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topglock(at)cox.net
Guest

Posted: Sun Jul 15, 2007 10:27 am Post subject: Europa Tailplane - Mod 73

All,



I've read, with great interest, all the suggestions and discussion.  I'm 

no engineer, but I have a pretty good idea of what I would do, should I 

find any evidence of disbonding of the tailplane bushings.  And, I 

believe it could be done with very little cosmetic damage to the 

tailplane.  I like the solid tube idea and would build off of that.  

Basically, a tube, of the appropriate length, with two 1/4", round, 

metal rods welded fore and aft, on centerline.  The rods wouldn't have 

to run the full length of the tube, but it certainly wouldn't hurt.  The 

purpose of the rods would be to further stabilize the tube and prevent 

it from twisting. 



Should the original bushings become disbonded, it should be a fairly 

simple task to remove the old bushing (even if it required opening the 

wingtip), remove the inner bushing and modify the foam and ribs, to 

accomodate the new shape of the tube.  Inserting the new tube would be 

as simple as applying a thin coat of Redux to the tube and inner walls 

of the foam, plugging the outboard end of the new tube and pushing the 

assembly in.  The new tube would then be drilled to accept the standard 

pip pins.  Adding covers to the pip pin access holes would further 

remove the possibility of a pin becoming dislodged.



Seems to me that the new assembly would be extremely strong and should 

remove any further chance of the tailplanes pulling away from the drive 

pins.



So, am I way off base, of does this idea hold water?



Jeff - Baby Blue

300 hours and finishing up her 2nd annual...



Karl Heindl wrote:

 	  Quote: 	
		   





 Nigel,



 I understand all that and your mod should have been made standard a 

 long time ago. But what about older Europas ? We hear reports about 

 disbonded TP6s but we don't hear how they were repaired. I really 

 would like to know. A suitable retrofit mod should also have been made 

 available as soon as this problem was known.

 I still say that there is no way the tailplane can move if the pip pin 

 head is firmly against solid material on the inboard side. You say 

 there is always a gap, but that gap is filled with floxed epoxy, and 

 the head is inside a close fitting plastic pipe in my case. I think 

 another builder recently told us about a similar mod he made. The 

 remaining space around the pipe is also filled with epoxy. Of course 

 all these solutions are based on theory and only a lab test could 

 verify the claims.

 When my TP5s disbonded from trailering I was kicking myself for not 

 having installed a one-piece pipe, but in those early days I was very 

 careful to follow the build instructions precisely. I stll think that 

 a retrofit of a one-piece sleeve  would be more than strong enough to 

 prevent any future disbonding, and would be a relatively easy solution 

 where the TP6s have already disbonded.



 As far as the accident goes, we still don't have any real conclusive 

 evidence about the sequence of events. Only a number of theories. Only 

 a wind tunnel test would verify the flutter theory, but who is going 

 to pay for that ? Eyewitness reports can be very misleading.

 If the wing trailing edge pin came off first, is it possible that the 

 pilot was getting set up for landing and deploying flaps and 

 undercarriage ?



 I also like the other suggested solutions where a lock is put behind 

 the TP12

 Karl

>

> Karl,

>

> I have attached below, an excerpt of a long mail I sent to the PFA that

> describes a sequence of events that could lead to the tailplain moving

> outboard. Out of interest, there is always a gap between the pip-pin 

> and the

> face of the rib.

>

> This was sent before the current Mod 73 was issued, but you will see 

> why the

> temporary remedial action has been to reinforce the pip-pin hole.

>

> Nigel

>

>

> -------------------------------

> Excerpt

>

> ...... The only thing preventing each tailplane moving sideways is a 

> single

> pip-pin that passes through the TP6 bush and into the TP4 torque 

> tube. (See

> Fig.5 Chap 4)

> The design relies on a good bond to hold TP6 in place, however only the

> protruding outer 12mm (just 8mm on TP5) is required to bond to the 

> tailplane

> rib that will subsequently be laid-up onto it. Epoxy adhesive does 

> not bond

> well to stainless steel - so the potential for this bondline to fail is

> great.

> This tiny bondline is the only "design" load path to prevent the 

> tailplane

> moving laterally. If the bond failed, the loose TP6 bush would tend 

> to push

> its way inboard into the soft blue foam, allowing the tailplane to move

> outboard. The TP5 bush would offer no resistance since it would 

> simply slide

> along the TP4 torque tube.

>

> In some early Europas, this TP6 bush has de-bonded and it is only the

> laminations into the "PipPin" access hole that prevent any lateral 

> movement

> of the tail-plane. This lamination was never intended to be 

> structural. If

> the aircraft is high-time and habitually operated off rough strips, 

> it is

> logical to predict that the continual fretting would cause the glass 

> around

> the pip-pin hole to chafe, opening up the hole to a point where the 

> whole

> tailplane could slide far enough laterally to allow the tail-pane 

> drive pins

> (TP12) to disengage from their drive bushes (TP13) - The tailplane would

> then oscillate violently with catastrophic results.

>

> Modification 10672) calls for both the Stainless TP5 and TP6 bushes 

> to be

> laminated into an epoxy/Bi-Directional Glass tube before inserting 

> this into

> the tailplane TP2 cores and laminating the ribs. This bonds both 

> bushes over

> their entire surface area, significantly increasing the bond area and 

> more

> importantly, physically tying TP5 with TP6 and both the inner and 

> outer ribs

> together. With this structure, the entire bond surface area and both 

> ribs

> would have to fail before the tailplane could move sideways.

>

> The loadpath is through the mod 10672 and not through the outer skin and

> pip-pin hole - a significantly better engineering solution.

> -

>



 _________________________________________________________________

 Watch all 9 Live Earth concerts live on MSN.  http://liveearth.uk.msn.com

pete(at)lawless.info
Guest

Posted: Sun Jul 15, 2007 11:10 am Post subject: Europa Tailplane - Mod 73

So how do you drill the new pip pin holes though the outside new tube to

line up with the existing holes in TP4?



--

mikenjulie.parkin(at)btin
Guest

Posted: Sun Jul 15, 2007 12:25 pm Post subject: Europa Tailplane - Mod 73

Glen and Ron P.

  

 I am a pilot and not an aerodynamicist.  However,  having just blown off the dust from my old aerodynamics textbook, what you are  saying is not strictly correct.  It may be that you are correct with  relevance to the europa, but it really does depend on where the C of G  is!!

  

 If one considers the main wing, if the Aerodynamic Centre  (AC) is aft of the CofG the wing would be in a stable configuration. That is  without any opposing forces the aircraft would pitch down.  On the other  hand, if the AC was forward of the CofG without any opposing forces the aircraft  would pitch up.

  

 As the stabiliser is well aft of the aircraft CofG it is  always stabilising.  But it is possible to have a de-stabilising wing with  a stabilising tailplane.  Overall the aircraft would be stable as long as  sum of wing and tailplane Cm/Cl curves have a negative slope.

  

 The point is that if the wing AC is forward of the CofG  with no other forces affecting it the aircraft will pitch up, not  down.

  

 Most aeroplanes I have flown 'balloon' on flap selection,  particularly with the first notch of flap.  However the nose down effect of  selecting flap is caused by a rearward movement of the Centre of Pressure which  creates an increased moment about the C of G which requires the adjustment of  the tailplane trim - all be it with a slightly increased nose down  attitude.  Much the same I suppose as saying the pitch down is caused by an  increase in negative Cm.

  

 Having said all that looking at the diagram in the  aircraft handbook in the weight and balance chapter as a rough guestimate it  would appear that the C of G of our europas (58-62.5in AOD) would always be  forward of the Aerodynamic Centre which is approximately 25% chord in subsonic  flow.

  

 regards,

  

 Mike.

  

  

 [quote]   ---

kheindl(at)msn.com
Guest

Posted: Sun Jul 15, 2007 12:48 pm Post subject: Europa Tailplane - Mod 73

Jeff,



I think that the TP5 and TP6 can be removed with heat without cutting any 

holes. Also, it would  be easier to pre-drill the pip-pin holes, as you can 

then do a trial fit before bonding. To get the position exactly right I 

would attach a template (using double-sided tape) with a  1/4 inch hole over 

the top of the recess, first lining up all 3 holes with a 1/4 inch shaft or 

bolt, before removing the TP6. Just one of my crazy ideas.



Karl



 	  Quote: 	
		  From: Rman <topglock(at)cox.net>

Reply-To: europa-list(at)matronics.com

To: europa-list(at)matronics.com

Subject: Re: Europa Tailplane - Mod 73

Date: Sun, 15 Jul 2007 13:25:12 -0500






All,



I've read, with great interest, all the suggestions and discussion.  I'm no 

engineer, but I have a pretty good idea of what I would do, should I find 

any evidence of disbonding of the tailplane bushings.  And, I believe it 

could be done with very little cosmetic damage to the tailplane.  I like 

the solid tube idea and would build off of that.  Basically, a tube, of the 

appropriate length, with two 1/4", round, metal rods welded fore and aft, 

on centerline.  The rods wouldn't have to run the full length of the tube, 

but it certainly wouldn't hurt.  The purpose of the rods would be to 

further stabilize the tube and prevent it from twisting.



Should the original bushings become disbonded, it should be a fairly simple 

task to remove the old bushing (even if it required opening the wingtip), 

remove the inner bushing and modify the foam and ribs, to accomodate the 

new shape of the tube.  Inserting the new tube would be as simple as 

applying a thin coat of Redux to the tube and inner walls of the foam, 

plugging the outboard end of the new tube and pushing the assembly in.  The 

new tube would then be drilled to accept the standard pip pins.  Adding 

covers to the pip pin access holes would further remove the possibility of 

a pin becoming dislodged.



Seems to me that the new assembly would be extremely strong and should 

remove any further chance of the tailplanes pulling away from the drive 

pins.



So, am I way off base, of does this idea hold water?



Jeff - Baby Blue

300 hours and finishing up her 2nd annual...



Karl Heindl wrote:

>

>

>

>Nigel,

>

>I understand all that and your mod should have been made standard a long 

>time ago. But what about older Europas ? We hear reports about disbonded 

>TP6s but we don't hear how they were repaired. I really would like to 

>know. A suitable retrofit mod should also have been made available as soon 

>as this problem was known.

>I still say that there is no way the tailplane can move if the pip pin 

>head is firmly against solid material on the inboard side. You say there 

>is always a gap, but that gap is filled with floxed epoxy, and the head is 

>inside a close fitting plastic pipe in my case. I think another builder 

>recently told us about a similar mod he made. The remaining space around 

>the pipe is also filled with epoxy. Of course all these solutions are 

>based on theory and only a lab test could verify the claims.

>When my TP5s disbonded from trailering I was kicking myself for not having 

>installed a one-piece pipe, but in those early days I was very careful to 

>follow the build instructions precisely. I stll think that a retrofit of a 

>one-piece sleeve  would be more than strong enough to prevent any future 

>disbonding, and would be a relatively easy solution where the TP6s have 

>already disbonded.

>

>As far as the accident goes, we still don't have any real conclusive 

>evidence about the sequence of events. Only a number of theories. Only a 

>wind tunnel test would verify the flutter theory, but who is going to pay 

>for that ? Eyewitness reports can be very misleading.

>If the wing trailing edge pin came off first, is it possible that the 

>pilot was getting set up for landing and deploying flaps and undercarriage 

>?

>

>I also like the other suggested solutions where a lock is put behind the 

>TP12

>Karl

>>

>>

>>

>>Karl,

>>

>>I have attached below, an excerpt of a long mail I sent to the PFA that

>>describes a sequence of events that could lead to the tailplain moving

>>outboard. Out of interest, there is always a gap between the pip-pin and 

>>the

>>face of the rib.

>>

>>This was sent before the current Mod 73 was issued, but you will see why 

>>the

>>temporary remedial action has been to reinforce the pip-pin hole.

>>

>>Nigel

>>

>>

>>

>>

>>-------------------------------

>>Excerpt

>>

>>...... The only thing preventing each tailplane moving sideways is a 

>>single

>>pip-pin that passes through the TP6 bush and into the TP4 torque tube. 

>>(See

>>Fig.5 Chap 4)

>>The design relies on a good bond to hold TP6 in place, however only the

>>protruding outer 12mm (just 8mm on TP5) is required to bond to the 

>>tailplane

>>rib that will subsequently be laid-up onto it. Epoxy adhesive does not 

>>bond

>>well to stainless steel - so the potential for this bondline to fail is

>>great.

>>This tiny bondline is the only "design" load path to prevent the 

>>tailplane

>>moving laterally. If the bond failed, the loose TP6 bush would tend to 

>>push

>>its way inboard into the soft blue foam, allowing the tailplane to move

>>outboard. The TP5 bush would offer no resistance since it would simply 

>>slide

>>along the TP4 torque tube.

>>

>>In some early Europas, this TP6 bush has de-bonded and it is only the

>>laminations into the "PipPin" access hole that prevent any lateral 

>>movement

>>of the tail-plane. This lamination was never intended to be structural. 

>>If

>>the aircraft is high-time and habitually operated off rough strips, it is

>>logical to predict that the continual fretting would cause the glass 

>>around

>>the pip-pin hole to chafe, opening up the hole to a point where the whole

>>tailplane could slide far enough laterally to allow the tail-pane drive 

>>pins

>>(TP12) to disengage from their drive bushes (TP13) - The tailplane would

>>then oscillate violently with catastrophic results.

>>

>>Modification 10672) calls for both the Stainless TP5 and TP6 bushes to be

>>laminated into an epoxy/Bi-Directional Glass tube before inserting this 

>>into

>>the tailplane TP2 cores and laminating the ribs. This bonds both bushes 

>>over

>>their entire surface area, significantly increasing the bond area and 

>>more

>>importantly, physically tying TP5 with TP6 and both the inner and outer 

>>ribs

>>together. With this structure, the entire bond surface area and both ribs

>>would have to fail before the tailplane could move sideways.

>>

>>The loadpath is through the mod 10672 and not through the outer skin and

>>pip-pin hole - a significantly better engineering solution.

>>

>>

>>-

>>

>>

>>

>>

>>

>

>_________________________________________________________________

>Watch all 9 Live Earth concerts live on MSN.  http://liveearth.uk.msn.com

>






	


_________________________________________________________________

Watch all 9 Live Earth concerts live on MSN.  http://liveearth.uk.msn.com

topglock(at)cox.net
Guest

Posted: Sun Jul 15, 2007 1:30 pm Post subject: Europa Tailplane - Mod 73

Karl,



The particulars on aligning and drilling the pip pin holes should not be 

a big problem.  It may be as simple as marking cross hairs on the 

surface of the tailplane or, building a template using a plastic tube 

and end plate, simulating the drive plate, should allow you to get a 

precise enough measurement to drill the holes.  If you've built in a 

drain hole, as provided for in the instructions, the lower hole should 

be a breeze.  At any rate, I see it as a doable mod and one that should 

provide a much stronger tailplane.



Jeff



Karl Heindl wrote:

 	  Quote: 	
		   

 Jeff,



 I think that the TP5 and TP6 can be removed with heat without cutting 

 any holes. Also, it would  be easier to pre-drill the pip-pin holes, 

 as you can then do a trial fit before bonding. To get the position 

 exactly right I would attach a template (using double-sided tape) with 

 a  1/4 inch hole over the top of the recess, first lining up all 3 

 holes with a 1/4 inch shaft or bolt, before removing the TP6. Just one 

 of my crazy ideas.



 Karl



> From: Rman <topglock(at)cox.net>

> Reply-To: europa-list(at)matronics.com

> To: europa-list(at)matronics.com

> Subject: Re: Europa Tailplane - Mod 73

> Date: Sun, 15 Jul 2007 13:25:12 -0500

>

> 

>

> All,

>

> I've read, with great interest, all the suggestions and discussion.  

> I'm no engineer, but I have a pretty good idea of what I would do, 

> should I find any evidence of disbonding of the tailplane bushings.  

> And, I believe it could be done with very little cosmetic damage to 

> the tailplane.  I like the solid tube idea and would build off of 

> that.  Basically, a tube, of the appropriate length, with two 1/4", 

> round, metal rods welded fore and aft, on centerline.  The rods 

> wouldn't have to run the full length of the tube, but it certainly 

> wouldn't hurt.  The purpose of the rods would be to further stabilize 

> the tube and prevent it from twisting.

>

> Should the original bushings become disbonded, it should be a fairly 

> simple task to remove the old bushing (even if it required opening 

> the wingtip), remove the inner bushing and modify the foam and ribs, 

> to accomodate the new shape of the tube.  Inserting the new tube 

> would be as simple as applying a thin coat of Redux to the tube and 

> inner walls of the foam, plugging the outboard end of the new tube 

> and pushing the assembly in.  The new tube would then be drilled to 

> accept the standard pip pins.  Adding covers to the pip pin access 

> holes would further remove the possibility of a pin becoming dislodged.

>

> Seems to me that the new assembly would be extremely strong and 

> should remove any further chance of the tailplanes pulling away from 

> the drive pins.

>

> So, am I way off base, of does this idea hold water?

>

> Jeff - Baby Blue

> 300 hours and finishing up her 2nd annual...

>

> Karl Heindl wrote:

>> 

>>

>>

>>

>>

>> Nigel,

>>

>> I understand all that and your mod should have been made standard a 

>> long time ago. But what about older Europas ? We hear reports about 

>> disbonded TP6s but we don't hear how they were repaired. I really 

>> would like to know. A suitable retrofit mod should also have been 

>> made available as soon as this problem was known.

>> I still say that there is no way the tailplane can move if the pip 

>> pin head is firmly against solid material on the inboard side. You 

>> say there is always a gap, but that gap is filled with floxed epoxy, 

>> and the head is inside a close fitting plastic pipe in my case. I 

>> think another builder recently told us about a similar mod he made. 

>> The remaining space around the pipe is also filled with epoxy. Of 

>> course all these solutions are based on theory and only a lab test 

>> could verify the claims.

>> When my TP5s disbonded from trailering I was kicking myself for not 

>> having installed a one-piece pipe, but in those early days I was 

>> very careful to follow the build instructions precisely. I stll 

>> think that a retrofit of a one-piece sleeve  would be more than 

>> strong enough to prevent any future disbonding, and would be a 

>> relatively easy solution where the TP6s have already disbonded.

>>

>> As far as the accident goes, we still don't have any real conclusive 

>> evidence about the sequence of events. Only a number of theories. 

>> Only a wind tunnel test would verify the flutter theory, but who is 

>> going to pay for that ? Eyewitness reports can be very misleading.

>> If the wing trailing edge pin came off first, is it possible that 

>> the pilot was getting set up for landing and deploying flaps and 

>> undercarriage ?

>>

>> I also like the other suggested solutions where a lock is put behind 

>> the TP12

>>

>>

>> Karl

>>

>>

>>>

>>>

>>>

>>> Karl,

>>>

>>> I have attached below, an excerpt of a long mail I sent to the PFA 

>>> that

>>> describes a sequence of events that could lead to the tailplain moving

>>> outboard. Out of interest, there is always a gap between the 

>>> pip-pin and the

>>> face of the rib.

>>>

>>> This was sent before the current Mod 73 was issued, but you will 

>>> see why the

>>> temporary remedial action has been to reinforce the pip-pin hole.

>>>

>>> Nigel

>>>

>>>

>>>

>>>

>>> -------------------------------

>>> Excerpt

>>>

>>> ...... The only thing preventing each tailplane moving sideways is 

>>> a single

>>> pip-pin that passes through the TP6 bush and into the TP4 torque 

>>> tube. (See

>>> Fig.5 Chap 4)

>>> The design relies on a good bond to hold TP6 in place, however only 

>>> the

>>> protruding outer 12mm (just 8mm on TP5) is required to bond to the 

>>> tailplane

>>> rib that will subsequently be laid-up onto it. Epoxy adhesive does 

>>> not bond

>>> well to stainless steel - so the potential for this bondline to 

>>> fail is

>>> great.

>>> This tiny bondline is the only "design" load path to prevent the 

>>> tailplane

>>> moving laterally. If the bond failed, the loose TP6 bush would tend 

>>> to push

>>> its way inboard into the soft blue foam, allowing the tailplane to 

>>> move

>>> outboard. The TP5 bush would offer no resistance since it would 

>>> simply slide

>>> along the TP4 torque tube.

>>>

>>> In some early Europas, this TP6 bush has de-bonded and it is only the

>>> laminations into the "PipPin" access hole that prevent any lateral 

>>> movement

>>> of the tail-plane. This lamination was never intended to be 

>>> structural. If

>>> the aircraft is high-time and habitually operated off rough strips, 

>>> it is

>>> logical to predict that the continual fretting would cause the 

>>> glass around

>>> the pip-pin hole to chafe, opening up the hole to a point where the 

>>> whole

>>> tailplane could slide far enough laterally to allow the tail-pane 

>>> drive pins

>>> (TP12) to disengage from their drive bushes (TP13) - The tailplane 

>>> would

>>> then oscillate violently with catastrophic results.

>>>

>>> Modification 10672) calls for both the Stainless TP5 and TP6 bushes 

>>> to be

>>> laminated into an epoxy/Bi-Directional Glass tube before inserting 

>>> this into

>>> the tailplane TP2 cores and laminating the ribs. This bonds both 

>>> bushes over

>>> their entire surface area, significantly increasing the bond area 

>>> and more

>>> importantly, physically tying TP5 with TP6 and both the inner and 

>>> outer ribs

>>> together. With this structure, the entire bond surface area and 

>>> both ribs

>>> would have to fail before the tailplane could move sideways.

>>>

>>> The loadpath is through the mod 10672 and not through the outer 

>>> skin and

>>> pip-pin hole - a significantly better engineering solution.

>>>

>>>

>>> -

>>>

>>>

>>>

>>>

>>>

>>

>> _________________________________________________________________

>> Watch all 9 Live Earth concerts live on MSN.  

>> http://liveearth.uk.msn.com

>>

>>

>>

>>

>>

>>

>>

>

>



 _________________________________________________________________

 Watch all 9 Live Earth concerts live on MSN.  http://liveearth.uk.msn.com

gcrowder2

Joined: 09 Jan 2006
Posts: 136
Location: Golden, Colorado USA

Posted: Sun Jul 15, 2007 1:57 pm Post subject: Europa Tailplane - Mod 73

Yes, thats all correct.  The downforce of the tail just perfectly balances the CG being in front of the Aerodynamic Center.  That creates a stable pitch attitude.  Actually the negative CM of the wing is one of the factors that determine the Aerodynamic Center.  Once the tail is gone, the aerodynamic center of the entire aircraft will move back to the wings center of pressure, which is behind the CG causing the aircraft to pitch nose down.  At the same time, the CG has moved forward since 20 lbs on the tail is now missing.  Bad JuJu.  The tail was creating a positive CM, which is no longer there.  If the tail is normally creating downforce, then losing that downforce will cause the plane to pitch down.  Just think what happens when you push the stick forward.  You are lessening the downforce on the tail, which causes the aircraft to pitch down.

                                            Glenn

   From: mikenjulie.parkin(at)btinternet.com

To: europa-list(at)matronics.com

Subject: Re: Europa Tailplane - Mod 73

Date: Sun, 15 Jul 2007 21:24:08 +0100

   .ExternalClass P {padding-right:0px;padding-left:0px;padding-bottom:0px;padding-top:0px;} .ExternalClass {font-size:10pt;font-family:Tahoma;}  

 [quote] Glen and Ron P.

 I am a pilot and not an aerodynamicist.  However, having just blown off the dust from my old aerodynamics textbook, what you are saying is not strictly correct.  It may be that you are correct with relevance to the europa, but it really does depend on where the C of G is!!

 If one considers the main wing, if the Aerodynamic Centre (AC) is aft of the CofG the wing would be in a stable configuration. That is without any opposing forces the aircraft would pitch down.  On the other hand, if the AC was forward of the CofG without any opposing forces the aircraft would pitch up.

 As the stabiliser is well aft of the aircraft CofG it is always stabilising.  But it is possible to have a de-stabilising wing with a stabilising tailplane.  Overall the aircraft would be stable as long as sum of wing and tailplane Cm/Cl curves have a negative slope.

 The point is that if the wing AC is forward of the CofG with no other forces affecting it the aircraft will pitch up, not down.

 Most aeroplanes I have flown 'balloon' on flap selection, particularly with the first notch of flap.  However the nose down effect of selecting flap is caused by a rearward movement of the Centre of Pressure which creates an increased moment about the C of G which requires the adjustment of the tailplane trim - all be it with a slightly increased nose down attitude.  Much the same I suppose as saying the pitch down is caused by an increase in negative Cm.

 Having said all that looking at the diagram in the aircraft handbook in the weight and balance chapter as a rough guestimate it would appear that the C of G of our europas (58-62.5in AOD) would always be forward of the Aerodynamic Centre which is approximately 25% chord in subsonic flow.

 regards,

 Mike.

 [quote] ---

kheindl(at)msn.com
Guest

Posted: Sun Jul 15, 2007 3:10 pm Post subject: Europa Tailplane - Mod 73

Hi Jeff,



I think we are basically in agreement. But pre-drilling the holes in my view 

is absolutely essential.

If you make a tiny mistake in drilling after the installation you will have 

to start all over again, and you won't have a 100% accurate reference for 

the holes and angle.



Regards,



Karl





 	  Quote: 	
		  From: Jeff B <topglock(at)cox.net>

Reply-To: europa-list(at)matronics.com

To: europa-list(at)matronics.com

Subject: Re: Europa Tailplane - Mod 73

Date: Sun, 15 Jul 2007 16:25:18 -0500






Karl,



The particulars on aligning and drilling the pip pin holes should not be a 

big problem.  It may be as simple as marking cross hairs on the surface of 

the tailplane or, building a template using a plastic tube and end plate, 

simulating the drive plate, should allow you to get a precise enough 

measurement to drill the holes.  If you've built in a drain hole, as 

provided for in the instructions, the lower hole should be a breeze.  At 

any rate, I see it as a doable mod and one that should provide a much 

stronger tailplane.



Jeff



Karl Heindl wrote:

>

>Jeff,

>

>I think that the TP5 and TP6 can be removed with heat without cutting any 

>holes. Also, it would  be easier to pre-drill the pip-pin holes, as you 

>can then do a trial fit before bonding. To get the position exactly right 

>I would attach a template (using double-sided tape) with a  1/4 inch hole 

>over the top of the recess, first lining up all 3 holes with a 1/4 inch 

>shaft or bolt, before removing the TP6. Just one of my crazy ideas.

>

>Karl

>

>>From: Rman <topglock(at)cox.net>

>>Reply-To: europa-list(at)matronics.com

>>To: europa-list(at)matronics.com

>>Subject: Re: Europa Tailplane - Mod 73

>>Date: Sun, 15 Jul 2007 13:25:12 -0500

>>

>>

>>

>>All,

>>

>>I've read, with great interest, all the suggestions and discussion.  I'm 

>>no engineer, but I have a pretty good idea of what I would do, should I 

>>find any evidence of disbonding of the tailplane bushings.  And, I 

>>believe it could be done with very little cosmetic damage to the 

>>tailplane.  I like the solid tube idea and would build off of that.  

>>Basically, a tube, of the appropriate length, with two 1/4", round, metal 

>>rods welded fore and aft, on centerline.  The rods wouldn't have to run 

>>the full length of the tube, but it certainly wouldn't hurt.  The purpose 

>>of the rods would be to further stabilize the tube and prevent it from 

>>twisting.

>>

>>Should the original bushings become disbonded, it should be a fairly 

>>simple task to remove the old bushing (even if it required opening the 

>>wingtip), remove the inner bushing and modify the foam and ribs, to 

>>accomodate the new shape of the tube.  Inserting the new tube would be as 

>>simple as applying a thin coat of Redux to the tube and inner walls of 

>>the foam, plugging the outboard end of the new tube and pushing the 

>>assembly in.  The new tube would then be drilled to accept the standard 

>>pip pins.  Adding covers to the pip pin access holes would further remove 

>>the possibility of a pin becoming dislodged.

>>

>>Seems to me that the new assembly would be extremely strong and should 

>>remove any further chance of the tailplanes pulling away from the drive 

>>pins.

>>

>>So, am I way off base, of does this idea hold water?

>>

>>Jeff - Baby Blue

>>300 hours and finishing up her 2nd annual...

>>

>>Karl Heindl wrote:

>>>

>>>

>>>

>>>

>>>

>>>Nigel,

>>>

>>>I understand all that and your mod should have been made standard a long 

>>>time ago. But what about older Europas ? We hear reports about disbonded 

>>>TP6s but we don't hear how they were repaired. I really would like to 

>>>know. A suitable retrofit mod should also have been made available as 

>>>soon as this problem was known.

>>>I still say that there is no way the tailplane can move if the pip pin 

>>>head is firmly against solid material on the inboard side. You say there 

>>>is always a gap, but that gap is filled with floxed epoxy, and the head 

>>>is inside a close fitting plastic pipe in my case. I think another 

>>>builder recently told us about a similar mod he made. The remaining 

>>>space around the pipe is also filled with epoxy. Of course all these 

>>>solutions are based on theory and only a lab test could verify the 

>>>claims.

>>>When my TP5s disbonded from trailering I was kicking myself for not 

>>>having installed a one-piece pipe, but in those early days I was very 

>>>careful to follow the build instructions precisely. I stll think that a 

>>>retrofit of a one-piece sleeve  would be more than strong enough to 

>>>prevent any future disbonding, and would be a relatively easy solution 

>>>where the TP6s have already disbonded.

>>>

>>>As far as the accident goes, we still don't have any real conclusive 

>>>evidence about the sequence of events. Only a number of theories. Only a 

>>>wind tunnel test would verify the flutter theory, but who is going to 

>>>pay for that ? Eyewitness reports can be very misleading.

>>>If the wing trailing edge pin came off first, is it possible that the 

>>>pilot was getting set up for landing and deploying flaps and 

>>>undercarriage ?

>>>

>>>I also like the other suggested solutions where a lock is put behind the 

>>>TP12

>>>

>>>

>>>Karl

>>>

>>>

>>>>

>>>>

>>>>

>>>>Karl,

>>>>

>>>>I have attached below, an excerpt of a long mail I sent to the PFA that

>>>>describes a sequence of events that could lead to the tailplain moving

>>>>outboard. Out of interest, there is always a gap between the pip-pin 

>>>>and the

>>>>face of the rib.

>>>>

>>>>This was sent before the current Mod 73 was issued, but you will see 

>>>>why the

>>>>temporary remedial action has been to reinforce the pip-pin hole.

>>>>

>>>>Nigel

>>>>

>>>>

>>>>

>>>>

>>>>-------------------------------

>>>>Excerpt

>>>>

>>>>...... The only thing preventing each tailplane moving sideways is a 

>>>>single

>>>>pip-pin that passes through the TP6 bush and into the TP4 torque tube. 

>>>>(See

>>>>Fig.5 Chap 4)

>>>>The design relies on a good bond to hold TP6 in place, however only the

>>>>protruding outer 12mm (just 8mm on TP5) is required to bond to the 

>>>>tailplane

>>>>rib that will subsequently be laid-up onto it. Epoxy adhesive does not 

>>>>bond

>>>>well to stainless steel - so the potential for this bondline to fail is

>>>>great.

>>>>This tiny bondline is the only "design" load path to prevent the 

>>>>tailplane

>>>>moving laterally. If the bond failed, the loose TP6 bush would tend to 

>>>>push

>>>>its way inboard into the soft blue foam, allowing the tailplane to move

>>>>outboard. The TP5 bush would offer no resistance since it would simply 

>>>>slide

>>>>along the TP4 torque tube.

>>>>

>>>>In some early Europas, this TP6 bush has de-bonded and it is only the

>>>>laminations into the "PipPin" access hole that prevent any lateral 

>>>>movement

>>>>of the tail-plane. This lamination was never intended to be structural. 

>>>>If

>>>>the aircraft is high-time and habitually operated off rough strips, it 

>>>>is

>>>>logical to predict that the continual fretting would cause the glass 

>>>>around

>>>>the pip-pin hole to chafe, opening up the hole to a point where the 

>>>>whole

>>>>tailplane could slide far enough laterally to allow the tail-pane drive 

>>>>pins

>>>>(TP12) to disengage from their drive bushes (TP13) - The tailplane 

>>>>would

>>>>then oscillate violently with catastrophic results.

>>>>

>>>>Modification 10672) calls for both the Stainless TP5 and TP6 bushes to 

>>>>be

>>>>laminated into an epoxy/Bi-Directional Glass tube before inserting this 

>>>>into

>>>>the tailplane TP2 cores and laminating the ribs. This bonds both bushes 

>>>>over

>>>>their entire surface area, significantly increasing the bond area and 

>>>>more

>>>>importantly, physically tying TP5 with TP6 and both the inner and outer 

>>>>ribs

>>>>together. With this structure, the entire bond surface area and both 

>>>>ribs

>>>>would have to fail before the tailplane could move sideways.

>>>>

>>>>The loadpath is through the mod 10672 and not through the outer skin 

>>>>and

>>>>pip-pin hole - a significantly better engineering solution.

>>>>

>>>>

>>>>-

>>>>

>>>>

>>>>

>>>>

>>>>

>>>

>>>_________________________________________________________________

>>>Watch all 9 Live Earth concerts live on MSN.  

>>>http://liveearth.uk.msn.com

>>>

>>>

>>>

>>>

>>>

>>>

>>>

>>

>>

>>

>>

>

>_________________________________________________________________

>Watch all 9 Live Earth concerts live on MSN.  http://liveearth.uk.msn.com

>






	


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grahamsingleton(at)btinte
Guest

Posted: Sun Jul 15, 2007 4:09 pm Post subject: Europa Tailplane - Mod 73

Karl

you might get the TP5 out with heat but the TP6 is not so easy. Even 

after it is loose from the end rib you then have to get it inserted into 

the root rib and then get it out of that.

The heat to loosen it from the end rib will almost certainly melt the 

foam to an unknown extent, not worth the risk.

Graham



Karl Heindl wrote:

 	  Quote: 	
		   

 

 

 Jeff,

 

 I think that the TP5 and TP6 can be removed with heat without cutting 

 any holes. Also, it would  be easier to pre-drill the pip-pin holes, as 

 you can then do a trial fit before bonding. To get the position exactly 

 right I would attach a template (using double-sided tape) with a  1/4 

 inch hole over the top of the recess, first lining up all 3 holes with a 

 1/4 inch shaft or bolt, before removing the TP6. Just one of my crazy 

 ideas.

 

 Karl

grahamsingleton(at)btinte
Guest

Posted: Sun Jul 15, 2007 4:14 pm Post subject: Europa Tailplane - Mod 73

Glenn

lowering the flaps gently at a trimmed 80 kts should result in a trimmed 

60 kts without needing to adjust the trim.

I remember Ivan was delighted to discover this early in the testing and 

bought Don Dykins a pint or two to celebrate!

Don was gracious and put it down to luck.

Graham.



glenn crowder wrote:

 	  Quote: 	
		   Hi Mike - yes the aircraft will always pitch down with a non symmetrical 

 airfoil.  This is why

 aerobatic aircraft are designed with symmetrical airfoils - zero 

 pitching moment. 

 Aerobatic pilots don't like their aircraft pitching without their command!

   Also, in the accident aircraft, losing the tailplane suddenly removed 

 20 lbs of weight off the

 tail, pitching the nose down further.

   If you've ever flown a C-172 while lowering the flaps you will 

 probably remember the

 pitch down.  Actually, it balloons up first while speed is being lost, 

 then pitches down.

   The wing is now very non-symmetrical, requiring up trim on the elevator to

 balance the increased negative CM.  The Europa does this too but not as 

 noticeable,

 probably because of the powerful tail.

  

                                             Glenn

  

                                                    

  

                                             

 

 

 

     ------------------------------------------------------------------------

     From: mikenjulie.parkin(at)btinternet.com

     To: europa-list(at)matronics.com

     Subject: Re: Europa Tailplane - Mod 73

     Date: Sun, 15 Jul 2007 10:01:17 +0100

 

     I accept what you say about CM about the aerodynamic centre for an

     aerofoil.  But are you saying that irrespective of the CofG of the

     aircraft, an aircraft will always pitch down.

      

     regards,

      

     Mike

      

      

 

 *

 

 arget=_blank>http://www.matronics.com/Navigator?Europa-List

 p://forums.matronics.com

 

 *

 

 

 ------------------------------------------------------------------------

 See what you’re getting into…before you go there. Check it out! 

 <http://newlivehotmail.com>

 

 *

 

 

 *


	


-- 

Graham Singleton



Tel: +441629820187

Mob: +447739582005

kheindl(at)msn.com
Guest

Posted: Sun Jul 15, 2007 4:36 pm Post subject: Europa Tailplane - Mod 73

Graham,



I could be wrong, but I don't agree. I think I can control the heat 

precisely to a localized area and not damage any foam.



Karl





 	  Quote: 	
		  From: Graham Singleton <grahamsingleton(at)btinternet.com>

Reply-To: europa-list(at)matronics.com

To: europa-list(at)matronics.com

Subject: Re: Europa Tailplane - Mod 73

Date: Mon, 16 Jul 2007 01:11:29 +0100




<grahamsingleton(at)btinternet.com>



Karl

you might get the TP5 out with heat but the TP6 is not so easy. Even after 

it is loose from the end rib you then have to get it inserted into the root 

rib and then get it out of that.

The heat to loosen it from the end rib will almost certainly melt the foam 

to an unknown extent, not worth the risk.

Graham



Karl Heindl wrote:

>

>Jeff,

>

>I think that the TP5 and TP6 can be removed with heat without cutting any 

>holes. Also, it would  be easier to pre-drill the pip-pin holes, as you 

>can then do a trial fit before bonding. To get the position exactly right 

>I would attach a template (using double-sided tape) with a  1/4 inch hole 

>over the top of the recess, first lining up all 3 holes with a 1/4 inch 

>shaft or bolt, before removing the TP6. Just one of my crazy ideas.

>

>Karl






	


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ptag.dev(at)tiscali.co.uk
Guest

Posted: Mon Jul 16, 2007 12:01 am Post subject: Europa Tailplane - Mod 73

Karl

IMHO You are dicing with trouble!

You will find that One of the main problems will be that the foam will

expand considerably where the heat is (the rest of the unheated foam

acts as a thermal insulator ) so you will get differential expansion on

a grand scale meaning considerable buckling.  Been there done that!

The only chance of applying any heat anywhere will be by gradual heat

sink over many hours and over the whole item and then similarly cooling

over many hours as post curing was required on the original build.



Regards

Bob Harrison  G-PTAG 

--

kheindl(at)msn.com
Guest

Posted: Mon Jul 16, 2007 3:59 am Post subject: Europa Tailplane - Mod 73

Hi Bob,



Thanks for the warning. But, a) I have no intention of doing anything to my 

tailplanes for quite a while, while all the dust settles. I am quite happy 

with my tailplane retention the way it is right now.

b) I would have no problem heating the TP6 gradually with precise 

temperature control, and in any case I would do a trial run on a separate 

prepared piece of foam.



Now Fred Klein wants to implement another good mod, but I think the PFA has 

already stated that pre-skinned tailplanes are not affected.



Regards,



Karl





[quote]From: "R.C.Harrison" <ptag.dev(at)tiscali.co.uk>

Reply-To: europa-list(at)matronics.com

To: <europa-list(at)matronics.com>

Subject: RE: Europa Tailplane - Mod 73

Date: Mon, 16 Jul 2007 08:59:23 +0100






Karl

IMHO You are dicing with trouble!

You will find that One of the main problems will be that the foam will

expand considerably where the heat is (the rest of the unheated foam

acts as a thermal insulator ) so you will get differential expansion on

a grand scale meaning considerable buckling.  Been there done that!

The only chance of applying any heat anywhere will be by gradual heat

sink over many hours and over the whole item and then similarly cooling

over many hours as post curing was required on the original build.



Regards

Bob Harrison  G-PTAG

--

grahamsingleton(at)btinte
Guest

Posted: Mon Jul 16, 2007 8:17 am Post subject: Europa Tailplane - Mod 73

Hard to believe that, Karl. You will still have difficulty with the TP6, 

getting it entered into the TP5 hole

Graham



Karl Heindl wrote:

 	  Quote: 	
		   

 

 

 Graham,

 

 I could be wrong, but I don't agree. I think I can control the heat 

 precisely to a localized area and not damage any foam.

 

 Karl

willie.harrison(at)tinyon
Guest

Posted: Mon Jul 16, 2007 8:37 am Post subject: Europa Tailplane - Mod 73

Roger at the Factory confirmed that Jeremy is correct.

On 16 Jul 2007, at 13:31, Jeremy Davey wrote:



 	  Quote: 	
		   

 <europaflyer_3(at)msn.com>



 Karl,



 Sorry to differ, but I believe that's not so. Pre-skinned  

 tailplanes ARE

 affected - the only ones that are possibly not affected are the pre- 

 moulded

 ones, and to the best of my knowledge there are only two sets of  

 those: on

 Peter Kember's new bird, and on the old factory demonstrator G-GBXS.



 Has anyone come up with a reason for overlapping the lower skin  

 instead of

 using a flox corner yet?

nigel_graham(at)btclick.c
Guest

Posted: Mon Jul 16, 2007 8:37 am Post subject: Europa Tailplane - Mod 73

Karl



I think that when the cause is eventually discovered - it will be found to

be a combination of two or more conditions that individually, would not

cause a problem.

One Pip-Pin was found to be bent through 90 degrees, implying that one

tailplane did rotate and that TP4 remained in place. I would guess that the

TP6 remained firmly anchored to the torque tube by the pin and the rest of

the structure broke loose and rotated around it.



A few years back I witnessed a formula one fatal at Reno, right in front of

our grandstand. The aircraft suffered a tailplane flutter which resulted in

four or five violent pitch up/down cycles before the tail broke free and the

aircraft pitched into the ground. The whole incident probably took no more

than 2.5 seconds from start to sad end. The torsional load on the main wing

spars must have been phenomenal and it would be easy to understand how a

main plane could fail following a tailplane flutter.



With regard to suitable repairs. I have thought long and hard about this

(and so are the guys at the PFA) and the truth is that there is no quick

fix. Regardless of whatever method is devised to locate the tail laterally,

the fact remains that a disbonded TP5 and TP6 will prevent the tailplane

locating accurately on TP4 - and this must be addressed.

The Mod 73 Pip-pin reinforcement is a good short term fix (the sticking

plaster).



To retro-fit the tailplane mod would require that the entire tailplane be

dismantled and rebuilt .....possible, but by no means easy.

In my opinion it would be easier to build new tailplanes (and if I was in

this predicament, this would be my chosen course of action).

I quite enjoyed building mine and it didn't take that long.



How about someone (Europa 2004?) producing new tail kits (Tailplanes only)

and offer these to existing Europa owners at cost plus. I reckon they could

be produced for around £400-£500 GPB ($800-$1000 USD) plus shipping. It's an

idea to keep the discussion rolling......



Nigel

--

kheindl(at)msn.com
Guest

Posted: Mon Jul 16, 2007 9:46 am Post subject: Europa Tailplane - Mod 73

Is there anything special about the TP5 hole ? The TP5 would be removed 

first,  obviously.

Karl

 	  Quote: 	
		  From: Graham Singleton <grahamsingleton(at)btinternet.com>

Reply-To: europa-list(at)matronics.com

To: europa-list(at)matronics.com

Subject: Re: Europa Tailplane - Mod 73

Date: Mon, 16 Jul 2007 17:18:01 +0100

<grahamsingleton(at)btinternet.com>

Hard to believe that, Karl. You will still have difficulty with the TP6, 

getting it entered into the TP5 hole

Graham

Karl Heindl wrote:

>

>Graham,

>

>I could be wrong, but I don't agree. I think I can control the heat 

>precisely to a localized area and not damage any foam.

>

>Karl

>

_________________________________________________________________

Watch all 9 Live Earth concerts live on MSN.  http://liveearth.uk.msn.com

grahamsingleton(at)btinte
Guest

Posted: Mon Jul 16, 2007 10:02 am Post subject: Europa Tailplane - Mod 73

Glenn

the Europa airfoil as designed has a bit of reflex in the trailing edge 

but you need to check the computer printout to see it.

Graham



glenn crowder wrote:

 	  Quote: 	
		     All non symmetrical airfoils that do not have reflex in the trailing 

 edge have a negative CM (pitching moment).  

  

                                                  Glenn

  

 ------------------------------------------------------------------------

grahamsingleton(at)btinte
Guest

Posted: Mon Jul 16, 2007 3:29 pm Post subject: Europa Tailplane - Mod 73

No but its a tight fit on the bush, TP5 o6 TP6. How do you persuade it 

to start down the hole from the inside?

Graham



Karl Heindl wrote:

 	  Quote: 	
		   

 

 

 Is there anything special about the TP5 hole ? The TP5 would be removed 

 first,  obviously.

 

 Karl

kheindl(at)msn.com
Guest

Posted: Mon Jul 16, 2007 4:26 pm Post subject: Europa Tailplane - Mod 73

Graham,



Not sure what you mean by the bush.

Disregarding the heat application for the time being, I would have a 1.5" 

alu tube inside the TP6.

Then I would drill a small hole near the pip pin hole through the TP6 and 

into the tube for a small self-tapping screw or rivet, if there is space for 

a rivet tool in the recess. Assuming, the TP6 is now loose, I take hold of 

the tube end at the root and slowly pull the thing out with a turning 

motion.

The screw head (unless it is countersunk) will cut a fine spiralshaped 

groove into the foam, but that is hardly a problem, because I would line the 

hole with floxed redux anyway before inserting the new part. Does that make 

sense so far ?

Actually, the screw would already be in before I start the heat application, 

because the TP6 needs to be turned once the adhesive starts to soften, and 

would have to keep turning while the adhesive cools down again before 

extraction.

Karl



 	  Quote: 	
		  From: Graham Singleton <grahamsingleton(at)btinternet.com>

Reply-To: europa-list(at)matronics.com

To: europa-list(at)matronics.com

Subject: Re: Europa Tailplane - Mod 73

Date: Tue, 17 Jul 2007 00:32:32 +0100




<grahamsingleton(at)btinternet.com>



No but its a tight fit on the bush, TP5 o6 TP6. How do you persuade it to 

start down the hole from the inside?

Graham



Karl Heindl wrote:

>

>Is there anything special about the TP5 hole ? The TP5 would be removed 

>first,  obviously.

>

>Karl






	


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mikenjulie.parkin(at)btin
Guest

Posted: Mon Jul 16, 2007 9:30 pm Post subject: Europa Tailplane - Mod 73

Nigel,



Unpopular as it may be, I think you are right.  Mod 73 strikes me as a very 

unsatisfactory fix for a poor design.  What I would like to see is a new set 

of tailplanes with a redesigned torque shaft and retention system.  A 'belt 

and braces' system that will make all this uncertainty go away.  We all love 

our little aeroplanes, but it must be made more rugged down the back.  At 

the moment the whole situation concerns me greatly and my confidence in the 

integrity of the aircraft has taken a severe knock with the loss of G-HOFC 

and our friends.  Accidents caused by pilot error I can live with, but 

structural failure I cannot.  I want to be able to relax when I fly my 

Europa.



Europa 2004 can put on the list now for a new set of tailplanes if the 

re-design can restore my confidence in my aircraft.



regards,



Mike



 	  Quote: 	
		   How about someone (Europa 2004?) producing new tail kits (Tailplanes only)

 and offer these to existing Europa owners at cost plus. I reckon they 

 could

 be produced for around £400-£500 GPB ($800-$1000 USD) plus shipping. It's 

 an

 idea to keep the discussion rolling......



 Nigel

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