First Glider

On Wed, 08 Sep 2004 16:46:18 -0700, Eric Greenwell wrote:

Mark James Boyd wrote:

Stay away from wooden gliders. You don't know if they've
had "good care" or "proper storage" in the past, and
this may be very hard to determine.

All aircraft can suffer from improper care and storage. That's why you
inspect them.

I'm reminded of the Citabrias guys with all the inspection
holes in their wings. It didn't matter if you kept
yours in a super dry hanger its whole life, and never flew it.


We had a Citabria that neeeded inspection. As I recall, the AD wasn't
due to rot, but some Citabrias were found to have damaged spars.
Eventually, but after lots of Citabrias were inspected, it was found
that some (all?) of the original ones that started the AD were damaged
by things like blowing over and not having repairs done, or not logged.
I don't think it was primarily a wood issue in the end. We had to
replace some little nails.

The wooden AD meant you had to cut holes in the
wings.

Hey, it was just fabric. Easy to do, easy to fix. Try that with a metal
or fiberglass glider.

Wood doesn't fatigue like metal or fiberglass, but the metal fittings
can. These are easy to inspect. Regardless, you should have whatever you
buy inspected first by a person that knows the material and the aircraft.

AFAIK fibreglass doesn't suffer from fatigue either
In Australia there has been an ongoing fatigue test on a Janus wing,
with no detectable deterioration over many thousands of hours of
testing.
Cheers, John G.

IIRC a recent article in technical soaring suggested flying lifespans of
around 250 000 hours for the average plastic ship.

Ian

"John Giddy" wrote in message
. ..
On Wed, 08 Sep 2004 16:46:18 -0700, Eric Greenwell wrote:

Mark James Boyd wrote:

Stay away from wooden gliders. You don't know if they've
had "good care" or "proper storage" in the past, and
this may be very hard to determine.

All aircraft can suffer from improper care and storage. That's why you
inspect them.

I'm reminded of the Citabrias guys with all the inspection
holes in their wings. It didn't matter if you kept
yours in a super dry hanger its whole life, and never flew it.


We had a Citabria that neeeded inspection. As I recall, the AD wasn't
due to rot, but some Citabrias were found to have damaged spars.
Eventually, but after lots of Citabrias were inspected, it was found
that some (all?) of the original ones that started the AD were damaged
by things like blowing over and not having repairs done, or not logged.
I don't think it was primarily a wood issue in the end. We had to
replace some little nails.

The wooden AD meant you had to cut holes in the
wings.

Hey, it was just fabric. Easy to do, easy to fix. Try that with a metal
or fiberglass glider.

Wood doesn't fatigue like metal or fiberglass, but the metal fittings
can. These are easy to inspect. Regardless, you should have whatever you
buy inspected first by a person that knows the material and the
aircraft.

AFAIK fibreglass doesn't suffer from fatigue either
In Australia there has been an ongoing fatigue test on a Janus wing,
with no detectable deterioration over many thousands of hours of
testing.
Cheers, John G.

Tim Mara wrote:
The next time someone sneers at a wooden sailplane, remind them that it is
made of a unidirectional reinforced laminated composite material consisting
of micro-tubular fibres embedded in a long chain polymer matrix and having a
near infinite fatigue life.
tim



Stay away from wooden gliders. You don't know if they've
had "good care" or "proper storage" in the past, and
this may be very hard to determine.

------------+
Mark J. Boyd




And anyone who thinks they are not tough has not looked at the vintage
Bergfalkes and K13 grinding around the circuits all over the world. We have one
Bergie over 17,000 flights/9000 hours and going strong. Damage history is
extensive too - but easy to repair, and even poorly executed repairs from
previous lives have held up remarkably.

On a weak day they give a nice aerial view of the glass sitting on the runway...

Jeff Runciman wrote in message news:...
Thanks for all of the advise. I may have to get a
glider in between 30 and 35 ld. I am concerned about
getting in deeper than I should and not having fun.
It is possible that I should get a club class glider
due to my hang gliding experience (tighter turn radius?).
A PW5 or Russia may be an answer. I will be spending
sometime dual in a Lark. Two questions: What happened
to Russia Sailplanes? Were there any other gliders
that compare to the PW5 and the AC5?

Thank you again for your help.

Jeff


Jeff:

I had approx. 60 hours total gliding experience when
I bought my first glider, a Blanik L33 Solo. My hours
including time in a 2-33, 1-26 and a Lark.

The L33 was a nice 1st ship. Very easy to fly, no retractable
gear, L/D of 32.5/1 and it climbed pretty well. I was
able to tie it down because it was metal and the cockpit
was very large. I flew it for a year and sold it to
a club for their operations. My current glider is a
Genesis 2, which has a 43/1 L/D and retractable gear.
It is also easy to fly, but I think that if I had bought
it as a first glider it may have been too much for
me to handle.
GORDY

Tim Mara wrote:
The next time someone sneers at a wooden sailplane, remind them that it is
made of a unidirectional reinforced laminated composite material consisting
of micro-tubular fibres embedded in a long chain polymer matrix and having a
near infinite fatigue life.
tim

LOL! Yep. And vulnerable to Isoptera. And dihyrogenoxate(?). Big names,
simple common problems. Make a glider for $30k with anything other than
modern materials that has the polar of a Sparrowhawk, and I'll be happy
to bow out.

Not sneering at wood. For those who know it well and can do
"proper care and storage," good for them. But wood just isn't a common
aircraft material anymore.
--

------------+
Mark J. Boyd

So it doesn't always matter how good YOU traet it either.
Stay away from wood. There's a reason it is uncommon
in current aircraft manufacturing.
--

------------+
Mark J. Boyd

One of the reasons is that wood changes dimensionally when the weather
changes. And if you take a wooden aircraft to a very dry location, the
dimensional change can cause all manner of structural problems.

Another reason for sailplanes is the high labour cost of cutting out and
gluing thousands of wooden bits. Not much less than the costs involved
in making a glass ship, which can be made with much better control of
wing profile and hence performance.
--
Mike Lindsay

Mark James Boyd wrote:
...
Stay away from wood. There's a reason it is uncommon
in current aircraft manufacturing.
...

Maybe uncommon in the USA, in France the most common 4 seats
airplane is probably the Robin DR400 which is, at least for the
wings, made of wood and fabric. Also widely used as a tow plane.

Mark James Boyd wrote:
Stay away from wood. There's a reason it is uncommon
in current aircraft manufacturing.

Yes there is......it's is more difficult to build compound shapes from wood,
more expensive to repeatedly make the same parts from wood when in composite
structures you simply need a mold, some cloth and a bucket of resin to
duplicate each part. Much of the same applies to metal aircraft and that's
why so many new designs, especially from smaller manufacturers choose
composites as well. That is not necessarily a reason to stay away from an
aircraft that was, already painstakingly constructed of wood, are still
airworthy and will be for years to come. You may even find many of your
recent composite aircraft STILL have some wood used in areas as the core for
some bulkheads etc...doesn't mean these should be condemned as well.
tim

"you can trust a tree"--George Coder, in Soaring ad for Standard Austria, circa
1967

the Robin DR400 which is, at least for the
wings, made of wood and fabric.

And very good woodwork it is. Interestingly tho the wheel panta are carbon
fiber! Go figure.

Robert Mudd
Oh, yes the full George coder quote is "Woods still good, you can trust a tree"