You're thread title says "Struts" but your message says "Spars".

I'm sure that you know that you need a spar to support the wing. I assume your question has to do with struts, like you would see on a Piper Cub, etc.. Most RC planes do not have wing struts unless they are needed for scale realism.

BUT, since this plane is an original design, it is kind of up to the designer to decide.

Good luck.