R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 07-11-2006, 10:48 PM   #151
Tech Champion
 
AdrianM's Avatar
 
Join Date: Aug 2001
Location: Tampa, FL
Posts: 5,914
Trader Rating: 4 (100%+)
Default

Quote:
Originally Posted by bvoltz
I thought the Worlds had a really high air temp, thus causing some problems then the tire rule make it fun for others..

The only reason to go to 4 cells is to kill advancement, LIPO.....
I use a lot of LiPo batts in my r/c planes so dont get me wrong I like the cells...but...just because LiPo's are superior energy storage technology in general dosen't mean they are superior for our application.
__________________
Adrian Martinez
What I run: Schumacher Mi5/Associated RC10R5.1/Associated RC12R5.2/Futaba/HobbyWing/Team EA Motorsports/BSR Racing
Where I run: Florida Indoor R/C Complex/Thunder Racing/Florida On Road State Series
AdrianM is offline   Reply With Quote
Old 07-11-2006, 10:51 PM   #152
Tech Champion
 
AdrianM's Avatar
 
Join Date: Aug 2001
Location: Tampa, FL
Posts: 5,914
Trader Rating: 4 (100%+)
Default

Quote:
Originally Posted by Chris Adams
If we went to five cells, wouldn't this effectively do what moving from 7 to 6 did? Possibly make the cars easier to drive, motors last longer, and we would still have the runtime that a basher/ newbie finds to be the 2nd most important piece of rc behind speed...
Yes.

The 2wd off road guys are already running 5 cells under certain conditions and going faster.

The Oval guys are going just as fast or faster now with 4 cell than they did with 6 cell.
__________________
Adrian Martinez
What I run: Schumacher Mi5/Associated RC10R5.1/Associated RC12R5.2/Futaba/HobbyWing/Team EA Motorsports/BSR Racing
Where I run: Florida Indoor R/C Complex/Thunder Racing/Florida On Road State Series
AdrianM is offline   Reply With Quote
Old 07-11-2006, 10:53 PM   #153
Tech Fanatic
 
Join Date: Jan 2003
Location: Pasadena Ca. U.S.A
Posts: 771
Default

all I am saying is that when we went from 6 to 4 cell in 1/12th we also dropped from 12 and 13 turns to 8,9, and 10 turns to get the speed back and also the cars were lighter this way so the speeds were back up....if we go to 4 cell in TC what are we going to run 4 and five turns?Who knows but I still think we are going to have all the same problems we have right now.....limit the MAH and the speeds will drop I gaurantee it.....atleast the people that want to make time and win races...
Barry Baker is offline   Reply With Quote
Old 07-11-2006, 10:57 PM   #154
Tech Master
 
Chris Adams's Avatar
 
Join Date: Jan 2006
Location: Dallas,Texas
Posts: 1,003
Default

Shouldn't this be the answer to the whole deal? Obviously, batteries and motors will continue to get better... they new this when they moved from 6 to 7 cells. I see this as the only step that Ifmar could take as it should help alleviate speeds, cost, and drive ability. Any other route other than the current limiter seems to change what all of us have grown to love.
__________________
TEXASEOS.net, RcAmerica, Xray, Hudy, Protoform, Orca, Avid, 2mm Designs, Ulti Tires America

Texas EOS 2018!
Chris Adams is offline   Reply With Quote
Old 07-11-2006, 10:58 PM   #155
Tech Fanatic
 
Join Date: Jan 2003
Location: Pasadena Ca. U.S.A
Posts: 771
Default

Quote:
Originally Posted by Chris Adams
Shouldn't this be the answer to the whole deal? Obviously, batteries and motors will continue to get better... they new this when they moved from 6 to 7 cells. I see this as the only step that Ifmar could take as it should help alleviate speeds, cost, and drive ability. Any other route other than the current limiter seems to change what all of us have grown to love.
You've got a point!
Barry Baker is offline   Reply With Quote
Old 07-11-2006, 11:18 PM   #156
Tech Master
 
Join Date: Oct 2001
Location: Kansas
Posts: 1,596
Send a message via Yahoo to Doug Gaut
Default

Speed is all relative.

Last edited by Doug Gaut; 07-12-2006 at 06:46 AM.
Doug Gaut is offline   Reply With Quote
Old 07-11-2006, 11:23 PM   #157
Tech Champion
 
AdrianM's Avatar
 
Join Date: Aug 2001
Location: Tampa, FL
Posts: 5,914
Trader Rating: 4 (100%+)
Default

Quote:
Originally Posted by Barry Baker
all I am saying is that when we went from 6 to 4 cell in 1/12th we also dropped from 12 and 13 turns to 8,9, and 10 turns to get the speed back and also the cars were lighter this way so the speeds were back up....if we go to 4 cell in TC what are we going to run 4 and five turns?Who knows but I still think we are going to have all the same problems we have right now.....limit the MAH and the speeds will drop I gaurantee it.....atleast the people that want to make time and win races...
Are you roasting motors in 1/12th...nope.

Will 4 or 5 cell stop the roasting of motors in sedans...yup.

Why...because the heat in the motors comes from wattage losses not turned into rotational energy. If you lower the input voltage the overall wattage output will be lower and the heat in the motor/speedo will be lower.

Here's what I mean:

Volts x Amps = Watts output

Lets say our cells can put out 150A for a split sec when shorted.

7.2v x 150A = 1080W Terminal wattage output

4.8v x 150A = 720w Terminal wattage output


Lets use some more realistic numbers

The average mod sedan draws 40-50A during a run. Lets say you get a 4 cell mod sedan to draw the same amps.

7.2 x 45 = 324W

4.8 x 45 = 216W

The 4 cell system will run 33% cooler than the 6 cell system.

The nay sayers will think the cars will be 33% slower but this is not the case. The cooler motor can run more timing and a bigger gear ratio. It will have to to get up to 45A draw. The tops speeds of the cars will be almost identical. The oval crowd has proved this. What you will lose is some acceleration.

We can afford to give that up since on asphalt 19T and Mod motors have the power to light up the tires coming out of corners if you pull the trigger too hard. At the Worlds BL driver were running 30% expo in their radios to keep from lighting up the tires on corner exit.

I dont see a lot negative results from a reduction in cell count.
__________________
Adrian Martinez
What I run: Schumacher Mi5/Associated RC10R5.1/Associated RC12R5.2/Futaba/HobbyWing/Team EA Motorsports/BSR Racing
Where I run: Florida Indoor R/C Complex/Thunder Racing/Florida On Road State Series
AdrianM is offline   Reply With Quote
Old 07-11-2006, 11:41 PM   #158
Tech Elite
 
POOKYT's Avatar
 
Join Date: Oct 2002
Location: Cabot, AR
Posts: 3,584
Default

Going from 7 cells to 6 cells in offroad was a great thing as was going to 4 cell oval racing. I just can't see why it wouldn't work overall for the better in TC racing. I'm with Adrian.

Brant
__________________
EA Motorsports--B-Main Motorsports--Blizzard Concepts--Loose Nuts Racing--BigDog Graphics

My Carbon Footprint is Larger than Yours! :p
POOKYT is offline   Reply With Quote
Old 07-11-2006, 11:47 PM   #159
Tech Champion
 
AdrianM's Avatar
 
Join Date: Aug 2001
Location: Tampa, FL
Posts: 5,914
Trader Rating: 4 (100%+)
Default

Some have said that going to fewer cells will require a huge and expensive change in our current sedans...not true!

The current trend in sedan chassis layout is 6 cells down one side and everything else down the other side. The batteries are heavier than the electronics by ~100g.

Right side:

6 cells 390g

Left side:

Servo 60g
RX 15g
ESC w/fan 30g
Motor 176
Total: 281g

All sedan manufactuers balance thier cars by tucking in the batteries as close to the center as possible. This works great and most sedans on the market today balance perfectly side to side.

4 cells are 260G

To balance a sedan with 4 cells all you have to do is move the batteries out a few mm from where they are now...thats it! A new lower chassis and you are back to a balanced car...and its 130g lighter (just over 1/4 pound)!

If you dont want to buy a new chassis move the RX or ESC over to the batt side and you are balanced.

Like Reto said a lot of testing needs to be done to do before any decisions are made but all in all this does not look like a bad idea at all.
__________________
Adrian Martinez
What I run: Schumacher Mi5/Associated RC10R5.1/Associated RC12R5.2/Futaba/HobbyWing/Team EA Motorsports/BSR Racing
Where I run: Florida Indoor R/C Complex/Thunder Racing/Florida On Road State Series

Last edited by AdrianM; 07-12-2006 at 12:41 AM.
AdrianM is offline   Reply With Quote
Old 07-11-2006, 11:50 PM   #160
Tech Adept
 
Join Date: Apr 2005
Location: Amsterdam
Posts: 105
Default

Okay, why don't we stop talking and start trying 4 or 5 cells.

If we are such experts on this issue it shouldn't be a problem to spend a day trying 4 and 5 cell configurations at the track.

I guess it would make more sense discussing this topic if we have really tried it.

Especially the sponsored top drivers, they have lots of equipments to test the cell limitation.

And while you're at it, give 6 or 7 minute racing a try as well. This way you won't go for 5 turn motors.
MBreve is offline   Reply With Quote
Old 07-12-2006, 12:07 AM   #161
Tech Fanatic
 
ttso's Avatar
 
Join Date: May 2004
Posts: 900
Trader Rating: 1 (100%+)
Default

People in JP already doing 4cells. HK going to have first 4cells race this weekend (and I will be there, if typhoon doesn't ruin my travel plan). I've video of 4cells with 6T motor run at the same pace with 6cells modify, and still everything last longer, and no smoke.

Moding current 6cells belt to 4cells is easy.

1. First you use the forward 4slots for 4cells
2. Remove all leads for weight balance.
3. Move RX to battery side, and put a small RX-battery pack (LiPo would be nice) on the same spot.

In most condition, that's it. If your weight still off to motor/elec side, that usually means 2 things: 1. you are not using 4200/4300 batt; 2. you are using very heavy ESC (ex: brushless).

Either way, the only thing you need is move either ESC or RX+RXbatt to battery side, that's it. You might need to add a few lead to balance it but the left-right weight won't be off many, just check AdrianM's number and you will see.

For those seeing is believing people, I attached 2 photos, FK04 is my testbed, and SDLCG is my friend's. They both close to 50-50 weight balance with 4200 batt (FK04 need a bit more lead on elec side).
Attached Thumbnails
IFMAR AGM in Collegno - Future of ISTC-jimmy-4cells-sdlcg.jpg   IFMAR AGM in Collegno - Future of ISTC-tt-4cells-fk04.jpg  
ttso is offline   Reply With Quote
Old 07-12-2006, 01:08 AM   #162
Tech Master
 
DerekB's Avatar
 
Join Date: Nov 2001
Location: Southern California
Posts: 1,421
Default

Quote:
Originally Posted by AdrianM

Like Reto said a lot of testing needs to be done to do before any decisions are made but all in all this does not look like a bad idea at all.
Here's the thing that should make people stop. You can NOT make a rule change on theory. Test it and prove it, then make the change.

The motive behind this is also the LIPO cell technology. I have heard more than one battery company say they don't want LIPO because they are too dangerous, but that isn't really true. Let's think beyond the next two years and look to the next generation battery.
__________________
Velocity RC Magazine
www.vrcmag.com
DerekB is offline   Reply With Quote
Old 07-12-2006, 01:37 AM   #163
Tech Fanatic
 
Join Date: Aug 2004
Location: UK
Posts: 902
Trader Rating: 3 (100%+)
Default

Quote:
Originally Posted by tonyv
Not my point at all. What we should be looking at is how to prevent that from happening. Someone posted the question whether there is a problem now. I think the answer is not yet given the speed with which races get filled up. But if there are signs that this may change in the future for whatever reason, shouldn't we discuss this now rather than wait until it hits? The type of changes being proposed by Rick take multiple years to implement. Even changing the number of cells will take one or two years to really get of the ground. If we wait until the number of drivers starts to drop significantly won't it be too late to do anything about it?
Tony, sorry I was only joking about stopping Mod TC! So as you say maybe it's not a problem right now but could be in the future, it's good to try and look ahead but things could change. As has been said if Sub C batteries don't advance too much more then there may not even be a problem anyway, and nobody knows what will happen with LiPo and next generation battery technology.

Quote:
Originally Posted by tonyv
That's why the top team drivers switched. My question was why did the other drivers switch in the first place? If everybody had continued running PRO 10 then that would have still been the class that the team drivers run in. The point is that they didn't which killed a great class that was significantly cheaper to run than touring cars.
Don't we all do what the top team drivers do, and race what they race? I agree with you it did kill off a great class that was significantly cheaper to run than touring cars.

Quote:
Originally Posted by EAMotorsports
How about an inline current limiter that is installed on the car for big races? Its been brought up in ROAR I can tell you that for sure. Have 3 limiters. Stock, 19 turn or intermediate and Mod. Hand them out at the big races and take them up the end of the day then hand them out again the next day....everyone gets a different one just for arguments sake. This would take MOST of the battery AND motor stuff out of it.

EA
Eric I agree, good idea. It's been discussed here in the UK before but seemed to flounder due to problems like - what company would make them and could be trusted to make them all exactly the same? - even if everyone gets a different one (just for arguments sake) what's to stop cheating? (swapping them around etc) - current limiters, a technical possibility but it would need rock solid electronics with trusted and foolproof implementation.

Slowing the cars down has been talked about on the forums and elsewhere in the UK. Over here people have been trying out various options regarding cells and motors so it's not all theory by any means, some practical evaluation has been and is taking place. Through on-track testing answers may come up based on reality rather than simply from peoples ideas.

In the end it's like Chris says "Any other route other than the current limiter seems to change what all of us have grown to love."
Terry_S is offline   Reply With Quote
Old 07-12-2006, 01:45 AM   #164
Tech Apprentice
 
Join Date: Jul 2004
Location: Geneva
Posts: 66
Default

I quickly read all comments, but can not really quit understand them. Like Rick mentioned, I did write a letter to IFMAR to spread my concerns. Concerns are that battery technology goes faster and arrives quicker in the market than brush /brushless motors and speedcontroll manufacturers can follow...

It was NOT a letter to slow cars down!! Please understand this. We are searching quick solutions to decrease the immense heat build up in the cars, so that people with current systems do not have the problems mentioned in the post from Jaybo on page 3.... as this is reality. At a World's there are many tuners going around who can set a motor exactly to the limit without it blowing up...and that is why it is called a World Championship. But, racers/ customers, which are for me/Team Orion most important, should not suffer due to the current rule restrictions which stop us to develop better and longer lasting products...

Now, please give some creative solutions to make the heat build up lower... some good points where to allow cut out in body's, or allow a mechanical brake which will reduce heat by 20%. And I think these 2 points are a good and quick step in the right direction. We need to do something QUICK to avoid people spending to much money in TC Mod before this class will die.

As I am busy with my work I will not be able to answer all posts here, if you have any suggestions you can email or pm me!

Thanks,
Oscar
Oscar Jansen is offline   Reply With Quote
Old 07-12-2006, 02:11 AM   #165
Tech Master
 
johnbull's Avatar
 
Join Date: Aug 2001
Location: Malta. G.C.
Posts: 1,762
Default

I've read up to Barry's posts on page 5, so there may be something brilliant after that which I haven't read yet.

I still think there's nothing wrong with what we have at the moment, however if we really do want to slow it down, then the cheapest and most practical way is to simply to put an amp limit on cells. Well done Barry. You're not just a pretty face.

2 years ago everybody ran 7 turn motors with 3300 capacity cells. Nobody was burning motors, though 12 turn motors did burn with 3300s.

Last year we ran 3800s. The cars got faster and some guys were cooking 7 turn motors if they overgeared.

Now we run 4200s and we cook motors and speedos with monotonous regularity if we overgear. And we crash more bacause Joe Average, like me, cannot cope with the speed.

What is the single uncommon denominator. Cars remained the same, speedos got more reliable, motors remained the same. Just an increase in battery limit.

If you're going to do anything at all, just limit it to 3000mah maximum and keep it there for 10 years.

But despite all this, the entry for the most expensive, and difficult event, the Worlds, was oversubscribed months before closing. So where's the problem?
johnbull is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
2006 Ifmar 1/12th & 1/10th Istc Electric On-road World Championships Danny Teh Malaysian R/C Racers 1 02-16-2005 10:38 AM
2006 Ifmar 1/12th & 1/10th Istc Electric On-road World Championships phlim Singapore R/C Racers 3 02-16-2005 09:52 AM
2004 IFMAR ISTC & 1/12th On Road Worlds at Full Throttle Speedway AdrianM Electric On-Road 2162 12-29-2004 04:09 AM
2004 IFMAR 1/12th and 1/10th ISTC ELECTRIC TRACK WORLD CHAMPINSHIPS Marcos.J Electric On-Road 55 02-10-2004 09:05 AM
2003 Ifmar ISTC 1/10 on road???? Wilfred Electric On-Road 2 09-01-2003 05:39 PM



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 07:04 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net