Has anyone scaled a set of plans from .40 to .60 size aircraft? If so, what % did you scale up by?

Scaling up or down more than just a few % will sometimes require a different engineering of the structure. IE, you don't want a landing gear support designed around 4 lb plane trying to to the job on a 12 lb plane. Also remember that increasing the size by say 25% will probably increase the weight by 50% to 60%. If you just blow up the plans by 25%, then the 1/4" wide stringers are now 5/16". That example lets you off the hook, but if it were 1/8", the new size will be 5/32', so now the stock is going to be harder tofind. You might stay with the 1/8", but the notches in the resized formers will now be to wide by 1/32". Next stock size is going to be 3/16, so now the notches are to narrow by 1/32". These are the issues you will run into

Is it worth the trouble? Sure is if youfind aplane you really like, build, but itis to small. It takes some work. If you think it though, it should give you a plane that will fly well. There are a lot of places to screwup though.

Iguess a commercial example would be the 4* kits. All three look exactly alike other than size.The kit design is different between the three though. The wingsarea good example.It would be a worthwhile project finding a set of 4*40, 4*60, and 4*120 plans and comparing the changes. It's way different than making every thing a % bigger, but once you know what you are in for, it can be a fun project.

Don</p>

A SIG 4 *40 is 59" span and a 4*60 is 71" span. 71/59 = 1.20 The 59" span model increased by ~120% is 71" span. If you take very similar models that have different engine sizes as in this example and calculate thus is this the info you were seeking? A previous post has stated pertinent info, also. Good luck.

I go into Kinko's and use the % meter, I used to have one of my own when I was still working as a printer. Plane is this size, want it this size, turn the wheel and shazam, here is the % needed to do it for you. Next time I go back to visit my old work place I plan on getting another meter for my own use. So much easier then doing all that thinking and using up those brain cells!! If you have a small kit and want to make it bigger then make templates of all the parts and have them copied at the same time as the plans so they are the correct size, the machines can be off a little from set up to set up. Not a big deal but you may as well have it all done correctly first time.