Jeroen,
I whacked this out this evening. It is a bit rough but gives a bit more de
tail.
You can mount the wings vertical like the book or horizontal. It is impera
tive that you make sure the wings are at the same angle so the spars are de
ad parallel in their vertical orientation. Take a look at the .pdf I'm att
aching. I hope it is a bit clearer. It also has a few other things to con
sider.
Best Regards,
Bud Yerly
-----Original Message-----
From: owner-europa-list-server@matronics.com <owner-europa-list-server@matr
onics.com> On Behalf Of jglazener
Sent: Monday, December 21, 2020 11:45 AM
Subject: Europa-List: Re: Spar Strap
Hello Bud, just make sure I understand everything correctly, you say the sp
ars should be vertical, rather than the wings vertical which the manual see
ms to suggest. That would certainly make setting the wings up on simple saw
horses a lot easier. Rgds, Jeroen
budyerly@msn.com wrote:
> Just my two cents.
> The spar strap prevents the spars from doing two things.
> Bending back and impacting the aileron cross connect, twisting or separat
ing.
>
> As many have found on the original Classic, the spar cups took abuse. So
me of that due to poor security of the starboard tip by the 3/8 inch pin.
Some from the twisting of the spars under load, and some due to poor techni
que on installation and rigging.
>
> With the GW increase testing, enlarging the pin to allow a pip pin to sec
urely hold the spars firmly from creeping aft was a very thoughtful idea.
The spar strap really keeps the spars from bending which they do under load
. Remember, the XS short wing spar has no bid around it for a shear web, s
o the roves are good in vertical bending but not so great in twisting or bo
wing.
>
> So belts and suspenders. Either enlarge the thickness of the spars with
shear webbing as in the glider wing, or retain them seems to be the dilemma
. They chose simple, a spar strap.
>
> I would always install a spar strap. It aids rigging if built right with
some clearance, reduces pressure on the spar cup during rigging, assists i
n keeping the spars safely put under high G pullouts.
>
> Take the time and do it right. If you don't do it in construction, it ma
y never get done. In testing, if a situation requires a quick pull out, th
e added spar strap fixation may become a factor. I try never to cut corner
s. Anything worth doing is worth doing right.
>
> Technique:
> Support the wings and spars so the spars are exactly vertical, each wing
is at the same incidence and the spar pins rotate easily. This is importan
t to ensure the strap is going to be properly aligned and not just slightly
askew. NEVER clamp the spars together to get alignment.
>
> Wrap the starboard spar with blue painters tape then the release tape to
give you a few thousands more room for rigging and more importantly deriggi
ng during construction.
>
> Make the upper curved inlet as shown but do the same on the lower on the
starboard side of the cup layup to ease rigging. I make my spar strap "ra
mp" about 1/4 inch larger than depicted as well as the strap to allow nice
clean trimming.
> Make your glass wrap as shown in the manual.
> Wrap peel ply around your glass to prevent sagging and use some release t
ape to hold the peel ply from sagging if necessary.
>
> In cold climates:
> Try to find a shop that may let you do the work in the warm, but if that
is impossible:
> Make a box over the spars out of styrofoam and use an incandescent light
to keep it warm to cure.
>
> Once cured, if heat treat is necessary pull apart the wings and heat trea
t slowly in the garage.
>
> The spar strap when done properly is an excellent aid in rigging as well.
As the starboard spar is inserted, it is aligned with the strap and will
slide along the port spar and assist in self alignment. The spars stay pro
perly vertical, assisting the wing tip assistant. If the builder also inst
alls a rigging aid for the spar to slide on and assist in alignment,(keepin
g the spar from sliding aft) and building a small ramp on the spar root to
assist lifting the spar as it hits the cup and thereby aligning the pins to
very near their required elevation, even the most clumsy of assistants eve
n without a saw horse or trestle under the wing will be amazed how easy the
rig is.
>
> Best Regards,
> Have a great holiday.. Bud Yerly
--------
Jeroen
http://www.europaowners.org/main.php?g2_itemId=44165
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=499758#499758
|