Because there was no proper training aircraft in the post-war period, Jean Stampe decided to build his own.
Another ex-war pilot, Maurice Boel, brought him, during a reunion, in contact with the Brussels engineer Alfred Renard. They immediately clicked with each other and a little later they started their first project.
Renard's designs had the type designation RSV (Renard-Stampe-Vertongen). Their first realization was the RSV 32-90 which was built under the most primitive circumstances in the cellar under a dancehall in Evere.
As registration was chosen after the Belgian designation "O-", the letters "BOEL" as homage to the comrade who brought them together (after 1929 "O-BOEL" became "OO-OEL"). In total 57 RSV 32-90 were built before production was stopped in 1932. This was the first Belgian aircraft to do service in the Military Airforce.
The search for a suitable location for the flying school brought Stampe to Antwerp where he found the grounds of the new airfield and in October 1923 the school started.
In 1927 the company Stampe became the representative for the Havillands and sold for them the very successful "D.H.60" Moth in Belgium. In Paris he had spoken to the Russian aircraft engineer George Ivanow and who with a number of countrymen came to work for Stampe.
He put his first design on the drawing board, the SV.1, which was redesigned with the necessary improvement as the SV.2. The third version, the SV.3, was built and registered as "OO-JYM". Not happy ,with the first delivered product, Ivanow went back to the drawing board and came in 1933 with the SV.4, a somewhat reduced version of the SV.3.
However the aircraft market was taking place primarily with the military. The military had the requirement and, more important, they had money. And thus the SV.5 came off the drawing board. It was a multi- purpose machine for fighting and reconnaissance. The machine was a success and the Belgian Air Force ordered 20 of them.
In the meantime Stampe did not rest on his laurels. Together with Ivanow he investigated the plans of a bomber for the Belgian Airforce. Ivanow started to design, calculate and draw. The SV.10 did its test-flight on 4 October 1935 with Stampe's son, Leon, at the controls and Ivanow as passenger. The following day they took-off for the second test-flight. Over Borsbeek things went very wrong, the SV.10 went into a spin from low altitude and crashed. Both crew were killed instantly.
One of the colleagues of Ivanow, Demidoff, succeeded him as chief engineer. He adapted the SV.4, which was not suitable for aerobatics, for a new client, Mrs. Leysen. He redesigned the top-wing such that the passenger would not have to do aerobatic exercises to get into the front cockpit. With the following machines also the bottom wings were redesigned and the renewed aircraft was now designated SV.4B.
Because of a little dirt on a figure with the copying of the drawing which, by the carpenter was seen as a comma, the wing adjustments were made 10mm smaller and to the utter amaze-ment of Stampe the somewhat stiff SV.4B became suddenly a willing and forgiving dame in the air. It was a dream machine and everyone who flew on it, fell in love with it.
The production of the new aircraft was started and the Belgian Air Force ordered twenty of them. Delivery started in the summer of 1939. Also with civilian pilots the SV.4B became a real success. On 1 September 1939 the war broke out and France and England went to war with Germany. Stampe was faced with the problem that Belgium was neutral and he was given orders by the French.