Vortex Ring State and your DJI Phantom...and how to avoid it!

[@FlyingCamau]

Thanks Grant, great explanation, I am a helicopter pilot and your explanation about VRS was very accurate. One extra that could help getting out of the VRS is to actually lower the throttle, with a forward attitude movement. That should help reduce the "dirty/turbulent" air even more.

[@GrantJohnstonVideos]

+FlyingCam.au Good advice thanks. Cheers

[@mw01720]

On real helicopters you can apply full left stick and full power to catch the updraft of the turbulent air.

[@gnbassett]

This post solves a lot of mysteries for me. My DJI dropped hard from about 50 feet while I gave it full throttle. Then I puzzled for a long time what had happened? Battery was good, modes were correct on the controller. Without an explanation, it has made me timid to fly it over any terrain where I would be unable to retrieve it. The thought of losing control over water or heavy woods is terrifying: just say good-by to a thousand dollars of equipment. I've never flown in a helicopter and I am unaware of the vagaries of helicopter flight. But I am a fixed wing pilot and I believe I have a good understanding of aerodynamics. But I never would have guessed what seems so obvious now. Many thanks.

[@GrantJohnstonVideos]

Glad it helped, I just about always descend now whilst moving forward or backwards and have never experienced it again. Cheers

[@ratherbflyin3301]

I'm a heli CFI, if you're interested in more knowledge. VRS sets up when you have a V/S of greater than 300 ft/min descent with an A/S below about 16-24 KIAS (Effective Translational Lift A/S), causing you to descend into your own vorticies. Above that A/S, it is not physically possible to get into VRS, no matter the V/S. Once in it, collective increase only increases the descent rate. In a standard heli, it's a very similar recovery to an airplane stall, if you remember those :-). Generally, power/weight ratios of the smaller RC helicopters allows the heli to power out of the VRS, though it doesn't seem to be the case with multirotors. Interestingly, real-life multirotors (e.g.: Chinooks) do a different technique to get out of VRS. Instead of pitching forward, they have to cyclic roll to one side or another. If they tried to pitch forward, the rear rotor would only increase pitch and accelerate VRS. There's a few techniques that you can use to get out of it, all depending on the type and setup of the helicopter. They all seem to focus on getting out of the "dirty" air (vorticies). Tried and true for most applications: Pitch forward, gain airspeed, and THEN add power to regain altitude.

[@dcnasoni]

Just happened to me... wobbled and I backed off power.. seconds it hit the ground! I found your video.. I'll know what to do in the future! Thanks for the info!!!

[@BIGDRONEFLYER77RC]

It just happened to me last week. Just glad it was a little quadcopter. but still sad I didn't learn about VRS first.thanks for the video.

[@robertburch47]

Thanks so much for the info on this. I crashed my P3S last weekend. Started the wobble when I was coming down for a landing. I now know how to avoid this and be able to recover if it does happen again. Thumbs up and subscribed.

[@LakeHartwellSimon]

I have had 2 crashes and thought it was because I messed up the aerodynamics by adding extended landing gear and installing graphite props. But in both crashes, I was doing a fairly rapid descent straight down, so this explains my pilot error.

[@GrantJohnstonVideos]

I also had Carbon props on in this instance so unsure whether they're more susceptible to this type of incident?

[@LakeHartwellSimon]

GrantJohnston Grant, I couldn't tell you if carbon props are more susceptible to VRS. I failed to say that I also installed the iOSD Mark II. This is also my second Phantom II. The first had the Zenmuse 3d-2d gimbal, Mini-iOSD as well as an Immersible 600mw video transmitter. Didn't have a VSR incident with that setup. However, I screwed up a takeoff from my boat and put the first Phantom in the water. So I got the second Phantom and decided to do all these upgrades....extended landing gear, iOSD Mark II and of course, still needed the Immersion 600 mw video transmitter. Oh, and of course, I needed to add camo skin to make it look "tactical". So my weight is higher on the second Phantom than the first.

[@thegadgetrulez]

This happened to me from 238ft with GPS hold. Started VRS and shattered on concrete. I did exactly the same thing, applying full power and didn't think of changing direction. I have been experiencing this for years and usually it is a small quad, and no damage is done. It was catistrofic to my CX20. Thankfully the frame is only $25. Everything still works after applying a bit of solder. :) Still waiting for body from gearbest.

[@GrantJohnstonVideos]

+Josh Hymer Thats a bummer. I've got a DJI Inspire and it hasn't happened to me again .. thankfully, but I'm also careful when descending now from the lesson learn't!

[@injusticeanywherethreatens4810]

I do not even fly a helicopter, military or the recreational kind, and I found your video extremely informative. However a visual diagram of the effect would help very much.

[@knoxieman]

My Cx20 has been doing this lately and I couldnt figure what it was, I also dropped from about 20 feet in to a paddock, snapped a couple of props and broke the prop guards which I am not going to bother with from now on. Thanks for this Grant I am going to practice the techniques to get out of trouble and also take your tips about vertical descents and try and avoid doing them.

[@DronesManawatu]

Hi grant, finally found a "kiwi" youtube. Your advise was excellent, as I have only just started out with flying phantoms. I had exactly the same issue, I upgraded the props, went into this wobble effect, and then crashed from a height. Thanks to you, I know now what the problem was. Cheers

[@GrantJohnstonVideos]

Glad to hear it was useful, that problem is a hard one to replicate, I've tried to get the phantom to do it again in a safe area with the carbon blades but couldn't. I'm also a lot more careful now when descending and will generally keep the quadcopter moving forwards or backwards when descending and spiral my way back down.

[@anzaeria]

Very informative video. I had previously heard about vrs occurring during a descent. Though someone claims that the same thing happened to him during a stationary hover. My Bugs 3 Pro recently fell out of the sky but it was not descending at the time. It had only been up in the air for about one or two minutes on a fully charged battery. This other guys reckons it may be due to vrs but I'm skeptical. Looks more like it lost power for some reason. It flipped over and fell like a rock. There was no payload attached.

[@BoundANDDetermined88]

Mr. Johnston, excellent video and explanation of the Vortex Ring State. Prior to today, I had never heard the term. Don't fly helicopters, and prefer to stay out of them as much as possible. Not knowing or knowing about the phenomenon, it seems when experiencing or witnessing the rapid descent, the natural thing is to apply "More Power" to reverse the condition. Recently (Yesterday) I purchased the Litchi drone app as an alternative to the DJI Go app. No problems with the Go app other than getting it to work with more than one IOS device in the house. I was planning on trying it out today after work, when I saw a post about a Phantom rocking a bit, then flipping over, and crashing to earth. The implication was that it was the app that caused the crash. This caused me some hesitation in wanting to try the new app. But based on this video, and some research, i don't know how the app would have caused the initial rocking and then an inverted descent & crash. All this aside, thanks for the detailed explanation of VRS and the correct corrective action to take. I feel the need to practice coming out of this possible situation and no more vertical descents unless absolutely necessary. Thanks!

[@GrantJohnstonVideos]

+John Ferguson Glad to hear it was useful. I just read an article online yesterday about a drone falling on a women's head in Canada and the operator not knowing what happened, I wonder if it was just this? Cheers

[@NJ-Tech]

great "point in case' there, Grant and well explained. I can tell you it's no more fun doing it in a real helicopter :) there is an area where slow airspeed and fast rate of decent meet that's called 'Dead man's curve' within which you'll experience this phenomenon (no guesses in why its named so) Always good to note the wind direction, especially on landing and if you want to descend fast, just keep your airspeed up. That is 'airspeed' and not 'ground speed' so we correctly account for wind. Cheers!

[@GrantJohnstonVideos]

Yeah I've spent a bit of time in real helicopters for work and its another one of those 'things' that plays on your mind sometimes! I just about always descend my Phantom now in a forward circular pattern and so far haven't had a problem with the Vortex Ring State. Cheers

[@ratherbflyin3301]

Neil, Fellow heli pilot here! I think the Dead Man's Curve you're referring to is mentioned on H/V diagrams, where poor combinations of airspeed and/or altitude don't allow for a safe autorotation if the engine should fail (the curved, "shaded area" of H/V diagrams). Noting wind direction is one of the hardest things to do, though!! Time and time again, I'm called out on not remembering where the wind is coming from, and I have actually gotten into VRS by foolishly doing S-turns with a crosswind on short final. Bad move! I've only recently learned that you can remember wind direction by checking it prior to takeoff, and then referencing the sun (we only fly for an hour or two, so the sun remains relatively stationary in the sky). Fly safe!

[@Sn1p0187]

Grant Johnston Yeah great tip!

[@primeguides]

Very useful info. I had the same problem in Malta and the quad came down in the middle of the main water park (not good) Good to know its a recoverable situation. Thanks

[@GrantJohnstonVideos]

Worldwide Photography I bet that was exciting!

[@wifiwaves]

Great video, Grant. You explain it very well.

[@denodan]

That is why in gps it's slow to come down to avoid this issue. You can come straight down if you wish, but unless tour moving forward while depending or going in a circle, your decent must be slow. Gps mode slows your decent.

[@benshamblin4407]

Thanks mate! Well thought-out video, good explanation, no bs.

[@trickysyoutube]

this explains it perfectly also... just lost mine in the drink ...Quadcopter "Wobble of Death": VRS Recovery and Avoidance

[@quadshotaerialphotography7423]

That is a great video. Very clear, and is explained very well. Thank you very much.

[@GrantJohnstonVideos]

+Quadshot Aerial Photography Cheers

[@Trainboy64]

Very good explanation.

[@alvaroreyes8110]

Just wondering if at high altitudes the vortex ring is constant I have a ominus dromida that 80% of the flights ends in vortex rings

[@tomastelensky-vlog8723]

Canon 70D is a good camera but the video seems a bit blurry. Why is that?

[@timmcgregor6732]

I just lost mine in the saltwater bay in San Diego for the very same reason you just described. Full throttle did nothing to help. Thanks for the information.

[@tattooedredheadx]

+Tim McGregor Sorry for your loss.

[@GrantJohnstonVideos]

+Tim McGregor Ouch...sorry to hear that.

[@timmcgregor6732]

+Kory White It happened sooo fast and it was a sick feeling to see it go down. There was a small cliff and I didn't know it had gone in the water until I looked over and saw it. Oh well! Expensive lesson.

[@timmcgregor6732]

+Grant Johnston I've watched yours and others on VRS videos and will definitely try to fly out next time and no increase in throttle. I'm not even sure if I had enough time to react. Next time I will make sure use directional flying to reduce altitude instead of guessing on straight down descending speed. Thanks for the great video!!

[@BasementEngineer]

+Tim McGregor D'oh, those puppies are pricey... VRS (settling with power) is to be avoided with RC models and full-sized helicopters alike. You're descending into your own downward-moving air and full power and lift won't prevent the descent. To get out, quickly fly in any direction.

[@dariusz879]

very helpful video with great advise, thanks.

[@motokid032]

And the heavier the payload, the easier it is to get into VRS.

[@miaoo1016]

DCS prepared me for this!!

[@aerchov]

Grant, DJI had a firmware update to the Phantom line a few months ago, around spring time, in which they've restricted the descent speed to 2 meters per second to prevent this exact issue. Did you have the latest firmware when this fall occurred, or were you flying with the old version and descending faster than 2m/sec?

[@GrantJohnstonVideos]

Hi - No my firmware was and is up to date and what made it more confusing was that I was only just starting to descend so was descending at a very low rate. I still think it was more to do with the tail wind which was a bit gusty at the time.

[@computerman4321]

And I thought VRS only affected huge aircraft like helicopters. Thankfully my drone survived but it's time to practice throttle control. I guess it's not as big a deal for small racing drones as it is for a larger drone.

[@sothathappened]

Thank you very much for the explanation.

[@GrantJohnstonVideos]

+sothathappened Cheers

[@Perryjw1]

Very informative, thanks!

[@plippplipp]

Hi Grant. I experienced this a couple of times a last summer. Since that I always use the white DJI original props. I dont trust my reseller who tries to sell these black composite props to me any more. Any thoughts about expensive composite props? And, have you tried to change the motor angle? With bricks of different thickness? Like all motors pointing out or all pointing to the center above the quad?

[@BasementEngineer]

+Jan Holmström That might be an idea for multirotors, 'aim' the motor shafts inward to converge at a point above the drone so that the downward airflows escape sideways, it might make SWP less likely to occur. It will also require more power to fly, giving reduced payload capacity and shorter flight times. It may also cause handling issues.

[@GrantJohnstonVideos]

+Jan Holmström Hi - Yes I didn't trust my carbon props and stuck with the original plastic ones. Didn't try changing the motor angles and would probably be beyond my level of mechanical competence!

[@plippplipp]

+Jan Holmström Bricks? Sorry, I forgot this is english. Washers!

[@dynamodelimited617]

Good advice, thanks.

[@camsmith1787]

What gimbal do you have on this Quadcopter?

[@GrantJohnstonVideos]

Cam Smith H3-3D gimbal

[@dronevideoproductionsinter7356]

Useful info. thanks..

[@SpicyCiorba]

does anyone else feels lucky after watching this?

[@bud01king]

happens to me today and guess what I did applied power lol and your right didn't help

[@primeguides]

Landed close to a cafe and then took off sideways, not a nice experience

[@narmadaskinclinic6750]

Preventing vrs is very natural skill but known to only those pilots who whave flown real quads and not these cheater gps quads because of obvious reasons

[@ephotosaver]

Thanks for the information