You're half correct. It has to be built exactly per manufacturer specs. However, once it has been certified, you can modify it anyway you want.
This is correct, from the
original link [
vansaircraft.com] I posted, here is what Van's say:
How can an RV-12 be licensed?
The RV-12 is designed to be licensed as an Experimental Light Sport Aircraft (E-LSA). Currently RV-12s in the USA have been licensed in both E-LSA and Experimental Amateur-Built (E-AB) categories.
Although the E-LSA category does not permit builders to deviate from the kit or plans (no unapproved engines, propellers, etc. are allowed) it does have some very attractive features. In the E-LSA category, there is no "51%" rule, and no restriction on who may assist in building the airplane. This allows any amount of help, professional assistance or even a fully professional-built airplane.
The only way there can be a RV-12 S-LSA is if Van's starts building and selling the plane itself. I believe the prototype RV-12 built by Vans is a S-LSA. The RV-12 has some impressive specs. A useful load of 580 pounds (420 lbs with full tanks), top speed of 135 mph (120 knots), and a fuel burn of around 4.5 gph.
It is bigger inside than a 150 and flys faster, all on less fuel. It does cost a little more than a 150, but with some sweat equity, you can have something comparable to a $120,000 LSA for half the price.
