Hey Magnethead or Nitro Dude or any other dragracers out there?
I have a question about the start and finish line timing in drag racing. From my limited knowledge of drag racing at the start line the stageing beams are broken by the front tires which turns on the prestage light then the staged light as you roll a bit farther in, Okay so far?
Now the clocks don't start when the light turns green they start when your tire moves forward and the beam is Unbroken, How am I doing? My question is at the finish line do the tires again break the beam stopping the clocks or are the beams higher and the front of the car breaks the beam? I say it's the front bumper because thats when the "Photo Finish Camera trips" but what do I know, most the time I drive a Chevy Dualie that gets beat by 40 year Beatle Bugs at the stoplights
I don't see ND so I guess I get to do the answer.
The clock starts when the top amber turns on. For pro tree, all 3 ambers come on together. On a sportsman tree, they fall 1/2 second apart.
on a pro tree, the green light is 0.400 of a second after the ambers. This is why old time slips show .400 as a perfect light.
on a sportsman tree, this time is 0.500.
So if you leave on the top amber on a pro tree, you're leaving .400 early. On a sportsman tree, you leave 1.5 seconds early. If you leave before the top bulb, you get a "LB3A" which means "Left Before Tree Activated"
I'm not sure exactly what defines reaction time. I want to say it's when all 3 beams (Prestage, Stage, Deepstage) are broken in a sequential order.
At the other end, the timing beacon is located exactly 5 inches above the racing surface per rules, though some tracks may use a 6" height. What trips this beam can depend on the vehicle. A few years ago, Pro Stock Bike has trouble because the tires/spokes would not trip the beams, but the fairings would.
link to article- 2005
On our camaro, the body trips it about midway between the bottom edge and the grille. On dragsters or tall door cars, there is usually a "stripe taker" to break the beam. Roadsters can allow the fenders, tires, or a stripe taker to break the beam. I believe a stripe taker can extend up to 30" ahead of the front spindle (45" in some rule books). As such, this can make a track as short as 1317.5 (1316.75) feet, as the stripe taker will trip the beam 2.5 (3.75) feet before the tires (which initiated the run).
link 1 link 2 link 3 link 4
