All ways to get better gas mileage

[Pu241]

There's some published works that indicate small axially-aligned grooves or channels work better for reducing drag on commercial aircraft, than do dimples of any shape.

Like on the wings of the B-58 bomber.
Was supposed to reduce air resistance over the wing.
Think it worked, but we are talking about a supersonic bomber and supersonic airflow.
How well it works in the realm of "flight" the festiva uses I'm not sure.
But, I agree we need to find some way of reducing the coefficent of friction of our vehicals.
Beleive big gains in MPG can be had this way.
Anyone know what the C sub f of the festiva is?
Saw a honda civic that had some exstensive mods made for aerodynamic reasons seems to help mpg wise.
I'll see if I can find pics!

[getnpsi]

ecomodder.com. there are some crazy nerds on there.

[Pu241]

Thanks getnpsi!

I probably would have spend a lot of time finding it again!

Here's what I was refering to above!
Ugly, but I want MPG and if this is what it takes so be it!
Bet we can make a "bob tail" that can be attached around the lip of the hatch and that could be easily attached and removed!
Anyone have access to wind tunnel?
If not, guess we can do test runs with video camera and small smoke "grenades" of some sort.

[XFi]

ecomodder.com. there are some crazy nerds on there.

Absolutely!

[Pu241]

XFi,

This is for you:

http://metrompg.com/posts/xfi-aero-car.htm

[bhazard]

I just scored close to 43 mpg on my second tank with my festy. Almost 5 mpg improvement over my first tank. Still needs front end parts and aligned.

[CharlieZ]

I regularly got 42 mpg on several 44 mile runs a week with my EFI 5 speed. Driven at a fairy steady speed of 55 mph, with a few miles of a 30 mph limit.
I've thought about taping over all the door and window seams then crawl in thru the hatch. The thought of peeling off tape that's seen summer temps is scary. Not too convenient either.

A belly pan might be worth testing.

[litesong]

There's some published works that indicate small axially-aligned grooves or channels work better for reducing drag on commercial aircraft.

Yeah, they are called vortex generators. Usually you like air to flow in smooth layers or laminarly over the wing. But as air flows further back along a wing, the laminar layer becomes thicker & eventually breaks away from the wing in big swirling eddies, that drag badly on airplanes. The implanted vortex generators, placed before the area that causes the big eddies, reinvigorate the boundary layer with little swirls that cause the airflow to follow the wing better, eliminating the big separating eddies.

[Pu241]

I used to know a guy named Big Eddy,he had a brother named Crazy Eddy!:p
Anyone remember Mr. Niven's Co-Dominion as in "The mote in God eye"?

Anyway, I thought the vortex generators were at the end of the wing tips.
Causing the effect you describe. Think "air tabs" used on commerical trucks work similar as well!
They might do us some good as well because of the box shape of the fester.
What Sam.1956 is talking about are "grooves" parallel to the wings leading edge. And, as far as I know, were only used in high performance military aircraft like the B-58 bomber.

FWIW, I got 50.3 mpg on my last tank and expect similar with this tank.
But Big Blue is currently up for some long over mantanence!fftheair:

[litesong]

Anyway, I thought the vortex generators were at the end of the wing tips.

The aero devices at the end of the wings are called winglets & reduce the lateral component of the airflow due to the swept wings & the drag at the very end of the wing called induced drag. In essence, the winglets reduce large swirl eddying vortex drag at the end of the wing, instead of 'generating vortices' as vortex generators do.

[litesong]

Think "air tabs" used on commerical trucks work similar as well!
They might do us some good as well because of the box shape of the fester.

What would work best to kill drag from the Festiva's hatchback would be the curved 'wings' that were seen on some 1960's station wagons. These 'wings' direct air flowing along the top of the car to more easily 'fill' the space directly behind the blunt shaped rear of the station wagon & cause the air to more readily keep the rear window clean. This space behind the station wagon causes lower pressure vacuum that is 'holding' back the car. The air directed into the vacuum by the 'wing' filling the space raises the air pressure reducing the 'hold back' of the vacuum.

[Pu241]

What would work best to kill drag from the Festiva's hatchback .....

"Best" I always like that!

So my longshoreman/aerodynamic engineer creating a structure that tapers from the hatch to a point or near point such as:

http://ecomodder.com/forum/showthread.php/aerocivic-how-drop-your-cd-0-34-0-a-290.html

wont be as good as your "wings"?

And since we are on this topic, do you have a value for the C sub d for the festiva?

[FestYboy]

it's in the range of .41-.43

[Pu241]

it's in the range of .41-.43

Data source?

[gdawgs]

Don't get me wrong I'm not saying you can't use hydrogen as a internal combustion fuel or even that a small amount might actually improve efficieny of combustion.
But you are not going to extract more than about 33 to 35% of the chemical energy in either fuel. We are talking about a heat engine.
Now if you use that hydrogen in a fuel cell that's not a heat engine and you should be seeing about 70% of the chemical energy converted to electricity.
As far as a fuel, hydrogen isn't an ideal IC fuel, as it tends to burn unstabily aka dentonates. I'm not too worried about the water exhaust.
It will be high temperature steam. The exhaust will likey suffer before the engine internal parts.
But, if it was an issue, a ceramic coating would likely solve most of it!
Better route is to use the that electricity to charge a set of batteries for an electric car or better yet use PV to charge those batteries.

Water vapor would not be any more of an issue than it is with burning gas. The vast majority of what's coming out of your tailpipe(assuming it's running properly) is CO2 and water. Hydrogen would work just fine, just like propane and natural gas powered vehicles work fine.