Hey TXCHEMIST What percentage can you derive out of this?

T

The Iceman

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Feb 23, 2014
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Bracket Racer did a lot of testing with Steer and speed differences, Can you calculate what percentage the steering has in the his speed runs for his car? So what I'm looking for (for example) Steering is only 12% of the speed factor of the car. Please and thanks!

Note: I'm guessing run # 2 and 10 are bad staging??

Steer- 6 in 48- 2.7055 std dev- .0013

5.5 in 48- 2.7024 std dev- .0004

5 in 48- 2.7004 std dev- .0009

4.5 in 48- 2.6994 std dev- .0015

4 in 48- 2.6987 std dev- .0010

3.5 in 48- 2.6988 std dev- .0013

3 in 48- 2.6970 std dev- .0011

2.5 in 48- 2.6961 std dev- .0012

2 in 48- 2.6955 std dev- .0011

1.5 in 48- 2.6967 std dev- .0004
1 in 48- 2.7028 std dev- .0019

.5 in 48- 2.7099 std dev- .0039

http://www.pinewoodderbyonline.com/post/how-much-does-over-steering-cost-6404272?highlight=steer+numbers&pid=1280381592#post1280381592
 
Iceman, I would have said that #'s 2 and 10 were good staging! lol!

I only added the deviation numbers to illustrate how stable the car was for each group of runs. If you look at the steer at .5 in 48" you can see that it was the least stable since the deviation was more than twice what it was in any other group.
 
fat finger test
blah

 
It is super hard to isolate the importance of each variable. It is a little easier to look at a test like this and draw lots of useful conclusions to help optimize this variable and then go optimize something else. If you didn't get your drift correct, you will have a problem figuring out if the last bore prep helped. If you have a bit of tow out on the back axles, it can slow you but the drift amount might still be the same ( unless tow out on just one wheel!)
. You can't tell from just this test what all the other variables might be doing.
Best to keep a notebook and write up as you go. This is nice data and should be instructive to all.
BRtest.jpg

 
Correct Kinser, and actual time is not the most important clue, it is to find where a particular car starts to lose speed from too much tune and to see that it can be made even better with an edge treatment. If you get to tune on the actual track, of course you can crank it to optimum. But the general curve is what every car should follow. slow and variable with no drift, fast improvement as drift added, mild slow up and then more pronounced slow up as more drift added. Now builder to builder gets even wilder because of what weight is on the front DFW can change this curve a bit. Super light DFW can take a lot more drift and not slow down, and might need a lot of drift. A heavier front end might drop off fast, so just a bit of drift is good..
 
bracketracer said:
Iceman, I would have said that #'s 2 and 10 were good staging! lol!

I only added the deviation numbers to illustrate how stable the car was for each group of runs. If you look at the steer at .5 in 48" you can see that it was the least stable since the deviation was more than twice what it was in any other group.
Click to expand...

Sorry Bud, I guess I don't understand where the Dev are derived from. (thought I did! /images/boards/smilies/smile.gif)

txchemist said:
BRtest.jpg
Click to expand...

Thanks TXCHEMIST your graphs always help put things in perspective!!!

Kinser Racing said:
That table wouldn't stand true for my cars. Every builder is going to be different.
Click to expand...
so true, but I would guess that each class would have it own simular ark. (and each person within)

So does this sound right? So the percentage of speed that the steer controls for this car is only??

Let me Try.

Max is 2.79055
min = 2.6955
diff= 0.01956

so diff/min = 0.00725 or .725 %
Steer only controls .725 % of the speed roughly for this car, am I thinking right????
 
The Iceman said:
So does this sound right? So the percentage of speed that the steer controls for this car is only??

Let me Try.

Max is 2.79055
min = 2.6955
diff= 0.01956

so diff/min = 0.00725 or .725 %
Steer only controls .725 % of the speed roughly for this car, am I thinking right????
Click to expand...

I don't see 2.79055 as a data point Ice. I think you meant 2.7099 maybe?
So .534%
 
Here we go with all this math stuff again.
hmmm
remember, baby steps, I just learned to read last year.
 
bracketracer said:
The Iceman said:
So does this sound right? So the percentage of speed that the steer controls for this car is only??

Let me Try.

Max is 2.79055
min = 2.6955
diff= 0.01956

so diff/min = 0.00725 or .725 %
Steer only controls .725 % of the speed roughly for this car, am I thinking right????
Click to expand...

I don't see 2.79055 as a data point Ice. I think you meant 2.7099 maybe?
So .534%
Click to expand...

Yep sorry was in a hurry for a Cubscout go see it! Thanks!
 
txchemist said:
Correct Kinser, and actual time is not the most important clue, it is to find where a particular car starts to lose speed from too much tune and to see that it can be made even better with an edge treatment. If you get to tune on the actual track, of course you can crank it to optimum. But the general curve is what every car should follow. slow and variable with no drift, fast improvement as drift added, mild slow up and then more pronounced slow up as more drift added. Now builder to builder gets even wilder because of what weight is on the front DFW can change this curve a bit. Super light DFW can take a lot more drift and not slow down, and might need a lot of drift. A heavier front end might drop off fast, so just a bit of drift is good..
Click to expand...

Well Said TX
 
I thought this alternative graphic representation might help;


Looking at the thread with the source data, I'd say that some things to be aware of is that the sigma's are based on 4 runs per setting (probably not enough to draw a good conclusion), and it was run on a wood track.
 
ChrisF said:
Looking at the thread with the source data, I'd say that some things to be aware of is that the sigma's are based on 4 runs per setting (probably not enough to draw a good conclusion), and it was run on a wood track.
Click to expand...

Yes, it was a small sample group, but you could run that particular car 20 times per setting and it would still repeat the same numbers. The standard deviation would be less with a larger sample group though.
 
The Sigma's. Dang there was some hot chicks in that sorority.
smile
Click to expand...

...that reminds me...back in the day there was this sorority called Phi Sigma Rho...we used to call them Five P....oops never mind...wrong forum.

bracketracer, when I can find some time, I'll use the deviation displayed by your sample and derive an "n" for a good confidence interval (95% probably)...no promises though because it would involve unlocking parts of my brain long in disuse. Might need some "truth serum" as my friends call it.
 
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