Kontronik 65% throttle curve?

[beans07]

Hi just wondering if the recommended 65% throttle curve is when the throttle ATV/Endpoints are calibrated or when running them at 100%??

[Stolla]

if I understand your question its uncalibrated as per mr mels videos, i.e. default but since you have to set endpoints its actually calibrated to tx albeit it not real values, so kontronik 65 is approx 85% real value.
While on this subject, although kontronik recommends 65%, its not always possible to run at this value for your aimed headspeed, you need to have matching components. For instance a monster motor with low c lipos will ruin the lipos very quickly as gov will place extreme demands on the lipo, similarly 65 c lipos won't do much if the motor its not strong enough, doesn't matter what the gov does motor will bog.
The best option in such instance is to change to a smaller pinion and run lower headspeed . Usually people change to smaller pinion then up percentage to keep headspeed same
The heli will perform better with lower headspeed at 65% vs higher at 85% as far as governing goes, if it doesn't your motor and, or lipos aren't up to scratch.

[beans07]

Thanks for the reply.

It is for Rave 450 running 3s 65C TP 2250mah packs. I am aiming around the 2900-3000 HS.

I do agree about changing the pinion and that is what I am determining at the moment. Which pinion will be best for the HS I need.

So 65% is the value when you have left the endpoints at factor 100-100?

[SimStream]

Yes

[Stolla]

well are you using jive or jazz, jazz may be different, I don't know

[wanderer56]

I guess this is just for the Koby series, but:

The KOBY RPM control is adjusted automatically to
the application during the first start of the motor
after connecting the battery. It is recommended to
set 0° pitch to ensure relatively constant RPM
during each flight. To start the motor push the slider
towards full throttle. The KOBY will smoothly
increase the motor RPM in a few seconds. As soon
as the designated RPM is reached the KOBY
switches over to close loop speed. The closer the
slider position is to full throttle, the higher is the
designated motor RPM. KONTRONIK recommends
setting minimum RPM at 80% of full PRM.

Mode-Standard Settings
Cell type:: LiPo
Speed up: smooth, 12 seconds
Speed characteristic: rotorhead
Undervoltage
disconnection: Slow down
Brake: inactive
With the slider back in motor-off position the
motor will be switched off. Be aware not to
do so in flight, otherwise it would take some
seconds to start the motor again.

[7.62x51]

I mounted a Koby 40 onto my EMBLA and set three flat curves, 40%-50%-60%, obtaining 2700 - 3000 - 3250 rpm.
Governor works as fine at 40% as at 60%, no issues until now.
I left uncalibrated endpoints an did some small tweak to the gov parameters via progdisc.

[jmb2232]

So if 65% is the recommended value running 100/100 endpoints, what is the corresponding percentage when running calibrated 82/82 endpoints? The answer to this question will explain a lot for me. Thanks.

Mike B.

[7.62x51]

About 68% or 70%

I discovered the difference between the percentage in tx and that "felt" from the Jive after connected a Jlog. So i redid the Jive setting, mode 1 - mode 4, rising the travel a 100 and then both curves was the same.

[mmarian]

Originally Posted by 7.62x51

About 68% or 70%

I discovered the difference between the percentage in tx and that "felt" from the Jive after connected a Jlog. So i redid the Jive setting, mode 1 - mode 4, rising the travel a 100 and then both curves was the same.

I do not follow. Maybe I can rephrase the original question. As explained in another thread recently, the true Power output from Jive ESC do not match the Tx % of throttle curve. Apparently the 100% Jive output is reached at around 80% of Tx throttle curve - hence the recommendation of Tx throttle curve (flat line) not exceeding 70% in order to leave enough headroom for governor to work properly. So, the question is that if we "calibrate" the Tx as per Mr.Mel video and have the Throttle channel endpoints set to L80 and H80 (or 82), at what % of throttle curve we reach 100% Power output from the Jive ESC, as per JLog??

[SimStream]

As a rough guide, if you calibrate your throttle curve to 83/83 you are reducing by 20 percent. So if you set your jive throttle at 80 then the same throttle setting uncalibrated would be 80 less 20 percent. Roughly 64.

So calibrated 80 equals non calibrated 65.

Thats my understanding anyway

[mmarian]

Originally Posted by SimStream

As a rough guide, if you calibrate your throttle curve to 83/83 you are reducing by 20 percent. So if you set your jive throttle at 80 then the same throttle setting uncalibrated would be 80 less 20 percent. Roughly 64.

So calibrated 80 equals non calibrated 65.

Thats my understanding anyway

That would be a logical conclusion but unfortunately logic does not always work and I am afraid this is one of the situation when only data from JLog could provide a definitive
answer ....

[7.62x51]

Originally Posted by SimStream

As a rough guide, if you calibrate your throttle curve to 83/83 you are reducing by 20 percent. So if you set your jive throttle at 80 then the same throttle setting uncalibrated would be 80 less 20 percent. Roughly 64.

So calibrated 80 equals non calibrated 65.

Thats my understanding anyway

Using a Jlog i found exactly the inverse.

[jmb2232]

Yeah, I didn't think we could tag it with a mathematical relationship. Looks like I'll just try 65% with a 100/100 ATV, tach it, and then calibrate to my normal 82/82 and just trial and error the throttle curve value until I get the same headspeed. Brute force method I call it. Normally, I run my throttle curves at about 65-70-75 so I don't think I'm stressing the Jive. Also, it looks like I'm in a good range for the Jive in a "calibrated" setting. Maybe I should just fly and stop worrying about it.

Mike B.

[MrMel]

Originally Posted by mmarian

That would be a logical conclusion but unfortunately logic does not always work and I am afraid this is one of the situation when only data from JLog could provide a definitive
answer ....

Its correct...

If you adjust atv you reach max at 100%

if you do not adjust you reach at 80%

except some radios, which only add 10%..

Do note that its not PWM though as it has a slight overhead too so there is one more level

Im betatesting a version of my calc now where you can select yes/no if you have it adjusted, if not it shows like 63%, 67% etc with 80 as max

[OverTemp]

There's a simple experiment you can do using the servo monitor screen to determine the relationship... I'm working on a mathematical formula to demonstrate the relationship right now... almost done actually. Maybe Mr Mel can use it in his head speed calculator... sure I won't get a by-line though What I do know for fact is that 80% cal does NOT equal 65% non-cal... nothing could be so simple!

[MrMel]

Originally Posted by OverTemp

There's a simple experiment you can do using the servo monitor screen to determine the relationship... I'm working on a mathematical formula to demonstrate the relationship right now... almost done actually. Maybe Mr Mel can use it in his head speed calculator... sure I won't get a by-line though What I do know for fact is that 80% cal does NOT equal 65% non-cal... nothing could be so simple!

It IS that simple... it's just that as PWM is not linear it needs two calculations, you cannot do it in one calculation alone, but yes, I will do it in the calc I think, I have a beta running.

What people mistake is that you have 3 things
Radio throttle
Jive throttle
Jive output PWM

[OverTemp]

I’m going to lose cool points for this, but I couldn’t let this just be an unknown. I just have to figure things out. Mr Mel will probably even think I’m a geek.

There IS a formula to convert between calibrated and not calibrated. I came up with it, but it’s not terribly simple. However, if anyone can disprove it please do! I’m putting it here because this thread is likely to show up in a lot of searches.

Formula:
X = (T-50)*(100/82)+50 = Throttle to set on a calibrated radio to equal the setting “T” on a non-calibrated radio.

CAVEATS:

1) The JIVE doesn’t know 100% on your radio. It knows only where your endpoints were when you programmed MODE 1 (RESET MODE)… it learns them. If you programmed MODE 1 with your endpoints at 60%, it will arm at 80-82% of 60%, or 50% on your ATVs (had this happen 2 days ago). If your endpoints aren’t exactly equal when you program MODE 1, then your gov settings will never make sense. To get the usual numbers, be sure your ATVs are at 100% and your throttle curve endpoints are 0% and 100% when you are programming MODE 1. Why the JIVE does this 80% business and not just use the endpoints it just learned as the actual endpoints is beyond me, but that’s what happens, verified through experiment (a frustrating one!).

2) On your radio, 100% ATV isn’t 100% of travel. In fact, calling it a percentage really is a misnomer, but one we are stuck with. On a JR, +100% is 100 steps out of 150 possible steps between 1500 and 2100 microsecond signals sent to the receiver. -100% is 100 out of 150 steps between 1500 and 900 microseconds. Total, there are 300 possible steps to set between 900 and 2100 microseconds. On a Futaba you have +/- 140 steps (280 total). On multiplex it’s +/- 110 steps. I don’t know airtronics, etc… you’ll see in the end though that it doesn’t matter. This point on the steps is brought up for your completeness of understanding.

3) Assume JR for this next section. Your throttle curve percentage is a really a percentage of the number of steps you assigned with the ATV, but with a quirk. 50% on the curve is always whatever point your sub-trim is set at, and it the point where your two ATVs meet in the middle. This really complicates the math. What we care about is the throttle curve distance from 50%, not the curve value between 0 and 100. To figure out the number of steps we are at between 0 and 150 on the positive side of the travel, we have to subtract 50% from the throttle curve setting, multiply by 2, then multiply by the ATV setting. Example, if your ATV and throttle curves are at 100%, then 2*(100-50)*100/150=100/150 steps positive. If your ATV is at 82%, then a 100% throttle curve is 2*(100-50)* 82/150 = 82 out of 150 steps positive. 75% would be 42 out of 150, 50% would be 0 out of 150, etc… When we go below 50% we go to the negative side of travel.

OK… so that’s the background… the math is a pretty simple ratio that looks complicated.

Assume:
R=the number of steps a radio brand has,
X = The throttle curve value of a calibrated radio with ATVs at 82%
T = the throttle value of a non-calibrated radio with ATVs at 100%
Subtrim be at zero
+/- ATVs be the same

Then:
2*(T-50)*(100/R) = actual signal = 2*(X-50)*(82/R)

The “R’s” and “2’s” cancel out (meaning brand of radio doesn’t actually matter), so the end result is

X=(T-50)*(100/82)+50

If T=65% non-calibrated, then chugging the numbers

X=(65-50)*(100/82)+50 = 68,

A calibrated radio will need to be at 68%. Pretty neat, and pretty simple in the end.

So… validate it. If you have an 8FG, your servo monitor will show a number under each bar. This number is absolute… it doesn’t change step values or anything with radio settings… it represents the actual signal steps, between -140 to +140, that are being send to your receiver.

1) Set your throttle curve to 65% and your throttle ATVs to 100%. Look at the number on the servo monitor screen. Record. Mine says 29.

2) Set your throttle curve to 68% and your throttle ATVs to 82%. Look at the number on the servo monitor screen. You’ll see it's the same as the last step (again I get 29), proving that a calibrated radio at 68% curve is sending the JIVE the same signal as a non-calibrated radio at 65% curve.

Pretty neat.

The most disturbing thing anyone looking at this will find it that it is not linear. For example, 65% non-cal equals 68% cal… a 3% difference. BUT, a 75% non-cal equals 80.5% cal… a 5.5% difference. The further you get from 50% throttle curve, the bigger the difference between cal and non-cal becomes! But, this was all verified using a radio. I'm sure Mr. Mel has it right!

[MrMel]

Yup, But that was the most complex post for what I have as 2 lines of code in the calc I have to say

[OverTemp]

I know... I was hoping to explain to all, not just you, so people understand why... we get better by bending our brains and this a little brain bender people might be interested in more than 2 trains leaving LA and NY at 50 mph and 35 mph....

The formula itself is one line really, but it looks whacked if you don't understand it. Thought some among us might like the reasoning, and I enjoy working on my writing