Author Topic: Front spoiler/air dam for mileage  (Read 30110 times)

Offline Len Silva

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Re: Front spoiler/air dam for mileage
« Reply #45 on: August 15, 2007, 12:15:15 PM »
I worked with a guy who had been an engineer with Eagle back in their glory days.  He told me that they did wind tunnel tests and that the Eagle is actualy tapered about 2" along the sides starting about 10 feet from the rear.

Eagles have been known for superior economy compared to other similar sized busses so I guess it's true.  Anyone who's done serious reconstruction can probably verify that for me.

Len

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Songman

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Re: Front spoiler/air dam for mileage
« Reply #46 on: August 15, 2007, 12:33:27 PM »

Songman said he might be able to help with some photoshoping. I think it would look good, but photoshop will tell. I just need to get him some pix.
 
 (by the way, thanx Songman! I'll get some out to ya soon!)


No problem, glad to help.

Funny that Moon Eyes came up. The Photoshopped pictures I sent Chaz included the PS I did to see if I would like Moon Eyes on my wife's HHR. I didn't think I would like the look but Photoshop proved to me that I did so we ended up buying them. The other Photoshopped items are still in the works.


Offline JohnEd

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Re: Front spoiler/air dam for mileage
« Reply #47 on: August 15, 2007, 11:47:32 PM »
Weren't the older 7's and 8's easier to push down the road because their roof was curved at the sides?  Aren't square edges on the sides of a roof a serious aero drag?  I once ran into a trucker that was converting an old Sceinic Cruiser.  The bus had an 8v71...I guess.  It was a three speed stick and I marveled that it could do 60 and still get itself underway.  That trucker SEEMED an honest sort and he did have a really nice store bought oak bed set with the drawers underneath that he said his wife demanded.  He claimed that the bus gave him 10 MPG.  10MPG!  What do those old 4104's get with a stick?  I am guessing that the body shape has somthing to do with the outstanding mpg.

Comments?

thanks,

John
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Offline Jeremy

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Re: Front spoiler/air dam for mileage
« Reply #48 on: August 16, 2007, 03:32:01 AM »
Weren't the older 7's and 8's easier to push down the road because their roof was curved at the sides?  Aren't square edges on the sides of a roof a serious aero drag?  I once ran into a trucker that was converting an old Sceinic Cruiser.  The bus had an 8v71...I guess.  It was a three speed stick and I marveled that it could do 60 and still get itself underway.  That trucker SEEMED an honest sort and he did have a really nice store bought oak bed set with the drawers underneath that he said his wife demanded.  He claimed that the bus gave him 10 MPG.  10MPG!  What do those old 4104's get with a stick?  I am guessing that the body shape has somthing to do with the outstanding mpg.

Comments?

thanks,

John

I've often wondered whether modern square buses are aerodynamically much worse than the old-style curved coaches - especially those with the streamlined and tapered tails such as the Setra S6:



One thing that is often overlooked I think is the general 'smoothness' of the overall body - any projection or irregularity causes turbulence, and modern buses are generally very smooth indeed compared to the ones we drive. I read a statistic once about the total amount of petrol 'wasted' worldwide by the door mirrors on cars - I forget the number, but it was tens of millions of gallons a year.

As it happens I was parked next to the six-wheel versions of one of these yesterday - note the wheel covers:



Whilst looking for that photo I came across this one, which appears to have a number of interesting aerodynamic aids:



Here's an interesting comparison of the front of a Cityliner next to a more conventional bus:



Lastly, a concept drawing showing an idea for an aerodynamic rear (and enclosed rear wheels) on a modern bus. No attempt to smooth the airflow off the roof though:



Jeremy
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Offline Chaz

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Re: Front spoiler/air dam for mileage
« Reply #49 on: August 16, 2007, 06:13:11 AM »
Great stuff John and Jeremy!!!!!! Thanx!!

 By the way, those are some cool looking bus pictures Jeremy!! The blue Cityliner is WAAAAAAY cool. But then I like that Setra S6 too!

 So many bus's, so little time!
     Chaz

Hey SKIP!!!!!!!! Do ya know anywhere I could get some sort of technical data or at least "rule of thumb" for a visor? I'm really liking that idea. And before I go putting time into creating something, or asking Songman to give me a better idea of what it would look like, I'd like to know if there is any info out there.
   Thanx buddy!
Pix of my bus here: http://s58.photobucket.com/albums/g279/Skulptor/Motor%20Coach/
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maria-n-skip

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Re: Front spoiler/air dam for mileage
« Reply #50 on: August 16, 2007, 07:39:40 AM »
Chaz,

    Mostly the school of hard knocks! I put a Visor on my 48 Dodge pickup (389 3 dueces on a 68 Chevy pu frame) it came off an early 50's Chevy sedan. The visor is set up so the angle can be changed. Side supports and a center support. I'll take some pix so you can see. (probably have to do it later this evening)

  Lessons learned.

    Allow some space between the visor and the cab. (almost ripped off at 80mph) The force is quit substantual.
    The angle makes a diff on how much air it grabs.
    14 gauge (about what it is) is a little light and still flexes quit a bit.


    FWIW
  Skip

   

Offline tekebird

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Re: Front spoiler/air dam for mileage
« Reply #51 on: August 16, 2007, 11:15:24 AM »
I don't think a visor is going to gain you any perfomance. 

Offline Chaz

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Re: Front spoiler/air dam for mileage
« Reply #52 on: August 16, 2007, 03:58:02 PM »
You "don't think" or you "know"? >:(
Pix of my bus here: http://s58.photobucket.com/albums/g279/Skulptor/Motor%20Coach/
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Offline tekebird

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Re: Front spoiler/air dam for mileage
« Reply #53 on: August 16, 2007, 04:29:55 PM »
I admit I do not know........and there are newer trucks with OEM apendages that I am sure are designed with help of a windtunnel either to aid airflow or to Fix a design problem elswere.  I would not call any of these a Visor like we are talking about here ala 50's choped car style.

One would have to allow all air going under the visor the ability to escape without creating preasure under the visor.  Preasure under the visor will craet an eddy thus drag.

thats what the Spoiler on the rear of some high end motorhomes and the like are attempting to do...reduce the Eddy by creating an artificial streamline


maria-n-skip

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Re: Front spoiler/air dam for mileage
« Reply #54 on: August 16, 2007, 05:25:33 PM »

 please excuse daughter is tearing apart to rebuild  :)

   How about ala pre 50   8)

   The second pic show how the center adjust is set-up.
    To much pressure will rip the visor off!

Skip

Songman

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Re: Front spoiler/air dam for mileage
« Reply #55 on: August 16, 2007, 06:49:57 PM »
Nice old Dodge. I had a 46 International pickup street rod a few years ago.

maria-n-skip

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Re: Front spoiler/air dam for mileage
« Reply #56 on: August 16, 2007, 07:31:04 PM »

 Songman thanks.
   The daughter was wound up about the rust on the Aerodyne sleeper part.
   
   I told her she was just getting ready to own an Eagle.

   Boy you got to start these kids early. She is already looking on E-bay for a bus for her family.
   I must have done something right (oh lord what have I done)  ;D

  Later
 Skip

Offline Chaz

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Re: Front spoiler/air dam for mileage
« Reply #57 on: August 17, 2007, 09:06:54 AM »
Neat truck. (for a Mopar!  ;D lol    J/K after a certain age, they're ALL cool!) I have a '39 Chevy truck that I may have to sell to be able to afford my bus. Bummer!!! I'm not one who sells anything!!
  I also have a visor for the'51 Chevy Sedan I'm choppin. Probably can't use it after I get the lid lowered down to where I want it.
  I don't think I would use that particular style of visor. It's a little too round for the bus. But I think keeping it on the "rounded side" would be important for looks.  I would want to slant it down as much as feasible and possible to try to get the benefit - However small, tekebird.- that it could create.
  I have been watching semi's a bit more closely on how they have theirs and some of them on what looks like conventional Petes have almost a grader blade look to them. That's a little too much i think.
  When I get some drawings done, I'll put them out for critiques!  ;)  ;D
 
   Ol' skool bussin,
           Chaz
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Offline compedgemarine

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Re: Front spoiler/air dam for mileage
« Reply #58 on: August 17, 2007, 04:34:47 PM »
just a stupid thought but as we all know the worst part is the vacume created at the rear. most of the air entering the engine bay seems to be designed to flow out the bottom of the bay. I know my Eagle has very limited air flow through the rear door. could you not gain by letting the vacume at the rear pull the air out of the engine bay which by theory move more air through the bay reducing temps and reduce the vacume at the rear to help reduce drag?
Steve
1981 Eagle 10
also while a spoiler on the front to reduce under chassis air is great I dont know how long it would live as the overhang from the front tires makes drives and parking lots tough. I know mine has hit the ground a time or 50 in its transit days.

Offline tekebird

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Re: Front spoiler/air dam for mileage
« Reply #59 on: August 17, 2007, 05:13:21 PM »
I took a good look at a newer Freighliner today with an OEM Visor.

looks to me that most of it's work is done by directing the airflow that hits the windshield and goes up.....onto /parallel to the roof where it then hits the big aerodynamic cap which basically does the same thing for the trailer.

it's outlets were above cab roof level

 

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