Top fuel facts

[KA-T_240]

inspector01;290567 wrote:
You didn't do very good in math and phyiscs did you?? If a top fuel dragster averages 190mph, and the other car averages 200 mph over the course, the car will obviously win. Top speed, low speed, etc, don't matter at all, if the average speed is faster.

If a top fuel dragster can do the full run(reaction time and E.T.) in under 4.5 secs, then it could possibly win. But simple math says that if the car goes 200mph (again, no acceleration) the whole way, it will take 4.5 secs, so they have to beat that.

What if the car is accelerating?

[inspector01]

KA-T_240;290569 wrote:
What if the car is accelerating?

Then the time would go down, you would need to knows its average speed, or rate of acceleration, etc to figure it out. That is why 4.5 secs is the minimum. Assuming it accelerated to say, 220 mph, it would bring down the ET to less than 4.3 seconds.

[SPANISH-RICE]

Top fuel doesnt run quarter mile

[63vette]

inspector01;290567 wrote:
You didn't do very good in math and phyiscs did you?? If a top fuel dragster averages 190mph, and the other car averages 200 mph over the course, the car will obviously win. Top speed, low speed, etc, don't matter at all, if the average speed is faster.

If a top fuel dragster can do the full run(reaction time and E.T.) in under 4.5 secs, then it could possibly win. But simple math says that if the car goes 200mph (again, no acceleration) the whole way, it will take 4.5 secs, so they have to beat that.

If the first car enters the "course" at 200mph and remains at that speed, its average is 200, the TDF car started at 0 at the beginning of the 1/4 pass at the exact time the first car tripped the beam then accelerated to 335mph in the 1/4 mile so its average would be substantially lower and 190 is probably close. The TFD car is capable of 4.437 so the TFD car would win if it runs a good pass.

[inspector01]

63vette;290574 wrote:
If the first car enters the "course" at 200mph and remains at that speed, its average is 200, the TDF car started at 0 at the beginning of the 1/4 pass at the exact time the first car tripped the beam then accelerated to 335mph in the 1/4 mile so its average would be substantially lower and 190 is probably close. The TFD car is capable of 4.437 so the TFD car would win if it runs a good pass.

And that is basically what I said, the TFD would have to run faster than 4.5 secs total to have a shot at beating the other car, especially if the other car accelerated. Reaction time has to be included too, but yes, with a perfect run, it would have a chance, even that would not be a "whooping" tho.

And the TFDs average speed would have to be higher than the cars to win, no matter what its low or top speed. So 190 mph average speed could never win.

[capitlj]

I did catch that and thats why I posted again. The 190 mph average is something else that was on the NHRA website but that doesn't sound right since they cover 1000 feet, the length of their races since Kalitta's crash, in less than 4 seconds at around 315. In a full 1/4 mile drag they can hit almost 340. The current NHRA 1/4 mile record is 4.42. So yes a 200 mph flying start might be enough to beat a top fuel car. Even though they can be going over 280mph at the 660 foot mark. I still want to see it on mythbusters.

[Gundar1]

Fact: Nitromethane messes your shit up!

[SPANISH-RICE]

gundar1;290841 wrote:
fact: Nitromethane messes your shit up!

truth^

good god that stuff is harsh

[zbrown]

inspector01;290567 wrote:
You didn't do very good in math and phyiscs did you?? If a top fuel dragster averages 190mph, and the other car averages 200 mph over the course, the car will obviously win. Top speed, low speed, etc, don't matter at all, if the average speed is faster.

If a top fuel dragster can do the full run(reaction time and E.T.) in under 4.5 secs, then it could possibly win. But simple math says that if the car goes 200mph (again, no acceleration) the whole way, it will take 4.5 secs, so they have to beat that.

63vette;290574 wrote:
If the first car enters the "course" at 200mph and remains at that speed, its average is 200, the TDF car started at 0 at the beginning of the 1/4 pass at the exact time the first car tripped the beam then accelerated to 335mph in the 1/4 mile so its average would be substantially lower and 190 is probably close. The TFD car is capable of 4.437 so the TFD car would win if it runs a good pass.

NO NO, dont bring math into this, it is totally irrelevant and doesn't apply to real life

sarcasm,.................. I love when people argue against simple math, it is rather funny

[capitlj]

Zach that kind of arguement is not going to get this on mythbusters, step it up guy.

[thrash]

the average velocity is nothing more than the change in velocity over the change in time. in the case of a standing start at t0, it's as simple as dividing trap speed by seconds.

here's a fun experiment! supposing that i need to go 1320 feet, and i do it in 4.5 seconds, what is my average velocity?

1320 / 4.5 = 293.333

293.333 is a funny number in a funny unit - its in feet per second.

so we figure there are 5280 ft in a mile and 3600 seconds in an hour, and we see that to go from FPS to MPH we divide the FPS value by (5280/3600).

If you cut a 4.5 second quarter mile, your average speed was 293.33 fps or 200 MPH, dead on.

If you cut a 4.0 quarter mile, your average speed was 225 mph.
here are the values in seconds, fps, and mph, for the spread between a 4.0 ET and a 4.5 ET, in .1s increments:

4.0 - 330 - 225
4.1 - 321.9 - 219.5
4.2 - 314 - 214
4.3 - 306.9 - 209
4.4 - 300 - 204
4.5 - 293.333 - 200

if we know the time, and that we had a standing start, what can we say about the trap speed?

Well, we cannot say anything definitively. If the change in velocity were constant (ps: the change in velocity is acceleration, and the change in a function over time is known as its "derivative", thus acceleratoin is the derivative of velocity..), then the acceleration at t(x) would be a simple line. (when f'(x) is constant, f(x) is linear)

One would expect that at the half way point, the car would have instantaneously acheived its "average" velocity. It spent the first half of the run going slower than average, and will spend the final half of the run going faster than average.

So in the constant-acceleration case with a 200 mph average speed, the start speed is 0 and the trap speed must therefore be 400mph.

The ending velocity, in fps would be 586.6 fps, and it was acheived in 4.5S, for a constant acceleration of just over 130f feet per second "squared" (per second "squared" are the units of acceleration)

Acceleration due to earth Gravity in the FPS system is about 32 fps^2, and so the 4.5s constant-acceleration standing start run is 4.074Gs for its entire duration.

Since a top fuel car does not trap at 400mph, and it also finishes the run in under 4.5s, we can say that is average acceleration is actually higher than 4G. We can also say that it's average speed is higher than 200 mph, with the majority of the acceleration front-loaded into the first half of the run.

This intuitively makes sense -- every ground vehicle has higher acceleration at lower speeds than it does at higher speeds, if for no other reason than work-required to overcome aerodynamic drag increases with the square of velocity.

The short version is this:
if you finish the quarter in under 4.5 seconds, your average velocity was higher than 200mph, and your average acceleration was higher than 4 Gs. No exceptions.

[capitlj]

That's more like it.