The Quintus and the Lange Antares 23E were developed in a joint venture between Lange Aviation GmbH and Schempp-Hirth. The two companies have agreed to coordinate marketing. The 18m inner section of the wing was developed by Lange with the assistance Professor Loek Boermans of the Delft University of Technology. The outer section have Maughmer winglets. The wings' moulds have also been used for the Lange Antares H3 experimental fuel-cell aircraft. The biggest differences between Antares 23 E and Quintus are the fuselages and the propulsion units. Lange Aviation have installed an electric system whereas the Quintus has a SOLO 2625-02i combustion engine.
At 58 kg/m2 the Quintus has a wing-loading 20% higher than its predecessors and its high aspect ratio will give good climb rates in thermals. It will only be available as a self-launcher with a steerable tailwheel.