Originally Posted by
combatpigg
The G2 5.5 x 5.5 prop is a good one to try.
I remember having a great time with this kit and with the plane that came out of it.
The F2A speed trainer article you can find through NASS mentions that best speeds on that model were with around a 5.5 x 5 with some blade area:
- Propeller. The best speed was achieved with a Master Airscrew 7x5 S-2 G/F Nylon Gray Propeller cut to 140 mm (5.5 inches) diameter. With this prop the engine was turning about 30,000 rpm in the air. I suggest starting with 6 inch diameter and cutting the prop until the engine pipes up. Too small propeller will turn a lot of rpm with no thrust. We also tried more pitch (up to 6.5 inches) but this did not result in faster speed.
- With these modifications and settings the system performed quite well. The fastest time achieved in a practice session was just over 200 kph, which is excellent considering the exposed lines, landing gear and no engine cowling. The airplane routinely did around 160-180 kph with a Rossi pipe and slowed down to 150 kph on the stock pipe (on FAI 80/20 fuel).
Even though this is just a sport 1/2A model by design, with no lines there is every possibility it will leave the ukie trainer in the dust. As mentioned ad nauseum, I clocked 126 mph on a Simple 400 - similar wing - with about 300W electric.