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Slow Flaps Cycling


FlyingMonkey

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10 hours ago, FlyingMonkey said:

cdarza, thanks for the great photos!  You reference a white plastic part not in your photos...can you shoot a pic of it an where it goes in the assembly?

I edited my previous post and included picture of the plastic pc - and indicated where that fits    :)

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Has anyone tried removing the whole actuator? It looks like the cleaning would be easier.,  However, the service manual does not address this. seems to be mounted with two studs in brass pivots, and tip of lead screw. Plus the limit switches and pot assembly. re-assembly is probably two persons to move flaps to place bolts.

I think I would risk having to re-adjust the limit switches, and the angle sensor (pot). I wonder about risk and reward of doing it that way.

i have the switches to set the flap angle in the controller.

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On 12/2/2019 at 9:06 PM, Aaronp07 said:

The exact same thing happens to my 2009 CTLS, exatly as you described it. Happens almost every time on the first flap movement of the day on the ground. I have also tried the Inox with no success. I have been perplexed for months. Ill keep an eye on this thread. If you find anything out please let me know, and I will do the same. 

Will do.

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  • 3 weeks later...

Thank you, Corey and cdarza !!

Had a slow & uneven flaps actuation (see video).

Inspired by Corey's description and cdarza's photos, I leapt in and dismantled, cleaned and re-greased the Flaps Actuator in our CT2k.

Much smoother action now.

Thank you again for generously sharing this knowledge.

David

Australia

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  • 2 weeks later...

UPDATE :

After cleaning and greasing with Moly, the Flaps behaved much better - for a short while - then, just as bad as before !

Removed the motor/gearbox again, and observed that even a tiny glob of the new Moly grease going through the gears, caused the motor to labour.

Cleaned the gearbox out and put some Shell Advance VSX4 oil in it (there is a gasket between the electric motor and the gearbox) leaving the Moly on the jack-screw and bearing-races.

After several flights and much Flaps cycling, all now working perfectly.

David

 

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On 2/19/2020 at 6:36 PM, BMcCand - N248CT said:

Has anyone tried removing the whole actuator? It looks like the cleaning would be easier.,  However, the service manual does not address this. seems to be mounted with two studs in brass pivots, and tip of lead screw. Plus the limit switches and pot assembly. re-assembly is probably two persons to move flaps to place bolts.

I think I would risk having to re-adjust the limit switches, and the angle sensor (pot). I wonder about risk and reward of doing it that way.

i have the switches to set the flap angle in the controller.

well, replying to myself!  I did try to remove the actuator, but could not loosen all 4 screws on the left side of the mount. This is behind the aileron trim lever. I used the way of removing the motor 4 screws . dissassembly, greasing was easy. However, getting the bearing into the proper position to place the white plastic rotation lock was challenging. finally rigged the inspection camera to look, got pin pliers into the two holes to rotate bearing. took 2 days, including dropping white piece.. even with a towel 

Happy to report flaps work well now, will actually get down to 40 deg at 60 kt.

 

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Corey thanks for the advice.  Cdarza and David, excellent photos and commentary.  Does it appear that the drag is being caused by lack of lubrication to the jack screw assembly or is it being caused by poor lubrication of the ball bearing area? If jack screw is the culprit, is there a seal on the screw preventing getting grease into it?  Is there a way to force lubrication and work this into the jack screw and activator by running up and down while working grease into it without tear down?

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On 3/28/2020 at 2:36 AM, Runtoeat said:

Corey thanks for the advice.  Cdarza and David, excellent photos and commentary.  Does it appear that the drag is being caused by lack of lubrication to the jack screw assembly or is it being caused by poor lubrication of the ball bearing area? If jack screw is the culprit, is there a seal on the screw preventing getting grease into it?  Is there a way to force lubrication and work this into the jack screw and activator by running up and down while working grease into it without tear down?

Hi Dick.

I just took Corey's advice and re-greased the Jack-Screw.

The grease that I cleaned off the Jack-Screw and around the Gearbox was, in places, quite hardened and so wouldn't have been much good for smoothing the action.

The re-greased Jack-Screw certainly screws in and out much easier (when twirling by fingers to extract it and re-insert it) than before - I did feel some binding on the Jack-Screw initially, but this seems to have been overcome by the new grease and the oil in the gearbox.

The hardest bit of the process was being a contortionist doing it all through the Luggage-Door.

Cheers,

David

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On 3/28/2020 at 2:50 AM, FlyingMonkey said:

I'm working on an alternate solution to this problem, will let you guys know how it works out.

Hi Andy,

I tried ADE-WERK GmbH for a replacement actuator .. they directed me to their 'distributor' for this part: Flight Design, Germany (no response from them yet).

I did see a bunch of 150mm linear actuators on eBay - cheap-as-chips ..

David

IMG_1809.jpg

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On 3/25/2020 at 2:22 AM, BMcCand - N248CT said:

well, replying to myself!  I did try to remove the actuator, but could not loosen all 4 screws on the left side of the mount. This is behind the aileron trim lever. I used the way of removing the motor 4 screws . dissassembly, greasing was easy. However, getting the bearing into the proper position to place the white plastic rotation lock was challenging. finally rigged the inspection camera to look, got pin pliers into the two holes to rotate bearing. took 2 days, including dropping white piece.. even with a towel 

Happy to report flaps work well now, will actually get down to 40 deg at 60 kt.

 

Good persistence, Bill !

8-)

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  • 5 months later...

How much force/pressure would you estimate the flaps/motor have when you go from example; 0 degrees to 15degrees etc etc ... I ask as i am trying to still trouble shoot my flaps cycling and i did try to place force on the flaps (a lot) and the flaps cycled very nicely even with audible strain on the motor... when in the air at 80kts and less -even down to 60kts the flaps will come down from 0 to 15 in multiple steps ... not one fluid motion.  I regreased for the second time recently the jack screw etc etc again today - will try a test flight but am expecting same results :(

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  • 1 year later...

My airplane is a 2006 CTsw.  My flap actuator unit (linear actuator) was making a grinding noise in cold weather.  So, I decided to fully rebuild the unit.  What follows is my description of the full disassembly and reassembly.  This is my process.  I have no idea whether is it correct for your airplane nor whether you have the ability to perform the rebuild.  Consider this post to be for your entertainment only.  I am not responsible for anything you do to you airplane.  Also, my airplane has Experimental registration and I am, consequently, permitted to perform maintenance on it.  

First, in this description, I will call the larger black anodized tube (that remains stationary during flap movement) the "outer tube" and the smaller diameter tube (that moves during flap movement) the "inner tube" (see photo).  The cast lead screw gear housing will be called the "cast housing."

The photo of parts on the yellow pad includes all parts except the two pivot screws that attach to the external holes on the large collar at the bottom of the outer tube (in addition to serving as a pivot, they also secure the cast housing to the base of the outer tube).  The parts depicted on the yellow pad are NOT in any special order and should be used solely to see what each part looks like and not as a guide to the order of assembly.  As noted by Corey in an earlier post, the order of the parts is critical (and their orientation matters, since there are four spring washers (conical or belville washers), the larger two of which are located between the cast housing the base of the outer tube into which it inserts and the other two of which provide preload to the ball bearings).  The two larger spring washers are oriented such that their outer edges are in contact (and so that they form a shape like a flying saucer).

There are a couple of steps during disassembly that must be done with proper tools and technique or the parts will be damaged. My first step was to remove the entire unit from the airplane.  It is a very tight fit to remove when all of the flap regulator parts are attached (the assembly with microswitches, potentiometer, etc).  As mentioned by Corey, I put the flaps in the lowest position and then used duct tape on the flaps/wings to prevent additional downward movement when the actuator was removed.  I had to remove the interior light from the bulkhead between the cabin and the baggage compartment to make room.  If you can disconnect the wires to the flap actuator that will help.  On my airplane the wires to the flap regulator mechanism had no nine-pin connector (later airplanes have this convenient connector) and so after removing the linear actuator from the flap mechanism, I removed all those parts and left them, wires attached, in the baggage compartment.  

Removing the actuator requires removing the bolt from the upper pivot and keeping track of the brass bushing in the top eyelet of the actuator.  If the top of the actuator does not come free, you may have to loosen the other bolts of the assembly to which it is attached.  This is not difficult.  Next, I removed the two pivot screws on the sides of the actuator.  Doing so required removal of two screws on the two brass pivot bushings and removing the small aluminum retainer that covers the pivot screws (this assembly prevents the pivot screws from loosening over time).  I used an offset screwdriver (flat blade) to remove the pivot screws.  Make sure your screwdriver fits the slot since this part is retained with loctite.  

Once I had the actuator out of the airplane, I removed the motor unit by removing the four Phillips head screws.  Separate the motor housing from the cast housing.  Keep track of the two tiny washers on the reduction gear assembly.  One of them can retained by grease in the cast housing (look for it) and the other is below the removable reduction gear assembly (the reduction gear slips off of its shaft).  Once the motor housing is removed, it has only the removable reduction gear assembly and the two washers.  I lost a washer and replaced it with a McMaster part (Chemical Resistant PTFE Plastic Washer for M2.5 Screw, Size 2.7mm ID, 5mm OD, pack of 50, Part # 95630A10).  It seems to work.  

Next, I removed the large eyelet that is screwed into the top of the inner tube.  Before you do this, NOTE THE ORIENTATION OF THE ALUMINUM BRACKET WITH RESPECT TO THE FLATS OF THE LARGE EYELET.  THIS MUST BE REINSTALLED IN THE SAME ORIENTATION DURING REASSEMBLY (THERE IS NO KEYWAY OR FLAT TO KEEP IT PROPERLY ORIENTED).  There is a small setscrew that must be removed first (also held in place with loctite - I used heat and plenty of it).

To remove the eyelet, I had to hold the inner tube so it would not rotate.  I used a set of properly sized V-blocks in a vice.  I had to heat soak the eyelet and top of the inner tube with my heat gun set at 1000 degrees.  I was then able to unscrew the eyelet assembly.  Note that these parts are easily damaged.  Heat is your friend here, the eyelet was installed with a lot of loctite in the threads.

Once the top eyelet was removed, I removed the large lead screw drive gear.  It is held in place with a tight fitting roll pin.  Again, I supported the assembly with V-blocks and positioned the gear so that I would not damage the gear teeth when driving the pin.  I tapped the pin out of the gear and then separated the gear from the screw (with the pin out, the gear slips off of the lead screw).  Now, the lead screw can be turned until it is removed from inner tube (the plastic nut in which the lead screw turns is secured in the bottom of the inner tube and can be seen in one of the pictures).

At this point, the unit is disassembled sufficiently for complete cleaning and inspection.  As the old saying goes, re-assembly is the reverse of disassembly.  Be sure the two ball bearings/races/spring washers are meticulously clean. Note correct position of the white semicircular plastic part from earlier posts in this thread. Note that the lead screw gear has the lower race for the upper bearing and the upper race for the lower bearing pressed fitted (I did not attempt to remove, I saw no need to do so).  

There has been prior discussion of grease and I am no expert.  I used a moly-based grease sold by the firearms parts vendor, Brownells.  I had it on hand.  Because the lead screw nut is plastic, I am not sure the specific lubricant is critical.  The reduction gears are metal and need an appropriate lubricant.  (Added:  Madhatter recommended Dow Corning #33 in a response to this post).

If you purchase a new actuator from FD USA, note that the upper eyelet will not have the two machined flats and will not fit as shipped.  You will either have to machine them (recommended only if you are good with a milling machine) or transfer your existing eyelet and drill and tap for the set screw.  You will also have to use lots of heat to soften the loctite, as mentioned above.  See my caution (ALL CAPS) above during reassembly.

Once assembled, you can bench test the actuator by energizing the motor.  Reversing polarity of the leads to the motor will reverse its direction.   Remember, on the bench, the microswitches will not limit travel so, DO NOT RUN THE MOTOR TO THE STOPS, YOU WILL DAMAGE THE UNIT.  

A couple more items:  The black plastic plug can be pried out and pushed back in to the cast housing.  And, I replaced the four Phillips head screws that secure the motor unit to the cast housing with Allen-head cap screws (M4 12mm length) with new lock washers.  Easier to remove with the unit installed in the airplane.

The job is not difficult. Removing and re-installing the unit and and flap regulating mechanism was tedious, however.  There are several opportunities to destroy the unit if proper procedures are not followed.  A new unit from FD is about $800.

Hope this helps someone.

Ps: In case you were wondering where I have been, I built a RANS S-20 which now has 200 hours (Rotax 912, Oratex fabric, full dual screen Skyview with AP, tricycle gear).

 

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  • 2 years later...

Hey all, I found myself back at this thread after forgetting it existed.

I no longer recommend molybdenum greases, at least not in the gearset area. I have learned that the moly can "weld" itself to certain metals. It's great for jackscrews because it will become a layer that they glide on, but not for any rolling applications, such as the ball bearings (which the flaps have a set of in the gearbox), and can in certain circumstances, interfere with gear operations.

It also apparently has pretty poor cold operating properties.

Just use straight clean lithum grease, and if you prior added moly, consider opening and cleaning all the excess off especially the gears and switch to lithium. It's not going to hurt that it exists on the jackscrew.

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I used white lithium grease on the gears and on the lead screw (jackscrew) two years ago (on another linear actuator I cleaned and lubricated) and it had no problems.  Next time I will try that Dow Corning grease that Madhatter recommended in his post just above.

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  • 4 weeks later...

Fredg,

when you disassembled yours did you remove the plate or anything off the bottom side of the motor? 
I’m getting voltage to mine but it only work’s intermittently even when I verified voltage to it. I’m curious if there is a place inside the motor that is accessible that I may find a loose connection. 
I seen 2 different types of connections on other posts. My motor has the spade connectors on the bottom that can pop off if that makes a difference. 
 

I have an idea to integrate a cheaper actuator or may just go back with one from flight design depending on what I figure out but this seems like a good start if there could be a loose connection that’s easy to get to. 

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This issue is why I lube the two flap rods in the baggage compartment every annual. I put enough liquid lube on each rod and as it runs down the rod I run the flaps all the way up and down to help spread the lube. It keeps dry metal to metal stress down. It isn't a cure all, but it certainly seems to help.

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