How to: Calculate Correct TX Throttle Curves for Jive

[Wh1teAfr1can]

I recently learned how to calculate the correct values for governing within the Jive and wanted to share. This is not my findings this is after talking with the owner of Kontronik (very smart man).

Basically you are shooting for PWMout of ~80% this gives the ESC enough overhead to manage rpm throughout the entire length of the flight. in order to calculate this you use the following formula

PWM out = 50% + (Tx% / 2)

so for a value of 65% flat curve in the TX this gives you:

50% + (65% / 2) = 82.5% PWM

This is the suggested max value.

60% is also a good value giving you the following:

50% + (60% / 2) = 80% PWM

Now this does differ from the Kosmik and Koby. They take the PWMout directly. When you put 80% in the TX thats equal to 80% PWM on both the Kosmik and Koby. This is explained in the Kosmik manual and it is a bit easier with that one to tune the PWM to your flying style by looking at the logs and observing the times at which you hit 100% PWM.

So basically keep your flat line throttle curves between 60% and 65% on the transmitter for optimal performance. And remember NEVER attempt to reduce or "calibrate" your end points in the transmitter.


Definitions:
PWM (Pulse Width Modulation) is basically the average time that the esc is in full current output mode. The higher the better here because if you are flying hard current is used to compensate for too low PWM which means excess heat. but too high is also bad because once its capped out at 100 your rpm can still drop and the esc has no ability to correct for it.

Edited: to include Koby (12/18/12)

[NRPY]

Yep. Those of use with JLog2s have been able to verify this theory is true.

[strokermtr]

Nice explanation....WA

[jhheli]

Good memory.

[Wh1teAfr1can]

yeah i had to look at the picture once or twice

[jchen]

Hi,
So does this mean that we should run no more than 65% max TC regardless whether
it's mode 4 or 6 for HeliJive ? Would that mean that Mr. Mels HS cal is no longer
appilcable unless we look at the suggeted TC at 60-65% ?

Thanks

[khermit]

What about the Koby?

I noticed that the calibrated endpoints on my DX8 for the Helijive is about 82%, whereas it is 92% for the Koby.

[Wh1teAfr1can]

Originally Posted by jchen

Hi,
So does this mean that we should run no more than 65% max TC regardless whether
it's mode 4 or 6 for HeliJive ? Would that mean that Mr. Mels HS cal is no longer
appilcable unless we look at the suggeted TC at 60-65% ?

Thanks

Yes you should run no more that 65% for good performance. Mr. Mels headspeed calc works but yes you need to only look at values between 60 and 65% with calibrated endpoints unchecked.

Originally Posted by khermit

What about the Koby?

I noticed that the calibrated endpoints on my DX8 for the Helijive is about 82%, whereas it is 92% for the Koby.

The Koby functions like the Kosmik you set values at 80% as max. please uncalibrate your throttle end points it is a useless operation and will make any numbers that i give incorrect. as i have explained before the Jive, Koby and Kosmik learn your end points during programming so the whole idea of calibrating them is a moot point and just confusing rather than helping. It was something dreamed up by Mr. Mel and is not something Kontronik encourages or even suggests to do because it is useless.

[jchen]

Thank for the advice

[jchen]

Sorry but what about non calibrated, If we use bail out feature calibrated throttle
will not apply correct ?

Thanks again

[MrMel]

'Dreamed up by me'

Nice but wrong, totally wrong.
Internet is nice it stores a lot of info

Search rcgroups kontronik forum for endpoint and you will see the discussion already 2006 (when is same time castle came out with their guide)

Note in same search you notice a newbie MrMel asking about endpoints in 2007

Alas , no i did not invent it.
(My vids was actually based on a written document posted here on HF)

[Wh1teAfr1can]

you should never under any circumstances calibrate the throttle. when you use bail out the bottom end of the throttle is then turned into an area used for bail out only and enables a faster start up when you set your throttle hold percentage within this zone.

[Wh1teAfr1can]

duplicate

[SkyRaptor]

What about the relationship between Tx% and motor RPM ?? How to calculate it ?? (since Jive is governed and a Tx% means a fixed motor RPM)

Alex.

[Wh1teAfr1can]

A good way to start is to take the initial pack voltage which will sag very fast and probably within the spool up of the heli so taking an average 4 volts per cell at the beginning. Now there are a lot I factors that affect this an older pack will sag faster so the initial calculated headspeed will be lower. But the following formula will put you in the ball park.
((4.0Volts*# of cells * motor Kv) / gearing ratio)*PWM

The pwm of course will be calculated based on your specific controller (reference the OP post) for example for a jive 60% throtle relates to 80% pwm or 0.8 when plugged into the formula.

So for example input 60% throttle or 80% pwm on my helijive 120 in my rush 750 the gearing ratio is 9.333 the pack is 12s the motor kv is 500 so plugging it in

((4.0*12*500)/9.333)*0.8. = 2057 headspeed

this is very close to my actual headspeed but again in mode 4 it all depends on how healthy the lipo is

[mmarian]

I do not follow the "And remember NEVER attempt to reduce or "calibrate" your end points in the transmitter." I am using Jive 100LV and Jive 80HV and on both I calibrated the Tx end points to eliminate the dead area of the Throttle stick above zero. (as per MrMell video). I have the Throttle channel ATVs for 100LV at 86 low and high and for the 80HV at 79. The ESCs initialized about 2 points below these ATV points. How does this affect the calculation for the maximum value of flat TC to have enough head room for governor?? I do not have the JLog but both of my helicopters seem to be holding the HS well. In both cases I fly with flat curves set to 75%.

[Wh1teAfr1can]

Originally Posted by mmarian

I do not follow the "And remember NEVER attempt to reduce or "calibrate" your end points in the transmitter." I am using Jive 100LV and Jive 80HV and on both I calibrated the Tx end points to eliminate the dead area of the Throttle stick above zero. (as per MrMell video). I have the Throttle channel ATVs for 100LV at 86 low and high and for the 80HV at 79. The ESCs initialized about 2 points below these ATV points. How does this affect the calculation for the maximum value of flat TC to have enough head room for governor?? I do not have the JLog but both of my helicopters seem to be holding the HS well. In both cases I fly with flat curves set to 75%.

First off Mr. Mel is not part of the Kontronik team or an employee of Kontronik. All information he provided was either of his own thinking or information that was taken from Kontronik manuals and other sources that i dont know about. The majority of it is good information. The only part of the information that is false and over confusing is the idea that there are dead bands and having to "calibrate" the throttle. His videos have been taken down in most places due to the confusion.

There are no dead bands they are areas in the throttle on the lower end for example reserved for auto bail out. and as a safety buffer.

Now i will say there is no harm in lowering your throttle end points as far as functionality goes but there are several cases where it could become one.

1. you reprogram and forget to set your end points back out to 100 you now have whatever you now have the case where your 86% is now considered as 100% by your jive because it learns the end points during programming.

2. I now have no way of telling you if your throttle curve is in the correct range. without doing extra math to take a percent of a percent. and hoping that the scales remain the same. This adds an extra level of confusion that is not needed.

Now back to the throttle curves you are running. so after working some numbers you are in the correct range comes out to roughly 62% which is within the target range of 60-65%

To answer your question regarding how this affects it you have by "calibrating" the end points changed your throttle values when you input 80% in your throttle curve you are actually showing the controller 65% throttle this is again based on my conversion. This makes for a very confusing setup process.

[7.62x51]

Originally Posted by NRPY

Yep. Those of use with JLog2s have been able to verify this theory is true.

It's true.
Take a look at the picture..

PowerJive 120 in a TDR - smooth 3Dfor 5 minutes.

[mmarian]

Originally Posted by Wh1teAfr1can

First off Mr. Mel is not part of the Kontronik team or an employee of Kontronik. All information he provided was either of his own thinking or information that was taken from Kontronik manuals and other sources that i dont know about. The majority of it is good information. The only part of the information that is false and over confusing is the idea that there are dead bands and having to "calibrate" the throttle. His videos have been taken down in most places due to the confusion.

There are no dead bands they are areas in the throttle on the lower end for example reserved for auto bail out. and as a safety buffer.

Now i will say there is no harm in lowering your throttle end points as far as functionality goes but there are several cases where it could become one.

1. you reprogram and forget to set your end points back out to 100 you now have whatever you now have the case where your 86% is now considered as 100% by your jive because it learns the end points during programming.

2. I now have no way of telling you if your throttle curve is in the correct range. without doing extra math to take a percent of a percent. and hoping that the scales remain the same. This adds an extra level of confusion that is not needed.

Now back to the throttle curves you are running. so after working some numbers you are in the correct range comes out to roughly 62% which is within the target range of 60-65%

To answer your question regarding how this affects it you have by "calibrating" the end points changed your throttle values when you input 80% in your throttle curve you are actually showing the controller 65% throttle this is again based on my conversion. This makes for a very confusing setup process.

Thank you for your comprehensive reply. I am glad to learn that I am actually within the recommended range despite my confusing set up process. It was in fact very simple. Now I have very small amount of dead band on the Throttle stick after the calibration, the bail out does not work with either of my controllers, so I am happy with what I have. Thanks again for explaining it all in a logical sense.

[dl7uae]

Fredrik tried just a single explanation, suitable for Castle Creations AND Kontronik. He was not wrong with his approach, but it's just not necessary for Kontronik. That the bailout with the H/JIVE then not well adjusted, he had mentioned in his video.

Before I forget it: Merry Christmas!