ASW 24 E stalls in downwind after engine trouble on self-launch

After a self-launch from Bremgarten, the pilot of an experimental ASW 24 E was fatally injured and the glider destroyed by post-impact fire. Witnesses heard the engine running roughly from the takeoff roll. The glider gained only marginal height entering right downwind for RWY 05, where it was pulled into a steep nose-up attitude, stalled, dropped nose-down and impacted the grounds of a biogas plant south of the airfield. The glider was a Spanish-registered Experimental rebuilt with a non-aviation Aixro Wankel engine and held no valid airworthiness certificate.

1. Self-launch takeoff: At 12:03 LT the ASW 24 E self-launched from Bremgarten (EDTG) RWY 05 on a private VFR flight, with the engine extended for the launch.
2. Experimental, no airworthiness cert: The glider had been rebuilt from a wreck with a non-aviation Wankel engine replacing the original, modified without consulting the manufacturer, and held no valid airworthiness certificate.
3. Engine runs roughly from takeoff roll: From the start of the takeoff roll, witnesses heard the engine running roughly and stuttering.
4. Only marginal climb performance: The airfield manager observed only marginal height gain on departure as the glider turned into right downwind for RWY 05.
5. Steep pull-up in downwind: Another aircraft's crew and witnesses on the ground observed the glider being pulled into a steep nose-up attitude in the right downwind.
6. Stall and nose drop: Following the pull-up the glider abruptly dropped away (kippte ab) and descended with a steep nose-down attitude toward the ground.
7. Crash - fatal: The aircraft impacted a biogas plant near Bremgarten and the wreckage caught fire, igniting stored material; the pilot was fatally injured and the aircraft destroyed.