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Mod 72 question

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rlborger(at)mac.com
Guest

Posted: Fri Jan 19, 2007 5:48 am Post subject: Mod 72 question

Fellow Europaphiles,



The Mod 72 topic has become too quiet.  I've decided to give it a poke and see if I can wake it up again.



I have all the various bits for Mod 72 on order.  Etching primer, ACF-50, 16.5 mm hand reamer & Mod 72 kit.



I am wondering why the heavy wall tubing is not bonded in place with something like Redux.



Is the press fit good enough to support the frame?



Would it be better to Redux the insert in place?  Better support and corrosion protection?



If not, why not?



Good building and great flying,

Bob Borger

Standing by, wearing my nomex undies, ready for the flames.



P.S.

The reamer will be available for loan to any Europa builder in the U.S. or Canada who needs it for Mod 72.

wdaniell(at)etb.net.co
Guest

Posted: Fri Jan 19, 2007 6:25 am Post subject: Mod 72 question

I had the same question...



--

peterz(at)zutrasoft.com
Guest

Posted: Fri Jan 19, 2007 7:01 am Post subject: Mod 72 question

.... I think many of us do as well.....

 

Has anyone heard the answer from the factory?

 

Cheers,

Pete

 



	--

robh(at)hyperion-ef.com
Guest

Posted: Fri Jan 19, 2007 8:11 am Post subject: Mod 72 question

Mod 72 provides added strength, in particular in bending, by adding

thickness to the wall of the tube.  It is the added thickness that provides

the additional strength and because there are no forces that would tend to

move the insert along its axis (relative to the original tubing) there is no

need for bonding it into the frame.



Epoxy used to create a bond between the original tube and the insert would

be a weak annular region that could allow the original tube to deform,

albeit very slightly, if the epoxy were to extrude out of the gap.



As for corrosion protection, remember that the original frame is powder

coated only on the exterior so nothing much changes when adding the insert.

Best regards,



Rob Housman

A070

Airframe complete

Irvine, CA



--

jeff(at)rmmm.net
Guest

Posted: Fri Jan 19, 2007 9:04 am Post subject: Mod 72 question

The way I'm interpreting the need for this mod, is that it is only for 

914's or 912-S Europas with props heaver than 25 lb's is that correct? 

Are their those that feel and is there a reason they feel mod 72 should 

be placed on all Europas?

Jeff

N128LJ / Gold Rush



On Jan 19, 2007, at 9:56 AM, Rob Housman wrote:



[quote] 



 Mod 72 provides added strength, in particular in bending, by adding

 thickness to the wall of the tube.  It is the added thickness that 

 provides

 the additional strength and because there are no forces that would 

 tend to

 move the insert along its axis (relative to the original tubing) there 

 is no

 need for bonding it into the frame.



 Epoxy used to create a bond between the original tube and the insert 

 would

 be a weak annular region that could allow the original tube to deform,

 albeit very slightly, if the epoxy were to extrude out of the gap.



 As for corrosion protection, remember that the original frame is powder

 coated only on the exterior so nothing much changes when adding the 

 insert.

 Best regards,



 Rob Housman

 A070

 Airframe complete

 Irvine, CA



 --

steven.pitt2(at)ntlworld.
Guest

Posted: Fri Jan 19, 2007 11:39 am Post subject: Mod 72 question

To all Europa owners/builders from a UK owner/now Flyer.

You may not get much out of the UK builders/owners this weekend as the Club 

is having its annual away weekend including John and Roger (I believe) from 

the factory.

As a 912S trigear owner I am affected by the Mod 72 and have ordered my 

parts as directed by the Europa (2004) website.

I am not an expert on the subject but understand from listening to 

intelligent conversations that the mod is mandatory where stated in the 

Europa site but advisable for others. Whether you do the Mod will depend on 

your Governing Authorities, technical understanding of the issues or your 

wish to provide 'belt and braces' to your aircraft.

For those that have not visited the Europa 2004 website recently might I 

suggest you do so as the sad news of the recent death of one of the key 

personalities in the company might help the understanding of communication 

issues.

To all of you I wish you a Happy and Successful year whether flying or 

building your craft.

Steve Pitt G-SMDH

PS see you all at Sun'n'Fun.

PPS I hope I do not mislead anyone with this message - I am sure those with 

more technical expertise will correct me if required.

roger(at)middlecave.plus.
Guest

Posted: Fri Jan 19, 2007 12:43 pm Post subject: Mod 72 question

O.K. Bob, you woke me up!

Rob Housman's answer is on the ball.  Using Redux would necessitate

increasing the clearance between the original tube and the new inserts.  The

Redux would not be strong enough to withstand the bending load, which is the

critical part of the overall stress.  The insert is intended to be a close

but not interference fit in the outer tubes after reaming.  Any small

clearance which may exist after fitting the new tubes will be taken up by

deflection caused by the initial load applied by the weight of the engine

and propeller.



The bending load is applied both by the vertical load from the weight of the

engine acting some 2.5" approx forward of the weld affected area, and also

by the small tube which is about 1" above the main horizontal tube. The

forward thrust from the propeller creates this bending load.  To that has to

be added on one side the torque reaction. (Distances are from memory as I am

writing this fom home).



I have made a small change to the Mod leaflet to make the applicability

criteria a little clearer.  The factors which affect applicability are

engine and propeller weights and c's of g forward of the undercarriage

mounting frame, and the engine torque.



Briefly all Rotax engined Europas, except those with classic engine

installations and light propellers as defined in the Mod leaflet, will need

to incorporate the Mod.  So all Rotax engined XS models, regardless of

whether 912, 912S or 914, and regardless of propeller will need the Mod.

Europas with engines other than Rotax will need to be checked on a case by

case basis.  We have already established that Europas with the Jabiru 3300

engine will need the Mod.



It was orginally intended that the news of the Mod would be promulgated by

the PFA and EA4 on their respective websites simultaneously - unfortunately

that did not happen.  The PFA have now updated their Type Acceptance Data

Sheet to include Mod 72.



We realise that quite a long time has elapsed since the failure took place

that gave rise to this Mod. It was necessary first to establish that the

failure was not a one-off due to a unique set of circumstances; research

into the original calculations established that there was a more general

problem.  The we had to devise a satisfactory solution that would be

reasonably straightforward to incorporate, then carry out tests to prove the

fix.  Then the method had to be agreed with the PFA, and the Mod leaflet

written.  This latter exercise proved rather drawn out, and several drafts

were needed before the current version was agreed.  Establishing why the

original error in stressing was made during the reign of EMIL proved almost

impossible, as the engineer concerned died a few years ago.



I realise that many people may feel that an unnecessary fuss is being made

about this Mod, but a look at the attached photo of the first, but not only,

failure should prove interesting.



Best regards,



Roger Bull

EA4



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Gary.Leinberger(at)miller
Guest

Posted: Fri Jan 19, 2007 1:39 pm Post subject: Mod 72 question

What about the bottom weld points? Would it hurt to put in pieces here

also?

Gary leinberger

A237 



--

rlborger(at)mac.com
Guest

Posted: Fri Jan 19, 2007 2:26 pm Post subject: Mod 72 question

Roger,

Thanks for the detailed explanation.  I appreciate it very much.



Best regards,

Bob Borger

Europa Kit #A221 N914XL, XS Mono, Intercooled 914, Airmaster C/S

http://www.europaowners.org/N914XL

(85%) tail kit done, wings closed, cockpit module installed, pitch system in, landing gear frame in, rudder system in, outrigger mod in, Fuselage Top on, lift/drag/flap pins in, wing incidence set, tie bar in, flap drive in, Mod 70 done.  Baggage bay in.  Flaps & Main Gear complete.  Working in - 24 Instrument Panel, 25 Electrical, 30 Fuel System, 32 Tail, 34 Door Latches & 35 Doors, 37 Finishing.  Airmaster arrived 29 Sep 05.  Seat arrived from Oregon Aero.  E04 interior kit has arrived.  Installing the ROTAX 914.

3705 Lynchburg Dr.

Corinth, TX  76208

Home:  940-497-2123

Cel:  817-992-1117

 



 [quote][b]

ami(at)mcfadyean.freeserv
Guest

Posted: Fri Jan 19, 2007 2:39 pm Post subject: Mod 72 question

Note the 'spanner' scratch that appears to have initiated the crack on the 

s'bd-side arm.

Glad that EA4 are now awake!



Duncan McF.

---

roger(at)middlecave.plus.
Guest

Posted: Fri Jan 19, 2007 3:10 pm Post subject: Mod 72 question

Gary,



Not necessary, there are no offset bending loads at the bottom.



Regards,



Roger

--

SPurpura(at)aol.com
Guest

Posted: Fri Jan 19, 2007 5:10 pm Post subject: Mod 72 question

This was with a 914 swinging a 10 pound Whirlwind C.S. prop.I think that the .050 wall tube was a little light.

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grahamsingleton(at)btinte
Guest

Posted: Fri Jan 19, 2007 5:37 pm Post subject: Mod 72 question

Roger

what type of failure was it, bending, shear or fatigue?

Graham



Roger Bull wrote:



 	  Quote: 	
		  O.K. Bob, you woke me up!

Rob Housman's answer is on the ball.  Using Redux would necessitate

increasing the clearance between the original tube and the new inserts.

96victor(at)gmail.com
Guest

Posted: Fri Jan 19, 2007 8:52 pm Post subject: Mod 72 question

Hi Graham

  

 I doubt that you will get an answer what caused the break.  It looks to be that it was most likely a tension break with perhaps some fatigue factor.  The upper tubes will have tension in the upper parts and that will be increased by the thrust.  There also could be some problem with non annealed brittleness from the closeness of the weld. 

  

 The lower tubes should be ok as they have tension stress from weight bearing but that is cancelled by compression.

  

 But then what do I know.  My engineering studies were 50 years ago!  Now I am just a dumb doc.

  

 Tom



 

 On 1/19/07, Graham Singleton <grahamsingleton(at)btinternet.com (grahamsingleton(at)btinternet.com)> wrote: [quote]--> Europa-List message posted by: Graham Singleton < grahamsingleton(at)btinternet.com (grahamsingleton(at)btinternet.com)>



Roger

what type of failure was it, bending, shear or fatigue?

Graham



Roger Bull wrote:



[quote]O.K. Bob, you woke me up!

Rob Housman's answer is on the ball.  Using Redux would necessitate  [quote][b]

pete(at)lawless.info
Guest

Posted: Sat Jan 20, 2007 1:19 am Post subject: Mod 72 question

Morning Roger



Can you tell me how many failures there have been and were they all on the

XS set up?



Just trying to assess how quickly I should plan to do the mod as I think my

Classic is just outside the criteria to make it mandatory.



Regards



Pete Lawless



--

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

Posted: Sat Jan 20, 2007 1:37 am Post subject: Mod 72 question

Hi! Tom  

 This is now two photo’s of failed items I’ve seen which, IMHO I have to agree 100% with you every indication of fatigue is there. My training is likely “old Hat” particularly considering modern alloy extruded tube but  I wonder what traceability exists of annealing/stress relieving :-  

a)  done to these and all frames ? (do certificates exist and where?)  

b) what such heat treatment is actually called up on the metals and complex joints in question?  

c) what investigation has been undertaken with Rockwell Hardness tests over the whole of the failed frames and in particular close to the failure?  

This is all shutting the gate after the horse has bolted but in the total shape of things we need to know along with the question will new ones be produced with up rated tubes and will they have an appropriately designed heat treatment with a certificate?  

NB I do have evidence that my nose leg has been “normalised”.  

Regards  

Bob Harrison. G-PTAG  

Robt.C.Harrison  

-----Original Message-----

 From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of Tom Friedland

 Sent: 20 January 2007 04:52

 To: europa-list(at)matronics.com

 Subject: Re: Mod 72 question  

Hi Graham  

I doubt that you will get an answer what caused the break.  It looks to be that it was most likely a tension break with perhaps some fatigue factor.  The upper tubes will have tension in the upper parts and that will be increased by the thrust.  There also could be some problem with non annealed brittleness from the closeness of the weld.   

The lower tubes should be ok as they have tension stress from weight bearing but that is cancelled by compression.  

But then what do I know.  My engineering studies were 50 years ago!  Now I am just a dumb doc.  

Tom

On 1/19/07, Graham Singleton <grahamsingleton(at)btinternet.com (grahamsingleton(at)btinternet.com)> wrote:   

--> Europa-List message posted by: Graham Singleton < grahamsingleton(at)btinternet.com (grahamsingleton(at)btinternet.com)>

 Roger

 what type of failure was it, bending, shear or fatigue?

 Graham

 Roger Bull wrote:

 >O.K. Bob, you woke me up!

 >

 >

 >Rob Housman's answer is on the ball.  Using Redux would necessitate   [quote]            - The Europa-List Email Forum -   --> http://www.matronics.com/Navigator?Europa-List              - NEW MATRONICS WEB FORUMS -   --> http://forums.matronics.com [b]

grahamsingleton(at)btinte
Guest

Posted: Sat Jan 20, 2007 4:01 am Post subject: Mod 72 question

Hi Tom

Most likely is excessive vibration, like when you lose a prop blade or 

heavy landing/prop strike

Be nice to know though. 

Graham



Tom Friedland wrote:



 	  Quote: 	
		   Hi Graham

  

 I doubt that you will get an answer what caused the break.  It looks 

 to be that it was most likely a tension break with perhaps some 

 fatigue factor.  The upper tubes will have tension in the upper parts 

 and that will be increased by the thrust.  There also could be some 

 problem with non annealed brittleness from the closeness of the weld.

  

 The lower tubes should be ok as they have tension stress from weight 

 bearing but that is cancelled by compression.

  

 But then what do I know.  My engineering studies were 50 years ago!  

 Now I am just a dumb doc.

  

 Tom

mikenjulie.parkin(at)btop
Guest

Posted: Sat Jan 20, 2007 1:41 pm Post subject: Mod 72 question

Bob, 

  

 This is why we are able to operate our aircraft so  cheaply.  If you want certificates and batch numbers,  buy a certified  aircraft and pay for your annual and C of A.  Also you would not be allowed  to perform your own maintenance.  If you are not happy with the  certified/experimental world, then do not ruin it for those of us that  are.

  

 regards,

  

 Mike

 [quote]   ---

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

Posted: Sat Jan 20, 2007 2:35 pm Post subject: Mod 72 question

Mike   

No intention of ruining it for anyone but just need to know to live. The thread wasn’t started by me anyway see below.  

If the information is there then let’s have some acknowledgement that the items have been properly normalised the PFA is a branch of the CAA anyway. As I said I know my nose leg was normalised, but can’t see why it touches any raw nerve to ask about the rest, they may well be, but let someone confirm it? I found a flaw in the material of my Jabiru engine mount and the pro. who fabricated it couldn’t believe he missed it. So why shouldn’t it be asked if this work has been done and more to the point lets hear of the check of the status of those that cracked. There’s no such cracks on mine with a heavy engine and an exceptionally heavy prop(but very correctly balanced) but then I did have the foresight to redux some close fitting thick walled tube in place 7 years ago, before any load cycles were applied. It is also conceivable that the “gods in the PFA” won’t accept my application for exemption.  

   

After all some people just may prefer (having floated their engine forward) to replace the whole landing frame having had some reassurances that the new issue ones have been up rated and normalised instead of doing mod 72.  

   

If there is a shortfall of strength in existing frames so needing mod 72 then IMHO it is just conceivable that cyclic fatigue is already present unless the frame was supported from scratch and prior to application of any load whatever.  

As you see I have not posted this rant on the full forum.  

Regards  

Bob H   

-----Original Message-----

 From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of Mike Parkin

 Sent: 20 January  2007 21:41

 To: europa-list(at)matronics.com

 Subject: Re: Mod 72 question  

     

Bob,   

    

   

    

This is why we are able to operate our aircraft so cheaply.  If you want certificates and batch numbers,  buy a certified aircraft and pay for your annual and C of A.  Also you would not be allowed to perform your own maintenance.  If you are not happy with the certified/experimental world, then do not ruin it for those of us that are.  

    

   

    

regards,  

    

   

    

Mike  

  [quote]    

---

mau11(at)free.fr
Guest

Posted: Sun Jan 21, 2007 11:15 am Post subject: Mod 72 question

hello Roger,

First of all happy new year!



We have made a check of our airplane to day with Alain Chabert and no

discover a failure on the engine support.

We read the mod 72 document and the mandatory classification is made by the

PFA only not by Europa company.



Question 1: On how many aircraft do you detect this type of failure?



Question 2: Do you have precise pilot report on the exact landing situation,

and on how many landings?

In example, some pilots have habitude to made hard landing and for us it is

normal situation.



Roger, thanks for your assistance



Michel AUVRAY Builder N°145

-----Message d'origine-----

De : owner-europa-list-server(at)matronics.com

[mailto:owner-europa-list-server(at)matronics.com]De la part de Roger Bull

Envoyé : vendredi 19 janvier 2007 21:42

À : europa-list(at)matronics.com

Objet : RE: Mod 72 question

O.K. Bob, you woke me up!

Rob Housman's answer is on the ball.  Using Redux would necessitate

increasing the clearance between the original tube and the new inserts.  The

Redux would not be strong enough to withstand the bending load, which is the

critical part of the overall stress.  The insert is intended to be a close

but not interference fit in the outer tubes after reaming.  Any small

clearance which may exist after fitting the new tubes will be taken up by

deflection caused by the initial load applied by the weight of the engine

and propeller.



The bending load is applied both by the vertical load from the weight of the

engine acting some 2.5" approx forward of the weld affected area, and also

by the small tube which is about 1" above the main horizontal tube. The

forward thrust from the propeller creates this bending load.  To that has to

be added on one side the torque reaction. (Distances are from memory as I am

writing this fom home).



I have made a small change to the Mod leaflet to make the applicability

criteria a little clearer.  The factors which affect applicability are

engine and propeller weights and c's of g forward of the undercarriage

mounting frame, and the engine torque.



Briefly all Rotax engined Europas, except those with classic engine

installations and light propellers as defined in the Mod leaflet, will need

to incorporate the Mod.  So all Rotax engined XS models, regardless of

whether 912, 912S or 914, and regardless of propeller will need the Mod.

Europas with engines other than Rotax will need to be checked on a case by

case basis.  We have already established that Europas with the Jabiru 3300

engine will need the Mod.



It was orginally intended that the news of the Mod would be promulgated by

the PFA and EA4 on their respective websites simultaneously - unfortunately

that did not happen.  The PFA have now updated their Type Acceptance Data

Sheet to include Mod 72.



We realise that quite a long time has elapsed since the failure took place

that gave rise to this Mod. It was necessary first to establish that the

failure was not a one-off due to a unique set of circumstances; research

into the original calculations established that there was a more general

problem.  The we had to devise a satisfactory solution that would be

reasonably straightforward to incorporate, then carry out tests to prove the

fix.  Then the method had to be agreed with the PFA, and the Mod leaflet

written.  This latter exercise proved rather drawn out, and several drafts

were needed before the current version was agreed.  Establishing why the

original error in stressing was made during the reign of EMIL proved almost

impossible, as the engineer concerned died a few years ago.



I realise that many people may feel that an unnecessary fuss is being made

about this Mod, but a look at the attached photo of the first, but not only,

failure should prove interesting.



Best regards,



Roger Bull

EA4



--

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