Future or Fantasy? We Take a First Ride in MDI's Compressed-Air Car

By John O'Dell December 27, 2008

Luxembourg-based Motor Development International (MDI) is raising the hopes of green-car technology fans, and the eyebrows of skeptics, with its promised line of zero-emission cars powered by compressed air.

Green Car Advisor contributor Nick Kurczewski recently paid a visit to MDI's research and development center in the south of France, and climbed aboard the company's AirPOD city-car, the first North American journalist - he was told - to be treated to a ride in one of the low speed city cars.

Here's his report.

AirCar_01.jpg First Ride: MDI's Air Car

The goal of the trip was to to see first-hand if an air-powered car has real market potential, or whether the idea is just a lot of hot air, impractical for everyday use.

Never camera-shy, correspondent Nick Kurczewski poses in rear-facing passenger seat of MDI's AirPOD compressed-air car.
The technology seems feasible. MDI is developing several small and lightweight vehicles, but the basic blueprint is the same and involves the use of refillable, on-board, high-tech, carbon-fiber, pressurized air tanks (built by the European aerospace firm EADS), and a piston engine specially adapted to run on air power.

The pressurized tanks store compressed air that runs the engine, which in turn sends power to the driven wheels.

Behind the Wheel

There have been quite a few reports about the air cars, including ours last October, but little in the way of in-the-car impressions. So Green Car Advisor arranged to visit MDI's R&D faciltiy to bring our audience the experience of air-powered motoring - albeit from the passenger seat.

We were given a ride in a prototype of MDI's four-seat AirPOD.  Driving was denied us because the vehicle isn't finished - refinements are still being made on an almost daily basis - and MDI decided it wasn't ready for a journalist to get behind the wheel.

Not that there is a wheel to get behind. Controling the car is done with a joystick that's mounted to the right of the single front seat.

Push forward to accelerate. Pull back to stop. Move the stick left or right to turn. It's as simple as that.

The driver enters the car via the huge glass windshield, which hinges upwards for easy access. There are no foot pedals, and in this prototype, no dashboard or instruments, although MDI is working on a simple digital display for things like speed and remaining range.


The MDI AirPOD, seen from the front, with  the company's air compressor station to the left.

Whirling Dervish

The AirPOD is a four-wheeler, regular-sized in the rear and two very small wheels mounted up front almost directly beneath the driver's feet.

These tiny shopping-trolley front wheels probably don't do much for the AirPOD's racetrack prowess, but they make for impressive low-speed cornering acrobatics. The 106-inch-long AirPOD can perform a 360-degree turn within its own petite shadow.

Behind the driver is a rear-facing bench seat with room for up to three passengers. As with access to the driver's seat, entry to the passenger cabin is achieved via a wide-opening glass door.

Between and underneath the seats is the heart of the AirPOD, a "mono-energy" air-powered, one-cylinder air engine and its pressurized air tank.  

(MDI is also building what it refers to as "dual-energy" models that use a secondary fuel such as gas, diesel, or a biofuel, in an external combustion chamber that then heats the air in the engine. This expands the air, increasing the car's range and top speed.

Low Speed Only

For now, the mono-energy AirPOD is limited to speeds below 70 kilometers per hour (43 mpg), or below 45 kilometers (28 mph) in markets where the car is elgible to be driven without a driver's license.

The AirPOD's current range is quoted at 136 miles in MDI's sales literature.

With the equivalent of only 5.45 horsepower, break-neck performance is not the AirPOD's forte.

In fact, our ride was momentarily curtailed when the AirPOD's engine started chugging slower and the car's speed kept dropping.

AirCar_05.jpg Realizing a fill-up with compressed air was needed, the driver hopped out of the car and plugged the AirPOD into a bank of air tanks located at MDI's factory.

MDI says that refueling with a commercial compressed air system should take less than one minute, though our refueling session stretched to about four. Refueling at home, using a traditional plug and outlet to power the on-board air compressor, takes between 3 to 4 hours.

Once our driver topped up the air (left), we clambered inside and onto the rear-facing bench seat.

Visibility is excellent, there is a wide view of the world outside thanks to the large glass hatches and porthole-like side windows. The cabin is airy, funky, and modern. It feels as much like a chic lounge as it does an automobile.

Needs Finesse

On the move, though, the AirPOD is not so urbane. There was a slight vibration from the engine and a lack of sound insulation that made it a bit noisy inside the cabin as the plastic body panels amplified he the motor's mechanical din.

MDI representatives said the test model we rode in doesn't have sound insulation installed and that production models with insulation should be noticeably quieter (and a bit heavier) than this prototype.

MDI also stressed that the suspension is being fine-tuned, though we found no serious faults with the current arrangement. At the low-speeds of our demo run, the AirPOD coped well with most bumps and imperfections.

The car's cornering abilities are even more impressive from inside, where a couple quick 360 degree turns left us amazed at the maneuverability (and awfully dizzy, as well). Squeezing into tight parking spots or crowded traffic should not pose a problem in the highly maneuverable AirPOD.

Pricing is still being determined, though MDI has suggested a €6,000 ($8,300) price-tag for mass-market AirPODs.

EV Alternative?

The air car is a zero-emission vehicle that MDI hopes will be a viable alternative to the electric-powered cars being being developed by almost every major auto company.  

"I'm not an ecologist who made a motor," MDI founder Guy Negre said during an interview at the company's R&D facility in Nice, France. "I'm a car guy who made a clean engine."

minicat-01-550x365.jpg Negre, who has been booed more than he's been cheered,  told Green Car Advisor that he is not bothered by criticism of air-powered engines.

"Whenever something new comes along, you always have people with a very favorable opinion and others that are very critical."

MDI's Guy Negre with 'MiniCat' air-car concept.
Critics center their complaints on the air car's limited driving range and performance. In simple terms, a motor running on compressed air packs less of a punch than an identically sized engine running on gasoline or diesel, or than an equally-sized electric motor running on battery power.

Less Oomph  

That's because compressed air, pound for pound, is less energy dense than these other forms of automotive fuel.

MDI representatives readily admitted during our visit that, if driven at highway speeds and mounted in a traditional vehicle, an air-powered engine would have a severely limited range.

"There's no way to make 4x4s that run on air," Negre admitted. "So we're going to make cars that are more adapted to customers actual use."  

That translates as low-speed, lightweight city cars.

The first production models are only months away and, Negre said, "should be available in March or April."

Air Cars and Airports

Initial models will be used in company fleets by Air France and other groups  and will be closely monitored by MDI, said Negre.

The company in October announced an agreement with both Air France and the Dutch airline KLM to test the company's futuristic-looking "AirPod" model.

The six-month program will see the tiny cars ferrying passengers throughout Charles De Gaulle Airport in Paris and Schiphol Airport in Amsterdam.

Operating data and troubleshooting form the airline tests will be used to get the cars ready for retial sales late next year or in early 2010, Negre said.

A Sub-$5,000 Model?

He added that MDI's basic model, the OneFlowAir, should go on sale in Europe with a starting price of about €3,500 ($4,890).  

MDI also is working with India's largest auto manufacturer, Tata Motors, which has an exclusive license to manufacture and market air cars in India.

Tata shot to prominence during the New Delhi Auto Expo 11 months ago when when it debuted its utra-cheap Nano city-car. The starting price of the standard gasoline-powered Nano will be roughly $2,100 when - barring more of the labor and financial troubles that have been plaguing Tata - it goes on sale next spring.

Tata has not released specifics about pricing, sales dates, or plans to use compressed air technology, but is expected to focus its exclusive use of MDI's air-powered motors on the Nano.

Indicating that he's in the market for other partners, Negre said that Tata wouldn't be able to market the air car outside India without negotiating a new contract.

All of this means that, for now, an air-powered automotive future remains tantalizingly out of reach no matter if you live in New Delhi, or New York City.

Picky, Picky

U.S. sales are being considered, though at the time of our visit Negre would not be drawn into saying which models might appear stateside or what U.S. pricing might be.

"It's not easy breaking into the American market. It's a very particular market and the Americans are a particular people," he said.

"For the moment, no agreement has been reached [regarding U.S. sales]"  although, he said, there have been initial talks - with a financial institution he declined to name - about setting up a U.S. distributorship.

Negre ignored the fact that he'd discussed a late 2010 U.S. sales launch in his earlier interview with Green Car Advisor, which led us to conclude that even with all that compressed air on hand, we're not holding our breath.

Nick Kurczewski, contributor

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Click here to comment on this entry.
brn says: 5:28 AM, 12.29.08

43 mpg -> 43 mph

"The air car is a zero-emission vehicle"

They need to come up with a better term. While the vehicle itself doesn't emit emissions, emissions are likely emitted while compressing the air. How about an "emissions transfer vehicle"?

"range is quoted at 136 miles"

From the article, this seems doubtful. Did they really not make sure it had a full tank before demoing the vehicle to the press? Of course it was full and of course it ran out after just a few miles.

While such a vehicle may have specific purpose applications, I can't see it for general use on city streets. Performance is poor. Range is poor. Safety didn't get mentioned. How safe do you really feel with nothing but a piece of glass between you and the car you (slowly) hit?

redliner says: 12:41 PM, 12.29.08

"How safe do you really feel with nothing but a piece of glass between you and the car you (slowly) hit?"


I don't think this would work in the USA. Do you see golf carts on the road?? Because thats what this is. I think it would be perfect for airports and other large complexes.

aircarsceptic says: 12:35 PM, 12.31.08

The main engineering challenge is the low energy density of compressed air, which makes it difficult (or impossible) to achieve a reasonable operating range. It is interesting that the prototype ran out of air while you were being taken for a test drive.

Did MDI tell you the ACTUAL operating range of the prototypes (as opposed to the 136 mile claim for the always "soon to be launched" mass production vehicles) ?? The only test results that MDI published showed their car running out of compressed air after only 7.22km. They have taken it off their website, but it is still available in the wayback machine: http://tinyurl.com/mditest results

'The first production models are only months away and, Negre said, "should be available in March or April." ' --- and I have a bridge in Brooklyn that I'd like to sell you.

Guy Negre has announced "production soon" almost every year since 2000. After a few years, MDI then announces a new model and everyone forgets about the past claims and promises. Google "e.volution car" or "eolo car" or "Mexico City taxis MDI" to pull up dozens of old articles.

"Negre ignored the fact that he'd discussed a late 2010 U.S. sales launch in his earlier interview with Green Car Advisor, which led us to conclude that even with all that compressed air on hand, we're not holding our breath." ---- he just assumed that like most journalists, that you had no knowledge or memory of previous claims and production promises.

aircarsceptic says: 12:40 PM, 12.31.08

bad link in the above: the MDI prototype test results should have been
http://tinyurl.com/mditestresults , which points to http://web.archive.org/web/20071011200005/http://www.theairc

aircarsceptic says: 2:58 PM, 11.16.09

A couple of people from a French compressed air car forum visited the MDI factory and dug deep enough to get a few answers.

The range of the current generation AirPod (and apparently the one that the author of this article tested almost a year ago) is ONLY 20 - 30 KILOMETERS. That's just 12 to 19 MILES!

As always, MDI says that they are working on a more efficient engine, a bigger compressed air tank, and the next generation will have 220 km / 137 mile range.

Maybe. But that has been the story for the last 10 years. It is interesting that it takes a full year before they admit that their prototype has nowhere near the range they are claiming, but I guess that if you don't have a pressure gauge visible and just let journalists go putt-putt around the parking lot for short rides that most won't ever figure out that the claimed range is a myth.

aircarsceptic says: 3:00 PM, 11.16.09

In another development, MDI and Zero Pollution Motors are no longer entered in the Progressive X-Prize competition.

No explanation of why they either withdrew or were disqualified.

John O'Dell says: 11:20 PM, 11.18.09

They didn't make the final cut. Guess the judges didn't think they could build a real market case for 'em, which is one of the criteria.

aircarsceptic says: 8:46 PM, 05.20.10

So, now it's May 2010. We are still waiting for the AirPod to go on sale. Indeed, we are still waiting for the AirPod design to be completed.

The airline KLM tested a couple of prototypes and found that the range was about 15km. So the range has doubled since the 2003 tests of an MDI car that ran out of air after only 7.22km.

It appears that the prototype that Nick K. tested for this article had an 84 liter, 248 bar tank rather than the 175 liter, 350 bar tank shown on the spec sheet.

Due to the abysmal 15km actual range, MDI has decided to increase the tank size. In March 2009 (3 months after this article) MDI announced that the 175 liter tanks would be received by December 2009.

Now it turns out that the MDI never contracted for the larger tanks. So MDI is now looking at either 200 liter or 230 liter 350 bar tanks.

Whether or not THESE tanks have been ordered is unknown.

It looks like Nick K. was truly taken for a ride back in December 2008.


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