JMRCA change touring rule to 4cells! Is this the future?
 

JMRCA (Japan racing org) just announced rule change with 4cells (4.8V) maximum.

Google translated:
URL: http://www.jmrca.com/jmrca_news/2006rule.html

Just like what we had in 1/12 EP with 4cells maximum nowday, is this gonna be the future of EP touring? 4cells maximum? This is interesting because 4cells means a huge redesign for everyone. :tire: :tire: :tire: :tire:

I already heard some T2 guy yelling..... :deathstar

Translated Page

Amendment of competition rule


11th chapter 1/8 scale * engine * off load * car
11 - 6 technical specifications
11-6-3 body
The F front * window must be transparent or translucent.
11-6-4 wing
@ wing maximum measurement
Breadth maximum: 215mm largest cord/code: 77mm 15th chapter 1/10 electromotive touring * car
15 - 3 technical specifications (expert * class)
15-3-8 wing
The E wing and the spoiler, the wing veneer than the body last section it is higher than rear 10mm, and the terrestrial 115mm to the position where does not have to protrude even at part.
The F wing cord/code length... within the 40mm, breadth maximum... makes within the 190mm
15-3-11 it is heavy quantity
4WD (4 wheel drive car above) * 1350g, 2WD (2 wheel drive car the above) * 1250
g 15-3-15 battery
The C maximum of 4 cells (the 4.8v) to you can use.
15-4-19 competition time
As for expert * class circumference race/lace 5
minutes 15 - 4 technical specifications (sport * class)
15-4-8 wing
The E wing and the spoiler, the wing veneer than the body last section it is higher than rear 10mm, and the terrestrial 115mm to the position where does not have to protrude even at part,
The F wing cord/code length... within the 40mm, breadth maximum... makes inside the 190mm
15-4-19 competition time
As for sport * class circumference race/lace 8 * * Concerning the battery * *
Use is recognized only, only the product which receives the approval of the JMRCA with the product which is sold to March 31st of 2006 2006. 2007 being sold to December 31st of 2006, it makes the product which receives the approval of the JMRCA.

January of 2006
JMRCA

They race 8 minutes there.....so going to 4 cell makes sense, as a 4 cell pack will last longer than a 6 cell (some weird form of electrical theory.....but it's true).......

Later EddieO

4 cells don't last longer than 6 cells. They both have the same amp hour rating. It just seems like 4 cells last longer because you can't draw as much current with a given motor. 4 cells is just about the dumbest thing that could possibly happen. Other areas of RC already know that low voltage is not the way to go, why can't ours figure it out.

Why? It worked in 12th scale.

Hi,

@EddieO: From what I can read they changed the rules to 5 minutes.

@Topic: In my opinion a good idea. Today's cars and (rubber) tires can't get the power down on the road and the wear on every part increases. Just my thoughts..

Cheers
Chris

1/12th is a different story. They were overloaded weightwise with 6 sub c cells. They would still be faster and more efficient with higher voltage and lower current. I have run 1/12th using 6 4/5 sub C cells and it performs well. A 11.1V lipoly would be great because you wouldn't have to use 12 AWG wire to the rear pod. 1/10th touring cars are bulky and inefficient compared to pan cars and the drop is voltage will definately hurt performance. One simple equation explain this

P= (I^2)*R This is the power lost in parts like FET's, wire , motor windings, and inside batteries. A reduction of voltage to 2/3 of its original value will cause you to increase current to keep the same power output. So if you were drawing 30A at 7.2V, you will now have to draw 45A at 4.8V. So, your current has to go up a factor 1.5 to compensate. Since power lost is proportional to current squared, your losses have gone up by a factor of 2.25.

Ploy for lipoly? Makes sense.

Wouldn't a 4cell have lower amp draw due to lower weight though? Which also would have an exponential effect on the decrease in losses?

Plus there are so many other areas that suffer from more weight and speed regardless of current. Tires, parts, heck... even the track barriers. lol

If 100% of the car's weight was the battery you would see exponential gains in performace by reducing the cell weight to 0.

Barry Baker will be happy. He's been on the 4-cell sedan bandwagon for a while.

Yes, they do last longer. ;) (Sorry I couldn't resist)

4 cells have lower voltage which means whatever they're moving or driving or something, moves slower. Since it's moving slower it uses fewer ampers and since the cells have the same amp hour rating they lasts for longer time.

This is exactly what you said, you just draw different conclusion.

what's good here is we get to see how it works out for another racing community (japan) before we (U.S.) make any kind of decision on 4 cell racing. Let's see how this plays out before we condemn or accept it here.

After destroying several Reedy Brushless motor systems at the novak race, Barry should be the last person to want lower cell counts. Higher Current = more heat = lower life time electronic stuff.

I think JMRCA wants to keep a step ahead of battery manufacturer, with the IB vs GP war going on, we will see 5000mah and 4T mod very soon. How many people can drive that? not to mention additional tyre and motor wear even with new motor technology. It make sense to cut power if Mod class has to survive. The situation is similar to 1/12 in 1998-99 when they change from 6cell to 4cell worldwide. This year On-road Worlds in Italy we may see 4200,4300mah with 5-6T motor, the horsepower will be ridiculous.

Exactly. :nod: . Glad to see someone's turned their brain on this morning!