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OFF THE SLALOM TOPIC: Hobby Park TOP SPEED?

Posted: Thu Nov 16, 2006 4:33 pm
by Wesley Tucker
We REALLY need to SPEED TRAP Hobby Park. I just did some rough calculations and found that Mike Duquette's winning speed was around 41 miles an hour. This is about the same as what 66 posted on Trade Street.

The differerence is that at Trade Street we used the "speed trap" timing method instead of overall downhill time. What's the difference? At Trade Street we set the timing strips 88 feet apart on the "sweet spot" of the hill. This reflected the absolute fastest time on the hill.

At Hobby Park, though, we just time from top to bottom. It's still fast, but what's the maximum velocity? Setting the tape strips as we do means the clock is running while the skater is getting into his tuck, as he accelerates down the hill and most importantly as he SLOWS DOWN after the transition and starts heading UP HILL to the finish line.

I'm not really good at math and geometry, but I wonder if skaters are topping over 50 MPH at Hobby? There's only one way to find out:

Set two strips 88 or 44, 22 or 11 feet apart at the maximum grade on the hill and measure the top speed. (These numbers all just happen to be easy for converting 5280 feet in a mile to 60 seconds in a minute. 88 is 1/60th of a mile, 44 is 120th, etc. You get the feet per second and then easily convert it to miles per hour. Trust me. It works.)

I've said this before and some have commented that it might be dangerous tripping the tape switches at that speed. Fine. Let's get Tom Thompson's infrared system up to North Carolina and use it for timing.

I don't downhill (yet). Why am I interested? Because. The hill is there and I'm really interested to find out how FAST skaters go down on it. Let's find out.

Posted: Thu Nov 16, 2006 5:06 pm
by Mr Surly
I agree, a trap is needed on Hobby Hill. The 88 foot method would be perfect
there. You could even incorporate the equine system within the tape strips. You'd
have an overall time [with no true distance] and then the trap speed. Of course,
that would be good for a test, and probably not a race.

I rode across the tape switch this Summer, and it was a bit hairy hitting it in
a tuck. Though it's not as mind freakingly scary as that gunshot sound you
get when running over the metal plate at the top for the first time.

Posted: Thu Nov 16, 2006 5:52 pm
by Ron Olsen
I see on the trackmate site that the new trackmate timer will do MPH calculations for you and displays it on the screen. They show a video of a RC car going 120 MPH (actual!). The speed trap was about 3 feet apart.

Ron

Posted: Thu Nov 16, 2006 7:00 pm
by Christopher Bara
hey,....what every happened to the race times for the DH....or even the GS....anyway?

Posted: Thu Nov 16, 2006 8:02 pm
by Troy Smart
Yea!
What he said!

Posted: Thu Nov 16, 2006 8:07 pm
by Wesley Tucker
The Downhill results are in a notebook. They are hand written. They need to be transcribed. They will be posted when Marion or D-Holt posts them.

The "B" bracket GS was also done by hand. The followup is identical to the downhill.

The "A" bracket GS was done on the computer. I have no idea what Dan did with the results.

It's been 11 days. Why have they not been posted? Because the work hasn't been done.

Anything else?

Posted: Thu Nov 16, 2006 8:42 pm
by Chris Barrett
its a conspiracy!!! ;)

Posted: Thu Nov 16, 2006 8:54 pm
by Christopher Bara
"Anything Else"?

yep...

Did you get the Email i sent on changing my Avatar?

Posted: Thu Nov 16, 2006 9:22 pm
by Chris Favero
equine would be the way to go.you could set those eyes up to 30ft apart so the racer does not have to hit a certain line on the hill.cf

Posted: Thu Nov 16, 2006 9:29 pm
by Wesley Tucker
Christopher Bara wrote:"Anything Else"?

yep...

Did you get the Email i sent on changing my Avatar?
Yes

Timing trap speeds

Posted: Thu Nov 16, 2006 9:35 pm
by Chris Novatny
Wes,
I was looking at trying to modify the circuit that controls the IR beams of our system (Equine System). They have a 5+ second delay that starts when the first beam is broken, so for the DH @ Hobby Hill the speed trap would have been 1/2 the length of the entire hill (not a good distance for a "trap speed". I'm going to make the delay adjustable.

cnova

Posted: Thu Nov 16, 2006 11:04 pm
by Marion Karr
Sorry for the delay on the results....we will have them up tomorrow..

I have been trying to get my real job back back on track and the DH results are in a notebook that I am picking up tonight.

Thanks for your patience.

Marion

Posted: Thu Nov 16, 2006 11:49 pm
by Christopher Bara
sh*t Marion....that's the good part about throwing the last big race of the year.....we've got all winter........it's nothing urgent

Posted: Fri Nov 17, 2006 12:23 am
by Ron Olsen
And to add to the original topic - John Karg has a speed gun, he used it on me at Red Clay where I was 26mph off the last offset. Not sure how accurate those are, but it's another option.

RonO

Posted: Fri Nov 17, 2006 12:55 am
by Wesley Tucker
Ron,

Radar guns are cool. The only issue with them is consistency and accuracy. With a speed trap every skater experiences the exact same condition for top speed. A speed trap is the same as total elapsed time except the total elapsed time is less. There's still acceleration and deceleration in a speed trap, only less pronounced.

With a radar gun you're looking at pointing and clicking. Pointing farther up the hill or farther down the hill means one skater will be gauged differently than the other.

Of course, it's great for just jamming and seeing everyone's speed, but for competition it's too inconsistent. Unless there is a way to mount the radar gun and have it trip in exactly the same place everytime, then it would work.

Maybe I'm getting ahead of myself. A radar gun would be great just to eyeball top speeds, but ifwe wanted to add another level to downhill competition, we'd have to use a trap.

Posted: Fri Nov 17, 2006 3:56 pm
by Mr Surly
the softball/baseball "pitch guns" are pretty cheap. came close to buying one for
a hobby jam this year. i agree it would be fun for jams and average times.

Posted: Fri Nov 17, 2006 3:58 pm
by Mr Surly
Christopher Bara wrote:sh*t Marion....that's the good part about throwing the last big race of the year.....we've got all winter........it's nothing urgent
sorry Bara, i wrote down the top ten times for the DH race before i
drove home from Hobby Park. i have no idea where i put them now.

the big notebook is still in statesville [as Marion pointed out]