scale sizing
 

Help,
Maybe someone out there can help me. I plan on building a 1/4 scale model of a Benson type autogyro (gyrobee) , the frame is made from 2 in.sq.aluminum tubeing, so off the bat I figured 1/2 in. is one quarter of 2 inches and i would be useing 1/2 in. sq tubeing for the model. But then if you look at the end of a 2 in. sq tube , you would see that it is 4 sq inches in area, and 1/4 of that is one inch, so what should I use for the frame 1/2 inch or one inch tubeing .
Thanks
Donna.

Scaleing is liniar
 

Hello
Your first deduction is correct scale is linear not square or cubic. Could you imagine what you would get if you would try to scale down the displacement of the real engine? Try to figure it out and you will know what I mean.

This was a good question !
Otto Kudrna

scale sizing
 

Your initial choice is correct. Use a linear scale.

scale sizing
 

Thanks,
I already have 8ft of 1/2 inch sq. tubeing on order.
Donna.

scale sizing
 

Actually, there are uses for 3 dimensional scale. For example, if you wished to know what a 1/4 scale autogyro should weigh, or the what displacement of a 1/4 scale engine should be. You just need to remember to divide for length, width and height instead of just one of the planes of measurement.

If the full scale autogyro weighed 500 lbs., and you wanted a 1/4 scale weight, then you'd divide 500 by 4 for length, divide again by 4 for width, and once again by 4 for height, which would provide a 1/4 scale weight of 7.81 lbs.

Trivial, but perhaps useful someday. :)