Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[mick8488]

Hi gents,

Need to get some advice.
I recently took delivery of my ZTW 10A UBEC that has switchable voltages between 5v, 5.5v and 6v. I am running an FR Sky XR8 receiver.
I subsequently plugged the ZTW into channel 8 on my receiver and plugged in my small 2s pack. Voltage was set to 5.5v on the ZTW UBEC. It all seemed to be operating fine, I did a check by unplugging the two main 6s packs and I still had power to the control surfaces so all good.
However, I noticed the ZTW was getting quite hot. So I switched it off and unplugged it. I then attempted to power up the mig using the supplied ubec (the normal way) and it would now no longer arm. There was no red light on the supplied UBEC either. So I plugged back in the ZTW, now set to 5V and everything armed, and the supplied UBEC's red light came back on.
So now I'm thinking I've shorted something either on the supplied UBEC or the receiver so I plug the supplied UBEC into another receiver and it powers up no problem with the red light on.
It's the weirdest thing.
Can anyone explain what may be happening as I'm at a loss. I don't think the supplied UBEC is damaged as it still works, but not through the FR Sky receiver.

[Firebird]

Hello to the forum!

I‘m from germany and just received my Mig29. I read all of the posts while waiting for the delivery. As there is obviously a issue with the elevator response, started to disassemble the aircraft, searching for a possible reason for the crashes. When i opened the compartment holding the fan and the motor controller, i found both - elevator and rudder servolines - passing freely, directly underneath the controller. I‘m not a electronic expert but i do suspect the motor controller to create a certain electromagnetic noise at midrange powersetting. As the servolines (which might in my opinion be a bit to weak in diameter anyway for the length of the cables) are laying free under the controller, in some aircrafts they might be further away from the disturbing signal as in others. A possibility already weak signal (Signal line) coming from some receivers might be overpower by the electromagnetic noise of the controller. Right ruder and elevator pass underknees right controller, left servolines underkness the left one. At a certain powersetting both controllers might block the servoslines on there side which might not only block the elevator - it might also block the rudder. Basically all tail servos. That would explain that cutting the power might help to regain control- because the disturbance stops. It explains as well the the servos work again after the crashes. And it explains that the user using jeti telemetrie did record no voltage drop in the rc system during the event - because the power is there - just the servo signal lines get blocked. As i said before - i‘m not a expert. But i will reroute my (upgraded) servo lines away from the controllers and power lines before maiden. I hope this information might be helpful in finding the problem.

Happy landings!

[Evan D]

I agree with your thought process. I pulled those extensions out and put in shorter and larger gauge ones since I moved my MCBe to the rear of the battery area. I also plugged each servo/ surface into it's own slot on a 12ch rcvr. I did not add any chokes to the wiring but that may help too.

[AirHead]

Hello to the forum!

I‘m from germany and just received my Mig29. I read all of the posts while waiting for the delivery. As there is obviously a issue with the elevator response, started to disassemble the aircraft, searching for a possible reason for the crashes. When i opened the compartment holding the fan and the motor controller, i found both - elevator and rudder servolines - passing freely, directly underneath the controller. I‘m not a electronic expert but i do suspect the motor controller to create a certain electromagnetic noise at midrange powersetting. As the servolines (which might in my opinion be a bit to weak in diameter anyway for the length of the cables) are laying free under the controller, in some aircrafts they might be further away from the disturbing signal as in others. A possibility already weak signal (Signal line) coming from some receivers might be overpower by the electromagnetic noise of the controller. Right ruder and elevator pass underknees right controller, left servolines underkness the left one. At a certain powersetting both controllers might block the servoslines on there side which might not only block the elevator - it might also block the rudder. Basically all tail servos. That would explain that cutting the power might help to regain control- because the disturbance stops. It explains as well the the servos work again after the crashes. And it explains that the user using jeti telemetrie did record no voltage drop in the rc system during the event - because the power is there - just the servo signal lines get blocked. As i said before - i‘m not a expert. But i will reroute my (upgraded) servo lines away from the controllers and power lines before maiden. I hope this information might be helpful in finding the problem.

Happy landings!

Take a piece of aluminum foil and crumple it up to give it some texture. Then, stretch it out a bit and cut a piece as wide as the speed controller and wrap it around once and tape it on. This will create an electronic shield to some degree and a free heat sink at the same time...Who knows, it might help...

[kallend]

Hi gents,

Need to get some advice.
I recently took delivery of my ZTW 10A UBEC that has switchable voltages between 5v, 5.5v and 6v. I am running an FR Sky XR8 receiver.
I subsequently plugged the ZTW into channel 8 on my receiver and plugged in my small 2s pack. . . . . .

Plugged the 2S pack into what?

[kallend]

Take a piece of aluminum foil and crumple it up to give it some texture. Then, stretch it out a bit and cut a piece as wide as the speed controller and wrap it around once and tape it on. This will create an electronic shield to some degree and a free heat sink at the same time...Who knows, it might help...

Aluminum foil wrapped around the speed controller will not shield against magnetic fields from the power wires.

[Simjet-uk]

I chalked up another four flights yesterday, no problems whatsoever. Have to say though that it has taken a while to relax with this plane, not for any reason other than reading these 'there's something wrong with this plane and it will probably crash' posts. I expect that sales of this beautiful plane are in the high hundreds or thousands (I have no idea how many they actually have sold) but the crashes are what? around 10?
If hundreds of people make a plane, some will crash it, either due to bad setup or bad luck. Maybe we should stop trying to identify the mystery and just enjoy the way it looks and flies?



This is mine rolling into knife-edge flight.

[Simjet-uk]

Another one, just so mean looking!!

[Evan D]

"bad setup or bad luck"... I think the first few crashes on video where just dumb set ups and not reading the instructions. Putting the push rod in the servo's outer hole and placing batteries in the front and aft battery spots not realizing there is a middle spot and then flying it very nose heavy. While I think many new owners are now aware of these pitfalls we have to remember that the people reading these forums are a small percentage of the buyers and even those that buy from Motion and got the servo email are a small percentage.

I chalked up another four flights yesterday, no problems whatsoever. Have to say though that it has taken a while to relax with this plane, not for any reason other than reading these 'there's something wrong with this plane and it will probably crash' posts. I expect that sales of this beautiful plane are in the high hundreds or thousands (I have no idea how many they actually have sold) but the crashes are what? around 10?
If hundreds of people make a plane, some will crash it, either due to bad setup or bad luck. Maybe we should stop trying to identify the mystery and just enjoy the way it looks and flies?



This is mine rolling into knife-edge flight.

[PieterO]

Another one, just so mean looking!!

Great picture! Wow!

[AirHead]

Aluminum foil wrapped around the speed controller will not shield against magnetic fields from the power wires.

Right...Foil shielding is used mostly for RF and Common Mode Noise. I thought it might have some effect between the controller and the servo wiring, but big DC EMF is unavoidable...The modern world was invented using aluminum foil and Scotch tape, so I thought I'd throw that in there....Nevermind....

[Airguardian]

As there is obviously a issue with the elevator response, started to disassemble the aircraft, searching for a possible reason for the crashes. When i opened the compartment holding the fan and the motor controller, i found both - elevator and rudder servolines - passing freely, directly underneath the controller. I‘m not a electronic expert but i do suspect the motor controller to create a certain electromagnetic noise at midrange powersetting. As the servolines (which might in my opinion be a bit to weak in diameter anyway for the length of the cables) are laying free under the controller, in some aircrafts they might be further away from the disturbing signal as in others. A possibility already weak signal (Signal line) coming from some receivers might be overpower by the electromagnetic noise of the controller. Right ruder and elevator pass underknees right controller, left servolines underkness the left one. At a certain powersetting both controllers might block the servoslines on there side which might not only block the elevator - it might also block the rudder. Basically all tail servos. That would explain that cutting the power might help to regain control- because the disturbance stops. It explains as well the the servos work again after the crashes. And it explains that the user using jeti telemetrie did record no voltage drop in the rc system during the event - because the power is there - just the servo signal lines get blocked. As i said before - i‘m not a expert. But i will reroute my (upgraded) servo lines away from the controllers and power lines before maiden. I hope this information might be helpful in finding the problem.

You may be onto something there!

[xviper]

Hi gents,

Need to get some advice.
I recently took delivery of my ZTW 10A UBEC that has switchable voltages between 5v, 5.5v and 6v. I am running an FR Sky XR8 receiver.
I subsequently plugged the ZTW into channel 8 on my receiver and plugged in my small 2s pack. Voltage was set to 5.5v on the ZTW UBEC. It all seemed to be operating fine, I did a check by unplugging the two main 6s packs and I still had power to the control surfaces so all good.
However, I noticed the ZTW was getting quite hot. So I switched it off and unplugged it. I then attempted to power up the mig using the supplied ubec (the normal way) and it would now no longer arm. There was no red light on the supplied UBEC either. So I plugged back in the ZTW, now set to 5V and everything armed, and the supplied UBEC's red light came back on.
So now I'm thinking I've shorted something either on the supplied UBEC or the receiver so I plug the supplied UBEC into another receiver and it powers up no problem with the red light on.
It's the weirdest thing.
Can anyone explain what may be happening as I'm at a loss. I don't think the supplied UBEC is damaged as it still works, but not through the FR Sky receiver.

Can't quite understand from your explanation if you are using BOTH the stock BEC and your ZTW BEC at the same time. If you are, that might be the problem.

[janmb]

Hello to the forum!

I‘m from germany and just received my Mig29. I read all of the posts while waiting for the delivery. As there is obviously a issue with the elevator response, started to disassemble the aircraft, searching for a possible reason for the crashes. When i opened the compartment holding the fan and the motor controller, i found both - elevator and rudder servolines - passing freely, directly underneath the controller. I‘m not a electronic expert but i do suspect the motor controller to create a certain electromagnetic noise at midrange powersetting. As the servolines (which might in my opinion be a bit to weak in diameter anyway for the length of the cables) are laying free under the controller, in some aircrafts they might be further away from the disturbing signal as in others. A possibility already weak signal (Signal line) coming from some receivers might be overpower by the electromagnetic noise of the controller. Right ruder and elevator pass underknees right controller, left servolines underkness the left one. At a certain powersetting both controllers might block the servoslines on there side which might not only block the elevator - it might also block the rudder. Basically all tail servos. That would explain that cutting the power might help to regain control- because the disturbance stops. It explains as well the the servos work again after the crashes. And it explains that the user using jeti telemetrie did record no voltage drop in the rc system during the event - because the power is there - just the servo signal lines get blocked. As i said before - i‘m not a expert. But i will reroute my (upgraded) servo lines away from the controllers and power lines before maiden. I hope this information might be helpful in finding the problem.

Happy landings!

This is indeed a highly interesting finding, and may very well be 100% spot on. It does indeed fit the observed failure mode pretty damn perfectly.

Not necessarily very easy to mitigate either, but now that we know to deal with it, at least some effort can be made to alleviate that risk.

Thanks for the analysis, sounds highly plausible and will definitely take it into account.



What kinda bothers me though, is that we hear all this talk about how every model is put through several hundred test flights during the development phase. Well, if that is indeed the case, then I find it quite peculiar that any conceptual problems like this one doesn't rear its ugly head enough for the developers to catch it. Sure, it may happen just once every 50 or 100 flights, or even less, but still, with multiple prototypes being flown for hundreds of flights, the chances of such a failure manifesting itself should be fairly high.

[kallend]

I chalked up another four flights yesterday, no problems whatsoever. Have to say though that it has taken a while to relax with this plane, not for any reason other than reading these 'there's something wrong with this plane and it will probably crash' posts. I expect that sales of this beautiful plane are in the high hundreds or thousands (I have no idea how many they actually have sold) but the crashes are what? around 10?
If hundreds of people make a plane, some will crash it, either due to bad setup or bad luck. Maybe we should stop trying to identify the mystery and just enjoy the way it looks and flies?



This is mine rolling into knife-edge flight.

Thousands of successful flights were made on Boeing 737 MAXes and only 2 crashed. Only 0.03% of Ford Pintos incinerated their occupants. Only one DC-10 (out of 386 made) crashed (346 fatalities) due to the faulty design of its cargo door.

[GliderGuy]

Hello to the forum!

But i will reroute my (upgraded) servo lines away from the controllers and power lines before maiden. I hope this information might be helpful in finding the problem.

Interesting....now you’ve got me considering a re-route back there even though I haven’t had issues to date. Seems like an easy thing to do for even more safety margin.

OR....even easier / Remove each servo and install a clip-on small RF choke on each of the servo’s wires. This won’t impact CG because the chokes are light weight, and there is plenty of room back there for one of the small chokes.

https://www.amazon.com/Cedmon-Pieces-Ferrite-Suppressor-Diameter/dp/B07CWCSNW9/ref=sr_1_4?keywords=rf+chokes&qid=1578870654&sr=8-4

-GG

[JohnVH]

Super crosswind flight, with Gooniac Afterburner!

[RudyD54]

For anyone who does what I did and accidentally snaps off the pitot tube in front and needs a new one, the part is the following:

https://www.motionrc.com/products/freewing-80mm-edf-mig-29-nose-cone-part

The MiG-29 parts pictures aren't up yet and when I called support they said it came with the nose cone (it does not) and had no idea what "Plastic Nose Cone Part" referred to. I placed an order for both parts which are luckily priced reasonably. The nose cone comes with ONLY the nose cone and the wood piece you glue into it. Plastic nose cone part includes everything attached for 4.49.

[leithalweapon]

I think the guy from Germany just solved the problem. Why the hell would they run signal wires up against the esc. Highest level of engineering my arse!
Alpha, oh no you didn't

Luckily I have copper foil tape.

[Bushong572]

For anyone who does what I did and accidentally snaps off the pitot tube in front and needs a new one, the part is the following:

https://www.motionrc.com/products/freewing-80mm-edf-mig-29-nose-cone-part

The MiG-29 parts pictures aren't up yet and when I called support they said it came with the nose cone (it does not) and had no idea what "Plastic Nose Cone Part" referred to. I placed an order for both parts which are luckily priced reasonably. The nose cone comes with ONLY the nose cone and the wood piece you glue into it. Plastic nose cone part includes everything attached for 4.49.

Thanks, I was looking for this part ( I broke mine also)