Originally Posted by imjonah
Tech question for you Adrian.
Technically shouldn't all 13.5 Brushless motors be identical "speed" or torque at a given RPM. The designation '13.5' is nominal isn't it? There not in fact 13.5 turns of wire in it? Isn't the 13.5 the result of using some agreed upon formula for converting KV?
A related question I assumed the two rationales for adopting Brushless were
1. greatly reduced maintenance time and costs
2. Level playing field, everyone in any given class 13.5 17.5 getting the same exact power.
also since the cost of manufacturing different brushless "winds" 13.5, 17.5 is virtually identical couldn't ESC be produced that could be programmed to match each spec, in other words one motor one ESC, click a switch to change to a different spec?
Well, BL motors are a lot closer speed wise than brushed motors were. Mainly because the rules for BL are A LOT tighter than for brushed motors. That said there is some leeway in the rules. There has to be so motor companies can innovate and make improvments over time. A very knowledgeable BL motor guru I know told me there is ~5% spread between the best and worst BL motors in any given wind. This is due to the steel used in the stator laminations, the quality of the rotor magnet, quality of the copper in the windings, how well wound the stator is...etc. There are a lot of small variables that can add up to make one motor better then another.
There are 13.5 turns or wire on each pole of the stator in our motors. There are front and rear terminated motors that dont have the extra .5 turn. This is why there are some mods that are 4.0 and 3.0 turns.
LRP's first Sphere has a motor limiting feature. It sort of worked but it was not very smooth. Speed control limiting of motor power is certainly possible. The problem is it is impossible to tech and even harder to prevent guys from cheating. So...we run diffrent motors.