Cool. Since I am going to redesign my safari rack a little before it goes back on I could design a wing to add to the back of the rack when towing the TT. I could make the fastening points a permanent part of the rack for when I am towing. Thanks for the info and updates.

 

I made aluminum brackets that fasten the air deflector directly to the roof rack rails. These brackets clamp to the rails. I made 3 rectangular blocks that slide into the rails. 1/4-20 socket head cap screws thread directly into these blocks.

The 1/4-20 studs that protrude up from the aluminum plates match up to holes in the air deflector. I also added 2 bolt-down locations where 2.5" 1/4-20 bolts are used to further clamp the bottom of the air wing down.

I've had no issues with these brackets since the first time I used them 4 years ago.

Unfortunately, I've lost the AutoCAD drawings I originally created for these brackets. For now, at least I've got some pictures:

 

Thanks a lot for the pictures as well as your time. you do nice work, those are some serious brackets you fabricated.

 

Do you have pictures of this installed ?
I have a 98 Explorer that the VA put an electric mobility device carrier ( three wheel scooter ) on the back, bolted to a class 4 receiver. My hi-way MPG was almost 21 MPG, after this carrier was installed, it dropped to 18 MPG. City MPG has also dropped equally. This carrier, when not in use, folds up vertically to the rear hatch, about 24" away. I recently drove from St. Louis, MO. to Kokomo IN. and I had a large hard shell cargo carrier on the roof. Right away I noticed that my mileage was back up to almost 20 MPG and I was loaded down.
I think the wind is coming along the roof line and dropping down at the rear window and getting caught in between the hatch and the folded up platform. That 24" distance from the hatch and the platform I mentioned. Sorta like pulling a wall behind me.
Removing this scooter carrier isn't an option as it's rated at 500lbs and falls under a DOT regulation. I was told by the installer that this is why it's bolted to the receiver and was advised not to remove it.
I'm trying to put pictures of this in my garage, but they are too large and need to be resized. For now try to visualize a flat platform that goes from below the bumper to about 14" above where the lift handle on the rear window is, jeez, I hope this makes sense.
Any help would be appreciated. I'm a disabled Vet and this MPG is taking a big bite out of my disability check.

Thanks again,

Tom Dimond

 

Hi Tom

I am sorry I do not have any pictures of it and the truck is in storage at my folks, I could take some pics a few days from now when I am out there, for you. I have the same problem on some sites saying I need to re-size that my pics are to large too.
It would probably be easier to e mail them to you. My email is rick700raptor@yahoo.com E mail me your pics and I can reply later in the week and hopefully have some pics for you if you still want them.

I am also a Veteran, no disability though, other that my mind sometimes. LOL

I understand what you mean, that is a very different application, but you may be correct about what the airflow is doing.

Your explorer like my Excursion would require the wing be mounted as far to the rear of the roof as possible. the cheesy straps they come with are a joke and only attach to the rear door opening, which is a bad mounting system and way to far forward on the roof.

I mounted mine to the crossbars of the luggage rack, toward the reward end of the roof. Mine is at a steep angle for air deflection over the roof of my 31" trailer house, your application I think would work better for the wing to be at a shallower angle than mine, I have mine set so the adjustable arms that hold the wing up are straight, your s would work better if the arms were bent so the wing would not in itself cause additional drag for you.