MPG VS. SPEED
#21
Originally Posted by Longsnowsm
Freightliner is talking about the Cascadia as being the slickest truck out there, but to look at it and thinking about how air moves and works I am not buying it.
I would love to see some heads up aero comparisons with the latest aero trucks to really see what we are talking about as far as aero advantages.
#23
Senior Board Member
Join Date: Dec 2005
Posts: 576
I agree that the amount of frontal area is key to CD numbers, but it also depends on shapes and how the air is managed/moved out of the way. The cabovers have the aero profile of a barn door so I have my doubts about the CD numbers a cabover would generate compared to the more aero trucks. If anything I would think the weight advantages of the cabover would have a bigger impact than the aero. Again it sure would be nice to see some of this data.
That is precisely why I am doubting the Cascadia claims to the aero king. The size if the radiator area is huge(both tall and wide). The surface area is just too large, too flat, and the grill openings just too big to believe that there is an aero advantage here. Also I pay paticular attention to the rake and angle of the windshield and compare that to the one truck we know for certain was designed with aero in mind from day one the T2000. That rake of of the windshield and up over the cab is critical as is the movement along the sides of the truck. How that air moved and redirected is key. The Cascadia still appears to have much of the same profile of the Columbia in this regard. The Columbia actually looks more aero in the grill radiator area, but less along the fenders back side. The only thing that appears interesting with the Cascadia is the way that the front fenders blend and fade into the body of the truck to smooth that air that would otherwise be turbulent over those fenders and along the doors. The typical shape would cause the air to be turubulent and roll and create turbulence, drag, and noise. The other thing I don't understand is why the major carriers don't spec out the trucks with the side skirts to manage the air along side of the truck. Seems like a lot of the big carriers don't buy trucks with the side skirts. The numbers from KW seem to indicate those skirts do more than dress up the truck and should net a savings in fuel costs. While I love the look of a long nose KW/PB, I am practical and as far as a truck is concerned it is all about the business and the money the truck earns/and I keep. So in my mind make a truck that looks like a bullet and as slick/efficient as possible. The one thing I did find interesting on the Cascadia was the battery pack unit instead of an APU. That is an interesting thought, but the batterys will be heavier than a ICE that uses desiel. However with the no idling rules being extended to even APU's the battery idea may be the only real choice. Thoughts? Longsnowsm
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#24
Senior Board Member
Join Date: Jan 2005
Location: over here
Posts: 1,011
where`d you hear about the anti idling laws including apu`s?
the best way I can explain the whole aero thing is picture a columbia, the grille area is relatively small and gets wider as ya get to the back of the hood, the nose doesnt break the surface much and all that air ends up riding the sides of the hood all the way up to the cab, now on my 900 the grilles so damn big i`m punching a huge hole through the air and its not touching my hood but i`ve got so much other crap sticking out in the wind thats grabbing it, although in some cases the fuel mileage lost is neglible, i`m averaging 6.3mpg pulling a skateboard mostly in wyoming with 75mph speed limits, part of the reason for imo exceptional fuel mileage with a hood is tall rubber, real low (numerically) gears in the axles and alot more torque then the c15 came with, with alot more torque down low i`ll short shift up to 18th never going over 1450 rpm`s and cruise about 400 rpm lower then most other trucks.
#25
Senior Board Member
Join Date: Dec 2005
Posts: 576
Here is the rule that goes into affect in CA(2008) that effectively will ban the use of APU's unless they have emissions gear that is cleaner than anything currently out there:
http://www.ttnews.com/articles/baset...?storyid=17425 So I imagine this is why we are seeing the battery powered units showing up. I have also read several articles and posts about people with APU's in anti-idling states getting finded for running the APU. I question how legal these tickets were and it sounds to me like ill informed law enforcement on the loose. The laws in CA will filter across the rest of the country. It is only a matter of time. They don't care if your freezing to death or roasting in that truck. I think if they are going to go that far they should make it mandatory that all truck stops have shore power and at a big discount. I am surprised that this state doesn't get boycotted. Longsnowsm
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Politicians are a lot like diapers, They should be changed frequently, And for the same reasons.
#27
Member
Join Date: Apr 2007
Posts: 77
Very interesting:
First of all a) i don't see how a company driver will benefit from going slower in the long run unless you're getting a fuel bonus or something. This is asuming you're not sacrificing safety by going faster. Which IS possible. b)I've done a lot of number crunching and It ALWAYS benefits an O/O to go faster is it maximizes profit per week. Remember profit = revenue-expenses. Yes, MPG will go down. But unless you're an idiot the load always pays more than what fuel and any other expenses costs. So the more loads you pull the more money you end up with. Yes, maintenance costs go up (a little). Again read above. Again, this is assuming you are not affecting safety by going faster. And there are ways to stay safe while driving 65-70 or more.
#28
Originally Posted by brian griffin
b)I've done a lot of number crunching and It ALWAYS benefits an O/O to go faster is it maximizes profit per week. Remember profit = revenue-expenses.
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#29
Originally Posted by brian griffin
b)I've done a lot of number crunching and It ALWAYS benefits an O/O to go faster is it maximizes profit per week. Remember profit = revenue-expenses.
Originally Posted by solo379
I'd love to see those numbers! :P
#30
Senior Board Member
Join Date: Mar 2006
Location: Las Cruces, NM
Posts: 1,004
Originally Posted by Longsnowsm
Here is the rule that goes into affect in CA(2008) that effectively will ban the use of APU's unless they have emissions gear that is cleaner than anything currently out there:
http://www.ttnews.com/articles/baset...?storyid=17425 So I imagine this is why we are seeing the battery powered units showing up. I have also read several articles and posts about people with APU's in anti-idling states getting finded for running the APU. I question how legal these tickets were and it sounds to me like ill informed law enforcement on the loose. The laws in CA will filter across the rest of the country. It is only a matter of time. They don't care if your freezing to death or roasting in that truck. I think if they are going to go that far they should make it mandatory that all truck stops have shore power and at a big discount. I am surprised that this state doesn't get boycotted. Longsnowsm
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