Upcoming Castle Outrunner Motors

[Sammus]

Originally Posted by lincpimp

An outrunner in place of the center diff does have some benefits, but the lack of a slipper and any sort of primary gearing will deter most. I personally think that inrunners, or possibly a hybrid motor, will suit most racing and higher speed cars better.

Now an outrunner in a crawler is much better than an inrunner due to torque. I have a few outrunner crawlers and they are beasts. They are geared low. 10mph max, and only run 3s lipo. Much better than an inrunner, and more power than a brushed motor.

It all depends on what you need.

when sik said "A super low kv inrunner would make ALOT more torque" I thought he mean than an equivalent size/kv outrunner. Now I think I may have misinterpreted his response.

At any rate, it was Mike's narrow window of efficiency thing that got me. I want my cars to be efficient in as wide a band as possible. I think even when crawling you vary the motor speed coniderabley.

So where is the trade off? a 4 pole inrunner and 12 pole outrunner, of similar size and Kv. The inrunner I guess makes more power and can rev harder without anything going wrong. The inrunner is efficient over a much wider rpm range than the outrunner. The inrunner can run on a much higher voltage than the outrunner because its max rpm is a lot higher. The outrunner has more torque.

How much more torque? Te inrunner would have like a million winds to get into the 500kv zone so would have heaps more torque at the rotor than any inrunner we're used to. Furthermore, since the inrunner revs so much harder, gear the inrunner down to get the same rpm as the outrunner, you further multiple the torque.

Has anyone got any torque or power curves comparing similar sized motors?

The only application I can find them useful is in airplanes...when rpm is nearly constant, and everything has to be lightweight, so best do without the gearbox (ie low kv is an advantage).

Don't get me wrong, I don't want to argue for the sake of it, I am genuinely interested. But noone has really given anything more than their opinion on why they might of advantage in a car. A few claims that weren't backed up.

Also, I'm not knocking castle either, since I'm certain these outrunners are for their air guys (us car people aren't the only ones obsessed with castle gear you know :P)