fitball

Considering only exterior dimensions and airfoils does a full size plan scale uniformly to model size?
What exceptions are most likely? Are plans mostly scalable on a case-by-case basis? Any case guidelines?
Thanks,
John

pmullen503

It depends. Usually, you need to increase the relative size of the horizontal and vertical stabilizers. Pre WWII civilian aircraft can usually get by with scale tail surfaces though you often will want to increase aileron size. Military aircraft, or anything where performance is more important than stability will often benefit from and increase in tail size.

I usually go with the NACA 24XX series of airfoils for models. Reasonable L/D, mild stall, OK inverted performance. Clark Y isn't a bad choice but not for even mild aerobatics.

fitball

Thanks for the useful info.
Tiny mach numbers call for more substantial controls.

solentlife

I find that pre war and wartime (WW1 ans 2) .... have usually small tail planes - particularly stab and elevators. You find that model kits / ARF's often have scaled up horizontal surfaces for that reason.

I have used 3 views of full size ... - just added formers / bulkheads as I thought fit ... as to wings and aerofoil ... plumped for Clark Y or a Semi-Symet and never worried what NACA design it was.

I do have a book full of Aerofoils with tables of measurements etc. - but haven't got that out for many years .... I used to have an excel sheet that I could enter co-ords into ... lost that many years ago.