Mailing List flyrotary@lancaironline.net Message #52500
From: Jeff Whaley <jwhaley@datacast.com>
Subject: Another prop performance calculator
Date: Fri, 8 Oct 2010 17:41:22 -0700
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Ed, with my prop numbers (74"x 58", 4 blades, 59F, 6100 engine rpm or 2140 prop rpm) entered into this calculator it says I'm making 196 hp static ... seems hard to believe.
I've always wondered what the difference is between 4 blades Vs 2 ... the same numbers with 2 blades gives 117 hp..
Also, my prop is a Warp Drive and the pitch is measured at the tip ... don't most prop manufacturers specify pitch at 75-80% of diameter?
Wish I had been in Paducah to bolt your prop on and see what happened ...
Jeff
 
 
From: "Ed Anderson" <eanderson@carolina.rr.com>
Subject: Another Prop Performance Calculator
Date: Fri, 8 Oct 2010 19:06:16 -0400
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Here is a link to a STATIC performance calculator that seems to at least give reasonable results
 
 
I could turn 5800 rpm static when my prop was 76x88 which this calculator indicates the engine was producing 168.1 HP to turn the prop 2035 rpm
 
When I trimmed the prop back to 74x88 I picked up 200 static  engine rpm which this calculator then indicated the engine was producing167.2 HP to turn the prop 2105 rpm
 
So between 165 and 170 HP seems reasonable.
 
 
 
Edward L. Anderson
Anderson Electronic Enterprises LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com

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