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EUROPA PIP-PIN RECESS
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nwcmc(at)tiscali.co.uk
Guest

Posted: Thu Jun 21, 2007 1:48 am Post subject: EUROPA PIP-PIN RECESS

 	  Quote: 	
		  This is like treating the symptom and not the illness. The play comes

from 
	


the TP10 fixing on the torque tube. If the pip pin fixes well, the play

is 

tranferred on the glue of the TP6 in the foam! If there is any flutter

then 

you can imagine how long it will take before the TP6 comes untie.<



I agree that the problem starts with the fixing of the TP10's. However

the design of the pip pin recess is still important. A small amount of

relative movement between the tailplanes (caused by the less than

perfect fixing of the TP10's) is not in itself dangerous. Neither is

disbonding of the TP6's by itself. What is dangerous is if the

tailplanes move outwards allowing them to disconnect from the TP10 pins.

If the TP6 becomes disbonded (by for instance twisting loads) it is

possible in some cases for the tailplane to move outwards sufficiently

for the tailplane to become disconnected from the TP10 pins. The size

and shape of the recess is important in this respect. A recess sidewall

which is close to the pip pin head on the inboard side can prevent

outward movement of the tailplane whilst the pip pin is in place even if

the TP6 is disbonded.



Although flutter has been mentioned (and can be a very dangerous

condition), a possible cause of this inflight loss of control is a

tailplane moving outwards enough to become detached from its TP10 pins.

Regardless of the TP10 fixing it is important that this is not allowed

to happen.



I know that the PFA is looking at a modification to the pip pin recess

so we will just have to wait to see what they come up with.

Nigel Charles

jan.de.jong(at)xs4all.nl
Guest

Posted: Thu Jun 21, 2007 2:21 am Post subject: Europa pip-pin recess

Hallo Jos,



I did the same thing. Locked both TP6 and TP5 in 3 layers of bid tube 

before bonding tube into place with flox and bid laps. TP6 and TP5 

deeply scored beforehand using dremel cutting disk. I am confident that 

TP6 will not go anywhere.

Dutch CAA requires all mandatory mods executed for CofA. Finnish CAA no 

different I presume.

So I hope that PFA will bless at some point.



Jan de Jong

#461, making slow progress.

rparigor(at)suffolk.lib.n
Guest

Posted: Thu Jun 21, 2007 4:50 am Post subject: EUROPA PIP-PIN RECESS

Hello Fred



"Ron...a picture's worth 1000 words...thanks, and I need a few more words:

I take it the shoulder  of the screws is what penetrates the TT and

bushes, and both the CF tube and the embedded and threaded "base" you

turned help to keep the outer bush bonded in place."



The shoulder of the screw acts like a pin, instead of 2 balls to hold pin

in place I used threads (need a wrench for prying hands to remove). The

inner and outer bushings are glassed to plywood ribs. The CF tube is

glassed to each bushing and fillet that is holding bushing to rib. The

lower insert does not really help with bushing bond, it is glassed to CF

tube and rib fillet (perhaps helps a mini tad but not much). The top

receptical does not help bushing bond, it is bonded to recess and a bit of

CF tube on the bottom, and a flox ring on top bonds it to outer 2 UNI.



Sorry, not much in the way of more pictures, will try to describe:



1) First it is absolute imperative TP9 and two TP12s are well stuck to TT

TP4. You can search Archives "Ron Parigoris Torque Tube" for a description

how I made the fit right. Slop between TP4 TT and TP12 stabilator drive

arm, if enough will allow the pip pin, or in my case the shoulder screw to

begin to allow torque to be applied the the outer bushing. If built to

plans, the bond on the outer bushing is not tremendous robust, and if you

apply torque to it, it could easily debond where if no torque was applied,

it could have lived a happy life. Read the PFA procedure careful

describing wiggle of pip pins, they are trying to determine if torque is

being applied to outer bushing. Again if there was no motion between TP4

and TP12, the pip pins could not drive, only motion can allow the

undesirable drive. It is possible that there is motion but within

allowable limits. If this is the case it is possible you could debond the

outer bushing as described if the fit in the TT and outer bushing and pip

pin is tight. As described the only reason for the Pip Pin is to keep the

stabilator on the TT, and the TP12 drive arms engaged to the TP13 driven

bushings that are bonded into the root plywood rib. Just a side note my TP

13 bushings were bonded in place with rapid epoxy and only 50 % coverage

and also in the wrong position where the angle of attack was not the same

on both stabilators. Oval holes, well scuffed washer under the step on the

bushing and redux/Flox repaired. OK I hope not confusing too much, but the

pip pin only needs to contact to prevent any outboard movement. The fit to

the outer bushing can be fairly close and round, but the TT if radially

elongated (I did mine ~.020" each way) still will hold the Stabilator

inboard, but if motion developed between TP4TT and TP12 stabilator drive

arm, the TT elongated pip pin hole could not drive the pip pin (if less

than max. recommended motion) before the pin hit the side of the oval.



2) My "Mutilation" was done after my accelerated tailplanes were built.

The Redux used on metal first pass bonds a bit better than Aeropoxy. A bit

of flexibility that can allow things to load just a tad more even before

joint lets go. Idea is to make sure inner and outer bushings are well

stuck to plywood insert ribs. The club mod is a good one (although I still

like redux first pass on metal.) Connecting the bushings helps prevent

twisting forces from debonding. When only the inner bushing is taking the

full load when sliding on the stabilator to TT, there is a lot of force

due to leverage that can be applied to that lone bushing. The CF Rowing

skull oar has a very slight taper. The second the TT enters the CF it is

held from allowing this undesirable torque upon assembly, and it guides

the tip into the outer bushing.



3) OK so my inner and outer bushings are stuck to stabilator and each

other pretty good. If they stay stuck then the outer bushing is a fine

means to pin the stabilator to the TT. 006 pip pin recess dilemma is

trying to make sure that if the outer bushing debonded that the stabilator

was not allowed to move outboard and have TP12 drive arm pins, disengage

from the stabilator driven TP13 bushings by ensuring that the pip pin

recess is strong enough to take outboard forces. I am not certain about

the minimum base requirements if plans not followed exact, but I suspect

it is to help hold the outer bushing a bit better. I was able to contact

with my glass reinforcement/filled a little more than 1/2 the

circumferance of the bushing from the bottom, and my CF tube had half of

it sneak around by twisting it so it was reduxed to the top of the

bushing! On a new build following the Club Mod is pretty easy, on

completed stabilators it took a bit more creativity.



Even though my outer bushing is stuck pretty well, I made sure my bottom

threaded insert is stuck well to the outer plywood rib. My top receptacle

is stuck on the bottom pretty well on the BID of the pip pin recess, then

I filled with foam and left a space for a flox fillet to the top 2 UNI

plies that completed the top and left it flat except for a perhaps 3/8"

hole.



4) One more time, my shoulder screw goes through top receptacle, top of

outer bushing, through top of TT that is elongated .020" each side,

through the bottom of the TT that is elongated .020" each side, through

the bottom of the outer bushing, through CF tube and glass, and into

threaded bottom insert.



First means to hold stabilator on TT is shoulder screw to outer bushing

top and bottom and TT top and bottom.



If Outer bushing debonded second means is shoulder screw to upper

receptacle to both sides of TT and on bottom CF tube, glass and insert. 



Hope this is clearer than mud?



Ron Parigoris

josok-e(at)ukolo.fi
Guest

Posted: Thu Jun 21, 2007 7:20 am Post subject: Europa pip-pin recess

Hi Jan



With the club mod it sure feels and looks rigid, but i would like to see  

some blessing after what happened anyway.

There is absolutely no play anywhere now. Will it stay that way?



Regards,



Jos Okhuijsen



http://www.europaowners.org/kit600

-- 

workshopcam http://www.okhuijsen.org/plane

http://www.europaowners.org/kit600

fklein(at)orcasonline.com
Guest

Posted: Thu Jun 21, 2007 1:31 pm Post subject: EUROPA PIP-PIN RECESS

Ron,



I first want to acknowledge you for taking the time and effort to 

respond to my queries with such a thoughtful and nuanced explanation of 

what you've done and why. Your willingness to do so creates the real 

value I find in the forum discussions of so many critical life safety 

issues.



Thanks so much,



Overall, you seem to have taken the bull by the horns in addressing the 

apparent fragility of the bonds between the TP6 sleeve/bush, the 

plywood insert, and foam...recognizing that your fix would be suspect 

in the UK.



On Thursday, June 21, 2007, at 05:49  AM, <rparigor(at)suffolk.lib.ny.us> 

wrote:



 	  Quote: 	
		   Just a side note my TP13 bushings were bonded in place with rapid 

 epoxy and only 50 % coverage

 and also in the wrong position where the angle of attack was not the 

 same

 on both stabilators.


	


Being alerted to your condition, I've mounted my stabilators 

(factory-built in my accelerated XS kit) to the torque tube assembly 

and have found that the trailing edges, as measured at the trim tab 

hinge line, vary by .375 inches; this translates to an angle of 1.19 

degrees; thus the AOA of my stabilators have a differential of that 

amount which is troubling to say the least, not only from a visual 

standpoint, but more importantly from an aerodynamic standpoint as a 

potential contributor to flutter. I attribute this differential to the 

misplacement of the TP13 bushes in the plywood inserts at the root of 

the stabilator.



 	  Quote: 	
		   Oval holes, well scuffed washer under the step on the

 bushing and redux/Flox repaired.


	


By "oval holes", I assume you're referring to the holes in the TT for 

the pip pins. Since the TP13 bushes set the AOA of the stabilators, I 

don't see how elongating the pip pin holes in the TT can "repair" this 

problem. I find NO information in the build manual as to an acceptable 

tolerance in the AOA between the two stabilators. The only fix I can 

imagine would be to remove the TP13 bushes from one stabilator, fill 

the void with flox, redrill for and replace the TP13 bushes so that the 

two stabilators are in alignment with identical AOAs.



So all you guys w/ the "accelerated" XS kits: In your build (or now 

that you're flying), have you found the same condition as I've 

described above? If so, has it been remedied (how?), or has it been 

ignored?...and is really no problem whatsoever?



(I'm always doing checks on my anal-retentiveness quotient.)



Input appreciated,



Fred

A194

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jan.de.jong(at)xs4all.nl
Guest

Posted: Thu Jun 21, 2007 3:38 pm Post subject: Europa pip-pin recess

Hi Jos,



I am confident that the club mod will keep TP6 in place if it is never 

required to do other than its intended job - keeping the stabilator from 

sliding off TP4. The bid tube will in any case be a backup retainer 

between inspections.

But an official blessing will be needed.



Regards,

Jan de Jong

g-iani(at)ntlworld.com
Guest

Posted: Thu Jun 21, 2007 11:23 pm Post subject: Europa pip-pin recess

Jan



I do not understand your reference to "an official blessing will be

needed.  The Club mod is a fully approved PFA standard mod.



Ian Rickard  #505 G-IANI XS Trigear

Europa Club Mods Rep (Trigear)

e-mail mods(at)europaclub.org.uk   

   or direct g-iani(at)ntlworld.com

josok-e(at)ukolo.fi
Guest

Posted: Fri Jun 22, 2007 12:14 am Post subject: Europa pip-pin recess

Ian,



We do have the approved modification, so we do not have the standard,  

probably too weak situtation.

I opted for this mod, because the original "looked" improvable.

How does this approved modification change the need for a a "standard" pip  

hole and what other influences may there be?

If in the UK,would we be grounded too?



Regards,



http://www.europaowners.org/kit600

karelvranken(at)hotmail.c
Guest

Posted: Fri Jun 22, 2007 1:56 pm Post subject: EUROPA PIP-PIN RECESS

Nigel,

I can follow your explanation except when you write: "What is dangerous is 

if the taiplanes move outwards allowing them to disconnect the TP10 pins." 

TP10's are nylon tubes. You mean perhaps the pins on the TP12?

The pip pin recesses on F-PKRL were made conform the build manual, even 

stronger.

The problem I would talk about is the play between TP12 and TP4.

TP4 and TP12 are delivered with holes. When you have to fix them together 

with the nylon TP10 tubes then you have to drill very carefully to allow the 

clevis pins to be installed. Afterwards I found that the play occured on 

starboard side by moving the TP12 by the pins. The mass balance keeps the 

TP4 easily in place. So port side no play. When I did the same test on Dirk 

Oyen's OO-145, it gave the same result. Factory tolerance? Bigger holes and 

clevis pins wasn't a solution (Rowland Carson). Others do have the same 

problem hence the discussions: clamps or taper pins. Finally no definite 

solution nor mandatory modification. The play measured at trailing edge may 

not be more then 1/2". I will have no play at all. So if we are waiting for 

a modification to keep a fluttering tailplane on board then I say: You treat 

the symptom and not the illness.

Karel Vranken, F-PKRL waiting for next mod and if my problem is not 

concerned then Bob Harrison may have an order from me.

---

grahamsingleton(at)btinte
Guest

Posted: Fri Jun 22, 2007 2:45 pm Post subject: EUROPA PIP-PIN RECESS

Karel

You are right about treating symptoms. I too am still very puzzled about 

the cause of William's accident. There are certainly a lot of Europas 

around with 1/2" of looseness in the tailplanes. This arises from that 

rather unwise requirement to drill the TP 10s through the torque tube 

and the TP4s. imho that is where most of this particular problem starts.



The other problem is the security of the TP6 bush which is required to 

keep the tailplane in place. It can come loose from more than one cause.

Slop in the TP12 allowing hammering while taxying on rough ground.

Damage caused during derigging or on the trailer.

I suspect this unhappy situation is, like most accidents, the result of 

more than one factor combining to produse an accident.

I do find it incredible that it was possible to pull the wings off at 90 

kts.( But then I haven't done the sums.)

Graham



karelvranken wrote:

 	  Quote: 	
		   

 <karelvranken(at)hotmail.com>

 

 Nigel,

 I can follow your explanation except when you write: "What is dangerous 

 is if the taiplanes move outwards allowing them to disconnect the TP10 

 pins." TP10's are nylon tubes. You mean perhaps the pins on the TP12?

  Others do have the same problem hence the discussions: clamps 

 or taper pins. Finally no definite solution nor mandatory modification. 

 The play measured at trailing edge may not be more then 1/2". 

 Karel Vranken,

karelvranken(at)hotmail.c
Guest

Posted: Sat Jun 23, 2007 9:06 am Post subject: EUROPA PIP-PIN RECESS

Thanks Graham,

I hope that other big guns start to shoot so that it is heard in the PFA 

bureau.

Karel Vranken.

---

Fergus Kyle

Joined: 03 Jun 2007
Posts: 291
Location: Burlington ON Canada

Posted: Sat Jun 23, 2007 6:40 pm Post subject: Europa pip-pin recess

Hello,

	I don't quite understand the process of elongating the pip-pin

holes. Mine are tighter'n a drum all round and so they touch everywhere

(presumably), whereas if I were to elongated any, then won't the long side

only be touched tangentially by the pin. Won't this then permit the long

side to be slowly indented, and won't the condition accelerate as the event

(and inner surface) wear on?

	What am I missing here?

Happy Landings

Ferg

Wiring, wiring, wiring

jonsmitheuropa(at)tiscali
Guest

Posted: Sat Jun 23, 2007 11:36 pm Post subject: Europa pip-pin recess

Hi!

The factory news letter number 21, "tech talk" page 14 describes why the pip 

pin holes in the torque tube should be elongated.  The paragraph is entitled 

"torque tubes".

Regards, Jon



---

jan.de.jong(at)xs4all.nl
Guest

Posted: Sun Jun 24, 2007 8:09 am Post subject: Europa pip-pin recess

Sorry, my concern is premature. My reasoning: assuming an official fix 

for better TP6 retention and assuming this fix incompatible with club 

mod then club mod must remain blessed  without fix.



Jan de Jong



G-IANI wrote:

 	  Quote: 	
		   

 Jan



 I do not understand your reference to "an official blessing will be

 needed.  The Club mod is a fully approved PFA standard mod.



 Ian Rickard  #505 G-IANI XS Trigear

 Europa Club Mods Rep (Trigear)

 e-mail mods(at)europaclub.org.uk   

    or direct g-iani(at)ntlworld.com

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