I have several of these beauties and would like to know in which Control Line model they would work best. What engine are they equivalent to? A Cox .10? An OS .15? I am running them with 7-3 props.
Centurion, I flew and messed around with a couple of these engines way back before dirt, around 1965 +/-. They started easily, ran well but were not a "power-house".
You wish to try one out? Easy!
Get a 3x36" relatively hard balsa, preferably 3/16 or lighter 1/4" balsa. Cut the wing at 24", and save the 12" remaining for the fuselage. Use some light 3/32" balsa for the tail feathers or hard 1/16" sheet will work. Make the stab 20-25% area of the wing. Vertical tail as you wish to suit what you want it to look like, but at least 33% of the horizontal stabilizer total, stab and elevator.
Now a bit of 1/32 or even 1/16 ply for doublers forward of the wing TE. If ( I forget) the Gilbert mounts on rails, the fuselage should be at least 3/16 inch thick with the engine just ahead of the wing LE, either sideways for rail mounts under the ply doubler or a good 3/16" to 1/4" ply firewall if radial mounted. A easy tank is a couple balloons tied around a fuel line with a tube inside where you tie it off. Fill with good hand bulb or a syringe found at any animal feed store.
Don't forget a 1/8" ply for the bellcrank usually mounted next to fuse. under the wing.
With some imagination one can build a very nice CL profile or even built up fuse. model for these small engines. Don't forget some 1/16 music wire to fashion gear legs with also mounted at LE of he wing. CG should be 3/4" behind LE of 3" wing.
I can build such as this in some 1 hour or less, no plans needed. Then another couple hours to add a couple coats of dope with some talcom powder mixed, let dry 30 minutes or so, and then sand it down a bit. Brush on a couple coats of color and it will be ready to fly soon. Actually dope needs some time to cure or glow fuel can cause some milky addition to the finish. Have some to prove that when a couple nephews wanted to fly it "YESTERDAY".
I keep a few with 1/2 to .19 engines ready for any kid wishing to give it a try in my back yard, up to 65' lines, and up to 40 engines. One is a profile, solid wing, with Fox .19 which is over 16 years old. Has a lot of scars, but solid flier.
Go test those Gilberts. They can provide some real fun.