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Matt Dralle's RV-8 Project
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Date: 8-30-2009
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Number of Hours: 1.00
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Manual Reference:
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Brief Description: Constant Speed Prop Spinner Installation - Part 01
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Installing and fabricating the spinner installation on the Hartzell 72" constant speed prop was a little more work than I thought it was going to be. The only cutout pattern I could find was for the blades was a similar, but not exactly the same Hartzell prop. Because the blades on the prop twist depending on the prop setting, the cutouts in the spinner have to be sufficiently large to allow for the rotating action. But, the holes can't be excessively large as to cause undo drag or just plain unsightliness. So, I started with the template which got me kind of close. I then just filed a little more away, tried it on, filed a little more, etc. etc. etc. I had to strap two long boards onto one of the prop blades so that I could rotate the prop through the min and max pitch modes. The spring inside is designed to force the prop into takeoff configuration if there is a loss of hydraulic pressure. And that spring is STRONG. The 4' boards helped a lot in being able to test the spinner hole size across the various pitch settings.
Once the front side of the spinner was done, you then have to fabricate - FROM SCRATCH - two .063" metal inserts for the backside of the prop. I used one of those carpenter duplicators to get a full-swing indication of what the insert had to be shaped like. There are then two little flanges that have to be fabricated and riveted to the side to allow an attachment screwed be added later. Once the inserts were fitted and fabricated, they had to be riveted directly to the spinner backplate.
Finally, there are 21 screws that hold the spinner onto the backplates. This means that there are 21 nutplates that have to be drilled on and installed which seems like it takes forever...
I am extremely please to report that the spinner fit over the inserts came out PERFECT. Also, the prop blade holes are just about the perfect size and give about a .100" clearance minimum across the full swing of the blade pitch. The spinner also seems to track very accurately when the prop is turned.
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How To Find The Exact Middle Of The Spinner
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How To Find The Exact Middle Of The Spinner
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Hartzell Template As A Starting Point
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Copyright © 2008-2024 Matt Dralle. All Rights Reserved.
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