Your VRS Escape Plan
- Thread starter damoncooper
- Start date
Nice lateral escape! Although you did seem to have forward movement at time of VRS onset. Tail wind possibly a factor? Which software version?
Excellent post. My Phantom dropped out of the sky yesterday and I had a minor heart attach. Here's what happened:
- Absolutely still and calm, altitude ~ 4,000 feet in a valley
- Noon, temperature ~ 25 degrees Celsius
After a couple of minutes of eventless flight, I had brought the Phantom (2 Vision +) closeby and it was at approximately 50 feet above me. I was descending (slowly) - vertically with no horizontal stick - when all of a sudden the Phantom started wobbling and dropping uncontrollably. I only had a few seconds as she was just above a couple of trees, but I tried applying hard elevation (left stick) but that didn't work. Within seconds she was behind the trees and out of sight. End result: broken prop guard, scuffed body, props seem okay - no visible damage to the camera.
Questions:
1. Do you think this was classic VRS?
2. Should I change the props? They seem scuffed but otherwise okay. (The prop guard is broken, I have to change it for sure)
I'm a fairly new pilot with around 10 successful flights so far. At the moment my heart is in my mouth and I am scared to send her far out (or fly her at all).
Suggestions? Experiences?
Cheers
- Absolutely still and calm, altitude ~ 4,000 feet in a valley
- Noon, temperature ~ 25 degrees Celsius
After a couple of minutes of eventless flight, I had brought the Phantom (2 Vision +) closeby and it was at approximately 50 feet above me. I was descending (slowly) - vertically with no horizontal stick - when all of a sudden the Phantom started wobbling and dropping uncontrollably. I only had a few seconds as she was just above a couple of trees, but I tried applying hard elevation (left stick) but that didn't work. Within seconds she was behind the trees and out of sight. End result: broken prop guard, scuffed body, props seem okay - no visible damage to the camera.
Questions:
1. Do you think this was classic VRS?
2. Should I change the props? They seem scuffed but otherwise okay. (The prop guard is broken, I have to change it for sure)
I'm a fairly new pilot with around 10 successful flights so far. At the moment my heart is in my mouth and I am scared to send her far out (or fly her at all).
Suggestions? Experiences?
Cheers
monkey-wrench said:
The "wobble" sounds like classic VRS, but first a few questions:
- what version of firmware are you on? V3.0.4 and above limit vertical descent speed to 2m/s.
- do you recall what your descent rate was?
I'd do a full inspection, firmware update and calibration before sending it back up. Open it up and look for loose soldering points and motor mounts in particular.
I was flying out front of my house with prop guards. Flying slow almost hovering it started wobblinlg and jerking around. I though it was going to fly away. I flipped to atti , and got some control and landed. Took off the guards and all was fine.
I normally don't fly with them. But I have a bunch of trees around.
This isn't my first quad been flying dji since they came out. I had just updated the firmware did all the calibrations.
Could this be vsr ?
I normally don't fly with them. But I have a bunch of trees around.
This isn't my first quad been flying dji since they came out. I had just updated the firmware did all the calibrations.
Could this be vsr ?
Mori55 said:
Not sure but like I said in the top level post above, there have been many reports of users with prop guards and heavily laden quads encountering VRS.
There seems to be general agreement that using prop guards appears to increase the chances of invoking VRS.
Great post! I think it's sticky worthy (if it hasn't been yet).
I usually check wind speed all the time (via Weather Underground app/site) before flying. My last flight was next to a beach with 13 MPH winds (gusts up to 18 according to the app) and it flew smoothly and held it's spot. I think if I had prop guards it would've been another story. Didn't know that yaw could cause VRS too.
I'm actually considering investing on a portable wind meter so hopefully I could get more accurate wind speeds. I'm really on the fence about it though, because unless you've been living under a rock the whole time.. you would know what bad wind speeds look like (you should see me look at trees often).
I usually check wind speed all the time (via Weather Underground app/site) before flying. My last flight was next to a beach with 13 MPH winds (gusts up to 18 according to the app) and it flew smoothly and held it's spot. I think if I had prop guards it would've been another story. Didn't know that yaw could cause VRS too.
I'm actually considering investing on a portable wind meter so hopefully I could get more accurate wind speeds. I'm really on the fence about it though, because unless you've been living under a rock the whole time.. you would know what bad wind speeds look like (you should see me look at trees often).
UrAwFuL said:
You can get basic handheld anemometers for well under £10/$17. Like you say, with experience you get to know if it's too windy, but I still use one because it prevents the temptation to "just fly a little bit anyway". I have a hard limit on ground wind speed (don't forget winds aloft will be much stronger) and if the little anemometer shows above that then it's much harder to kid yourself the wind is under whatever your personal limits are. It's also useful if you're flying in very open areas without anything to help your gauge wind strength. Unconsciously we can probably all sugar-coat things, especially if you've travelled a bit to get to a flying site or you're itching to go after a bit of a grounding, or wanting to test new mods, etc. It's good to have an objective measure to keep you on the right side. It's the old pilot adage of "better to be down here wishing you were up there than the other way around"!
damoncooper said:
- I'm flying with the stock firmware. I have no idea what it is - but thank you for bringing this up, I will check now.
- Descent rate was fairly gradual, with the left stick lightly pressed southwards. I'd hazard around 1 m/s.
I've done a full inspection. There is mud everywhere (it was pretty damp that day) - apart from that everything seems shipshape. I believe she hit a tree going down, so that could have cushioned the blow.
Great write-up! One thing I've noticed is that people tend to blame VRS for some crashes where it probably doesn't apply. I posted a FPV showing VRS at: https://www.youtube.com/watch?v=Nm_5a4xwdP4
I found a completely different phenomenon can cause wrecks at very high altitudes (in my case >14,000 ft.; I've never noticed it at lower altitudes like 10,000 ft.) Briefly, the air density at high altitude is, of course, significantly less dense at high altitude. The theory is that the copter has to work harder to stay aloft but also has less air to cool the motors. It appears that at some point the motors overheat and you will immediately lose lift, causing the copter to drop. I've posted a video on this phenomenon at: https://www.youtube.com/watch?v=WrWDCaBG4xk
Because the Phantom's almost fly themselves, this can catch you by surprise. You can be flying along normally, gaining a lot of confidence, when suddenly the copter will drop. It has nothing to do with descending; it can happen at any time.
I purchased a temperature gun that I plan to use to confirm the theory, collecting motor temperatures at lower altitude and at higher altitude. Unfortunately, we are having an unusual amount of rain in Colorado right now so my tests will have to wait a bit.
I found a completely different phenomenon can cause wrecks at very high altitudes (in my case >14,000 ft.; I've never noticed it at lower altitudes like 10,000 ft.) Briefly, the air density at high altitude is, of course, significantly less dense at high altitude. The theory is that the copter has to work harder to stay aloft but also has less air to cool the motors. It appears that at some point the motors overheat and you will immediately lose lift, causing the copter to drop. I've posted a video on this phenomenon at: https://www.youtube.com/watch?v=WrWDCaBG4xk
Because the Phantom's almost fly themselves, this can catch you by surprise. You can be flying along normally, gaining a lot of confidence, when suddenly the copter will drop. It has nothing to do with descending; it can happen at any time.
I purchased a temperature gun that I plan to use to confirm the theory, collecting motor temperatures at lower altitude and at higher altitude. Unfortunately, we are having an unusual amount of rain in Colorado right now so my tests will have to wait a bit.
Interesting and makes sense. I'd venture to guess that the new 9450 high-lift props might help at higher altitudes (as well as VRS).
monkey-wrench said:damoncooper said:
- I'm flying with the stock firmware. I have no idea what it is - but thank you for bringing this up, I will check now.
- Descent rate was fairly gradual, with the left stick lightly pressed southwards. I'd hazard around 1 m/s.
I've done a full inspection. There is mud everywhere (it was pretty damp that day) - apart from that everything seems shipshape. I believe she hit a tree going down, so that could have cushioned the blow.
If you are running < v3.0.4 there's a decent chance you were descending too quickly straight down. (3.0.4 limits descent to 2m/s for this reason).
Best plan: avoid VRS. I've personally adopted a "never straight down > 1.5 m/s" policy and try to always shed altitude while coming home using Home Lock and keeping horizontal speed at a good clip. It also looks very cool
damoncooper said:Best plan: avoid VRS. I've personally adopted a "never straight down > 1.5 m/s" policy and try to always shed altitude while coming home using Home Lock and keeping horizontal speed at a good clip. It also looks very cool
Yeah me too. It does look cool when its descending on a vector right towards you from wherever it is. A real crowd pleaser.
The only time I come straight down is from about 10-15 feet up when I am doing a ground landing, and I am coming down much less than the maximum descent speed for a nice soft landing.
Starting to see more folks scratching their heads at VRS symptoms. Just posting again to out it top of list in the hopes of saving someone a crash.
The 9450's are a great tool to have in your toolkit for sure.
Flew them for the first time today and for heavier loaded or high flying, need-to-get-down-fast missions they're great.
On sunny days or long missions I add a glass PolarPro ND filter and Garmin GPS tracker and the claim at least is they add 100g extra lifting capacity and I believe it.
Also helping steer clear of VRS is worth it.
Flew them for the first time today and for heavier loaded or high flying, need-to-get-down-fast missions they're great.
On sunny days or long missions I add a glass PolarPro ND filter and Garmin GPS tracker and the claim at least is they add 100g extra lifting capacity and I believe it.
Also helping steer clear of VRS is worth it.
damoncooper said:
New pilot here with a new-to-me DSLRPros V1.X, with up-to-date firmware running T2 with motors Cw/CCW threading, 9443 props and V2 guards (newbie time still), dual 2400mah batteries, an H3-2D, Flyshark 400mW TX and cloverleaf, and GoPro H3+ with clear lens cover. Yesterday afternoon I was testing different GoPro video rates and widths by flying straight up with the camera level with horizon, execute yaw pans, then point camera downwards and descend straght down. I did this at least 6X, swappping in fresh batteries after each test. I just this morning read about VRS and am realizing that explains the crazy turbulence I was seeing with heavy yaw during full rate descents in my first set of test flights. I was able to manage the VRS by reducing descent rate, countering the unstable yaw and adding in reverse/forward/reverse/forward pitch. Didn't think to switch to ATTI. That would make sense - it felt like I was fighting against GPS correction attempts in addition to the turbulent instability.
Now I think I have a handle on what was happening. I'm also really glad I've spent a fair amount of time flying the Phantom in full manual, and that mastering little Hubsan.
I'll order up a a set of 9450 props to see how the PHantom performs in comparison.
Thanks for the thread!
Good luck and glad it was helpful. I personally think a warning sheet about VRS should be included in every box. But that would put a damper on pilot error replacements
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