Gyro Bus – The All Electrical Bus from the 1940s

Public transportation is intended to be a form of transportation that connects cities and countries together and at the same time reduces air pollution and emissions. But today, most public transportation uses petroleum-based power sources. In the best case, they are electric vehicles that need batteries to be powered.

But what if we have a bus that needs no gas and no batteries to work?!

We have it! It’s the GyroBus!

Source: By Vitaly Volkov / wikicommons

In the 1940s, Swiss inventors created a new type of zero-emission electric bus that stored energy in a giant rotating flywheel instead of rechargeable batteries. To put it simply, they wanted a vehicle that was less bulky and less likely to interfere with nearby electrical lines.

Source: kosubaawate.blogspot

It was common in many Swiss cities at that time to utilize electric trolleybuses as public transportation. Rails, on the other hand, limited travel and the installation of overhead cables over new lines were too expensive. And batteries had certain flaws, just like today’s technology.

As a result, in 1946, Maschinenfabrik Oerlikon’s head engineer, Bjarne Storsand, came up with the concept of the Gyrobus.

How the GyroBus works?

In order to operate the Gyrobus, a generator delivered electricity to an electric motor, which in turn powered a spinning flywheel to store energy. Three booms on the vehicle’s roof were used to spin the flywheel at charging stations.

After reaching a maximum speed of 3,000 revolutions per minute, the flywheel is fully charged, and the bus was able to go up to 6 kilometers at speeds of 50 to 60 kilometers per hour, depending on the load and the inclination of the road. Vehicles at a Yverdon-Les-Bains facility have been known to go up to 10 kilometers on a single charge.

What is the flying wheel?

Source: By Vitaly Volkov / wikicommons

A flywheel is simply a mechanical battery that revolves around an axis of rotation. It stores energy in the form of kinetic energy. It operates by rapidly accelerating a rotor and retaining the energy in the system as rotational energy.

Flywheel energy storage has great promise as an alternative to traditional lead-acid batteries.

In addition to the gyro bus, NASA’s G2 flywheel for spaceship energy storage also utilized the flying wheel.

Source: NASA

Recharging Process

Source: By Smiley.toerist / wikicommons

Three booms on the vehicle’s roof were used to provide the flywheel with electricity. It took up to 40 minutes to recharge the flywheel from a complete stop but just a few minutes to add more energy to it once it was spinning. The supply voltage was raised from 380 volts to 500 volts in an effort to shorten the charging time.


As a result, the bus’s flywheel was constantly recharged by strategically located charging stations to prevent any reduction in the vehicle’s efficiency or performance. In Yverdon-Les-Bains, the 4.5-kilometer track contained four recharging stations.

GyroBus Advantages & Disadvantages

There were several unforeseen effects of having a massive flywheel in the bus, some of which were good and others were not.


  • The bus is pretty quiet since no any combustion is taking place.
  • Zero-emission. The gyro bus is considered a pollution-free vehicle since no combustion and no batteries are needed. The only source of pollution is the generators used to charge it.
  • Gyro bus works without rails, which means the route could be changed easily when needed.


  • The flywheel is heavy. For instance, a gyro bus that could carry 20 persons for just a range of 2 kilometers requires a flywheel of about 3 tons.
  • It is a bit challenging to turn the bus due to the flywheel’s gyroscopic effect.


GyroBus was once a great innovation. It solved the problem of having fixed railways and reduced pollution. But with time and development, this vehicle disappeared.

Gyrobus needs a lot of development to solve its problems. It needs an extended range, faster charging, and to solve the high-weight flywheel issue.

This vehicle could be one day a solution to the pollution problem the world is facing nowadays. But not that soon…

What do you think of the gyro bus? Is it a technology that needs to be bought back into action?

For further more detail on the Gyro Bus watch the following video:

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