Mailing List flyrotary@lancaironline.net Message #2978
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] Re: Good news, Bad news
Date: Sun, 14 Sep 2003 13:28:46 -0500
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message
What is the ratio/relationship in size of the prop to BUC?  Might be a good reference for something to look out for. 
 
Barny
 
BUC is much larger at the bottom, than anywhere else.  I would guess that the last 14 inches of my 68 inch prop extent beyond the cavernous inlet opening.   This is no doubt helping with my cooling, but has also got to be blocking some thrust. 
 
 
What's your fuel flow? (ultimate test) If you are tuned even half right,
fuel flow will approximate hp.

Charlie 

I wish I knew.  Tracy has been holding my flow meter hostage since June :-)

Rusty, I think the prop adjustment is the culprit.. (in addition to the piggy factor) Try moving the pitch to about 20 degrees measured at 75% of radius.  Compare the results to the more fine setting and you may discover you are generating a lot of power but not enough thrust with the current setting of 12-14 degrees. 

Tommy<>< 
 
I don't believe the prop is completely flat on the back side, with the exception of the very tip.  Warp sends a protractor with every prop, and it's meant to be used only at the very tip.  Basically, you zero the protractor on the hub face, dial in the pitch you want in degrees, then twist the blade to match that pitch.  The number itself is irrelevant to anyone but Warp, but it's a repeatable measurement.  
 
Cheers,
Rusty
 
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