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Chuck Dunlop's Engine Failure

In July, 2003, Chuck Dunlop (AZ) was flying his rotary powered RV-6 to the Arlington Fly In. He was at 12,000 ft over the Grand Canyon when he suddenly heard a BANG and the engine lost most of its power. It was still running, but maximum rpm was only 3900, not quite enough to maintain altitude. Chuck kept his cool and managed to make an emergency landing on a highway with only minor damage to the plane and no injury.

At this point you may be asking yourself "Hey- Didn't Tracy Crook say the rotary had no failure modes when operated under 6500 rpm?" Well, yes he did, as long as the engine is fed fuel, and the liquids are kept at the right temperature. To that we must add "and doesn't ingest any hard metal objects."

Post incident inspection revealed that one of the rotors had no compression and there appeared to be foreign object damage inside the rotor housing. On closer inspection he found that the secondary port barrel valve was loose in its recess and that the actuating rod had fallen out.

As shown in the Aviator's Guide to Mazda Rotary Conversion, (page 52 of the latest edition) this rod should be removed prior to installation of the barrel valve. Chuck purchased these valves at Pineapple Racing, who had performed the streamlining of the inlet path as shown in the Aviator's Guide, but had not removed the actuating rod. Since the valves remain fixed in aircraft applications, the rod serves no purpose and only impedes the air path to the port.

The rod on the right fell out. Apparently, the barrel valve first backed out of the side housing, then the rod fell down and the barrel valve oscillated back and forth with the impressively strong pressure pulses that exist in intake systems.

Ouch! Here are the final results. You can see where the pin was pinched between the rotor and rotor housing. The apex seal also broke off adding to the destruction.