Go Back   EcoModder Forum > EcoModding > Aerodynamics
Register Now
 Register Now

Now available from EcoModder: ScanGauge II fuel economy gauge.  Click for details.  

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 07-01-2011, 09:10 PM   #1 (permalink)
Master EcoModder
 
basjoos's Avatar
 
Join Date: Dec 2007
Location: Upstate SC
Posts: 740

Aerocivic - '92 Civic CX
Last 3: 70.54 mpg (US)

AerocivicLB - '92 Civic CX
Team Honda
90 day: 70.97 mpg (US)
Thanks: 1
Thanked 147 Times in 77 Posts
Most aerodynamic cargo box?

When you look at most roof top cargo boxes (Yakima, Thule, etc.), most of them are as un-aerodynamic as the vehicles carrying them and would present lower drag if they were mounted backwards. They tend to be wedge shaped with a rounded tapering front end, a broad flat back end, and don't appear to take into consideration the rising air flow coming off the windshield. In college, I used to car top a kayak and use it as a cargo box. It was more aerodynamic than any of the cargo boxes that I've seen on the road. How would you design a cargo box to meld in with the roof line of a car to produce a minimum of additional drag?


(Support Ecomodder.com & get rid of these annoying ads!)      
 
  Reply With Quote
Old 07-01-2011, 09:59 PM   #2 (permalink)
Master EcoModder
 
kach22i's Avatar
 
Join Date: Jul 2011
Location: Ann Arbor, Michigan
Posts: 613
Thanks: 3
Thanked 80 Times in 61 Posts
Sounds like you have given this topic some thought.

A longer body is by it's proportional nature more aerodynamic than a comparable shorter body. Therefore not only would a longer carrier body be an advantage, but if it actually worked to lengthen the vehicle body there would be a total advantage.

Think of those trailing edge roof spoilers on hatchbacks, what they are doing is making the car body longer, right?

A roof top carrier which cantilevered over the rear roof edge might be the ticket.
__________________
George
Architect, Artist and Designer of Objects

1977 Porsche 911s Targa
1998 Chevy S-10 Pick-Up truck
1989 Scat II HP Hovercraft

Chin Spoiler:
http://forums.pelicanparts.com/off-t...effective.html

Rear Spoiler Pick Up Truck
http://forums.pelicanparts.com/off-t...xperiment.html

Roof Wing
http://ecomodder.com/forum/showthrea...1-a-19525.html
  Reply With Quote
Old 07-02-2011, 12:27 AM   #3 (permalink)
ooo ooo ooo ah ah ah
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 7,357

Blue - '93 Tempo
Last 3: 27.29 mpg (US)

ShWing! - '82 gold wing Interstate
90 day: 33.65 mpg (US)

F150 - '94 F150 XLT
90 day: 18.5 mpg (US)

Sport Coupe - '92 Tempo GL
Last 3: 69.62 mpg (US)

Moon Unit - '98 Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 636
Thanked 848 Times in 591 Posts
I would hang it off the back instead of up top.
__________________


  Reply With Quote
Old 07-02-2011, 10:25 AM   #4 (permalink)
Master EcoModder
 
kach22i's Avatar
 
Join Date: Jul 2011
Location: Ann Arbor, Michigan
Posts: 613
Thanks: 3
Thanked 80 Times in 61 Posts
Quote:
Originally Posted by Frank Lee View Post
I would hang it off the back instead of up top.
It would be easier to get to that way. And could lengthen the vehicle body aerodynamically if done right.
__________________
George
Architect, Artist and Designer of Objects

1977 Porsche 911s Targa
1998 Chevy S-10 Pick-Up truck
1989 Scat II HP Hovercraft

Chin Spoiler:
http://forums.pelicanparts.com/off-t...effective.html

Rear Spoiler Pick Up Truck
http://forums.pelicanparts.com/off-t...xperiment.html

Roof Wing
http://ecomodder.com/forum/showthrea...1-a-19525.html
  Reply With Quote
Old 07-02-2011, 11:18 AM   #5 (permalink)
Tenderfoot
 
ChazInMT's Avatar
 
Join Date: Jan 2010
Location: Bozeman Montana
Posts: 437

MagMetalCivic - '04 Civic EX
90 day: 37.18 mpg (US)
Thanks: 127
Thanked 169 Times in 88 Posts
Funny thing, I always notice these roof cargo boxes now for this reason....They're all put on backwards!! I swear I’ll crap my pants if I ever see someone who has it mounted tapered end back. The tapered end is invariably the front of the box, and unless you've been living under a rock, (or you’re not a frequent visitor to Ecomodder.com) we all know that the taper should be in the back. I wonder if the weather seal is different on the front & back which is the reason you never see them turned around by someone who would know better. Some boxes have a flat back, but others have a perfect aero shape, if mounted the other way. I think they should hang off the back as far as structurally possible as well.
  Reply With Quote
Old 07-02-2011, 11:24 AM   #6 (permalink)
EcoModding Lurker
 
Join Date: Aug 2008
Location: Canada
Posts: 81
Thanks: 1
Thanked 16 Times in 6 Posts
Quote:
Originally Posted by Frank Lee View Post
I would hang it off the back instead of up top.
Darn it, you beat me to it.
Hitch Cargo Carriers from Proline
  Reply With Quote
Old 07-02-2011, 04:12 PM   #7 (permalink)
EcoModding Apprentice
 
bondo's Avatar
 
Join Date: Jan 2008
Location: Arkansas
Posts: 239
Thanks: 46
Thanked 118 Times in 49 Posts
Quote:
Originally Posted by Frank Lee View Post
I would hang it off the back instead of up top.
Correct.
Attached Images
File Type: jpg hitch mount 3.jpg (81.3 KB, 213 views)
  Reply With Quote
The Following 6 Users Say Thank You to bondo For This Useful Post:
Cd (07-02-2011), cfg83 (07-02-2011), jsatter (07-05-2011), PaleMelanesian (07-07-2011), Piwoslaw (07-03-2011), t vago (07-05-2011)
Old 07-02-2011, 04:24 PM   #8 (permalink)
Pokémoderator
 
cfg83's Avatar
 
Join Date: Dec 2007
Location: Southern California
Posts: 5,724

1999 Saturn SW2 - '99 SW2 Wagon
Team Saturn
90 day: 43.05 mpg (US)
Thanks: 385
Thanked 459 Times in 315 Posts
bondo -

Is that another prototype for commercialization?

CarloSW2
__________________

What's your EPA MPG? Go Here and find out!
American Solar Energy Society
  Reply With Quote
Old 07-02-2011, 04:46 PM   #9 (permalink)
EcoModding Apprentice
 
bondo's Avatar
 
Join Date: Jan 2008
Location: Arkansas
Posts: 239
Thanks: 46
Thanked 118 Times in 49 Posts
Quote:
Originally Posted by cfg83 View Post
bondo -

Is that another prototype for commercialization?

CarloSW2
We hope so Carlos. It took King C. Gillette 17 years to get his new safety razor accepted and profit from the sale of the razors. You have to bear this in mind whenever working on getting a product to market.

I am getting some very good numbers with this new cargo box and another type which mounts on the open tailgate. R&D doesn't pay much but you have to do it.

Have a good 4th,

Bondo
  Reply With Quote
Old 07-02-2011, 07:47 PM   #10 (permalink)
Cd
Ultimate Fail
 
Cd's Avatar
 
Join Date: Feb 2008
Location: Austin,Texas
Posts: 1,924
Thanks: 750
Thanked 135 Times in 84 Posts
Quote:
Originally Posted by bondo View Post
Correct.
Bondo, your designs look awesome !

I have noticed the same thing about roof top cargo carriers for years. They are all backwards.

Even the manufacturers show the carriers mounted the wrong way. Its the old idea that pointy ends are better than blunt ends.



(Support Ecomodder.com & get rid of these annoying ads!)      
 
__________________
"You don't fail until you give up. You learn, and move on." - Christ

" Hypermiling is not going slow, it's driving with more intelligence." - UFO

Last edited by Cd; 07-02-2011 at 07:57 PM..
  Reply With Quote
Reply  Post New Thread

Thread Tools





Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2012, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com