Master Airscrew and APC props are both versions of glass filled nylon. Basically nylon with bulk glass fibre in it for reinforcement. Common material for many mid-high strenght plastic apps.

With smaller engines, I always use a nylon prop, the small engines are inexpensive to repair, and actually I've not damaged one yet due to propstrikes. On gassers and other larger engines, wood seems a safer bet for the engine.

Wood props are lighter and really help the gassers accellerate much better. I've got a few 18x8 props. The wooden zinger weighs about 90g. The MAS weighs almost 150. Engine throttle response is markedly different between the 2 (G-38).

J