flyrotary@lancaironline.net Mailing List Archive

From Pat - appears my problem is not "slippage" but negative Thrust - well, negative thrust does not sound very positive to me. Now If I had it installed as a pusher prop would I pick up 4 MPH in airspeed - with the negative thrust now in the pushing direction {:>)

From: Pat Panzera

Sent: Saturday, October 09, 2010 1:45 PM

To: eanderson@carolina.rr.com

Subject: Re: [FlyRotary] Effective Prop Pitch Calculations

Please forward this thought for me:

No slippage, your root section is creating negative thrust since it's not pitched steep enough.

On Sat, Oct 9, 2010 at 10:16 AM, Ed Anderson <eanderson@carolina.rr.com> wrote:

I used the equation that Lipps mentions in the article in CONTACT! to Calculate "Effective Pitch" of my 74x88 prop. His equation (with some clarifying annotations) is

Effective Pitch ( % ) = TAS (mph) *1056/RPM(Props' RPM not engine)

EF = 168*1056/2105 = 84.27 effective pitch

Since my Props pitch is suppose to be 88" could this mean I have a bit of "Slippage"? Actually, I was impressed that the calculation came out as close as it did - within 4% of its 88" of pitch.

Thanks Pat

Ed

Edward L. Anderson
Anderson Electronic Enterprises LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com