Matt,
What I've been doing is a single layer of 3.5 oz CF cloth on 45 bias on BOTH sides of the blade. The torsional is greatly improved, and the spanwise strength is minimally improved (but I don't think greater spanwise strength is needed). I've not played with vacuum bagging, so I am using thick CA adher the cloth to prop. No doubt vacuum bagging would produce a nicer quality finish with less effort.
Regards,
Dave
ORIGINAL: MTK
Mark,
I believe Bryan does it on the apc nylon props just like dave Lockhart does. Dave discussed what he does with me a few months ago on his electric plastic props. He uses a combination of cloth on bias and mat nonwoven carbon. He only applied it on one side but to me there is even more benefit to apply the material on both sides.
I work with wood but laminated one plastic prop for Lochowski. My wood technique is straight forward....I buy XOAR electric wood props from Chief Aircraft and remove the finish. Then I epoxy a double layer of cloth, bias cut, to both sides. The layers are stretched a bit to increase the longetudinal component. Then I trim the cloth and get the balance close by removing some epoxy.
The assembly is then inserted into a top and bottom coccon made of 010'' mylar sheet, the edges are taped closed and the whole thing inserted into a vacuum bag. After curing, trim and balance as necessary. Very sprty outcome.
The wood electric props are required to save me trimming and shaping of the thicker glow/gas props. The XOAR prop has an outstanding shape very similar to apc, which to me are the best there is. The electric laminated woodies are being used in glow/gas applications. Weight wise the outcome is unequaled...a 19x8 is 60 grams and a 19x10 just 3 grams more. A 20x10 is only 80 grams and a 19x13, 75grams
After I've run some props for a few hundred flights with a little help from my friends, eventually I will write an article for Model Aviation when I get some time.
MattK