The Roeger hook, and it's variations, enable a clean jettisoning of the canopy. The hook holds the rear of the canopy to fuselage until the front of the canopy has lifted high enough for the air flow to lift it off the glider. Without this hook, the canopy may "jump" backwards, hit the pilot and injure him, or impede and slow his escape.

Here's an article on the DG site, including videos of some of the testing done by Prof. Roeger. Scroll down half-way for the research project report.

Newer ASH 26 Es are delivered with a Roeger Hook already installed.If you have an older ASH 26 E, please install a Roeger hook for your safety!Schleicher has a kit for this, and the labor wasn't too expensive when I had mine installed in 1998. The picture shows the plunger installed on the canopy, and catch spring installed in the fuselage.