[NSRCA-discussion] Ideas on radio beserkness-cause of crash??

[Robert Richards]

Instead of thinking of a battery failure mode as only being low or dead cells, you should also think of the case when a wire or welded strap breaks but continues to make intermittent connection aggravated by vibrations. I have not had this happen with a battery myself, but I have had this happen inside a servo and it caused the exact symptoms described here, but only for that servo.
   
  Sounds like everything in the plane was well proven, except for the battery and the switch. I would look very closely at both of those. (provided you find them!).
   
  Bob R.
  

Wayne Galligan <wgalligan at att.net> wrote:
          That sounds just like what happened when my Aries went in at Nederland.  Elevator and throttle oscillated and there was very slow response on controls just like a weak battery.  Post crash indicated a good charge on battery but I still think it may have had a bad cell. Only had one flight on it at that time.
   
  Wayne Galligan
    ----- Original Message ----- 
  From: Keith Black 
  To: General pattern discussion 
  Sent: Tuesday, September 02, 2008 11:24 AM
  Subject: Re: [NSRCA-discussion] Ideas on radio beserkness-cause of crash??
  

  I was standing next to Gray when this occurred. What I observed didn't look like a battery failure because the plane began violently oscillating in what appeared to me to be in pitch. This oscillation was so severe that I thought the plane was experiencing flutter. I told Gray to cut the throttle, at which point he said he already had. I looked at his transmitter and the throttle stick was indeed all the way down, however, the engine continued oscillating from high to low. I also looked at his battery meter on his TX and it was well into the black. A couple of times I thought the plane was going to fly off into the distance in this out of control manner but thankfully Gray was able to keep it close to the field.
   
  What's puzzling are the following:
   
  1. If it were interference the PCM would have gone into lockout.
   
  2. A combination of in and out of lockout fluctuations would not cause the throttle to go up and down since the throttle stick was down and the lockout was set to idle.
   
  3. If it were RX battery related I would not expect it to oscillate the control surfaces and the throttle, unless the RX freaks out at low voltage.
   
  Therefore, I believe this was some type of radio related failure either on the TX or RX side, most likely the RX. 
   
  One last thought, I have heard people report a bad servos in the system making all the other servos behave badly. Maybe someone has some feedback on this.
   
  Keith Black
   
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