|
|
Post by Murph on Nov 16, 2011 19:15:05 GMT -6
Don't have this figured out yet. Work in progress.  |
|
|
|
Post by RacerX on Nov 17, 2011 12:41:18 GMT -6
Things that make you go: HHmmm!!!
|
|
|
|
Post by Murph on Nov 17, 2011 17:21:27 GMT -6
The center weights are very close to the track. The weights will not touch the center guides of the aluminum track.
The ideology is to keep the weight low and centralized in the middle of the car and not outward towards the sides of the car. The cars are extremely stable.
Remarkably, the cars are stable in the stop section. So far, the performance of this design is equal or slightly less with respect to track times. From a statistical standpoint, I need more run time and data to make any statements with a high degree of confidence.
Onward! Push the envelope!
Murph
SLT
|
|
|
|
Post by cycrunner on Dec 12, 2011 2:01:07 GMT -6
Murph.
Granted that low C.G. is better, but isn't it also better to have the weight position biased toward the side of the car which has the dominant front wheel. The purpose being to load the rear wheels as nearly equal as possible. Equal or near equal loading of the rear wheels makes the resulting friction more the same for each wheel. This has usually been touted as a good thing to do in building cars.
|
|
|
|
Post by Murph on Dec 12, 2011 11:16:56 GMT -6
I agree Cyc. Equalizing weight across the rear wheels is considered "best practice". You know me. I am always going against 'status quo" when it comes to pro racing. I push design to the limit to places you should not be.
However, if you run aggressive COM such as 3/8" in front of rear wheels, there is little mass to move to one side of the rear wheels. When you get into 5/8 to 3/4" COM, you weight distribution comes more into play.
Running aggressive COM leaves you venerable to getting pushed around by the cars next to you if you cannot get out ahead of them. Just ask BSB and 5 K. They beat me up bad when I came back and raced in the Hot Rod Division in the November PWDR Race. That Hot Rod ran 3/8" COM. That Car now runs 5/8" COM.
The picture car is very aggressive. This car has not been optimized yet. I made too many changes at once on this car. It was running different wheels than I normally run.
It also has a crack in the body by the DOM Front Wheel when it came back from racing at PWDR. Guess I made the body too thin at this area! A little epoxy will repair.
Your ideology does not take into effect the torque that comes into play in rail riding. Our pro cars have minimal torque. However, an average BSA Cub Scout Car might have significant torque messing with the rear wheels, especially on rough wooden tracks where you run considerable drift to keep the DOM Front Wheel on the rail.
My fastest limited car "Trophy Wife" does not have equal weight distributed over the rear wheels.
I have actually moved the weight around and found little impact on my aggressive cars.
Thanks for your input! By the way, I have been very impressed by your speed on graphite with respect to your spec-tune car at PWDR. Nice work!
|
|
|
|
Post by cycrunner on Dec 14, 2011 17:09:55 GMT -6
Murph,
I have my two qualified cars running Sat in the PWDR Spec/Tuner. I fine tuned al little to gain a bit of speed but who knows how ZZ and the others will do. Should be some very close times!
I have never quite been able to get equal weight distribution for the rear wheels, so I don't know if actually getting to that goal would make a difference.
|
|
|
|
Post by Murph on Jan 29, 2012 16:00:33 GMT -6
I am currently modifying the weight distribution on these cars. I am still keeping the weight very low in the car. Just moving weight front-ward and towards the side of the dominant front wheel.
I will post new pictures of the weight distribution and results in about a month.
I don't have much base line on the times because I was leveraging different types of wheels on the original testing.
Murph
|
|
