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Old Mar 08, 2003, 09:53 PM
Will work for planes
omega blood's Avatar
Fullerton, California, United States
Joined Jan 2002
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Question
Wash out and foamboard wing?

How critaical is for a sloper to have wash out? I've built and flown planes with out wash out before,(before I knew what wash out was or that even existed) but they had dihedral and were canstant cord wings. For my next project I want to make a taimpered wing out of foam board ( not a flying wing mind you) . since you realy can't put washout into the wing how would affect performance on the slope? Would it have a bad tendincy to tip-stall?
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Old Mar 09, 2003, 11:19 PM
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Keremeos BC Canada
Joined Dec 2002
369 Posts
Has to do with wing plan

Look at it this way: if the wing is constant chord, the washout will be zero. If you cut the leading part to the spar (or break) constant chord but cut a taper towards the tip of the trailing edge, the washout is automatic. The steeper the taper, the more washout. I did some experiments years ago on this with 3" wide balsa f/f, and the best results were 1" le to break, then 2" wide 50% towrds the tip, tapering to 1". Never any sign of tipstall.

Cardboard is Cheap!
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Old Mar 10, 2003, 07:00 AM
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Hervey Bay, Sunny Qld, Australia
Joined Jun 2001
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Re: Wash out and foamboard wing?

Quote:
Originally posted by omega blood
For my next project I want to make a taimpered wing out of foam board ( not a flying wing mind you) . since you realy can't put washout into the wing how would affect performance on the slope? [/B]
You can build washout into any wing regardless of how it is made. I take it that you are going to be baking the foamboard wing (???) Or are you referring to coroplast board? Either way you should be able to build in the washout. Wash out as you'll already know is used to help make the plane easier to recover from a stall, as well as reduce tip stalling.

Later,
Glen
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Old Mar 10, 2003, 08:36 PM
Will work for planes
omega blood's Avatar
Fullerton, California, United States
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Thanks for the info T.
As for baking the wing masterpiece my oven is too small. I was planing on folding one piece over the other with a balsa spar to form the airfoil. I may try puiting some ribs in and building in the washout as you suggested.
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Old Mar 11, 2003, 06:48 AM
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Hervey Bay, Sunny Qld, Australia
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Quote:
Originally posted by omega blood
Thanks for the info T.
As for baking the wing masterpiece my oven is too small.
Fair enough . Good luck with it and I hope it comes out well.
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Old Mar 11, 2003, 08:02 PM
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Keremeos BC Canada
Joined Dec 2002
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Personally...

...I would play with cardboard (cheap, usually free) until you get the shape/washout/airfoil/ whatever that you are looking for before you commit to foamboard. The results are going to be identical except for the slight variation in weight. Waterproofing the cardboard is easy, I've used all kinds of dopes and urethanes to finish it. Most times packing tape is all you need for an adhesive, particularly for experimental purposes.

Express yourself!
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Old Mar 12, 2003, 03:56 AM
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Fullerton, California, United States
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Oh, thats what you ment by " cardboard is cheap". Thanks T, I will do that since they throw out alot of cardboard at my work place.
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