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Old 03-21-2020, 08:44 PM
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tedsander
 
Join Date: Jul 2004
Location: White Bear lake, MN
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No help on the foam board question, I've just started to explore building with that. Although I have designed and built planes for over 50 years....

As for the second question...ummm, that really, really quickly gets you in to the vast field of aerodynamics. The width to span is called "aspect ratio". It can vary a LOT, depending on the type of flight you are designing for. Look at sailplanes vs jets. And no, it's not just slow vs fast....
Since you are posting in the Beginner column, best advice - STEAL. Look for a plane that is pretty close to what you want yours to look like. Best if you can find a picture looking down from the top. From a printout, or even on your monitor, measure the wingspan, then measure the width ("chord" in aerodynamic terms). Let's say you get a 5" span, and 1" width. That aspect ratio is 5:1
If you got oddball numbers, like a span of 6.75 and a chord of 1 3/8, divide both numbers by the width to get the right side of the ratio down to "1". 6.75/1.375 = 4.9 and 1.375/1.375 = 1, so pretty close to 5:1
For your design, if you want your wingspan to be 50", divide that by the "5" in the 5:1 ratio. Width would then be 10". Don't worry about being all that precise.

Get this book, as an introduction to aircraft design, if you want to know more about the whys. One of the best intros to design ever published:
Amazon Amazon
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