ALERT! FLAPERON HINGES CRACKED

[Ommadawn]

Hi all,

I was doing my annual inspection today, and found cracking in 2 of the flaperon hinge pins on the STB wing.  It's the #2 and #4 hinges from wing root, the ones with pushrod attachments. The aileron one was ok.  938 hours,  437 flight cycles in 40 years.  I expect an AD may eventually be forthcoming, but this is a heads up. If you haven't inspected your hinges really closely in a while, it may be time for a look.

Cheers

Frank

[Ommadawn]

[Ommadawn]

[Ommadawn]

[Ommadawn]

[Ommadawn]

[Ommadawn]

Arrows mark the defective hinges

[Ommadawn]

[Terry Crippen]

Yikes! Thanks for sharing the information and pictures. I'll be checking this area later today.

Looks like you have to remove the flaperons to see this? 

Terry

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[Bret Hess]

Great job Frank. Thanks.

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[johnfirth0]

It is curious that the cracks are away from the shoulder where one expects stress concentration.

Could be a manufacturing defect.

Has this glider done a lot of rough conditions flying?  Aerobatics?

Advice on removing the flaperons would be helpfull.

Thanks

John F

[xjos...@aol.com]

I had my remove a few days before. My ship has around 3000h. No findings. No aerobatics.

( The last 2000h I have this glider. )

[xjos...@aol.com]

Keep this information small in the PIK community.

We have no manufacturer and no TCI holder.

Best Regards

[johnfirth0]

The position of the cracks suggests that a bending stress was imposed  with wing flex; assuming that the bearings are

rod end type uniballs, it  suggests that the uniball is seized .  Corrosion? lack of lubrication?

JMF

[John McWilliam]

Flutter comes to mind - there must have been high loads on the hinge, and many repeat application, so flutter could well be the cause.

On 21 Mar 2021, at 15:21, johnfirth0 <johnf...@gmail.com> wrote:



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[xjos...@aol.com]

Hi.

As I saw ist I also thougt of sticking bearings and flutter.

When sticking bearings you should have more scratches in the bolt.

I expect also a flutter/vibration problem.

I saw PIKs with play up to 5mm measured at the end of the flap at the wing root.

Caused was this in all cases by worn bearings in the fuselage.

Generally the last 3 bearings before the ball connector to the wing.

This quadrant is often worn out.

How to solve:

take out this quadrant, take out the bearings out of the part.

Insert new bearings. There is a tool for. You roll in the new bearings with this tool.

And use new bolts.

You may also have bearing play in all other parts. Stick area, flap handle area, inside the wing.

With assembled and connected wings check for play and find the worn bearings. Change.

An other cause for vibrations may be rudder moment forces out of limit.

This a baby which is unloved. The Pik needs much lead at the nose of the rudders.

To stay with the rudder moments in limit.

We had one case of a PIK20B where the new owner reported vibrations in the elevator.

During aerobatics in return flight the altitude was nearly uncontrollable.

Checking the ship we found out, that one of the stupid previous owners took out the lead.

Rudder moments out of limit may happen when rudders where repainted and not melticulous checked and set.

Or when using new flap covers which are too heavy. There is a reason why they are made of light PVC.

Best Regards

[austinswill]

I am due for annual... I would also like info one removal.  Any idea if ALL models and years will be effected or not?

The good news is that the assemblies look relatively simple and could be made pretty easily.  But YIKES!

[riku rissanen]

Hi, is this PIK-20D-78 or E ?

In one 20E had some cracks in the flap / aileron system, but I havent yet heard of any hinge problems before this (important info).

Rgds, 

Riku / PIK-20A sn 20019 & sn 20009

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From: 'John McWilliam' via PIK20 <pi...@googlegroups.com>
Sent: Sunday, March 21, 2021 3:29 PM
To: johnfirth0 <johnf...@gmail.com>
Cc: PIK20 <pi...@googlegroups.com>
Subject: Re: [PIK20] ALERT! FLAPERON HINGES CRACKED

 

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[john firth]

Hi Frank

?

cheers

John F

[Ommadawn]

Some clarification. It is an E model. There was close to zero free play in the flaperon circuit. There was no binding in any rod ends. No corrosion, and lubrication was good. All hinge pivots turned freely. I have only flown last 134 hours in it, but never pushed the speed too fast. No flutter in my time. No aerobatics by me. Repetitive bending load is going to be the cause. Just need to find the mechanism of cause.

Frank

[john firth]

Left wing flap removed and pins inspected; first look says AOK but short of grease.

My remark about frozen bushing is not relevant as I find the pins and bearings have no freedom.

Maybe Riku has some comment on this.

If there was misalignment in assembly, the pins might be stressed on flap deflection.

That would explain the fatigue cracks. A broken pin would not be catastrophic  as  the flap

is held in place by the wing skin.

Full report later.

John F

[Ommadawn]

Bearings and hinges  were cleaned up prior to photos. They were well lubed and free to operate.

I have noticed that the hinge gaps are all over the place. For my money, the moving part of the hinge should sit snugly up against the pin shoulder.

The PIK hinges have huge differences in where they sit on the pins.

As much as 11.5mm gap! (See attached images.)

Hanging right out on the pin like that would impart a moment arm force that would flex the pins during every movement.

I would be interested to see someone else's hinge gaps for comparison.

[Ommadawn]

[Ommadawn]

[Ommadawn]

[Ommadawn]

The pics were taken with the flap fitted fully home.

[David Dawood]

BTW, how to replace these cracked hinges pins with new ones if no manufacture available anymore?  Can they locally be made?

David

https://groups.google.com/d/msgid/pik20/b659f321-a951-4d78-94f1-398c1dfa83d6n%40googlegroups.com

.

[Renato Tsukamoto]

Frank,

Apparently no one has answered your request yet.

I am far from my glider, which is a Pik20E 2F made in France by Siren Issoire, but I do not remember having such a gap.

I think the key may be in your phrase "the moving part of the hinge should sit snugly up against the pin shoulder".
As long as I remember, my fittings do sit against the pin shoulder.

Perhaps your pins were machined before and they did not fit new shoulders?

Perhaps your current pins are not perfectly aligned with the hole in the moving part, and that makes the moving part (usually in rotation) move along the pin (unexpected excess of linear movement) when the flaps go up and down?

Just some food for thought.

Renato Tsukamoto
Sao Paulo, Brazil.
 

 

 

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[Ommadawn]

Hi All, 

Thanks for the responses.

To remove the aileron, remove the small socket head screw on inboard end. There is a pin in the tip it should be secured with a roll pin.

Once the roll pin is removed you can screw in an  M4 screw and pull the hinge pin out.

The aileron will slide inboard until the tip hinge hits its stop.

This needs to be flexed outward about 10-15mm to allow the aileron to slide off the hinges.

However, I didn't find a problem with aileron hinges, just Flap.

We removed the hinges today.

The alignment was perfect, and there was no evidence of previous damage.

The cracks extend around the full circumference of both pins.

However we tried, we could not get the pins to snap off. I leaned in with a tube over the top and applied force in several directions. With a magnifying glass we couldn't see the cracks opening up at all.

It is possible that the cracks may only be in the chrome surface, if that is how they are made.

As the pins are hollow, one suggestion would be to ream out the inside and machine a pin to press into the middle.

This would be subject to an engineering order.

The next  step is to remove the top layer of the pin and see how deep the crack extends.

This will be done by an appropriately qualified aircraft tech.

Still early days guys, but I'll keep us all informed.

Cheers

Frank.

[Ommadawn]

[Ommadawn]

[Ommadawn]

[Ommadawn]

[Ommadawn]

[fas...@gmail.com]

Are the pins plated?  Is it just the plating that cracked?

[Ommadawn]

This is what we are hoping to establish. I am pursuing an engineering order before proceeding with the investigation. The original EIRI (Finnish) drawings don't seem to mention plating on the pins. There is mention of cadmium plating, but I suspect that is on the mounting bracket.

[Andrew Hulme]

Folks

 

I had my Pik 20D-78 (G-PIKD) in my aircraft engineer’s workshop this morning and took flaps and ailerons off.

 

One drive fitting (the one nearest the right hand wing root, No 2 hinge) showed some evidence of possible crack.  Penetrant dye showed nothing more up.

 

So he is taking the fitting off the wing, cleaning it up on the bench and having it mpi tested  (Magnetic Particle Inspection)

 

What action have you taken to fix your cracked fitting?

 

If all else fails I have a contact with a pair of wings doing nothing and he has said I can “have”……………….he means “buy” (and I guess it will be pricey) a fitting off the appropriate wing – while the fitting will be just as old it will have had much less use as the wings have been doing nothing for many years.

 

Interested to hear how you are getting on .  

 

Andrew Hulme

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[zsol...@gmail.com]

From my Pik20E looks this part  completely different.... 

[Ommadawn]

Hi  Szolt, Thanks for the additional information. Was your PIK made by Eiri? Any chance of some more images?

[zsol...@gmail.com]

mine is an Eiri Pik (s / n20283). I didn't remove the flaps because I didn't want to destroy my internal seals right now, so I tried to look under all 6 covers. I couldn't find any damage or corrosion .... everything looks like new and above all a completely different construltion than yours.

[zsol...@gmail.com]

[Jari Korjus]

Hi

We checked the hinges in our plane (PIK-20E, s/n 20292) yesterday. They are different from the ones in Frank's plane, see the photos. And they are in excellent condition! What a relief!

BR Jari and mates

PS We are flying in Finland.

[Jari Korjus]

Here are the photos

Jari

[Karl Landl]

Hello All PIK-20D Owners!

I still have a PIK-20D right wing in my trailer which is 100% intact. It was not damaged in the accident I had last year in September. In June 2018 all the pull/push rods were removed and stripped of some of the corrosion and properly treated again and re-installed. The work was done by an AA mechanic A/P - IA.

I sure would like to sell it. Btw: The PIK trailer is also available which is in great condition!

Karl

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[avrontal]

Pik20E 

4X-GMR   

sn 20226 made in Finland

No cracks found. 

Same big tolerance with flap location. Same flap, snug at one side and 12 mm on the other.

Avron

[John McWilliam]

Same with my Pik20e  s/n 20257 made in Finland, no cracks found.

No corrosion since I have long used Corrosion Block by Lear Chemical Corporation, Ontario.

I put it on every metal part, engine, controls, electrics - even the trailer lights still work after 40 years in the open weather!!

I’m amazed at the stuff yet a tin lasts many years.  Get it today! 

On 1 Apr 2021, at 15:27, avrontal <avro...@gmail.com> wrote:

Pik20E 

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[austinswill]

Well, i checked mine today... see pic. Looks like I have cracking as welll, though it does not look as bad as some of the others I have seen photos of... the question is what to do now

Sent from my T-Mobile 4G LTE Device

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[Francis Savage]

Hi all,

I would remove both flaperons and establish whether you only have a single incidence of cracking.

Don't dive in just yet and remove it, until we have established the extent of the cracking.

My pins were removed by a friend, who used an end mill to spin out the section that is welded in.

This left the cracked  section of the 2 pins undamaged, for investigation. 

I'm not touching it, but will likely forward to the GFA for analysis.

They will decide whether to issue an AD, or just the AWA.

My removal process involved cutting the wing skin.

However, my repairs guy reckoned it *may* be possible to remove the brackets with specially made up sockets, welded  on to shaped handles to reach around.

This would involve very carefully drilling and grinding off the bolt heads, as they are too close to the bracket to get a spanner on to.

(Could possibly grind a slot for a screwdriver head)

Then tapping through into the wing, and retrieving with magnet.

Replacements would need to be socket heads.

There was lots of residual strength in the pins. We couldn’t snap off as one would expect if the cracking was major.

It is possibly just in a top layer of chrome, however no documentation I have seen has yet detailed whether the pins have been chrome plated.

Odd indeed.

I’ll keep everyone appraised of any developments.

Frank.

On 6 Apr 2021, at 04:24, austinswill <austi...@gmail.com> wrote:

Well, i checked mine today... see pic. Looks like I have cracking as welll, though it does not look as bad as some of the others I have seen photos of... the question is what to do now

<20210405_122453.jpg>

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[xjos...@aol.com]

I wondered that you cutted the wing.

I reworked a 20E with was broken beyond economical repair years ago.

After glueing the wings we had to adjust the flaperon hinge positions.

But I managed this without opening the wing skin.

With a little bit patience, tools and cardanic hinged fingers.

[Demage COD]

Is there any update on the situation with the flap hinges?

[austinswill]

Any update on this?

[xjos...@aol.com]

Update from germany: in our WA group are about ten 20E. Checked. No cracks.

[Andrew Hulme]

My Pik20D-78 in UK had what we thought might be one.  It was only on the surface and polished out

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[Dale notrequited]

Just finished inspection of my PIK20D-78  1800 hours 750 flights.

Didn't need to remove the flap. I removed the retaining bolt and push rod covers, slid the flap inboard 12-13 mm to expose the pins .

Cleaned the old grease away and have no cracks.

[austinswill]

Frank,

Any chance on an update? did you send the part off for analysis?

  I am in a holding pattern and have grounded my glider.  I found 1 pin that has what MIGHT be a crack.  Rather than tear into the thing I would rather wait and see if it is a coating or something non critical. This topic has gone quiet and I would love to know if any new information will even be coming... If not I have some work to do.

I really hope to fly the glider this summer.

Austin

[Andrew Hulme]

You don’t need to tear into the wing to take of the brackets

 

Mine in the UK proved not to be cracked

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[austinswill]

Hey everyone, I am still working on this issue.  I am having difficulty figuring out how the ailerons come off.  At the very wing tip there was a cotter pin that went through a longer pin that serves as the hinge pin.  This hinge pin appears to be threaded internally.  However there is no way for me to grab it to pull it out to free the aileron.  Am I suppose to thread in a bolt to pull it?  What am I missing?  I can shift the aileron inboard, but with this pin in place I dont see how the aileron can possibly come off.

[xjos...@aol.com]

Oh dear...

First you have to remove the security pin. If there is one.

It works without this pin. The bolt has no chace to get out or in when not secure.

I have mine since 17 years and never inserted this pin in. Nor had pin movement.

Yes, you have to screw in a bolt.  Then pull the outer hinge bolt outwards with help of this bolt.

You will only get the aileron disassembled when you disassemble the flaperon first.

And do not wonder...

Even when you take out the ( or later in ) the aileron you have to bend it around the outer hinge.

This is normal.

Best Regards

[Steve Beatty]

I haven't received any EMAILS in  a long time  Anybody getting any air time ? 

 Steve Beatty   Airscrew Performance 

[John McWilliam]

Not me - maybe all the Piks are serviceable!!

On 28 Aug 2021, at 04:40, 'Steve Beatty' via PIK20 <pi...@googlegroups.com> wrote:



I haven't received any EMAILS in  a long time  Anybody getting any air time ? 

 Steve Beatty   Airscrew Performance 

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[Francis Savage]

I logged just under 4 hours in last 3 weeks, late weak Winter thermals here. The PIK20E is a heavy bird and not easy to handle in light conditions. Spring is almost upon us, and a bountiful Summer season beckons down under. In South Australia it is common to have Summer days of 38-40C, with huge thermals and vast open farmer's fields tp the horizon. Can't wait!

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[fas...@gmail.com]

I've got about 25 hours in my PIK20D this season.

https://www.onlinecontest.org/olc-3.0/gliding/flightbook.html?sp=2021&st=olcp&rt=olc&pi=69440

[Tele2]

Yep in europe the season is not great but still some airtime

Interesting failure, partial engine electronics not working. Root cause was the ground connection cable breakage ( the ground of the engine bracket that is moving ( by rotation) during engine extraction. Similar failure appearance as the safety sensor malfunction effect.

Seb

 

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From: pi...@googlegroups.com <pi...@googlegroups.com> on behalf of fas...@gmail.com <fas...@gmail.com>
Sent: Saturday, August 28, 2021 4:23 PM
To: PIK20
Subject: Re: [PIK20] Flying ?

 

I've got about 25 hours in my PIK20D this season.

https://www.onlinecontest.org/olc-3.0/gliding/flightbook.html?sp=2021&st=olcp&rt=olc&pi=69440

On Friday, August 27, 2021 at 11:46:24 PM UTC-6 Ommadawn wrote:

I logged just under 4 hours in last 3 weeks, late weak Winter thermals here. The PIK20E is a heavy bird and not easy to handle in light conditions. Spring is almost upon us, and a bountiful Summer season beckons down under. In South Australia it is common to have Summer days of 38-40C, with huge thermals and vast open farmer's fields tp the horizon. Can't wait!

On 28 Aug 2021, at 14:52, 'John McWilliam' via PIK20 <pi..@googlegroups.com> wrote:

Not me - maybe all the Piks are serviceable!!

On 28 Aug 2021, at 04:40, 'Steve Beatty' via PIK20 <pi...@googlegroups.com> wrote:



I haven't received any EMAILS in  a long time  Anybody getting any air time ? 

 Steve Beatty   Airscrew Performance 

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[Coyne Publishing]

I had some decent flights earlier this year, but a health problem has grounded me since June 25. Hoping to get the medic’s okay to fly again after my September appointment.

Cheers,

Chuck Coyne

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[Rob Frith]

I have had an all right year so far, 80 hrs and hopefully a few more hours, good considering a slow start.  Hopefully a few more to go, but near the end of the year for me.

Cheers Rob

PIK2OE

Get Outlook for Android

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From: pi...@googlegroups.com <pi...@googlegroups.com> on behalf of Coyne Publishing <cco...@rtrmag.com>
Sent: Saturday, August 28, 2021 4:11:58 PM
To: Francis Savage <franka...@internode.on.net>
Cc: John McWilliam <johnmc...@mac.com>; Steve Beatty <gas...@aol.com>; pi...@googlegroups.com <pi...@googlegroups.com>

Subject: Re: [PIK20] Flying ?

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