That midget with long arms would have been useful for work in the
tailcone.
Having had a bit of experience with cutting tools I know that a hand
reamer
has a 1 degree entrance taper to facilitate getting the cut started
(whereas
a chucking reamer has a 45 degree chamfer, but that is suitable only on
a
machine driven reamer, not one turned by hand). I had my reamer
fabricated
by a local toolmaker with about =BD inch of taper, enough to allow the
thing
to get started but not so much as to make it impossible to fit the pin
all
the way in. It turns out that the forward bolt through the landing gear
frame is not far enough aft to allow the first pin I have inserted to go
all
the way in, but it does not project enough to interfere with the engine
mount.
Also, the Europa supplied pins do have a 45 degree chamfer on one end,
not
that such a small chamfer helps much in overcoming the taper on the
reamer.
Your suggestion to avoid priming per the procedure is, in retrospect, a
very
good one. Inserting the pins with wet primer is probably the best
approach
since the primer will provide some lubricity while wet, and corrosion
prevention when cured.
Lacking a friendly neighborhood midget, I hammered under the assumption
that
engine vibration would contribute more fatigue cycles, although at lower
amplitude, than hammering.
I did comprehend your suggestion about modifying the pins, and I do have
a
full machine shop at my disposal, but decided that since I expected
(fool
that I am) a fit with clearance, modifying the pins was not necessary.
Best regards,
Rob Housman
Irvine, CA
Europa XS Tri-Gear
A070
Airframe complete
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Carl
Pattinson
Sent: Monday, September 29, 2008 9:29 AM
Subject: Europa-List: Re: Europa-List: Mod 72 - Undercarriage mounting
frame
strengthening
Rob,
Unfortunately the factory failed to mention that the reamer supplied (as
with most reamers) is tapered at the end, whereas the supplied inserts
are
not. The tapered portion of the reamer is about 1 inch long, the rest
being
the correct dimension.
This means that no matter how big a hammer you use, the F****ing things
will
never go all the way in.
The easy solution which will only work if you do it before jamming the
insert in the tube is to file down the end of the taper so that it fits
all
the way - you will need a lathe or drill to do this.
I didnt bother pre priming the inserts or tube, simply coated everything
with red lead primer before assembly and hammered the inserts into
place.
Once the primer sets there is no way anything will ever come apart.
If you have a situation where the inserts are jammed halfway into the
tube,
your only option is to saw off the protruding end (of the insert), as I
believe many builders have done. The inserts are of such a length that
they
go all the way up to the bolts which attach the frame to the fuselage.
As
long as there is no more than about an inch protruding from the end the
inserts will be doing their job and sawing off the excess should not
weaken
the finished job.
As a disclaimer I guess I should say clear this with your inspector or
the
Europa folks first (before reaching for the hacksaw)
Good luck,
Carl Pattinson
PS: Hopefully all that pounding hasnt damaged the fuselage surrounding
the
frame or the alloy plates bonded into the structure. Ideally there
should be
somebody holding a large lump of steel (EG: a big hammer - American or
otherwise !!!) at the other end of the tube (within the frame) that you
are
hammering on. This should speed up the insertion process and minimise
any
damage to the surrounding structures. You may need a midget with long
arms
to hold the hammer.
----- Original Message -----
From: Rob Housman <mailto:rob@hyperion-ef.com>
Sent: Monday, September 29, 2008 3:51 PM
Subject: Europa-List: Mod 72 - Undercarriage mounting frame
strengthening
Having been working mostly on those factory mandated or recommended
modifications of late, I now realize that it is much easier to build an
airplane than it is to repair one. Mod 70 (Mass balance arm) was merely
tedious, working deep in the tailcone, one handed, through small access
holes, but Mod 73 (Tailplane retention) and Mod 59 (Shimmy damper) did
not
go well when following the written procedures, and now with Mod 72 there
is
more of that wonderful English understatement: =93Insert the tubes -
they will
probably need a light tap to fit them=94 it says in the procedure.
English
hammers must be considerably larger and heavier than American hammers
(or
16.5 mm reamers must be a bit larger) because =93a light tap=94 does
nothing.
After pounding away for entirely too long, and peening the ends of the
tubes
where the hammer repeatedly struck, I finally fabricated a steel spud to
put
between the offending pin and the hammer. This made it easier to keep
pounding with less damage to the pins, or to the adjacent smaller
diameter
tubes to which the engine mounts attach if I were to miss the target.
The
steel spud is starting to look like a mushroom from all of those
=93light
taps.=94
I should have retained my initial skepticism regarding the fit of
painted
tubes, which after painting with etch primer are larger than 16.5mm, but
no,
I foolishly believed that the factory had actually tried this procedure.
Well folks, the paint makes the pin almost impossible to fit.
Fearing complaints from my neighbors about so much hammering on a
peaceful
Sunday afternoon I finally quit pounding with the intention of resuming
mid-day today when most of my neighbors will be away at work. As of
yesterday afternoon one pin was snug against the bolt attaching the
frame to
the fuselage and the other was still barely halfway home.
Now, if I could find one of those English hammers at Home Depot=85.
Best regards,
Rob Housman
Irvine, CA
Europa XS Tri-Gear
A070
Airframe complete
_____
No viruses found in this incoming message
Scanned by iolo AntiVirus 1.5.5.5
http://www.iolo.com <http://www.iolo.com/iav/iavpop3>
_____
No viruses found in this outgoing message
Scanned by iolo AntiVirus 1.5.5.5
http://www.iolo.com <http://www.iolo.com/iav/iavsmtp>
|