Had my first Major Crash today

Discussion in 'Cinestar 8' started by David N Atkisson, Jan 17, 2013.

  1. Nick Wolcott

    Nick Wolcott Member

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    My sympathies David, I just had a crash myself, so I know the pain.
    I've read a lot of posts where MK electronics have failed while in PH or AH resulting in crashes.
    If I'm doing any operation where people are in the vicinity those functions remain off. Not that that eliminates any chance of malfunction (I just crashed mine in manual), but I think it dramatically reduces it. Those functions have proven unpredictable.
    All operations can be performed better and more accurately when in manual, I think if people want to protect their investment and people on the ground, they need to learn how to operate these things without PH, AH, or any of the other autonomous functions.
    I'm only talking MK here, maybe some of the other manufacturers (or future manufacturers:)) don't have these issues. I look forward to the day when my Cinestars will be MK free.
     
  2. Mark Melville

    Mark Melville Member

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    We've been trying to get ours up in the air for the first round of test flights with video. Weather permitting it should be this week. Right now for the test I have dinky hd cam, hardly any weight. Waiting on a GH3 but until it arrives I'm curious to see how stable the footage is with this camera. I've seen any number of solutions on this forum to improve stability. I guess I'll just have to wait and see.

    I have no problem balancing the gimbal (tilt and roll) but getting the pan balanced in relation to the airframe has been tough. I can't seem to get it perfect. It's very very close and I hope it's close enough not to make a major impact on the stability
     
  3. David N Atkisson

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    Hey guys,

    Thanks for your tremendous support during my time of crisis. I just got back from the Imaging USA Convention in Atlanta and the replacement parts hopefully will be in my mailbox. I few things to note. The booms where all tight but the impact on them drove booms 1, 2, 8 into the frame and all 3 where snapped off at the frame. A couple clamps where broken. When I first built my CS8 I didn't know how tight to tighten the clamps. In fact I actually tightened my initial clamps so tight they started to break the clamps and still I could turn the screws. How does one know how tight to screw these things together. That actually was one of my first issues when building this unit. Second, upon reflection of this even while I was in Atalanta I remember a little quirky behavior. Not sure it is actually the problem but I thought I might mention it so you guys could give me your feedback. Before I take off I have to calibrate the GPS before the CS8 will startup. I have noticed that sometimes when I get back after the flight my altitude is no longer at 0 meters it sometimes would say 2 or 3 meters. And the graupner confirmed this. Is it normal after flying to have you altitude to no longer at 0 meters when you land. This happened to me about every other flight or so. I just assumed it was normal and would recalibrate between every lift off. I do know of one other odd thing that happened a few weeks back when the lady in my ear told me I was around 1500 meters high. Even though I knew I wasn't and then the next announcement she made corrected it to around 150 meters which seemed more accurate to me. Could something be wrong with my flight control board? This only happened once that I can think of but maybe it was an indicator of something really wrong.

    Since I need to rebuild and get this bad girl up in the air again soon I would appreciate any advice of things to look for so I can feel safe about flying again. I have to admit I am a bit shacken but know I have to shrug that off and get back in the saddle so to speak but it seems there are a lot of points of failure and I want to make sure I do everything possible to try keep myself flying. I'm just glad this was a training flight and not a flight for a client who might not understand not getting their footage. Thanks again for all your help and support. If anyone wants to contact me directly I'm going to give my information. It might be easier to just chat then all this typing.

    David Atkisson
    Morningstar Productions
    Bus Phone: 760-864-9702
    david@morningstarproductions.com
     
  4. Steve Maller

    Steve Maller UAV Grief Counselor

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    Thanks for the update, David. I hope we can help you get to the bottom of this. Like any endeavor, you can't accomplish much if you don't have faith in your tools.
     
  5. Gary Haynes

    Gary Haynes Administrator
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    David I think the inaccuracy of the altimeter and distance readouts are normal, maybe not the 1500 meter reading, but generally when I was flying with the smart OSD I could land back on the same spot as takeoff and altitude and distance to home most of the time didn't read 0. Maybe Andy can let us know where the data for altitude is generated, GPS or the pressure sensor.

    Tightening the clamps I just do them 'firmly'. Just got one of the Hitachi 3DL2 electric screwdrivers. I compared the ratchet setting on it compared to how I hand tightened and found that I like the setting of 10 for most of the screws on the CS. Andy suggests at 13 setting for prop nuts. And if you don't have one yet get one. The speed of reassembly with the Hitachi is amazing with the number of screws that need to be tightened.
     
    Steve Maller likes this.
  6. Dave King

    Dave King Well-Known Member

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    Torque specifications are very important and shouldn't be by feel. How about a mini torque wrench like this?

    http://www.jensonusa.com/!HxCk2-n0B...dium=organic&gclid=CJGdw7Wu_7QCFQqk4AodKFUAOQ

    http://www.grainger.com/Grainger/WESTWARD-Mini-Torque-Wrench-6PAE8?gclid=CPK7qfOt_7QCFQSg4Aod0QIAPQ&cm_mmc=PPC:GooglePLA-_-Hand Tools-_-Wrenches-_-6PAE8&ci_src=17588969&ci_sku=6PAE8&ef_id=UK0ZDgAAUSQy4QTd:20130123205213:s

    When you assemble an engine, the manual tells you to torque to a certain specification, and those engines can't drop out of the air. You would just need a 1/4 to 2mm and 2.5mm socket.

    http://www.summitracing.com/parts/ttn-16147?seid=google&gclid=CPXfx-6v_7QCFUid4Aod7goATg

    http://www.walmart.com/ip/Titan-161...}&wl3=21486607510&wl4={aceid}&wl5=pla&veh=sem

    David: When I observe my C8 and I am right next to it I have gotten readings of 0 to 4 meters, so I think its very common. As I have learned while researching waypoints its very common for the electronics to be off 3 or 4 meters.
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    The AH is generated by a combination of both pressure sensor and GPS as I recall. I'll need to dive into the code again to confirm. Obviously, if you don't have a GPS, then it's just pressure sensor and even wind gusts register as changes in air pressure and altitude (hence the foam+heatshrink/Velcro ploy).

    As I mentioned to David in a PM, the air pressure sensor variations (excluding the 1500 meters) are normal and consistent with what I've seen and also with what Gary, Brad and I have seen as pilots of full-scale aircraft. (Think back to QNH and QFE -- oh, no, wait a minute, you don't use QFE here in the USA..that could explain some of my crappy landings in the sailplane! :) )

    Andy.
     
  8. Wolfgang Armin

    Wolfgang Armin Active Member

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    David, very sorry to hear about your crash.
    Just out of curiosity - you didn´t use two graupner transmitters and receivers for gimbal/cinestar?
    I had a crash once and that was the problem.
    Heads up,
    Wolfgang
     
  9. David N Atkisson

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    Yes that is true, I use the Graupner mx-20 for the pilot transmitter and receiver and I use a Graupner mx-12 for the Camera. Has anyone else had this as a problem. I had a half dozen flawless flights using these two Graupners. On another note I just got the main CS8 put back together today and ran into an odd situation maybe someone out there could comment. When I hooked up mk-tools for the first time since the crash I got all green lights except for the compass calibration. I guess it must have lost it somehow. But an odd thing, even though my GPS blue light is flashing like it has Satellite sync mk-tools is giving me an error code 5, which it says is a "No GPS Communication" I talked to the folks as Quadrocopter and they where a little flummoxed. I rechecked all the connectors and even switched out the little connecter between the GPS receiver and the navi-cntrl board and still I get the same error code 5. Any other ideas anyone before I ship my GPS off to get checked at Quadrocopter?
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Are both receivers bound to the same TX? If so, the second RX to bind, switches to a non-telemetry mode given that the Graupner documentation is to be believed.

    As to the Error 5, the blue light flashing is controlled by the logic on-board the GPS and is independent of the cable to the NC board so it's conceivable that your "terrestrial encounter" might have done something bad to the NC board. The prime suspects are the ribbon cables and mini-Molex connectors that are used for the board interconnects. As one of my programmers once said, after a three day investigation into a thorny bug, "something, somewhere is screwed...." :)

    Use MK Tool can you click on the GPS button and display the GPS satellite data?

    Andy.
     
  11. David N Atkisson

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    Unfortunately when I click on the GPS button no satellite data is shown. I can usually see 5 or 6 even from inside my house. I did swap the mini-molex cable from the one on the power distribution board and had the same results. Could the ribbon cables going between the NaviCntrl Board and the FlightCntrl board make this happen?
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I presume you do not see the UTC clock on the GPS screen either?
    In which case, yeah, the GPS board has broken off diplomatic relations with the FC board and the ribbon cables are implicated as the most likely possible cause. Do you have the wherewithal to make up new ribbon cables? There's nothing special to them.

    Andy.
     
  13. David N Atkisson

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    No but I'm sure I can find replacement ones at the local Hobby shop. They have a pretty complete selection of RC type stuff. Or I could order a few from Quadrocopter. I will try that first before I take any additional steps. I'm pretty sure the mini-molex cables are ok. As I swapped them out and I had no change in the error status. Thanks again Andy for that great sense of humor of yours. It makes this situation easier to deal with. LOL!
     
  14. Wolfgang Armin

    Wolfgang Armin Active Member

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    David, there are a few who had problems with two Graupners, and Holger from MK admitted that there can be problems.
    Here´s a post I made in another thread:
    http://forum.freeflysystems.com/ind...r-futaba-8fg-or-graupner-mx-12.203/#post-1807
    For me it was a question of distance. Within a certain distance everything was working properly, but as soon as I was flying further away, it lost signal and came down. I didn´t have any GPS activated back then so I can´t tell whether fail safe and comming home would have done anything.
    I used two receivers one for the gimbal and one for the copter. One bound to MX-20, one to MX-16. I changed to Spectrum on the gimbal and the problems were gone.
     
  15. Wolfgang Armin

    Wolfgang Armin Active Member

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    I think it should be noted somewhere prominent that there can be problems with two graupners. Beside financial aspects it can be quite dangerous when a big bird like a cinestar comes down uncontrolled. Same with others of course!
     
  16. David N Atkisson

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    Hi folks,
    I read the thread about 2 or more Graupners on the same system. I use the mx-20 for my pilot transmitter and my mx-12 I use for the camera gimbal and control of camera. One of the things I did but didn't seem to realize it might be a problem was that just before taking off we where fiddling with the Dual Rate/Expo on my mx-20 transmitter. I set the percentage to 50% on the dual screen and found that the CS8 wouldn't start. We where actually trying to set the Expo so I could have a little less sensitivity in my throttle. By doing that of course I couldn't get the CS8 to even start up because I couldn't calibrate so I set it back to 100%. Andy has since helped me out with that setting. Anyway the thread above mentioned not to program the units with both transmitters turned on could this have cause my crash. both receivers are less then a meter apart. One on the circular part of the frame and the other down on one of my landing gear legs. All was flying well until I was around 75 feet out and around 50 feet up in the air and then thats when she started to plummet and I had no control. Just trying to understand anything that will help me out as I have no flight data to look at.
     
  17. Wolfgang Armin

    Wolfgang Armin Active Member

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    David,
    I didn´t do any programming with both transmitters turned on and still had the issue. You could just make a few transmission tests without the copter in the air, just move with your radios and watch the graph on your radios. I wasn´t clever enough to do that back then ;-). That should give you an idea.
    A question: did you ever had the system fly further away than those 75 feets before the crash?
    Cheers,
    Wolfgang
     
  18. Dave King

    Dave King Well-Known Member

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    I think you need to start a rather good guide for witty quotes!
     
  19. Dave King

    Dave King Well-Known Member

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    Well I just bought a MX12 for the video camera operator. Is there anyone that "IS" using a MX20-GR24 for the copter and a MX12-GR12 for the video camera operator? If there isn't anyone here using it successfully I think it might be time to put the MX12 on Ebay.

    Question 2: For those that are not using a 2nd Graupner radio-receiver for the video camera operator what are you using?
     
  20. Gary Haynes

    Gary Haynes Administrator
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    I looked at a bit of the other posts. Holger seemed to indicate the issue was apparent when both receivers were transmitting telemetry data. So if you don't plug into the telemetry port, which I don't think you for the gimbal receiver, maybe there wouldn't be the issue? In the early multi receiver setups prior to Radian folks were using a second MK FC board and may have been setting up the usual way with the data signal going to the T port on the receiver.
     

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