SZD-36 Cobra 15

A friend is considering purchasing a SZD-36 Cobra 15 glider. Comments
from anyone having owned or flown this model aircraft would be
appreciated.

Terry/DG800B

Hi Terry,

I think that it is the type owned by Matthew Sawhill in Ankeny, Iowa. He
would be a good reference. ... Or is it his glider that is for sale? Did
he move up to something else?

Paul Remde

wrote in message
...
A friend is considering purchasing a SZD-36 Cobra 15 glider. Comments
from anyone having owned or flown this model aircraft would be
appreciated.

Terry/DG800B

Hi Terry,

You could try Scott Penrose of Gliding Club of Victoria (Australia)
email . He has owned and flown a Cobra 15 (VH-GJS)
for a couple of years.

Regards,

Geoff Vincent
Grampians Soaring Club

On Sat, 26 Jul 2008 02:14:20 GMT, "Paul Remde" wrote:

Hi Terry,

I think that it is the type owned by Matthew Sawhill in Ankeny, Iowa. He
would be a good reference. ... Or is it his glider that is for sale? Did
he move up to something else?

Paul Remde

wrote in message
...
A friend is considering purchasing a SZD-36 Cobra 15 glider. Comments
from anyone having owned or flown this model aircraft would be
appreciated.

Terry/DG800B

On Jul 25, 9:14 pm, "Paul Remde" wrote:
Hi Terry,

I think that it is the type owned by Matthew Sawhill in Ankeny, Iowa. He
would be a good reference. ... Or is it his glider that is for sale? Did
he move up to something else?

Paul Remde

wrote in message

...

A friend is considering purchasing a SZD-36 Cobra 15 glider. Comments
from anyone having owned or flown this model aircraft would be
appreciated.

Terry/DG800B

Sawhill flies a Foka 4.

On Jul 25, 10:01*pm, " terry-
wrote:
A friend is considering purchasing a SZD-36 Cobra 15 glider. Comments
from anyone having owned or flown this model aircraft would be
appreciated.

Terry/DG800B

Please make sure that you have the translated copy of Polish
Maintenance Manual from SZD!
It is a beautiful wooden glider however as with any construction it
requires preventative maintenance. There has been an accident in
Alabama where a roman screw retracted from the lower spar (due to a
wear of supporting bushing) and wings collapsed during a high speed
pass. Maintenance manual calls for periodical replacement of those
parts and such a glider would not have been airworthy in Poland.

Regards

GK

On Sat, 26 Jul 2008 07:17:44 -0700, GK wrote:

There has been an accident in
Alabama where a roman screw retracted from the lower spar (due to a
wear of supporting bushing) and wings collapsed during a high speed
pass.

What is a roman screw?
Is it the same type of wing fixing that the SHK used?

I've not seen the term before and a web search failed to find a suitable
definition.


--
martin@ | Martin Gregorie
gregorie. |
org | Zappa fan & glider pilot

On Jul 26, 2:45*pm, Martin Gregorie
wrote:
On Sat, 26 Jul 2008 07:17:44 -0700, GK wrote:
There has been an accident in
Alabama where a roman screw retracted from the lower spar (due to a
wear of supporting bushing) and wings collapsed during a high speed
pass.

What is a roman screw?
Is it the same type of wing fixing that the SHK used?

I've not seen the term before and a web search failed to find a suitable
definition.

--
martin@ * | Martin Gregorie
gregorie. |
org * * * | Zappa fan & glider pilot

- http://pl.wikipedia.org/wiki/%C5%9Aruba_rzymska

On Jul 26, 2:19 pm, GK wrote:
On Jul 26, 2:45 pm, Martin Gregorie



wrote:
On Sat, 26 Jul 2008 07:17:44 -0700, GK wrote:
There has been an accident in
Alabama where a roman screw retracted from the lower spar (due to a
wear of supporting bushing) and wings collapsed during a high speed
pass.

What is a roman screw?
Is it the same type of wing fixing that the SHK used?

I've not seen the term before and a web search failed to find a suitable
definition.

--
martin@ | Martin Gregorie
gregorie. |
org | Zappa fan & glider pilot

-http://pl.wikipedia.org/wiki/%C5%9Aruba_rzymska

In the USA it would be called a Turnbuckle.

On Sat, 26 Jul 2008 15:07:12 -0700, Tim Taylor wrote:

On Jul 26, 2:19 pm, GK wrote:
On Jul 26, 2:45 pm, Martin Gregorie



wrote:
On Sat, 26 Jul 2008 07:17:44 -0700, GK wrote:
There has been an accident in
Alabama where a roman screw retracted from the lower spar (due to a
wear of supporting bushing) and wings collapsed during a high speed
pass.

What is a roman screw?
Is it the same type of wing fixing that the SHK used?

I've not seen the term before and a web search failed to find a suitable
definition.

--
martin@ | Martin Gregorie
gregorie. |
org | Zappa fan & glider pilot

-http://pl.wikipedia.org/wiki/%C5%9Aruba_rzymska

In the USA it would be called a Turnbuckle.

Same here, but how, exactly, does that attach the wings? I can understand
that it might pull them together and onto the fuselage pickup pins, but
what locks the spars together?

Martin Simon's 3-view of the Cobra shows the spars apparently meeting at
the fuselage centre line and some sort of circular hatch above their
meeting point: that's why I asked if the Cobra used a similar mechanism to
the SHK.


--
martin@ | Martin Gregorie
gregorie. |
org | Zappa fan & glider pilot

I think there is a misunderstanding. There are two main screws at the
spar but non of the similar to the linked element.

On of them is vertical and similar to the IS28B2 main pin mechanism.
This attach and secure the two wings. It's unlikely to have failure
here.

Second one is horizontal behind the pilots head. This mechanism adjust
the wings horizontal play. This has to be fastened and secured after
assembly. One of my friend took off without this step... I can imagine
that high stress together with this mistake can be deadly.

Cobra is a robust plane, designed for aerobatics. Because of this
purpose wings are really heavy. Flight characteristics are friendly,
no bad habit like at stdCirrus (all moving tail). Performance is
around dry stdCirrus, stdJantar.

Wheel retraction system is a tricky rotating mechanism, careful
maintenance is needed for proper operation.

Instrument panel is small, limited space for instruments.

Baggage compartment is big, XC equipment can fit easily.

Not all Cobra is fired with CG hook! Winch launch with nose hook is
much lower.

It's a wooden plane with some composite material. Surface waveness can
change a lot by temperature, humidity. So don't worry if your nice
Cobra looks ugly one day, it will be nice again after a while

Conenction mechanism below the control stick is a bit weak. It's a
screw adjusted conical system and as dusk usually get's into that
place regular adjustment is needed. Usually this adjustment is a
tricky balancing between low control forces and small play.

If you are interested about some pictures here is my Cobra page:

http://bauerj.fw.hu/Cobra15/