geoffreywh Posted July 14, 2014 Share Posted July 14, 2014 It's Winter. Having a wooden prop means a re-torque. While taking off the prop I was going to take the opportunity to crop it a bit and reduce the pitch a little......It's 69 x 54 which is too much pitch. I need about 200 more revs. Anyway, take the prop to the workshop. crop the tips by 3/4 inch and compare the cross sections now revealed. Shock/horror. about 5 mm difference in thickness!....If the tips are so different, what about the meaty bit? So I draw "stations" along the length of each blade at 50mm intervals. I compare thicknesses and camber high points. plus the "flatness" of the bottom airfoil......My goodness what a mess! The "flat" lower surface is almost semi symetrical!..The high point of the upper surface wanders from 30% to 55% of the chord. Mr Sweetapple must have had an off day when he made it....After 4 days of sanding. I have depitched the blades somewhat. Got the undersurface reasonably flat. Got the highest point of the airfoil at 38%-42% as far as possible. Now t0 recover the prop with glass. Anybody got an idea what weight of glass to use? I suspect 80g per sq mtr....Does anybody actually know????? Link to comment Share on other sites More sharing options...
AVOCET Posted July 25, 2014 Share Posted July 25, 2014 Have you found out yet ? If not give us a call 86484018 I've got a roll in the glass shop Cheers mike Link to comment Share on other sites More sharing options...
geoffreywh Posted July 25, 2014 Author Share Posted July 25, 2014 Thanks for the offer, I have used 80gsm cloth applied with epoxy, then filled with two pack epoxy varnish, came up beautiful. 1 Link to comment Share on other sites More sharing options...
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