4wd Corr/Pro-4 Truck REDESIGN POSTED 12/23/09

[MetalMan]

Last night I was trying to get the motor shaft out of the rear endbell, which is a super tight fit (a lot tighter than the KMS motor). The rear endbell popped off rather easily when I hit the other end of the motor shaft. This was rather fortunate because it allowed me to extract the motor shaft from the endbell with less overall effort. Now it is time to carve the motor shaft into a desirable shape.

ok, sorry for being such a noob but......

why can you direct drive a outrunner but not a inrunner? Wouldnt the motor be significantly over stressed? Why did you choose an outrunner over the inrunner....


again... i apologize in advance

[lincpimp]

Originally Posted by Andrew32

ok, sorry for being such a noob but......

why can you direct drive a outrunner but not a inrunner? Wouldnt the motor be significantly over stressed? Why did you choose an outrunner over the inrunner....


again... i apologize in advance

The two designs are radically different. An inrunner is better suited to higher rpms, has a lower pole count, and thus does not require the esc to "fire" as many times per rotation. Most escs are limited to the number of times they can fire, so most cars will use an inrunner coupled to a grear reduction device (trans and/or diff) to produce more torque. The stator is light weight, and drive is taken off the center shaft.

An outrunner usually has more than 8 poles, and more rotating mass. They are spun at a slower rpm, and are generally used to direct drive airplane props. They require the esc to fire many times during one rotation, and thus have a lower max rpm, somewhere arounf 20k rpm for most 28-42 sizes. Drive is taken off the outer can or the center shaft, which is bearing supported at one end. They make more torque, but spin slower, so they have a different gearing requirement than an inrunner.

Inrunners will always be more popular for conversions as their operating speeds are very similar to the nitro engine so similar gearing can be used. 4 pole designs like the neu come closer to providing more torque while still retaining the higher operating speeds, and lightweight rotating components.

sweet, learn something new every day