TheSamba.com :: View topic - Started my gas saving technics project

Sat Oct 11, 2008 4:23 pm

thanx TOSU! :D

I will take your advice and try a piece of plexiglass under the front bumper .

For the back, I thought of something using 4 plastic pipes in a cone shape and some plastic liner and see if I can reduce drag.

I also want to try a piece across the back of the roof, slightl ytilted up, kinda what you see on alot of cars now adays...... WHat's your opinion on that. Would the piece across the back of the roof slightly tilted help?

Sat Oct 11, 2008 4:39 pm

NOW you're talking about something that WILL make a difference, and by far, the biggest results would come from modifying the rear end with a bustle. You might get in the neighborhood of 20% with that. That would only be on the highway of course.

but it will look ugly as sin. I have a photo of one somewhere....
there's no way I'd put one on my van even though I KNOW it might add about 20% on the hiway.

Sat Oct 11, 2008 5:51 pm

yah, I was thinking of going to lowes or home depot and see what parts I possibly can work with to make this thing. If I take a long road trip, I would'nt mind getting 20% SAVINGS and having people laugh at my contraption as I'm rolling down the road...... must remember the little red flag on the end of it. :D

Sat Oct 11, 2008 6:58 pm

The piece of plastic on the back tilted up will increase turbulence. On highway cars it is a fashion piece with no benefit as far as I can see. Pretty much any thing you stick out into the airstream will increase turbulence. The object of stramlining is to disturb the laminar flow as little as possible, and to exit the disturbed air as smoothly as possible. Look at pictures of a drop of liquid as it falls, thats pretty much the ideal.
I should mention that we sold the Westie, but this is such a great site that I read the mail here. If anyone objects to my occasional post, I will bail.

Sat Oct 11, 2008 7:35 pm

Greetings tosu.......I for one must object; not for all your valuable postings BUT I cant help objecting because you sold your Westy :cry:
Are you upgrading ? :D .
Either way, stay in touch

Sat Oct 11, 2008 7:53 pm

I've got an '86 7-seat you can have cheap 8)

Here is one ideal:

Buckminster Fuller's Dymaxion car.

Since the trailing edge streamlining would only provide any benefit at considerable speed, how about something inflatable?

Sun Oct 12, 2008 12:18 pm

A boat-tail is ideal, but for a practical vehicle you can get some improvement by simply ending the vehicle abruptly, causing separation of flow and building a dead-air region behind the vehicle that approximates the boat-tail. Look at the rear end of supercars (minus the downforce generators) to get some idea of what I mean.

For the front, the rounder the better, but that has to include the windshield

Sun Oct 12, 2008 1:25 pm

weatherbill wrote: yah, I was thinking of going to lowes or home depot and see what parts I possibly can work with to make this thing. If I take a long road trip, I would'nt mind getting 20% SAVINGS and having people laugh at my contraption as I'm rolling down the road...... must remember the little red flag on the end of it. :D
If this were possible, Home Depot would be the busiest store in the USA.
Old timers had a saying:"If dreams were ponies, all boys would ride."

Al

Mon Oct 13, 2008 7:49 am

Is it WORKING yet?

IS there any fuel savings?

Mon Oct 13, 2008 9:57 am

Hey RBC, this is a bit of a wander off topic. Due to our old bones wanting a bit more comfort, and the length of time for our trips (6 mos this year) we traded the Westie for a small Toyota motor home. Gets almost as good mileage (19mpg). We still love Westies and miss the community and knowledge base. If you see a Toyota MH waving at you its us.
Thanks for asking.

Mon Oct 13, 2008 10:03 am

tosu wrote: Toyota motor home. Gets almost as good mileage (19mpg).

And goes about as fast. :lol:

Mon Oct 13, 2008 11:21 am

On the subject of aerodynamics: there has been some serious research in reducing air drag on tractor trailers. Since an 18 wheeler shares the same basic box shape as our vanagons, any developments there would be applicable. A google search turned up these:

http://web2.clarkson.edu/dor/sure/Sure2000/pdf/pausley.pdf
http://www.eng.auburn.edu/users/cjroy/Conference-Papers/AIAA-2006-3857-913.pdf
http://www.solusinc.com/pdf/SOLUSL&MLicOpp.pdf

Mon Oct 13, 2008 12:42 pm

Appliances are a good resource for smooth flat sheet metal.

A belly pan would help, while obviously one would want to avoid blocking the airflow of the radiator.

Andrew

Mon Oct 13, 2008 9:58 pm

Mightyart, you'd blow my doors off <G>
My experience with aerodynamics leads me to believe that its better to spend your money on tune-ups, good highway tires and beer. A brick is a brick is a brick.
ps we leaving for Mexico Friday or Sat. Best wishes to all.

Tue Oct 14, 2008 1:55 pm

mmm, beer.

Wed Oct 15, 2008 8:31 pm

use your existing lead acid battery to create your reaction here is a little chemistry. and i bet most people didnt even know that seal batteries have a fuel cells Quote: Secondary batteries
Lead–acid Cells
Anode: Sponge metallic lead

Cathode: Lead dioxide (PbO2)

Electrolyte: Dilute mixture of aqueous sulfuric acid

Applications: Motive power in cars, trucks, forklifts, construction equipment, recreational water craft, standby/backup systems

Used mainly for engine batteries, these cells represent over half of all battery sales. Some advantages are their low cost, long life cycle, and ability to withstand mistreatment. They also perform well in high and low temperatures and in high-drain applications. The chemistry lead acid battery half-cell reactions are:

half-reaction V vs SHE
Pb + SO42- —> PbSO4 + 2e- .356
PbO2 + SO42- + 4H+ + 2e- —> PbSO4 + 2H2O 1.685

There are a few problems with this design. If the cell voltages exceed 2.39 V, the water breaks down into hydrogen and oxygen (this so-called gassing voltage is temperature dependent. This requires replacing the cell's water. Also, as the hydrogen and oxygen vent from the cell, too high a concentration of this mixture will cause an explosion. Another problem arising from this system is that fumes from the acid or hydroxide solution may have a corrosive effect on the area surrounding the battery.

These problems are mostly solved by sealed cells, made commercially available in the 1970s. In the case of lead acid cells, the term "valve-regulated cells" is more accurate, because they cannot be sealed completely. If they were, the hydrogen gas would cause the pressure to build up beyond safe limits. Catalytic gas recombiners do a great deal to alleviate this problem. They convert the hydrogen and oxygen back into water, achieving about 85% efficiency at best. Although this doesn't entirely eliminate the hydrogen and oxygen gas, the water lost becomes so insignificant that no refill is needed for the life of the battery. For this reason , these cells are often referred to as maintenance-free batteries. Also, this cell design prevents corrosive fumes from escaping.

These cells have a low cycle life, a quick self discharge, and low energy densities (normally between 30 and 40 Wh/kg). However, with a nominal voltage of 2 V and power densities of up to 600 W/kg, the lead-acid cell is an adequate, if not perfect, design for car batteries.

Thu Oct 16, 2008 3:50 am

wcdennis wrote: On the subject of aerodynamics: there has been some serious research in reducing air drag on tractor trailers. Since an 18 wheeler shares the same basic box shape as our vanagons, any developments there would be applicable. A google search turned up these:

http://web2.clarkson.edu/dor/sure/Sure2000/pdf/pausley.pdf
http://www.eng.auburn.edu/users/cjroy/Conference-Papers/AIAA-2006-3857-913.pdf
http://www.solusinc.com/pdf/SOLUSL&MLicOpp.pdf

The mention of 18 wheeler made me think of Luigi Colani.

Thu Oct 16, 2008 7:35 am

what is the actual difference a good air drag coeffiencent would make in mpg on the vanagon? what is the current air drag coeffiencent of the vanagon? does anyone have any info?

Sun Oct 19, 2008 6:39 pm

what are the results of your test?

here is a link that advertizes hydrogen units
http://www.hydro-fuel-cell.g-review.com/

Tue Feb 10, 2009 11:40 am

Sorry to bring this back up but I just came across an interesting article.

http://www.pressofatlanticcity.com/106/story/396906.html