powerjets

My Feedback: (1)

On the newer ECU there is an option to set the Throttle stick curve.
Mine was set on 3, but I'm not sure what it does and which way is more or less exponential,
anybody know ?
thanks

powerjets

My Feedback: (1)

C'mon guys,
its in the limits menu..

furloughed ual

My Feedback: (31)

I believe it is the expo curve. If I remember correctly, it goes from 0 to 5. 0 is a softer curve and 5 is more linear with the throttle stick. I've only had an rx in my posession for 1 run so far, but if I recall, a setting of 5 gives you more thrust for less throttle stick movement in the lower RPM range.

Go out ang try it. Set it to 0 then set it to 5 and see what the difference is, you're not gonna hurt anything. If you dont like it, set it back to the default value of 3.

Carsten Groen

I'm always running the default on my JetCat engines, and using positive expo on my transmitter (Futaba 14MZ/18MZ)
On P160SX I usually run about +25% and on my P200SX around +40%

powerjets

My Feedback: (1)

correct from 0.1 to 5.0
I feel on 3 there is hardly any power on midstick...
I'll see what it does on 5 then .
thanks

furloughed ual

My Feedback: (31)

from the manual:

"Throttle stick curve, factory setting is 3.0 herewith the thrust and the throttle stick position proceed proportional. At the value of 1.0 the PRM proceed proportional to the throttle stick position."

So....in my translation, it appears the higher the number, the closer the THRUST and throttle stick position match....25% throttle should equal approximately 25% THRUST, which would of course be a higher RPM than 25% of the available RPM.

A lower value matches the throttle position with RPM....25% throttle equals 25% RPM, which would mean somewhere around 10% thrust (or whatever the actual number would be), since the thrust curve on a turbine is very shallow until you get to around 70-80% of the available RPM.

With that being said, if you make it more linear, you need to be easier on the throttle stick or slow the acceleration a bit as you are in effect asking for a faster spoolup. More thrust for a lower throttle setting is gonna have to make the turbine spin a faster RPM at a lower throttle stick position.

Make sense?

Ryan
Jet Cat USA rep.

powerjets

My Feedback: (1)

Correct, seems to make sense,
I did not have this info in my manual,
but what I'm looking for is to cruise at midstick with sufficient power to maintain energy, looks like 5 is for me.

S_Ellzey

Actually that does not make sense. The ECU should always limit the acceleration to what is achievable. Regardless of what you ask it to do, the time from say 10% to 25% should be the same. The only difference here should be where the stick is to finially get to 25%, otherwise if I slam the throttle open from idle the engine would die regardless of the throttle curve in use.

furloughed ual

My Feedback: (31)

In theory yes, you are correct. It should ( and does) limit acceleration. I was trying to help lay out some facts to explain the question. Trying to paint the big picture. I haven't seen an ECU out there on any of the major brands that is 100% automatic and self regulating. If you make the wrong or too aggressive adjustments, it won't run optimally.

highhorse

My Feedback: (2)

Staying out of the ECU settings, I simply used expo to flatten the lower end of the curve. In my case the jet was hard to taxi because just a few throttle clicks would change the thrust from "not enough to move in the grass" to "oops, hauling butt in the grass". A tweak of the expo and it became much more manageable.

Two cents.

powerjets

My Feedback: (1)

The thing is, the default setting in the ECU is 3, which is not my preference.
upto 60 % stick hardly has thrust and then it comes in too strong, it is too hard to find the sweet spot for cruising.
I use expo in my transmitter and its still too steep.
My point is; before this option was available , it was fine on my transmitter expo, now it is not.

DavidR

My Feedback: (1)

Actually in theory and in reality the throttle stick position only controls what the ecu sets the pump voltage at. The acceleration time of the pump is does not change with throttle stick position no matter what kind of curve you have. If you want to change pump acceleration curves you do that a little deeper in the ecu.

DR