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Making a car move is simple: you need a motor and power source.
For most, that means petrol, diesel, electric or a combination of them. Yet there are other options out there, some more practical than others, so what else could you be using to drive?
From steam to pedal power, there are more ways to make a car move than you might think. Here, we have the run-down on the strangest options out there:
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Steam
Steam power has been around for centuries and gave petrol a close run for its money in the early days of the car. Now, steam is seen as a very unusual and archaic choice for powering a vehicle that doesn’t run on tracks, despite there being some advantages to this form of propulsion. For starters, steam can be generated using all sorts of fuels, so you’re not limited to a single source for creating the necessary heat.
Another advantage is that steam can be super-heated to be a very efficient method of powering a vehicle. But, ultimately, the noise, smell and weight of steam engines meant they were impractical, and this failure gave rise to the widespread use of the internal combustion engine.
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Propeller
The cross-over between car and aero design in the early part of the 20th century inevitably led to some cars trying propeller power. Among the notable attempts at this point are the Helicar (pictured)that was trialled before the First World War and the later Jameson Prop-Car. The fundamental problem all propeller-equipped cars faced was one of drag.
Tyres on the ground create a lot of friction compared to a plane suspended in the air, so prop cars were slow even when fitted with powerful engines and big blades. Regardless of the size of the propeller, these cars were also dangerous and never caught on.
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Rubber band
Rubber bands are fine for powering toy cars, but scaling that up to a full-size vehicle has proved impossible for even the most determined advocates of this type of propulsion. The problems arise from the failure to generate enough power to twist the band into tension so that it stores energy and then releases it in a controlled manner over a prolonged period to sustain a journey.
However, the idea of the rubber band has inspired other types of propulsion, notably wind-up hybrids. They use a spinning flywheel to store energy that would otherwise be lost in the vehicle’s transmission that can be used to give an extra boost when needed. AFS Trinity patented its Extreme Hybrid technology and developed a prototype car (pictured) that could drive 40 miles on EV power alone as well as deliver 150mpg.
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Walking
Don’t go thinking this is a Flintstone-style form of power with feet sticking out of the floorpan. Instead, walking cars are a solution that have been around for a long time to allow a vehicle to tackle terrain that wheels find difficult. The premise being that if a human can walk up inaccessible routes, why can’t a car?
The latest to try this theory is Hyundai with its Elevate concept that it showed off at the 2019 Consumer Electronics Show in Las Vegas. With four bending ‘legs’, the Elevate has been designed to deal with awkward obstacles such as stairs and Hyundai says cars with this type of system could be a huge boon to disabled drivers who find it tricky to reach their car, so the solution is to bring the car to them.
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Tracks
Using tracks in place of wheels and tyres is a great way to improve a car’s go-anywhere ability. The tracks spread the weight of the vehicle over a much larger footprint and offer far greater traction, which is why heavy tanks can achieve what they do. However, there are downsides, such as tricky manoeuvring, extra width and much greater drag that reduces performance and economy.
Yet tracked vehicles still hold a fascination and Nissan is one the most recent to dabble with this technology. Its 2017 Trail Warrior was based on an X-Trail and used individual sets of tracks for each wheel hub, similar to the Cuthbertson system used on Land Rovers.
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Pedals
Pedal power is perfect for bicycles and even mopeds, yet has not been embraced in cars. For some, this is madness when there’s a source of power sat in the car not being used. Moving the idea of a pedal car on from a child’s toy, there are several companies offering either pure pedal-powered machines such as the Scuderie Campari (pictured), while others are combining pedalling as part of a hybrid package.
Actor and inventor Rich Kronfeld has come up with the Raht (recumbent automotive human transport) that uses pedals to power his three-wheeler and charge a battery pack. With the two working together, the Raht can reach 100mph and Kronfeld says it offers the economy of a bike with the safety of a car.
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Magnetic
The power of magnets has been used in cars’ suspension and also to create ‘floating’ vehicles using Maglev technology on tracks. However, magnets can also produce a forward motion when two are attached to the positive and negative ends of a battery. This produces a perpendicular force that drives the motor forwards.
There are drawbacks to this as a potential power source, however. Not the least is that roads would have to become conductive for this to work as both ends of the battery have to be in contact with each other. Also, the amount of propulsion generated is small compared to the energy required and the vehicle would only travel in one direction, so reversing would be tricky. This is why magnets are fixed in position in electric motors so it’s the drum that rotates.
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Air
Making compressed air work as a source of propulsion has been tried many times and with limited success. Tata tried with its Nano, but it’s MDI from Luxembourg that is taking this technology further. It’s developed the AIRPod (pictured) that uses a two-cylinder reversible motor to compress air into a pair of carbon fibre storage cylinders. This is then released back through the engine to power the wheels.
MDI says the AIRPod is capable of up to 93 miles on a single compressed air fill and there are no emissions. The only energy used is the electricity when powering the compressor to store air. The AIRPod is available to buy now and costs from £8500 (US$10,880).
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Nuclear
Nuclear energy is used to generate much of the world’s electricity supply, so why not fit it directly into an EV car? The idea sounds simple and it’s tempting when just 500 grams (1.1 lb) of highly enriched uranium can power a Nimitz-class aircraft carrier. However, the dangers of nuclear material are well known and the weight of the shielding that would be required to protect the car’s occupants and others around it rules it out.
This didn’t stop Ford thinking about nuclear power in the 1950s with its Nucleon concept (pictured). The idea was that a single fill would allow it to travel 5000 miles before a new reactor was swapped in. A major downside was the scale model produced showed the reactor was so large it left little space for passengers.
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Turbine
The Jet Age of the 1950s produced wonderful styling, but it also prompted research into real jet-powered cars using gas turbine technology that was also being developed for use in the aero industry.
Curiously, it was conservative Rover that pushed the idea furthest with its JET 1 prototype, which was a two-seater based on its P4 saloon. This led to the Rover-BRM racer (pictured) that competed at Le Mans with Graham Hill and Richie Ginther sharing the driving.
In the USA, Chrysler came up with its appropriately named Turbine Car that was a more practical-looking proposition. Fifty Turbine Cars were tested by the public and response was positive. However, concerns over maintenance costs and emissions killed off the project.
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Archimedes screw
The Archimedes screw is a very efficient way to pump water, but its record as a means of vehicle propulsion has been more chequered. Both the British and Germans experimented with the notion during the Second World War for amphibious vehicles as the screw allows heavy cars and trucks to drive on boggy terrain and through water.
It was the Russians, though, that took the idea further and made it work for use in the country’s snow-bound regions. In these conditions, side-mounted screws on either side of the vehicle let it slice across frozen ground with ease. The problems started as soon as the truck encountered normal roads where they were all but useless.
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Two-stroke
A two-stroke engine has some key benefits over the much more prolific four-stroke motor. These include lighter weight, fewer moving parts and high power output for the given capacity. It’s why two-stroke engines were very popular for motorcycles and small dinghys that didn’t require huge amounts of torque to overcome their weight and inertia.
Therein lies one of the problems for two-strokes as a source of power for cars: poor torque. Another is two-stroke require a pre-mixed fuel with oil in it to lubricate the cylinders. This leads to the tell-tale smoke from the exhaust, which is incompatible with modern emissions legislation. It didn’t stop the likes of Saab, DKW, Suzuki and Subaru among others from using two-stroke to good effect in the 1950s and 1960s.
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Sail
You need two things to make a sail-powered vehicle work: wind and plenty of open space. Neither can be guaranteed on the road and is why this isn’t a viable solution to zero emissions propulsion. However, this is not to dismiss wind power altogether because rotor-powered vehicles have been made to work.
A rotor-powered vehicle is, in essence, a wind turbine on wheels. It uses a ducted fan that’s turned by wind energy to generate electricity that powers a motor attached to the wheels. The car can charge up while parked and also use regenerative braking to recharge. The downsides are the size of fan required and the drag it creates when not in use.
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Rotary
Rotary engines don’t have reciprocating pistons like most internal combustion motors. Instead, they have a rotor that turns inside a chamber, separating out the four-stroke process into individual sections of the engine rather than it all happening in the same chamber. It makes for a compact and powerful motor for the capacity size.
It sounds ideal and Mazda has championed the rotary engine, although Citroën and NSU has dabbled with it in the past. Light weight is a defining character of the rotary motor, as well as few moving parts. However, it’s proved hard to make rotary engines sufficiently economical and emissions-friendly.
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Gravity
Gravity is great when you’re going down a hill in a car, but it’s your enemy when driving up. It’s a very one-sided equation for use in a car and is why it’s never been embraced other than as a form of motorsport using everything from soap-box karts to custom-made racers.
Yet gravity still plays a part in how some cars can perform to their best. Hybrids and EVs that use regenerative charging can make the most of downhill sections to ease off the acceleration and use gravity to maintain speed and top up battery power. Hypermiling drivers use this coasting to maximum effect to travel some way up the next slope without using any more fuel.
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