I flew mine with a Thunder tiger pro 46 2 stroke, it had all the power the Decathlon needs. I used a 12x5 APC prop. A four stroke would be more in keeping with this style of aircraft, but is in no way a 'must have'. Once you get the ground handling nailed, you'll love it. The secret to the decatlon is applying power smoothly and progressively on the take off. Any sharp power applications will have it ground looping. Be ultra careful with crosswind take-offs, dont attempt them until you have really mastered the 'into wind' take-offs.