×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Shelby fastback aerodynamics

Shelby fastback aerodynamics

Shelby fastback aerodynamics

(OP)
Greetings all,
Can someone explain the aerodynamics of the Shelby GT350 Mustang's fastback window treatment?  I've been looking at them at the vintage races and wondering.
They use lexan rear windows with the front most edge dropped down into the interior of the car.  Clearly shaped to exhaust air from the interior into the airstream over the roof.  I'm told it provided a phenomenal downforce but I don't understand the dynamics.  Can anyone provide an answer or point me to a Link?
Thanx in advance, Steve Smith

RE: Shelby fastback aerodynamics

If there's enough flow out through that gap the airflow over the roofline won't get dragged down as far as it passes over the rear window, and the upside-down diffuser-shape won't be as effective.  I'd guess that the actuaL result was mainly one of less aero lift rather than the creation of actual downforce.

Norm

RE: Shelby fastback aerodynamics

A little rule I always apply to peoples claims of down force from aero devices is to look at the strength of the device, especially the attachment points.

The down force can't be greater than the strength of the device, that is if the device never fails in use.

Regards
pat   pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: Shelby fastback aerodynamics

(OP)
Excellent comments both.  I think Norm has the explanation and Pat has pointed out a missed but obvious point.  Thanx to both.  Steve

RE: Shelby fastback aerodynamics

It might be the same effect as boundary layer interrupt slots on airplane wings that vent a little just in front of the area of boundary layer separation. Disturbing that enough to keep the airflow attached rather than having it curl off and create lift.

 Same as properly placed riblets, dimple tape, etc.

(did I get that right?)

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources