Steel guitar strings can be pretty handy items. For instance:

Four stroke flyiers can attest to carbs being located in difficult to get to positions. A wound "E" string is far more fexible than the standard RC control cable and will make throttle control connections easier. In situations where the carb control arm is located close to the firewall to accomodate a clevis, strings can be "Z"bent to connect to the throttle arm. No clevis needed. For extra stiffening, saturate the string with solder. Phosphor bronze coated strings love solder. Just flux and it wicks like crazy. The outer sleeve may be typical Ny-rod or similar tubing. I've been using this method for some years now and have no complaints.

Guitar strings ought to lend themselves well to other uses. Haven't had a need, but an "E" or "B" string ought to be perfect as spoiler actuator cables. Brace wires ought to be another natural. Flying wires that do not actually carry load can be fashioned with 2-56 clevises by wrapping a "B" string for a 3/4" (or so) length. Soak with solder then thread on a clevis.

BTW, the eyelet swedged on the end of strings makes them just right for pulling electrical wires.

Now for the nuts and bolts:

E* string=.013 dia, rated 27 lbs pull
B string= .017 dia, rated 26 lbs pull
G string= .026 dia, rated 35 lbs pull
D string= .035 dia, rated 36.8 lbs pull
A string= .045 dia, rated 34 lbs pull
E string = .056 dia, rated 29 lbs pull ( this string is wound and is most useful as throttle control cable.

* Note: guitar strings have two "E" strings. The "E" string mentioned in the narrative refers to the "Low E" or "wound" string.

Guitar strings are often sold by individual strings as well as in complete packs. If you pick guitar or have a friend who does, you'll have a ready supply of free strings! If not, you need only buy the specific size that suits your needs. Good luck!