how long should the boom on a boomstick plane be compared to its wingspan?

do you mean a boom like that on a KC-135? i dont think it really matters.

Or do you mean the noise they make when impacting the ground?

Please explain. What is a "boomstick plane"?

If you mean a "pod and boom" type construction, then the answer is "it depends". I know, not very useful, but can you give more information about what you are looking for? With out a more specific description of what you are doing, it's not easy to tell.

Seeing as how we're talking about a broomstick for a fuselage and this low tech approach is just that, low tech, I would look at the wingspan to length ratio for a bunch of similar looking planes from a few manufacturers on the web and use an average of that.

Shorter fuselage to wingspan ratio will yield higher to unmanageable pitch responses, depending on how radical you get and longer will result in dampened to sluggish pitch response.

BTW, your instrests would be better served by posting your question in the Aerodynamics section.

Good Luck!!

Howabout the same length as the wingspan? yeah, that sounds good