I second IchHab and COPaul, I think the cause was descending through your prop wash. Your normal rate of descent may usually be fine, but even a slight updraft would effectively increase that rate and likely lead to the instability you saw. Trying to regain control should include forward (or other lateral movement) to get the copter out of the disturbed air of the prop wash.
It's not battery or the FC mouth function. It's vortex ring state(VRS). What VRS is, is a ring of air when you descend being pushed down by the props descending then they go through the prop wash, making you have this problem. Your at high altitude in castle rock, CO. I live in CO so I've had this happen to me. It happens at higher altitudes because of the thin air. There's not many ways to fix it. When you notice it start doing this don't go up in throttle because it will make it worse. What you do is move side to side or front and back to keep the prop wash out of the blades.
Thanks for posting. All of us have seen it happen. It cost me a camera on my P2V+ and that wasn't cheap. Don't you wish you could deploy airbags when that happens? It is a helpless feeling. Cheers and good flying.
I thought about airbags, but to fly all the time with that added weight, it cuts down on you flight time. What I thought about was hooking my hexacopter to a weather balloon that doesn't totally lift the hexacopter but lifts 80% of the weight ... Imagine the extra flight time you would get ... plus if something fails, the copter will gently land... :)
I try to keep my descent at no more than 2.1 m/s. When it crashed I saw on my ground station a descent rate of 4 to 5m/s. Scary to see that on your screen!
I run a 450 quad with naza and will have the same problem coming straight down when in GPS mode. Although not as violent as you had. I don’t blame the GPS or naza as much as the aircraft and controller not understanding what is happening. My does it more with very low throttle coming strait down. It won’t do it if you have some forward movement, try to circle when you are landing.
Look for videos on "Death Wobble". Lots of theories on Vortex Ring State which happens to full scale copters, but some question as to whether it is possible in a multi rotor due to multiple counter rotating props. I have been struggling with this for a while and the recipe includes a heavily loaded copter, low battery power, and turbulence. The turbulence can be caused by wind, by changing direction too quickly or by descending into you own prop wash (which is not true vortex ring state). It helps to descend while moving horizontally. You can sometimes recover from a death wobble by giving it full throttle and full forward for a few seconds. Good Luck.
a sugestion, dont land with GPS mode....... land with altitude hold or with full manual mode and dont use t plugs, use xt60 plugs...... my 2 escs got short out and went broken with t plugs, i suspected that the t plug got too loose and ends with shorts if you using NAZA, just recalibrate regularly, before or each flight
Thank you for the recalibrating tip ... that is something that someone else advised me to do recently every time I fly in a different geographical area. This other person also suggested that I do an IMU calibration regularly - something I have done only when I first put my hexa together.
Hi guys, i had same crash with Naza on Tarot 690s. during the flight if i move it to right left or right, it was shaking a bit always. When i was bringing it down, it started wobbling heavily and ultimately crashed. What could be the reason pls let me know.
Thank you .. Arris CM2000 one of the first brushless gimbals out there at an affordable price. There are probably much better ones out there at this point.
Thanx for replying also what gains are u using because I installed a gopro gimbal an I'm using two 2200.parallel batterys I is flying good but when I yaw.to any direction stead rotate it makes like big circulation it doesn't rotate at the same spot any idea I got 145 on my settings an a naza v2
In my case it was the fake Dean's connectors I was using. They could not handled the higher currents that flow thru the connectors once the voltage in the battery drops. P=V*I (power = voltage * current). The power requirement of your multi rotor is a function of battery voltage and current. We know that the battery voltage drops, therefore, in order to maintain the same power requirement the current would have to go up. Since this happened at the end of my flight (batteries almost drained) ...that was the only plausible explanation that I was able to come up for my crash. I've flown many other flights since with XT60 connectors and never had that problem again. Were you at the beginning or the end of your flight? What was the battery voltage when the crash occurred?
Hmm. I dont know when it happens. The first minutes i have no problem. The problem comes after the half of the flight capacity. I am using Lipo 3s 5000mah and the connectors HXT 4mm to XT60. Hmm shouldnt be the same problem that you have had.
Very interesting. I run a custom Octo and had a similar crash-- the builder suspected low voltage. But the octo made a horrible squealing sound at moment of trouble. I upgraded the DJI WooKong M (2.0) and had no trouble until the other day-- at Dealey Plaza in Dallas no less. I started the props, felt something was wrong and killed it on the controller-- but it just started hopping and then took off. I tried the fail switch and finally turned off controller and it seemed to return to home. My hands shook for 30 minutes. (RU-vid search "octo gone wild"). ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-AEmzxYBXjgg.html If any one can figure out what happened, I'd be grateful.
