Grob G102 Setup

Assuming your Grob 102 rigs the same as the Astir CS I used to fly
(maybe it's the same model), I always rigged best with just two people.
Really very simple:

Before starting - Grease all pins, including pins on spar ends, and
*check collars are unlocked* - it's amazing how often one has been
locked accidentally, and if so you'll never rig it.

1. Slide in starboard wing, lock the collars and trestle tip.

2. Check that the end of the spar is centred vertically in the space
wher the port wing spar will go. If not, adjust by rotating fuselage
(usually best, as the leverage of raising and lowering the tip often
rotates the fueslage so the spar end is still not centred). If the
fuselage slips in the belly dolly, a third person could hold the tail in
the correct position.

3. Insert port wing until the pins on the fuselage just start to engage
(you might need to reach over and lift the trailing edge slightly), then
trestle tip to take the weight, but keep wingtip holder at tip.
Trestling is not essential here, but why lose a friend?

4. Look at starboard wing root to see where the pin on the port wing
root has to engage with a bush/olive (i.e. hole). Ask wing tip holder to
raise/lower (trestle shouldn't have been too high to permit this)/move
forward/move back until this is lined up. *If the pin/hole are not
aligned the wing will never go on*. *Do not allow some well-meaning
idiot who has never rigged a glider of this type to wiggle the wingtip*.

5. Check the fuselage/port wing root pins are still engaged - if so,
reach over the wing, lift the trailing edge a little, lift the leading
edge a little and slide it in to place. Lock off collars.

If this takes more than 5 minutes you are doing it wrong. The two key
points are (a) making sure the starboard wing spar end is central
vertically and (b) aligning the port spar end pin with the hole in the
starboard wing.




wrote:
As stated by HL, item one is an absolute! At Grob in Bluffton they have a
fuselage dolly that holds
it firmly in place to keep the fuselage from rotating after the right wing
is in place.

I assemble mine (upon rare occasion anymore since I keep it assembled in a
hangar now) by myself
with a wing holder but the most important little item turned out to be a
jack under the right wing with
very thick padding on top, under the wing about 1-2 feet from the fuselage
placed under the spar.
This keeps the fuselage from rotating when the weight of the left wing root
starts to load the fuselage
on its way in. A wing support at the tip doesn't really do the job because
of the wing flex and lets the
fuselage move sideways slightly.

Gale Winnett
Grob 102 III

"Chris Reed" wrote in message
...

If this takes more than 5 minutes you are doing it wrong. The two key
points are (a) making sure the starboard wing spar end is central
vertically and (b) aligning the port spar end pin with the hole in the
starboard wing.

Well, I'm definitely doing it wrong - I'd say we'd be lucky to get the wings
on in less than 30-45 minutes and without losing a good 2-3 lbs of body
weight due to perspiration!

One time before de-rigging and at the suggestion of another club member I
marked the proper spar location for the right wing on the bulkhead just
behind it. Now I know when I put the right wing in that it is in the proper
place, or at least very close.

We do check all the pins and their mating bushings before trying to get them
to mate. The frustrating thing is that they all look just fine but the wing
will still refuse to go in. I have tried (due to frustration) to wiggle the
wing fore and aft and up and down but that never helps at all.

Based on the experience with wiggling the vert stab and many of the comments
here it sounds like my main problem is some twist in the fuselage during the
assembly process. I will pay closer attention to this next time and see if
things go more smoothly.

BDS

If everythig is alined and it won't go in, the front and rear drag pins need
more grease! The swivelling pins with the groove on them have a very short
and steep taper, and the spring fingers inside the receptacle on the fuse
are strong. A good viscous grease like wheel bearing grease works better
than white lithium. My new favorite (Thanks Larry "01") is Radio Shack
lubricating gel. I have not tried STP or Motor Honey but they might work
even better. They are liquid and harder to handle though. The part about
centering the right spar in the left spar box opening is critical.

Perfect practice makes perfect performance--
Best of luck

HL Falbaum
--

"BDS" wrote in message
...
"Chris Reed" wrote in message
...

We do check all the pins and their mating bushings before trying to get
them
to mate. The frustrating thing is that they all look just fine but the
wing
will still refuse to go in. I have tried (due to frustration) to wiggle
the
wing fore and aft and up and down but that never helps at all

BDS

Cleaning and greasing help a lot, or did with our G-103. Once we got
our trailer more user friendly, a few people started landing out.
Interesting how easy it got to rig and derig once cleaned up and lubed.

Frank Whiteley

Well, I own a 102 Std III and have never had any real trouble with it,
but I think that the the most critical points are 1) having the right
spar position marked on the bulkhead and 2) having a 1-man rig. The
1-man rig allows the weight of the wing to be supported at the center
of the wing, so that there is no vertical load being supported at the
inboard end. Those loads are being supported by the pin fittings that
you are trying to get to slide togethor. They will slide better if
they are not under load.

Todd Smith
Grob 102
3S

"BDS" wrote:

The frustrating thing is that they all look just fine but the wing
will still refuse to go in. I have tried (due to frustration) to wiggle
wing fore and aft and up and down but that never helps at all

Install the right wing, use a support a little inboard of the middle of the
right wing (near the wings CG). When you install the left wing stand at the
leading edge, and have a helper at the trailing edge. Support the wings
weight while you slide it in (use your right hand ). If everything is
aligned but it still doesn´t move, tilt the fuselage on its dolly very
slightly (like a rocking motion) with your left hand to make it go together.
A VERY slight, hardly noticeable back and forth motion on the left wingtip
can help, too.

Once you and your helpers have some training, it isn´t harder to assemble
than any other glider.

Michael

That's essentially how one of our club members does it on his CS,
except he does it alone using his tip stand, wing dolly, ramp and
jacks, wing stands and alignment marks (most of the rig he built
himself as copies from an LS-3 setup at the club). He does leave his
trailer in the same place week to week, but he rigs/derigs daily. It
takes a bit of aligning if he moves the trailer, but not a real hassle.

Frank Whiteley