I bought 2 of these little engines from David at Gas RC Hobby Engines to put on my new Uravitch 81" Bronco. His support and service is great. I had custom mufflers built by Bisson and rotated one of the cylinders/pistons to allow both engines to face in board. I have run the engines on the bench and love the ease of starting and reliability. The airplane is finished and just waiting on better weather to test run and fly.