"Dynamic Idle" the most useful Betaflight feature you never heard of 

How do you figure out what a good idle_min value is? LONG STORY SHORT -- take your idle%, convert it to RPM using the Motors tab, then set idle_min to 80% of that value. That is a guideline that has come out since this video was made, and it's one of the biggest questions people ask.

Never call yourself "not smart" Josh! The smartest people can take complex material and explain it simply to others who do not understand. Thanks for all you do! Much love!

Cheers. The quick video was the least I could do for how many times I’ve used your tutorials.

Such a nice and humble guy, not taking all the credit for other people’s hard work but also helping the fpv community to understand these features

Brand new to droning. I have a traxxas aton that im cutting my teeth on. I finally purchased a build kit from rotorriot.com with dji hd fpv. Take into mind i am so new that im still wet behind the ears. I enjoy your videos, they have taught me so much. Looking forward to fpv’ing!

BOOM!!!! Finally an answer, thank you Bardwell. I've been lowering idle min in order to grind and slide. Keep getting death rolls when smash technical flips, particularly with yaw. A tip! When mid death, roll you can shake it free by jamming yaw back and forth, then drawing it out and catch it.

I didn't understand how this work and what it's used for at all from this video, nice for getting attention that this feature exists though. Would greatly suggest everyone to just read what's written in betaflight documentation about dynamic idle, it's well written and super easy to understand.

Electric motors actually have max torque when starting from stall and the torque goes downwards as the RPM increases because magnetic field cannot be modulated fast enough due inductance. However, the current generation of brushless motors do not have required sensors to actually push the motor hard from stall so that's why you need minimum RPM for max performance.

I'm Learning... I learned that maybe my de-syncs are from setting my idle percentage too low... never dawned one me

Interesting as advertised! Thanks JB, these kinds of tips don't just help pilots get better, it advances the entire hobby. Shoutout to the BF devs for their work!

My understanding of dynamic idle was that it used the rpm data to make sure the motors never stalled whilst allowing a much lower minimum idle overall. This is probably useful for making last minute adjustments when flying as your quad should be less floaty.

A mounted prop will affect stall, a lot more weight to get/keep rotating, so higher torque via rpm is needed.....as you found out😎

You may not be the smartest guy, but you're a really freaking good teacher.

Just had a desync at zero throttle with my 3 inch build resulting in a crash. Enabling bidirectional dshot and dynamic idle sure enough fixed the issue. Also feel that enabling rpm filter and disabling first gyro filter resulted in much more responsive flight characteristics.

My first bit of tuning advice is always to up the min_throttle, I'm up to 16% on some builds! This helps out massively with my inverted yaws dropping like bricks :)

I'm running a raging droner with t motor f60 pro 4 1950kv. I left the stock 5.5 idle and put 20 in dynamic idle. I'm using configurator 10.7 RC1 and 4.2 RC1. It's definitely a great feature that improves flight performance. I'm a huge fan after trying it out. Thanks JB Edit. I ended up getting much better results doing proper math. It's definitely something that needs to be followed to a T for optimal results

My brain is freezing... 😂 But a the third or sixth view Il will learn something for sure 👌

Right on the spot! It was a topic with a friend while checking his configuration done by someone and his idle was set to 2. I was surprised to see such low value and asked if the person who set it knows what he was doing... Now the idle value has more clearer meaning to me, definetrly learned a big thing today. Instantly checked one of my quad and idle_min_rpm is set to 0 as default. As I understood in order to activate the dymanic idle, We have to put some value, right. I know it may seen a dumm question, yet I just need the clarification. Thanks Boss!

Thanks Josh from Australia! This is why my heavy 7 inch 6S always flys so unpredictable 😁

I don't even have a quad yet but when I can afford a decent set up I will (hopefully) have a better idea as to what I'm doing thanks to your videos. Keep up the good work and beginners thank you.

I usually use a 6.5 to 8.5 min idle depending how new or old my motors are. Reason being I like heavy props and hate de-sinks, but inverted I fall like a brick🤣 This could help, and reckon this is worth a go for sure. Thanks...

Josh this vid may be answer to my dsync I had. I check mine and idle min rpm was on default 0. Definitely will give this a try to as I get it rebuilt! Thank you

I always have the problem with yaw washouts when doing building dives with my Mobula7 and I found out that raising the idle to about 15%, where the quad is just about to lift off by it self, helps with the yaw washouts. I just recently got into dynamic idle but I'm still testing. (Yea, I'm commenting on a 4 year old Video)

Thanks Josh! I would have loved to see a before and after but I appreciate the video none the less!

Hey man, just wanted to say I enjoy your content as someone who is looking to get into drones!

So why would we ever want the pid controller to have access to the min_idle. If the quad flies so much better with higher percentage and if response times are slower when coming out of that super low rpm then aren't you recommending everyone runs higher idle and to not run min_idle? In what scenario would the PID controller getting to use min_idle actually be beneficial?

Thanks a lot no one is talking about this, excellent explanation.

Always enjoy watching your vids, always learning something new , question - will this work on smaller quads for example say a tiny whoop , tiny 7 , quads with brushed motors ? keep well brother and keep teaching us...

Im a freestyle pilot and usualy up my idle speed a bit more than default. I found it helps on propwash. Thanks for the explanation... going to try in the nexr flight.

So to just distill it slightly further.it helps your quad rotate around the center axis properly(or better than normal),rather than just lift one side of the quad to rotate.its the best we can do with the design of quads at present.ideally you would have a second motor&prop on each arm opposite mounted to the motor on top of the arm.so as one side spins up,the motor on the opposite arm facing down,would pull down.therefor having an equal push to pull&properly pushing the quad around its center point.but then youd pay a weight penalty&drag.so this dynamic idle&air mode etc. Is doing the best it can with the hard/&software configuration.theres been many incremental benefits added to bflight over the years.many of which we might have thought at the time were just adding complexity.which we now consider the norm&wouldn't be without.im just wondering when/if these incremental tweaks are gonna result in diminishing returns.although I do agree with this one as d syncs & motors being able to respond and spool up quicker from a certain point of idle.is allowing for spool up lag&the lag that the pid controller/rc system as a whole introduces to be partially negated.

Nicely said Bardwell!

I have MOTOR_STOP enabled and airmode controlled by a switch. If I during flight switch airmode off and lower the throttle to 0% the motors stop but they never stall, as soon as I increase the throttle all the motors start spinning again.

small correction: For BLDC's you shouldn't lose torque at lower speeds, torque is dependent entirely on magnetic flux in the core, which is governed by current. The motor certainly cannot _maintain_ high torque at low speed because inadequate cooling. I suspect this is more of a fundamental problem with sensorless control of said motors. desync happens because the ESC losses track of where the rotor is relative to the stator and the motor losses all torque.

This is the shiz you are good at. Freaking love it. Keep deep diving into this stuff.

Um at around 5:00 can it really spin around the center of mass? The pivot point should be somewhere between the right motor and the center of mass if not on the right motor imho, just because the right motor won't reverse thrust.

Thank u for teaching in to this. Hi from Latvia! Thank u for teach us more!

Hello Don't forget set transient_throttle_limit = 0 for idle Dynamic

So I got confused by the idle min section. You went through the exercise of getting the lowest possible rpm, (300) and then it seemed like you "winged it" and put in 1200 in the CLI. Do we use 4x the number we come up with?

These are the videos I love

Little spoiler, Joe Lucid and Thorsten Laux are, wait for it.... the same person. Lol. Not sure what the story is there, but both are very smart guys.

I need to check it myself too. But, on Mamba F405 MK2 stock min idle is 3.0 which is quite low already. Thanks for sharing Joshua!

10:42 is it posible that this minimum depends from battery voltage? lets say cel voltage is 4.2 and i set minimum idle, and batery drops to 3.9 can my motor stal from this?

So what is each motor has a different rpm in which it spins without hesitating while in the motors tab? For example, motor 1 is 350, 2 is 620, 3 is 900, and 4 is 900. Do I just take the motor with the highest rpm and use that?

No no no Completely overwhelmed and caught in the ceiling fan can we try this again. OK I just need to re watch this and then review the FB post then watch it again I guess

Can't find motor idle throttle value in betaflight's motors tab anymore

It looks like the holy grail to prevent desync but it isn't. Keep in mind that dshot_ilde_value provide a 100% reliable static thrust. While that idle_min_rpm rely on some sort of unrealiable pid loop that try to hit that min rpm but fails irl :) For my experience idle_min_rpm makes more harm than good because that min rpm suffers great oscillations in flight resulting in even more unpredictable stalls.

thnx for the explanation! maybe you could make more video's about features we do not use much, e.g. thrust linearization

Im quite a newbie to fpv, please guys tell me if im right about this. Ive revently learned to dive and i ve noticed that even with 0 throttle the quad goes forward quite a lot, it doesnt fall vertically but rather at 70° angle. Is this the right tutorial for me? Should i simply lower my throttle idle to that 2,5% that JB says is the freestyle minimum?

I’m sure I’ll THINK this has made a huge difference 😂 and that’s the important thing.

I need to pay this guy.

Ho Hooo you say good things. This piques my interest for I throw 6 in props and have acquired a taste for inverted ticks with hang time. To be honest this still is at the time of this comment my first acro drone the Butter Kwad. But reviewing other 5 inch freestyle drones with inverted yaw spins and such I'm realizing the 6 inch props arrest my drone faster then what I wish to achieve. Believe me I've tried. Don't even get me started on PID tuning. One problem after the other 😩 Will delve into this for sure. But I'm almost ready to throw in the towel on my Butter Kwad for what I'm trying to achieve. It hasn't quite turned out the multi tool I had envisioned. Never expected it to be a master of Cinema, Long Range and Free Style but something just don't add up. Pitch slow wobbles are really sticking in my craw too. P's over 120 now....I's at 60. maybe should just slam it at 250 P's with 30 D's FF off too

Yeahhhhh! Quad 66 needs more love in the community. He's kinda like Kebab was in the early days in his reviews and innovation

sweet video dude. this may fix the death roll issue I've been having on one kwad. on sharp rolls with a sharp ending it goes straight into death roll. I think it has to do with the motors i have on it. i was using the same type of motor on another quad that did it to me. but smashed a motor the first death spin and swapped brands. no issues since on that one. Thanks for the tips. might save me $60 in motors. 🤘🤘

Should I round up or down? Also, all the motors don't spin exactly the same rpm, so should I go with the fastest, slowest, or somewhere in the middle?

As someone who began flying way before airmode was a thing, back then all this would have been magic, increasing idle extremely high by today's standards was the only way to avoid what i called "the funk" in the sky! Since quads were not as powerful back then, such a high idle began to effect the responsiveness of the quad among other things.

I'm going to pose a question and see what your answer is. Why don't we use a sensor based esc in FPV? My background is heavy in surface and in racing in particular they use a sensor based esc. There is a cable that runs from the motor to the esc that tells the esc where the rotor is in its rotation allowing the esc to make more precise drive inputs giving the driver a better "feel". This is mainly for lower rpm and usually is turned off at higher rpm as the sensor actually hinders hi rpm performance. I see where this could be beneficial, especially for dynamic idle.

The way i understood, it had more to do with the throttle percentage being able to go below your normal idle percentage. So dynamic Idle will allow you to go below your normal idle percentage of lets say 5% throttle, in cases where reverse flow conditions are already providing torque on the motor (due to reverse flow on your props). So in your example for people who have high trottle percentages, should their min_rpm values correspond to the RPM they aim at to have a lot of response (which are high). The benefit there as i understand it, would be that the PID loop is allowed to lower throttle to 0% as long as the props keep spinning at the minimum desired speed. What am i missing here?

That's extremely interesting!!! I had never imagined that CaptainVani had 8% idle! Personally i had it down to 3% because 1) i find difficult to do inverted yaw spins because tends to fall faster 2) the quad takes forever to get down to the ground. I definitely learn something today. Question: Propellers pitch affect the idle ratio or dynamic idle?

My understanding of dynamic idle and how I have been setting it up has been a bit different. I wasn’t aware setting a min rpm would allow the FC to drop below the idle value. I think of the min rpm as a backup setting since. Like you showed when touching the motor with your hand, a throttle % doesn’t necessarily mean the motor is spinning. With props and backflow of air after a roll, that motor could possibly stop and desync. However, a min rpm is more accurate, so the FC could ramp up the throttle past your idle percent to match tour min rpm. (Dynamic) so I basically drop my idle value and tune the min rpm to feel the same as my idle value, then put the idle back. Now they both match, and I have a more accurate idle speed and desync protection. Have I been doing wrong? 😆

Another great video. Thank you JB.🏋️👍

Dammit Bardell, you're so smart, you're answering the question about deathrolls that I didn't go online and ask you about this weekend. The same quad, deathrolled twice lately, while descending into the next field (low throttle) where one motor on my (plus) frame was probably at idle. Without even checking, I bet my idle % is too low and you're a mind reading genius!

How is it you came to the number 12? What does too much look like?

Will idle_min be higher with a prop on?

Why doesn't dynamic idle replace air mode. If not why do you need both.

The feature I'm looking forward to trying in 4.2 is NFE race mode for micros.

hey joshua i have a pavo25 and when punch out and drop the throttle the motors start twitching when recover the altitude and latter have this same twitches in fly! any suggestion? you are help a lot over this fpv world!

I think this might have been the cause for my Mobula7 doing the death roll after coming down from a punch. As it's falling from a decent height with the throttle at idle I think the motors were probably stalling.

so tested mine. props on. got 600rpm no more twitch.. 800 to 1000 rpms i can add friction with finger on prop and still no stutter.. my idle is 4.5% (4,000rpms) 1207 6000Kv 2.5" (AUW between 160gr to as high as 345gr [Hero6]) So use the 3,200 80% value or try lower like 2,400?

Do one on thrust_linear!

Kinda random. But your audio sounds really good.

time stamp love it. you say its good i do it

When you took the base value of the stall speed of the motor by slowing it down to see the min value, you did this without a propeller on. If motor stall speed is a function of resistance like you said, you would want to have a propeller on during this to get the right base value...correct?

Betaflight 4.2.8 my default idle_min_rpm = 0. Been flying like this and it flies great so now im just confused after watching this video. What am i missing? Do you guys still fly with air mode?

Wouldn't you want a prop on the motor to know the minimum value it will spin at? Drag, friction, load... all that? Not that I'm suggesting someone have their props on when the quad is on the bench, but maybe adjust this outside with a laptop?

LOVE THAT T-SHIRT!!! Thanks for this post!! I learned something today!!!!

Thanks JB great video 👍 super informative 👍 👍

I noticed another not well known thing - you don't have to change arm angle to 180 anymore in order to use turtle mode, because turtle mode overrides it and allows to arm at any angle even if your max arm angle is set to something like 30, it does not apply to turtle mode. I believe even Joshua himself does not know this, because in all beginner videos he still tell to change arm angle to 180. I think it's better to leave arm angle to some normal value to have another failsafe to unwanted arming.

Has anyone used this tune on a Mobula7?.... Does this require Bi-directional Dshot to work?... I have switched over to JESC 48khz which I believe supports Bi-directional Dshot... However the Project Mockingbird Mockula7 tune that I’m using flys really well without Bi-directional Dshot / does not use rpm filters... I’m hesitant to turn that on as I’m uncertain if it will mess with my tune... any advice would be appreciated...

So wouldn't this be equal to the old finalglideaus and Mr Steele trick of using an idle up switch? I know Mr Steele didn't like airmode. But he'd use idle up to get a more responsive feel but not as prone to windup as airmode. I'm fairly certain that those guys also used motor stop for landing instead of disarm so the purpose of idle up wasn't just for response but also as motor stall prevention. I don't see this as a game changer as much as making people aware of some part of the flight dynamics for quadcopter. But I think not enough is said for thrust linear or atleast proper tuning of tpa for those not wanting to try something new. There is also a feature that adds throttle with tilt for level flight mode which is great for whoops.

I'm so confused with the Idle Value. On Github I read this: You may arm with the Tx in the motors tab (after setting the enable switch) to check that the idle RPM in real world is about the same as it is when running directly from the motors tab slider. You may notice that noise from the motors will cause some variability, but the RPM numbers should be about the same. No on my quad this does not match, i'm running 8% Dshot idle value working great. When I compare, motor switch in BF or Arm, the values are much different. BF switch: 2300rpm 23-20%(-4.6) = 18? TX Arm: 3400rpm 34-20%(-6.8)= 27? And later read if you have already setup the Dshot idle value you can just take -20% from that value?? :S Wutt how? Well since there is not a clear reference, rpm idle of 18 or 27 ok? or very high

Always learning from you Joshua. Just a clarification, in BF motor control do you consider the motor stalled when it stops rotating or when it starts to stutter? Yes, I'll watch the video again.

i have just checked my idle_min_rpm and its set to 0 by default. i have just set it to 12. im getting new motors delivered tomorrow so ill check what the min idle is then

does this mean I can turn air mode off

how do you download Betaflight onto you computer ?

Holy shit! A new shirt!

Does propwash have anything to do with idel percentage? Like can increasing ideal percentage lower propwash or fix it?

Probably up there with rc_smoothing_derivative_hz. Never seen anything about that out there for Crossfire.

I struggled with Dynamic Idle feature and burned more than 100 battery packs for test. I conclude +1-2% idle up is more stable than with this feature. Obviously, this feauture are designed if all 4 motors are equally good condition. but most of case we have not such a ideal condition except new quad and such a unbalanced motors situation we need the feature like a Dinamic idle..... When all motors are not equally good, this feature dive quad crazy suddenly while we do manoeuvre.. (BF4.2) i hoep somebody point me I am wrong.

And the default is set to 0 so what does that mean? How can 10 be too low but it should fly just fine on 0?

Thank you JB, On top of that, what is the behavior if you change value in BLheli like Throttle Min into a lower or upper value than the default in ESC firmware configuration ?

This is why I afilliate you always jb ....thanks ;)

I will have to disagree with a few things josh, Since blh_s came out, the idle speed could be set much lower than zero trust (ZT) and not have desyncs, I personally dont think there is a reason to go below ZT, all it does is increase response time and lower stability, witch is no good. So going lower than ZT (my idle setting) is not going to help anything. My knife edge (KE) test for correct idle speed. Hover in front of you with zero wind, launch 45 degrees up and straight away from you, chop thro and KE, the quad should go straight, to high rpm and the quad will curve from it making thrust, if curving, lower to make quad go straight. This will give ZT and best response time. Any lower and hurts response time, any higher and hurts inverted hang time. If you watch a roll on a quad from hover, it does not rotate around CG, watch my how low can you roll video (parody of the dji how high can you go guys). ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-uku7cEiqVIo.html "IF" Vanover is at 9%, then he does not like inverted hang time. I fly with 1950 rates, this also makes it much easier to desync from reverse airflow than the slow 1200 rates lots use. Thanks for the video.

i try to set the idle rpm min from cli but it wont saved after restart the value still zero ? anyone ? thanks in advance

Couldn’t pass this one ☝️ up. Thanks for the info JB 👍

Hi, Joshua After watching this video, I set my quad in CLI ”idle_min_rom = 12”. But it causes my quad after a fast flip bounce back. No matter how I increase the P and D term. After reviewing the BlackBox, it seems like motors desync. So I change the idle_min_rpm = 25. Then it almost the same with the motor idle throttle value. And the situation remains the same. When I change the setting ”idle_min_rpm = 0”. Everything back normal. I question is, could it my ESC or motor’s problem or something wrong with my setting?

I was trying to explain this the other day lol 😂 fantastic squire 👏🏼

My betaflight doesnt show RPMs on my motor tab - Do I need special features for that? I have a MAMBA F405 FC

Thank you for the briefing, Joshua! Have you gathered any feedback/opinion from Captain V.? Also, what is/are the parameters that cause the idle value to vary between the two endpoint settings? For example, if idle is only adjusted downward in response to differential prop rate (e.g., rolls or flips), then inverted hang time would still be lost if we raise our dshot_idle_value, right?

wouldnt rpm be higher with prop

I'm learning something today 👍