Vortex generators?
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From: Montana
Vortex generators?
Anyone had any experience with vortex generators or other drag reducing techniques on their van? What did they do to your mileage?
Airtabs (http://www.airtab.com/) is one company I'm thinking about.
Airtabs (http://www.airtab.com/) is one company I'm thinking about.
More Turbo
Joined: Jun 2004
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From: Sweden
Huh, at first I thought this was going to be another question about air intake "vortex" spinners (fraud).
It's not going to kill drag, but they only claim 4%-8% which is surprisingly plausible for a fuel saving claim. I'm used to everybody selling fuel devices to claim 20%.
That would be tough to say. I've long ago concluded that people in general don't seem to be able to reliably measure changes in fuel consumption within even 15%. It's not that I don't believe gains are possible, but people saying they had such-and-such results are likely meaningless. Unfortunately the only guys doing wind tunnel tests are always tied to the company itself...
I'd kind of want to hook up the GPS to a logger, get up to 70 mph, put the vehicle in Neutral and see how fast drag slows the vehicle down- removing the engine and fuel consumption measuring methods from the equation is quite desirable! It'd have to be on the same terrain though, same wind conditions, and same air temp. Then do the same with the generators. Unfortunately these things can only be put on once, and would be really tough to take off.
It's not going to kill drag, but they only claim 4%-8% which is surprisingly plausible for a fuel saving claim. I'm used to everybody selling fuel devices to claim 20%.
That would be tough to say. I've long ago concluded that people in general don't seem to be able to reliably measure changes in fuel consumption within even 15%. It's not that I don't believe gains are possible, but people saying they had such-and-such results are likely meaningless. Unfortunately the only guys doing wind tunnel tests are always tied to the company itself...
I'd kind of want to hook up the GPS to a logger, get up to 70 mph, put the vehicle in Neutral and see how fast drag slows the vehicle down- removing the engine and fuel consumption measuring methods from the equation is quite desirable! It'd have to be on the same terrain though, same wind conditions, and same air temp. Then do the same with the generators. Unfortunately these things can only be put on once, and would be really tough to take off.
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From: Montana
Drag Reduction (better topic)
Wrong choice of words, would edit the thread posting but that seems to be disabled for my account.
Generally interested in what people have done to reduce the profile of our boxy vans. Objective results from what has been attempted would be great and if not available anecdotal results would also be interesting.
I suspect that pulling in my monster mirrors, not carrying the boat on top and driving something slower than as fast as it will go are all cheaper and more effective than putting on some vortex generators.
Generally interested in what people have done to reduce the profile of our boxy vans. Objective results from what has been attempted would be great and if not available anecdotal results would also be interesting.
I suspect that pulling in my monster mirrors, not carrying the boat on top and driving something slower than as fast as it will go are all cheaper and more effective than putting on some vortex generators.
More Turbo
Joined: Jun 2004
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From: Sweden
Yeah the aero on a van are pretty horrific. Big mirrors and a boat are pretty significant penalties that might have a noticible benefit to correct.
What would really do it would be a large fairing on the front and rear. That would make it rather difficult to park, though once I wondered if a removable one used to travel cross country wouldn't be justifiable. Also cutting off the airflow to the radiator would be quite a problem.
Making use of the available space is one of the reasons mfgs don't do this. The van is designed to be as long as it can be and still use normal parking, they can then either stretch the nose out like a minivan to get good aero OR maximise the cargo space like a snub nose cargo van.
There are guys doing their own EV conversions with sedans, and they're so critical they don't just want door handles inset into the door, but they have noticed gains from taping over the gaps and juts in the body panels. Small gains, but they're trying to be extremist to get a few more miles of battery range.
What would really do it would be a large fairing on the front and rear. That would make it rather difficult to park, though once I wondered if a removable one used to travel cross country wouldn't be justifiable. Also cutting off the airflow to the radiator would be quite a problem.
Making use of the available space is one of the reasons mfgs don't do this. The van is designed to be as long as it can be and still use normal parking, they can then either stretch the nose out like a minivan to get good aero OR maximise the cargo space like a snub nose cargo van.
There are guys doing their own EV conversions with sedans, and they're so critical they don't just want door handles inset into the door, but they have noticed gains from taping over the gaps and juts in the body panels. Small gains, but they're trying to be extremist to get a few more miles of battery range.
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A collapsable fairing (for the rear) might be the ticket. I understand that there are some available for the semis. Unfortunately, they haven't been welcomed by drivers due to their appearance, something like "duck butt?"
My boat drag is now just an expectation, as I just got my van and haven't mounted a rack. That will be a challenging project as the van has a "camper" roof on it and stands close to 8.5 feet tall.
My boat drag is now just an expectation, as I just got my van and haven't mounted a rack. That will be a challenging project as the van has a "camper" roof on it and stands close to 8.5 feet tall.
More Turbo
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From: Sweden
Duck butt... hehehe.
It can't be made of something flexible, because the wind load will just pull it where it was going to go anyways. In theory something inflated with enough PSI could hold a favorable shape, but complex shapes can be difficult to achieve with inflatables.
Ideally a front and rear fairing reaching towards the ground, like a bullet trail, would be ideal. The windshield is still at way too flat of an angle forward. There are concerns that it can affect the vehicle's handling, or even catch air underneath and lift the vehicle. If they're low to the ground, there's a chance they could strike when going over features on the driving surface that are not flat or when accelerating, braking, or under varying cargo weight on board. Basically things that nose the vehicle up or down.
It would definitely get some laughs, this is the kind of thing you want to do as part of a college project to gain attention.
It can't be made of something flexible, because the wind load will just pull it where it was going to go anyways. In theory something inflated with enough PSI could hold a favorable shape, but complex shapes can be difficult to achieve with inflatables.
Ideally a front and rear fairing reaching towards the ground, like a bullet trail, would be ideal. The windshield is still at way too flat of an angle forward. There are concerns that it can affect the vehicle's handling, or even catch air underneath and lift the vehicle. If they're low to the ground, there's a chance they could strike when going over features on the driving surface that are not flat or when accelerating, braking, or under varying cargo weight on board. Basically things that nose the vehicle up or down.
It would definitely get some laughs, this is the kind of thing you want to do as part of a college project to gain attention.
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Secret Agent 069
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