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


Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 06-06-2011, 04:54 AM   #1 (permalink)
aero guerrilla
 
Piwoslaw's Avatar
 
Join Date: Oct 2008
Location: Warsaw, Poland
Posts: 3,541

Svietlana II - '13 Peugeot 308SW e-HDI 6sp
90 day: 58.1 mpg (US)
Thanks: 1,056
Thanked 625 Times in 393 Posts
Trends in bus aerodynamics

In recent years I've noticed how the shape of long distance busses has evolved. First, the side mirrors, which are no longer fixed to the front corner where they kill airflow down the whole side:
but now hang down farther away, looking like bug antennae:

Next, the rounded front:
and roof extension:
as shown on a Volvo (Elite?).

Finally, (partial) rear wheel skirts, as shown on a Neoplan Starliner:
and on a Man:


The skirts may be more to control spray than for aero reasons, like the front skirts on city busses.

Unfortunately, busses have been getting taller (=more frontal area) to provide more luggage space. A partial alternative would be a piggyback luggage holder, only shaped like a Kammback
Or an aerotrailer.

Attached Thumbnails
Click image for larger version

Name:	Neoplan_Starliner_N516_SHD,_Riviera_-_rear.jpg
Views:	888
Size:	97.1 KB
ID:	8640   Click image for larger version

Name:	manskirt1.jpg
Views:	893
Size:	93.3 KB
ID:	8641   Click image for larger version

Name:	manskirt2.jpg
Views:	861
Size:	88.7 KB
ID:	8642  
__________________
e·co·mod·ding: the art of turning vehicles into what they should be

What matters is where you're going, not how fast.

"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell

Piwoslaw's Peugeot 307sw modding thread

  Reply With Quote
The Following 3 Users Say Thank You to Piwoslaw For This Useful Post:
aerohead (06-07-2011), Cd (06-06-2011), NeilBlanchard (06-07-2011)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 06-06-2011, 12:30 PM   #2 (permalink)
EcoModding Dilatant
 
Join Date: Jul 2008
Location: NC
Posts: 262

Volvo - '00 Volvo V70 XC AWD SE
90 day: 27.7 mpg (US)
Thanks: 4
Thanked 26 Times in 16 Posts
The hanging mirrors are mainly for safety. People standing on curbs kept getting smacked with the low mirrors.

And by the way, busses = kisses. Buses = more than one bus.
  Reply With Quote
Old 06-06-2011, 03:06 PM   #3 (permalink)
EcoModding Lurker
 
Join Date: Nov 2009
Location: Capetown, South Africa
Posts: 9
Thanks: 8
Thanked 1 Time in 1 Post
Some buses from the 50's and early 60's were well rounded on the front corners. Unfortunately, most were rounded at the rear as well, not taking advantage of the Kamm effect.

Like the Setra S6, S10, some old Neoplans and others.

The GM PD 4104 is rounded as well, and the body/chassis is from aluminum, for lighter overall weight. They are a popular choice for conversion to a motorhome. The later PD 4106, also aluminum, may be a good choice as well. Think those old rounded-rear buses can benefit from a boat-tail conversion...

That "square-look" fashioned buses from the late seventies and 80's was probably a step backwards aerodynamically wise, at the time.
  Reply With Quote
Old 06-06-2011, 03:15 PM   #4 (permalink)
aero guerrilla
 
Piwoslaw's Avatar
 
Join Date: Oct 2008
Location: Warsaw, Poland
Posts: 3,541

Svietlana II - '13 Peugeot 308SW e-HDI 6sp
90 day: 58.1 mpg (US)
Thanks: 1,056
Thanked 625 Times in 393 Posts
Quote:
Originally Posted by instarx View Post
And by the way, busses = kisses. Buses = more than one bus.
I wrote busses instead of buses because:
  1. Both plural forms are correct. 'Buses' is more popular, especially in the US, but since most of the examples in my post are from Europe I used the older, less American form.
  2. Today, June 6th, is Kissing Day here (one of three), as the media have been repeating over and over again. Hence, the 'buss'
  3. The word 'buses' could be read, according to English rules, to rhyme with 'fuses', but not 'fusses'. On the other hand, the pronounciation of 'busses' is more or less unequivocal (if the pronounciation of anything in English can be unequivocal).
__________________
e·co·mod·ding: the art of turning vehicles into what they should be

What matters is where you're going, not how fast.

"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell

Piwoslaw's Peugeot 307sw modding thread

  Reply With Quote
The Following User Says Thank You to Piwoslaw For This Useful Post:
oldtamiyaphile (03-22-2016)
Old 06-06-2011, 04:28 PM   #5 (permalink)
EcoModding Apprentice
 
Join Date: Apr 2011
Location: Houston
Posts: 228
Thanks: 0
Thanked 23 Times in 17 Posts
Quote:
Originally Posted by instarx View Post
The hanging mirrors are mainly for safety. People standing on curbs kept getting smacked with the low mirrors.

And by the way, busses = kisses. Buses = more than one bus.
I'm guessing that it REALLY bothers you that your title up under your name is spelled Dilatant?
  Reply With Quote
Old 06-06-2011, 04:31 PM   #6 (permalink)
EcoModding Apprentice
 
Join Date: Apr 2011
Location: Houston
Posts: 228
Thanks: 0
Thanked 23 Times in 17 Posts
I'm debating a roof extension like the Volvo's on my CR-V. The sides have a nice crisp break, but the top is curved. Worth the effort? Anyone?
  Reply With Quote
Old 06-06-2011, 05:10 PM   #7 (permalink)
EcoModding Dilatant
 
Join Date: Jul 2008
Location: NC
Posts: 262

Volvo - '00 Volvo V70 XC AWD SE
90 day: 27.7 mpg (US)
Thanks: 4
Thanked 26 Times in 16 Posts
Quote:
Originally Posted by Bill in Houston View Post
I'm guessing that it REALLY bothers you that your title up under your name is spelled Dilatant?
Never noticed it. But I'm guessing you'll have to talk to the person who created the ecomoddder titles to get it corrected.

And piwoslaw you are right - busses can mean more than one bus. I stand corrected. Interesting about it being kissing day, though. Should I plan my next trip to Europe for June 6?
  Reply With Quote
Old 06-06-2011, 07:58 PM   #8 (permalink)
Master EcoModder
 
Join Date: Jan 2009
Location: Maui, Hawaii
Posts: 813
Thanks: 5
Thanked 33 Times in 26 Posts
WTF is a dilatant?


Edit: Oh, it's a non newtonian fluid http://en.wikipedia.org/wiki/Dilatant

I've been wondering for a long time what the word for fluids like that is. Silly putty would be an example.
  Reply With Quote
Old 06-06-2011, 10:48 PM   #9 (permalink)
EcoModding Apprentice
 
Join Date: Apr 2011
Location: Houston
Posts: 228
Thanks: 0
Thanked 23 Times in 17 Posts
dilettante, i think, is what they were shooting for.
  Reply With Quote
The Following User Says Thank You to Bill in Houston For This Useful Post:
instarx (06-07-2011)
Old 06-07-2011, 09:53 AM   #10 (permalink)
Recreation Engineer
 
KamperBob's Avatar
 
Join Date: Dec 2009
Location: Somewhere USA
Posts: 520

Black Stallion - '02 Toyota Tundra 4WD xCab

Half Pint - '06 Yamaha XT225
Thanks: 308
Thanked 136 Times in 101 Posts
Quote:
Originally Posted by Dawie View Post
Some buses from the 50's and early 60's were well rounded on the front corners. Unfortunately, most were rounded at the rear as well, not taking advantage of the Kamm effect.
In Hucho 4th Ed 1998 page 204 is figure 4.101 showing the corner radius effect work of D.M. Waters 1969. The same figure in German appears in Peschke & Mankau 1982 which is available as a Google Book.



Waters' work was based on a (camper) trailer (my area of interest) towed behind a car so the flow field conditions are not quite the same as a bus but I see a feature worth noting. The solid curve shows marginal diminishing return from nose rounding. The dashed curve shows much more dramatic improvement for a rectangular block with all corners radiused not just the front. I'd love to sink my teeth into Water's original paper.

Meanwhile, the rounded rump of a vintage bus seems pretty beneficial. A lot of Airstream trailers and other brands benefit from a similar shape by all accounts I have found (mostly owner reports comparing rounded to boxy units).

Attached Thumbnails
Click image for larger version

Name:	Bild 4.128.png
Views:	933
Size:	23.9 KB
ID:	8647  
__________________
Recreation Engineer
  Reply With Quote
The Following User Says Thank You to KamperBob For This Useful Post:
slowmover (06-11-2011)
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com