I have over 2000 hours flying ag cats on rowcrop here in North Dakota. There was ever only one model of ag cat that came with a wright whirlwind and that was the C model. It never made it to mass production and there aren't any working right now. Ag Cat's haven't been produced since 1990 and was produced mostly with Pratt & Whitney R-985's or R-1340's. When they began production back in the 50's they had 300 H.P. Jacobson radials and were nicknamed "shakey Jakes". They're still a good workhorse in the ag industry and are known for they're good turning ability and short field operation. They also do a good job of keeping the pilot alive when you ball one up. I usually pull it off around 60-65 loaded and got it up to 80 before I try any kind of maneuvering. At that speed....loading the wing up makes for some shakey turns. Loaded light...you can see below 50 at the top of a turn. Working speed down the field is between 105-110mph in the raidal versions. There's a few companies out there now refurbishing Ag Cat frames and converting them to Garret and Walter Turbines. They raise the top wing...extend both wings...drip in a 450 gallon hopper...and put taller gear on it. It's an incredible machine. Check out Skytractor.com And the oil...yeah, they leak. But hopefully not when they're running. When they're sitting...depending on how the valved on the bottom cylinder came to rest...oil can flow out and into the exhaust and make a nasty puddle on the ground. They really are incredible workhorse airplanes!