Warning X8R RX - do not use with CDI on IC powered 'planes

[Ron Gray]

There are more than a few X8Rs in use throughout the world and there have only been problems reported when used in ‘planes equipped with CDI units. For my part I have over 30 of them and they are now only in electric ‘planes of all different types including edfs. I have had not one problem with any of these, sorry I did have one but that was due to faulty aerials so to imply that these RXs shouldn’t be used at all is, IMO, totally unsubstantiated by any facts, unlike their behaviour with CDI units.

instead of throwing them away please send them to me where a good home awaits them.

Edited By Ron Gray on 21/04/2020 20:37:35

[Mike Blandford]

Have you ever tested with the X8R wrapped in metal foil? This was a solution for some 35MHz receivers with early electric power.

If using CDI, then it is documented that you should be using the 'PRO version of a 'X' receiver.

Mike

[stu knowles]

5G causes corona virus, the earth is flat and X8R rx's are unsafe. I believe everything I read on t'internet

[Bob Cotsford]

I'd try moving that big box marked 'voltage regulator' away from the receivers for a start. PS - all of my petrol models were CDI! I guess I was lucky!

[cymaz]

It’s good practice to socially distance the Rx/ radio side as far away from the ignition side. Batteries as well.

All my ignition stuff goes up front. The Rx and battery behind the servo tray toward the tail, assuming there’s room

[Ron Gray]

I'm like you Cymaz in where I position stuff within the fuse, unfortunately that didn't stop the X8R's waving the white flag. Doesn't seem to matter one jot in my leccy 'planes and the same RXs are rock solid in them.

[john stones 1 - Moderator]

I have X8Rs can't comment on the ignition discussion, but otherwise faultless.

[stephen kempenaers]

big Box is a "JETImodel MAX BEC 2D Plus EX"

I have run the same tests, with that "big box marked 'voltage regulator'" switched of , believe me, I tested all the possibilities. I'm not trying to dish on Frsky, I was a huge fan of FrSky, I have 10 several gas planes with CDI/magneto from 30cc to 75cc. Only 2 of them suffer from this issue. I am simply not taking the risk.

I have tested it with the Ignition kill switch removed, I tested it with a different battery pack, for the receiver and the ignition, tested it with a different spark plug, believe me, I want to be sure about my case before I post anything online!

[Frank Skilbeck]

Posted by cymaz on 22/04/2020 12:56:30:

It’s good practice to socially distance the Rx/ radio side as far away from the ignition side. Batteries as well.

All my ignition stuff goes up front. The Rx and battery behind the servo tray toward the tail, assuming there’s room

Yep, that is good practise to isolate the rx, The issue with the X8R is that if it is affected by ignition noise it can in rare instances lockout and has to be switched off and on to reboot, so if you are unfortunate enough for it to happen then even the engine stopping will not reconnect the receiver with the transmitter. So if you have an ignition model then it's probably better to use an alternate Rx.

Note the only official recommendation not to use this Rx for ignition models I could find was on the T9 website.

[flight1]

Its true for some reason that with some ignitions and quite rarely that the x8r locks out for some reason ( dosen't reset without a power cycle) and this did happen to me on 1 model but at the time i didn't know what it was.

i have the rx8 receivers in other models(more than 1) and it has been rock solid with never a issue or concern so it is a perfectly safe rx but not in some petrol ignition planes so I now use the pro version as stated to do so on petrol planes.

 

Edited By flight1 on 22/04/2020 15:46:15

[Ron Gray]

@Stephen - you are confirming / repeating what I posted at the start of this thread and was the reason for this thread and I should repeat that my original findings applied to the X range of RXs not just the X8Rs.

@Frank - no other UK supplier has put the sam earning on their websites that T9 have. As stated in my earlier posts, it was Rich who drew this to my attention after I contacted him following the loss of another 'plane. FrSky have never admitted the problem but were quick to issue a firmware update (didn't work) and brought out new RXs (the PRO) which the publicise as:

[Martyn K]

Posted by Paul Marsh on 21/04/2020 19:59:18:

The question is (also ANo order): if unsure if safe flight to go ahead then it should not do so.
I will not use those rx, and will put them in the bin now. I'm not risking it, thinking it's ok, even on an electric model, and it goes in, worse, it hits someone.

No thank you.

Whoa... Don't be too hasty

There is ONE known problem with X series receivers and that is when operating in a harsh environment with a CDi ignition unit they can lock or drop a few frames. No other problems reported. There is a fix - use the new higher spec receiver.

You cannot make a decision on whether something is fit for purpose based on one set of specific circumstances. FrSKY have done exactly the right thing to identify and report the problem.

If you assume that another set of circumstances will cause a failure - then that same risk will apply to EVERY manufacturer of radio equipment. I seem to remember lots of discussion on Spectrum failures - far, far more than have ever been reported for the X8R problem. I am sure there may be other problems with Futaba (I had a Futaba 6 channel 2.4GHz receiver that would crash and rebind) - does that mean that every Futaba 6 channel receiver should be binned?

All active Electronic devices will eventually fail. End of. Perhaps an average MTBF of 100 years or more but some fill fail sooner. In our terms, that may mean at best a lost or damaged model. If you think these infinitesimally small risks are too high then this hobby is not for you..

If you don't agree then please send me your X8Rs - I'll happily pay the postage costs.

Martyn

[Ron Gray]

Hey Martyn, stand in line in the queue!

[Mike Blandford]

While I'm aware of the X8R having a problem, as I only fly electric, I've never had any problems myself.

Since it appears the problem couldn't be fixed in software, it seems to me that electrical noise is causing one, or more, devices in the Rx to experience a hardware lockup. My question then is what is the mechanism by which this noise enters the Rx?

Three main possibilities occur to me:

1. Pickup on the antennae.
2. RF noise picked up on the circuit boards of the Rx.
3. Pickup on the external wiring (servo, battery and telemetry cables).

Not a lot to be done about (1) other than screening of the ignition cabling and increasing the distance of the antennae from the ignition circuit.

(2) May be reduced/eliminated by wrapping the Rx in metal foil (as I suggested earlier).

(3) Might be mitigated by placing ferrite rings on the cables near the Rx.

It would be interesting if these ideas could be tested to see if they improve matters or solve the problem.

NOTE that if either (2) or (3) work or improve matters then it would be a good idea to fit them on any ignition aircraft regardless of the make of the Rx in use.

Mike

[Ron Gray]

Mike, if you look back up this thread you will see a video that I did showing screening the RX using litho plate, following a suggestion from PeteC. I found that whilst it did help I still got the lockout problem when I moved the sparking plug near to the ends of the aerials, so unless they too were screened (not practical) it wasn't foolproof.

I could try the ferrite ring on the battery lead to the RX to see if that helps.

Difficult to judge point 1, the aerial distance from ignition circuit as my tests are extreme in that I bring the sparking plug into close proximity of the RX and then, obviously, the aerials. But my view is that there should be no circumstance where the RX locks out and doesn't recover!

Edited By Ron Gray on 22/04/2020 22:40:25

[stephen kempenaers]

Posted by Ron Gray on 22/04/2020 22:32:23:

Mike, if you look back up this thread you will see a video that I did showing the screening the RX using litho plate, following a suggestion from PeteC. I found that it did help but I still got the lockout problem when I moved the sparking plug near to the ends of the aerials, so unless they too were screened (not practical) it wasn't foolproof.

I could try the ferrite ring on the battery lead to the RX to see if that helps.

Difficult to judge point 1, the aerial distance from ignition circuit as my tests are extreme in that I bring the sparking plug into close proximity of the RX and then, obviously, the aerials. But my view is that there should be no circumstance where the RX locks out and doesn't recover!

I agree, the Rx shouldn't lock out, because now the CDI is the cause of the electrical noise, but there can be any other source of electrical noise, even in an electrical plane, or even an external source of electrical noise, beyond our control.

And the Rx simply doesn't recover when the noise goes away, also something I tested, shutting down the engine, so taking away the source of the electrical noise, doesn't make the Rx recover until you power it off and on again.

[Geoff Parkes]

I have just purchased a Taranis X9D plus 2019 transmitter, this is my first dip into open tx technology, as you know you dont get a battery with this transmitter, so i also purchased a 2S1P 2040ma/h Li-ion battery ( all from the very helpful Richard from T9 ) you do not get a charger either with the transmitter, you charge through the USB port ,the transmitter does have an onboard charging circuit . But does anyone own one of these new transmitters and can advise me what charger they use ? the users manual from T9 gives a spec, of Less than 5 volts @ 2.1amps via a USB adapter for a suitable charger. Many thanks .

[Andy48]

Posted by Geoff Parkes on 07/10/2020 17:13:11:

I have just purchased a Taranis X9D plus 2019 transmitter, this is my first dip into open tx technology, as you know you dont get a battery with this transmitter, so i also purchased a 2S1P 2040ma/h Li-ion battery ( all from the very helpful Richard from T9 ) you do not get a charger either with the transmitter, you charge through the USB port ,the transmitter does have an onboard charging circuit . But does anyone own one of these new transmitters and can advise me what charger they use ? the users manual from T9 gives a spec, of Less than 5 volts @ 2.1amps via a USB adapter for a suitable charger. Many thanks .

I would start a new topic with your post. This will likely get lost in the system.

[Kim Taylor]

I've got one of these and I either just plug the USB plug into the port in my computer, use the charger which I got with my smart phone, or straight into the USB socket built in to the 240v wall outlet indoors.

Never had an issue with any of the above, although the computer did get a slightly warm.

Kim

[GrumpyGnome]

I too have used a pc, mains usb socket with no issues. However, my lipo is often poorly balanced so every few weeks i take the lipo out and use my flight battery charger. Not sure if this is an issue with the Taranis charge circuitry or my lipo....

GG

[Ron Gray]

Agree with Andy48, to get a better response create a new thread, but in response to your question, I've been using my Taranis X9D 2019 since, well 2019, and have only ever charged it via the USB port and haven't had any issues. Now that is tempting fate!

Just went out and checked the battery, 4.087 and 4.089, so not too bad.

Edited By Ron Gray on 08/10/2020 08:21:47

[Geoff Parkes]

Sorry guys for jumping into this topic, as soon as i posted my reply i realised that i should have initiated a new topic, will do now ,but thanks for the replies, as usual there is someone out there prepared to offer help, regards Geoff.