Actually it's a reasonable thing to do, draft a semi for a mile per gallon and risk everyone's health on the road around you. Your fellow travelers would appreciate known you put them at risk to safe a couple of bucks.
Drafting Tractor Trailers for mpg gains.
- Thread starter Best F100
- Start date
- Status
- Joined
- Sep 28, 2002
- Messages
- 39,798
Try the window thingy just to prove it to yourself (or disprove it).
Quote:
What do you call a car that drafts a semi?
A bumper sticker
Or "paste".
The laws of physics can't be repealed or bargained with, and it takes you measurable time to stop. If you're too close to the big rig when he slams on his brakes . . .
I wish some of the geniuses who tailgate much larger vehicles at speed *would* remove themselves from the gene pool, but they've probably already bred. Too bad.
I go the other way on this - don't try to max anything here but safety .
This means maximising all aspects of separation including fore and aft .
( Try to do the fuel economy thing most of the other ways possible . )
It also means extending to others I think , (ultimately self serving as well) , 'courteous' driving and positioning - esp. to the class 8 guys .
Of the hundreds of 'silly' things you see on the road how they get treated is sometimes just unreal - and real 'dumb' .
This means maximising all aspects of separation including fore and aft .
( Try to do the fuel economy thing most of the other ways possible . )
It also means extending to others I think , (ultimately self serving as well) , 'courteous' driving and positioning - esp. to the class 8 guys .
Of the hundreds of 'silly' things you see on the road how they get treated is sometimes just unreal - and real 'dumb' .
Seriously, this will probably draw the wrath of many of you here, but you don't need to be THAT close to benefit from the reduced wind resistance. It can be done in a safe distance. You can feel it... once you enter the zone the car begins to glide a little easier. At the distance you 'enter the zone' you're still more than 100 feet back in most instances, more than most cars give each other in day-to-day driving.
The problem indeed is all the little rocks that will get thrown up at you. In Idaho this is a real problem because they use gravel instead of salt to keep the road "safe" in the winter (don't get me started...). The other problem is finding a rig that wants to travel the same speed that you want to travel. I don't have the patience to practice this for more than a few minutes at a time.
The problem indeed is all the little rocks that will get thrown up at you. In Idaho this is a real problem because they use gravel instead of salt to keep the road "safe" in the winter (don't get me started...). The other problem is finding a rig that wants to travel the same speed that you want to travel. I don't have the patience to practice this for more than a few minutes at a time.
- Joined
- Sep 28, 2002
- Messages
- 39,798
For some odd reason the thrust of this thread is an attempt to convince you that you are totally incapable of stopping faster than an semi in a passenger car. Like I said "odd". There's also the insistence that regardless of whatever distance you are from the rear of a semi .it's automatically too close if you're getting the advantage of being in their vacuum.
Now if you like to day dream and don't take the least bit of your driving seriously or are sight seeing...then sure..don't tempt fake by being a lamebrain and an idiot at the same time.
There's plenty of high density/high speed traffic with mixed company that all of you, unless you're retired and can pick and choose your travel times, ..MUST encounter. I assume that you're all capable of navigating it without issues. Semis tailgate each other closer than is needed for being inside the vacuum envelope.
Obviously the risks wouldn't worth for an mpg or two but look at Gary's instance, it is a whole 6mpg! So I had been tried this a couple of times to see what happens.
Seriously... I think if there is an air wave created there should be cascades of "envelopes" following, though gradually diminishing. In my case it also wasn't a tailgate distance but slightly closer than the here-legal 2 secs distance I must say. I don't know which wind I catched behind a inter-city bus but it was as obvious as wheteher driving with a 20w 50 or 10w 30 at the same spot.
BTW... take the bus. Their speed and track are more stable, and in the event, they have a more sane bumper level. Trucks are a no-no for me. I don't get close to them even at the toll booths and if it's not downhill they do can brake suddenly like a car.
Seriously... I think if there is an air wave created there should be cascades of "envelopes" following, though gradually diminishing. In my case it also wasn't a tailgate distance but slightly closer than the here-legal 2 secs distance I must say. I don't know which wind I catched behind a inter-city bus but it was as obvious as wheteher driving with a 20w 50 or 10w 30 at the same spot.
BTW... take the bus. Their speed and track are more stable, and in the event, they have a more sane bumper level. Trucks are a no-no for me. I don't get close to them even at the toll booths and if it's not downhill they do can brake suddenly like a car.
- Joined
- Sep 28, 2002
- Messages
- 39,798
Keep in mind my vehicles of choice are a minivan or a jeep. Alhtough the minivan isn't a total brick like the jeep, it's hardly any econo appliance in terms of coefficient of drag (2nd Gen Caravan). The jeep is just "rude" in terms of aerodynamics. They both sit high, relatively speaking. 17+ mpg is not abnormal for my 4 cylinder 2.5 liter engine with automatic at highway speeds. It's capable of 20+ in suburban environments at speeds around 45-50. Naturally this means a long trip if you're going cross country.
I don't see the "risks" at all. As I said, this is par for the course at a given traffic density at the same speeds. If you aren't participating, you're a rolling barricade to traffic on the road (4 lane). Every on ramp is a slow down ..to be followed by a mass return to light speed. I can't see this being just a "Phila area" thing.
Any "safe" following distance is filled with other traffic. Safe following distances are what those entering the roadway view as opportunity (and it is).
I don't see the "risks" at all. As I said, this is par for the course at a given traffic density at the same speeds. If you aren't participating, you're a rolling barricade to traffic on the road (4 lane). Every on ramp is a slow down ..to be followed by a mass return to light speed. I can't see this being just a "Phila area" thing.
Any "safe" following distance is filled with other traffic. Safe following distances are what those entering the roadway view as opportunity (and it is).
I'm with Gary Allen, crw, Palut and others that attempt to benefit aerodynamically from other vehicles on the road, especially larger ones like tractor-trailers.
Lonnie's posts are funny ... and have a lot of truth to them ... but I think he overstates his case in the interest of humor. I can't say how far behind a truck or bus I'll follow (~75'+ or so?) but it isn't nearly as close as I am forced to follow in heavy traffic. And, I won't even attempt drafting of any kind in cold weather because of the debris large vehicles kick up.
You can only successfully 'draft' on the open road, with light-to-medium traffic. Following other vehicles in heavy traffic is difficult and can lead to tapping the brake ... which will quickly cancel-out all your aerodynamic gains.
Following other vehicles using the 2.5 second rule?? Where do you live? During the morning commute on highways I no longer have to drive on
you would see packs of dozens (even hundreds) of cars moving at 70+mph spaced just 50' or so from each other. It's impossible to avoid that around here if you have a significant commute during 'normal' work hours.
Another thing I like about pacing myself with another driver is that I am not tempted to gradually increase my speed as I look out my windshield at an open road ... especially after driving most of the day. Yes, I have cruise control but hate using a crutch that inspires inattentiveness on long drives. Also, cruise control is probably a gas saver for the average driver, but if you know what you are doing, you can let yourself build up speed going down hills and lose speed going up to save the most (keeping load light on the motor all the while).
Mythbusters explored this issue using ... at 55mph they gained over 40% greater fuel economy travelling a ridiculous 10 feet behind an 18-wheeler in a controlled test using a Dodge Charger. BUT, they found that measurable savings happen at much greater following distances. I myself will follow much smaller vehicles including minivans, SUVs, pick-ups, etc ...
You'll find drafting and other fuel savings tips discussed as "hypermiling." Google the term and read. My 2006 Civic (conventional 1.8L engine) has fewer than 10,000 miles on the odometer but I can regularly get 40+ mpg in mixed driving using some 'hypermiling' techniques.
Lonnie's posts are funny ... and have a lot of truth to them ... but I think he overstates his case in the interest of humor. I can't say how far behind a truck or bus I'll follow (~75'+ or so?) but it isn't nearly as close as I am forced to follow in heavy traffic. And, I won't even attempt drafting of any kind in cold weather because of the debris large vehicles kick up.
You can only successfully 'draft' on the open road, with light-to-medium traffic. Following other vehicles in heavy traffic is difficult and can lead to tapping the brake ... which will quickly cancel-out all your aerodynamic gains.
Following other vehicles using the 2.5 second rule?? Where do you live? During the morning commute on highways I no longer have to drive on
Another thing I like about pacing myself with another driver is that I am not tempted to gradually increase my speed as I look out my windshield at an open road ... especially after driving most of the day. Yes, I have cruise control but hate using a crutch that inspires inattentiveness on long drives. Also, cruise control is probably a gas saver for the average driver, but if you know what you are doing, you can let yourself build up speed going down hills and lose speed going up to save the most (keeping load light on the motor all the while).
Mythbusters explored this issue using ... at 55mph they gained over 40% greater fuel economy travelling a ridiculous 10 feet behind an 18-wheeler in a controlled test using a Dodge Charger. BUT, they found that measurable savings happen at much greater following distances. I myself will follow much smaller vehicles including minivans, SUVs, pick-ups, etc ...
You'll find drafting and other fuel savings tips discussed as "hypermiling." Google the term and read. My 2006 Civic (conventional 1.8L engine) has fewer than 10,000 miles on the odometer but I can regularly get 40+ mpg in mixed driving using some 'hypermiling' techniques.
OK, I think the one-way roads are the best single safety device, relative speed is what counts, and even the close tailgating usually ends up with only property damage. Here we have the similar problem, might be worser. I see collisions on my daily ~95 mile trip but can't remember one with injuries. I like the buses b'cause they act as regulators... cars don't cut in front of them as closely, and they leave some space in front at any cost (eh...
) so no abrupt braking. Once it turns to a stop-and-go left lane goes just spastic while the middle bus lane(s) slow-and-go with the same average speed. But I fear the dump trucks and some trailers where the only safety device is the A pillars, this particular thing hasn't been solved by the one-way roads i think.
Ya you could. @ 60mph a 80K truck @ 60mph takes 540ft to stop if all the brakes are adjusted correctly, no air leaks etc.
- Joined
- Sep 28, 2002
- Messages
- 39,798
Quick poll here. How many people who are saying (basically) "don't drive behind a semi" (you'll shoot your eye out, kid) are also truck drivers?? If any of you are, do any of you think that you're just saying (again, basically) "I don't like anyone tailing me ..at any distance"?? I surely have no problem with this disposition.
Gary,
Every vehicle needs to surround itself with a "space cushion". Please Google "The Smith System" which is a great driver tool handed out to your premiere fleets (those that really care). I've had people tail-gate me for hours on end and it always turns out to be someone with no understanding of simple physical laws of the universe. I watch these unfortunate souls go from tail-gating me to another vehicle?? I watch in amazement as people with really nice cars (leased?) who follow close to low-beds and dump trucks as old dried mud and stones bounce off of their rides. No tool can shake off everybody but I just keep tapping down on my cruise lever 3 times, then wait a while and keep this cycle until they come out of their trance. I do long for a message board mounted on the rear so I could politely awaken these souls to their danger. Not slighting here but it invariabbly is young women... sorry thats just a fact. Take it from me as I've seen many stunts pulled by others, give a large truck all the room it needs as these guys may have been awake for days and might (will) behave erratically at times.
Every vehicle needs to surround itself with a "space cushion". Please Google "The Smith System" which is a great driver tool handed out to your premiere fleets (those that really care). I've had people tail-gate me for hours on end and it always turns out to be someone with no understanding of simple physical laws of the universe. I watch these unfortunate souls go from tail-gating me to another vehicle?? I watch in amazement as people with really nice cars (leased?) who follow close to low-beds and dump trucks as old dried mud and stones bounce off of their rides. No tool can shake off everybody but I just keep tapping down on my cruise lever 3 times, then wait a while and keep this cycle until they come out of their trance. I do long for a message board mounted on the rear so I could politely awaken these souls to their danger. Not slighting here but it invariabbly is young women... sorry thats just a fact. Take it from me as I've seen many stunts pulled by others, give a large truck all the room it needs as these guys may have been awake for days and might (will) behave erratically at times.
Could you alter the cars resistance to air flow (the way the Americas cup yachts have special polymer coatings to make them more slippery) by say ionisong the skin of the vehicle with a charged particle effect such that you create a negative charge at the front and a positive ion charge at the rear - creating in effect a vacuum into which the car slips because of the positive charge at the rear pushing it and the reduced pressure in front pulling it!
This way you don't need a tractor trailer out front!
You use polasmoidal induction to achieve this effect!
First you would have to accept my postulate that indeed Albert Einstein was fundamentally WRONG when he suggested his Special theory of relativity!
Albert Einstein - a Nobel Prize winnner in Physics for his photoelectric effects paper!
Yet - no one remembers him for that, his legitimate claim to fame, instead today everyone remembers him for a non peer reviewed paper that somehow got published despite it's obvious basic & fundamental errors, that today any 14 year old kid could point out - if it werent for the fact they are indoctrinated at school with incorrect / flawed physics!
E=MC^2 is what Albert is famous for, Energy = Mass Times the Universal Constant C (speed of light) squared! The so called "theory of relativity"!
Everyone knows this yet, it is patently WRONG, and easily disprovable!
Here I'll do it for you - just so you don't think I'm pulling your leg!
If I ask you the square root of 4 - most of you here would answer 2
You'd be correct!
A FEW 14 year olds who'd just compeleted a certain level of mathematics tuition however, would give two asnwers!
Square root of 4 = 2 and (negative) -2
Thats right, the negative root squared, equals a positive result!
-2 x -2 = +4
Most of us forget that bit!
Guess what - so did Albert Einstein! (And almost everyone whos come after him!).
E = MC^2
Speed of light C (in a vacuum) used to be considered roughly 186000miles per second
These days of metrics it's expressed as 3 x 10^8 meters / second
When we square it we get 9 x 10^16 meters/second & thats the value of C squared!
Only one little "overlooked" problem with Albert E's much vaunted relativity theory!
-3 x 10^8 squared ALSO = 9 x 10^16!
Yes - the speed of light in Albert Einsteins FAMOUS THEORY OF RELATIVITY theorem can be both positive (travelling in one direction) or negative (travelling in the opposite direction) AT THE SAME TIME and STILL make his theorem true!
Don't try that at home folks (going in two opposite directions at the same time) unless you want to rip yoursleves a new butt hole!
So, what can we infer from this conundrum?
The usual problem with producing a hypothesis based on a "false" premise is a paradoxical result.
For example:-
(1) All dogs have four legs,
(2) All four legged animals are cats.
Therefore:
All dogs are cats,
AND/OR
All cats are dogs!
Which premise is false?
With the Special Theory of Relativity, the resulting paradox, was called the "twin paradox" along with several others which were discovered later.
So - the point of all this? We really do NOT yet fuly understand science and physics as well as we believe!
I'll give you another special theory of relativity!
Plasmoidal induction - and the speed of light equals infinity (the ONLY value for C that makes Albert E's forumla true!).
So much yet to learn hey!
Cheers!
This way you don't need a tractor trailer out front!
You use polasmoidal induction to achieve this effect!
First you would have to accept my postulate that indeed Albert Einstein was fundamentally WRONG when he suggested his Special theory of relativity!
Albert Einstein - a Nobel Prize winnner in Physics for his photoelectric effects paper!
Yet - no one remembers him for that, his legitimate claim to fame, instead today everyone remembers him for a non peer reviewed paper that somehow got published despite it's obvious basic & fundamental errors, that today any 14 year old kid could point out - if it werent for the fact they are indoctrinated at school with incorrect / flawed physics!
E=MC^2 is what Albert is famous for, Energy = Mass Times the Universal Constant C (speed of light) squared! The so called "theory of relativity"!
Everyone knows this yet, it is patently WRONG, and easily disprovable!
Here I'll do it for you - just so you don't think I'm pulling your leg!
If I ask you the square root of 4 - most of you here would answer 2
You'd be correct!
A FEW 14 year olds who'd just compeleted a certain level of mathematics tuition however, would give two asnwers!
Square root of 4 = 2 and (negative) -2
Thats right, the negative root squared, equals a positive result!
-2 x -2 = +4
Most of us forget that bit!
Guess what - so did Albert Einstein! (And almost everyone whos come after him!).
E = MC^2
Speed of light C (in a vacuum) used to be considered roughly 186000miles per second
These days of metrics it's expressed as 3 x 10^8 meters / second
When we square it we get 9 x 10^16 meters/second & thats the value of C squared!
Only one little "overlooked" problem with Albert E's much vaunted relativity theory!
-3 x 10^8 squared ALSO = 9 x 10^16!
Yes - the speed of light in Albert Einsteins FAMOUS THEORY OF RELATIVITY theorem can be both positive (travelling in one direction) or negative (travelling in the opposite direction) AT THE SAME TIME and STILL make his theorem true!
Don't try that at home folks (going in two opposite directions at the same time) unless you want to rip yoursleves a new butt hole!
So, what can we infer from this conundrum?
The usual problem with producing a hypothesis based on a "false" premise is a paradoxical result.
For example:-
(1) All dogs have four legs,
(2) All four legged animals are cats.
Therefore:
All dogs are cats,
AND/OR
All cats are dogs!
Which premise is false?
With the Special Theory of Relativity, the resulting paradox, was called the "twin paradox" along with several others which were discovered later.
So - the point of all this? We really do NOT yet fuly understand science and physics as well as we believe!
I'll give you another special theory of relativity!
Plasmoidal induction - and the speed of light equals infinity (the ONLY value for C that makes Albert E's forumla true!).
So much yet to learn hey!
Cheers!
Why would you want to drive slowly enough to draft a tractor trailer?
Why would you allow a rig to tailgate you, since it can't keep up with the slowest car?
Why would you allow a rig to tailgate you, since it can't keep up with the slowest car?
Never in my 42 years of life have I ever seen or heard of such a thing.
I would think enough marbles would cause the car to go int a skid.
When I was about 23 years old, I was going south on I-75 at night and drafted a semi. The driver was not pleased and to express his displeasure, he locked up his brakes on me. After that I slowed down until I lost sight of him and have never drafted a semi again.
When I was about 23 years old, I was going south on I-75 at night and drafted a semi. The driver was not pleased and to express his displeasure, he locked up his brakes on me. After that I slowed down until I lost sight of him and have never drafted a semi again.
- Joined
- Sep 28, 2002
- Messages
- 39,798
Well, I'd say that it's rude to be too close to anyone. I'll try and guesstimate the distance when I'm inside the envelope on my next highway excursion. It's not that close ..really. Certainly not anything outside the ordinary (or rather, typical) at a certain density of traffic. Traffic travels in "packs". Very few loners out there.
I agree that I wouldn't necessarily want a "tail" ..but in many instances you can take your pick of who's going to be in that spot ..purposely tailing you or otherwise.
I agree that I wouldn't necessarily want a "tail" ..but in many instances you can take your pick of who's going to be in that spot ..purposely tailing you or otherwise.
We took a trip to AZ a couple of years ago, pulling our 16' Scamp camper with my Jeep Wrangler (4.0 six and auto). Heading south through NE and KS we ran into some strong head-winds and I could only manage about 54 mph on the interstate at wide open throttle. Every time a semi passed us and pulled in front of us, I had to let up substantially on the gas peddle to maintain my speed. I finally matched my speed to one of those trucks and followed him about 30 feet behind for maybe 10 miles or so, just to get a break from that head wind! As a former truck driver, I didn't like being there, but that break from the head wind sure felt good!
Back when the speed limit was 55, I was headed north to Winnipeg on I-29 wit a load of feed corn doin' about 60 at night, when a guy in a car pulled about 10 feet behind me and shut off his headlights and just left his parking lights on! Couldn't believe that idiot! I was still debating what to do with that fool when another semi doing about 65 passed us both. Guess what? On went the headlights, and he pulled out behind the other truck, snuck up behind him, and turned of his headlights again. And away they went!
Back when the speed limit was 55, I was headed north to Winnipeg on I-29 wit a load of feed corn doin' about 60 at night, when a guy in a car pulled about 10 feet behind me and shut off his headlights and just left his parking lights on! Couldn't believe that idiot! I was still debating what to do with that fool when another semi doing about 65 passed us both. Guess what? On went the headlights, and he pulled out behind the other truck, snuck up behind him, and turned of his headlights again. And away they went!
- Status
Similar threads
