More details on the RORMaxx Formula AE wind-assisted car
Click above for a high-res gallery of the RORMaxx
The RORMaxx Formula AE student project got some attention when we first posted on it a few weeks ago. AutoblogGreen reader Jesse K. wanted to get some information directly from the horse's mouth and contacted Rory Handel (one of the students involved) about the technical features of this wind-assisted car. Basically, the students don't think they've rewritten the rules of physics here, as you can see in the email thread of Jesse and Rory's conversation pasted after the jump. Rory gives us a little more detail on the "Air Flow Recovery" system. It's not perpetual motion, just trying to snag some extra energy as the car moves down the street. In the computer models and in the lab, at least, the system works. Full details after the jump. If you missed the first post on the RORMaxx, click here.
Gallery: RORMaxx
EMAIL THREAD:
Jesse: If you really thing that putting wind turbines in ducts on a car is going to give a net increase in electrical energy, you are sadly mistaken. You may want to rethink your physics if you want to attract investors.
Rory: I'm sorry if you were misinformed about our intentions. We are clearly not going to make the mistake of pursuing a perpetual motion machine; that's ludicrous. We are rather exploring the possibility of a "range" extender using our 'Air Flow Recovery' system for our plug-in racing vehicle, which has already proven to work in our lab. A full computational fluid dynamics analysis is currently under way, and the drag of the system has proven to be minimal.
Just out of curiosity what led you to believe that we were trying to make a perpetual motion machine?
And just to conclude this rather dissatisfying email, I would like to mention that the profit is in the journey whether it is successful or not. I don't mean to offend you by any of this, I just felt it was important to respond. Thanks
Jesse: Can you provide any specifics of how your system is supposed to function? Because you seem to be claiming that you can recover some 20% of the energy from the supercaps+ batteries without adding to significantly to drag, where does this 20+% energy come from? Sounds like perpetual motion to me.
Also.You also make no mention of a kinetic recovery system. Why not? Regen from braking is a proven technology.
Rory: The way in which the system will specifically work is classified, but I can tell you that there will be a flap that closes at the point where the energy lost under the drag of the ducting is greater than the energy recovered from air. Our system is currently giving us 200 volts at <40 mph wind speed which is actually a 50% efficiency increase but that's excluding energy lost under the drag of the system at those speeds, however there is a substantial net gain. Also, 40 mph is less than 1/2 average race speeds.
As far as KERS goes, our system can be more cost effective believe it or not. All KERS available is quite expensive, but we might incorporate it in another chassis.
I'm not sure if you have ever built a vehicle from scratch, but this has been in development for much longer than you have been seeing on the internet.
I hope this information answers your questions. Thanks.
Reader Comments (Page 1 of 1)
Chris M 4:58PM (1/31/2009)
Jesse certainly got it right. Sorry to say it, but it sounds like Rory doesn't really understands the problem. Electrical power isn't measured in "volts", it is irrelevant what voltage they are producing without also knowing the amperage. I can generate over a thousand volts just shuffling my feet across the carpet, but with negligible amps, it amounts to very little power.
It looks like they are going to have to learn the facts of physics and aerodynamics the hard way, but at least it is a lesson they won't forget.
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H4MM3Rd 7:58PM (1/31/2009)
I x E
I x E x PF x 1.732
;)
sp 5:22PM (1/31/2009)
Actually it could work if the flaps only open when you hit the brakes. Basically it is needlessly complicated regenerative braking.
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jim Stansbury 7:52PM (1/31/2009)
Rory,
I give you credit for doing SOMETHING. You have to stick your neck out to accomplish anything valuable. I like to remind myself of the saying "Those who say it cannot be done are usually interrupted by those doing it."
I wonder what similar , better, projects your naysayers can challenge you with?
You are correct in that it can be done, and we are also going to prove it, just with a bit less eloquence, than you are doing. You can see the Physics Lab of Lake Havasu in action at the Progressive Automotive X Prize next year with a similar app., as well as some others unconventional ideas generating some sparks.
Best of Luck, keep on rocking the free world.
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Nick 8:42PM (1/31/2009)
"a flap that closes at the point where the energy lost under the drag of the ducting is greater than the energy recovered from air."
I don't understand any of this. The only way I could see it work is if the system was activated when the brakes are hit....sort of like an air-brake but with energy recovery integrated.
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Max 2:44PM (2/01/2009)
"a flap that closes at the point where the energy lost under the drag of the ducting is greater than the energy recovered from air.".
I think what's meant is that at a certain speed the drag of air moving under the car is more important than if that air was diverted to a fan inside the car.
But then if you got rid of the fan and routed the air to the end of the car without any obstruction, it would cause even less drag....am I wrong?
Cor van de Water 11:56AM (2/01/2009)
Rory reject KERS (Kinetic Energy Recovery System) based on his faulty understanding, claiming that all KERS available is expensive, while I got it for free with my electric drive system.
Regenerative braking means that you use the same motor and controller that drives the car for slowing it down (reverse the current deliveryto reverse the flow of energy back into the battery).
So I am not sure why a mechanical flap and wind turbine would be not costly to get some recovery of energy during deceleration, but that the already available motor and controller used
for deceleration would cost too much.
I presume that my understanding is just different than Rory's or they use requirements that did
not incorporate KERS in their choice of drivetrain, so now it is difficult to add and they try a
different avenue to get somewhat of the same effect.
However, since it is very hard to capture enough wind to provide a substantial amount of wind
power, this effort is doomed to fail from simple physics.
Most electric drives are 50kW and above. To achieve that power in wind, the estimated surface area (taken from my experience with wind turbines) is almost 100 square meters
(1000 square feet). Where do you find such a frontal area on a car?
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Joeviocoe 9:30PM (2/01/2009)
I think Rory has made a rookie engineering mistake!
I think he has taken set body design which is ascetically beautiful yet aerodynamically broad.
The design reminds me of older style supercars that "needed" the larger body to accommodate the V12 or larger engines.
He had the idea of "wind assisted" when he chose such a broad body so he can design it with these ducts.
If the car was designed with efficiency in mind from the start, it wouldn't look like that and wouldn't need any "range extension". It would be a sleeker design.
So now he has a wide body for the sake of putting in air ducts to recapture energy that wouldn't have been lost if it didn't have that HUGE cross section in the first place!
He does seem to understand that when the car IS NOT BRAKING the drag will ALWAYS exceed the energy captured.
But since he hasn't done a proper cost analysis either, he doesn't know yet that the wind turbines that connect to shafts that connect to generator(s) to recharge the battery will cost more than just buying a better motor controller that simply has that feature included.
There is a reason why the automakers choose KERS.
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Doug 9:35PM (2/01/2009)
How old is this Rory kid? Kinda sounds like a punk.
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Bob Bigglesworth 2:00PM (2/02/2009)
+1 Jim Stansbury
Keep going little dude...Dont let the naysayers get you down..keep challenging the status quo.
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Joeviocoe 12:46AM (2/03/2009)
We are not naysayers, we are skeptics and you need us to keep the BS out of science.
Science without criticism is.... well, Religion.
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luke 4:46PM (2/09/2009)
I agree, science without criticism is religion, but we need to keep our criticism constructive and not personal. Maybe there is a way to recover some energy in the turbulence we leave behind and I support people who are willing to look into apparently blind alleys. A lot of things would not have been discovered without these people.
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Joeviocoe 6:50PM (2/12/2009)
I do agree that it is a good mentality to have but wasting time, money and talent on these project is counter-productive to the whole effort.
It is simply easier and cheaper to reduce turbulence and drag rather than try to recover the energy that is lost from it.
Normal Regenerative Braking is different because you MUST take energy away in order to slow down and stop. That energy is free to put back into a battery. But this design CREATES A WASTE in order to take some of it back.
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