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Old 03-29-2007, 11:39 AM   #2731
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Sounds risky.......one of those falls off.....DQ here ya come....

Weren't these lipos supposed to save ya money?

Later EddieO
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Old 03-29-2007, 11:45 AM   #2732
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So on the surface, I would think having that weight as low as possible would be a good thing since it keeps the CoG low. Is that true, or do you think there's some issue with keeping so much weight down low? I mean, with the tray, a lot of it is actually lower than the top surface of the chassis.
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Old 03-29-2007, 11:49 AM   #2733
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Quote:
Originally Posted by EddieO
Sounds risky.......one of those falls off.....DQ here ya come....

Weren't these lipos supposed to save ya money?

Later EddieO
Yea, no doubt. I think it would be hard for one to fall off, they're pretty much locked into place by having the battery in there. And tungsten is HARD, a loose piece flying around in a car could end in tears.

Currently, the reduced weight of the LiPo packs has turned out to be less beneficial than most people hope, since there's a lot of trouble involved getting weight added back in. The nice thing, though, is that you can only add enough to get your car right to the minimum weight. But yea, this solution was not terribly cheap.

Didn't Andy Moore recently get DQ'd from an A run in that nitro race after the birds for losing a lead weight during the race?
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Old 03-29-2007, 11:56 AM   #2734
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I think that was Groskamp.
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Old 03-29-2007, 12:00 PM   #2735
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Originally Posted by KyLayfield
I think that was Groskamp.
Err, ya, sorry.
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Old 03-29-2007, 12:57 PM   #2736
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Originally Posted by Kropy
Keith ~ Here's your new body for your Type-R, Good luck at FastCasts.
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Old 03-29-2007, 12:58 PM   #2737
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Quote:
Originally Posted by syndr0me
So on the surface, I would think having that weight as low as possible would be a good thing since it keeps the CoG low. Is that true, or do you think there's some issue with keeping so much weight down low? I mean, with the tray, a lot of it is actually lower than the top surface of the chassis.
It will change your roll characteristics as you just shortened your moment arm in effect having the feel of a higher roll center than previously. You would probably need to adjust the roll center a bit to compensate and replicate the feel of a NiMH pack. Thankfully our suspensions are very adjustable so we won't run into a situation of not having any roll at all. It will also change the amount of weight transferred during acceleration and deceleration as well. The amount of weight transfer that occurs is based off of the cg height. Or inertia force x cg height / wheelbase. The same also applies to weight transfer from side to side as well substituting track for wheelbase. Unfortunately I wouldn't even hazard a guess at the amount it changed, although you could do some approximating by calculating the center of gravity of a NIMH and LiPo with weights. Just figure out the balance in the 3 axis. With the NIMH you could just measure it, the LIPO would be a bit harder as you would need to balance it on end which is the important one for our purpose as that would represent the vertical change. If that difference is very small I wouldn't sweat the bigger picture then. And of course as a general rule minimizing weight transfer is a good thing as it allows you to utilize the grip of all the tires to the maximum especially since we are dealing with an AWD machine.

Now if Losi would just release the CAD data would could figure out the CG change without having to do a painful amount of math and balancing of cars.

Mike Slaughter To the math cave!
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Old 03-29-2007, 01:12 PM   #2738
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Quote:
Originally Posted by masterhit
It will change your roll characteristics as you just shortened your moment arm in effect having the feel of a higher roll center than previously. You would probably need to adjust the roll center a bit to compensate and replicate the feel of a NiMH pack. Thankfully our suspensions are very adjustable so we won't run into a situation of not having any roll at all. It will also change the amount of weight transferred during acceleration and deceleration as well. The amount of weight transfer that occurs is based off of the cg height. Or inertia force x cg height / wheelbase. The same also applies to weight transfer from side to side as well substituting track for wheelbase. Unfortunately I wouldn't even hazard a guess at the amount it changed, although you could do some approximating by calculating the center of gravity of a NIMH and LiPo with weights. Just figure out the balance in the 3 axis. With the NIMH you could just measure it, the LIPO would be a bit harder as you would need to balance it on end which is the important one for our purpose as that would represent the vertical change. If that difference is very small I wouldn't sweat the bigger picture then. And of course as a general rule minimizing weight transfer is a good thing as it allows you to utilize the grip of all the tires to the maximum especially since we are dealing with an AWD machine.

Now if Losi would just release the CAD data would could figure out the CG change without having to do a painful amount of math and balancing of cars.

Mike Slaughter To the math cave!
Wow, that's a lot to digest. Thanks for the detailed information, I guess I've got a lot of experimentation ahead of me.
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Old 03-29-2007, 01:15 PM   #2739
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Quote:
Originally Posted by masterhit
It will change your roll characteristics as you just shortened your moment arm in effect having the feel of a higher roll center than previously. You would probably need to adjust the roll center a bit to compensate and replicate the feel of a NiMH pack. Thankfully our suspensions are very adjustable so we won't run into a situation of not having any roll at all. It will also change the amount of weight transferred during acceleration and deceleration as well. The amount of weight transfer that occurs is based off of the cg height. Or inertia force x cg height / wheelbase. The same also applies to weight transfer from side to side as well substituting track for wheelbase. Unfortunately I wouldn't even hazard a guess at the amount it changed, although you could do some approximating by calculating the center of gravity of a NIMH and LiPo with weights. Just figure out the balance in the 3 axis. With the NIMH you could just measure it, the LIPO would be a bit harder as you would need to balance it on end which is the important one for our purpose as that would represent the vertical change. If that difference is very small I wouldn't sweat the bigger picture then. And of course as a general rule minimizing weight transfer is a good thing as it allows you to utilize the grip of all the tires to the maximum especially since we are dealing with an AWD machine.

Now if Losi would just release the CAD data would could figure out the CG change without having to do a painful amount of math and balancing of cars.

Mike Slaughter To the math cave!

'WOW'
Now my head hurts
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Old 03-29-2007, 01:32 PM   #2740
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Quote:
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'WOW'
Now my head hurts
damn x2
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Old 03-29-2007, 01:42 PM   #2741
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That guy has way too much time on his hands to be thinking of stuff like that!!
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Old 03-29-2007, 01:42 PM   #2742
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Malc, you get your car yet?
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Old 03-29-2007, 01:54 PM   #2743
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Quote:
Originally Posted by TheCoolCanFanMan

'WOW'
Now my head hurts
You think that's bad, get him started on how costly foam tires are, but rubber tyres, though having less grip overall, are more pleasing to the overall racing experience. He could probably fill up a whole page on his own.... To which I can only nod my head and respond with a "Yeah, I know."

Bill D. (who is not the guy in the wheelchair in Mike's avatar, but probably related.)
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Old 03-29-2007, 01:57 PM   #2744
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It sure seems like people are getting tired of foams lately.
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Old 03-29-2007, 01:58 PM   #2745
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Well, since this years carpet racing is winding down, the few people who were able to run the car did very amazing with it in my opinion. It is nice to finally say the car is on the market instead of hearing from racers, when will it be available. Anyways, I must say this car will be another competing fro the win in the next carpet season.

I am really looking forward to running this car on carpet and asphault with rubber tires.

I would also like to take this chance to welcome our latest drivers to the team, Dominic Favorito, Jason Schreffler, Larry Fairtrace, Rob Love and Chris Mockerman. Welcome racers and have fun...
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