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DMiller 
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Joined: 14 Sep 2009
Location: Hermann, Mo
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 Topic: Enganears falling back
Posted: 07 Feb 2023 at 7:21am |
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As to Aerodynamics on slow moving machines. Trains, Trucks, most autos never see speeds where aero features can come into play. Sad to watch old theories already ash canned coming back into view. HD Trucks show the most where few to any of them ever get past Turbulence air stream speeds, and yet they keep packing on sweeping shields and ground effects panels. Be better off without the excess weight.
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steve(ill)
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Joined: 11 Sep 2009
Location: illinois
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Posted: 07 Feb 2023 at 7:58am |
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hanging on EXTRA weight dont help.. Designing flowing curves instead of a flat wall in the INITIAL design is a better idea...... Stick your hand out the window going 60 MPH.. hold it horizontal like an airplane wing... then turn it 90 degrees like a FLAT WALL........ Too many big trucks have been the flat wall design in the past.
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Like them all, but love the "B"s.
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DMiller
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Location: Hermann, Mo
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Posted: 08 Feb 2023 at 4:20am |
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Largest area that has to be ‘in the wind’ is cooling system. Cannot streamline that away as then will not cool unless do as transit bus design and add HP stealing additional fans and resistance causing ducting into the mix.
HDTrucks got so bad with aero shields air conditioners and transmission coolers failed to function. Have to have some slipstream air across machinery or it cooks on its own. Most recent result is major improvement to brakes going Disc on tractor trailers is nearly no air flow to cool brakes off, rotor and pad failures increasing exponentially. The add of Wheel smoothing covers made this very angry. The added heat retention allows DEF/SCR DPF systems function better for awhile where random fires related to close proximity components has become Less random. Fix one concern theoretically and make three more problems.
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jaybmiller
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Joined: 12 Sep 2009
Location: Greensville,Ont
Points: 24657
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Posted: 08 Feb 2023 at 6:19am |
yup..
EVERY mod, upgrade, improvement works GREAT, in their computers.... .., and .... EVERY mod, upgrade, improvement works FAILS, in the REAL WORLD !!!!
Seen this happen too many times, in everything NOt just 'trucks'.
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3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)
Never burn your bridges, unless you can walk on water
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DMiller
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Posted: 08 Feb 2023 at 6:28am |
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Same here. Cat and other HE or HD Trucks using High Tech CANBUS systems failing now due to high vibration, severity of day to day climate changes on machines, even in our cars, debris and filth encroachment, Multiple Modules failing to play with joy stick controllers and mechanisms self destructing due to moisture or detritus involvement.
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jaybmiller
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Joined: 12 Sep 2009
Location: Greensville,Ont
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Posted: 08 Feb 2023 at 8:10am |
'high tech' CANbus... sigh, what a friggin JOKE
I KNOW NISSAN doesn't know how to implement it !!
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3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)
Never burn your bridges, unless you can walk on water
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Coke-in-MN
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Joined: 12 Sep 2009
Location: Afton MN
Points: 41979
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Posted: 09 Feb 2023 at 6:35pm |
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Life lesson: If you’re being chased by a lion, you’re on a horse, to the left of you is a giraffe and on the right is a unicorn, what do you do? You stop drinking and get off the carousel.
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AC7060IL
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Joined: 19 Aug 2012
Location: central IL
Points: 3530
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Posted: 09 Feb 2023 at 10:33pm |
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In the 1980s, if a semi averaged 5 mpg & drove 100,000 miles a year, it’s annual fuel budget was 20,000 gallons@ 80cents/gal~$16,000.
Today’s canbus semi might average 7-9mpg. Today’s $4.25/gallon fuel is 5 times more costly than the 1980s. So today’s 100,000 miles/year@7mpg~ $61,000 fuel budget! At 8mpg~$53,000 and at 9mpg~&47,000. So on those WINDY days, if the shields you’re relating about help yield another 1-2mpg then that’s easily worth $100-200/day fuel savings!!
Weight plays a direct factor, but WIND LOAD, can be significant. Diagonal headwinds are worse than direct headwinds cause diagonals not only buffet the trucks face, but EVERY side resistance along the entire rig. So a semi hauling any irregular shaped equipment/cargo is far worse than a more symmetrical straight panel trailer in a headwind diagonal. Don’t believe me? Just watch a semi’s EGTs per same weight/cargo per weather winds. Higher the EGTs, the higher the fuel consumption. If wind speeds & directions stay constant, the ONLY way to conserve fuel usage is by decreasing throttle which decreases wind speed....... Or maybe add a few wind jammer shields to the rig? Oh and that 1980s flat faced semi rig averaging 5mpg would need $85,000 annual fuel budget today.
Edited by AC7060IL - 09 Feb 2023 at 11:22pm
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DMiller
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Posted: 10 Feb 2023 at 5:52am |
 AC7060IL wrote:
In the 1980s, if a semi averaged 5 mpg & drove 100,000 miles a year, it’s annual fuel budget was 20,000 gallons@ 80cents/gal~$16,000.
Today’s canbus semi might average 7-9mpg. Today’s $4.25/gallon fuel is 5 times more costly than the 1980s. So today’s 100,000 miles/year@7mpg~ $61,000 fuel budget! At 8mpg~$53,000 and at 9mpg~&47,000. So on those WINDY days, if the shields you’re relating about help yield another 1-2mpg then that’s easily worth $100-200/day fuel savings!!
Weight plays a direct factor, but WIND LOAD, can be significant. Diagonal headwinds are worse than direct headwinds cause diagonals not only buffet the trucks face, but EVERY side resistance along the entire rig. So a semi hauling any irregular shaped equipment/cargo is far worse than a more symmetrical straight panel trailer in a headwind diagonal. Don’t believe me? Just watch a semi’s EGTs per same weight/cargo per weather winds. Higher the EGTs, the higher the fuel consumption. If wind speeds & directions stay constant, the ONLY way to conserve fuel usage is by decreasing throttle which decreases wind speed....... Or maybe add a few wind jammer shields to the rig? Oh and that 1980s flat faced semi rig averaging 5mpg would need $85,000 annual fuel budget today. |
They add Tenths, Not Miles per. Never done more than .1-.2mpg ever. Those claiming more are lying thru their teeth. We ran these programs of added wind deflector aero streamlining in the late 70s, again with engine improvements in the early 90s and last I saw was in early 2000s, NONE of which dependent of road conditions made a marginal rate of change with variables added into the formula. To gain Aerodynamic Value the Wind Speed would need be greater than 60mph Head On to a machine running over 60mph into that wind. Anything below 120mph combined produces a turbulence effect that removes any to all benefits of the devices. Any Engineer stating otherwise is attempting to prop Garbage Science.
Even in the 1970s/80s when COE Trucks were more popular, Lang nose conventionals out performed economically by 10-15%. Added sweeping sleeper roofs did little add economy to those models of truck. We did Wind Tunnel testing at McDonnell Aircraft in 1977, 1982, 1990. The company I worked for that did those tests was bought out by Penske, they Repeated those Wind Tunnel tests at Boeing in WA State in early 2000s, where the basic Low Speed of the machines was noted as the problem, NOTHING Below 120-130mph in the tunnels as to wind speeds changed any values for Aerodynamics. Turbulent Wind reactions to the machines in general was the rising concern.
Electronic Engines controls added close to FOUR MPG in the late 80s as CAT and Det Dsl made advances in electronic engine systems. Cummins was a Late Bloomer with Euro engines. More or less the introduction of Unit Injectors Cam Operated as on DD engines of the past with a electronically controlled rack was the key to fuel economy. EPA in a MINIMAL Benefit to a EXCESSIVELY Narrow margin of Health benefit ESTIMATIONS that have not ever been reviewed for validation, made fuels changes rules from Lo Sulphur Diesel then ULSD to make particulate improvements, Those failed where did NOT revert to older fuel formulas but added Restrictive exhaust systems adding to Parasitic HP Losses and economy drops against the already visualized BTU Value loss in those fuels. These Bandaid Formulae Wind Aerodynamics games have been played since the 1930s and do not amount to a hill of Horse Hockey. They are sponsored by and pressed by guess whom, EPA, the masters of JUNK Science.
Edited by DMiller - 10 Feb 2023 at 6:00am
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DMiller
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Posted: 10 Feb 2023 at 7:56am |
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Best evidence to support. Drive past a aero equipped semi, observe any flexible extension flaps, they will flutter not fold in the slip stream as that turbulent air occurs. Next look to water stain trails, uniform or scattered, rising or just flow across, then consider as on SUV or the old Station Wagons the effect of box extension on the rear of a trailer, inspect deposition of filth as the region becomes a low pressure zone. Turbulent air deposits the dirt randomly not flowing. Low pressure becomes a Sucking force, a speed brake.
Trucks in the greater part of operating are Slow Speed, under 45mph as a average unless cruising flatland super slab. Pulling grade max torque output nax fuel per hour, descending grade, speed controlled minimal fuel delivery to keep moving components lubricated yet speed still reduced. Delivery region, stop/go; transport zones IE metro regions, slowing accelerating, up and down shifting regardless auto or strictly mechanical.
Not wind tunnel steady state, that is a optimum 10-20% of travel function.
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DMiller
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Posted: 11 Feb 2023 at 5:37am |
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Final note on this, look at Europe, they do use sweptline roofs on their trucks yet the common body style is cabover, The few tenths of MPG does not offset the value of accessible maintenance and the roominess of their design cabovers as become a second home. Their roads in general do not provide for loner wheel base either and not redesigning highways for minor fuel economy raises.
Ours is the only nation humg up on hanging all this in the way garbage on trucks.
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Les Kerf
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Location: Idaho
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Posted: 11 Feb 2023 at 9:23am |
DMiller wrote:
...They add Tenths, Not Miles per. Never done more than .1-.2mpg ever. Those claiming more are lying thru their teeth...
...Electronic Engines controls added close to FOUR MPG in the late 80s as CAT and Det Dsl made advances in electronic engine systems. Cummins was a Late Bloomer with Euro engines. More or less the introduction of Unit Injectors Cam Operated as on DD engines of the past with a electronically controlled rack was the key to fuel economy...
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Fascinating stuff  When fuel gets to be $10+ they will be scratching to achieve .1-.2mpg, even if it means actually slowing down  But that isn't the American way. Pedal to the metal until we run out of fuel and off the cliff 
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DMiller
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Posted: 11 Feb 2023 at 11:35am |
Not really Les. Are a few idiots out there that slap the pedal to the floor and leave there, where most drivers NOT HERDERS know to Back Off and Out of throttle. I was managing over 6mpg out of the Western Star 24yd Quad Dump Truck issued me at my last employer. Detroit DD13 engine RT DLL08 trans and top end at 74mph. WOULD NOT, DID NOT push that speed, No Need. another driver they had, SAME TRUCK barely managed 5mpg, but was great on speedy with added trips for products.
All it really takes is Sense and Sensibility. A Semi geared for 78mph does NOT Have to be there all day every day. There is NOTHING placed in a semi truck shipment that would require that. My KW is currently geared for 80+, will it be placed there probably not ever as I do not need that kind of speed. Would I put a speed limit in the program of the ECM, NO CHANCE IN HE!!, as I can still use that added speed if Needed to go to pass and return to a reasonable after, same as any other machine out there. Know of autos as my Impala, V6, gets 24-26mpg on highway at rational speeds, drops to 22mpg if set cruise on 80 to stay with traffic. Wifes old Equinox, on a REALLY Good day would get 24 as that little four whapper was taxed to the max just to keep it moving.
Australian Semi's are predominantly Cabover, actually pull Trains of Trailers, aerodynamics have been tested there and do not amount to enough to change to anything else. Same holds true for US Railroads engines, about as streamlined as a Dulled face brick, little value for viability to aero those either. where Older engines as the E and F cabs or PA Series being Stream Lined were no better.
Edited by DMiller - 11 Feb 2023 at 11:36am
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