Second Test Flight Second Crash, Need Help!

Hello folks,

I managed to get out into the field for the second test run with my y6 tonight, and once again it crashed.

This first crash I do believe was my own doing as the grass was to tall for lift off and also a prop not came off loosing a prop, although only fell from 1 metre approx, there seemed to be no damage.

Tonight I had a different issue, which may be a result of my first crash.

After my crash tonight (using a pre build wooden lift off platform) I had a similar crash where the front end seems to drop resulting in a instant roll not even half a metre off the ground.

I noticed something that caught my attention, the lower right prop did not seem to be spinning from sight with the same rotation force as the others. Perhaps a trick of the eye but uncertain.

Would this be a sign of a burnt out motor? How could i check to be certain?

(I never did any ESC programming as i could not manage to get pixhawk to boot in all at once esc program mode.)

Could this be the issue?

Throttle doesn't seem to have any effect until mid point, does this seem correct?

Finally there are no local dealers who sell APC 11/4.7 props (one shattered in second crash need a sf and only have a spf), would there be any efficient size replacements?

Would completely changing all 6 props to 10/4.5's work?

Motors & ESC's

-jDrones 850kv motor's + jDrones 20A ESC's

Thanks in Advance.

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    • That behavior of the motor is consistent with one leg of the motor not getting power.  That could be due to a bad motor, bad esc, or bad wiring.  I'm not sure if bad calibration could ever give you that result, but I think not.  The wiring is suspect due to the impacts and other physical stresses.  Next would be the motor.  Try putting a spare motor loosely on that ESC, or swap motor leads temporarily with another motor.  

    • Sounds good,

      I'll have to order a spare motor, and esc then give it a test cause all my wiring i soldered pretty extensively with shrink tubing holding the wired end to the connector and also on top to hold the connection between the connectors themselves but anything is possible so i'll definitely be checking that also thanks!

      Another motor on top made a slight clicking noise, could that be a sign that it is going also?

      Thanks for the help Haygood, always right on!

  • You willl need to calibrate your ESCs the manual way. I.e. plug the ESC control directly into the receiver throttle socket. Power on with throttle on the transmitter on full then set throttle to min immediately after you hear the tone. Power off and repeat for all motors. This method is detailed in the arducopter instructions if you dig around. I also found the "auto" calibrate method did not work at first. Once done hold the copter down and power up the motors in stabilize mode. This will tell you if you have a problem ESC or motor (warning; the blades are sharp at speed!). You can also test at low throttle by lifting the legs up one at a time and the opposite blades will compensate.

    Take off in stabilize mode - that way you have a fair idea what is going to happen. Essential at first to ensure copter is close to level as opposite blades compensating can be offputting. Yes, taking off relatively quickly is the preferable way initially. Remember in stabilize mode taking hands off the controls (ie. Centering them) will leave the copter stable and give you time to recover. Know where the Loiter and RTL switches are as they can be VERY useful early on. Good luck!

    • Unfortunately, the radio side of things is my weak point, so I'm not completely positive my switches are properly set up or even if they are at all with the turnigy 9xr? My intention for building the Y6 was never really to even use a radio my hopes was to use it mostly as an autonomous device for my graduates research thesis but I've spent all the time messing around with the radio with zero time using any autonomous features what so ever. It's been somewhat discouraging in trying to get it up and running but I try to stay optimistic that i'll happen sooner or later.

      I do agree 100% that the switches will key though and i'll without a doubt be looking into how to setup and properly use them!

      Esc's programming is top on my list of things to do today , so at the same time i'll try to establish if my motor is actually fried, since i'll be doing each esc manually.

      Thanks for the advice!

  • In Alt Hold mode, throttle won't have any effect until mid throttle, because anything below middle means "go down" and anything above middle means "go up".  In Stabilize, the throttle should be more proportional.  If it isn't, then you need to synchromize the ESC's.  This could well be your problem.

    When launching, briefly give it a lot of throttle to jerk it off of the ground suddenly.  This will free it from grass, mud, snow, or whatnot without incident, so long as you moderate the throttle as soon as it lifts off.  

    • I've been sticking in "Auto" mode mostly for now.

      I haven't been able to get any function using just ground control, running loiter, or any of the other functions in the small actions tab in apm planner, so my assumption was i either required to set a wave point planned flight for function or i need to take off with the radio in order to establish control.

      Would the from bottom motor be burnt out? it did spin to some extent, just seemed far less than all the others? It would spin perfectly manually, although seem to spin slightly easier than the others, as they had a slight more resistance with a prop on (hate spinning them without power but wanted to see if the crashed cause anything).

      I'm thinking it could be a few things....the first being esc 's need to be calibrated (the solution i'm guessing will work) and maybe also perhaps i did not properly calibrated my radio and its trying to roll or pitch unintentionally.

      Thanks for advice!... esc 's are on top of my list to try!     And also that is great news about snow, cause around here -35*C and snow is a constant battle each winter.

    • It took me a while to figure out how to get it lift off correctly. I did calibrate the ESC's, and for what it's worth, my Y6 DIY came with one bad motor, so it wasn't all my fault. Even after replacing the motor it still wanted to pull hard right roll. It took a while, but now it lifts nice and hovers in stab mode with no wind.

      I had the toilet bowl problem in RTL, Land mode didn't work right another time but fortunately no serious crashes. I think all if not close to all issues was operator error of one sort or another. These multicopters aren't perfect, but there's a lot to know before getting it off the ground and staying there without a mishap, then land without flipping over or worse.

      Did you set the frame type to Y6 (A or B depending on what you have) and use the 3DR default settings for frame type? Did you go through ALL the calibrations including radio calibration to make sure everything is set up correctly first? Is the CG good?

      I'm still a noob but have learned quickly to make sure the radio is setup properly so that it works in concert with Mission Planner (what I use). If you can't use the flight modes, then maybe the radio isn't programmed correctly.

      After I made sure I followed all instructions to a 'T' (some are not up to date so you have to do a bit of searching on some things), got the copter up and first adjusted the trims and saved to the FC, then zeroed the radio trims.

      Out of curiosity, what radio tx are you using?

    • Hello, 

      My setup is all built from the ground up, mostly all 3dr y6 parts with the exception of the motors and esc,s which programming would be a good idea i'm thinking.

      I'm setup to run the old style y6 so i'm guessing that means A? I ran through all calibrations as per the website and also per the manual it comes with, at first i had rail issues (turnigy 9xr with xjt module to frisky x8r which would refuse to work over standard sbus requiring me to use a ppm encoder). Took me a while to run the radio calibration but ppm encoder solved that.

      CG i thought was pretty good considering the bare minimum i have on the y6. no sensors yet or anything just hard mounted go pro on the under belly in front and 3s in mid with slightly in back.

      As for motors their all jDrones 850kv and esc 's are also jDrones 20A. They all seemed fine first flight but after the crash maybe i damaged one? find it hard to believe but i guess its possible as it didn't have the same power although it did spin. 

      As for ground, thats the only way i know how to arm the y6 is via ground control so I do get some connectivity, as well as my elevation, altitude, gps fix, lipo status and pitch ect... does change in data points in the primary flight display so I do get some communication i would only assume, thats why i thought perhaps its just lack of understanding how to actually use these modes , suchs is merely selecting loiter cause the y6 to take off and loiter autonomously? or does it first require manual intervention? Same with autonomous flights with wave points for instances of 3d mapping would I also have tp manual take off or could this be done autonomously?

      Thanks for your response and suggestions!

      I'll definitely have a look at radio calibrations again maybe their off.

    • Ha! I have a Frsky Taranis x9d as primary radio and x6r rx. Binding was easy and used SBus. However the left gimbal spring broke for Yaw so I had to send it back for repair/replacement.

      Well, I had a new 9XR sitting there so am using that now. I have Opentx in both radios (figured no sense in doubling the confusion). It took a while but today I finally got it up and running through Mission Planner. I also used Companion9x to test the radio settings.

      I had no problems using the 9XR with the x6r sbus; did not need ppm encoder. Odd your XJT module wouldn't cooperate. I have DJT module originally for use with a D8R-XP rx for another project.

      Ok, so here's my question: Are you sure your motors are set up correctly for Y6A and the frame type for it? Did you test the motors? I've heard that violent crashes on lift off can be from motors set up wrong or frame type loaded.  Why didn't you go with Y6B? Just wondering; I have no prior experience to draw from, but thought Y6B was the preferred method now.

      To double check my setup, I raised the prop speed to high idle, then move the Yaw/Pitch/Roll sticks to see if the copter tried to lean in the correct direction.

      I used Andoni's setup to understand the basics of programming the 9Xr with Opentx.

      Companion9x is your friend, but you can do it in the radio without it.

    • I tried to bind using sbus but had no success in getting the pixhawk to read the x8r as i could get direct motor control from the x8r without the puxhawk. 

      So I contacted 3dr about the issue and there response wasn't very reassuring n'or did it instil any form on confidence in them as the support person could not even confirm n'or deny wether or not sbus should work as they did not have the exact radio i'm using to run tests, but instead just affirmed my "hit or miss theory" about their hardware and its compatibility, ultimately basing their conclusion on the fact that its "open source", which is fine, but there probably should be better understanding of the capabilities of ones own hardware. (I've read many people have had success with this radio setup and ones highly similar also)

      I'm currently using the factory supplied firmware in the 9xr as I have no idea where to even begin to switch to opentx and i could only assume i would need some form of cable to make the switch? (sorry still in the learning process and radios are my downfall)

      When I had began to build my Y6 back in January (we get pretty hostile winters sometimes so theres a few downtime months each year) I don't think the "B" version was out yet and also i had all the props for the "A" version 10/4.7 tops 11/4.7 bottoms, where isn't B only 10/4.7s both top and bottom? As for location of motors i did assemble is pretty thoroughly to make sure each motors are in the proper location and that the two wires in the wiring oppose each other for the CW vs CCW motors, (I did get lift off first flight attempt last week by applying a fair amount of throttle quickly but merely lost a prop and panicked killing all throttle as soon as the prop flew "rookie move for sure") So the second time i was trying to merely take off as slowly and subtly as possible which i'm starting to realize is one of my major downfalls. But i'm almost positive all firmware ect is consistent with the "A" (old style 2013) frame time.

      Thanks for the setup reference I'll definitely go over the yaw pitch ect... to make sure i'm within range!

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