>>
>> I would be interested to know the insertion forces of the main spar pins
>in
>> the current flying Europas. On mine it is essential that the wings are
>> supported and wiggled at the tips before the pins can be inserted. This
>> means that rigging cannot be done single handed without 13 ft long arms
>or
>> fiddling around with supports.
>>
>> Ideally the weight of the wings should be taken by the structure (cups,
>entry
>> frame) such that the holes are in line before the pins are inserted, but I
>> have so far been unable to achieve this happy state despite
>experimentation
>> with packing pieces. Incidentally the pins drop in easily if the wings
>are
>> pinned to a jig accurately matching the cockpit module holes, so there
>are
>> no dimensional errors. How about it Jim N ?
>>
>> Graham C - G-EMIN
>
>IMHO the cups are there only to assist rigging and are not supposed to give
>any structural support. I always thought that it was the spar pins that
>were supposed to transfer the 'load' to the fuselage,
>If this is the case, then the wings will always need 'jiggling about' as I
>don't think that the weight of the wings should be taken on the lift pins
>alone either, although once the wings are slotted into the lift pins, then
>a quick-let-go-and-spar-pin-insertion is OK - and necessary for rigging.
>
Quite right, the cups are there simply as an aid but if they are not a nice
snug fit they will not hold the spars in the correct place for the pins to be
inserted. Assuming you are not having a problem
with the lift pins and flaps, and the spars are going in all the way, then
the only miss alignment should be in the vertical plane which can be adjusted
by the tuffnol slippers (assuming you have fitted these), you mentioned packing
pieces so I think you are in the right area, but perhaps haven't quite got it
right yet. Setting the height of the spars accurately, with the slippers is
essential for easy rigging. I found the best way to set the height was to rig
the aircraft, measure the gap between the bottom of the spare and the opening,
make up the slipper to be just a bit on the thin side and fix it in position
bedded on a stiff flox/Redux mix, and leave to cure, making sure the slipper
is in contact with the spare. This operation is of course only possible before
the wing root fairings are fitted, so you may have a little problem there!
You could consider cutting away sufficient fairing to fit the slippers and then
replacing it.
Also I found grinding a cone shape on the end of the spar pins and keep
them well
greased helps to assist alignment and reduce wear.
The only time we have a problem rigging is if the ground is very uneven and the
rigging aid or outrigger is pushing the wing tip up to high. If the wing
is allowed
to hang on the lift pins and spar cups the pins will go in with a minimum
amount of
effort, and never need any tip wiggling. In fact even when there are two of us
rigging we take a wing each rather than feel the need to help each other.
By the way, the spar pins transfer very little if any of the load to the wings,
there main purpose is to join the wings together. The lift pins are designed to
take the total load of the aircraft so hanging the weight of a wing on them
will not be a problem.
Jim Naylor No 39
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