My friend Rob has been teaching me about formation flying. We like to do ovals around the pattern at full throttle with a few basic maneuvers tossed in while trying to fly next to each other. We knew the risks. Today we made contact. I got off easy with a chewed up prop. Rob’s Seagull 20cc Yak 3U Steadfast took the brunt of a DLE 35RA swinging an 18x10 prop. We both landed safely. It’s amazing that Rob was able to bring the badly damaged Yak in for a nice landing. Half of the Yak’s elevator was ripped off and the rudder and vertical stabilizer were badly shredded! He’s an excellent pilot.