Video: Illustrating the Vast Importance of Aerodynamics (open hatchback experiment)

[MetroMPG]

SuperMID. (Ask SVOboy about them.)

[Piwoslaw]

I understand that the hatch in Peakster's test was wide open, as in almost vertical. Has anyone tried a test with the hatch halfway closed? If the hatch was horizontal or sloping slightly downward, then would it act like a boattail? Maybe opening the hatch only slightly (and keeping it there with a string) could improve FE?

[thefirebuilds]

Originally Posted by DifferentPointofView

I wonder... I'm getting a wind noise from my drivers side door that indicates that air is leaking into the cabin. Would this hamper mpg by far? I'm guessing it's just the 13 year old rubber seals that I'm trying to fix by adding some lube between it for a better seal, but didn't have really much at all to get the job done. Just wondering, It's difficult to get good Cd in a jeep, but with the roads here it'd be a miracle to make it through with a metro.

I wonder the same thing with mine, the door was impacted and its bent out maybe 1/2" or so, and it makes the windy noise pretty loudly. i tried to fix the door with a hammer but it needs a greater commitment of time than that so I may replace it.

[MetroMPG]

Originally Posted by Piwoslaw

I understand that the hatch in Peakster's test was wide open, as in almost vertical. Has anyone tried a test with the hatch halfway closed? If the hatch was horizontal or sloping slightly downward, then would it act like a boattail? Maybe opening the hatch only slightly (and keeping it there with a string) could improve FE?

That idea could work, depending on the car, but not on the Metro.

The top portion of the hatch forms the last 6 inches or so of the roof, so opening it even part way raises up a drag-inducing "spoiler" at the end of the roof line that also increases projected area. That would negate any benefit from trying to extend/taper the roof line with the "rear" portion of the hatch.

It would have to be just the right kind of hatch design to use as a basis for tapering the rear of the vehicle.

[Sandy]

Not only a hatch, but a trunk too.
On a return trip from Maine to NH,
I had to carry a box in the trunk, that required the trunk to be open,
but held down by a bungy.
Wow,
I felt like I was pushing a sail.
This was before I had the scangauge so there aren't 'real' numbers,
but the little Civic had to be forced to driven down hills.
That trunk lid ruined the aero of that car.

[red91sit]

Originally Posted by Sandy

Not only a hatch, but a trunk too.
On a return trip from Maine to NH,
I had to carry a box in the trunk, that required the trunk to be open,
but held down by a bungy.
Wow,
I felt like I was pushing a sail.
This was before I had the scangauge so there aren't 'real' numbers,
but the little Civic had to be forced to driven down hills.
That trunk lid ruined the aero of that car.

When I brought my scooter to college, My Contour topped out at 75 mph (the trunk was wide open, and the front wheel was hanging out in the wind)

[gascort]

I removed my airdam last week for aome a-b-a testing, and so far I'm really noticing my low speed coasts are hit bad - they're the ones where I know exactly how far to coast, and showing up 20m short of a red light I coast to from 35 mph really seems like a lot.

I've noticed the expected hit on the highway too, but it wasn't as shocking to me. After re-reading this thread... now that makes sense!

[racerc2000]

lol if I didnt have the rear spoiler opening my rear glass may help alil. but having the spoiler with it open the spoiler sits at almost a perfect 90 degrees. so it works like an air brake

really doesnt help when im also carrying 20+ sheets of 4X8 materials ply sheetrock etc

luckily with many low loads I can leave my tailgate down and close my glass that shouldnt hamper EF much? I hope