Of relatively advanced concept and the first fighter to be built by the Arado Handelsgesellschaft of Warnemunde, the SD I was designed by Ing Walter Rethel and owed much to experience gained with Fokker. Of comparatively small overall dimensions, the SD I was a single-seat sesquiplane of mixed construction. The fuselage was of welded steel tubing with light alloy skinning to the cockpit firewall and fabric aft. The wings were wooden with plywood skinning, featuring ailerons in the upper wing only, the cellule having V-type interplane struts and lacking conventional flying wires. The SD I was powered by a  nine-cylinder Bristol Jupiter air-cooled radial and armament comprised two synchronised 7.9mm 08/15 machine guns. The first fighter design to be the subject of a contract from the Reichswehrministerium, the SD I was built clandestinely, flying on 11 October 1927. Evaluation revealed poor low-speed handling characteristics, and, as it was considered to be structurally unsound by the RWM, its development was discontinued in favour of an entirely new design, the SD.II.
Type Single seat fighter
Engine 1 Bristol  Jupiter VI
Dimensions Length 6.75 m, height 2.90  m, span 8.40 m, wingarea 16.8 m2
Weights Empty 850 kg, flying weight 1230 kg, wing loading 73.2 kg/m2
Performance Max. speed 275 km/h, service ceiling 7000 m, climb to 1000 m 1.6 min.to ยจ7000 m 20,6 min,
Armament Two fixed forward firing MG 08/15 7.92mm machine guns
Type Werk.Nr Registration History
49 Tested at Rechlin. Crashed on the 11th of october 1927 on the 21st flight, pilot Dr. Theodor Bienen was killed