Short Story: The Truth About Rotary Engines

Since its introduction, more than 60 years ago, the rotary engine was considered the pinnacle of engine development. At first glance, people thought it was destined to replace other engine variants. 

Due to the smooth operation of the engine, there was hardly any vibration. The power that the initial rotary engines were able to put out in such a small form factor was astonishing. In fact, it persuaded many major car manufacturers at the time to start experimenting with the “Wankel” engine. Some of them even found their way into big series of production cars.

But soon enough it all went downhill… Read on to learn the story and the truth about rotary engines!

A Little Background About Rotary Engines

Before we dive deeper, let’s cover the basics first. The rotary engine was developed by Felix Heinrich Wankel – hence the name “Wankel” engine. He was working on a new engine design since the 1930s but it wasn’t until 1954 that he invented an actual rotary piston engine. 

In 1957, NSU (German car manufacturer, predecessor of Audi) employee Hanns Dieter Paschke designed the rotary piston engine, which is now known as the Wankel engine. The engine had an eccentric shaft with a low imbalance, which eliminates the vibrations with a balancer shaft. The new engine ran for the first time in an NSU Prinz III in 1960, and in 1963 NSU presented the Wankel Spider, the first production car with a Wankel engine. 

In the same year, Mazda shows the first test car with the technology, and a year later the NSU goes into series production. However, the engine is only successful for Mazda, and Felix Wankel was lucky enough to sell engine licenses to several companies as the engine design proved to be functioning.

Felix Heinrich Wankel never had the chance to go for a ride with a rotary-powered car. Not only that, he never got to drive. Due to his extreme short-sightedness, he never even got his license. He passed away in 1988.

How A Rotary Engine Works

Trying to describe the operation of a rotary engine with words is futile. Watch the video below for a simple and great visual explanation of the inner works of a Wankel engine.

How Rotary Engine Works by Matt Rittman

How The Rotary Engine Killed A Car Manufacturer

The story of the before-mentioned German car manufacturer NSU is crucial to the story of the rotary engine. 

NSU was the first brand to actually gave the rotary engine a chance. But it did not turn out to be the smartest decision. As they were testing the engines, it was clear that it was nowhere near ready to hit the road.

Their rotary engine was overheating, the spark plugs burned out, and the consumption of oil and gasoline was terribly high. And that was not the worst part, it was the rotor piston seals that caused the most headaches. Hard steel seals were tried, which were resistant to wear, but they often cracked and dented the engine casing. The soft carbon strips worked great for a few hours and then the engine would stop… There was no solution in sight.

The first production NSU with a rotary engine called the NSU Spider Wankel was a catastrophe. It was unreliable, prone to complete failure, and wasteful. From 1964 to 1967 only 2,375 examples were produced. This is still a lot considering that most cars did not reach the 20,000-mile mark before needing an engine replacement.

NSU recognized its mistakes and made sure they address them in the release of the futuristic NSU Ro 80. And they did, to a certain point. The Ro 80 was a hit, in fact, it even won the title for the European car of the year in 1967. However, the engine-related problems were far from over.

The numerous failures of the rotary seal and consequential engine failures led NSU to replace numerous engines and it eventually led the company to the ground. The company was eventually bought by Volkswagen and added to the Audi NSU subsidiary.

Enter: Mazda

There was never any doubt about the engineering genius of the Japanese. This story only supports that fact. While the Europeans could not figure out the rotary seal issue to save their lives, Mazda introduced the rotary-powered Cosmo.

So what was so special about the Cosmo? Well, for starters, it had no problems reaching 60,000 miles and more without needing an engine replacement. When the Europeans asked how many rotary piston seals they replaced to reach that mileage, their answer was: none!

They resolved the infamous seal issue and perfected the rotary to the point where it made sense to keep the engine not only for production cars like the RX-7, and RX-8 but also for their high-end Le-Mans racing cars. 

Truth be told, even in cars like the RX-8, the rotary Wankel engine was far from perfect. But despite the numerous engine failures, there is an entire community of rotary enthusiasts that are patiently waiting on the renaissance of the Wankel engine. It is an illustrious design, attracting many for its numerous benefits and not all hope is yet lost.

Is There A Tomorrow For The Wankel?

There is! And it is at our doors. 

Mazda is the only car company that sticks to technology. The new and so far only electric SUV Mazda MX-30 will soon receive a range extender that works according to the Wankel principle. As a combustion engine, the Wankel engine will then charge the battery of the MX-30 and thus extend the range.

Mazda recently filed a new patent in which three electric motors, two power storage devices (capacitors), and an internal combustion engine work together. The advantage of incorporating a Wankel engine are small size, low weight, and smooth engine operation. Ideal for electric vehicles that otherwise hardly produce any vibrations. 

We are excited to see what the future brings for rotary engines, and we truly hope it resolves some issues that have been plaguing an otherwise genius engine design!

More To Explore

Track Your Order