Sweden had fallen behind the rapid technical progress being made elsewhere, and
Saab needed to catch up in terms of
aerodynamics and jet propulsion. Accordingly, project "JxR" was initiated in late 1945 and requirements were drawn up in October 1945. A pair of proposals were presented by the Saab design team, led by
Lars Brising. The first of these, codenamed
R 101, nicknamed ("the cigar") due to its shape, bore a strong resemblance to the American
Lockheed P-80 Shooting Star. The second design, which was chosen, was the
barrel-shaped design, codenamed
R 1001, which proved to be both faster and more agile. The nickname "the barrel" evolved early from this design, but for a while it also had the nickname ("
One Thousand and One Nights") after the project number 1001. The R 1001 concept had a straight wing, but after the engineers obtained German swept wing research data, it was given a 25 degree sweep. Information on swept wings came through Switzerland and included drawings for the
Messerschmitt P.1101,
P.1110,
P.1111 and
P.1112. SAAB's project manager,
Frid Wänström, collected these documents in 1945 from Messerschmitt engineers who escaped to Switzerland at the end of the War. Among them was engineer and aerodynamicist
Hermann Behrbohm, who joined Saab's J 29 team. These documents clearly indicated delta and swept-wing designs "reduc[e] drag dramatically as the aircraft approached the sound barrier." To make the wing as thin as possible, the
undercarriage retracted into the fuselage, rather than the wings. These tests determined the required fuselage form to ensure it could attain the targeted critical
Mach number, as well as supporting the use of a straight-through airflow to maximize thrust. Automatically locking
leading edge slots, interconnected with the
flaps, were also deemed necessary for lateral stability during take-off and landing. To further verify the swept wing, a
Saab Safir was modified with a full-scale wing as the
Saab 201. The original powerplant was to have been the
de Havilland Goblin turbojet, however, in December 1945, the more powerful
de Havilland Ghost became available. This was ideal as not only was the Ghost set up for a circular air intake, its diameter would fit within the planned fuselage. Despite early doubts for the supply of an equivalent to the American 75S aluminium
alloy, Svenska Metallverken was able to manufacture it, although significantly larger sections were used than typical for aircraft construction. The structure employed heavy frames and stressed skin to meet conflicting requirements on space, strength, rigidity and accessibility. However, these modifications delayed the first flight until after the hoped for date of 1 August 1948. who was later the first managing director of
Saab GB, UK. Following the flight, Moore described the aircraft as "on the ground an ugly duckling – in the air, a swift." Because of the shape of its fuselage, the Saab J 29 quickly received the nickname
Flygande Tunnan ("The Flying Barrel"), or
Tunnan ("The Barrel") for short. While not appreciated by SAAB, its short form was eventually adopted officially. Four prototypes were built for the test program. The first two lacked armament, carrying heavy test equipment in their place instead. The third was armed with four cannons. Between 1950 and 1956, 661 Tunnans were completed, the largest production run for any Saab aircraft. == Design ==