The unit 3 (short: A3 rocket) was a German test rocket , with the help of which important components for the planned unit 4 were to be tested. She was 6.74 meters long, had a diameter of 0.68 meters and had a takeoff weight of 900 kilograms. Its engine , which was operated with alcohol and liquid oxygen conveyed by compressed gas , developed a thrust of 15 kN .
On December 4th, 6th, 8th and 11th 1937 take-off attempts were made with the A3 on the Greifswalder Oie , all of which failed because the shape used did not permit stable flight.
Since a model for testing various components was required for the development of the A4 rocket, another test rocket with the same engine was developed with the unit 5 .