Bennett Brothers "The smoke pump" guys still sell the 38cc model for $150.00. I have had the chance to run one before and it was strong. It does however weigh in at about 5lbs. I suppose that wouldn't hurt if you picked the proper plane for the engine. I can not remember the numbers it turned off the top of my head but they were slightly better than a new US41 being tested at the same time with the same props. Both engines were new.