The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) uses the powerful four-seater DR 400/200R Remorqueur - D-EDVE aircraft primarily as a glider tug. In addition, it is used as a transport aircraft and for pilot training. The single-engine DR 400/200R aircraft is based on a Jodel Robin DR 400 made by the French Apex Group. DR 400 aircraft have a characteristic cranked wing configuration which ensures enhanced inherent stability.
Modifications
The following modifications differentiate the DR 400 from the standard Jodel Robin DR 400:
Empty tubes for temporary installation of cables and leads
Hardpoints on the wings and in the cabin for attaching measurement equipment
The DR 400 is used for 'comparison flight procedures': the flight performance parameters of the glider under study are compared – in flight – with a calibration aircraft (for example DLR's DG 300). Until a few years ago, this comparison was made using a photographic method. The two aircraft fly alongside one another at a constant speed for a period of approximately two to three minutes. The altitude difference between the two aircraft is photographed from the DR 400 at the start and end of the flight period. In this way, the change in altitude difference can be determined on the basis of the photographs, using an extremely complex and time-consuming geometric evaluation. This in turn allows a speed polar to be calculated. The measurement principle remains the same to this day, only now the photographic method has been replaced by a GPS-aided measurement. This increases accuracy and reduces the time and effort needed for the evaluation, with the result that the DR 400 is now no longer required as a photography aircraft, and is only used as a glider tug.
Missions – Research focus
DLR uses the DR 400 aircraft principally for measuring the flight performance parameters of gliders.
