The FP.35's might be a bit much. A pair of FP .20-.25's would be sweet. I'm hoping you made a typo... Steve
Nope, no typo guys, it's getting the .35's.
Built as a featherweight I'm sure the .25's would be ok. I just don't feel like there would be much, if any, reserve power under certain conditions. I'd also like to be clear that I'm not second guessing Don's specs here either, I'm just looking at what's in front of me and following my own preferences.
Seeing it in the flesh this P-38 is a pretty good sized airplane. Also, while it's built nicely, in this particular case some of the wood selection is harder (thus heavier) than I would have used. It won't by any means be a total brick, but I'm not counting every gram as I go either, it is what it is. Within reason, I typically build in plenty of strength everywhere too, and my typical finishes are probably just slightly on the heavy side.
Playing with my 700 square inch PBY (and searching for power with it) for a few years taught me some things. The final version of the Catalina is an honest 84 ounces ready to fly. I battled that plane for two full seasons with a pair of Saito .30's, trying every prop, fuel, and RPM combo you can imagine and it just never had enough oomph to be comfortable doing anything but a giant lazy loop. It would never even stay solid over the top of a wingover. I was very close to just chalking it up and hanging it on the wall for good. Finally though, I bit the bullet and swapped the .30's out for a pair of Saito .40's running Master Airscrew 10x7 three bladers and it
instantly turned into a full blown stunt machine. I tried a few other props on it after the swap too but ended up going back to and staying with the original 10x7's. I have never done anything other than set the needle valves since. I think many here would be amazed at how good the airplane actually is in capable hands.
So, this P-38 has about 140 or so less squares than the PBY but it's still nearly identical in overall size and frontal area. Flap, stab, and elevator areas are very close too. My theory here is that the finished flying weight difference between running a pair of .35's instead of .25's will only be about four ounces on what will probably end up being about a 70ish (or more) ounce model RTF. Yeah, it's gonna honk with the .35's, but that's also why they put that screwy thing in the end of the spray bar. Anymore I'm of the philosophy that it's a lot easier to slow these things down than it is to "squeeze the turnip" looking for every ounce of power whenever you're at the field. Operating on that fine line can leave you with a finicky model and take a lot of the fun out of things in my opinion. I'm confident that once the P-38 is all dialed in with the right prop, RPM, and line length combo it will do quite well, plus, it'll sound ten times cooler than a ceiling fan.