Maybe it's me but I've always run 10X7 or even 11X7s on my LAs. 10s for the .40 and 11 for the .46. Ilike these engines because they're light. That means Ican put them in smaller airframes and pull the plane around with a 10 inch prop where the designed ball-bearinged engine would only spin a 9X6 or something like that. I'm thinking like the Great Planes .25 T-craft or the Thunder Tigre Lazy Tiger Mustang that Icurrently have a .46LA on the front. It spins a 10X7 4-blade APC prop quite well. Ilove these little "underpowered" engines!