RE: Help Desk
roltech,
You need two struts right?
There is a very simple way to find the right length for them. You need the measurement from the hole in the bottom "horn" to the top "horn". It will be the same for both sides, but your cabanes are holding the wings so that they're not parallel so the way the plane sits in your enclosed photo, you get different measurements when you measure for the right interplane versus the left interplane.
OK, you've actually got another slight problem. Your cabane struts aren't holding the wings parallel, but my suggestions are going to help solve that while we're working out your measurement.
With the airplane rigged like it is in the picture, take some scrap anything and cut it to fit where you want one of the interplanes to go. Take a pen or pencil and stick it through the attachment holes top and bottom, as if you were trying to mark where to drill attachment holes in that interplane strut. Now take that scrap over to the other side and mark those holes. The bottom marks should overwrite each other and the top marks should be one above the other. Halfway between those top two marks is where you'd drill the top holes if you ignored the fact that your cabane struts aren't "square".
You need to sand down one of your cabane saddles (the "tall" one) so that the two wings are parallel. You need to do that first. The plan I just suggested to you for measuring to find the average distance for the interplane struts will help you when you're sanding down the tall cabane saddle.
Once you get the cabane struts equal, use some more scrap and verify the distances for the interplane struts. They should be equal now.
You've got a sharp looking biplane there. It oughta be fun to fly.