RC-Monster Forums - View Single Post

RC-Monster Mike · 05.14.2005, 05:01 PM

All this talk of "paper power" really isn't what gets the truck moving. the rated watts of the motor in the specs really doesn't have anything to do with how much power it gets to the ground. The lehner basic motors, for example, are rated at 700 watts, but folks have measured power output in excess of 2000 watts with those motors (obviously not for extended periods of time!). I would surmise that given the same KV value in a motor, the motor that has higher efficiency would ultimately have the highest power output due to less power loss, and the smaller motor will almost always have more "pep" in the short term. Furthermore, I would bet that a little lehner basic motor with the same Kv value as the big maximum and the same gearing on the same vehicle would probably kick its but in a race, simply because the motor itself is smaller and has less of its own mass to move(accelerate). Long term, this would not be a good idea, as the small motor (rated for 700 watts=continous watts) would eventually burn up from trying to create all the power for a long time. The advantage of the larger motors is their ability to deliver the power continuously(in other words, the larger motors won't burn out as easily because they can handle more load over time). Also, a 2 pole motor can achieve twice the rpms with any given speed controller, for pure speed, my money would go to the 2 pole motor every time. The 4 pole motor in theory has more torque and certainly puts the power out smoother at low rpms, but is also much harder on controllers.
Having stated these opinions, I think to achieve more power/speed in your truck, Ryan, you could consider a slightly smaller motor (1930 for example, which is between the "L" and "XL" Feigao/hacker motors in size) with higher voltage. Perhaps even using smaller cells (like gp2200 cells-since you are opposed to LiPo) to minimize the weight (20 of these cells can deliver the needed power at the weight of around 14-15 3300 cells, along with fitting easily on the g-maxx chassis). You wouldn't likely lose much, if any, runtime with the smaller cells (they have a similar energy density vs. the larger cells) and a slightly slower motor. Higher voltage is usually more efficient (wire can tranfer more voltage than it can amperage) and can more easily put out the power.

Just more points to ponder! :)

	(#17)
RC-Monster Mike Site Owner Offline Posts: 4,915 Join Date: Nov 2004 Location: PA	05.14.2005, 05:01 PM All this talk of "paper power" really isn't what gets the truck moving. the rated watts of the motor in the specs really doesn't have anything to do with how much power it gets to the ground. The lehner basic motors, for example, are rated at 700 watts, but folks have measured power output in excess of 2000 watts with those motors (obviously not for extended periods of time!). I would surmise that given the same KV value in a motor, the motor that has higher efficiency would ultimately have the highest power output due to less power loss, and the smaller motor will almost always have more "pep" in the short term. Furthermore, I would bet that a little lehner basic motor with the same Kv value as the big maximum and the same gearing on the same vehicle would probably kick its but in a race, simply because the motor itself is smaller and has less of its own mass to move(accelerate). Long term, this would not be a good idea, as the small motor (rated for 700 watts=continous watts) would eventually burn up from trying to create all the power for a long time. The advantage of the larger motors is their ability to deliver the power continuously(in other words, the larger motors won't burn out as easily because they can handle more load over time). Also, a 2 pole motor can achieve twice the rpms with any given speed controller, for pure speed, my money would go to the 2 pole motor every time. The 4 pole motor in theory has more torque and certainly puts the power out smoother at low rpms, but is also much harder on controllers. Having stated these opinions, I think to achieve more power/speed in your truck, Ryan, you could consider a slightly smaller motor (1930 for example, which is between the "L" and "XL" Feigao/hacker motors in size) with higher voltage. Perhaps even using smaller cells (like gp2200 cells-since you are opposed to LiPo) to minimize the weight (20 of these cells can deliver the needed power at the weight of around 14-15 3300 cells, along with fitting easily on the g-maxx chassis). You wouldn't likely lose much, if any, runtime with the smaller cells (they have a similar energy density vs. the larger cells) and a slightly slower motor. Higher voltage is usually more efficient (wire can tranfer more voltage than it can amperage) and can more easily put out the power. Just more points to ponder! :)