Unlimited Top Fuel (how quick & fast?)

[SAS]

Alan J. Said on a perfect run with no restictions , rev lim , rear ratio , with current motor and tires, about 4.25 at 350. Thats with perfect track and air.
Not hard to believe.

 

[FC138fan]

Might be a little problem with getting the engine to rev! Assuming that the circumference of the tire (before it blows) is approximately 12 feet, tire will be rotating 109.5 times per second. 109.5 rev/sec x 60 sec/min x rear end ratio of 2.7 (I think that's right) = 17,739 rpm - Feel free to check my math - I'm a little rusty.

Also, I believe drag increases as the square of speed. Have no idea how to do that math, but it's gotta be a REALLY big number -

I think your math is spot on. You have a great point, unless they can go into higher gears then they'd blow the engine.

I think your right about the air resistance deal too -

If someone alot smarter then me really looked into the physics, fluid dynamics, and mechanics of materials involved they would have a field day giving facts out on the ESPN broadcasts. It really is amazing even today how impressive these machines are.

I always find myself comparing the power in a TF engine to real life everyday situations: Ever stand next to a modern day 207 ton diesel electric locomotive? I think they run about 5,000 hp. Now take all that and pack it into 500 cubic inches.. then throw in another 3,000 hp. I wouldn't want to put that motor between my legs and then ride it over 300mph.

 

[Al smith]

Ive seen the rules change over the years, first no movable wing surfaces, no ground effect tunnels, no ground effect movable skirts that would compensate for tire growth. then no electronic clutch or fuel management. onto no vortex generators on wings, then wing size limit. then rear end gear rules including no overdrive transmissions, then multi speed blower not allowed. then nitro limit then timing retard. Just undoing all those rules above and including new cylinder heads and bore spacing. and a screw blower.


Hmmmm I wonder, 4:20s at 360?

 

[PJ]

What an opportunity to do some math!

I've heard a TF car can go from 0 to 100 mph in 0.8 seconds.

which equates to 0 to 147 ft / sec in 0.8 sec (183 ft per second squared)

-or- about 5.69 G's at the hit of the throttle (1G = 32.2 ft/sec^2)

lets assume you can maintain that for the full quarter (which they cant do just yet, but assume technology allows them to do that some day {we know the tires can handle it cause they are pulling that in the first .8 seconds today})

using the ol physics equation X = Xi +Vi T + 1/2 A T^2
X = 1320' (in this case)
Xi = 0' (initial position)
Vi = 0 (initial velocity)
T = time
A = acceleration (147 ft per second squared)

Solving for T we get a run in the quarter of 3.79 seconds

using the basic physics equation V = Vi T + 1/2 A T^2

knowing V = Velocity
Vi = 0 ft/sec Initial velocity
T = Time
A = Acceleration

Solving for V we get 1314 ft/sec

or about 896 miles per hour

So, if they could maintain 5.69G's through the entire run, theoretically they could have runs someday of:

3.79 seconds at 896 miles per hour.

Now if they can create a tire that can bond to the track better and not explode they could probably run faster.

Holy crap my eyes crossed reading that and now they're stuck

 

[The Counterfeiter]

[QUOTE=Nick Dobda;
If someone alot smarter then me really looked into the physics, fluid dynamics, and mechanics of materials involved they would have a field day giving facts out on the ESPN broadcasts. It really is amazing even today how impressive these machines are.

Spent some time with a TF crew chief during the NHRA Brownsburg shop tour day before last year's Indy 500. Got to adjust parameters with a laptop plugged into the car and received a very detailed fuel system lesson - including the mysterious slide valve! Very few fans could comprehend how complicated it is that these cars get down the track. That was a VERY cool day.

 

[Tim5636sc]

What an opportunity to do some math!

So, if they could maintain 5.69G's through the entire run, theoretically they could have runs someday of:

3.79 seconds at 896 miles per hour.

Now if they can create a tire that can bond to the track better and not explode they could probably run faster.

...so....that would be what exactly @ 1000'? Because 1320 will never happen again...

WHERE DO I SIGN UP TO TEST THIS EQUATION????

 

[PJ]

ok but if a train leaves Boston at 1pm going 72.5mph and then one leaves, LA at.....oh wait that won't work ummm


what about the flux capacitor?

 

[FC138fan]

...so....that would be what exactly @ 1000'? Because 1320 will never happen again...

WHERE DO I SIGN UP TO TEST THIS EQUATION????

I went to dig up my old physics book - here is a scan of the kinematic equations I used

Turns out I made a mistake! You will notice that velocity as a function of time is:

V = Vi + aT

!not!

V = Vi T + 1/2 A T^2

So T still equals 3.79 seconds (Displacement as a function of time)

BUT

V = 0 ft/sec + 183 (ft/sec^2) * 3.79 s = 694 ft/sec
-OR- 472 mi/hr

boy is my face red! I guess I should have dug out the book before I "recalled" that formula! (gosh I remember that happening all too often in that class)

FYI-

at 1000' T = 3.31 sec
V = 412 mi/hr

 

[FC138fan]

While we're on the subject, as luck would have it I stumbled on this question in the same physics book...

This one would require more thought - if nobody wants to solve it I can.. .however as for most questions in this book you can answer them with "who gives a S"

 

[DrRocket]

ok but if a train leaves Boston at 1pm going 72.5mph and then one leaves, LA at.....oh wait that won't work ummm


what about the flux capacitor?

Are we talking furlongs per fortnight here????

 

[Just Paul]

While we're on the subject, as luck would have it I stumbled on this question in the same physics book...

This one would require more thought - if nobody wants to solve it I can.. .however as for most questions in this book you can answer them with "who gives a S"

Cool shot of "Diamond Dave"

 

[Toby]

Here is a run from 2000 in a Top Fuel car I worked on. Its definitely not our best run, yet its the only run I could find on this laptop. It is a 4.61 pass at 316.30. The purple trace is inline accel, tan is engine rpm and the blue is driveshaft rpm.
Data

 

[Leebone]

896 Miles Per Hour???

I've never witnessed or heard a sonic boom at a dragstip before. I'd like to experience that. How do I get tickets for that?

 

[FC138fan]

Here is a run from 2000 in a Top Fuel car I worked on. Its definitely not our best run, yet its the only run I could find on this laptop. It is a 4.61 pass at 316.30. The purple trace is inline accel, tan is engine rpm and the blue is driveshaft rpm.
Data

The purple line is what I don't understand. Notice how it peaks out early and then tapers down to less then 1G towards the end. What's the explanation for that? If you could get that purple line to be horizontal at 5.5 or whatever you could get the 3.79 s at 472 mi/hr

 

[BrettV]

The purple line is what I don't understand. Notice how it peaks out early and then tapers down to less then 1G towards the end. What's the explanation for that? If you could get that purple line to be horizontal at 5.5 or whatever you could get the 3.79 s at 472 mi/hr

Drag. As Jim said, drag is proportional to the square of velocity - at least at sub-sonic speeds!

 

[Horsepower & Heels]

My brain hurts now trying to follow all that.

Math=kryptonite. YUCK!

 

[Porkchop]

low 4.30's around 345

 

[Dubs]

Here is a run from 2000 in a Top Fuel car I worked on. Its definitely not our best run, yet its the only run I could find on this laptop. It is a 4.61 pass at 316.30. The purple trace is inline accel, tan is engine rpm and the blue is driveshaft rpm.
Data

What happen to the engine RPM at about 3.2 seconds?

 

[Al smith]

What happen to the engine RPM at about 3.2 seconds?

looks like the floaters and disks are welding themselves together there

 

[JL]

How about this... Solid rubber tires but instead of using the tires to gain traction, hook them to a rail. Utilize some type of system to grab the rail and accelerate. Crazy, yes, but unlimited means unlimited...