/diy/ - Do It Yourself

Reposting to see if I can get an answer this time... Im working on a Guillows kit 402 p51 mustang, 32" wingspan I believe, and I want to run it off nitro. I've done some more research and I believe I'll be going with the O.S. 15LA, but I want some more insight from experienced builders. About a .15 size is probably the biggest I can fit, but if there are other recommendations maybe something .2X sized could work?

Also, the frame is spec'ed for a .049 Cox, so would pushing a .15 (3X the displacement) be too harsh on the frame?

Last question, this involves more theory, the P51 used a duct to cool its radiator and compress the heated air into thrust, I would like to incorporate a system like this that uses the exhaust to heat air that enters the bottom duct, Ill probably make a duct similar to the real P51 for this, along with a small trap door in the back. Would I run into any issues doing this? Most rc planes direct the exhaust away from the fuselage as quickly as they can, would this cause unwanted temp issues?
Thanks for the help!

PS could also use some cool livery ideas

>>1419057 here, expanding more on my build. Im working on a Guillows kit 402 p51 mustang, 32" wingspan I believe, and I want to run it off nitro. I've done some more research and I believe I'll be going with the O.S. 15LA, but I want some more insight from experienced builders. About a .15 size is probably the biggest I can fit, but if there are other recommendations maybe something .2X sized could work?

Also, the frame is spec'ed for a .049 Cox, so would pushing a .15 (3X the displacement) be too harsh on the frame?

Last question, this incolves more theory, the P51 used a duct to cool its radiator and compress the heated air into thrust, I would like to incorporate a system like this that uses the exhaust to heat air that enters the bottom duct, Ill probably make a duct similar to the real P51 for this, along with a small trap door in the back. Would I run into any issues doing this? Most rc planes direct the exhaust away from the fuselage as quickly as they can, would this cause unwanted temp issues?
Thanks for the help!

PS could also use some cool livery ideas