He studied from 1959 to 1962 at the former Baugewerkschule ( forerunner of the University of Kassel ) Civil Engineering and from 1962 to 1966 for his graduate engineer at the Ludwig- Maximilians- University of Munich.
1964 Stengel was hired by the Swabian amusement facility Bauer Schwarzkopf GmbH to perform static calculations for the first German steel coaster. Soon stem was working on the pure structural analysis far beyond: In 1976, he developed a solution to the problem of circular loops on roller coasters, which could not be achieved without some serious health for the passengers due to the physical forces acting until then. Stengel invented the first vertical loop of the postwar period by instead of a pure circular shape a clothoid chose what enables smoother transitions at entry and exit from the loop. This innovation was the one who made the vertical loop roller coasters only risk-free mobile. He was also the first to introduce the principle of the heart line to prevent health burdens in the design of roller coasters and thus made more outlandish elements driving possible.
Stem will continue to develop in their own engineering office roller coasters and amusement rides, which are used worldwide. Among others originate the Top Thrill Dragster at Cedar Point, which was the tallest and fastest roller coaster in the world from 2003 to 2005, and its successor, Kingda Ka, as well as the three largest wooden roller coasters in the world Son of Beast, El Toro and Colossos at Heide Park in Soltau from him. In addition, Son of Beast was the first wooden roller coaster with a vertical loop, which was made of steel, however, and was dismantled after the end of the season 2006. Meanwhile, the Stengel has worldwide design of 600 roller coasters developed (2012 ). The track is 500 Maverick at Cedar Point, Ohio, which opened in 2007.
In June 2005 he received an honorary doctorate from the University of Gothenburg.
On 22 January 2009 Werner Stengel was awarded the Federal Cross of Merit for his achievements in Fahrgeschäftsbau and the establishment of international standards in this area.