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Engine basics => Engine set up tips => Topic started by: Dennis Toth on July 06, 2014, 06:42:29 PM
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Guys,
Wondering what methods you have used to trim APC props to smaller diameters? I have used a stick gauge that Windy came up with (a piece of motor mount with the 1/4" bolt in one end with different lengths marked down it). This is a simple way to get both blades the same length.
Now this gets the correct diameter. What I have seen is the tip shapes and airfoil shape at the cut end can cause loss of performance vs. the original molded tip. Anyone find a method to keep the APC prop performance when cutting them down?
Bests, DennisT
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Well, I needed an 11.5" diameter prop, starting from a 12.25 x 3.75 APC (see picture) for my piped .46VF. I first had to drill out the center hole to fit a .250" dowel pin, and then made a template out of poster board. Scribed around the periphery (bottom surface) with a #11 (indexing off the hole and TE). Belt sander took the outline to the scribe lines, and I started scraping the top of the prop with a fairly sharp knife blade. I found out the APC material will actually file quite decently, but scraping works great, followed by a little sanding, balancing, and polishing. Works fine!
But yes, the next step is some 3 blade Brian Ether flat backs or maybe an UC. We'll see on that. But for now, I've got a pretty useful baseline prop. H^^ Steve
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Get a prop scribe, and use a fine tooth metal hacksaw blade in one of the small blade handles, Stanley and other make them and you can get them from Walmart of most hardware stores
Randy