blade planform. As
> you know APC makes blades with all sorts of planforms wide, narrow,
> standard. In addition as you progress from one style prop (sport, pattern,
> etc.) the planform distribution differes wildly. A prop is just a rotating
> wing with a particular planform. Some are wide giving more planform area
for
> the same diameter while some are narrower. Obviously the two will provide
a
> different load on the engine. So, the only way that you could correlate
the
> load expectation between 2-3-4 bladed props would be with those of similar
> planforms.
>
> You may use a formula to get you in the ball park or maybe the parking
lot,
> but in the end you will just have to spend some bucks and try a size or
two
> to see what works for you and your engine.
>
> Cheers,
>
> Ken Blackwell
>
> =====================================
> # To be removed from this list, go to http://www.nsrca.org/discussionA.htm
> and follow the instructions.
>



---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.777 / Virus Database: 524 - Release Date: 10/14/04

=====================================
# To be removed from this list, go to http://www.nsrca.org/discussionA.htm
and follow the instructions.