A Wind Fairing for the Travato Roof Rack

[thefitrv]

Built one last weekend. More details on our site. Probably about $80 in parts. Making the pattern fit properly to the roof was the hardest part.

So far, so good - no weird noise, fewer bugs stuck up there. Too soon to tell on the gas mileage, but I really doubt it's going to be worse.

Cheers!

[Scottbaldassari]

Very nice...
With engineering skills like that, you should just design your own RV....
...erhh... wait... you kinda did.
Sumo Springs article on your site also very helpful.
Thanks.

[wincrasher]

From my experience the roof rack costs you 1 mpg. I think it is not so much the drag, but that it creates alot of turbulence. This should help alot.

[wincrasher]

James, I wonder if some kind of spoiler on the rear leading edge would do any good. You know, like the ones you see on minivans like the Odyssey or Sienna. They extend the roofline a little and direct the air at the back of the van. Could make a big difference.

[eric1514]

Originally Posted by wincrasher

James, I wonder if some kind of spoiler on the rear leading edge would do any good. You know, like the ones you see on minivans like the Odyssey or Sienna. They extend the roofline a little and direct the air at the back of the van. Could make a big difference.

I thought those were just to keep the rear windows clean.

Eric

[wincrasher]

The slab back end on the Promaster is making huge drag. Anything that could break that up could show some real mileage improvements. Look what they are doing on the big trucks. I'm not suggesting anything anywhere near that radical. But obviously it has some effect.

[thefitrv]

Well, the big slab back end does create an area of negative pressure. Even the start, or the "suggestion" of an airfoil shape will have a positive effect. They're doing this sort of thing with bicycle frames these days. The tubes on my Time Trial bike are an abbreviated airfoil shape.

A lot of the spoilers we see on cars are purely decorative. Some of them are somewhat functional, and some of them are downright ridiculous. It always cracks me up when I see a front wheel drive car with a giant spoiler on the rear wheels (a-la formula 1 cars). But I'm getting off-topic...

I honestly hadn't looked at doing anything to the back end of the Travato, but maybe I will. I don't think there's a nice, convenient way to attach anything like there is up front. And any spoiler would have to clear the ladder, the vent stack, and potentially mounted (mountain) bikes. Still, it's worth a look.

I once toyed with the idea of adding those "airtabs" to our Sprinter. (Different from a solid spoiler though.) I don't think I'd want them on the sides, but maybe on the roof? I'll put it in my "things to think about" doc.

[wincrasher]

Sounds like a great reason to get a 3d printer....

[eric1514]

James,

Can you elaborate on which fairings you tried and why they didn't work for you?

Eric

[thefitrv]

I have a Yakima rack on my Subaru, with a pretty extensive collection of mounting hardware. I couldn't get any of the mounting hardware to play nice with the Fiamma rack, so I didn't pursue Yakima any further.

Thule was the only manufacturer I found with a stock fairing greater than 50 inches. The space between the uprights is about 54 inches, and Thule makes a 52 inch rack. I ordered the 870XT. It didn't quite fit the Fiamma bar either, but I thought about trying to make some adapter. Eventually I realized that the Thule rack was going to cover up the gps/Sirius antenna, and so I just sent it back.

I even had some of the Thule reps come over to the Travato on display at the Outdoor Retailer show. We climbed on the roof and they eventually concluded it just wouldn't work.

Didn't try any fairings from smaller companies - but I also didn't see any that were greater than 50 inches wide.

Eventually, I realized it would be just as easy to make a fairing myself as adapting a commercial one to work. Once I had all the stuff, I pretty much got it done in a day.