Rear fairing on Prius

To my knowledge, no one else has done this besides myself. I built a composite foam/fiberglass box for this year's Green Grand Prix:



It worked well; mileage in the high 50's to low 60's on the interstate drive out to Watkins Glen, 62.8 mpg in the competition. I'm currently working on lightweight designs for next year--with the tail, cargo rack, and hitch receiver this was nearly 100 lbs hanging off the back of the car.

if you do something, I'd love to see what you come up with.

 

Seems like this could be marketable -- not for the gas mileage alone, but as a storage container that actually improves gas mileage.

 

I don't know...

 

I'd buy one. On the other hand, I'm the guy who already wants to get a trailer hitch just so I can hang a tool chest on it.

For me, the deciding question would be how much the improved wind resistance improved the mileage versus just a chest on a trailer hitch, and does that justify the (presumed) extra cost of buying the aerodynamic version.

 

You might do well to check local and federal laws on externally carried cargo. I seem to recall that we get an allowance for 36" past the rearmost native part of the car in Pennsylvania, and I know there is a long list of specific Federal regulations if the vehicle has commercial plates.

You might also need a high-vis ribbon or similar marking.

Cool idea!

 

I'm thinking about parallel parking, fitting into a garage. Looks, too.

And blocking the lower-rear window: not a great loss, but hey.

 

As far as parking and fit, there's a fair argument for making it collapsible, inflatable or easily removable.

As far as looks go... you know it's a Prius, right?

 

Had I kept it on, I was thinking about gap fillers--but kept running into the issue of hatch access. I sleep in back on road trips (including this Watkins Glen trip), so hatch access was a design goal for me. Next year's version, I think, will be attached to the hatch itself so it moves with the door.

Illinois is 48" before the extension has to be marked with a red flag. I put tail/brake/turn lights on this and reflectors on the sides just to be safe. Some of the other competitors at the GGP complained that the brake lights were too bright.

In case anyone on this thread can't tell already, I don't care if the car is conventionally attractive. Low drag is what looks good to me!

 

Ah yes, that person started several threads on Prius boat tailing and then disappeared. I'm curious if they ever built anything.

Speaking of Ecomodder, this thread contains everything I did up until this spring to further streamline the car. This thread has everything I'm doing to it now for next year's competition, starting with considerable weight reduction.

 

Oh, you may also be interested in this earlier version of a tail, built out of corrugated plastic for a two-week trip to Connecticut last fall:

 

Have you ever looked into modeling this in a virtual wind tunnel? I did something like it once with the custom plane maker in x-plane.

 

Even if the extension has brake lights? That seems odd.

I am going to be adding brake/turn lights to my bike rack since the bikes kinda block the OEM lights. Do you have a part number for the lights you used? I'd like to get something pretty bright. Also, I've been told that the harness hookup is extremely easy, but any pro tips to avoid problems?

Cool, but Version 2.0 = major upgrade!

 

I've actually gone back to school to get an engineering degree, starting this summer, so that's on the horizon! First computer science course this fall.