Answered: Expanding catapult

As I understand rule sg10, it’s legal to have a catapult that expands outside of 18"^3 (not upward) while within the climbing zone at any time during the match. The catapult would start within a 18"^3 and retract back within that size when outside of the climbing zone (it would never be used outside of the climbing zone because it would only be manually loaded).
Is that true?

Yes, this is legal.