Mailing List flyrotary@lancaironline.net Message #55377
From: Ernest Christley <echristley@att.net>
Subject: Re: [FlyRotary] Re: Blower does work
Date: Mon, 20 Jun 2011 12:27:07 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Bill Bradburry wrote:
Ernest,

Do you have any pictures of this prop carving process?  That sounds interesting.


I didn't take any pictures, but I should have.

I got a cheap hand planar from Harbor Freight.  It has a guide attachment that mounts in the front.  I replaced that with a 12" length of 1/4" threaded rod.  I removed a case screw at the rear, and drill all the way through the case there with a 5/16" bit, replaced the screw with a 12" length of 5/16" threaded rod.

A half sheet (2' wide) of 3/4" plywood sitting on saw-horses.  Two 4' lenths of 1" steel angle.  I set the angle so that it bracketed the prop blank on each side along the length, and match drilled a 5/16" hole on each end of the angle through the plywood.  Bolted an 8" length of 5/16" threaded into each hole of the plywood.  That gave me a way to accurately adjust the height of each end of the steel angle, and the hand planar will slide along the steel edge on the rod (nuts on the planar's rod keep it from sliding sideways).

Good news is that it was a cheap and easy jig to build, and it gave me a quick and accurate pitch to the prop.  Bad news is that I only added enough pitch to barely pull on the airplane.  At 5000rpm, it would just barely start to pull the airplane uphill.
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