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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 06-06-2009, 04:18 PM   This thread is in the EcoModder Project Library | #1 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 8,277
Thanks: 10,029
Thanked 4,316 Times in 2,389 Posts
Phil Knox's aero-modded 1970 VW van

Hello all.There has been some interest in streamlining vans,and especially some interest in van boat tails.Al Glidewell has scanned the photos of my college project with the VW van and we're going to see if we can get them posted here.The work was done 1979/1980 for a senior project at Texas Tech.A 1970 VW Transporter was modified with 0.32-inch thick aluminum full bellypan,cardboard and duct tape rear wheel skirts,and aluminum-over-wood skeleton 18-inch boat tail extension with increasing curvature up to an exit angle of 20-degrees,as measured from the vehicles longitudinal centerline.---------------- The "kit" provided an 26.8% mpg improvement in mpg.Cd was estimated at 0.35-o.32,from an original Cd0.455.Mpg was as high as 35.5 mpg at a steady 55-mph.






Attached Thumbnails
Click image for larger version

Name:	Untitled-4.jpg
Views:	1528
Size:	104.7 KB
ID:	3664  Click image for larger version

Name:	Untitled-3.jpg
Views:	1511
Size:	66.7 KB
ID:	3665  Click image for larger version

Name:	Untitled-2.jpg
Views:	10652
Size:	105.3 KB
ID:	3666  
  Reply With Quote
The Following 2 Users Say Thank You to aerohead For This Useful Post:
BamZipPow (01-12-2013), HHOTDI (01-12-2013)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 06-06-2009, 05:29 PM   #2 (permalink)
Master EcoModder
 
Join Date: Jan 2009
Location: Maui, Hawaii
Posts: 813
Thanks: 5
Thanked 32 Times in 25 Posts
Wow, that's a huge improvement. I wonder how much of the improvement is from the boattail, and how much from the belly pan
  Reply With Quote
Old 06-06-2009, 06:05 PM   #3 (permalink)
EcoModding Apprentice
 
Join Date: Feb 2009
Location: Bedfordshire, UK
Posts: 162
Thanks: 2
Thanked 2 Times in 2 Posts
I'm betting the belly pans didn't help much. - those vw campers had an almost smooth underbelly anyways, same as the beetles.

Would lowering it have helped at all?
  Reply With Quote
Old 06-06-2009, 07:39 PM   #4 (permalink)
Master EcoModder
 
bondo's Avatar
 
Join Date: Jan 2008
Location: Arkansas
Posts: 275
Thanks: 89
Thanked 226 Times in 85 Posts
That is over a 25% reduction in Cd! That is substantial. I thought I was doing good with a 10% reduction in Cd with the aerocap for pickups!

No wonder you know a little about aerodynamics, you have been doing neat stuff for 30 years now!

Thanks for sharing with us,

Bondo
  Reply With Quote
Old 06-06-2009, 08:54 PM   #5 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 19,375

Blackfly - '98 Geo Metro
Team Metro
90 day: 65.31 mpg (US)

ForkenSwift - '92 Geo Metro EV
Last 3: 95.68 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 38.25 mpg (US)
Thanks: 2,005
Thanked 4,723 Times in 2,364 Posts
Did you make any changes to permit engine cooling? Didn't the original design use the low pressure at the back to draw air through the engine compartment, exiting through vents on the back of the van?

Thanks for posting this, Phil.
__________________
Latest mods test: 15 mods = 15% MPG improvement: A-B test, 2007 Honda Civic 1.8L, 5-speed
Ecodriving test:
Manual vs. automatic transmission MPG showdown: Nissan Micra 1.6L



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
Old 06-06-2009, 11:50 PM   #6 (permalink)
(:
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 11,862

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

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

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

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

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,338
Thanked 2,826 Times in 1,804 Posts
VWs exhaust the cooling air underneath
  Reply With Quote
Old 06-07-2009, 02:21 AM   #7 (permalink)
is not covered in bees.
 
Istas's Avatar
 
Join Date: May 2009
Location: Seeley Lake, Montana, USA
Posts: 202

Honda - '05 Honda Accord EX
90 day: 32.86 mpg (US)
Thanks: 51
Thanked 42 Times in 21 Posts
Send a message via AIM to Istas
That really is an amazingly effective improvement. Thanks for sharing it with us!
  Reply With Quote
Old 06-07-2009, 10:05 AM   #8 (permalink)
Basjoos Wannabe
 
ShadeTreeMech's Avatar
 
Join Date: Apr 2009
Location: Arkansas
Posts: 870

The Van - '97 Mercury Villager gs
90 day: 19.8 mpg (US)

Lyle the Kindly Viking - '99 Volvo V70
90 day: 25.82 mpg (US)
Thanks: 174
Thanked 49 Times in 32 Posts
I suspect some of the increase in efficiency was helped by it having a really bad .455 cd. When you start bad, any improvement is substantial. I suspect if I were to do the same with my van, which already has a cd of .35, I would be lucky to net the same percentage decrease, which would be a .26

The work is indeed nice and clean, though. Reminds me of an Airstream travel trailer. Looks like the rear tailgate was completely inaccessible; wouldn't that be a problem for a VW camper come tune up time?
__________________
RIP Maxima 1997-2012


Quote:
Originally Posted by jamesqf View Post
I think you missed the point I was trying to make, which is that it's not rational to do either speed or fuel economy mods for economic reasons. You do it as a form of recreation, for the fun and for the challenge.
  Reply With Quote
Old 06-08-2009, 02:56 PM   #9 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 8,277
Thanks: 10,029
Thanked 4,316 Times in 2,389 Posts
how much

Quote:
Originally Posted by winkosmosis View Post
Wow, that's a huge improvement. I wonder how much of the improvement is from the boattail, and how much from the belly pan
Sorry,I didn't expect to be back at the computer 'til next weekend and I don't have my materials with me.When the testing was done,everything was done as a "kit"and I had to rely on published relationships to help sort it out.The reason for the boattail,was that from the published literature it promised significant improvements.----------- I'll bring my papers next time and post what I deduced.
  Reply With Quote
Old 06-08-2009, 03:07 PM   #10 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 8,277
Thanks: 10,029
Thanked 4,316 Times in 2,389 Posts
belly

Quote:
Originally Posted by vinny1989 View Post
I'm betting the belly pans didn't help much. - those vw campers had an almost smooth underbelly anyways, same as the beetles.

Would lowering it have helped at all?
My van was just the standard transporter and lacked all the Westfalia equipment,which I mimicked.The original underside was a deep,ladder-type frame with deep recesses.According to R.G.S.White's Method of Estimating Drag Coefficients,it had one of the worst undersides in the industry.After studying Aerodynamics of Road Vehicles by Skybor and Rylski,I was convinced that my VW was a premium candidate for the bellypan.--------- Lowering would have certainly helped,although would effect utility for the places I'm likely to go( I still have the van).Lowering any vehicle effectively increases its fineness ratio,reduces frontal area a smidge due to cloaking of the tires,and also lowers C.G.,all good things.

  Reply With Quote
The Following User Says Thank You to aerohead For This Useful Post:
HHOTDI (09-10-2013)
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Breakfast with Phil Knox bondo Aerodynamics 42 08-14-2010 05:49 PM
1976 vw van (seattle area) greggholmes For Sale 0 06-02-2009 12:15 AM



Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com