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LDS woes


Phil.Taylor
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Phil.Taylor

We all love fixing other folks problems - try this one - looking forwards to hearing some suggestions - I'm stuck ☹️

Its the FS4.3 that was on the BARCS ads. I was surprised that it had LDS linkages - I had expected RDS for that era of plane. Maybe a retrofit? Setting it up, the left aileron LDS linkage was binding/squeaking/graunching - wanted to get the servo & linkage out to sort it out. BUT - the pin wouldnt budge. More & more force, with needle nose pliers, eventually the pin moved over a bit- then the pliers slipped & scratched the wing surface (general cursing). That at least freed thing up a bit - less noise but still not 100% - enough to get it in the air.

Maiden (after several owners!) flight this evening - all went well. Next flight - powered up & no left aileron - not good. Push the aileron up/down & the servo tries to move it & gives up. Powered off the surface & servo seem to move ok so its not locked up solid. So - theres now both a linkage problem and a servo problem ☹️

I need to remove the servo and the LDS linkage to sort it all out. 

I'm open to all suggestions here - how on earth do I remove that stuck LDS pin? - without messing up the wing even more. The really savage version would be to drill/dremel/destroy the LDS arm by the pin - but the pin would still be there...

Suggestions?

Phil.

LDS_1.thumb.jpg.abc48b09a3b030eb18b3dda9b0996fb3.jpgLDS_2.thumb.jpg.9b5c783c1868c0dbd3f4357d85fad98c.jpg

 

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rc-soar

Heat the pin briefly with a soldering iron, and repeat until it can be tapped out. Worked for me on my PP2!

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Graeme_M

Hi Phil,

I have a long ish drift made from piano wire coming in from the Aileron/Flap junction, keep it as straight as possible to prevent flexing, this works quite well.

045C1B50-33B3-4039-AB7C-5CC6A577E6B1.thumb.jpeg.211aa3f8255c0a16df41a5108ddc8d01.jpeg

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You should be able to tap it out Phil rather that try and pull it out .  What are you going to do once its out though ?

 

Andy

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Phil.Taylor
47 minutes ago, Andy_B said:

What are you going to do once its out though ?

Andy

Replace the servo - the plane came with a couple of spare 6125s - investigate the binding - I suspect its cos the pin is too tight in the arm

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23 minutes ago, Phil.Taylor said:

Replace the servo - the plane came with a couple of spare 6125s - investigate the binding - I suspect its cos the pin is too tight in the arm

more likely the arm is out of line with the horn ....and thats what has nailed the servo 

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Phil.Taylor
5 minutes ago, Andy_B said:

more likely the arm is out of line with the horn ....and thats what has nailed the servo 

quite possibly - will get a full check-over

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oipigface

I had this problem a while ago. There’s a thread on here about it somewhere. I wound up tapping it out using a light hammer and short piece of wire of lighter gauge than the pin. It’s not easy, but I couldn’t find any thing easier.

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isoaritfirst

I used a long drift in the past but now I grasp the pin with as much grip as I can muster in some needle nose pliers. I then tap the pliers with a hammer. The wing root up against something to ensure the tapping is as effective as possible.

Tapping seems to work well, but you do need to grip as hard as you can and tap lightly.

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Phil.Taylor

Thanks for all the suggestions - will try some this evening

Phil.

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Do you have any ball link pliers?

135839557_20210615_2039091.thumb.jpg.6404795a403830c375fac3fa6f966e2a.jpg

If so, cut a short length of thinner wire which you can hold in pliers, insert into the open side of the joint and locate the wire other end in the recess of the pusher on the plier with the fork over the other side of the joint and squeeze.  No strain on the fixed bits.

Hopefully easier to do than explain.

HTHs.

Jerry

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Phil.Taylor

Its out !!!

started with Mike's soldering iron heat

then a thin nail held in a surgical clamp - nail pointy end on the pin - tap tap tap with a hammer - that got it moving a bit, until the nail wouldn't go in anymore

then it was Mike's needle nose pliers held tight & tap tap tap with the hammer - bit by bit - that shifted it

final wiggle with the pliers - out it came

very big THANK YOU for all the suggestions

the pins in the LDS arm & roll drive are/were very tight - way too tight - no wonder it was creaking & groaning - and killed the servo

Phil.

Pin_out.thumb.jpg.db42a6714c837c5a46a255263862cbbc.jpg

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Phil.Taylor

just powered the wing up to check the servo - its dead - no movement - and the casing was getting very hot...

Phil.

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Phil.Taylor
4 hours ago, wookman said:

What are the other three like?

Flaps are fine & the other aileron was a bit stiff but freed up with some serious wiggling - strange that just one is really bad - but it is an early example of LDS - been in there from new

Phil.

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isoaritfirst

Check the servo head pieces Phil. Those early ones, once tightened down squeezed the pushrod, there was no tolerance.

Prise it apart and sand the push rod narrower and be careful when tightening back onto the servo.

 

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jay bee

Phil l think Mike has nailed it,the bolt that screws into the servo spline can pull/push the rotating arm 

onto the body of the servo casing.l had the same problem.

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Phil.Taylor

All back in & running very smoothly with a good spare 5125 servo that came with the plane 😀

The LDS arm holes needed very little work to go from way-too-tight to just-right. Servo heads / roll drives went on fine - no pushrod squeezing & these ones wont push down onto the servo case. Geometry all checked & good. LDS pin went back in fine - Mike's needle nose pliers & tap tap tap is definitely a good way to go - thanks Mike. The wipers got a bit of sanding in a couple of places too. And - its not only smooth but nice & quiet now - that old servo buzzed like crazy - poor thing - RIP servo, it lived a hard life.

Phil.

 

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