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 N145
-----Message d'origine-----
De : owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com]De la part de Roger Bull
Envoy : vendredi 19 janvier 2007 21:42
: europa-list@matronics.com
Objet : RE: Europa-List: 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
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com]On Behalf Of Robert
Borger
Sent: 19 January 2007 1:48 pm
Subject: Europa-List: 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.
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