a new guy just started flying with our flying group. he has one those nitroplanes zlin 50's. we were all admiring it because it is a very nice looking plane. but he told us that he was very disappointed with the covering thats on it. he said it was not a known covering and it is not very durable and it wrinkles and sags easily and the covering is constantly coming loose on it. but it is a great flyer. he was doing some really good 3-d flying with it. he had a large 4-stroke on his but i do not know what size engine it was. i hope this does not burst your bubble about getting one.