CTSW flap problems on final

[GlennM]

Where in Sweden are you?  

[swedishCT]

Enköping

[GlennM]

Nice.  I have visited Finspång for work.  Beautiful country, even though the weather was cold and rainy when I was there.

[cdarza]

On 2/10/2023 at 3:42 AM, Anticept said:

Between all that and the numerous potentiometer failures, I really want to redo the flap system. An American made actuator, and a proper potentiometer that is built to tolerate vibration or even a non-contact potentiometer. The pots keep going bad with dead spots in them.

If you ever come up with workable replacement please lemme know.     Trouble shooting a failed flap right now and wished it was alot simpler especially for clueless people like me.    

[Towner]

11 minutes ago, cdarza said:

If you ever come up with workable replacement please lemme know.     Trouble shooting a failed flap right now and wished it was alot simpler especially for clueless people like me.    

X2

[cdarza]

I think i got lucky today.   Not the Pot,  not the micro switches and more importantly not the board.  My mechanic found a lose (disconnected) wire from behind the flap switch (it had a label "UP").    Reconnected and all good. 

My flap issue was the flaps would not retract after takeoff from the 15 degree setting.  Went to 30 and 40 but would not go back up. 

 I usually cycle the flaps up and down as a pre-take off check but not on this day (#&*!)      

[Roger Lee]

This is why I tell everyone with flap issues to always push and twist all bullet connectors right behind the panel before they do anything else. I have seen many fix their flap issue just by doing this.

[Towner]

Recently, my 40 degree flap setting is not working at all. If I go to manual, I can get 40 degrees. Is this most likely a wiring or circuit board issue?

[Anticept]

Does the panel blink while 40 is selected?

[Towner]

2 hours ago, Anticept said:

Does the panel blink while 40 is selected?

I don’t remember. I’ll have to check.

[Roger Lee]

Sometimes just reprogramming the flaps works. I've reprogrammed several and they were fine after that.

[FlyingMonkey]

I'm just seeing this thread.  A couple of years ago Roger and I had a conversation about how sometimes my flaps seem more sluggish than other times, and I usually cycle them before taxi which seems to "warm them up" and get them working better.  We talked about the possibility of drilling into the case of the actuator in order to provide a hole for lubrication without disassembly.

I did this, and as far as I know I'm the only one who has.  You make a small hole in the case, using one of the pics online of the internal guts here for reference and drilling slowly, to make sure you don't drill into one of the fine gears inside.  Once you have a hole you can periodically squirt your lube of choice (I use Inox MX-3) into the hole to make sure things stay slippery in there.  I do this during my annual, and so far I'd say it has increased my flaps speed in most conditions marginally.  This was a true experiment, so only do this if you are E-LSA and willing to risk having to replace the actuator, and only if you have exhausted other options to keep your flaps running smoothly.

When not being used for lube, I cover the hole with a velcro cable strap around the actuator body.

[Anticept]

The actuator portion can be accessed by removing one of the screws that go into the side of the jackscrew tube. It's what the actuator pivots on. It will expose the jackscrew.

The motor gearbox is covered by a black push plug. Pop that out and you can spray in there too.

[Towner]

On 4/27/2023 at 12:10 PM, Anticept said:

Does the panel blink while 40 is selected?

Shows three dashed lines

[Anticept]

That means your rotary switch on the board has gone bad. The microcontroller is unable to determine what flap setting is being requested.

As additional evidence: When you set manual up or down, there are no connections to the microcontroller and that is why it shows three dashed lines. Instead, manual up bypasses the microcontroller completely, sending the signal to the relay itself. At that point, the microswitches on the actuator are the last resort to stop the movement by opening the signal connection to the relays.

Are you E-LSA?

[Towner]

10 hours ago, Anticept said:

That means your rotary switch on the board has gone bad. The microcontroller is unable to determine what flap setting is being requested.

As additional evidence: When you set manual up or down, there are no connections to the microcontroller and that is why it shows three dashed lines. Instead, manual up bypasses the microcontroller completely, sending the signal to the relay itself. At that point, the microswitches on the actuator are the last resort to stop the movement by opening the signal connection to the relays.

Are you E-LSA?

Is the the case if only the 40 degree setting seems to be affected? I’m am still S-LSA.

[Anticept]

It's going to be very, very expensive for you then unless you can get an MRA to replace components on the board.

The rotary switch is a very common profile and many manufacturers make it.

Yes it is the case. The rotary switch has segmented contacts in it. It's possible you might just need to do a reflow to repair it.

[Towner]

11 hours ago, Anticept said:

It's going to be very, very expensive for you then unless you can get an MRA to replace components on the board.

The rotary switch is a very common profile and many manufacturers make it.

Yes it is the case. The rotary switch has segmented contacts in it. It's possible you might just need to do a reflow to repair it.

Thanks

[CTSW Bob]

Might be worth a try….

I have restored several old cars.  Electronics can be stubborn, but I have fixed a lot of gremlins with electrical contact cleaner.  Remove power from the switch, spray liberally, then let dry.  I have a more than 50% success rate by far.  Worth a shot, IMHO.  
 

Other than that, as stated earlier, source a new rotary knob and break out the desolder and solder equipment.  I new switch and shipping should be under $20.

Bob

[Anticept]

The desoldering irons are the best things since sliced bread for stuff like this.

[Towner]

I’m not good with electronics, but getting better! Thankfully, I have a buddy that works with electronics all day! I’ll have to pull it out, but he’ll make a repair if possible. 
 

Any idea of what knob will work so I can get it ordered?

[Anticept]

If he's an EE, he'll be able to figure it out extremely easily.

Pass this along:

There is a manual up position in the most counter clockwise direction, and manual down position in the most clockwise direction. These bypass the microcontroller completely. In between, there are 5 sensed positions by the microcontroller. (Towner, this should be 7 positions total, but there are some CTs that only have 6. If you do not have 7 positions let me know what position you don't have).

The microcontroller expects either a 5k or 10k potentiometer hookup in a voltage divider configuration.

Three more wires provide a common and 2 signals for regulating the up and down function of relays which supply power to the motor. The relay board is separate on this unit and is configured in a way that both up and down relays cannot be engaged at the same time.

He shouldn't need to power it up to swap the rotary switch or even test it to verify if it's the rotary that's malfunctioning (it's remotely possible that there is damage to another board component). This isn't a multi-layer PCB, but there are traces underneath the rotary that obscure which pads are connected to what, and the way the board is laid out makes it relatively easy to probe and determine where the rotary settings go without having to desolder anything or power it up. However, if the rotary IS NOT bad, then this just got a lot more complicated.

I repaired mine years ago with the blessing of FDUSA. A shop got the autopilot and dynon EFIS connectors reversed which blew out a lot of my avionics including flaps. I didn't notice the flaps were not operating until after everything was settled. What it ended up being was a fried darlington transistor array. 58c later + shipping, and a 200 dollar SMD rework station, and it was repaired and ready to go.

I don't pretend to be EE level, it was luck that i even found the array was fried, I was taking shots in the dark on where to probe based only on data sheets of individual components, I would have had to do some serious desoldering to be able to map the traces. But, at the time, replacements for the board didn't exist anymore and I really did NOT want to deal with the extreme cost of the new version of the flaps, which also would have required drilling holes to run new harnesses.

I very much prefer the old style with the separate relay control. The old version makes it very compatible with using any kind of flap control, all it has to do is send a switching signal for the relays and it doesn't matter what the controller itself is. It's on my list of "fun projects to experiment with" to take an arduino and program it to act as a replacement to the flap position microcontroller board.

[Towner]

It sure seems like one of the most common issues with CT’s. I’d love to see you make a better design and get it approved by Flight Design. I know it’s probably just wishful thinking, but we all can dream!

As always, thanks for the detail. We both appreciate it!

[Vic]

On 2/11/2023 at 1:48 PM, FredG said:

On January 17, 2022, I posted several photos of a disassembled CTsw linear actuator and described the procedure I used to disassemble and reassemble it.  My flaps actuator was slow and made a loud grinding noise in cold weather.  After disassembly, cleaning and lubrication, it works like new.  BTW, if you look at the photos I posted, you will see that it is not possible to spray lubricant on any external part of the linear actuator and expect that lubricant to reach the speed reduction gears nor the lead screw (jack screw) that moves the actuator shaft.  

Similarly to what Corey wrote, I deploy flaps at slower speeds than the maximum permitted by FD.  This puts less load on the linear actuator.  

I have also had two relay board failures on my plane (2006 CTsw with over 4000 landings).  Overall, in my opinion, the flap actuation system is overly complicated and too reliant on proprietary electronics.  When it works, it's very pilot friendly.  But, between unreliable electronics and a temperamental linear actuator (which is a PIA to access), the system leaves something to be desired.  

I tried looking for this thread in all the Flap discussions.  Can someone find the link for this.  Id like to look at the pictures FredG took.

[Jim Meade]

Slow Flaps Cycling

If that doesn't work, go to the member list, find FredG and search under content.  Second page using that method.