Mailing List flyrotary@lancaironline.net Message #52522
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Solidity of Prop Disc
Date: Sat, 9 Oct 2010 19:30:41 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Some more interesting tidbits on Prop parameters
 
Regarding steps that could be taken after diameter and pitch parameters are considered for increasing thrust.   Increasing the blade chord or the number of blades. Both have the effect of increasing the solidity of the propeller disk. Solidity simply refers to the area of the propeller disk occupied by solid components  (the blades) versus that area open to the air flow. As solidity increases, a propeller can transfer more power to the air. (provide you have the power available - otherwise the increased load will diminish the prop/engine rpm resulting in less power and performance)
 
While increasing the blade chord is the easier option, it is less efficient because the aspect ratio of the blades is decreased resulting in some loss of aerodynamic efficiency.
 
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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