Hi there guys,

I am building a model designed by Alex Weiss which uses a flat plate airfoil wing. Now in his book, he says that a model can be scaled either up or down and if you keep to the original planform and proportions of the designer it will not seriously affect the flight characteristics of the model. Im planning to scale his design up about 25 % and would like help on the following.

1/ The original main wing is made from 1/4 in sheet balsa.

2/ I wanted to make a slightly thicker wing say using foam core with balsa sheeting each side, but the thickness would end up about 1/2 in.

As long as I keep it flat in section, would the extra thickness of the wing make a big difference?

Thanks for any help,

John

I believe it would.....extra drag......but I don't know how much
good luck

Hi, if you to SPAD to The bone .com , you will see planes made of sign post plastic material called aircore. Some of these planes have flat wings called Stop Signs and Pizza Box . They are fairly good flyers. You may get some good ideas, RCU has some forums on SPAD airplanes that may help also. Easy material to work with and a lot cheaper than balsa.Remenber the .049 planes for U-Control years ago ? They mostly used flat wings and flew good. I have been toying with these planes for a while, once you get a good design you are going to have a lot of fun. Watch you center of gravity closely to make a good flyer. Have fun let me know how it works out for you. Thanks Dan

I have flown huge deltas [ six foot span ] with one inch thick foam / brown paper flat plate sections. No problems.

It's going to be too easy to create a wing that is slightly larger but quite a bit heavier.

If you do choose to sheet both sides of foam board, then by all means cut lightening holes in the board. Either cut lots of holes or large ones. And use the lightest balsa for sheeting you can find. It's not easy to find in the thinner sizes. You might want to cut the holes in a pattern that leaves a continuous line of foam from root to tip where a wing spar would be. The wing needs a spanwise strength and history has proven the spar as the solution. I'd cut a row of smaller lightening holes forward of the "spar" and larger oblong ones aft. Make the board look somewhat like a built up wing before covering. The idea is to support the skins with ribs and spar just as in any other type of construction.

Foam board isn't as light as it seems. And air is absolutely lighter.

Thanks to everyone for your help and info. Im just going to check out the SPAD site.

Cheers, John