I have a couple Guillow's 400 series P-40 Warhawks (the larger 27 3/4" wing span) and I plan on building it just for fun, but if it turns out to being able to stunt, then for me, it will be two checkmarks in the "Win" column! Of course, we all know the plans include instructions on converting these to Control Line. With the venerable Cox .049. But how far have you taken one? Or one similar? I have an MP Yellowjacket .15 rear exhaust and a matched tuned pipe. I am about to get started on it, first, I will make an engine crutch, figure out the placement of the pipe and controls. But I'm obviously not planning on flying it in any competitive event, this strictly for fun.
What do you say? Have any of you built a Guillow's kit to fly CL?
Back in the early 80s when I was like 13 or so, I received a Guillow's P-39 kit. Excited, I spent all summer building it (with one corroded razor blade, and God-only-knows for glue!) and I elected to build it for C/L, using the Cox .049 that once resided in my Cox PT-19 and it's plastic handle (complete with Dacron lines). The grass was way too thick at my parent's place for a proper take-off, so I had my sister hand-launch it for me (keep in mind, that starting that engine took a lot of effort, wasted Cox fuel, 1.5v batteries and Cox glow plugs to even get it running....

). But, once it was up and running, I gave her the signal and she released it.
Full disclosure: this is where I learned all about planes with way too much aft C/G - the plane shot almost straight up (for like, 10 feet or so), and despite giving it all the down handle I could give it, the inevitable stall took place, crashing tail-first - ruining an entire summer's worth of effort. I was quite upset about it then, but chuckle about it now!
Definitely not a beginner's plane - even when "graduating" from a Cox PT-19. I eventually went with a Carl Goldberg Lil' Wizard and had way better success with that. But, even as an inexperienced 13 year-old builder and flyer - I discovered that flying those Guillow's models in C/L form can be done (even if it did a 1/4 lap!). If I had to do it all over again, I would have built it stronger in the nose. And lighter. And would have found a way to purchase better glue and fresh razor blades. And probably would have used something better than that base-model Cox .049. And paid better attention to things like CG.
Even so, as some had already suggested, it had a flat-bottom wing, so stunting it might not be possible. But, those were good times back in the day!
Good luck with yours!