Download - Vintage Glider Club

SNIPPETS
searched in my technical library, I found
it in my book “Bau von Gleit und
Segelflugzeugen” by Hans Jacobs. (Construction
of Gliders and Sailplanes). This
book was printed in 1940. There it states
that the glue was developed by Professor
Klemm, so you are right in your presumption.
The Kaurite glue was mixed
with “KUNSTHARZ” (artificial resin) to
give it elastic qualitiy”. Direct translation
by CW. This is the known Kaurite
glue. Klemmleim has been developed by
Dr.Klemm. This consists of normal
Kaurite with a meagre additive. This very
much improves the elastic quality of the
glue. This consists of the additive hardened
artificial resin in powder form. It is
called “Klemm Powder”. The preparation
is exactly the same as that for normal
Kaurite glue and the same RED cold
hardener is used to set it”. CW thanks
Ingvar very much for this information.
CW
CW also writes that some Kaurite glued
skinned wings are still amazingly accurate
(as are Casein glued wings), on
Swedish and German war time built
sailplanes. Whereas Aerolite glued
Slingsby and Elliot wing skinned
sailplanes sometimes reveal a “starved
horse” effect. However, one can not complain
about the accurate wing plywood
surfaces of T.21b s etc. and the accuracy
of CERTUS glued wing surfaces of old
French sailplanes. CW asks whether
CERTUS is an ancestor of AERODUX
glue? That some Slingsby and Elliott
plywood wing surfaces are good and others
are not, makes CW wonder whether
these firms also discovered an additive to
make AEROLITE 300 glues more flexible?
Frits Ruth writes that powdered bakelite
was added to Kaurite glue in order to
make it more flexible when set, so that
there should be less distortion of plywood
(better accuracy of profile) on
wings etc.
Progress
in restoring the V-20
by Neelco Osinga
New glue
Last week I visited the workshop of the
Twentse Zweefvliegclub. Also Jan
Forster was invited. He demonstrated a
new way of covering the wings and fuselage,
the Kautschuk glue method.
Kautschuk glue is made by IRSA.
Caoutchouc is the French word for non
vulcanised rubber. The glue seems to be
like the famous white cold glue for
Above: hard at work on the V-20
wood, e.g. Ceta Bever in the Netherlands.
After drying, the glue becomes
transparent and feels like rubber. It is a
non poison stuff and nearly without
smell.
Jan Forster as a teacher
Jan Forster is not only a good technician
and member of our VGC committee but
also a good teacher.
He demonstrated the way to bring the
glue like paint onto the torsion box of
the wings and onto the ribs. The glue
should not be dry when the fabric, in this
case a new type of synthetic fabric of
Diatex, is laid on the wing. On the torsion
box, only a narrow track of glue has
to be applied. To prevent drying, the glue
is painted in sections of about maximum
50 centimetres. After laying down, the
glue has to be rubbed in the fabric. The
fabric must be laid under some slight
tension so that there are no folds. After
completely drying the, the fabric can be
brought on tension in the normal way;
flat-iron and with dope and afterwards,
eventually painted. Jan said that this
method of covering the glider results in
about half the weight of covering with
old fashioned cotton fabric. After one day
of hard work both wings had been covered.
The V-20 gets its final look
After covering the whole glider with the
new fabric, inclusive of the fuselage, the
glider will be painted in the original
colours. The canopy is nearly ready
according to the original photographs.
The owner, Tonny Wensing, is collecting
original pre-war instruments. I expect
that Hans Bekker, the responsible technician,
can finish the titanic works this
year. But I know that both Tonny and
Hans prefer safety and good quality,
rather than hurry.
The local television station in
Enschede is making a documentary of the
restoration works, a good promotion for
gliding.
Fantastic
book for
technicians
For the members
who want to learn
the new method
of covering the
glider with the
K a u t s c h u k
method I warmly
recommend
the new book
for technicians: "Houten
zweefvliegtuigen & techniek", by Jan
Forster, ISBN / EAN 978-90-9022122-
9, issued by the VGC and the Vereniging
Historische Zweefvliegtuigen (Dutch
VGC). Price: €20.=. It is in the Dutch
language. For those technicians who do
not speak Dutch: an Englishman told me
that he could understand about 90 % of
the written text. The book has an appendix:
a dictionary of Dutch, English and
German technical words.
I give an example of the quality of the
book. Nobody could tell me the mechanism
of shrinking of the fabric by doping,
so that it will be tight, even not the
well known technical books. The book
of Jan gives a good explanation!
VGC News No. 123 Spring 2008 27