The importance of aerodynamics for motor vehicle construction had already been recognised in the 1920s and 1930s. The best-known examples with streamlined bodies include the Rumpler Tropfenwagen and the streamlined racing and record-breaking cars from Mercedes Benz and Auto Union. One of the pioneers and masterminds of this field of research was Baron Reinhard Koenig-Fachsenfeld. In addition to various designs for automobiles, Fachsenfeld had already looked into two-wheeled streamlined vehicles in 1937, but the version designed for DKW was not controllable. The low-seater developed from this experience in 1938, which was considerably lower due to the seated position of the driver, could no longer be realised because of the Second World War.

Wilhelm Herz, who had already been involved in the reconstruction of the 350 cc NSU pre-war compressor engine, succeeded in convincing NSU’s chief engineers of his record plans with Fachsenfeld’s design in 1948. By spring 1949, NSU had

completed the fairing, but the Herz accident in Cologne put the brakes on further work on a suitable unit. Since no other NSU driver wanted to drive the “record cigar” with its reclining chair-like seating position, Dr. Froede informed Fachsenfeld at the end of 1950 that the project was to be discontinued. The time was not yet ripe for Fachsenfeld’s revolutionary concept.

Nevertheless, the record plans were not shelved in Neckarsulm. On 12 April 1951, NSU machines set off on their first post-war speed record runs on the Munich-Ingolstadt motorway. On the Delphin I, a disguised NSU supercharged 500 cc machine, Wilhelm Herz beat the 14-year-old world record (279.5 km/h) set by Ernst Henne on BMW in 1937 by 10.5 km/h. On 25/26 October, Hermann Böhm also set a new absolute record in the sidecar class with 248 km/h. All in all, eight new world speed records were set on NSUs in April and October 1951.

In the same year, the graphic artist Gustav Adolf Baumm contacted NSU for the first time to present the idea for his record-breaking vehicle project, which went far beyond Fachsenfeld’s concept with the driver lying on his back. After he had convinced development manager Dr Froede of the controllability of such a vehicle with a converted ironing board, he could count on material and financial support from NSU. With the successful presentation of his first “Baumm’s recliner”, Baumm received a permanent contract in 1952 and developed the Baumm I and II together with the NSU research department. With this vehicle, an improved 50 cc NSU Quickly two-stroke engine and an optimised 100 cc NSU Fox four-stroke engine, he broke a total of eleven existing world records in 1954 in the classes from 50 cc to 175 cc as designer and driver.

In early May 1955, Baumm again set 22 world speed records with an improved Quickly engine (50 cc) and a Rennfox engine (125 cc). On 29 May, when he finally wanted to demonstrate

the circuit suitability of his vehicles on the Nürburgring, Gustav Adolf Baumm had a fatal accident.

In 1956, NSU goes on the record hunt one last time. The first project was an economy record with a shortened “deckchair” and a 125 cc Superfox engine. H. P. Müller needed an average of only 1.13 l/100 km in the Baumm III on 29 May (for a total distance of over 500 km), while the production Superfox travelling along for comparison swallowed 3.22 l/100 km.

The second project took NSU to the Salt Flats in Bonneville, Utah/USA in July 1956, which offered ideal conditions for the renewed record attempts in terms of ground conditions and wind conditions. H. P. Müller competed with the Baumm II and three different engines (50 cc two-stroke engine with rotary piston compressor, 100 cc and 125 cc Rennfox engine) in the classes from 50 cc to 175 cc. Wilhelm Herz competed with the new Baumm IV and the Delphin III and 3 power units (250 cc

Rennmax engine, 350 cc and 500 cc two-cylinder compressor engine) in the classes from 250 cc to 1,000 cc. With the Baumm II, Müller improved all speed records up to the 175cc class and was even able to claim the records in the 250cc class for himself, as Herz no longer drove the Baumm IV with Rennmax engine after a smooth crash. The top performances were 196 km/h from 50 ccm and 242 km/h from 125 ccm.

Herz, on the other hand, NSU secured all records in the 350 cc to 1,000 cc classes with the two supercharged engines in the Delphin III, including the absolute world speed record for motorbikes at 339 km/h. This meant that in 1956 NSU held all the world records possible for two-wheeled vehicles.

The aerodynamic findings from 1951 also benefited racing at NSU. After the Rennfox and Rennmax racing machines had been improved from season to season in 1952 and 1953 in terms of engine power, weight, brakes and chassis, higher speeds could be achieved solely through aerodynamic aids.

The competitors from Moto Guzzi and MV Agusta already had fairings and thus came ever closer to the times of the NSU machines.

In order to maintain the lead and to be successful in the world championship in 1954 again, the NSU racing department experimented with many different fairings. During test drives at the nearby Hockenheimring on 15 July 1954, speed measurements were taken with different fairings. The test rider was the tried and tested Hans Baltisberger on a Rennfox with frame number R115401. The weather was dry and cloudy, the track length was 7.725 km and the time was between 18:00 and 20:30 h. With each fairing, one lap was ridden in a west-east direction and one in an east-west direction to compensate for any favourable currents. This produced the following average result:

Fairing type Delphin (version as in England): 161.5 km/h

Fairing type Assen (intermediate solution as in Holland): 169.5 km/h
Fairing type Blue Whale (design as at Solitude): 176.3 km/h

In order to get the whale fairing ready, they had even foregone the championship race on the Feldberg in 1954. But during the testing of the full fairings, problems with too high oil temperatures occurred. In addition, the whale fairings required a psychological adjustment of the drivers, because protected by the pulpit they could neither perceive the noise nor the pressure of the speed and were in danger of underestimating the speed. All of a sudden, the old braking points were no longer correct and the drivers inevitably had to move them forward. Maybe that was the reason – besides crosswind or too much lean – that the experienced Baltisberger crashed the Blue Whale on the Solitude. Nevertheless, it is undisputed that with the same engine power, the final speeds could be increased considerably and that the fairings offered welcome protection in the wet.

After the race in Bern, another aerodynamic correction was tried out, as NSU wanted to replace a lack of engine power with a successful streamline fairing before the last race of the 1954 season in Monza. They experimented with a rear fairing, but could only achieve a speed increase of 3 to 5 km/h on the long straight. At the end of this series of tests, it was decided to compete at Monza with three different rear fairings, but these made the machines quite unstable. Due to the tragic accident of Rupert Hollaus in practice, NSU withdrew all entries for Monza, so that these variants were not used at all in racing.