Oh man, you guys aren't gonna believe this time slip!

Mike Puckett

SCCoA Member
You know, it's pretty hard to beat someone when he's going 988 MPH at the 1/8th mile mark, that's my story and I'm stickin' to it. Geez, the G forces this guy must have endured! Actually, it was my good buddy Mel and his 402cid '67 Camaro. I believe it was the fastest speed of the day including the 2 jet cars that could only do a measly 288 mph. The right lane just couldn't get a grip on the 1/8th mile speeds on 1/4 mi runs all day and that was the record. But, keep looking further and you'll see what else is phenomenal about this race. We both dialed a 13.50 for a heads up race and we both ran dead-on 13.487's. His .532 light just nipped my .538 and was the difference in mov! What a race even if I did lose. I had the early lead out of the hole but he came on, on the upper end and evened it up. Since we both broke out the only thing I could have done was to let off at the end to keep from breaking out but I had no idea that we were that quick.
 

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Well mike its like they say, a good bit of bracket races are won and lost right at the tree, and that is a classic case right there. Pretty odd glitch with the timing lights too. I'm sure your friend will use it to his advantage with all his buddies though ( I know I would :D )
 
I've won and lost by .006 or less about a dozen times over the last 3-4 years. I'd rather lose by that than get smoked though. My closest victory was by .0002! Now that's close, 200 microseconds. That's getting close to the rise time of the photocells.
 
Sounds like someone needs to fix their code. What brand of photoeyes do they use? 200 micro seconds is really really fast are you sure it's not 2 ms?

Jeff
 
I don't know what types they use but most photocells like the ones I work with react in the low micro to nanosecond range. I suspect that some of the laser sensors used in fiberoptic data transmission lines are in the 1 picosec or better range. 2 ms would be .002 sec. And .0001 sec in distance at the end of the 1/4 mi at 100 mph is the thickness of what? Thin cardboard? I did have one of my colleagues at work question the validity of these close times due to limitations in the electronics. I still can't get over that 988 mph 1/8 mi, lol. When I ran in the right lane I was only doing '21 mph' at the 1/8th even though I ran a 13.538.
 
I can't imagine that they use anything more sophisticated than a PLC. Man I just about wrote the code sitting here earlier today. I looked around at most of the manufacturer catalogs I have here (Banner, Sick, Keyence, AB, few others) most of them are in the 2ms range as far as advertised response times. You must deal with some pretty fast paced stuff over there. I would bet it’s something to do with you guys running so close, something in the code. Did you see any other time slips like that?

Jeff
 
Our brushless DC motors can spin as fast as 9000 rpm with a 512 pulse per revolution optical encoder so they do need exceptionally good resolution for proper motor speed and positioning control. We also use the Keyence PS-T1 for controlling machine function. The data sheet shows a 500 microsecond response time for it which is fine for stopping the machine. 2 ms at the drag strip, though, isn't going to cut it as I see lots of races decided by less than that.
 
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