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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 06-24-2008, 05:24 AM   #1 (permalink)
Hermit
 
Join Date: Mar 2008
Location: The woods
Posts: 42

Aubergine - '94 Ford Ranger 4x4
90 day: 19.14 mpg (US)
Thanks: 0
Thanked 0 Times in 0 Posts
Tuft testing: how to

I'd like to gather how to info here for tuft testing.
  • Tuft testing is an easy way to watch the air flow around your car. I have been using it to test prototype parts for my truck.
  • I used duct tape and cheap yarn from Fred Meyer, which seems to do the trick.
  • Autospeed's advice to keep the strands far enough apart not to touch each other worked well.
  • 4-6" long seems to work well
  • To be continued...

Question: How much wiggle is expected? The ends of my tufts had a 1-2" oscillation, but they generally lined up nicely. Is that too much turbulence or I have I got it right?

__________________
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 06-24-2008, 12:26 PM   #2 (permalink)
Cd
Ultimate Fail
 
Cd's Avatar
 
Join Date: Feb 2008
Location: Austin,Texas
Posts: 3,038
Thanks: 2,261
Thanked 764 Times in 442 Posts
I found that actual yarn has a tendency to stick to itself. I tested both yarn and string side by side and the yarn would twirl around and stick to itself or the yarn above it, ruining the test.

As I have mentioned in other places on this forum, it seems that an easy way to test hard to reach areas such as inside wheelwells and under bumpers would be to purchase a small web cam and run a wire to a laptop within the car.
You could then save a video of the test. The best thing about this method would be that you do not need a chase car.

Any longer than 3" and the yarn seems to flutter due to the turbulence of the yarn itself.
Also it might be a good idea to plan out the layout of the yarn since you don't want the turbulence of a fluttering piece of yarn distorting an area that is smooth.

Edit : I meant any longer than three inches on the length.
__________________
"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; 06-25-2008 at 11:35 AM..
  Reply With Quote
Old 06-24-2008, 02:52 PM   #3 (permalink)
Hermit
 
Join Date: Mar 2008
Location: The woods
Posts: 42

Aubergine - '94 Ford Ranger 4x4
90 day: 19.14 mpg (US)
Thanks: 0
Thanked 0 Times in 0 Posts
So if I cut off the part that was fluttering I may get clearer results? I put all the pieces far enough apart not to stick to other pieces.
__________________
  Reply With Quote
Old 06-24-2008, 06:58 PM   #4 (permalink)
EcoModding Lurker
 
Join Date: Jun 2008
Location: Stoughton, WI
Posts: 55

Polymer - '89 Honda Civic Hatch Std 4 speed
90 day: 51.49 mpg (US)

Woodstock - '69 MG Midget 1275

Nekobus - '06 Scion xB
Thanks: 0
Thanked 2 Times in 2 Posts
Sailors sometimes use audio tape instead of yarn for "telltales" (to see if the sail is sheeted in correctly).
Might be worth a try.
__________________
  Reply With Quote
Old 06-25-2008, 11:40 AM   #5 (permalink)
Cd
Ultimate Fail
 
Cd's Avatar
 
Join Date: Feb 2008
Location: Austin,Texas
Posts: 3,038
Thanks: 2,261
Thanked 764 Times in 442 Posts
Quote:
Originally Posted by millenniumtree View Post
Sailors sometimes use audio tape instead of yarn for "telltales" (to see if the sail is sheeted in correctly).
Might be worth a try.

That seems like a really clever idea. Thank you for suggesting that - I never even thought of that.

Since the audio tape lies flush with the curve of the body, it would seem like there would be less far less turbulence caused by it versus yarn.
__________________
"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
  Reply With Quote
Old 06-25-2008, 11:43 AM   #6 (permalink)
Cd
Ultimate Fail
 
Cd's Avatar
 
Join Date: Feb 2008
Location: Austin,Texas
Posts: 3,038
Thanks: 2,261
Thanked 764 Times in 442 Posts
Quote:
Originally Posted by nwbabybronco View Post
So if I cut off the part that was fluttering I may get clearer results? I put all the pieces far enough apart not to stick to other pieces.
It seemed to work for me .
Better to ask the experts on the matter.
I also edited the previous post. Any longer than three inches and I started to see fluttering.

__________________
"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
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Video: tuft testing (rear) 1993 Ford Mustang notchback MetroMPG Aerodynamics 12 02-05-2011 09:40 AM
tuft testing, vortex generators, and God's own wind tunnel jim-frank Aerodynamics 10 06-27-2009 02:48 PM
tuft testing on 93 Sentra back window jim-frank Aerodynamics 5 06-16-2008 04:59 PM
an interesting point of view (wool tuft testing video) fabrio. EcoModding Central 10 04-02-2008 04:16 AM
Video: someone DIY tuft testing a Volvo MetroMPG Aerodynamics 4 12-29-2007 02:07 AM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com