This appeared in AeroModeler in '65... it was the only design that my Dad ever used and it's the only one that I've ever used. The one pictured here is 2 1/4" ((from leadout hole to leadout hole)) elevator control bellcrank. It's for a .15 carrier Aichi B7A1 Ryusei ( Grace) that I'm putting together. I've made 3" ((from leadout hole to leadout down to 2")). The 1/2" from throttle pivot to elevator control bellcrack pivot remains constant. It's made from 3/32" T-6 aluminum with 6:32 machine screws.

I'm not smart enough to know if this will result in the thing wanting to pull the throttle open or closed, but it'll be one or the other.

On reflection, the pull on that one line will be weaker -- instead of the pull being apportioned 1/3 1/3 1/3 it'll go 3/8 3/8 1/4.  So it'll act like you're always pulling on that line, and the force will vary with line tension (tra la).

Don't the rules on the line sizes say the pull needs to be equal?

Randy, I have built sold nearly 200 Carrier kits of several sizes over the years using my own BC's. They always worked as you mentioned. Tim, time to relax. Sometimes over engineering isn't worth the trouble. With that said, I would NEVER, NEVER use this type of BC in  a Class 1 or 2 ship! Now, with the advent of popularity growing in the use of 2.4, and the fact that Class 1 or 2 activity is really rather slim, the BC shown by Randy is not necessary either.  IMHO ONLY.
Joe