The Birth of Rotary Engines

In the early 1950s, NSU (Norddeutsche Automobil und Motoren AG) was already well-established as a prominent manufacturer of motorcycles and cars in Germany. However, it wasn’t until the company’s acquisition by the Italian entrepreneur Fritz Fuchs in 1956 that they began to explore alternative engine technologies. Among these innovative ideas was the rotary engine concept.

NSU’s engineers, led by Dr. Ferdinand Porsche’s former protégé, Albert Friedrich, started working on a rotary engine prototype in the late 1950s. The project, codenamed “Spider,” aimed to create a more efficient and compact powerplant that could be used in future NSU models. The Spider prototype featured a single-rotor design with an eccentric shaft, which allowed for a more direct path of combustion gases to the exhaust ports.

While the Spider’s innovative design showed great promise, it wasn’t without its challenges. The rotary engine’s inherent vibration issues and the difficulty of maintaining a stable air-fuel mixture at high speeds proved to be significant obstacles. Despite these hurdles, NSU continued to refine their prototype, recognizing the potential for a game-changing powerplant that could revolutionize the automotive industry.

NSU Spider: A Pioneering Effort

The early days of rotary engine development were marked by innovative experiments and bold ideas, but also faced significant challenges. NSU’s pioneering effort to create a viable rotary-powered car was no exception. In 1957, NSU engineer Felix Schottmüller designed and built the first prototype of a Spider rotary engine car.

Schottmüller’s vision was to create a lightweight, high-revving engine that would provide exceptional performance and fuel efficiency. He achieved this by using a compact, three-rotor design that eliminated the need for valves and camshafts. The resulting engine was remarkably light, weighing in at just 70 kg.

Despite its innovative design, the NSU Spider faced numerous technical hurdles. One major challenge was ensuring adequate cooling, as the high-revving rotors generated significant heat. Schottmüller overcame this issue by developing a sophisticated cooling system that utilized both air and oil to regulate engine temperature.

The NSU Spider’s rotary engine produced 100 horsepower at 8,000 rpm, with a maximum torque of 12 Nm at 6,500 rpm. While it didn’t quite match the performance of its piston-powered contemporaries, the Spider’s innovative design and exceptional fuel efficiency made it an attractive option for environmentally conscious drivers.

The NSU Spider may not have achieved mainstream success, but its groundbreaking design paved the way for future rotary engine developments. Its legacy can be seen in the numerous rotary-powered cars that followed, including those from Audi and Mazda.

Audi’s Acquisition and Innovation

**Innovative Synergies**

After NSU Spider’s pioneering effort, Audi took note of the rotary engine’s potential and began exploring ways to integrate it into their own lineup. In 1969, Audi acquired the rights to NSU’s Wankel rotary engine patents, solidifying their position in the development of this innovative technology.

Audi’s engineers worked closely with NSU’s designers to refine the rotary engine, focusing on improving its efficiency and durability. They also experimented with various applications, including a compact sports car concept that showcased the potential of the rotary engine for high-performance driving.

The collaboration between Audi and NSU led to the development of the 1.8-liter Wankel engine, which debuted in the Audi NSU Spider in 1970. This milestone marked the beginning of Audi’s commitment to innovative powertrains, paving the way for future developments in rotary engine technology.

Key Developments:

• Acquisition of NSU patents and technology • Collaboration between Audi and NSU engineers • Development of the 1.8-liter Wankel engine • Integration into the Audi NSU Spider model • Exploration of high-performance applications

Rotary Engine Evolution

As the 1980s progressed, Mazda’s rotary engine technology continued to evolve and improve. The company’s engineers worked tirelessly to refine the design, addressing issues with reliability and durability. One significant breakthrough came in the form of a new rotor design, which featured a more efficient air-fuel mixture and reduced emissions.

This innovation enabled the development of a more powerful and responsive rotary engine, as seen in the introduction of the Mazda RX-7 Turbo II in 1986. The car’s potent 1.2-liter twin-rotor engine produced an impressive 255 horsepower and 217 lb-ft of torque, making it a force to be reckoned with on the track.

Around the same time, Toyota also began exploring rotary engine technology, albeit with less success. The company developed a few prototypes but ultimately abandoned the project due to concerns over cost and complexity.

Key milestones:

  • 1986: Mazda introduces the RX-7 Turbo II with a more powerful and efficient rotary engine
  • Late 1980s: Toyota abandons its rotary engine development due to concerns over cost and complexity
  • Ongoing research and development by Mazda continues to improve the performance and efficiency of rotary engines

The Legacy of Rotary Engines

As the Rotary engine continues to capture the imagination and admiration of car enthusiasts around the world, its legacy as a pioneering technology in the automotive industry cannot be overstated. Born from the innovative spirit of engineer Felix Wankel, the Rotary engine’s unique design has inspired countless imitators and spawned a devoted following.

One of the most significant contributions of the Rotary engine to the automotive world is its ability to provide compact packaging without sacrificing performance. By eliminating the traditional pistons and cylinders, the Rotary engine is able to achieve a more efficient use of space, allowing for smaller, lighter engines that are capable of producing impressive power output.

  • This design advantage has been exploited by numerous manufacturers over the years, from Mazda’s iconic RX-7 to Nissan’s Z-car range.
  • The Rotary engine’s potential was first realized in the 1960s with the introduction of the Wankel NSU Spider, a sports car that showcased the engine’s ability to deliver high-performance while maintaining a compact footprint.

Despite its impressive performance credentials, the Rotary engine has also been criticized for its fuel efficiency and reliability. However, as technology continues to advance and new materials are developed, the potential for future improvements in these areas is vast.

In conclusion, the rotary engine’s journey began with NSU’s pioneering efforts, only to be further developed by Audi’s innovative spirit. Today, this iconic engine remains a testament to human ingenuity and the pursuit of innovation in the automotive industry.