This may seem like a dumb question to some however, seeing how I have never done this before I thought I would ask. I currently have lots of plans in the 60-90 2-cycle size. I just bought a new Desert Aircraft 50. What I would like to do is to increase the size of these plans to be suitable for my new 50. For example, I have plans for a Kaos 90. What is the mathematical formula to come up with the correct percentage to blow up the plans to fit the 50. Would this formula work on any size plane as long as you know what the displacement of the current plan is and what you want to go to? Any help would be greatly be appreciated. Thanks in advance...

Spencer