Linear throttle curve for Mamba Max - RC-Monster Forums

DrKnow65 · 07:07 PM

I have been playing with the exponentials and programming on my Mamba Max, it seems to me that part of the problem people have with racing this unit is the power produced v.s. the travel of the trigger.

It seems to me that 70% of the power the MM makes comes on in the last 20% of the trigger throw.

I'm getting a much more linear feel with the exponential cranked way positive (bringing on more power sooner in the throttle travel) which gives it a much more "controlled" feel from half throttle on.

I'm not sure if one could "dyno" a brushless motor/esc, and figure out what power output coresponds to what throttle position (or power curve on the mamba max software) to get an actual "linear" throttle...

Any ideas?

sleebus.jones · 11.21.2007, 09:50 AM

You could do that with an Eagletree. I think there's an addon for throttle position, and you can get motor RPM, so you could check it that way.

DrKnow65 · 11:15 AM

I thought about an eagletree but then I figured there were so many variables.

I suppose if I used an eagletree (throttle signal, amps, and RPM) with a constant load (say a propeller) on a bench it would get me the info needed, but then how to use the numbers to figure out what the curve needs to be?

Is a propeller a constant enough load? (I would think it spins very easily until it has a enough rpm to to have a little pressure forming) Mabey a brushed motor shaft to shaft with the brushless would be a better load?

The major fault at this point is not having an eagletree :) But christmas is on the way, and I've already used the B-Day excuse to pick up a Dark Impact (Dec9th)

sleebus.jones · 11.21.2007, 11:27 AM

No, a prop or another motor is not constant enough of a load. However, drag is very easy. :)

Mount the motor someplace solid, so you can have the shaft hang off the end of a table. Get some string, make a few (two or so) loops around the shaft, and tie one end to something solid, and then hang a weight on the other free end. Instant drag! You can also adjust the load by adding more weight on the free end.

Eagletree is VERY nice. The V3 is going to be out soon, handles higher voltage, and there's now a 150A version available. I love mine, worth every penny.

DrKnow65 · 11.21.2007, 11:35 AM

Doh (i.e. Homer simpson), suppose I can overengineer anything :) String and a weight, heard a quote fom some genius recently

"With all the new inventions that have happened in the last twenty years it will take the smartest people in the world sixty years to make them simple enough for the common person to use."

glassdoctor · 11.21.2007, 01:03 PM

MY $.02

I love the eagletree... it's a tough little bugger. I even melted the wires off mine when my esc/motor shorted out and it still works after a little repair job.

MM: I actually pull the throttle curve to the negative to smooth out the bottom of the power band. I never noticed the top end being too much. I think the bottom end has too much power. :)