Thanks Rick
I measured the thrust with a large spring pull gauge, like you might use to weigh
a fish. The first gauge I used only measured up to 200 lbs so I hooked a pulley
to the tail of the Piet and ran a rope from the trailer hitch on my car,
through the pulley, and back to the gauge, which was also hooked to my trailer
hitch. Later I borrowed a 300 lb gauge and did away with the pulley. Both setups
gave the same readings and I verified the gauge readings by hanging myself
from a tree. No harm done! Good luck with your project and keep us posted on
your test run results. It sounds like your RPMs are very good for your prop and
it would be interesting to see what the thrust is.
Malcolm Morrison
----- Original Message -----
From: "Rick Holland" <at7000ft@gmail.com>
To: pietenpol-list@matronics.com
Sent: Friday, November 20, 2009 7:27:16 PM GMT -05:00 US/Canada Eastern
Subject: Re: static thrust
Good analysis work Malcolm. How did you measure your static thrust? I am also test
running a WW Corvair conversion but with an MA3 and get 2950 with a 66x30
Tennessee prop, running at 6700 ft. (around 18% less HP than sea level).
Rick
On Thu, Nov 19, 2009 at 8:37 PM, < gliderx5@comcast.net > wrote:
Dan
I have the results of my static thrust testing at http://home.comcast.net/~mmorrison123/engine_test.html . Corvair with a homemade prop. 2500 RPM static giving 280 lbs thrust. I spoke with William Wynne at Oshkosh, and he indicated that for a Piet I should be more like 2700 RPM and 350 lbs thrust. I may look at getting a Warp prop. It is highly likely that the factory can make a better prop than I can.
Malcolm Morrison
----- Original Message -----
From: helspersew@aol.com
To: pietenpol-list@matronics.com
Sent: Thursday, November 19, 2009 7:49:50 PM GMT -05:00 US/Canada Eastern
Subject: Re: static thrust
Gentlemen,
Has anyone done a static thrust test on their flying airplane (or almost flying?).
I have measured 265 lbs. with my Model A and my 76/46 prop. I would be curious
how this stands up to others.
Dan Helsper
Poplar Grove, IL.
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Rick Holland
Castle Rock, Colorado
"Logic is a wreath of pretty flowers, that smell bad"
