Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Wed, 01 Jan 2003 23:26:52 -0500
Message-ID: <redirect-1943455@logan.com>
From: StarAerospace@aol.com
Subject: Re: [LML] Re: Scimitar Prop vs. Original Hartzell Prop - Comparison
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I am reminded here of the time when I did some drag reduction on an aircraft 
that the owner of the kit company felt was snake oil.  He proclaimed loudly 
and to everyone present (6 owners of this type) that I was full of s--- and 
virtually demanded that the improvements be removed.  The owner of the now 10 
KTAS faster aircraft merely shrugged and said:

"But Alan, it's faster!"

The effects of a prop switch are complex and without going into it all I can 
say that most of the assumptions I have seen quoted here on the original 
prop's qualities are in error and incomplete as are most of the equations 
being used to quantify the comparison.  If the prop in the real world made 
that much difference, then it is not the new owner's responsibility to 
mathematically "prove" his performance.  We have races for that.  If anyone 
wants to try to quantify this on paper and comes up with anything but the 
actual flight test numbers (within allowable test errors), then they either 
have inaccurate data, assumptions, and/or equations.

This experiment worked.  My congratulations to the owner and Hartzell.  Is it 
worth the extra cost and weight?  Only the individual owner can answer that.

Eric Ahlstrom