11-19-2016, 12:05 PM
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When Pigs Fly!
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Join Date: Sep 2005
Location: Orlando, FL
Posts: 1,102
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Quote:
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Originally Posted by luke strawwalker
FOURTH, by using the "folded over the leading edge" technique (I detail in my Dr. Zooch Vanguard Eagle build thread) the paper is strongest where the aerodynamic loads on it are the strongest-- it's FOLDED OVER THE LEADING EDGE. Other techniques that are commonly used, using profile "cut-outs" of paper to "skin" the fins from BOTH SIDES, leave an exposed edge at the leading edge which the several hundred MPH slipstream of air rushing past the rocket is attempting to RIP OFF of the fin, making for a weak spot. Most of the delamination problems I've read about have come from people using "self-adhesive label paper" and other things with weak adhesives that are NOT THE BEST FOR PAPER AND WOOD BONDING APPLICATIONS and that leave an exposed edge where the slipstream can attack it in flight, and try to overcome this deficiency with CA "superglues" to essentially "nail" the paper down. If the paper is ONE PIECE that wraps OVER THE LEADING EDGE and then encapsulates BOTH SIDES of the fin, the only "seam" in the paper/glue joint is at the TRAILING EDGE, which the slipstream is PUSHING DOWN against the fin... I've NEVER had a white glue papered fin delaminate.
FIFTH, lots of people believe you have to use some "magic paper" or heavy duty cardstock to achieve any results... this is simply NOT TRUE and COUNTERPRODUCTIVE!!! I use ordinary Wal-Mart 60 pound PRINTER PAPER with perfect results.
Later! OL J R 
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JR,
Points 4 and 5 are very important!
I don't paper all the time but when I do -
Laying the paper over the leading edge is the best way to go! Round just the leading edge, don't round the outside and trailing edges. You end up with a easy rounded leading edge that has no chance of peeling off.
The outside and trailing edges remain square. The paper is easy to trim off and that remaining square sides are easier to fill.
I have better luck using a glue stick. For smaller fins, the glue stick is not as wet and a pretty good working time before it sets up. On larger fins I's probably go with the white glue.
Self adhesive label paper does lift. I remember my old Gyroc hinges coming up.
60 lb. weight paper is great for papering. 110 lb. card stock is too heavy. You don't want to add weight to the back of the model. |