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Signal Loss with Spektrum?


ben goodfellow  1
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pilot error is the one thing im 100% sure it wasnt it didnt stall ,it abrubtly dived for the ground a spitsecond after the engine cut . i would class myself as a goodish flyer and would know the difference .i would love to put it down to pilot error if i had the slightest thought that it was i would but cant there fore has to be a problem with the control system

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Can we just clarify one issue Ben. Several times you have said "dived into the ground" or similar. Now if you were on approach, presumably slightly nose down, and the engine stopped and the control surfaces went to neutral - what would happen?

Well I think the model would drop its nose a bit more and attempt to take up its stable glide slope. Now Ok, that's going to be too steep for a comfortable meeting with mother earth - but I wouldn't have described it as a "dive".

So are you saying that it really did "dive in" - like some down elevator was in place - or was it just a steep glide slope?

I'm asking because if it was the former - and your F/S was set to neutral control surfaces - then possibly there is more going on here than we think.

BEB

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I have great sympathy for Ben, having been there myself. Mine did almost the same. You go out to fly a plane and it goes in without any reason.

I was flying towards me, I noticed the plane slowing up, it went into a 45 degree dive, didn't respond to commands. That was the end of that...

My failsafe had to be independently check before the start of the show so I know that it would go into idle and the control into neutral. I cannot understand the abrupt dive. If anything it should have lost height gradually as it was on idle.

Im still convinced that "hash " interference and a Rx brown out of some sort was the cause. With loss of signal to the Rx it takes a couple of seconds to re-establish and power up, so to speak. When that's complete you are walking over to wreckage.

Others may have a different view

Edited By cymaz on 04/01/2015 13:26:01

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Posted by cymaz on 04/01/2015 13:24:13:

I was flying towards me, I noticed the plane slowing up, it went into a 45 degree dive, didn't respond to commands. That was the end of that...

Put like that, your incident sounds like a classic stall, cymaz? Were you flying upwind or downwind at the time?

Pete

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I have seen a 2.4 Spektrum model on the ground 'glitch' when another Spektrum radio was switched on. My wot 4 was sat in the model restraint, and someone else switched on a DX6i nearby and one aileron servo glitched to full deflection and then everything returned to normal. My conclusion would be that although it's rare is seems possible for a Spektrum receiver to interpret somethig that's not a signal command as a signal command. I've never seen it since, and have now moved to another protocol.

As has been pointed out, pure loss of signal should be ruled out as the behaviour of the airframe wasn't what would be expected from a failsafe. one other thought... Does the model ever flutter or offset the servos when the power comes on and as the receiver initialises. If it does maybe that's the issue here. Power to the receiver was lost momentarily and the uncommanded dive caused by offsetting occurring during initialisation?

I doubt it was a stall. The model in question would be very unlikely to behave like that in a stall. We are talking about a big aerobaticsI'm with very low wing loading, not a warbird. 

 

 

Edited By GrahamC on 04/01/2015 14:17:20

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never really noticed any flutter /twitching but thats not to say it never happened in flight it would beeasy to spot as it was so responsive , id really like to get the root cause of this ,and i image all the spekky users reading this thread will be interested too.. i am going to get them sent off and very much look forward to hearing waht hh have to say.

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Ben, I don't think this will answer anything, but when I used to use Spektrum, some models would deflect surfaces at the moment of Rx switch on. They would then settle at neutral when the Tx and Rx were speaking to each other properly.

If you switch on your Tx, then your Rx, does the elevator blip down and then back to neutral?

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Posted by Chris Bott - Moderator on 04/01/2015 14:40:59:

Ben, I don't think this will answer anything, but when I used to use Spektrum, some models would deflect surfaces at the moment of Rx switch on. They would then settle at neutral when the Tx and Rx were speaking to each other properly.

If you switch on your Tx, then your Rx, does the elevator blip down and then back to neutral?

Once everything has been set up you need to rebind to stop the above happening

Stops the retracts collapsing when switching on the model

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Hi. As stated previously I have seen this exact problem before with Spektrum gear when a previously well flown model at close range suffers motive power cut (IC /Electric),followed a second later by full down elevator and nothing the pilot can do. My Easyglider was right in front of me on a slow pass when this occurred and the pause before the full down occurred was noticeable. The mud saved any real damage and all equipment worked when I walked the 80 feet to the model. I put it down to DSM2 but Ben was flying DSMX and still same experience. I have owned my DX9 for a Year now and only one glitch as above. Bet HH find nothing wrong ! And I love my DX9 !

Colin

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Hi guys, although not in the dizzy heights of the fine models you fly with, A Bixler I flew, thrice went in to failsafe when about 100m from me. I blamed his on the Specky kit and had a nice email conversation with them. They felt it may have been power supply as when I lost any sort of control, onlookers witnessed the motor revving up and down with random flight patterns. It managed to disassemble itself on the third event! I replaced it with a Phoenix (a similar leccy pusher glider) and used the Spektrum kit (AR 6010, DX7s) and included a Spektrum flight log. I have flown 15 sorties the longest being 28 minutes. I have had no control problems at all despite being over 250m away and 400 feet up. The log has registered no fades or holds. I have been meticulous in posiioning the RX and satellite RX antennas well away from anything that can interfere- there are bits of carbon in the Bixler and Phoenix.. So my kit is OK. On the bench I carried out a load test on the Bixler's old ESC. After 4 minutes at an average of half engine revs it started to cut in and out. It wasn't warm so I now assume it is failing internally. It is now in the bin.

Edited By Dane Crosby on 04/01/2015 15:01:49

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Posted by bert baker on 04/01/2015 14:46:45:
Posted by Chris Bott - Moderator on 04/01/2015 14:40:59:

Ben, I don't think this will answer anything, but when I used to use Spektrum, some models would deflect surfaces at the moment of Rx switch on. They would then settle at neutral when the Tx and Rx were speaking to each other properly.

If you switch on your Tx, then your Rx, does the elevator blip down and then back to neutral?

Once everything has been set up you need to rebind to stop the above happening

Stops the retracts collapsing when switching on the model

Yep I know that Bert, was going to come on to that after Ben had checked to see what his does.

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Posted by WolstonFlyer on 04/01/2015 15:16:39:
Perhaps get or borrow a Spektrum Flight Log SPM9540, it will record any signal fades, frame losses, brown outs / failsafes and also receiver voltage during a flight.

Spoke to spektrums ( I think it was them ) about this a long time ago, basic answer was yes you can log problems but what then what are you going to do.

 

Edited By bert baker on 04/01/2015 16:10:29

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Posted by Pete B - Moderator on 04/01/2015 13:38:17:
Posted by cymaz on 04/01/2015 13:24:13:

I was flying towards me, I noticed the plane slowing up, it went into a 45 degree dive, didn't respond to commands. That was the end of that...

Put like that, your incident sounds like a classic stall, cymaz? Were you flying upwind or downwind at the time?

Pete

Upwind, half throttle, straight and level !

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