Time to work on Ugly
 

After the last couple of outings Ugly came back a bit worse for wear. So its time to do some major work, mostly body and frame this time.

So the plan aside from repairs it to build a custom roll cage and what I'm thinking is to have the front of the cage (the two bars right behind the windshield continue up past the top of the windshield then curve back and slope gently down to just behind the front seats. The intent even though it increases my frontal area is to reduce the low pressure area behind the windshield in hopes to at least improve highway stability.

After the front seats it will continue to slope down but also in so that by the time it gets to the back of the Jeep it will be even with the outside of the cargo box. I would apreciate any thoughts.

http://ecomodder.com/forum/member-th...e3900-side.png

http://ecomodder.com/forum/member-th...e3899-diag.png

These pictures are pretty close to what I am thinking.

Have you given any thought on doing an inspired take-off of the 2002 Jeep Compass Concept?

Jeep Compass Concept wallpaper # 04 of 22, Front Angle, MY 2002, 800x600
http://www.netcarshow.com/jeep/2002-compass_concept/
http://i184.photobucket.com/albums/x...ncept_EDIT.jpg

I hate the Jeep Compass, but liked the Concept Compass shown above.

Do your roof as proposed, angle the front grille a bit and you would have something interesting.

I think the wheel flares will be the big aero-killer. At least on my truck they are.

EDIT: ...............like this
http://s184.photobucket.com/albums/x...ransportation/
http://i184.photobucket.com/albums/x...Jeep-Study.jpg

right now I am doing just the cage and the removable parts of the body, later on I do plan on working on the nose and the wheel wells.

No matter what I do it has to perform well while off-road.

Interior is almost gutted, having to cut 25 year old rusted torx bolts to get the stock roll bar out. Man I hate those torx bolts.

Even though things came up I am making progress.

The body is off, and am almost done fixing some of the drivetrain issues while I can get to them easier.

I am having to rebuild the body mounts which isn't much of a surprise as the old AMC Jeep body mounts are notoriously weak.

What has been a surprise is that the members of the off road club are encouraging the aero mods for both stability and better FE and offering to help get it done.

that's cool, hope it goes well

IMHO the curve above the windshield is too sharp and there isn't enough curve behind that. Since you say you're putting a curve in the actual roll cage itself, why not have it curve all the way to the back.http://i.imgur.com/2rhnY.jpg

Else you could use straight tubes and add fins or ribs on the top to get the curve.

And chop the windshield.

How long of a boat tail can you make without affecting the departure angle? ;)

I don't have acess to the right type of bender to make long curves.

I was thinking of building a boat tail that would encase the spare and add some storage, the bottom of which would be a skid plate to slide off of the rocks.

Brace a 20' tube against 2 trees 15' apart and throw you winch cable around the middle. When it pulls through you'll have more curve in the middle. Cut it in half and the middle of each piece goes to the front. :)

I would have to bury 2 poles, we are a bit short on decent sized trees here. The curve would be stronger, but I have some doubts as to the ease of making it come together.

I wasn't completely serious. Especially the part about pulling completely through. Ouch!

Get someone to weld up some smaller segments that gradually change angle. When you get the top and sides done the rest should be relatively easy.

If you're going to do it, do it right!

The main purpose of the cage is to keep me from getting hurt/killed for if/when I roll it over. All it would take is one bad weld and the cage fails which could end badly for anyone inside.

What I should be able to do is a slight bend every 12" or so. That would approximate a curve pretty closely.

There ya go.

How are you doing the short bends? Heat? Mandrel bends?

I have a 12 ton press for bending tubing up to~1 1/2". It has two upper rollers and an adjustable lower die. I don't know that it's adequate for roll bar tubing. If it had a lower roller you could pull the tube back and forth like sheet metal on an English wheel to make longer curves.

Maybe improvise the rollers, drill holes in the ends of a piece of tubing for winch cables, and have a couple for 4x4 buddies stand off on each side and pull it back and forth with their winches?

"I didn't know what I was doing, but that never stopped me before."

1 3/4 DOM .12 wall tubing

I have access to a mandrel tubing bender and notcher.

We got the main 3 hoops bent up this weekend with the front (A hoop) tacked in. Talk about a workout!!! apporx 18:1 mechanical advantage (18 ninty degree strokes on the handle = 90 degrees of bend) with a 3' bar still took quite a lot of effort to move.

I have allmost all of the body mounts rebuilt and beefed up and the new body frame is cut and essentially welded in.

Its looking like it will come out pretty nice so far.

pics, or it didn't happen. :)

http://ecomodder.com/forum/member-th...8-p1010662.jpg

The new structure for the body mounts, and what the roll cage is getting attached to.

http://ecomodder.com/forum/member-th...7-p1010663.jpg

The front roll bar fits nice and snug to the winshield frame, which is not there. The middle roll bar still needs trimming and the body needs some trimming to get it to fit without taking up any additional space.

http://ecomodder.com/forum/member-th...6-p1010664.jpg

The rear roll bar leaning against the back, it also needs trimming to fit. It tapers in for a partial boat tail

The bottom rear box tube isn't in place yet because I will be welding the roll bar to it then attaching it to the body so I can get the welder to it.

Well, there you are. It took me a moment to sort out that bottom view, w/ the rear wheel-wells on the left. So that rectangular tube "C" shape is all new?

Are you going to tie the rear bar and box section forward to the "C" part?

All new, in the middle of the C (top and bottom of the picture) will get 2 more body mounts to replace the cracked and rusted ones there. The sections under the door frames will also double as rock sliders.

There isn't enough room to do it with the box tube, but I am connecting the top of the hoops, then between the middle and back hoop at the top of the tub I will connect them. That should strengthen and stiffen up the body by quite a bit.

Along the inside top corner of the wheel-well then. Sounds like it could work.

I'll post some pictures when I next get a chance, but the body is back on the frame.
I still don't have the bracing tubes in.
I sprayed a couple of layers of Krylon white underneith.
Seats and the lap portion of the harness in.

Unfortunetly I broke the gas tank while trying to get it ready for an event last weekend (so I didn't get to go). Went to bleed the brakes at 11pm friday night, and layed in a puddle of gas.
We have started building a new 12 gallon 3/16 steel gas tank and the bottom is going to be 3/8 with internal ribs.

It will be a little heavier than the stock 16 gallon but hang down only half as far. The rear axle hangs down lower than the new tank instead of the tank.

Its been awhile since I updated this thread, but we finished the cage, 12 gallon custom fuel tank, and a complete rewire as well as paint.

http://ecomodder.com/forum/member-th...-jeep-rear.jpg

http://ecomodder.com/forum/member-th...-jeep-side.jpg

There is still a lot of work to do but we took it out yesterday and averaged 1 gallon per hour on some pretty rough trails.

We still need to finish the windshield, roof skin, spare tire rack and tail gate... and more.

triangulation
 

Don't smack me for being a smarty-pants,but it would be good to see some major gussets or triangulated tubing members to stiffen up the cage.It's prone to buckling if you ever invert it.
A neighbor 'lost it' pulling telephone poles on a flatbed trailer and ended up on his roof.
The sturdy,and well-triangulated bed rack saved his bacon,and his crew.;)

I was actually thinking of adding in some gussets just to make sure it was strong enough.

So I took it on a trip 160 miles one way and got about 16mpg which is an improvement of approx 2mpg, probably largely because the windshield/sail is still not installed. I couldn't get a good reading from one of the fuel pumps, because it broke down on me, and I had to fill up some place else.

edit: that was also with about 500lbs of camping gear in the back. Typical mpg was in the 12-14mpg range

I did notice something on the drive back, that made me wonder.

When big trucks were passing the other direction the turbulance would often persist much longer than expected, kind of like it cause the flow over the front of the Jeep to cause more turbulance. It could be that the combination of driving somethig that was still an aero-dyanamic disasterpiece though a section of turbulance would cause it to drag the turbulance with it, but it made me wonder if turbulant air would cause even an aero design to create more turbulance, or for that turbulance to persist after the vehicle has cleared the turbulant section.

turbulence
 

The turbulence behind a big rig extends for many hundreds of feet behind.What we 'pick up' from them would be determined by local weather conditions,wind,speed,direction,as oriented with the roadway and our position in relation to them.
Head on,you'd get the bow wave,then suction as it goes by,then wacked by the wake,with some nice buffeting.
Since low drag cars are governed by a laminar inviscid outerflow environment,driving one through a region of major turbulence would completely alter the flow.All bets would be off the table.
You may have experienced the pressure pulsations of cast off vortices within the wake of an 18-wheeler.This is the major league of eddies.

It would definetly begin to pulsate, but with them going 65ish, and me going 60 in the opposite direction we would get close a mile appart by the time it would smooth out.

distance
 

Over at the full-boat-tail trailer thread there is a table showing buses and cars drafting and you can see the effect between them at really large separation distances going in the same direction.The distance gives an indication of how far way the air remains disturbed.
This sort of thing is good for geese flying in formation.

It didn't last long before something else broke... rear ring gear on the AMC20 started spitting teeth because of a loose bolt.

Its almost fixed, installing front and rear Dana 44's with 4.56 gears 5th gear at 75 should turn 2500 rpm on the future planned 35" tires. Previously with the 3.54 gears on 31" tires I couldn't hardly use 5th gear.

We also put on a tarp as a shade the day it broke, at 40 mph the tarp wasn't slapping or being pulled off so I think the shape works pretty good, at least with the windshield still off.

Well an update on Ugly, Shortly after we did the tarp shade we blew the rear end out, didn't even make it to the trail. So as is often said when something brakes, its an opportunity for an upgrade.

Dana 44's front and rear (donated from a late 80's Waggoner) with selectable lockers
4.56:1 gears (2500 rpm at 75 with 35" tall tires) Only have 31"'s right now.
New bearings/seals all around.


At the very least I will be able to use 5th gear again.

Well its back on (or off) the road again, wound up putting a rear axle out of a Honda Passport, it fit better and came with disk brakes. I wont be able to go fast enough for the freeway with the new gears, until I get the bigger tires.