On Thursday, February 28, 2013 5:27:46 PM UTC-6, wrote:
Look at 14CFR Part 45 sections 21-33 for regs It is very clear that 3" is OK for gliders Part 45.29(b)(ii) Part 45.22(b) seems to limit the antique use of 2" to experimental I used 3" on my last project and did not worry about it.

45.22(b) says if it is small and over 30 years old, it can use 2 inch. The "or" in there is so that you could make a new plane that looks like an old plane and put 2 inch numbers on it. Not limited to just antique experimental.

Yes, Pete. You can use 2 inch high numbers. Google 14CFR, then look at Part 45. It will tell you all you ever wanted to know and then some. The only thing magical about 1981 is that for a short time, they permitted new planes to have 2 inch high numbers on them. And they can stay that way until the plane is re-painted.

Personally, I like the big numbers on the side of my Ka-6. Helps it look more sleek!

Steve