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 Post Posted: Mon Sep 01, 2008 10:57 am 
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I was reading a few posts ,on another site. I was wandering when reaction time is started.  Normal staging, does it start when both staging lights are make "contact"? or is it when the staged beam makes contact?


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 Post Posted: Mon Sep 01, 2008 11:15 am 
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It is the time from when the green light engages till the cars tire leaves the beam.  i.e.  When staged, the beam is interrupted by your tire.  When launching the R.T. timer stops when the tire rolls forward enough that the final staging beam is no longer obstructed, when the sensor "eye" sees the beam again.

-Tanner

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 Post Posted: Mon Sep 01, 2008 1:12 pm 
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Reaction time is the difference in when the green comes on and the car leaves. If you're staged normally with both prestge and stage lights on it's when the prestage beam sees itself, if you're deep staged with the prestage light off, it's when the stage beam sees itself.

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 Post Posted: Mon Sep 01, 2008 1:31 pm 
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gearhead1011 wrote:
If you're staged normally with both prestge and stage lights on it's when the prestage beam sees itself, if you're deep staged with the prestage light off, it's when the stage beam sees itself.


I'm not sure I agree with this, and maybe I need to do some more reading up on this.  I don't believe the prestage beam will stop the timer.  If so, then how do you account for shorter reaction times when deep staged if it's reacting off two different beams?  I'm gonna do some reading so I'm not just guessing at this, but this doesn't sound right to me.  If it is, I'll stand corrected, by all means.

-Tanner

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 Post Posted: Mon Sep 01, 2008 2:05 pm 
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Deep or shallow staging does affect reaction times, but the RT timer starts at the green light and turns off when the stage beam (lower stage bulb) sees the beam (ie. tire is not blocking beam). Staging deep will shorten the rollout time before the car unblocks the stage beam making the RT shorter. I agree completely with Tanner.

The beam for pre-stage (upper) is only for the driver to help position his car and is not used for the timing system in any way.

Rick


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 Post Posted: Mon Sep 01, 2008 2:19 pm 
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It's funny, but I can't find any good technical data on any web searches I tried.  Nothing that goes into any real detail, anyway.

After thinking it over :-k  I'm going to stand by my previous statement.

-Tanner

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 Post Posted: Mon Sep 01, 2008 6:24 pm 
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Here is a link to a pretty good explanation. Seemed pretty good after a quick read thru. One thing that may be different, depending on the timing system, on some systems the Reaction timer is based on when the last yellow light comes on. This will show a .500 or .400 light as perfect and a .499 or .399 as red. Most of the newer systems show .000 as perfect and will show negative for red lights. The timer really would start at the last yellow either way, on the .000 based systems the timer will start at -.500 or -.400.

http://www.staginglight.com/guide/react.html

Here is a definition from the NHRA site.

NHRA site wrote:
Reaction time: the time it takes a driver to react to the green starting light on the Christmas Tree, measured in thousandths of a second. The reaction-time counter begins when the last amber light flashes on the Tree and stops when the vehicle clears the stage beam


The link is here:
http://www.nhra.com/basics/glossary.html

Rick


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 Post Posted: Mon Sep 01, 2008 7:51 pm 
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If the reaction time is displayed in the new format (.ooo is perfect)
The timer starts when the green comes on and is stopped when the stage beam is unbroken.

If the reaction is displayed in the old format (.500 is perfect) the timer starts when the third amber is on and stops when the stage beam is unbroken.


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 Post Posted: Mon Sep 01, 2008 8:50 pm 
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Scott Smith wrote:
If the reaction time is displayed in the new format (.ooo is perfect)
The timer starts when the green comes on and is stopped when the stage beam is unbroken.

If the reaction is displayed in the old format (.500 is perfect) the timer starts when the third amber is on and stops when the stage beam is unbroken.


How can it display the amount RED on redlights (negative) if it starts when the green comes on which is .000? It wouldn't be started yet if it starts at the green and couldn't read negative.

It starts at the last yellow, but is not zero based. The reaction timer starts at (note the negative signs) -0.500 or -0.400 at the last yellow and times up to zero and beyond in the positive direction.

Rick[/color]


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 Post Posted: Mon Sep 01, 2008 9:05 pm 
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Rick your correct but it was easier to explain the way I did it.
Don't forget the LB3A  ;-)


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 Post Posted: Mon Sep 01, 2008 11:09 pm 
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Tanner wrote:
gearhead1011 wrote:
If you're staged normally with both prestge and stage lights on it's when the prestage beam sees itself, if you're deep staged with the prestage light off, it's when the stage beam sees itself.


I'm not sure I agree with this, and maybe I need to do some more reading up on this.  I don't believe the prestage beam will stop the timer.  If so, then how do you account for shorter reaction times when deep staged if it's reacting off two different beams?  I'm gonna do some reading so I'm not just guessing at this, but this doesn't sound right to me.  If it is, I'll stand corrected, by all means.

-Tanner


I'm probably wrong on that.  I never deep stage so I was basing that comment on info I got from other racers.

Rick360 wrote:
Scott Smith wrote:
If the reaction time is displayed in the new format (.ooo is perfect)
The timer starts when the green comes on and is stopped when the stage beam is unbroken.

If the reaction is displayed in the old format (.500 is perfect) the timer starts when the third amber is on and stops when the stage beam is unbroken.


How can it display the amount RED on redlights (negative) if it starts when the green comes on which is .000? It wouldn't be started yet if it starts at the green and couldn't read negative.

It starts at the last yellow, but is not zero based. The reaction timer starts at (note the negative signs) -0.500 or -0.400 at the last yellow and times up to zero and beyond in the positive direction.

Rick[/color]


The reaction time is based on when the green comes on but I think the timer has to start when the tree is activated or when the 1st amber comes on not on the 3rd amber.  I know of people (I won't name names) that have left with the 1st or 2nd amber on and still got a reaction time.

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 Post Posted: Tue Sep 02, 2008 7:41 pm 
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Rick360 wrote:
Scott Smith wrote:
If the reaction time is displayed in the new format (.ooo is perfect)
The timer starts when the green comes on and is stopped when the stage beam is unbroken.

If the reaction is displayed in the old format (.500 is perfect) the timer starts when the third amber is on and stops when the stage beam is unbroken.


How can it display the amount RED on redlights (negative) if it starts when the green comes on which is .000? It wouldn't be started yet if it starts at the green and couldn't read negative.

It starts at the last yellow, but is not zero based. The reaction timer starts at (note the negative signs) -0.500 or -0.400 at the last yellow and times up to zero and beyond in the positive direction.

Rick[/color]


Interesting way to look at it. I have to agree somewhat. I guess it would have to count down from the top yellow.
Can you have over a 1 sec red?
I know if you leave before the tree starts, the time slip will have LBTA. Left Before Tree Activated.

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 Post subject: Think about this.
 Post Posted: Tue Sep 02, 2008 8:06 pm 
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Well, just think about it guys, when we are all on,  in our good days of racing, we cut great lights right?, ok, most of us probably stage a little shallow as to get the most distance to travel in, to compensate for our human reaction, and the vehicle reaction,  then we LEAVE BEFORE THE GREEN LIGHT COMES ON! RIGHT? so this proves that as we leave the stage beam only, this is when the timer starts, and stops per the electrical system, thus giving us our rt's...Does this make sense? does to me every time I cut a dbl 00 light!!! O:) and I may not understand electricity completely as long as I go GREEN and cut a good, and, win! =;  \:D/  \:D/  \:D/   my brain hurts from that one, let's move on to other things ok? =;   drag racin is great isn't it???? \:D/  \:D/  \:D/   ok, I'm done ;-)

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 Post Posted: Tue Sep 02, 2008 8:23 pm 
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I think the timer starts on the top bulb also. The stage light beam is the stopper of the timer.  =;

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 Post Posted: Tue Sep 02, 2008 9:00 pm 
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This is the definition from nhra web page and has alot to be desired. Leaves alot open for discusion. Like which is the last light?is it the last one lit or last one in the group from green?

](*,)  [-(  ](*,)  [-(


Qouted from the nhra page:
Reaction time:
         
 The reaction-time counter begins when the last amber light flashes on the Tree and stops when the vehicle clears the stage beam.

I take this as the prestage light turns off (starting the clock)and then when the staged light turns off (stoping the clock). Then the difference the computer calculates you left before or after the green light was turned on.


ps.... I come up with some stupid crap when I am bored don't I :-k


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