Question for those with nav
Active Enthusiast
Joined: Jan 2006
Posts: 221
Re: Question for those with nav
Close, but not quite.
Drafting off a car in front, reduces wind load on the car in back... thus the car in back is no longer operating at maximum horsepower. It saves the car in back gasoline, and also gives him more "headroom" ( his foot is no longer to the floor, while the car in front is ) to accelerate and pass when the time is right.
I don't know why this is so difficult to understand.
Drafting off a car in front, reduces wind load on the car in back... thus the car in back is no longer operating at maximum horsepower. It saves the car in back gasoline, and also gives him more "headroom" ( his foot is no longer to the floor, while the car in front is ) to accelerate and pass when the time is right.
I don't know why this is so difficult to understand.
The truck breaks the wind so the car behind has less air pressure in front reducing drag and improving mpg. What also happens is:
1: Nothing significant occurs behind the truck to change anything for the truck, so it is a free ride for the car in back with no cost to the truck.
2: The car fills in some space in behind the truck that would have been negative pressure, so the car helps the truck by putting some of the vaccum behing it instead of the truck. Both the truck and car win.
3: The car messes up the air flow behind the truck increasing the vacuum behind the truck, so the gain to the car is the truck's pain.
I doubt that we can't figure this out without some input from some truckers. Any FEH owners drive a truck?
rcomeau
Ridiculously Active Enthusiast
Joined: Mar 2006
Posts: 1,401
Re: Question for those with nav
Until one of us builds a wind tunnel we can keep discuss until the cows come home. The 3 theories are (as I understand them):
The truck breaks the wind so the car behind has less air pressure in front reducing drag and improving mpg. What also happens is:
1: Nothing significant occurs behind the truck to change anything for the truck, so it is a free ride for the car in back with no cost to the truck.
2: The car fills in some space in behind the truck that would have been negative pressure, so the car helps the truck by putting some of the vaccum behing it instead of the truck. Both the truck and car win.
3: The car messes up the air flow behind the truck increasing the vacuum behind the truck, so the gain to the car is the truck's pain.
I doubt that we can't figure this out without some input from some truckers. Any FEH owners drive a truck?
rcomeau
The truck breaks the wind so the car behind has less air pressure in front reducing drag and improving mpg. What also happens is:
1: Nothing significant occurs behind the truck to change anything for the truck, so it is a free ride for the car in back with no cost to the truck.
2: The car fills in some space in behind the truck that would have been negative pressure, so the car helps the truck by putting some of the vaccum behing it instead of the truck. Both the truck and car win.
3: The car messes up the air flow behind the truck increasing the vacuum behind the truck, so the gain to the car is the truck's pain.
I doubt that we can't figure this out without some input from some truckers. Any FEH owners drive a truck?
rcomeau
Hybrid and Ethanol Expert
Joined: Mar 2005
Posts: 3,616
From: All over the Central U.S.
Re: Question for those with nav
I used to teach High School science and industrial arts ( aka "shop" ).
We had a 24" x 24" x 8 foot long wind tunnel for testing models.
We focused most classroom time on aircraft designs.
But I can tell you #1 is the correct answer.
Not because we tested models of cars behind semis, but because I have a firm understanding of aerodynamics.
While I don't play one on TV, I'm doing my best to be a mythbuster right here.
-John
We had a 24" x 24" x 8 foot long wind tunnel for testing models.
We focused most classroom time on aircraft designs.
But I can tell you #1 is the correct answer.
Not because we tested models of cars behind semis, but because I have a firm understanding of aerodynamics.
While I don't play one on TV, I'm doing my best to be a mythbuster right here.
-John
Active Enthusiast
Joined: Jan 2006
Posts: 221
Re: Question for those with nav
I used to teach High School science and industrial arts ( aka "shop" ).
We had a 24" x 24" x 8 foot long wind tunnel for testing models.
We focused most classroom time on aircraft designs.
But I can tell you #1 is the correct answer.
Not because we tested models of cars behind semis, but because I have a firm understanding of aerodynamics.
While I don't play one on TV, I'm doing my best to be a mythbuster right here.
-John
We had a 24" x 24" x 8 foot long wind tunnel for testing models.
We focused most classroom time on aircraft designs.
But I can tell you #1 is the correct answer.
Not because we tested models of cars behind semis, but because I have a firm understanding of aerodynamics.
While I don't play one on TV, I'm doing my best to be a mythbuster right here.
-John If I were a betting man, I would pick 1 as well, particularly if you are at a safe and polite distance (3 sec behind).
Cheers,
rcomeau
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