SZD-9 bis Bocian – the immortal glider [Vintage Sky]

SZD-9 bis Bocian – the immortal glider [Vintage Sky]


Hello and welcome to Vintage Sky.
Today I’m going to tell you about the glider which was designed for everything.
this is the SZD-9 Bocian. Its name means “Stork” – a very
beautiful bird, very common in Poland. It’s believed to bring good luck
if stork makes a nest on your house; and storks fly away from Poland to warm
countries for winter and therefore they they are the masters of navigation as
well as thermal soaring. Bocian was built in SZD works – Szybowcowy Zakład Doświadczalny, this means Experimental Glider Works and
this was a great company which built about 50 different types of gliders in
Poland. SZD-9 Bocian glider was designed as all-in-one glider on which
you could start with your initial basic training and go on to record flights,
high altitude flights and even aerobatics. It was designed in the beginning of
1950s this was the time when gliding schools finally resigned from the
single-seat method of training about which I told you in the episode about
Żaba glider and the two-seat glider was was required.
Also, there was a category in gliding sport for to seat the gliders which was
later withdrawn and therefore there was a need for a two-seat high-performance
modern glider. Bocian was designed by engineers team
led by Marian Wasilewski, Roman Zatwarnicki and Justyn Sandauer. They used some
modern design features which were not so common at those times especially I mean
the wing which was swept forward this allowed for a great visibility from the
back cockpit both to the sides and to front as the seat was higher than the front seat was higher, as well as it made the second pilot (in this case mostly the instructor)
sit in the center of gravity so the performance, the behavior of the
glider did not change much after student was flying first solo flights,
and this was a nice feature for a glider which was used for training. Bocian was
one of the first gliders in the world which used the design of forward swept
wing. Wings of Bocian were pretty high above the ground so it was
hard to hit the ground while learning takeoff or landing or even outlanding
in some uneven field. Test flights of Bocian were in the early 1950s.
Tests were pretty much positive. One great change which was made was the
angle of incidence which was modified so that the fuselage of the glider was more
parallel to the ground therefore creating less drag and this increased
the glide ratio of the prototype from 21 to 26. Also the wheel was moved to the
back because the glider was pretty heavy. Wheel which was behind the center of
gravity made it easier to transport it on the ground, it had special carry bars
on the on the tailplane so it was easier to lift the glider and transport
it on the ground. As it was a training glider bringing it back
from the place where it landed was pretty frequent. Adjustable
rudder pedals were introduced, here you can see them. There is red pin on the
side of each pedal – you pull it out then you adjust the pedal to your preference
and you block it so therefore you can make the glider more comfortable. Obviously this feature was available only on the ground. When it comes to test
flying the glider there was an interesting episode. While testing the
tailspin behavior of Bocian there were tests which included performing a
flat spin which is a pretty much dangerous maneuver – the glider doesn’t
have any specific control surface which would effectively make it recover from a
flat spin. Flat spin occurs especially when the center of gravity is
moved dangerously far aft (towards the back of the glider) so to achieve this
there was a sandbag strapped to the back of the
fuselage and there was a rope which went from the back to the cockpit so
that the pilots could enter the flat spin, then pull a rope, make the sand
fly away and then the glider regained its its a proper center of gravity
position. Obviously as strange as it may sound it worked,
so after entering the flat spin the rope tangled somewhere and the pilot was
unable to release the ballast from the back and therefore the glider was in a
constant flat spin. Pilot somehow managed to recover, it is said that it was
literally few meters above the ground. I didn’t know. But it was so emotional a
moment that the pilot doesn’t remember how did he recover and this is pretty bad because if he remembered we would have the answered how
to save ourselves from pretty… well very dangerous situation and it would be
interesting to know how he did it. Anyway after all those tests the glider was
named the SZD-9 bis Bocian and brought into production the first
version was called Bocian 1A, there were ten of them made. Then we had a version
1b with larger horizontal stabilizer and 11 made. Then the wings were made
less swept forward and there was a different elevator with – trimmer this
version was called 1C and was produced in 40 craft. Then there was a version 1D,
basically it accommodated a larger wheel and there was a mass production of 186
gliders and finally in 1967 there was the Bocian 1E – this is the version
which is still in use and this was glider modified to suit mainly the
training purpose not the record flights in a two-seater version. It was well less
curvaceous as we may look at it the tailplane and the edges
of the wings were more rectangular they had straight edges as we see here
this is the earlier version of the tailplane and this is the Bocian 1E. A difference in shape. The wingspan was a little shorter but the process of
production was made much easier. Also this glider accommodated shock absorbed
wheel and the instrument panel was placed on rubber bushings so that it
would shake less. As we talk of training this was the glider which had
short flights but many takeoffs and landings of various quality one after
another during the training session. All those changes made the weight of the
glider increase, here you can see the weight of particular versions of Bocian, eventually it weighed more than the ultralight airplane but it was also
very durable. There was an episode of of test flight of the version 1E which had
to prove that the glider with extended dive breaks does not go over it’s never
excess speed which was 200 km/h and the glider during this test achieved the
speed of 300 km/h, safely recovered and landed and what turned out
is that the test was mistakenly performed with the dive brakes closed
instead of open. Pretty much a failure but this glider sustained it with no
problem – it was very durable, very robust heavy glider, very stable therefore. But it was hard to stop it on the ground because it had drum brake on the wheel
which was taken from a motorbike which was limited to 45 km/h and weight – I
don’t know – 60 or 80 kg so it was not best brake for the glider, but this
was the way the industry worked those days. The Bocian 1E was
advertised during the World Gliding Championship in city of Leszno
in 1968. Many potential customers were taken as passengers,
pilots showed the performance of the glider which was pretty high because the
glider was certified for aerobatics and it made pretty good impression. It turned
out to be an export hit of Polish glider works. Out of 670 Bocian gliders made half of them were exported and here next to me you can now
see the list of 27 countries which bought the Bocian glider. It was
pretty much of a success. Also here you can see the performance data of
Bocian glider but obviously this is a data of the new glider. What am I doing
here is presenting history not teaching how to fly so if anyone is about to fly
Bocian glider then refer to Pilot’s Manual, to Operating Manual and see what
restrictions are now on the specific glider
you are about to fly. As a new glider Bocian was certified for cloud soaring. Flying next to clouds which are storm clouds
creates some danger of lightning strike so therefore this glider had like
earthing brushes on the edges of the wings which made electrical potentials
between the glider and the surrounding atmosphere more even – this is how I could
describe it. So this is one certification: to fly in clouds. It was also certified for flying at night, it could be equipped with lights
on the tail plane and on the wing edges there was only one flaw that if the
night flight was about to be a training flight then Bocian had to be equipped
with a second instrument panel for the back cockpit which was not standard and
was not so easy to fit. Bocian was also certified for
aerobatics, it had durability of up to plus 6 and minus 3g with pretty much safety
limit until the destroying acceleration was met so pretty safe feature
again. And it had had very large cockpit so if you were about to perform a
high-altitude flight, which was done, there was no problem to have massive
clothing for pilots and to accommodate radio equipment and oxygen installation.
Those high sideboards of the cockpit have one interesting feature
500 first Bocian gliders have solid boards while further craft have steps which
make it easier to get inside. Here you can see the layout of
the cockpit with standard instrumentation. All the flight controls
are also available for the instructor in the second cockpit. Inside the wings
there are two massive storage compartments which are accessible in
flight from the second cockpit so it’s a nice place, it’s easy to accommodate a
canopy cover or parachute covers inside or anything else – there are no push rods
no flight controls to be interrupted by these elements which are stored in these
compartments. Here you can see the Bocian glider with no wings and you can see clearly right through the fuselage – here were those storage spaces –
also here you can see the tailplane with horizontal stabilizer taken away,
it’s important when you carry the horizontal stabilizer to keep the
control surfaces even with the rest of the stabilizer so that you don’t damage
the trimmer Bowden cable. It sometimes happened. It is also worth
noticing that the canopy of Bocian glider changed during production – first
it had separate small windscreen and then the opening part and the part
sliding to the back for the second cockpit. Eventually it had one single
part canopy, opening to the side for the front cockpit and canopy sliding to the
back for the second one, but the front canopy could be opened, closed and
jettisoned in an emergency from the
front as from the second cockpit. Interesting feature. I’d like also to
have a quick look at the seatbelts of the glider. This was the same
principle and is a Jastrząb but these were properly designed so that they
would not unbuckle on their own. It was only important not to pull
too hard on this red square element because you could break this metal bar
which blocked the harness. Up until 1970 Bocian gliders set 29
World Records in different categories this is in itself a record because no
other single type of a glider achieved so much. One most noticeable flight is
the altitude record by Stanisław Józefczak – the flight took place on
November 5th, 1966 with the altitude of 12,560 meters with
altitude gain of 11680 meters. A great achievement! Honestly. The very successful Bocian
glider had many modifications, there were versions with engine, there were versions
designed to be flying laboratories, there were versions which were for high
performance flights but I’m going to tell you once about all those
modifications of Bocian glider and as for now I can leave you only with one
question: Why didn’t anyone make a Bocian out of carbon or other laminate? See you
next week in another episode of Vintage Sky. I’m Marek, thanks for watching!

7 Comments on “SZD-9 bis Bocian – the immortal glider [Vintage Sky]”

  1. Oto trzeci z sześciu angielskich odcinków, które kiedyś powstały i teraz są publikowane. Po kolejnych trzech nowy odcinek polski – o samolocie, na którego historię wiele osób czeka sądząc po komentarzach.

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