ORIGINAL: rainedav
So, I take it scaling is not legal in SPA? Now that would open the door to a lot of different designs being built, I'd bet. Any design from the era could be enlarged to suit the .60s and .91s of today. IMO, scaling does not change the character of a design too much as long as the proportions are kept original.
Correct--scaling is not allowed. The thinking behind this has to do with what is called the "Duck Rule" which says "...if it looks like a duck, it's a duck..."
Yes, if a Kaos was scaled up, it would still look like a Kaos--but a REALLY BIG Kaos. Everyone knows what a Kaos is supposed to look like, how big it's supposed to be etc. If someone showed up with a huge Kaos it would stick out like a sore thumb. Many SPA planes have small mods compared to the original to help them fly the current SPA pattern, (somewhat different than the one in effect in the 60s when the Kaos was state of the art), better, and better accept the heavier 4-stroke engines. Fuses are lengthened slightly for balance purposes, strip ailerons may be replaced by barn-door, maybe the rudder hinge line may be made to be vertical for Knife-edge flight etc., but the general look and size of the original is preserved. A 2-meter size Kaos would not fly like the real thing--and wouldn't pass the "Duck Rule".