I finally found out where the various mileage range estimates are coming from.
It appears that they are based upon one test where the car managed only 7.22km (a bit less than 5 miles).
MDI “corrected” that observed range of 5 miles with a series of estimates on possible future improvements that resulted in an estimated range of 150 miles. Although MDI no longer has these test results on their website, the wayback machine of archive.org has them available: http://web.archive.org/web/20070915070846/www.theaircar.com/tests.html
SUMMARY: Actual observed maximum range 7.22km. That will increase by factor 1.96 by reducing the weight of the car. Then increase by a factor of 3.9 by using bigger, higher pressure tanks and a change of engine design (7.6 times combined improvement). MDI figures that changing the design of the seals on the engine will expand the range by a factor of precisely 2.51. With these three potential improvement, the range would be 138km. Going from a 1 stage engine to 3 stages, with almost isothermic (almost perfect heat exchangers) will add another 38% to the range, for a total estimated improvement of 191.10 km rather than the observed 7.22 km (an improvment of 2,547%. On paper at least)
A range of 242.10km is estimated/predicted if the tank size is increased to 400 liters, and the pressure is increased to 350 bars/5,075psi.
————————————————
If one is able to so accurately predict performance of this prototype, then it is a trivial matter to estimate the performace of different models with different weights, tank sizes, and engines. Of course, such predictions are subject to a wide variety of errors and most car companies would do tests on real prototypes before scheduling mass production.
By: Charlie on November 15, 2008 at 3:47 pm
Charlie, this is a very good find. Some of this does look vaguely familiar to me, but it’s been a while since I’ve seen it. I’m still trying to place a date on this, but it does appear to be at least several years old. One indication of this is the mention of Brignoles, France as the location of their facility, with no mention, that I can find so far, of their current location in Carros France, which according to the MDI web site, they moved to in 2000.
You’re correct that this info is no longer on the MDI website. One would conclude this is because the developers consider the information outdated in no longer applicable…which either way would make sense if it is indeed almost ten years old.
I hesitate to make broad conclusions on the developers current state of progress based on a single decade old document, but after reading it again, here’s my take.
Math has never been my strong-suit, so putting aside all the equations, my bottom-line interest in this is if the developers can succeed in putting a vehicle on the road in mass quantities that is capable of running while burning little to no fossil fuels. To be honest, whether they can do it while achieving 50% efficiency or 80% efficiency is not the most important factor to me. This is especially true if the owner is using alternative energy sources to compress the air.
I want to see a car that can get me from point A, to point B, and back to point A again without getting stranded on the side of the road. If it turns out to be as clean and as cheap as they claim, while also being a decent economy class car, the average person will not care if it’s ONLY 50% efficient.
If I am correct on the age of these estimates, then a few things have happened since which one could consider encouraging;
For one, MDI/ZPM have entered the X Prize competition. This by itself proves nothing, but one would assume they have achieved something that is at least close to respectable, or else they’re in for a very big and very public embarrassment. Perhaps Guy Negre will show up in NYC with a state board and kite, hoping it will pull him over the finish line, but I doubt it. I’ve said before: the X Prize is do or die for the Air Car.
Second, MDI has introduced the Airpod, and has signed an agreement with Air France to test the vehicles for possible future applications in their facilities. This appears to be at least in part an attempt by MDI to publicly validate the compressed air engine. We’ll see how that pans out.
Third, TATA Motors, reportedly the worlds fifth largest auto maker, paid MDI nearly $30 Million USD for exclusive rights to the MDI air engine technology in India. According to MDI, they evaluated the technology for over a year and decided it was worth investing in. It’s true TATA announced it would be at least 2 years until the engines could be introduced, but this is hardly a surprise, though it was portrayed by many as a setback. It simply means TATA has to draw up a plan and find a way to build and implement an infrastructure that could support the vehicles there.
Like I’ve said, It’s all about the X Prize, and MDI must know that. They better deliver big time. It will either the best investment they’ve ever made, or it will sink the (air) ship.
By: Pneumatic Addict on November 16, 2008 at 2:02 pm
My prediction about the X-prize is that there will be some sort of mechanical failure that, unfortunately, prevents the MDI car from completing the course. The would make it so that there would still be nothing approaching an independent review of the MDI cars’ performance.
Air cars are definitely feasible, and HK Porter’s mine locomotives give us a pretty good idea of the performance possible. With a very light vehicle and large tanks ranges that just begin to meet users needs can be achieved. Kind of like the first generation of GM electric cars. The overall energy density of a compressed air system (without external fossil fuel reheaters) approaches that of lead acid batteries. The fact that you need to supply about twice as much grid power as with an BEV means that the compressed air car has a bigger carbon footprint on a per-mile operating basis, but this gets balanced out somewhat if the compressed air car can be made cheaper.
It just appears to me that MDI has repeatedly overestimated and overpromised. There are other people working on air cars. DiPetro in Australia is a good example of a company whose focus is first on engineering, has a reasonable correlation between promises and performance. He appears to be raising capital to support his work and to grow his company, but doesn’t seem to have the primary focus being to sell a massive franchising effort with the product design/marketing being in place to support the franchising business.
——————————
I note that the MDI website says that “A pilot-lot of 11 CityCATs 1 was manufactured for tests and development purposes. ”
(1st line under the photo on http://www.mdi.lu/english/cityflowair.php )
If these vehicles have reasonable performance, then sceptics can be silenced by letting a couple of automotive and/or alternative vehicle magazines run some simple tests. The most basic tests could be completed in one or two days:
1. Test top speed.
2. Test range as a couple of speeds — such as 30mph and 50mph.
3. A basic set of road tests normally performed …. acceleration time from 0 to 60mph (or alternatively 0 to 30 or 40mph), general observations on comfort, driving feel, noise levels, etc.
MDIs repeated claims, over several years, of performance far exceeding what other developers claim as performance makes me very sceptical. This is particularly true when this is coupled with their method of raising investment money, their repeated failure to go into production as scheduled, and the lack of independent test of their products, even though they claim to be near to production status.
I have been a limited partner and a technical consultant for venture capital companies, an angel investor in a startup, and before that drove the product planning for a company as it went from zero sales to greater than $1billion/year in 14 years. So it’s not like I don’t have some familiarity with product development and corporate finance.
By: Charlie on November 19, 2008 at 11:54 pm
The X Prize is MDI’s do or die moment of truth. Period.
If your prediction is correct Charlie, they should close up shop the next day. Or right now. Not only the interested public, but several current and potential biz partners including Air France and TATA Motors will be watching very closely, and a failure to even try to compete as you predict will be the end of it all. Given the time they have had and still have to prepare, there will be no acceptable excuses. No competent team would enter a race without being prepared for inevitable mechanical issues and spare parts. I will be the first to lose interest under those circumstances.
For right now though, I think there is enough reason to give them the benefit of the doubt, and at least assume they will show up at the starting line next September. What happens after that is what it’s all about, and I believe they not only know that, but are counting on it. Whether that is a wise strategy remains to be seen.
By: Pneumatic Addict on November 20, 2008 at 10:45 am
I finally found out where the various mileage range estimates are coming from.
It appears that they are based upon one test where the car managed only 7.22km (a bit less than 5 miles).
MDI “corrected” that observed range of 5 miles with a series of estimates on possible future improvements that resulted in an estimated range of 150 miles. Although MDI no longer has these test results on their website, the wayback machine of archive.org has them available:
http://web.archive.org/web/20070915070846/www.theaircar.com/tests.html
SUMMARY: Actual observed maximum range 7.22km. That will increase by factor 1.96 by reducing the weight of the car. Then increase by a factor of 3.9 by using bigger, higher pressure tanks and a change of engine design (7.6 times combined improvement). MDI figures that changing the design of the seals on the engine will expand the range by a factor of precisely 2.51. With these three potential improvement, the range would be 138km. Going from a 1 stage engine to 3 stages, with almost isothermic (almost perfect heat exchangers) will add another 38% to the range, for a total estimated improvement of 191.10 km rather than the observed 7.22 km (an improvment of 2,547%. On paper at least)
A range of 242.10km is estimated/predicted if the tank size is increased to 400 liters, and the pressure is increased to 350 bars/5,075psi.
————————————————
If one is able to so accurately predict performance of this prototype, then it is a trivial matter to estimate the performace of different models with different weights, tank sizes, and engines. Of course, such predictions are subject to a wide variety of errors and most car companies would do tests on real prototypes before scheduling mass production.
By: Charlie on November 15, 2008
at 3:47 pm
Charlie, this is a very good find. Some of this does look vaguely familiar to me, but it’s been a while since I’ve seen it. I’m still trying to place a date on this, but it does appear to be at least several years old. One indication of this is the mention of Brignoles, France as the location of their facility, with no mention, that I can find so far, of their current location in Carros France, which according to the MDI web site, they moved to in 2000.
You’re correct that this info is no longer on the MDI website. One would conclude this is because the developers consider the information outdated in no longer applicable…which either way would make sense if it is indeed almost ten years old.
I hesitate to make broad conclusions on the developers current state of progress based on a single decade old document, but after reading it again, here’s my take.
Math has never been my strong-suit, so putting aside all the equations, my bottom-line interest in this is if the developers can succeed in putting a vehicle on the road in mass quantities that is capable of running while burning little to no fossil fuels. To be honest, whether they can do it while achieving 50% efficiency or 80% efficiency is not the most important factor to me. This is especially true if the owner is using alternative energy sources to compress the air.
I want to see a car that can get me from point A, to point B, and back to point A again without getting stranded on the side of the road. If it turns out to be as clean and as cheap as they claim, while also being a decent economy class car, the average person will not care if it’s ONLY 50% efficient.
If I am correct on the age of these estimates, then a few things have happened since which one could consider encouraging;
For one, MDI/ZPM have entered the X Prize competition. This by itself proves nothing, but one would assume they have achieved something that is at least close to respectable, or else they’re in for a very big and very public embarrassment. Perhaps Guy Negre will show up in NYC with a state board and kite, hoping it will pull him over the finish line, but I doubt it. I’ve said before: the X Prize is do or die for the Air Car.
Second, MDI has introduced the Airpod, and has signed an agreement with Air France to test the vehicles for possible future applications in their facilities. This appears to be at least in part an attempt by MDI to publicly validate the compressed air engine. We’ll see how that pans out.
Third, TATA Motors, reportedly the worlds fifth largest auto maker, paid MDI nearly $30 Million USD for exclusive rights to the MDI air engine technology in India. According to MDI, they evaluated the technology for over a year and decided it was worth investing in. It’s true TATA announced it would be at least 2 years until the engines could be introduced, but this is hardly a surprise, though it was portrayed by many as a setback. It simply means TATA has to draw up a plan and find a way to build and implement an infrastructure that could support the vehicles there.
Like I’ve said, It’s all about the X Prize, and MDI must know that. They better deliver big time. It will either the best investment they’ve ever made, or it will sink the (air) ship.
By: Pneumatic Addict on November 16, 2008
at 2:02 pm
My prediction about the X-prize is that there will be some sort of mechanical failure that, unfortunately, prevents the MDI car from completing the course. The would make it so that there would still be nothing approaching an independent review of the MDI cars’ performance.
Air cars are definitely feasible, and HK Porter’s mine locomotives give us a pretty good idea of the performance possible. With a very light vehicle and large tanks ranges that just begin to meet users needs can be achieved. Kind of like the first generation of GM electric cars. The overall energy density of a compressed air system (without external fossil fuel reheaters) approaches that of lead acid batteries. The fact that you need to supply about twice as much grid power as with an BEV means that the compressed air car has a bigger carbon footprint on a per-mile operating basis, but this gets balanced out somewhat if the compressed air car can be made cheaper.
It just appears to me that MDI has repeatedly overestimated and overpromised. There are other people working on air cars. DiPetro in Australia is a good example of a company whose focus is first on engineering, has a reasonable correlation between promises and performance. He appears to be raising capital to support his work and to grow his company, but doesn’t seem to have the primary focus being to sell a massive franchising effort with the product design/marketing being in place to support the franchising business.
——————————
I note that the MDI website says that “A pilot-lot of 11 CityCATs 1 was manufactured for tests and development purposes. ”
(1st line under the photo on http://www.mdi.lu/english/cityflowair.php )
If these vehicles have reasonable performance, then sceptics can be silenced by letting a couple of automotive and/or alternative vehicle magazines run some simple tests. The most basic tests could be completed in one or two days:
1. Test top speed.
2. Test range as a couple of speeds — such as 30mph and 50mph.
3. A basic set of road tests normally performed …. acceleration time from 0 to 60mph (or alternatively 0 to 30 or 40mph), general observations on comfort, driving feel, noise levels, etc.
MDIs repeated claims, over several years, of performance far exceeding what other developers claim as performance makes me very sceptical. This is particularly true when this is coupled with their method of raising investment money, their repeated failure to go into production as scheduled, and the lack of independent test of their products, even though they claim to be near to production status.
I have been a limited partner and a technical consultant for venture capital companies, an angel investor in a startup, and before that drove the product planning for a company as it went from zero sales to greater than $1billion/year in 14 years. So it’s not like I don’t have some familiarity with product development and corporate finance.
By: Charlie on November 19, 2008
at 11:54 pm
The X Prize is MDI’s do or die moment of truth. Period.
If your prediction is correct Charlie, they should close up shop the next day. Or right now. Not only the interested public, but several current and potential biz partners including Air France and TATA Motors will be watching very closely, and a failure to even try to compete as you predict will be the end of it all. Given the time they have had and still have to prepare, there will be no acceptable excuses. No competent team would enter a race without being prepared for inevitable mechanical issues and spare parts. I will be the first to lose interest under those circumstances.
For right now though, I think there is enough reason to give them the benefit of the doubt, and at least assume they will show up at the starting line next September. What happens after that is what it’s all about, and I believe they not only know that, but are counting on it. Whether that is a wise strategy remains to be seen.
By: Pneumatic Addict on November 20, 2008
at 10:45 am