At 18:24 31 January 2016, Frank Whiteley wrote:
On Saturday, January 30, 2016 at 2:49:27 PM UTC-7, K m wrote:
On Thursday, January 28, 2016 at 8:56:01 PM UTC-7, K m
wrote:
Group,
My club is looking to convert a Twin Astir brake system to a
Hydraulic
=
Disk from a Mechanical Drum. Our serial number does not fall
within the
ser=
ial number range of the Kit that is offered by Lindner. We have the
Lindner=
kit and will be going with a 337. My question is does anyone
know of a
337=
on an Astir brake mod? Also, I have been trying to find info on
any
differ=
ent versions of the Astir and can't find much. Is there any
reference
onlin=
e that points to different models or versions? Ive read that water
ballast
=
was an option and some models came with a disk brake from the
factory
(Thes=
e have a different wheel carrier structure). Does anyone know if
gross
weig=
hts remained the same on the Astir through the production run?
This info
ma=
y hel when submitting paperwork to the FAA.
Thanks!
=20
It was brought to my attention in a PM that my first post may
have been
t=
oo vague for a legitimate answer. Utah Soaring Association (USA)is
retrofit=
ting a disk brake onto a G103 Twin Astir. It was also pointed out
to me
tha=
t there were 7 different variants of the Astir (?!). The USA club
owns two
=
Twin II's (One an Acro) and two Astir's. I know of some factory
options
for=
the Astir (Including a trainer version) but never anything close to
7
vari=
ants. Is there reference for this somewhere?
Our Astirs have the welded steel tube wheel carriers which
rotate
sideway=
s under the rear seat when they retract.=20
Thanks for any info.

Had a phone chat with the original poster this morning. USA owns
two Twin
A=
stir 1's with the retract. The serial numbers are 5 apart, 3285
and 3290.
=
The G-103 production underwent some serial production
changes. For
exampl=
e, some have a single retract handle in the front seat, others in
both
seat=
s. It's not clear what changes may have been options or serial
production
=
changes. ltb-Lindner.com hopefully has serial production data
and would
kn=
ow whether the G-103 in question was produced with a drum or
disc brake.
T=
he service bulletin allows retro-fitting of a disc brake on serial
numbers
=
3000-3139, except for the T models (fixed gear). Presumably,
higher
serial=
numbers weren't included because they were built with disc
brakes
installe=
d. At least one of the above has a disc brake. If that's the case,
then it
=
would seem the disc brake installation could be made as
restorative
without=
a 337. Maybe someone qualified could chime in about that. There
were
some=
further improvements made to the original disc brake system,
which would
b=
e an approved installation.

Frank Whiteley-

The Nutmeg Soaring Association of Freehold, NY has 3 Twin 1's,
and has sold another one, for a total of 4 which we have owned.
We retrofitted one with a disc brake IAW TM 315-50 last spring.
That one still has the old cast aluminum parts in the gear cage.
After a few months of operation with the new disc brake, a side load
managed to bend the disc plate, and render it inoperable. Our
mechanics deemed the part to be either substandard or under-
designed and filed a complaint with TOST through Wings and
Wheels. It took a few months, but TOST responded by replacing
the bent disc with a new stronger one, and also said they would
replace other older defective discs in the field. We have
corresponded with at least one other Twin 1 club operator in
Germany who told us that they previously had a disc brake, had
problems with it, and went back to the drum brake to avoid the
previously noted problems. So, it seems entirely possible that the
Utah late serial number Twin 1 was originally produced with a disc
brake, but later changed to the drum brake configuration due to an
under-designed disc brake plate. If you get a new disc brake from
TOST, it should now come standard with the thicker reinforced
plate. Ours has been fine since we installed the beefed up plate.

Mike Opitz