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Engine basics => Engine set up tips => Topic started by: John Castle on February 05, 2009, 12:09:33 PM

Title: Trimming props
Post by: John Castle on February 05, 2009, 12:09:33 PM

I have several 6x3 props that I want to trim to 5" for use on 1/2a engines. I have never trimmed props before, do you have any suggestions before I proceed?

Thanks,
John

Title: Re: Trimming props
Post by: Jim Thomerson on February 05, 2009, 12:57:08 PM

I've flown Master Airscrew 6 x 3  props trimmed to 5 1/2 just by cutting off the tips.  Make sure the prop is balanced and it should work fine. 

Title: Re: Trimming props
Post by: Mark Scarborough on February 05, 2009, 02:54:01 PM

I make a stick with a 1/4 bolt in it, then you can trim one end of the prop, mark it on the stick, spin the prop and mark the other tip to make sure you get them the same.
I also prefer to sand the tips off on a belt sander instead of cutting them, but then i am using wood props too,

Title: Re: Trimming props
Post by: John Castle on February 05, 2009, 03:14:56 PM

Quote from: Mark Scarborough on February 05, 2009, 02:54:01 PM

I make a stick with a 1/4 bolt in it, then you can trim one end of the prop, mark it on the stick, spin the prop and mark the other tip to make sure you get them the same.

I like that idea. Do some of you do any shaping to the new tip or do you just leave it square?

Title: Re: Trimming props
Post by: Mark Scarborough on February 05, 2009, 05:21:54 PM

I have been reworking all my wood props at the tip to replicate the APC planform, that being the leading edge tapers back to a semi point shape
seems to work well on the APC which is a very good prop so why not on my tweaked ones

Title: Re: Trimming props
Post by: Steve Helmick on February 05, 2009, 08:52:17 PM

I've trimmed some APC's (12.25 x 3.75's and 12-5's to 11.5") and reshaped the tip to resemble the OEM tip...seemed to work very well. Scraping and sanding work ok, but your final sandpaper has to be uberfine grit. Wet would probably help, but I haven't tried it. You need to get rid of all the fuzz. Fuzzy is an inefficient tip shape.   D>K Steve