Finish line markings

[BaldyLochs]

I’ve been watching a lot of “vintage” NHRA footage lately (and loving the hell out of it mind you….). Got me wondering - When did they remove the X box paint at the finish lines? Was it when they cut down the pros to twelve thousand inches of racing surface? Guess I didn’t pay attention at the time.

 

[Pete]

I’ve been watching a lot of “vintage” NHRA footage lately (and loving the hell out of it mind you….). Got me wondering - When did they remove the X box paint at the finish lines? Was it when they cut down the pros to twelve thousand inches of racing surface? Guess I didn’t pay attention at the time.

I believe they changed most finish line markings when they moved the speed traps to 60' before the finish line instead of after.

 

[TSK]

Weren’t the old speed traps 60 ft before and 60 ft after the finish line?
Once NHRA quit recognizing speeds they removed the post finish line 60 ft portion and now measure speed from 60 ft before the finish line to the finish line.
Hence, no driving out the back door.

 

[PJ]

Weren’t the old speed traps 60 ft before and 60 ft after the finish line?
Once NHRA quit recognizing speeds they removed the post finish line 60 ft portion and now measure speed from 60 ft before the finish line to the finish line.
Hence, no driving out the back door.

yes they were 66ft before and after, this way the speed was truly what you were doing at the finish line. In an effort to curb speeds the changed to just before starting in 1989

 

[TSK]

yes they were 66ft before and after, this way the speed was truly what you were doing at the finish line. In an effort to curb speeds the changed to just before starting in 1989

Thanks PJ.

 

[Butch]

We can't talk about finish lines without mentioning this guy.

'Backdoor Bob' Struksnes

The life and times of Top Fuel racer Bob Struksnes

www.nhra.com

 

[T.Smith]

There was a time when the top speed holder of the weekend at the U.S. Nationals got a $500 bonus.

 

[Nunz]

There was a time when the top speed holder of the weekend at the U.S. Nationals got a $500 bonus.

That should be brought back, with a bigger number.

 

[PJ]

That should be brought back, with a bigger number.

except they don't want people chasing speed and outrunning tracks and/or tires. That's why the bonus points for the record went away

 

[Ramjet]

yes they were 66ft before and after, this way the speed was truly what you were doing at the finish line. In an effort to curb speeds the changed to just before starting in 1989

The 66 foot spacing before and after the finish line was because the total was 132 feet which was 1/10 of the total distance and that made the formula for the calculation easier. The problem with that was (is) that the calulation assumed (Break it down) that the speed was constant and measurement was by calculating the amount of time it took to go 132 feet and converted it to MPH. That was before 1989 and things have advanced to the point where the answer sometimes needs to go to at least four decimal places to be accurate for a record. When I was running at Bonneville I have data that I entered the Mile 2 to 2 1/4 - the exit showed 198.XXX MPH. At the Mile 3 Entrance it showed 298.XXX which gave an 1/2 way speed of 248.XXX. At the end of the 3 Mile the average was only 304.XXX but my air speed indicator exit speed showed 323 MPH which was accurate at all the other points. That means that there was acceleration during the timed space. The point is if you are accelerating the numbers are different than posted. For instance since they went to 1000 ft. is the trap now 50 feet (1/20th of the distance) two dragster or three F/C lengths. If so with the speeds they are going the numbers are calculated in milliseconds. Even though the timing equipment of course has advanced in technology and the fact that there are two machines shaking the earth with up to 22,00 HP bouncing tires up and down and maybe accelerating or even decellerating totally accurate measuring of Speed is a mammoth chore to be able to award money or even points that could convert to money.

 

[Cliff]

With the technology that is available now, why couldn't a "speed trap" be set up before & after the 1000' mark - but using, say 12 inches on each side. I'm just throwing this out as an example, no clue as to what length the trap should be. I know the MPH that is recorded is the speed before the finish line and that we haven't had a real finish line MPH in years. That has always irritated me "just cuz". I know that someone has run 300 in the 1/8th mile and 340 in 1000'. Would just like to see the real MPH. Well, at least we still get accurate ET.....

 

[TD5023]

With the technology that is available now, why couldn't a "speed trap" be set up before & after the 1000' mark - but using, say 12 inches on each side. I'm just throwing this out as an example, no clue as to what length the trap should be. I know the MPH that is recorded is the speed before the finish line and that we haven't had a real finish line MPH in years. That has always irritated me "just cuz". I know that someone has run 300 in the 1/8th mile and 340 in 1000'. Would just like to see the real MPH. Well, at least we still get accurate ET.....

If you were using 12" for the speed trap, going long of the finish line wouldn't be necessary. The difference would be minimal (my very rough calculations show that the reading for a 24" trap with the finish at the midpoint is about .07 MPH faster than a 12" trap ending at the finish for a car with a constant top fuel-level acceleration).

Like Roger said, the way it was done originally made sense for ease of calculation and we've just gradually worked our way to what we have now. There'd be no practical reason to do it this way if everything was blown up and restarted from scratch, but that's what we have and it's consistent wherever you go across all timing systems.

 

[Cliff]

Thanks Brad. That was just my wild hair.