Can a ECU going bad effect the radio
 

I have a BVM Cougar with a King Tec 120 that has 80 flights on it and never had a radio problem. I fly futaba and have 2 receivers in it. This was done to get enough channels. I was at Jets over the heartland and decided to fly it. When I taxied out and it was about 100 ft from me the flaps and ailerons started jumping around. I shut off the gyro but it did not make a difference . When I got home I started it up and was going to taxi it around to see if I could duplicate the problem. The engine would accelerate to about half throttle and die. When it was cooling down it would get to 100 degrees then the starter keeps running. The only way to stop it was to disconnect the power to the ECU. I got on the phone with Barry and we determined that the ECU went bad. Today I installed the new ECU and it ran perfect . I taxied it around and got it at least 150 ft from me and the controls were stable. After the taxi test I replaced both receivers just to be safe. My question is has any one else had a ECU effect the radio? The only thing I can think of if a component in ECU was shorting on the rx side maybe it was causing a power fluctuation . I did not have my fail safe set up right so it would not turn off the turbine

Dan,

I have not had that problem before, but it certainly is possible. The servo signal wire(s) are a bus. Normally, there's only one writer of the bus (the receiver or Powerbox, etc.) and everyone else, like servos, is a reader. Even in the newer busses like Sbus2, that are "bi-directional" for telemetry sensors, the main writer is the same, just that the telemetry sensor(s) can also write on the bus so that they can send their info to the telemetry TX in the receiver.

The bottom line is, everyone on the bus must "behave" correctly - not only with the protocol, but also electrically (like releasing the bus when they aren't using it). If an ECU, which is a bus reader, is failing, it could easily be either putting junk on the bus, or "hanging it" garbling what others are trying to send on the bus.

Its doubtful that a bad ECU could be causing electrical noise that is affecting the 2.4GHz TX to RX link. Back in the 72 MHz days, that could easily be a problem, but at 2.4 GHz, I doubt that's the problem.

If you still have the bad ECU, it might be interesting to setup a single receiver with some servos, get it operating correctly, and then plug in the bad ECU and see what happens...

Bob

Bob I had to send it in to King Tec so they can program it with the time. They kept it. When I was trying to get the engine started I used another RX and still could not get the engine to go over half throttle.

I would say its entirely possible. not turbine related, but i have had many people tell me 2.4ghz is "impervious" to RF interference from gasoline engines. But yet i have had 2 models that suffered interference issues when their electronic ignition module went bad. Surfaces started working erradic on their own.

I've had my issues with Dirk and Barry and as a result, I no longer use ANY KingTech engines.

YMMV but that's my experience.......

Hello together,

ECU interference and ESD problems can happen from time to time. Below you will find a link to a white paper wich I have published in 2019.

Turbine related - CB Elektronics (cb-elektronics.com)
Look for the PDF white paper on the above link.

If you have any further questions don not hesitate to contact me.

BR
Dirk CB Elektronics

You can also use fibre optic encoders/decodes to decouple any physical electronic signal connections. Long time ago started to use them on large scale RC when you had 10+ ft of servo wire, you would have + - and a long fibre optic signal wire.

Also use them on UAS projects.

You can see them today all over the place mainly in gas kill switches which isolates the RC from the ignition system.

Regards,

The question was has any one had the same problem. I have been flying Jets for over 20 years and never seen this. It might not be the ECU. I do use fiber optic kills on my 3d planes.

My comment was based on the previous post regarding galvanic isolation which didn't address your question either.

Regards,

Never had any problem or seen problem like you described….but I guess it’s possible for any piece of electronic to develop defect after a while….

Hello Dan ! It's been a long time since we hanged together.

I have had my share of bad ecu's, including one getting on fire while in the air. So far none has affected the radio link.
I think you had two non related problems.
I wouldn't be satisfied with the ecu's interference as a cause ... I would rather look for a radio issue. Surfaces jumping around are weird.
If you hadn't said that the flaps were also jumping, I would say it's the gyro (it doesn't make any difference if you turn it off), but I presume that they are not connected to the gyro.
Telemetry would tell you what happened .....

Hope to see you again soon !

Jack

Jack hope all is well. I did replace the 2 both rxs I was planning on going to Waco jets but the fell and broke 7 ribs

Wow Dan, that's too bad! I wish you a quick recovery!

Bob Klenke

Dan
Sorry to hear that .... you must be in heavy pain .
Motorcycle ??
Taking laxatives makes number 2 less painful .... (latin technology :))

Hope you recover soon.

Jack

Sorry to hear, Dan. Hope you heal quickly and without too much pain.

I was in bed and had a bad dream. Jumped up and must have hit the night stand. In a trama center in phoenix for about a week . Thanks for the good thoughts

Got my best wishes. As a retired Paramedic/Firefighter, i can tell you that spending any time in the hospital is no fun, especially anything above the general population. Those folks in the Trauma Centers, Surgical Centers, ICU's and such just do no have an sense of humor nor inclination to let the rules slide even a bit. These are things I l learned after having to spend some time in each of those settings..

Hope they will at least keep you doped up for the rib pain and wishing you the best.....

So far so good I’ll get me a Starbucks coffee now so that’ll be pretty cool service just have one guy that’s an attentive hopefully I can get out of here next within a week thanks

Hi Dan, Hope you feel better.. I have seen only one ECU issue that we traced down to interference and it was when a spectrum receiver satellite was mounted right next to an old brushed fuel pump. it was creating noise..

However if the ECU was shorting out, it could cause power fluctuations on the line, and I suppose its possible some signal noice, but ECUs are designed not to feed rpm noise back thru signal. I think it was smart to replace receivers, but I would evaluate your positions of the whiskers to make sure none if them are too close to the turbine components.. I would then on your range check, walk until the turbine shuts down to raise your confidence in the link during range check..

I chased one down also for Ron back in the day that had the smoke pump near the receiver.. there is kind of a basic rule of thumb not to mount the ecu near the main receiver

Oh.. Im back from my 3 year sabbatical in the hobby.

Goose it was good seeing you in Winamac my thinking was power fluctuations more than sign. I replaced both rxs and the ecu and inspected everything. When we used to be on 72 mg I had servo causing fail safe. So maybe the ecu was shorting. Or something else that will crash the plane Will find out when I get healthy enough to fly it. Thanks Dan PS made it home from the hospital yesterday