Last word of mine on reaming and rigging:
Thanks to my friend Pete Jeffers, and others asking me to clear up and answ
er a couple more things on rigging issues and errors and of course to addre
ss the use of a starboard pip pin point I failed to comment on and the obli
gatory legal protection comments on rigging:
In the manual, the rigging of the wings to the fuselage is about as clear a
s some of my quips. There are many nicknames for spar cups (buckets), lift
sockets or wing sockets, and spar bushings ( or cockpit sockets as I somet
imes call them), don=92t be confused. Read the manual carefully and note t
hat the fit of the wings to each other and then to the cockpit module is so
mewhat difficult to get right. In the old Classic, we rigged the wings and
cockpit module together on the floor in a vertical position to get the win
gs and fuselage bushings all in a line. I used zero tolerance bolts to do
my wing bush alignment and assure the bushes in the wing and fuselage were
perfectly aligned. Then I put the module in the lower =93canoe=94 (but not
using crates and beer cases) and of course it flexed and I had a devil of
a time figuring out what I did wrong and why my zero tolerance bolts would
no longer fit all three bushes as they did on the floor. I also noted the
port wing was against the fuselage side rather than an even fuselage to win
g gap. I didn=92t screw up, fiberglass moves, the cockpit module is not alw
ays straight, in any direction, and I learned that some minor fiberglass cl
earance issues in the wing spar hole, wing root length and slip fit toleran
ces were necessary for a plane that could be rigged easily on a daily basis
(I was so na=EFve. ) . In the XS kit, we rig with the cockpit module glue
d in the fuselage and still have alignment woes (surprise). For those of y
ou doing outdoor rigging, due to shop or hangar limitations, it is difficul
t to get this procedure precise. Doing both wings at once during failing d
aylight on a sloped drive way or a soggy yard complicates the rig further.
(I don=92t even use the dummy spar so don=92t ask.) Either way, the wings
should rig out of the fuselage easily and a reamer is nothing more than a
cleaning tool for swarf or to get a proper slip fit. Proper jigs and holdi
ng fixtures were essential for me to get things straight in my shop. In my
experience, and most of yours, the short wing spar bushings are glued and
aligned well. However, when fixing the cockpit module SO1 spar bushings, s
ome epoxy may weep in the hole, there may be contact errors between the fus
elage and wings that must be adjusted to properly align these cockpit SO1 s
par bushings. Initially the epoxy is what must be cleaned. I have gotten
stock from Europa of the =BD inch pip pins that measured exactly .5 inches.
No amount of grease can fix a .5 pin into a .5 bush pin to socket fit. M
inor factory building errors and tight tolerances required reaming of the s
par bush port side just to put the wings together initially using the =BD i
nch pin rather than the sloppy bolt used in rigging outside the aircraft.
In my work experience, the bolts fit easier because they are slightly under
sized rather than the pip pin as I stated before. In this case, reaming wa
s necessary to get the pin to fit the three bushings aligned with these bol
ts to allow more of a slip fit or I would break the pip pin head off eventu
ally. As Pete said so well: =93Difficulty in subsequent assembly has alwa
ys been shown to be caused by misalignment somewhere. Reamers can possibly
be used to remove paint/resin etc. but not to make things fit in the wrong
position.=94
As I said, if your wing to fuselage spar pin alignment bushes are out of al
ignment, use a drift to ascertain where the error is and fix that. If a sq
uare end of a 3/32 or =BC inch drift or punch hits an edge, and will not pa
ss, you have a bush that is out of alignment. Find out why. If a drift do
es not hang up around the hole but one can still feel the various bush join
ts, a taper pin should align those bushes. That is why I use a taper pin f
or the alignment and rigging process. Once the starboard taper pin rigging
aid is in, the port pair of bushes need to be checked and if there is a si
gnificant alignment problem that prevents a drift from passing at any one p
oint without hitting an edge, you have a problem. Fix it. If they are ali
gned, then the other pin =93should=94 fit without undo pounding, vice grips
and effort. Should I have only interference, I do ream the hole if it is
only an interference problem. This provides a smooth round triple bushing
hole for the pin to fit snugly in without the pin being grooved by the slig
htly skewed bushes. Remember, the reamer is to clearance a hole, not to fi
x a construction error. The final test is if both wings are supported to r
elieve pressure on the spar cups, each pin should be stiff, but rotate by h
and. With all the pins in, you know you went too far if you grab the wingt
ip and shake for and aft, up and down and the wings rattle badly, then you
need to put in new bushes. If done properly, the final rig at the field, e
ven after being disassembled for quite some time due to maintenance, will r
ig with little effort and be secure and slop free. If your wings are reall
y tight now, it will loosen with age and pin and bush wear, but with age ou
r strength fails also. I find it a tie, so I ream to allow the pins to rot
ate and slide firmly but without the need for hammers and pliers. I use no
more than a bit of grease to prevent corrosion and aid in the slip fit.
To appease my lawyers:
The Europa does not use two =BD inch pips because only the port side pip pi
n is necessary structurally. Normally the starboard pin is shortened to ju
st clear of the spar as it can interfere with the aileron quick disconnect.
The starboard wing lift sockets on the side of the fuselage keep the star
board root side spar from moving aft or allowing the port wing spar tip to
force the starboard spar to move anywhere. Therefore a starboard pip pin w
ould do nothing for you structurally except create an interference problem.
The port pip pin retains the starboard spar from deflecting aft under loa
d. Hence we install the pip pin to the port side, then washer it up to all
ow the pip pin retaining balls to just lock the spar cup, with hardened was
her, and the spar tip securely in place. Under bending loads the port pip
pin prevents the spar from creeping aft and interfering with the aileron qu
ick disconnects and linkage. Please follow the instructions and don=92t le
ave the taper pin you made for a rigging aid, installed for flight operatio
ns, this taper pin is a rigging aid only to align the port wing and seat th
e lift sockets and squeeze the wing gap seals if they expanded. Rig the st
arboard wing by pulling the starboard taper pin out to clear the cup. Inse
rt the starboard wing, and have the starboard wing supported by a stand or
your burley assistant, then insert the taper pin fully in the starboard sid
e to seat the starboard wing. Insert your port pip pin at this time. In t
he event things are still too tight to seat the port pip pin, consider usin
g two taper pins. If you did your job right, a slight tap of the port pip p
in with your palm will drive your port pin easily without bruising your han
d. Washer up your pip pin as required to allow the balls to lock out and h
old on the hardened washer on the spar cup firmly to prevent the starboard
spar from creeping aft to interfere with the aileron belcrank. Only allow
a fraction of an inch movement of the pin in and out after rig.
The lift sockets on the side of the fuselage should not be reamed for the l
ift pins. Keep these nice and tight, but quality control of the finish on
these pins and lift sockets may have been poor and there may be ridges on t
he stainless pin. Buffing the pins on a buffing wheel is perfectly fine, d
on=92t grind on them. Sharp edges on the wing lift socket face in the mach
ining process can mar the lift pins when rigging, and a slight chamfer of
these can prevent pin marring and aid rigging.
Ok, =91nuf said on that. Lawyers are satisfied.
My thanks to Pete, Fred and others who had further questions we discussed o
ff line with further hints to aid those of you building or those who have n
ever built and are trying to understand why things are like they are.
Best Regards,
Bud Yerly
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s 10
________________________________
From: owner-europa-list-server@matronics.com <owner-europa-list-server@matr
onics.com> on behalf of Bud Yerly <budyerly@msn.com>
Sent: Saturday, August 10, 2019 10:21:37 PM
Subject: RE: Europa-List: Reaming of spar and CM bushes
On first glance one would see it that way.
The lift pins on the aircraft side (like most gliders) take all the lifting
load so the wing spars don=92t really bend much and the wing spar pins are
in fact set properly to do their one and only job, absorb the bending shea
r load of the two spars. The force of the non bending spars put little for
ce on the cockpit module (in theory). I suppose one could take out the coc
kpit sockets and in a perfect positive load the spar pins would have no eff
ect on the cockpit module. However, as you intuitively figured out, the sp
ars have to be attached to the cockpit/fuselage to keep the wings from shif
ting laterally, as well as aft bending and forward bending and of course ho
w the heck could we rig the wings without the cockpit module pins and socke
ts...
We killed this horse some years ago and somehow all of us engineering types
figured out John Bewley got it right when doing the original structural an
alysis when the prototype was built. His testament is there are no ADs on
his structural work. His rework of the glider wing spar (Mod78) makes that
wing a brute. No need for a spar strap for sure.
Best Regards,
Bud Yerly
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________________________________
From: owner-europa-list-server@matronics.com <owner-europa-list-server@matr
onics.com> on behalf of Pete <peterz@zutrasoft.com>
Sent: Saturday, August 10, 2019 5:47:37 PM
Subject: Re: Europa-List: Reaming of spar and CM bushes
What i have never understood, is why the cockpit module spar pin bushings a
re not vertical slots, because when the wings are flexing under G, the lift
pins take the fuse lift loads, and the spar flexing (under positive G) ac
tually force the spar pins _downard_ against the cockpit module....obvious
ly totally counter-productive.
Pete
A239
On Aug 10, 2019, at 5:29 PM, Bud Yerly <budyerly@msn.com<mailto:budyerly@ms
n.com>> wrote:
Fred,
Back before my time when mod 52 was done for the GW increase. The classic
had two 3/8 pins originally. Mod 52 uses the =BD inch pins and a spar stra
p .
As the wings pull forward under load, the fuselage would flex so they put i
n the cross bar and the new sockets.
Then the concern was that the starboard wing spar could become dislodged fr
om the socket and interfere with controls. The quick fix was to hold in th
e spar tip with a pip pin. The port wing was figured would stay put, and t
he spar strap would prevent flexing of the spar.
That is all I know. Andy would have the particulars on the detailed histor
y. It sort of all makes sense.
Best Regards,
Bud Yerly
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________________________________
From: owner-europa-list-server@matronics.com<mailto:owner-europa-list-serve
r@matronics.com> <owner-europa-list-server@matronics.com<mailto:owner-europ
a-list-server@matronics.com>> on behalf of Fred Klein <freddythek10@gmail.c
om<mailto:freddythek10@gmail.com>>
Sent: Thursday, August 8, 2019 1:29:43 AM
>>
Subject: Re: Europa-List: Reaming of spar and CM bushes
Bud=85you mention the use of the SouthCo pip pin on the port side and the A
llen bolt pin on starboard.
Do you know the reason for using different types of pins here?
Is there any downside to using SouthCo pip pins both port and starboard?=85
seems I=92ve heard that some builders have done so.
Fred
On Aug 7, 2019, at 8:35 PM, Bud Yerly <budyerly@msn.com<mailto:budyerly@msn
.com>> wrote:
The SouthCo pip pin is nominally .4985 inches.
The Allen bolt pin for the starboard side is .497 to .495.
|