Mailing List flyrotary@lancaironline.net Message #52555
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Prop Trim
Date: Fri, 15 Oct 2010 11:31:34 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Here an update. 
 
Sam Hodges informed that Catto was going to make him a new prop - same diameter 76" but reduce the prop area by 30%.  My back of the envelope calculations indicates that should give Sam what he needs for his Renesis
 
His first Catto prop was 8" in chord at its widest.  So 8" x 76" = 608 Sq inch (assuming same chord entire diam - which of course it is not, but again back of envelop), this was simply way too much prop even for a 220HP engine
 
A 30% reduction in prop area = 608 - (608 *.30) = 608 - 182 = 425 sq inch / 76 = 5.6" chord width.  That is just a tad wider (1/10th inch) than my 74x88 Performance Prop, so give Sam's Renesis will likely produce 10-15HP more with 2" longer diameter, this one should work out fine.
 
Ed
 
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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