If your flying area has a noise issue, be aware that none of the gas engines will meet the AMA standard without a cannister (not pitts) muffler, and a cannister muffler will not fit in the Patty without major modifications.

If you want to go gas, by all means do so, but don't try to justify it with fuel cost. The difference is about $1 per flight. (Used to be $1.25, but gas prices went up.) Moki 2.10 with bisson pitts muffler is $350. DA 50 with tuned cannister muffler and ignition battery is $750. How long will it take you to put 400 flights on it, just to break even?

Jim