Good day to all! For the last two weeks I have been cursed with this problem. What happens is when I am flying after I have gone through all of my checks and safety procedures as if it were any normal flight. I will be flying for about 30 seconds when the Cinestar starts to yaw to the right and I am unable to correct it. I lose control of my rudder input and have to maneuver the craft the the ground as gently as possible, while the copter spins out of control. I have a video link for your viewing, unfortunately I do not have a GPX file for this flight because my sd card was still in the computer from when I forwarded the data to Quadrocopter. So far they have been unable to resolve the issue. I also took some photos of the boards to see if anything is out of the ordinary but everything looks normal. Before you ask, my copter is set up correctly. it is not an error on my part, so far.
Is it possible that one of your motor booms or motor mounts is loose? If you walk around the copter and twist each motor left and right, can you get them to move at all?
Jeremy was it previously flying ok? Can't tell from the photos with the FC board arrow if it is pointing at boom 1? Have you checked that the trims are centered on your TX for Yaw and have you run a stick calibration on the TX if you are using a Graupner? Easy to check on the monitor screen whether the yaw stick is actually centered. Lastly if it is yawing and those items are fine then you may have a motor that is not vertical.
@ Steve, the booms and motors are all secured. @Gary, All of my trim settings are at zero, my motors and booms are sitting where they should be, I have indicator's on each boom to align with the hub. I am not sure how to perform a stick calibration. I use the Mz-24. The strange part about is it will fly the way it was intended to and then all of a sudden it goes haywire and when I try to correct the yaw, my rudder does not respond. The problem is getting progressively worse. I live in NY, I took it to florida, Back to NY and after that I went to Vermont to film. It was in Vermont as I as flying and first noticed it drifting and losing control, but after a second or two of loss in rudder function it would regain focus and I could control the copter to a safe landing. FYI, The copter is near new with only 8 hours of flight time.
Jeremy, I have experienced this as well and it totaled one of my copters. I thought it was a firmware issue with the FC not talking to the I2C converter correctly that I was using. The copter flew great for 2 years on firmware 1.90j. I updated to 2.06 and had 5 good flights then the copter went in. However mine was a full on, someone walked over and held down the YAW stick and wouldn't let go, type of crash. Here is a video... Curious what you find out! Josh
That suck's, The copter acted just like that the flight before last, which is when I had my crash. The video I posted doesn't show the problem as well as i have witnessed it lol. Were you ever able to find an exact cause to the problem? I haven't done any firmware updates since i've owned my rig.
The wires on that are a bit of a mess that are causing tons of EMI and the lack of hot glue on the molex/SPI/10pin is a problem waiting to happen (they can/will vibrate loose). Try to bind all your motor control wires together and wind/braid them. As i learned with letting a SPI cable from FC to Nav slip under a capacitor it can cause untold issues. Also you can see higher amp draws on even motors due to interference with the NC if your wires are not wound/braided which COULD cause uncontrolled yaw due to high EMI. Also, what motors? Tiger 4012s? And what BL version? I see 1.02D on the board but have you updated that yet? What Gary said is one potential resolution (And I hope that is it), another I would hazzard is that you are having an I2c issue and possibly a bad molex cable/port on either the FC or BL. One of the recent hex combi boards I got had a bad Molex cable with it that had 100 ohms of resistance in one wire causing the signal to not cross to the BL for throttle, pitch and yaw.
Hello, I've seen unwanted yaw when "Compass Effect" is set above 0, the props aren't straight, zero payloads with wind when the motors are not spinning fast enough to effectively counter torque, and also when falling - also related to low torque control with very little throttle. 9-10 times it's mainly from my props not being straight. You would think it would be constant but it does start and stop during the flight. Cheers, Jeff
I wonder if there is a deeper problem behind that. I know of at least 3 copters with unexplained yaw issues. A Cinestar 8, Cinestar 8 HL with U5 and a Cyberquad. All three fly fine and then here and there suddenly yaw. Anything between 30 degrees to continuous spinning. They all fly fine and the after a couple of flights the problem happens not to be seen in the next couple of flights again..
A friends S800 evo was doing something similar a few weeks back before they replaced it with a MK HL hex. One motor would max out and cause the whole thing to yaw/spin. we found out later that the capacitors on the ESC's had swollen (which does not look present on this board on the top at least) from 3mm to 5.6mm causing varied current to flow into the motor causing the occasional yaw.
We will need to get GPX log files for a copter flight that shows this problem so we can dig deeper, I think. It sounds like either (a) motor decommutation or (b) ESC failure (transient or intermittent) could cause the problem. I've also seen it with a loose prop. Please do not ask me how I know about this.... Andy.
I'll have to wait until I am in front of the computer to tell you what version I have for firmware, 2.06 if I'm not mistaken. I flew for 14 minutes today without an incident. First flight I disconnected the nav/GPS, and my fpv downlink. No problems so I brought back each system individually and the copter continued to fly without a problem. Just to be clear, you are telling me to braid the motor wires that are coming right off the distribution board? Is there anything else you would recommend? My gpx files show higher than normal amp draw on motors 1,3,5 and 7. Aside from the lack of glue on my 10 pin and 6 pin connectors is there anything else you would recommend?
At f Hi Jeff, I was flying in manual both times when use occurred. At first I thought the yaw was due to a lack of throttle like you thought. But it is not. The yaw now occurs when increasing throttle. And to note all of my booms, props and motor are tight and level! In addition, my compass effect has set to zero, was at 64. After it was reset, I still encountered the problem. It's actually the flight in the video about
Motors 1, 3, 5, and 7, being all the odd numbered motors, should be spinning clockwise. Which means that they generate a counterclockwise torque. That tells you than one or more of the even numbered motors might not be absolutely vertical and is generating a clockwise rotation that motors 1, 3, 5 and 7 will work to overcome. Can you verify that the odd numbered motors are also running hotter than the even number motors? The temperature can act as a rough proxy for the amount of current being drawn so you should seem them being hotter. Can you post a GPX file so we can see what's going on, please? Andy.
Uncontrollable yaw will happen if your motors are nearing their lifting ability for the weight of the copter. Its worse in wind where they are working harder so it may happen at lower payloads in this situation. Basically the flight controller is trying to maintain attitude, altitude, and heading. At some point it doesn't have enough power available to maintain all.. yaw will be the first to go. You may experience swimming yaw where full input has some ability to slow down the rotation but control is very loose. Its most likely to happen in a hover or very slow flight and in windy conditions. One way I test is to fly without a payload and give momentary full yaw command while in a hover. If it stops immediately when the stick is released, all is good. Add weight, test again. At some point the copter won't be able to stop immediately. Much of the power is now being used to lift the copter with not much reserved for yaw. Remember to yaw, every other motor is increasing in power to torque the copter around. When you command a stop, opposite motors will need power to stop the yaw. Its all about how much power is available.
Good points, Brad. As you say, you need "headroom" in terms of spare power from the motors to control yaw rather than providing just vertical lift. Andy
I would also look carefully at each motor when you land, and if you can, measure its temperature. One thing that's not tracked in the GPX file (which you MUST get for any real results here) is motor temp. The ESC temp is measured, but that's only part of the story. If you have a marginal motor (bearing, bad wiring) that can cause this problem, but without corroboration of current levels per motor, it's going to be all but impossible to diagnose this. Higher than normal amp draws on motors 1, 3, 5 and 7 would indicate to me that one of those motors is possibly bad and the others are trying to compensate. If you have a spare motor, you could swap out each of those 4 motors and measure in flight for any significant change. If you post some GPX files you'll save yourself (and all of us) some time.
The BL firmware version is also very important. Hot glue that MOLEX as well on the GPS>NC and FC>BL. What I do is bring the wires together and heatshrink them 1" from the lead ends (bullet connector end), I Think QC zip ties them (same effect but you want them to be close as possible together so the lorentz effect is minimal as possible. The high amp draw can result from numerous things, EMI in the NC can cause that as well as all the things Steve listed. Try raising your GPS up one plastic standoff as well, also make sure none of your communication cables are running near a capacitor as that can cause the cables to get EMI as well, which can translate to issues in the NC and GPS.