Craig!

The way I read your post, it looks to me like you are comparing the a sport tuned 27 turn motor ( with advanced timing) Vs a standard 27 turn kit motor. Not a 540 Vs a 16 turn.

When you make all other things equal, i.e., gearing and number of motor winds, then the emphasis falls on available voltage.

Available voltage will overcome the difference between the two motors, you can run a silver can kit motor with a 16 pinion and 12 volts, I can run a sport tuned with 20 pinion and 6 volts and you'll be faster in a straight line

A kit motor with a 20T pinion (largest that fits on a mini) and fresh 4200's will be as fast if not faster than a sport tuned geared the same using a poor 1800 mah battery -

Both motors using a 20t pinion will draw very similar current as they are 27 turns.

Electric motors use the most current the highest load.

At this a higher load , typically when the car comes off the corners, the motor with the higher available voltage ( V/R=I ) will develop the higher current and thus the greater torque ( more magnetism around armature winds) - once this is overcome, the higher voltage will also develop more rpm.

If you are looking for equality,maybe limit the 4200/ sport tuned runners to using a 18 pinion

Lou!

The way I read your post, it looks to me like you are comparing the a sport tuned 27 turn motor ( with advanced timing) Vs a standard 27 turn kit motor. Not a 540 Vs a 16 turn.
I am comparing the 53068 Tamiya Sport Tuned Motor to a 540 Johnson/Mabuchi that comes in the kit. The Sport tuned motor is 23 turns, the standard motor is 27 turns.

When you make all other things equal, i.e., gearing and number of motor winds, then the emphasis falls on available voltage.
Agree

Available voltage will overcome the difference between the two motors, you can run a silver can kit motor with a 16 pinion and 12 volts, I can run a sport tuned with 20 pinion and 6 volts and you'll be faster in a straight line
Is this a statement on the relationship between supply voltage and motor output? If I use that analogy then all other things being equal, you will be faster in a V6, than I will be a in a V8 running on 4 cylinders. Handy to know, but otherwise useless information.

A kit motor with a 20T pinion (largest that fits on a mini) and fresh 4200's will be as fast if not faster than a sport tuned geared the same using a poor 1800 mah battery
4200mAh and 1800mAh has no bearing on motor speed. If the fresh new 4200 and the poor old 1800 have both the same voltage, then you will get the same motor speed, end of story. Although the 4200 will maintain that speed for a longer period.
If you are trying to say that a really old pack with a low terminal voltage will not perform as well as a new pack with a higher terminal voltage, then I agree.

Both motors using a 20t pinion will draw very similar current as they are 27 turns
There is a huge difference in current..
The 23 turn sports tuned motor current drain at best efficiency is 12Amps
The 27 turn stock motor current drain at best efficiency is 7.9 amps for Johnson, 5.9 for Mabuchi.

Electric motors use the most current the highest load
Agree..

At this a higher load , typically when the car comes off the corners, the motor with the higher available voltage ( V/R=I ) will develop the higher current and thus the greater torque ( more magnetism around armature winds) - once this is overcome, the higher voltage will also develop more rpm.
The motor with the higher available voltage will draw more current to overcome to load placed on it, and therefore develop more torque, motors can not develop current, unless you apply an outside force to them (e.g generator/alternator). They do however generate back EMF during the cycle switchover point, where the armature winding polarity is reversed to finish the last part of the motor revolution, this is the blue spark you see when the motor is running.

"Once this is overcome" What is to overcome? The only force to overcome to get the motor to spin is friction. You apply an voltage to the armature windings which turns into an electro-magnetic force, and the rotor is forced around in a circular motion by the opposite attraction of the permanent magnets inside the can, or in the case of coreless motors, the permanent magnets found inside the armature windings.

If you are looking for equality,maybe limit the 4200/ sport tuned runners to using a 18 pinion We can place as many limits as we like on the classes, then lets see who scrutineers and polices it at a club level race day. I am not saying it's a bad idea, but the more rules we place on them, the harder it will be to maintain.

You can't change your kit engine in Pull Start Pro or Pull Start Sport, so why can you change it in Mini?

We will never be able to make it truly even, unless we hand out control cars before the start of each race, even then there will be slight differences with batteries, motors etc.

My original point still stands in that I believe we need to provide a class where you can buy a car, not spend money on upgrade parts to get near the pointy end, and be able to have a fair race.

Craig

if there is going to be more rules & regulations for mini class at mprccc than any other club in vic what are the chances of other club racers showing up to race on the day?

what if we had 2 classes, mini stock to allow stocks to run at entry level (like stock nitro) and mini pro for all other mods for mini`s?(like other nitro classes?) depending on the numbers at race day?

cheers

Thats a great idea! Numbers might be an issue at first, but that solves quite a few issues..

I didn't think a simple question was going to attract so much interest. I really only wanted to know why we could not run the Sport Tuned Motor like MOST other clubs.
My other question was in regards to Electric touring cars, I think the rules are a little vaige.
Anyway I agree w' Prez, let's work it out @the meeting until then just run the VORTEC rules.<br><br>Post edited by: allaboutRC, at: 2007/03/29 20:48

as long as we keep rules simple and well defined for both classes it just might stop some confusion about all the rules, still keeping both classes fun/competitive and bring in a few more $$$ for the club with race entry fees/new members.
The worst out come would be loss of members/entry fees if this can not be worked out.

cheers