Grob Astir AD spar spigots

On Apr 20, 7:44 am, wrote:

I saw a reference to a repair team in one of Bob Kuykendall's posts, a
team that did the 103's, but I suppose those were Grob guys Bob?

Gosh, it's been like a dozen years, I don't remember that much about
it. But as I recall it, it _was_ a team sent around by Grob, they'd
lined up several aircraft each at several shops around the country and
did a grand tour. I saw them briefly, I think at Steve Brown's Bay
Area Composite Repair.

As I recall the repair involved cutting through the spar stub shear
web to liberate the chunks of plywood to which the spigot was bolted
or riveted, leaving an ugly rectangular notch at the end of the stub
but not removing material from the spar caps. The beefier replacement
spigot and its support (probably plywood, but perhaps prefabbed
fiberglass plate, I don't recall) was placed into this notch, aligned
with a fixture that the team had brought with them, and floxed into
position. After the flox cured, the spigot and its support was secured
with several shear wraps of cloth. I don't recall if they ground away
the original shear wraps; they might have done so to keep the spar
stub within its original envelope.

As an aside, this series of repairs is one of the events where I first
started to comprehend that there's no particular magic to composite
aircraft structure. I remember spending quite a while looking at one
of the cut-open aircraft under repair after the guys had knocked off
for the day. I don't remember much of what I saw, but I do remember
thinking "What, is this all there is?" Of course, there's a lot of
careful engineering to it, engineering that I'm not qualified to
practice or for some of it to even understand. But I think that a lot
of it is just a mix of common sense plus stuff that people tried and
tested and found to work sufficiently, and the engineering came later
to figure out _why_ it worked.

Thanks, Bob K.

Hello Stephen,

FYI - An AD for this issue was put out in Canada many years ago
(February 1991)!

looking at grob.aerospace.de I found this document:

http://www.grob-aerospace.net/filead...SB_Summary.pdf

And searching this document I found:

11.10.90
Überprüfung und Austausch der Holmstummelbolzen
Inspection and replacement of spar spigot assemblies
ASTIR CS, ASTIR CS 77, ASTIR JEANS, STANDARD II, CLUB II, CLUB III,
STANDARD III, CLUB IIIb
alle Werk-Nr. / all S/N

regards
Werner

Todd,
The work must be done in a FAA certifid glider repair station, like
John Murry's or Gehrlein in your neck of the woods. it involves about
20 hours of work + the cost of the kit from Grob. It involves
assembling the ship with wax donuts on the old spigots to determine
the excess lateral slop that must be removed when the new spigots are
installed, then grind and remove the old, then fit the new with
factory jig, scarf spar but and lay up 8 layers of 92125 for the
replacement spar wrap. I would estimat $1800 to $2400 bucks.
JJ

JJ,
Would Rutan style 7725 be a similar cloth to the 92125 European cloth?
Thanks,
Brad


On Apr 20, 5:20 pm, JJ Sinclair wrote:
Todd,
The work must be done in a FAA certifid glider repair station, like
John Murry's or Gehrlein in your neck of the woods. it involves about
20 hours of work + the cost of the kit from Grob. It involves
assembling the ship with wax donuts on the old spigots to determine
the excess lateral slop that must be removed when the new spigots are
installed, then grind and remove the old, then fit the new with
factory jig, scarf spar but and lay up 8 layers of 92125 for the
replacement spar wrap. I would estimat $1800 to $2400 bucks.
JJ

On Apr 22, 10:25 am, Brad wrote:
JJ,
Would Rutan style 7725 be a similar cloth to the 92125 European cloth?
Thanks,
Brad
Yep, but when working with certified aircraft like the 102, one must
use the specified stuff. The kit I got from Grob had per-cut 92125
sections, everything but resin...............BTW, Williams Soaring
(Rex) just got 50 gallons of L285 epoxy at half the price that Spruce
& Seciality is getting.
JJ

JJ,

Thanks a lot for this information.

It was a factory supplied jig that was used for the replacement ?

Todd


On Apr 20, 8:20 pm, JJ Sinclair wrote:
Todd,
The work must be done in a FAA certifid glider repair station, like
John Murry's or Gehrlein in your neck of the woods. it involves about
20 hours of work + the cost of the kit from Grob. It involves
assembling the ship with wax donuts on the old spigots to determine
the excess lateral slop that must be removed when the new spigots are
installed, then grind and remove the old, then fit the new with
factory jig, scarf spar but and lay up 8 layers of 92125 for the
replacement spar wrap. I would estimat $1800 to $2400 bucks.
JJ

On Apr 23, 8:46 am, toad wrote:
JJ,

Thanks a lot for this information.

It was a factory supplied jig that was used for the replacement ?

Todd

On Apr 20, 8:20 pm, JJ Sinclair wrote:

Todd,
The work must be done in a FAA certifid glider repair station, like
John Murry's or Gehrlein in your neck of the woods. it involves about
20 hours of work + the cost of the kit from Grob. It involves
assembling the ship with wax donuts on the old spigots to determine
the excess lateral slop that must be removed when the new spigots are
installed, then grind and remove the old, then fit the new with
factory jig, scarf spar but and lay up 8 layers of 92125 for the
replacement spar wrap. I would estimat $1800 to $2400 bucks.
JJ

Todd, Did you happen to notice the 3/21/05 response date on the
Airworthiness Concern Statement?

Todd, Did you happen to notice the 3/21/05 response date on the
Airworthiness Concern Statement?

Yes, at least after it was pointed out :-) I think that there might
be a typo. The real deadline for comments in May 11th, I think.

Todd

On Apr 23, 10:11 am, toad wrote:
Todd, Did you happen to notice the 3/21/05 response date on the
Airworthiness Concern Statement?

Yes, at least after it was pointed out :-) I think that there might
be a typo. The real deadline for comments in May 11th, I think.

Todd


Correct, 5/11/2007 is the deadline for comments into the AOPA.

Jim

What the heck is a spar spigot?