Whatcha Think of This
 

the true rc 4000mah 5s lipo, and the true rc 120a ESC? its rated at 6s lipo, so should work fine, ill be using a feigao 9xl also. is this a good setup with 16/38 gearing in a erevo with the tekno kit?

Just a thought you might be close on RPM limit for Feigao motors when straight of the charger...

Instead run a 10XL, 11XL, or possibly a 12XL and just gear up. Feigao's don't like high RPM's...

which would be the best out of those 3 motors?

Hmm I have never seen that ESC before....anyone tried it? A quick search on the forum returned nothing....

120A 6S for $110 seems almost too good to be true?

There are usually three issues with using airplane ESCs:

1) Many don't have reverse and/or brakes. Not a big deal if using a servo for brakes and don't use reverse anyway.

2) Many are made for aircraft radios. A air radio "neutral" would be a car radio reverse/brake. This can be fixed by using a "pistix" adaptor (or something like that), which translates a car radio throttle signal to emulate that of an air radio.

3) Airplane ESCs don't have the burst amperage rating that a car ESC does. Generally, an airplane pulls more average current, but doesn't peak that much. A car pulls less average current, but can pull lots of burst current (up to 10x average current). Ever notice that the ave and max current ratings of an air ESC is pretty close, while a car ESC's burst current is substantially higher than its "working" current? However, as long as you keep this in mind, you can pick the approriate ESC.

to have an airplane esc run succesfully, you need mechanical brakes (this can be don trough a Y cable, to simple devide the throttle channel to the brake servo and the speedo)

and like Brian says; most are made for stick transmitters;

the problem is that normally 0rpm on an airplane is -50% of the throttle possition of a pistol grip. The pistix changes this.

well ill prolly just use a mamba max because itll be easier. how would it work with a 9xl on 4s 5000 mah?

Probably like a charm, but i've heard some stories of mm controllers not being capable of handling more than 3S.

well, I've olny heard that they cannot handle more than 4s but never only 3

If it won't handle 4s, then it won't handle 12 cells since they have the same nominal and max (right off the charger) voltage. And if it won't handle that, I'd call Castle saying the ESC is faulty since it's not running its rated voltage...

right, it should run 4s. and it will. :diablo: