{"id":13431,"date":"2009-12-01T18:57:21","date_gmt":"2009-12-01T17:57:21","guid":{"rendered":"https:\/\/www.dg-flugzeugbau.de\/en\/?page_id=13431"},"modified":"2023-03-28T11:39:37","modified_gmt":"2023-03-28T09:39:37","slug":"the-roeger-hook","status":"publish","type":"page","link":"https:\/\/www.dg-aviation.de\/en\/library\/the-roeger-hook","title":{"rendered":"The Roeger Hook and DG\/LS Sailplanes"},"content":{"rendered":"

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Almost all sailplane pilots wear parachutes when flying. Naturally, we do not expect to ever use them, but we don’t want to take unnecessary risks. But in an emergency the parachute is only useful if the pilot can leave the cockpit of a probably uncontrollable sailplane. But that is often a problem.<\/p>\n

We have reported extensively on the NOAH system, but just like a rocket assist, it presumes that the canopy has first been ejected. But there are two known situations when that is not possible. Sometimes the canopy moves back a bit in an emergency ejection and then gets pushed down in the airstreams to such an extent that the pilot has great difficulty to shove it out of the way. That uses up valuable time. Even worse, the departing canopy can hit the pilot on the head and causes him to lose consciousness.<\/p>\n

To avoid these situations Prof. Roeger of the Aachen University of Applied Sciences many years ago invented a special hook, since named for him. After the emergency release the hook turns on the rear canopy frame and prevents it from moving back. The airstreams flowing into the cockpit cannot escape and therefore lifts the canopy, which rotates on the Roeger hook and forces the front of the canopy to lift off and depart rearwards over the tail fin. Such a Roeger hook has been a mandatory installation in all new sailplanes for some years. Great, problem solved.<\/p>\n

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But there are still several thousand older sailplanes without a Roeger hook. In the spring of 99 a pilot in the US died after a mid-air and pulling the canopy emergency release, but remained seated in the cockpit without even undoing his seat harness. Analysis of his head wounds showed that he had been knocked unconscious by the left side of the canopy frame.<\/p>\n

We have decided to find a solution to this problem which could be retrofitted to older sailplanes and perform the function of a Roeger hook. The hook itself can only be retrofitted at considerable expense, but a small spring loaded pin can accomplish the same purpose by fixing the canopy in the rear position until the slipstream lifts the front of the canopy over the pilot. For that we need a strength of about 8 KG according to the experiements of Prof. Roeger.<\/p>\n

We offer this solution to all pilots and sailplanes of the series DG-100, DG-200, DG-300, DG-400 and DG-600 as well as LS4 to LS8 which do not have a Roeger hook as a retrofittable substitute. A Technical Note for LS1 and LS3 is under construction.<\/p>\n\n\n\n\n\n
Technical Dra<\/a>wing-1<\/a><\/td>\nTechnical Drawing 2<\/a><\/td>\n<\/tr>\n
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\"roegerhaken1\"<\/a><\/p>\n

 <\/p>\n<\/td>\n

\"roegerhaken2\"<\/a><\/td>\n<\/tr>\n
\"roegerhaken2\"<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Dear pilots of the above mentioned DG and LS single seaters:<\/h4>\n

None of you should fly next season
without this safety improvement in his sailplane.<\/p>\n

Technical bulletin # 301-21 for DG gliders can be downloaded<\/p>\n

 <\/p>\n

Retrofitting of Roeger hook and canopy lift spring for older versions of LS gliders<\/h2>\n

An explanation by Wilhelm Dirks<\/h5>\n

It is well established, that Prof. Roeger at the University of Aachen, did quite a lot of tests with a LS fuselage in order to examine the canopy drop during flight. The deflating results of those tests can be read in a project report.<\/p>\n

The test program showed that the canopies did not fall apart the fuselage due to aerodynamic reasons or even hit the pilot during the drop causing heavy injuries. As a result of these tests, the well-known \u201cRoeger-Hook\u201d was developed. But furthermore the canopy had to be lifted upwards in the front by the pilot. This issue then was solved by combining the Roeger hook with a lift up spring enabling a safe drop of the canopy.<\/p>\n

These requirements, of cause, were then included in the building code for sailplanes and motor gliders (JAR22, CS22).<\/p>\n

Rolladen Schneider immediately modified their state of the art sailplanes but unfortunately didn\u2019t carry out a solution to retrofit older LS types.<\/p>\n

DG was informed about this problem by multiple experts. As a result we developed the Technical Note for old LS gliders. Even the judicial side is enough to force us developing a solution. Think about claims for compensation because a bail-out was not possible and DG knows about this problem all the time.<\/p>\n

A lot of pilots ask us:
\u201cDo we need to adhere to the Technical Note for LS canopies?<\/p>\n

EASA Part M clearly states out that maintenance has to be done strictly according to the type certificate holder\u2019s documentation. So all actions declared as mandatory in the Technical Note have to be carried out.<\/p>\n

Part M regularizes all matters dealing with maintenance and inspections for non-commercial aircraft below 5.7 tons.<\/p>\n

M.A.401 a) regularizes that maintenance has to be carried out by the latest maintenance documentation (including Technical Notes) and M.A.401 c) regularizes that all personnel or maintenance companies doing maintenance on the glider have to ensure that maintenance documentation is at the latest standard.<\/p>\n

Regarding the inspection of airworthiness, M.A.710 a) 10. states out that it has to be checked that the aircraft is equipped according to the latest standard approved by EASA.<\/p>\n

Judicial position for inspectors:
The airworthiness inspector has to check the current situation of Technical Notes and Airworthiness Directives for the aircraft he inspects and if all binding actions have been done before he is allowed to sign a new ARC.<\/p>\n

In case the deadline for binding actions has passed and an ARC is handed out anyway, the inspector commits an administrative offense. Also, in case of a crash he can be prosecuted in case the ignored actions might have changed the crash\u2019s results.<\/p>\n

The new and re-worked Technical Notes (Canopy-Ejection) for LS-gliders you find below:<\/p>\n

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