sepp's second aerocap

[eco_generator]

Nice work!

[winkosmosis]

Originally Posted by sepp

yes there is one with a few nice bolt holes in it, but it doesn't reach out up to the front bumber. there is like a big 2 feet gap.
but actually between the front and rear tires the underside is surprisingly flat and easy to cover. the problem is that gigantic rear differential that is one foot lower than anything else, and thanks to the leaf springs it can do some acrobatic up and down and twisting movements.
the front isn't gonna be easy either, my brain starts overheating as soon as i try to figure how on earth im gonna cover such a complex thing.

I would just ignore the differential. It should be pretty aerodynamic since it's rounded, and the axletubes aren't that big.

But you could direct air under the axle, or to the sides with a V shaped thing, like the front of a boat. A completely flat bottom isn't gonna happen.

[DonR]

The undertray could stop just short of the axle tube swing & cut out a section around the differential. Then make piece of sheet metal that attaches to the diff. housing & extends forward of the cutout in the undertray. You could make teardrop shaped covers for your axle tubes from sheet metal. Then pick up with the undertray just behind the swing of the housing & axles. Turn up the leading edges of the parts so not to catch air.

Mudflaps

Would extending the mudflaps back to the rocker panels in a teardrop fashion help reduce drag as well as protect your truck? You may try a pliable rubber material that would deflect out of the way when met by an offroad obstacle.

Don

[MetroMPG]

Congrats, sepp: your aerocap won the latest Mod of the Month competition!

[FastPlastic]

Originally Posted by DonR

The undertray could stop just short of the axle tube swing & cut out a section around the differential. Then make piece of sheet metal that attaches to the diff. housing & extends forward of the cutout in the undertray. You could make teardrop shaped covers for your axle tubes from sheet metal. Then pick up with the undertray just behind the swing of the housing & axles. Turn up the leading edges of the parts so not to catch air.

Mudflaps

Would extending the mudflaps back to the rocker panels in a teardrop fashion help reduce drag as well as protect your truck? You may try a pliable rubber material that would deflect out of the way when met by an offroad obstacle.

Don

Sounds a little like what I've been working on. Can't say I went to all the work of making the tear drop shape. If you want to take a look at what I've got so far: Jeep Cherokee Aero Mods - Page 2. I found the best place to start is a front skid plate if your truck doesn't already have one.