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DX8 setting

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Old 01-15-2013, 09:21 PM
  #1
David DeWitt
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Default DX8 setting

I lost a plane today rolled hard left and full up elevator at a low altitude I was testing the new EVO 10 cc gas engine in a Ugly Stik, the plane had about 5 flights on it. After checking over the system everything works ok. But I noticed I had the DX8 transmitter set for DSMX with a AR700 DSM2 receiver. Could this cause the problem. I didn't know the AR700 would work at all with the transmitter set on DSMX mode?
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Old 01-15-2013, 11:55 PM
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Default RE: DX8 setting

You mean AR7000. The Tx protocol setting isnt an issue.it will simply bind and operate in DSM2 regardless of setting.Look on the upper right corner of the mainscreen when it is operating and you will see DSM2.This is the mode it is bound and operating in.The only reason to change the mode on the Frame rate screen is if you want to force a DSMX Rx into DSM2 mode.
Were you using telemetry? Did you check the Flightlog data after the incident? What was the minimum voltage on the Rx bus? Without this information any diagnosis is going to be a pure guess.
When control was lost did the throttle return to idle? Without any other info whether or not the throttle went to failsafe may be the only clue to what may have happened.
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Old 01-16-2013, 04:36 AM
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Default RE: DX8 setting

Flight Log data would tell you if you lost communications (i.e. you would see a "hold"). But you can't take the power off the receiver before you read it, if you are using a data log reader. I am pretty sure the data would be stored in the DX8 if you are using telemetry, until you shut that off.

Pre-set Failsafe could tell you also, if you set it correctly (i.e. the throttle would drop to your pre-setting on a "hold".) Also, a servo may have failed. I had an aileron servo jump to and lock in the full UP position. Flipped the plane right over shortly after take-off.


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Old 01-16-2013, 05:56 AM
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Default RE: DX8 setting

The AR7000 receiver lost power in the crash, battery plug pulled out of the receiver. A123 battery had 6.6 volts, fails was set for low throttle and neutral on all control surfaces. I had a telemetry module in the plane to monitor engine temp, rpm and rec voltage.
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Old 01-16-2013, 05:59 AM
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Default RE: DX8 setting

The AR7000 receiver lost power in the crash, battery plug pulled out of the receiver. A123 battery had 6.6 volts, fails was set for low throttle and neutral on all control surfaces. I had a telemetry module in the plane to monitor engine temp, rpm and rec voltage. The best I could tell the engine did not throttle back and was buried about 6 inches in the dirt.
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Old 01-16-2013, 06:09 AM
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Default RE: DX8 setting

Failsafe will not work ifbattery plug came out of receiver or you have any total loss of receiver power for any reason your receiver can not go to failsafe. The servos will remain in the position they where in when power was lost. Failsafe requires power to move the servos to failsafe position, this happens when signal is lost or when power is present but not enough voltage for reception of signal, not when power is totally lost.
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Old 01-16-2013, 06:16 AM
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Default RE: DX8 setting


Quote:
ORIGINAL: David DeWitt

The AR7000 receiver lost power in the crash, battery plug pulled out of the receiver. A123 battery had 6.6 volts, fails was set for low throttle and neutral on all control surfaces. I had a telemetry module in the plane to monitor engine temp, rpm and rec voltage. The best I could tell the engine did not throttle back and was buried about 6 inches in the dirt.
With a Spektrum Rx, Failsafe kicks in when the Rx loses the signal from the Tx. If your Rx lost power, there is no Failsafe Event, no record of Flight Log Data, and the control surfaces move which ever way the wind pushes them. No control.
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Old 01-16-2013, 08:15 AM
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Default RE: DX8 setting

Receiver lost power after the plane hit the ground, battery with switch harness was several feet away from the receiver.
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Old 01-16-2013, 08:23 AM
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Quote:
ORIGINAL: David DeWitt

Receiver lost power after the plane hit the ground, battery with switch harness was several feet away from the receiver.
Now, ... that is a crash!

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Old 01-16-2013, 10:50 AM
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Yeah that can be a tough one if everything was powered down on impact.The numbers on the Tx display may not fully reflect the situation at impact.Were you using the logging feature?
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Old 01-16-2013, 01:53 PM
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Default RE: DX8 setting

What a bummer. Did you also destroy your new GX10?
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Old 01-16-2013, 04:35 PM
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Default RE: DX8 setting

Lucky enough the engine survived with very little damage, just a bent fuel nipple on the carb. This Evolution 10cc is going to be a great motor, a gallon of gas is going to last a long time. Everything happened so fast, I was flying at about 30 feet when I lost it. I now think the receiver went into fail safe because the carb was full of dirt but the throttle barrel must have been closed on impact so no dirt got in the motor. The radio is working perfectly on the bench.
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Old 01-16-2013, 07:40 PM
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Default RE: DX8 setting

Good to hear your new engine survived it!
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Old 01-16-2013, 08:51 PM
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Default RE: DX8 setting

If it went to failsafe, then it was most-likely a communication loss. Given that I fly my Giants way out there, I doubt it was the DX 8. ( I have two DX8s). Did you ever read the flight data to confirm that your Rxer and Remote Rxer were positioned optimally? Were there any wires or conductive material by them? I once attached a remote Rxer with silicone sealant and it was registering 3 times a many fades as the other two remotes, which were not fastened in place with silicone. I removed the silicone and used servo tape the now the fades are nearly identical on all three Rxers, each flight. Did you have the remote Rxer installed? Did you do a range check?>>

I would rebuild and do a "positional Range Check." (i.e. Have someone move the plane around to all angles, etc. while in the range check) and then read the flight log data. That will tell you if you got things positioned correctly or have an RF interference. I would even try this with the engine running and do it about as long as you ran the plane when the plane crashed. >>

The data log readers are invaluable when you are trying to troubleshoot this kind of problem. The readers are worth their weight in gold, if you are not using telemetry. If you have telemetry going, the Flight data reads out on the DX8. You can use that readout “real time” to gage how far you really can go out there w/o loosing the plane. You see fades = no problem. You see a lot of rapidly accumulating fades = watch closely. You see a couple rapidly accumulating frame losses = you are getting close to the limit. Once you see a hold, then you better have her turning around back to you. A hold registers when you have lost the connection to the plane. Several holds and you most-likely have momentarily lost control of the plane>>

http://www.horizonhobby.com/products...ht-log-SPM9540.
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Old 01-17-2013, 08:12 PM
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Default RE: DX8 setting

OK thanks, I will give it a try.
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Old 01-18-2013, 04:55 AM
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Default RE: DX8 setting

I read through this thread with great interest.  You observed full left aileron... (roll left), full up...  (nose up)  Evo 10 plenty of power for a stick so I'm guessing that the plane looped, and rolled inverted before contacting the ground. I'll bet there was a rudder component as well. So, for me, the question becomes, "What would drive all servos to their extreme's?"

I never see ANY fades or Frame losses, and even if you did have a RF link problem, its doubtful that link loss is going to drive all servo's to their extreme.  Since you are flying a gas motor, I really doubt battery problems..  besides you said that bench testing the system everything works.  Are you bench testing with the same airborn pack?

I have a good deal of experience with the Ugly Stik, and it is a pretty solid airframe, but is it possible that the aileron hinges on one side came out?

Another personal "Pet Peeve"  and constant harp of mine is the current lack of concern that new modelers have for metal to metal contact.
Everybody assumes that modern day 2.4 Ghz radio's are immune to spurious RF, but I still bow to the electric Gods and have NO metal to metal contact or for that matter use of fuselage long wire rods. (I use Nylon rods).

I would like to know more about what you find and suggest you really dig into potential reason for failure.

Thanks

KKKKFL
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Old 01-18-2013, 06:51 AM
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Default RE: DX8 setting

I was at low altitude when I got full left aileron and full up and maybe rudder. So it rolled inverted and full up into the dirt. This was a kit built ugly Stik and has been flown several times with this AR7000 receiver and a Jr 9303 transmitter and a OS 46 nitro engine. I had just installed the 10 cc ignition engine and set up my DX8 with telemetry so I could monitor engine temp and rpm on the new motor. It flew 4 or 5 times ( not the same day) with no problems prior to the crash. I had a lot of equipment stuffed in the fuselage with two A123 1100 mah batteries, receiver, telemetry module, 2 switches, a electronic engine kill ecu and 3 servos. The ignition module was behind the firewall under the 8oz fuel tank. The plane was well built and had Robart hinge points on all flying surfaces. Maybe just too much electronics in a small space. Yes the bench test was done with all the equipment that was in the crash including same batteries. I have been flying this DX8 with a Balsa USA 1/3 scale Stearman with a Moki 215 ignition engine and gas helicopter with no issues. The only thing I can come up with is some kind of interference caused the crash.
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Old 01-18-2013, 09:59 AM
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Default RE: DX8 setting

Did you have the ignition on a separate battery? Do you have a non-conductive throttle linkage? The Rxers also need to be away from conductive material, as I mentioned before. They also need to be away from anything connected to the ignition system. Are you using the two batteries with the Rxer and using a BEC for the ignition? That is a setup for failure.

But, the only thing that would drive them full up would be a failed servo or pilot error. Given that two servos failed simultaniously, that rules out failed servos.

I would do the positional range check and check flight log data. If all the Rxers' fades are about the same and you get 0 frame losses and 0 holds, I would fly it.

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Old 01-18-2013, 12:26 PM
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Default RE: DX8 setting

I had a separate switch and battery for the receiver and ignition module, no BEC. I think I will put it in a beater plane and separate the electronics further apart and test fly it to see how it works.
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Old 01-22-2013, 04:47 PM
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2.4 radios are not imune to ign interference. Couple of things. A buddy went to take off with his 1/4 scale gasser and when he opened the throttle it went full down elev. and full right rudder. When he throttled back everything was cool. I was standing beside it when he tried again. On opening the throttle, I noticed the plug wire was being blown back from the plug from the prop wash. The ign arcing was causing the interference. We plugged the cap tight onto the plug and everything was fine. In another case, a guy was cranking on his gasser to start it and every it turned ofer, the control surfaces would go crazy. I noticed the plug had LAWN MOWER written on the side of it. This was on a Quadra motor and as you know, they require a resister type plug. Had one in the truck and stuck that in it and away it went with no interference. Something to check out.
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Old 09-22-2013, 06:57 AM
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Need advice. I left my DX8 transmitter turned on over night. Not sure of the number of hours it was on when I discovered that I forgot to turn it off. I have the lipo battery installed in the transmitter and it was reading 7.4 volts on the display. I had accidently left the throttle at about half throttle and the warning beep was what caught my attention. I have turned off the transmitter and plugged it in for a full charge. Will this lipo battery be OK? The battery alarm was not sounding, it was the high throttle alarm that was going off. Battery alarm is set to 6.4 and battery type is set to LIPO on the transmitter. How long should it be left on the charger?
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Old 09-22-2013, 11:58 AM
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Batt will be fine. Leave it on the charger and when it's fully charged, the red light will shut off.Should read 8.4 volts, or close to it when its done.
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Old 09-22-2013, 12:35 PM
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Thanks....just checked battery and it has charged up from 7.7 to 7.9 volts. So it is charging like you said. Thanks for the response.
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