Does the "cg" change when you up scale the foam board plans?

Merv

Site Moderator
Staff member
As a percentage of wing cord, CG will stay the same. A 25-30% CG will work no matter the scale.

However, wing loading (oz/sqft) will change dramatically as the scale changes.
 

Stewienx

New member
As a percentage of wing cord, CG will stay the same. A 25-30% CG will work no matter the scale.

However, wing loading (oz/sqft) will change dramatically as the scale changes.

I'm trying to upscale the Ft alpha is that considered a wing?
 

Hai-Lee

Old and Bold RC PILOT
The balance point will not change as a percentage of wing cord or away from scaled plans balance point UNLESS you severely alter the wing profile! In scaling up an FT plan the balance point will be as indicated upon the scaled up plans.

It also does not change if you build it out of balsa, Plywood, XPS foam or any other possible material as the balance point is a result of the lift generated by the air moving around the object so its material is irrelevant.

The only thing that really changes is that as you increase the size the wings actually become more efficient.

Have fun!
 

Merv

Site Moderator
Staff member
I'm trying to upscale the Ft alpha is that considered a wing?
If you take your plans and enlarge them, the CG mark will be in the correct place on the enlarged plans.

The FT Alpha has a wing, but I do not consider them a flying wing. With Jets, you need to consider all of the flying surfaces, basically an out line of the underside.