R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 05-27-2008, 06:01 PM   #16
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

I really don't see why capacity should be lower for stock. If a pack is limited by the ROAR size that will pretty much stop the increase in capacity.

The price of Lipos doesn't only have to do with the capacity of the pack. The C rate has an impact on price and so does the quality of the materials used to make the cells/packs.

SMC will be releasing a 3200/28C pack and there is no way we can sell it at the price of the Orion 3200 as our packs are more expensive to make.
Danny/SMC is offline   Reply With Quote
Old 05-27-2008, 06:15 PM   #17
Tech Fanatic
 
trailranger's Avatar
 
Join Date: Feb 2007
Location: Springfield, MO
Posts: 946
Default

I perfer reducing the total vehical weights for classes that use LiPO.

Mason has a point, at what point does the extra weight/capacity slow the car down.
trailranger is offline   Reply With Quote
Old 05-27-2008, 06:18 PM   #18
Tech Lord
 
syndr0me's Avatar
 
Join Date: Dec 2004
Location: 5280 Raceway
Posts: 13,140
Trader Rating: 32 (100%+)
Default

So I'd have to buy one pack for racing, and another for extended practice sessions? Screw that.
syndr0me is offline   Reply With Quote
Old 05-27-2008, 06:24 PM   #19
Tech Champion
 
Join Date: Nov 2001
Location: Hawaii, USA
Posts: 7,186
Default

Quote:
Originally Posted by trilerian View Post
We just go lipo packs legalized for racing, and already people are complaining. And I am going to post something here that people may disagree with, but I think it to be true:

Budget minded racers are not going to win. And it is not even about the money, it is about the mindset. You know "that guy" at your track who can whip anyone with anyones car. He is not budget minded, he does not set limits, his expectations are never met, he will never be satisfied no matter how bad he beats the competition. It is a complete mind set, he will do whatever it takes to be "that guy". Unfortunately that guy cannot be constrained by anything. What I am trying to say, is that if you set limits on anything, you will be constrained by them, they will bleed over to other things as well, and you will always be beat by "that guy".
This is so true! The only thing I would add to that is it is the budget minded racers who are also very competitive people. Until recent years I was always a budget minded racer because I didn't make enough money to afford a lot of stuff the top racers did. But my goal was not to win races but to better myself as a driver, to work my way up to the next higher main with the equipment I had. Eventually I worked my way up to the A mains locally and even won a few races here and there.
InspGadgt is offline   Reply With Quote
Old 05-28-2008, 12:34 AM   #20
Tech Fanatic
 
Join Date: Jun 2007
Posts: 947
Trader Rating: 1 (100%+)
Default

Ya know this is kind of interesting. I don't remember anything about a capacity limit for NiMH.

Is it possible the author of the first post here got whipped by a hardcased lipo equipped car and decided to complain about it, instead of adapting?

Quote:
If ROAR says it limiting capacity by limiting the volume, then why a 58% volume increase over NiMH?
It's simply a case of how the cells are constructed. Lipos are prismatic, NiMH cells are cylindrical. Design a cell that is more area efficient (in this case a rectangle) then capacity increases.

Handicapping a new technology just so old tech can compete is not only unfair but counterproductive.

Racing is meant to push technology, not hold it back.
Sabin is offline   Reply With Quote
Old 05-28-2008, 05:26 AM   #21
Tech Master
 
Join Date: Nov 2003
Posts: 1,052
Trader Rating: 16 (94%+)
Default

Quote:
Originally Posted by crazyjr View Post
The only advantage of a bigger lipo, is more run time.
Not True. More Capacity = Higher Average Voltage. Higher Average Voltage = More Power/Speed over the entire race.
kn7671 is offline   Reply With Quote
Old 05-28-2008, 02:18 PM   #22
Tech Fanatic
 
trailranger's Avatar
 
Join Date: Feb 2007
Location: Springfield, MO
Posts: 946
Default

Quote:
Originally Posted by Sabin View Post

Handicapping a new technology just so old tech can compete is not only unfair but counterproductive.
I'm not handicapping a new technology, I would much perfer that NiMH be excluded from racing in Sedan and Off-Road so that the technology does advance in LiPO. Once NiMH are excluded, then the min weight can be lowered.

The reason I am sticking to my guns on the 23mm max height is:
1: it slightly reduces the volume of the cells.
2: Most Buggys and Trucks were desinged with a 23mm tall battery box.
3: Most sedans can accomendate a 23mm tall lipo.
trailranger is offline   Reply With Quote
Old 05-28-2008, 03:37 PM   #23
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by trailranger View Post
I'm not handicapping a new technology, I would much perfer that NiMH be excluded from racing in Sedan and Off-Road so that the technology does advance in LiPO. Once NiMH are excluded, then the min weight can be lowered.

The reason I am sticking to my guns on the 23mm max height is:
1: it slightly reduces the volume of the cells.
2: Most Buggys and Trucks were desinged with a 23mm tall battery box.
3: Most sedans can accomendate a 23mm tall lipo.

Sub-c cells use to be smaller in diameter and length so the sub-c manufacturers eventually decided to push the size to the limit which meant car manufacturers had to update there cars for the bigger sub-c cells to fit.

Now that Lipos are becoming the standard I'm sure car manufacturers will come out with new kits that will fit the maximum Lipo size.

For offroad cars the maximum height , length and width that ROAR has set will fit with no modifications.

Since Sedan car manufacturers like to come out with a new car every year I'm sure they will incorporate the proper changes to there next model.

As with any new technology there needs to be an adaptation stage.
Danny/SMC is offline   Reply With Quote
Old 05-28-2008, 09:23 PM   #24
Tech Addict
 
crazyjr's Avatar
 
Join Date: Jul 2005
Location: middle georgia
Posts: 613
Default

Quote:
Originally Posted by kn7671 View Post
Not True. More Capacity = Higher Average Voltage. Higher Average Voltage = More Power/Speed over the entire race.
I was refering to the question involving stock classes. I use high capacity lipo's for all my rc's, MT's to mambafied stadium trucks, because i want the best use of the c-rating and capacity. But the Question was for the stock classes, where the only real advantage is the added run time. If the Orion 3200/3600's can handle the load in stock, then there is no need for added amp load. You are right though and i should have said it, but thought it was irevelant
crazyjr is offline   Reply With Quote
Old 05-28-2008, 09:34 PM   #25
Tech Addict
 
crazyjr's Avatar
 
Join Date: Jul 2005
Location: middle georgia
Posts: 613
Default

Quote:
Originally Posted by trailranger View Post
I'm not handicapping a new technology, I would much perfer that NiMH be excluded from racing in Sedan and Off-Road so that the technology does advance in LiPO. Once NiMH are excluded, then the min weight can be lowered.

The reason I am sticking to my guns on the 23mm max height is:
1: it slightly reduces the volume of the cells.
2: Most Buggys and Trucks were desinged with a 23mm tall battery box.
3: Most sedans can accomendate a 23mm tall lipo.
Why does the minimum weight need to be reduced? Things are perfect right now. If you reduce the weight anymore, you lose traction and handling. I'm not saying that future cars need to run with the same weight, I'm just saying we need more engineering to accomodate the changes. My T4 is running 1.5 oz more in the rear to seat the truck better in the turns. this is mandatory in every truck and buggy (T4/B4) but a blacktop runner to keep it on the track. Right now my rc's will pass weight tech (not done) with a 3700 flightpower soft pack, I prefer the 8000mah maxamps in my T4 and the 3700 to 5000mah in my buggies (B4 and SBV2pro) and they run great and over the minimum.

One problem with the minimum rule, the maxamps 5000 2s lipo is in fact under the 23mm height. i have not measured it myself, but if the NIMH is at 23mm, then the 5000 is in fact shorter, because i got to have a piece of foam to hold the pack down in either my T4 or B4
crazyjr is offline   Reply With Quote
Old 05-29-2008, 09:25 AM   #26
Tech Fanatic
 
trailranger's Avatar
 
Join Date: Feb 2007
Location: Springfield, MO
Posts: 946
Default

The thing with reducing the weight for the classes is a cause/effect from going to LiPO. My Reedy 5000 weighs about 290g, my EnerG 4600's weight 435! A 145g difference. Orion 3200's weigh 200g, 235g lighter than NiMH.

To encourage LiPO use accross the board in the 7.2V/7.4Vclasses the min weight should be lowered 100 to 250g. Perferably 250g for stock classes and 150g for Modified.

The lower weight limit would discourage larger capacity packs in stock classes. The total min weight can be reduced slightly more than the weight savings of the LiPO's due to reduction in servo needed to steer a lighter car.

The lower weight limit in modified is needed since there would be no benifit to keeping the higher min weight. Tire and drivetrain wear would be reduced as a result to the lower weight.
trailranger is offline   Reply With Quote
Old 05-29-2008, 09:44 AM   #27
Tech Fanatic
 
trailranger's Avatar
 
Join Date: Feb 2007
Location: Springfield, MO
Posts: 946
Default

In response to the the higher weight is needed for handling and traction.

Rubber does not have a proportional coefficient of friction to the of the forces pushing tire to the track. It is possible for rubber tires to have a negative coefficient and maintain traction when the forces keeping the tire to the track have approached zero. Much like tape sticks to walls, rubber can have tractive forces as long as there is contact.

The opposite is said for rubber when excess forces are applied or in the case of excess weight pushing the tire to the track. In the event that more force is applied to maintain the contact between the tire and track, the coefficient of frictions begins to reduce and eventually resluts in less net traction.
trailranger is offline   Reply With Quote
Old 06-06-2008, 12:24 AM   #28
Tech Fanatic
 
Join Date: Jun 2007
Posts: 947
Trader Rating: 1 (100%+)
Default

Quote:
Originally Posted by crazyjr View Post
Why does the minimum weight need to be reduced? Things are perfect right now. If you reduce the weight anymore, you lose traction and handling.
If that were true, Mustangs would out-handle formula fords.

There's something called rolling resistance with pretty much any tire. you reduce the weight, you reduce rolling resistance. Reduce the resistance, reduce the wear. When you reduce the wear, you get the option to run an even softer and grippier tire. Ergo, traction and handling INCREASE.

But there comes a point where you nail a chassis' minimum weight, which is pretty much the ideal limit. Anything below that will lead to strange handling.

Last edited by Sabin; 06-06-2008 at 01:48 AM.
Sabin is offline   Reply With Quote
Old 06-06-2008, 10:31 PM   #29
Tech Regular
 
decibels's Avatar
 
Join Date: Apr 2008
Location: in a house
Posts: 431
Trader Rating: 3 (100%+)
Default

Quote:
Originally Posted by Sabin View Post
If that were true, Mustangs would out-handle formula fords.

There's something called rolling resistance with pretty much any tire. you reduce the weight, you reduce rolling resistance. Reduce the resistance, reduce the wear. When you reduce the wear, you get the option to run an even softer and grippier tire. Ergo, traction and handling INCREASE.

But there comes a point where you nail a chassis' minimum weight, which is pretty much the ideal limit. Anything below that will lead to strange handling.
Well i agree my bro races 5 cell i race stock ( 6 cells )his car is always more reactive enabling him to run softer setups to add more grip and still having better reactivity!! but there is another thing you load the tires with g force when accelerating and decelerating and when cornering so you still have enough weight pushing on the tires! but yes if your car was a paper weight it would probably lift off the track!! lol but thats also what your body is for!! so you can also run a body that is higher in downforce whilst still creating the same drag!!! thats my thoughts!! but im no scientist!! lol
__________________
Team Wave Speedies
Thunder power lipo's
flying fox rc
!!And an idiot with a controller!!
decibels is offline   Reply With Quote
Old 06-07-2008, 01:32 AM   #30
Tech Fanatic
 
Join Date: Jun 2007
Posts: 947
Trader Rating: 1 (100%+)
Default

yea exactly. a lighter car allows for a softer suspension and stickier tires.. not only that, but the rubber will last longer.

add a little negative camber to boot and it bites into the corner like someone stuck a giant magnet underneath.
Sabin is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
ROAR 10 Turn Limit / FOAM tire Rule Passed for Sedan SirSpeedy Electric On-Road 74 09-29-2009 01:18 PM
ROAR Rules: Should there be a $$ limit on batteries for approval? or8ital Electric On-Road 22 09-11-2008 01:00 PM
Lipo - odd lipo capacity usage situation padailey Electric On-Road 7 05-28-2008 11:45 AM
Lipo voltage limit? Francis M. Electric On-Road 30 04-04-2008 04:55 PM
Stock vs Mod. classes question macnkitty2002 Electric On-Road 13 03-14-2005 10:01 AM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 02:26 PM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net