Reply
 
Thread Tools Display Modes
 
Old 03-27-2019, 01:47 AM   #1
Bus Crazy
 
Sleddgracer's Avatar
 
Join Date: Nov 2018
Location: south east BC, close to the Canadian/US border
Posts: 2,265
Year: 1975
Coachwork: Chevy
Chassis: 8 window
Engine: 454 LS7
Rated Cap: 24,500
bus aerodynamics

https://www.tc.gc.ca/en/programs-pol...cks-buses.html
Sleddgracer is offline   Reply With Quote
Old 03-27-2019, 02:17 AM   #2
Bus Crazy
 
turf's Avatar
 
Join Date: Apr 2013
Location: Colorado
Posts: 1,600
Year: 1993
Coachwork: bluebird
Engine: 5.9 Cummins, Allison AT1545
Rated Cap: 2
if money were no object, i've been dreaming up a boattail i want to try to lessen the drag
__________________
.
Turfmobile Build Thread
turf is offline   Reply With Quote
Old 03-27-2019, 03:11 AM   #3
Bus Crazy
 
Join Date: Sep 2015
Posts: 1,238
Year: 2002
Coachwork: Thomas Built Bus
Chassis: Freightliner FS65
Engine: Caterpillar 3126E Diesel
Rated Cap: 71 Passenger- 30,000 lbs.
That was an interesting read, thank you!
Native is offline   Reply With Quote
Old 03-27-2019, 03:14 AM   #4
Bus Crazy
 
Join Date: Sep 2015
Posts: 1,238
Year: 2002
Coachwork: Thomas Built Bus
Chassis: Freightliner FS65
Engine: Caterpillar 3126E Diesel
Rated Cap: 71 Passenger- 30,000 lbs.
Quote:
Originally Posted by turf View Post
if money were no object, i've been dreaming up a boattail i want to try to lessen the drag

According to that article, you do not need a full boat tail, just 24-32 inches. Heck, you have probably seen tractor-trailers with those "box-kite"-like farings on the back end. That is what they are for ... to reduce the drag on the end.
Native is offline   Reply With Quote
Old 03-27-2019, 07:11 AM   #5
Bus Crazy
 
Ronnie's Avatar
 
Join Date: Oct 2017
Location: Virginia
Posts: 1,160
Year: 1971
Coachwork: Wayne
Chassis: International Loadstar 1700
Engine: 345 international V-8
I wonder how much difference the tails on trucks actually do? a few percent, 10%, 20%?
Ronnie is offline   Reply With Quote
Old 03-27-2019, 07:27 AM   #6
Bus Crazy
 
Ronnie's Avatar
 
Join Date: Oct 2017
Location: Virginia
Posts: 1,160
Year: 1971
Coachwork: Wayne
Chassis: International Loadstar 1700
Engine: 345 international V-8
It will take a while to fully read this article, but seems worth it, thanks for posting.
Ronnie is offline   Reply With Quote
Old 03-27-2019, 08:40 AM   #7
Bus Crazy
 
turf's Avatar
 
Join Date: Apr 2013
Location: Colorado
Posts: 1,600
Year: 1993
Coachwork: bluebird
Engine: 5.9 Cummins, Allison AT1545
Rated Cap: 2
this isnt a new article.

i believe it states that about half of the drag comes from the front, and half comes from the back. a tail only should be 5% fuel savings. wheel covers will get you another 2-3%
__________________
.
Turfmobile Build Thread
turf is offline   Reply With Quote
Old 03-27-2019, 12:13 PM   #8
Bus Crazy
 
Sleddgracer's Avatar
 
Join Date: Nov 2018
Location: south east BC, close to the Canadian/US border
Posts: 2,265
Year: 1975
Coachwork: Chevy
Chassis: 8 window
Engine: 454 LS7
Rated Cap: 24,500
I've been thinking that a 10% fuel saving would amount to a lot of money in the end - I doubled my mileage from 3 1/2 mpg to 7 mpg by adding a concave scoop to the front of an awkward load on one truck I had, so I know from experience how much an afternoon's work can save in fuel - I'm likely going to be doing a roof raise when I get my bus and I'll seriously consider getting rid of the typical flat forehead of a school bus and do a nice swooping roof line up to the transition, perhaps over an area 10' long - an air dam under the bumper , plus some hub caps ( who doesn't like a shiny set of hub caps on an old vehicle? ) - I haven't looked in to a fairing at the back yet, but if it can save even 1 or 2%, long term, would be worth a bit of fabrication - I don't know if a 'bug shield' on the hood would help or not, but it might help direct the airflow past that flat sail of the windshield - apparently mirrors can add significant drag, so perhaps a bit less ambitious set of mirrors would help along with one or two back up cameras - I recently put a new set of trailer towing mirrors on my pickup - they extend outwards when you need them and give a nice area of view - not as good as a set of West Coast mirrors maybe, but pretty good and certainly less drag than the West Coast mirrors - so if all that gets me a 10% saving, I'll save a couple hundred dollars each time I travel north in the winter
Sleddgracer is offline   Reply With Quote
Old 03-27-2019, 01:34 PM   #9
Bus Geek
 
Join Date: May 2016
Location: Eastern WA
Posts: 5,767
Year: 2002
Coachwork: Bluebird
Chassis: All American RE (A3RE)
Engine: Cummins ISC (8.3)
Rated Cap: 72
Neat site discussing economy minded mods: https://ecomodder.com/forum/showthre...ero-34627.html
PNW_Steve is online now   Reply With Quote
Old 03-27-2019, 05:35 PM   #10
Bus Crazy
 
Sleddgracer's Avatar
 
Join Date: Nov 2018
Location: south east BC, close to the Canadian/US border
Posts: 2,265
Year: 1975
Coachwork: Chevy
Chassis: 8 window
Engine: 454 LS7
Rated Cap: 24,500
Quote:
Originally Posted by PNW_Steve View Post
Neat site discussing economy minded mods: https://ecomodder.com/forum/showthre...ero-34627.html
I enjoyed that site and learned a bit at the same time
Sleddgracer is offline   Reply With Quote
Old 03-27-2019, 06:20 PM   #11
Bus Geek
 
o1marc's Avatar
 
Join Date: Dec 2017
Location: Dawsonville, Ga.
Posts: 8,553
Year: 1999
Coachwork: Genesis
Chassis: International
Engine: DT466/3060
Rated Cap: 77
Quote:
Originally Posted by Sleddgracer View Post
I've been thinking that a 10% fuel saving would amount to a lot of money in the end - I doubled my mileage from 3 1/2 mpg to 7 mpg by adding a concave scoop to the front of an awkward load on one truck I had, so I know from experience how much an afternoon's work can save in fuel - I'm likely going to be doing a roof raise when I get my bus and I'll seriously consider getting rid of the typical flat forehead of a school bus and do a nice swooping roof line up to the transition, perhaps over an area 10' long - an air dam under the bumper , plus some hub caps ( who doesn't like a shiny set of hub caps on an old vehicle? ) - I haven't looked in to a fairing at the back yet, but if it can save even 1 or 2%, long term, would be worth a bit of fabrication - I don't know if a 'bug shield' on the hood would help or not, but it might help direct the airflow past that flat sail of the windshield - apparently mirrors can add significant drag, so perhaps a bit less ambitious set of mirrors would help along with one or two back up cameras - I recently put a new set of trailer towing mirrors on my pickup - they extend outwards when you need them and give a nice area of view - not as good as a set of West Coast mirrors maybe, but pretty good and certainly less drag than the West Coast mirrors - so if all that gets me a 10% saving, I'll save a couple hundred dollars each time I travel north in the winter
I doubt there is a 10% difference, but a 4% difference over 1,000,000 miles would be substantial. Probably negligible results for the mileage we see. At $3/g you would spend $300000 in fuel at 10mpg. 4% over a million saves you $12k, 10% saves you $30k
o1marc is online now   Reply With Quote
Old 03-27-2019, 08:18 PM   #12
Bus Crazy
 
Sleddgracer's Avatar
 
Join Date: Nov 2018
Location: south east BC, close to the Canadian/US border
Posts: 2,265
Year: 1975
Coachwork: Chevy
Chassis: 8 window
Engine: 454 LS7
Rated Cap: 24,500
Quote:
Originally Posted by o1marc View Post
I doubt there is a 10% difference, but a 4% difference over 1,000,000 miles would be substantial. Probably negligible results for the mileage we see. At $3/g you would spend $300000 in fuel at 10mpg. 4% over a million saves you $12k, 10% saves you $30k
I just spent too much of my day reading about improving aerodynamics ( thankfully it's been a slow day here at the kennels ) - sites about improving a semi's mileage, a couple of old skoolie threads about the subject of improving air resistance on buses - I'm planning on a roof raise and that will give me the opportunity to alter the profile of the roof line, rounding off both front and back, at no or little extra cost ( labour not taken into account ) -using conveyor belting to make a front air dam, side skirts, and an abbreviated tail to reduce wind turbulence at the back, will make quite a difference - belting can be low to the ground for maximum effect and is flexible if more ground clearance is needed - I'm pretty sure I can get all the belting I need for a case of beer - so the cost of going for some aerodynamic improvements will be small and going by the improvements in mileage I achieved with a simple scoop on the awkward load I mentioned before, I think a 10% improvement is reachable - with the $6.40 we are paying here for an Imperial gal of cheap gas, that 10%, or even less of an improvement, will make quite a difference on a 2000 or 3000 mile trip - if it's only 10%, I'll could save $240 on one 3000 mile trip
Sleddgracer is offline   Reply With Quote
Old 03-28-2019, 01:39 AM   #13
Bus Crazy
 
Join Date: Sep 2015
Posts: 1,238
Year: 2002
Coachwork: Thomas Built Bus
Chassis: Freightliner FS65
Engine: Caterpillar 3126E Diesel
Rated Cap: 71 Passenger- 30,000 lbs.
Quote:
Originally Posted by Ronnie View Post
I wonder how much difference the tails on trucks actually do? a few percent, 10%, 20%?

The study did not break down the effectiveness of the boat tails alone but in conjunction with gap closure devices (busses have no gap) and skirts (some have low skirts). The total the study quotes is up to 14% fuel savings.
Native is offline   Reply With Quote
Old 03-28-2019, 05:15 AM   #14
Bus Nut
 
Join Date: Jan 2016
Posts: 252
Thanks for the discussion. Google did not show me what a "boat tail" is. Can someone post a pic? I want a RE type D because it provides the greatest amount of underfloor storage, but gives the aerodynamics of driving a brick. Is handling also a byproduct of aerodynamics? i.e. will a vehicle with better aerodynamics have better handling characteristics? Hub caps sound like an easy to do thing. I remember during the "oil crisis" in the 70's there were car designs that covered up the top half of the rear wheels in an attempt to get better mpg. Has anyone considered enclosing the bottom of the bus completely (maybe its called a belly pan)? While reading about vans I heard that this gives 5-7% better mpg. If you compare the Greyhound buses with our skoolies, you will find that the windows don't open on the GH busses and provide a really smooth, slick surface down the side. It is not something that most people would address if you have finished a conversion, but if you are going to be putting significant miles on the bus and are at the beginning of your conversion, it might be something to consider. A lot trucks and cars come with wheel wells lined with hard plastic...is this helpful?


Maybe people raising the tops should think about this:



I know it is not reasonable to compare Greyhound with our skoolies. GH buses use something like unibody construction, which makes it lighter, uses aluminum in a lot of places, so also is lighter, etc. I sometimes "go greyhound" and the service people tell me that their buses get 10-11 mph at highway speeds, usually 65mph or more. Still maybe there is something to learn from them.


I am not an autocad person, but a long-time-ago friend of mine could speak "Autocad" better than he could speak English. He had some kind of add-in to AC that measured drag of an object....is anyone familiar with this?
pengyou is offline   Reply With Quote
Old 03-28-2019, 07:25 AM   #15
Bus Crazy
 
Ronnie's Avatar
 
Join Date: Oct 2017
Location: Virginia
Posts: 1,160
Year: 1971
Coachwork: Wayne
Chassis: International Loadstar 1700
Engine: 345 international V-8
Did you notice it said flat front was better then dog nose? I saw that and been thinking about it since. I really do not like the look of flat front. A Crown bus yes or an old GM.

I have an old "Silver Streak" camping trailer and it is build with a full belly pan. From a maintenance standpoint seems like a lot of trouble for a bus. An airdam might be better, and bring the side skirts lower?

Must say looking at my skoolie it is not clean, ie two rooftop a/c, two roof vents, solar panels, low railing around a deck area, and plumbing vent pipe.
Ronnie is offline   Reply With Quote
Old 03-28-2019, 07:29 AM   #16
Bus Geek
 
EastCoastCB's Avatar
 
Join Date: Sep 2014
Location: Eustis FLORIDA
Posts: 19,385
Year: 1999
Coachwork: Thomas
Chassis: Freighliner FS65
Engine: Cat 3126
Rated Cap: 15
These get 18-20 mpg.
__________________
.
Roll Your Own Build Thread
EastCoastCB is offline   Reply With Quote
Old 03-28-2019, 08:49 AM   #17
Bus Crazy
 
Sleddgracer's Avatar
 
Join Date: Nov 2018
Location: south east BC, close to the Canadian/US border
Posts: 2,265
Year: 1975
Coachwork: Chevy
Chassis: 8 window
Engine: 454 LS7
Rated Cap: 24,500
'was doing some more searching last night and came across some new technology being used on heavy trucks - one is a guide installed under the truck that steers the air past the outside of the rear wheels - it starts narrow and gradually widens giving sort of a funnel effect it looks like - truckers claim it adds stability in cross winds and better handling on the road - another idea was an air dam installed in front of the rear axle that forces the air to the outside of the dual wheels
Sleddgracer is offline   Reply With Quote
Old 03-28-2019, 09:35 AM   #18
Bus Crazy
 
Sleddgracer's Avatar
 
Join Date: Nov 2018
Location: south east BC, close to the Canadian/US border
Posts: 2,265
Year: 1975
Coachwork: Chevy
Chassis: 8 window
Engine: 454 LS7
Rated Cap: 24,500
aerodynamics has been a concern for a while
Attached Images
File Type: jpg Labatt-Streamliner-808x455.jpg (42.1 KB, 18 views)
Sleddgracer is offline   Reply With Quote
Old 03-28-2019, 04:11 PM   #19
Bus Crazy
 
Sleddgracer's Avatar
 
Join Date: Nov 2018
Location: south east BC, close to the Canadian/US border
Posts: 2,265
Year: 1975
Coachwork: Chevy
Chassis: 8 window
Engine: 454 LS7
Rated Cap: 24,500
boat tail demonstration
Sleddgracer is offline   Reply With Quote
Old 03-28-2019, 04:18 PM   #20
Bus Crazy
 
Join Date: Sep 2015
Posts: 1,238
Year: 2002
Coachwork: Thomas Built Bus
Chassis: Freightliner FS65
Engine: Caterpillar 3126E Diesel
Rated Cap: 71 Passenger- 30,000 lbs.
Cool demo, thank you!
Native is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 10:31 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
×