Prop choice, gas airboat.
I built an airboat a few years ago, but I got tired of the whole project so I put it away for five years or so. The boat is 58"x23" and weighs in at 16-17lbs. I converted a Ryobi 31cc engine, that I have modified for more power. I´m more into gas boating, so I havent got a clue about air propeller, this is where I need some help. I just brushed the dust of the boat and would like to get it finished, at last. I testran the engine on a bench yesterday, and it ran 8600 with a MAS classic 18x8 (only prop LHS had in this size), pulled my heavy workbench over the floor, scared the crap out of me, never expected that. Any idea what kind of thrust this setup is delivering? I have been told that the Ryobi should stay below 7500 because of the week conrod and crank, so I guess I have to get a bigger prop. 18 is the biggest prop that I could use, so I guess it have to be an 18x10., or any other suggestions, or other prop brands recommended? Do airboats need a high pitch prop, or do they like more thrust? What kind of speeds are you seeing from airboats of this size and power ratio?