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Old 10-02-2009, 08:43 AM   #1
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Default What happens when different winds are geared for same speed?

Pardon my newbness, but I couldn't find the answer anywhere.

It is my understanding that the higher the motor wind numbers are, the lower the kV but bigger the torque, right?

..So what's the difference between, say, a 10.5 motor and a 13.5 motor that is geared for same top speed?

If my calculations are correct, a novak 10.5 in a touring car with FDR of around 5 would have top speed of 40mph. I can gear a 13.5 in low 4's and achieve the top speed right around there. In a case like this, what kind of advantage would the 10.5 car have against the 13.5 car?
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Old 10-02-2009, 08:46 AM   #2
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Originally Posted by PrimeAKF11 View Post
Pardon my newbness, but I couldn't find the answer anywhere.

It is my understanding that the higher the motor wind numbers are, the lower the kV but bigger the torque, right?

..So what's the difference between, say, a 10.5 motor and a 13.5 motor that is geared for same top speed?

If my calculations are correct, a novak 10.5 in a touring car with FDR of around 5 would have top speed of 40mph. I can gear a 13.5 in low 4's and achieve the top speed right around there. In a case like this, what kind of advantage would the 10.5 car have against the 13.5 car?
The 10.5 will accelerate faster. In other words, they may have the same top speed, but the 10.5 will get there faster.
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Old 10-02-2009, 08:55 AM   #3
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The 10.5 will accelerate faster. In other words, they may have the same top speed, but the 10.5 will get there faster.
Why? Since the 13.5 has higher torque, wouldn't it negate the taller gearing?
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Old 10-02-2009, 08:56 AM   #4
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Punch!
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Old 10-02-2009, 09:33 AM   #5
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Originally Posted by PrimeAKF11 View Post
Why? Since the 13.5 has higher torque, wouldn't it negate the taller gearing?
The key is to understand that RPM and/or Torque are not the numbers that matter most -- POWER is what you are after...

In your gearing example, you have geared the motors based on RPM to get to the same top speed -- you have not factored in the simple truth that the 10.5 has more POWER, which as someone else noted is seen as "PUNCH" on the track. Torque is multiplied by the gearing also, so the 13.5 may have more torque, but it is working against taller gearing (lower numeric ratio) -- the 10.5's torque is multiplied by the higher numeric ratio, which again brings us to the fact that nothing makes up for more POWER.
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Old 10-02-2009, 09:33 AM   #6
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Why? Since the 13.5 has higher torque, wouldn't it negate the taller gearing?
You're missing the fact that lower winds have a higher power potential, measured in watts. A motor with more overall power, geared to the same top speed, will accelerate faster. This is the same whether you are measuring power in terms or torque or horsepower (RPM) because the required gear ratios will balance out and you will still just be comparing motors in terms of which is more powerful.

It is also not necessarily a fact that higher wind motors have MORE torque than low wind motors. It is simply that the current low wind motors are capable of pulling REQUIRES a low gear ratio to reduce current draw in order to keep the motor from overheating.
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Old 10-02-2009, 09:36 AM   #7
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aaaah I see. That clears up perfectly. Thanks guys!
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