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-   -   DX8 issue inside metal buildings (http://www.rcuniverse.com/forum/jr-radio-spektrum-radios-116/10306188-dx8-issue-inside-metal-buildings.html)

jschenck 02-01-2011 07:40 PM

DX8 issue inside metal buildings
 
Hi all - I'm hoping to find some help here with an issue that three of us DX8 owners have seen. Lots and lots of of information that all boils down to this:

I have had an issue with loosing control of my AR61x0 receivers inside a metal building. The other two guys in our club that fly there have also had the same problem. It is easily reproducible and consistently occurring. Almost all the pilots in our club fly DSM2. DX6i,DX7, X9303 - they don't seem to be affected. I've been seeing issues now for about 2 months. The other two DX8 owners are ready to get rid of their radios and go to another brand. I know I flew my DX8 since the day they were released with no problems outside, exact same heli's. But inside flying is causing constant problems.

Here is some of the details. I've copy/pasted some of this information from my posts on runryder
Quote:

I've also been having lock out's and complete control loss in the same flying area with <other pilot>. 3 of us with DX8's flying with a bunch of 9303's and DX7's. No body else seems to have much trouble but every time and I do mean every time I fly with my DX8 the AR6100 comes back flashing. It usually happens within 30 seconds. I've had the RX start flashing several times after I've initialized the heli and just sitting at the flight line before applying any power to the motor.

The part that is so confusing to me is I can fly the exact same heli outside and not get any problems. Did this a few weeks ago. Had a flashing RX. Didn't even change the battery. Wen out into the parking lot, re-init the TX/RX flew for a few minutes no problem. Didn't even power off, come inside and the RX is flashing within 30 seconds.


My 250 went in hard yesterday, full loss of control for over 30 seconds. Sitting there looking at it and BS'ing the RX "comes back", controls work normal and LED is flashing. This may be a bad RX, I'm going to buy a new one.
Quote:

the other two DX8 owners have AR6110's that have the red and orange LED's. Solid orange, flashing red. I borrowed an AR6110 and got the same results.

IIRC solid orange = no power problems. flashing red = hold.
Quote:

There's not a common setup - one of the DX8 pilots is flying his foamies and had one nose dive - no control flashing red LED on the AR6110e. For the others we have a bunch of different brands on the 250's and 450 packs. And again on the AR6110's the orange light is solid (no power loss).

The really relevant pointer here is that for <other pilot> he had zero problems with the exact same heli when flying with his DX6i. I'm going to use my X9303 for the rest of the inside flying season to see if this problem shows with consistency like I'm seeing with the DX8.

For me, I have yet to experience a 'flashing LED' after flying outside. Since I got my DX8 in September this left me with a lot of confidence in the radio. Now after 2 months of indoor flying I can say I get a 'flashing LED' every single time I fly indoors, 90% of the time within 1 minute into the flight. I had a few wrecks where it was clearly a loss of radio contact. I got to the point where I could recognize it because there is a slight bump in the collective when it happens. Binding with the collective in the center position has really hidden that now so I now and just looking for the flashing LED.
and finally my theory -
Quote:

100% speculation but is it possible when the DX8 is in 22ms mode it's sending out the same 'packet' twice with the understanding that the 22ms RX will only pickup on one of them. A reflection of that is getting back to the RX and confusing it causing it to reset.
I hope it's ok to post links to another forum on this discussion
http://rc.runryder.com/helicopter/t629622p1/

jschenck 02-01-2011 07:53 PM

RE: DX8 issue inside metal buildings
 
I know the experiences with the other DX8 guys differ some in details to mine, specifically they've seen resets/flashing RX's during setup at their house (not inside a metal building). They've both lost confidence in the radio and are unwilling to trust large heli's or airplanes with them. We all really want to be successful with this radio since it has such great features. Telemetry was the reason I committed to buying a DX8 months before they were released.

I have heard from at least one other heli pilot who experienced similar issues also reported on RR. His solution was to run RX's with satellites on everything. Unfortunately for one of the other guys in our club he bought some AR6200's and still got the flashing RX. Sometimes on just the remote RX, sometimes on the main RX.

thoughts ?

804 02-03-2011 06:28 AM

RE: DX8 issue inside metal buildings
 
I flew my Gaui 425 from late September thru early winter with a 6200, no issues, probably about 80 or so flights.
One day with temps. in the low to mid 30's, I was hovering about 3 feet up and the heli went full negative pitch into the ground.
I pm'd Andy Kunz with Spektrum, he said with brownouts, the system goes temporarily into a "bind-like" mode where it does go full negative.
I attributed this to the Li-Pos being cold, but haven't tried it since.
I was sort of shaken and didn't notice whether lights were flashing or not. But, I do remember only one time I landed with light flashing,
and it did not result in loss of control.

Lately, I've been flying a T-Rex 250 with a 6100 inside an indoor sports arena, which is built like a large pole barn.
It is steel I-beam construction inside, but I'm not sure of the shell construction. I'll check and let you know.
Anyway, out of maybe 25-30 flights, I have 2 incidents of the rx flashing, but no loss of control.
I also have many flights with some BNF's, and no trouble.

Wish I had some answers for you, but the above are my only experiences.

Edited to add.
forgot to mention I'm using a DX8, most of the flights have been with the updated 1.04 version.
I've seen some talk of the 1.04 causing flashing light with 6200 rx, but that has not been my experience.

Btw, have you seen this: http://www.spektrumrc.com/DSMX/

jschenck 02-03-2011 08:33 AM

RE: DX8 issue inside metal buildings
 
I'm holding some hope that the DSMX will help us out.

I do think the type of building we are flying in makes a difference. Again, exact same equipment flying outside, no problems and it's at least 30 degrees colder outside

To be 100% clear there is no way this could be a power issue. It is reproducible with every flight. When it hit's the AR6110's the orange light is solid, red light flashing. The documentation says this means the RX went into HOLD (red flashing) but no power loss (solid orange).

Other guys have contacted HH directly and have even sent their DX8's in. Got back "it's an RX power issue" as the only answer so far. It's not a power issue. Exact same equipment has no problems being controlled with a DX6i.

804 02-03-2011 09:54 AM

RE: DX8 issue inside metal buildings
 
Just ran some errands and drove by our indoor site.
It is all metal, sides and roof, probably about 100 by 200 feet and maybe 30 feet at the peak. It is all insulated inside.
My rx is a 6100e, at least 2+ years old.

As far as I know, I have the only DX8 there, but lots of Spektrum, a couple A9's, and some Futaba, all 2.4.
Just haven't seen any problems.
I did have to send mine in to replace the elev/ail. gimbal.

Have you played around with rx location to make sure the antennas are not blocked?
I've seen some threads somewhere, I think on HF or RR that point out how critical placement is,
especially with CF heli frames.

Also, could there be any communication equipment inside, or video that could cause interference?

With all the indoor flying going on, I'd think that if your problem is widespread it would show up more.
I frequent all the major forums and haven't seen anything like you describe.

You may just have to send it in, with your rx's, describe exactly what is going on and
try to get it fixed.

I know it sucks, and I feel for ya'.
Good luck, if I see anything I'll send it your way.

jschenck 02-03-2011 10:21 AM

RE: DX8 issue inside metal buildings
 
Well the RX placement doesn't make sense here either because we have seen the issue on 6 or 7 different aircraft including a foamy. I had the AR6100 strapped to the outside of the frame on my Trex-250 with one of the antenna pointing down below the bottom of the frame. I also have some old RX's one of them doesn't even have the quick-connect feature (I can't tell if/when it gets a hold).

The thing that really points away from a problem on the receiver side is that the exact same heli flying on a DX6i = zero problems. No flashing RX at all. Put it back on the DX8 and get a flashing RX.

jschenck 02-03-2011 10:24 AM

RE: DX8 issue inside metal buildings
 
Man I wish I had an AR6115e in my hand to see if that would act different in our inside flying.

http://www.spektrumrc.com/Products/D...dID=SPMAR6115E

renglishjr 02-03-2011 10:26 AM

RE: DX8 issue inside metal buildings
 
I am one of the other DX8 owners that jschenck is referring to and have sent the radio in for the issue. It came back with a clean bill of health, but immedialtely had the same problem the next time I flew. I don't think the problem is widespread, but has happened to others outside of our group - here's a video from youtube showing the same exact thing occuring during a flight in a gym: http://www.youtube.com/watch?v=J1qaPaH0-8g.

There was, of course, a problem with the vibration unit in certain production lots that produced the same symptom and resulted in a recall, but this is different. Same symptom, but no alarm. I believe all of our DX8's are from the affected recalled lots and have had the problem corrected by Horizon. Maybe it's just with those early production units and there's a second issue that hasn't been identified? Guess I'm grasping at straws here.

804 02-03-2011 11:15 AM

RE: DX8 issue inside metal buildings
 

Quote:

ORIGINAL: renglishjr

I am one of the other DX8 owners that jschenck is referring to and have sent the radio in for the issue. It came back with a clean bill of health, but immedialtely had the same problem the next time I flew. I don't think the problem is widespread, but has happened to others outside of our group - here's a video from youtube showing the same exact thing occuring during a flight in a gym: http://www.youtube.com/watch?v=J1qaPaH0-8g.

There was, of course, a problem with the vibration unit in certain production lots that produced the same symptom and resulted in a recall, but this is different. Same symptom, but no alarm. I believe all of our DX8's are from the affected recalled lots and have had the problem corrected by Horizon. Maybe it's just with those early production units and there's a second issue that hasn't been identified? Guess I'm grasping at straws here.
In that video, it sounds like the headspeed was constant, meaning that somehow un-commanded negative pitch was introduced.
That is exactly what happened to my Gaui outdoors.
My DX8 was also one of the early ones, and that was after sending it in for the replacement gimbals, and they "fixed" the vibrating alert feature. I never used that anyhow.
I asked the Spektrum guy (Andy) if the un-commanded servo inputs could be a result of the audible alarm, (mine went in just after the 1 min. alarm went off), and he
emphatically said no.

Dang, I was starting to feel confident in this radio again.[&o]

renglishjr 02-03-2011 11:50 AM

RE: DX8 issue inside metal buildings
 
Sorry 804. Didn't want to bring you down about yours - and don't get me wrong, this is a GREAT radio - especially for the price. With the move to DSMX, and as long as this problem gets identified and fixed, it doesn't sound like there's any other radio out there that's going to be able to touch it. We're just hoping that someone out there has a solution.

jschenck 02-03-2011 12:16 PM

RE: DX8 issue inside metal buildings
 
I agree - I've used my DX8 (PID H008X) since September. I immediately started flying my heli's with it and didn't have any issues including flying the same Trex-250 and 450 with the same RX nearly out of site (I like doing "from way up there" auto's). Never saw the issue until we started flying inside a big metal box. I still have a high confidence in flying my DX8 outdoors because I haven't seen an issue with mine.

I have heard/read that some folks hare having issues with the AR6200. May wanto to search and read up on that.

804 02-03-2011 12:35 PM

RE: DX8 issue inside metal buildings
 
Okay, I'm a bit confused. (not unusual):D
jshenck, when you say you lose control, do you mean that the servos simply stop responding and the heli continues on as if the servos are stuck in the last commanded position, or, do you mean an uncommanded servo input
like in the video renglishjr linked?
Does the motor continue to run?

And same question for renglishjr.

jschenck 02-03-2011 01:10 PM

RE: DX8 issue inside metal buildings
 
Most the time it happens so fast that I don't notice anything other than the flashing RX. When I have noticed something it's a momentary 'blip' or jump in collective which I can only assume is the RX going into fail-safe. We usually bind with the throttle all the way down so failsafe is full negative collective.

This experience has taught me to bind my heli's with the collective in neutral position, in throttle hold. With that setup I don't notice it anything other than a flashing RX.

Having said that I've had two instances where I got 100% full negative collective with full power uncommanded. First time my 450 was upside-down. It took the length of time to go from 1' off the ground to hitting the (guess here) 30' ceiling which was plenty of time for me to react. most of the heli came down in one chunk. I don't remember if the motor or battery came out but it didn't have power on the main rotors on the way down, presumably my throttle hold may have taken by then - I've trained myself to hit th.hold on impending impact. The 2nd time the 250 was in a hover about 3' and slammed itself in the ground and did a little chicken dance before powering down. When I went over to it I didn't have any control of any servos, no LED on the RX at all but the gyro lights were on and the servos were holding their position. ~30 seconds later I got control back, did nothing but look at it. Now it's possible that this was the same RX in both cases since I've been swapping RX's around trying to troubleshoot the spontaneous flashing RX issue. this could be a bad RX which isn't related to the flashing RX, I just don't know.

I did put a very old AR7000 which does not have the quick-connect feature into my Trex-450. I haven't had any loss of control on that since.

jschenck 02-03-2011 01:13 PM

RE: DX8 issue inside metal buildings
 
In the two instances where I got 100% negative collective I may have had the fail safe set at full negative collective. I would suggest setting failsafe at zero pitch, throttle hold on.

804 02-03-2011 01:36 PM

RE: DX8 issue inside metal buildings
 

You are having problems indoors, and I'm not, using the same rx and in a similar environment,
and I had a problem outdoors with a different rx, and you're not, and...my head is spinning.

I gotta think my problem was power related with the cold Li-po's.
Yours, dang, no idea.

I'm gonna hopefully fly Sat. nite, and I'll take my spare 6100 and try it and pay attention to the lights.
I'll be back.;)

renglishjr 02-03-2011 03:12 PM

RE: DX8 issue inside metal buildings
 
To answer your question, 804: I always get the uncommanded servo input. The first time it happened (to really throw a wrench into things) my 250 went into an uncommanded full-rate pyro for about 5 revolutions, stopped the pyro and immediately went into uncommanded full negative ptich and slammed into the deck. Every time since, I've just gotten the full negative pitch. I'm always in idle up when this happens, so jschenck may be right about stick position on bind. Will have to try it this weekend flying in normal mode and see if it's actually going into failsafe or something else is happening - I don't think we've tested that.

By the way 804, welcome to our nightmare - my head's been spinning on this for weeks.

804 02-03-2011 07:12 PM

RE: DX8 issue inside metal buildings
 
Any way you could test inside a couple of different structures, say a metal pole barn and then a non-metal garage?
Just do some some hovering.

Would be some trouble, but maybe worth it.

jschenck 02-04-2011 08:04 PM

RE: DX8 issue inside metal buildings
 
We do fly in a couple of different buildings. The Hobby Town here is a similar building and guys have seen the flashing RX issue and even crashed in there. I haven't heard of anyone having problems at the indoor soccer center or flying in the baskeball gyms we fly in but we also don't hit those areas as often.

Just found out that the AR600 is not only a DSMX receiver but is also Flight log capable. I may see if I can track down an AR600 and a TM1100 so I can see what is going on. Even if I just get an AR600 I can use a Flight Log device to see the information, which I have one of those.

I also indent on setting up some more methodical tests where I'll set a couple of different type RX's, 6100's, JR 921, AR8000 across the room and let it sit there powered on linked up to the DX8 and see if they get resets - not installed in any aircraft. Then try the same test after binding to my 9303.

Going to get a bit methodical about my testing here - If I can get the time to do this Sunday. I have some family obligations also.

Cherokee Flyer 02-05-2011 06:01 AM

RE: DX8 issue inside metal buildings
 
What happens if you change the frame rate? most of the listed receivers have a slower supported frame rate.

L.

jschenck 02-06-2011 07:50 PM

RE: DX8 issue inside metal buildings
 
Today I setup my DX8 bound with a JR 921 and a TM1000. I put the 921/TM1000 on the other side of the room and left it there for over 1/2 hour. The DX8 didn't report a single frame drop.

I was going to perform the same test with my DX8 and an AR6100 but my test AR6100 wouldn't go into bind mode.


I also flew my 250 for 8-9 batteries, not a single instance with flashing RX lights. RX is an AR6100e V1.6 - I was flying with my X9303 the whole time.

Another DX8 (renglishjr from above posts) guy flew an foamy airplane with a new AR600. He never noticed a loss of control but it did come down with a very clear solid orange light(no power loss) and a single flash RED light = HOLD.


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