Sizing Control Surfaces - Recommendations

[WrongBrother]

Hi All,

I hate to admit this but I have gone through getting a BS and MS in Aerospace Engineering and other than some "guidelines" and "ballpark numbers", I have not seen anything on the proper way of sizing control surfaces. The guidelines I have used in the past are:

For ailerons: 1/3 span, 20% of chord,
For Rudder: full vertical tail span, 30% chord (of v-tail)
For Elevator: same as the rudder but using h-tail chord and span.

I have recently designed a small r/c plane and while the control surfaces "look" right it just seems to me that there should be something out there - like a book - that talks about the proper way to size these.

Here are a few of the books that I have consulted wihtout much luck:

Perkins & Hage, Roskam (design series and S&C blue text), Raymer and Nelson

Thank you in advance!

 

[i278]

WrongBrother,

NACA TN-721 is the classic material from which (it seems) all else is based. It's directly applicable to tail surfaces. Ailerons seem to be ballparked, as 'adequate' and 'inadequate' roll is very subjective and can cover a large range.

TN-721 (like all good things) is available for download on the NACA Technical Reports Server.

Regards

 

[i278]

WrongBrother,

Sorry, mixed up the numbers off the top of my head. It's NACA Report 721, or NACA TN-796. I believe they're both the same thing, both from 1941, and both titled:

"Determination of control-surface characteristics from NACA plain-flap and tab data"

That should be enough info to find it on NTRS's 'new and de-improved' search engine.

Regards