| Simon,
Sorry to disappoint you, but prop selection is a minefield, everything interacts with each other, motor size, power output, pitch of the prop, type of prop.
I always went for the size shown on the plan and either stayed at that or went smaller with a coarser pitch on. The model steering characteristics also changes, depending on the rotation of the props, whether both going inwards or outwards when viewed from the rear. There is a general concensus about which ways props should run, but to me the way to do it is suck it and see, one way will most probably give better handling, whilst the other might give more power but less steerage.
Sorry I can't be any more helpful than that.
The reason my boat will not be built is that I can't handle them any more, a bit heavy. I am just clearing out all my model boat stuff at the moment.
John |