Taurus glider for sale

I bought a G-103 that had been in a hangar fire in Georgia, Peach State Club. We needed a left wing and the photos showed what looked like a useable left wing on a fuselage with canopies that had been hot enough to melt the canopies. Both canopied draped down like a tarp, but it was the new shape of the plexiglass! The outer skin of the left wing top was blistered and had to be replaced, but the spar caps were undamaged. I figured the wing hadn’t been in 350 degree environment long enough to affect the more dense spar cap. We proof-loaded the wing and it took 5.3 G’s with flying colors! That was some 25 years ago and that ship is still flying today!
Just a little data point about how much heat a fiberglass structure can take,
JJ

On Friday, April 19, 2019 at 7:10:14 AM UTC-7, wrote:
I bought a G-103 that had been in a hangar fire in Georgia, Peach State Club. We needed a left wing and the photos showed what looked like a useable left wing on a fuselage with canopies that had been hot enough to melt the canopies. Both canopied draped down like a tarp, but it was the new shape of the plexiglass! The outer skin of the left wing top was blistered and had to be replaced, but the spar caps were undamaged. I figured the wing hadn’t been in 350 degree environment long enough to affect the more dense spar cap. We proof-loaded the wing and it took 5.3 G’s with flying colors! That was some 25 years ago and that ship is still flying today!
Just a little data point about how much heat a fiberglass structure can take,
JJ

I remember seeing those Peach State gliders tied down at Williamson after the fire.
Have also flown an ASH25Mi that was previously an ASH25M and involved in an engine compartment fire. The factory replaced the fuselage, worked on the wings, got it flying as good as ever.
Jim

On 4/19/2019 8:10 AM, wrote:
I bought a G-103 that had been in a hangar fire in Georgia, Peach State
Club. We needed a left wing and the photos showed what looked like a
useable left wing on a fuselage with canopies that had been hot enough to
melt the canopies. Both canopied draped down like a tarp, but it was the
new shape of the plexiglass! The outer skin of the left wing top was
blistered and had to be replaced, but the spar caps were undamaged. I
figured the wing hadn’t been in 350 degree environment long enough to
affect the more dense spar cap. We proof-loaded the wing and it took 5.3
G’s with flying colors! That was some 25 years ago and that ship is still
flying today! Just a little data point about how much heat a fiberglass
structure can take, JJ

WARNING: Engineering humor nearby!!!

Good thing the statute of limitations has expired, JJ, cuz the engineer in me
likes how you thought - and acted on the courage of your convictions - all
those years ago. Just like 'industry big boys' and 'reasonable government
safety-regulating-minions' regularly do in aviation-land - one test is worth a
thousand considered opinions. (Take *that* FUD-Merchants and [sometimes]
lazy/fearful manufacturers!)

Now back to regularly-scheduled programming.

:-)

Bob W.


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On Friday, April 19, 2019 at 7:10:14 AM UTC-7, wrote:
I bought a G-103 that had been in a hangar fire in Georgia, Peach State Club. We needed a left wing and the photos showed what looked like a useable left wing on a fuselage with canopies that had been hot enough to melt the canopies. Both canopied draped down like a tarp, but it was the new shape of the plexiglass! The outer skin of the left wing top was blistered and had to be replaced, but the spar caps were undamaged. I figured the wing hadn’t been in 350 degree environment long enough to affect the more dense spar cap. We proof-loaded the wing and it took 5.3 G’s with flying colors! That was some 25 years ago and that ship is still flying today!
Just a little data point about how much heat a fiberglass structure can take,
JJ

There is a reason why fiberglass gliders are painted white: they can't withstand high temperatures. There is a critical temperature called the "glass transition temperature" which is where the plastic starts transitioning from a solid into a liquid. A typical glass transition temp for fiberglass is 100C, well below the temps seen in that hanger fire. The fact that they canopy melted demonstrates that the temp was that high for some period of time..
https://en.wikipedia.org/wiki/Glass_transition

On Saturday, April 20, 2019 at 11:07:40 PM UTC-7, 2G wrote:

There is a reason why fiberglass gliders are painted white: they can't withstand high temperatures...

It's a bit more complicated than that. We could have blue or black or red composite gliders if we really wanted. Unsurprisingly it comes down to economics.

There are epoxy resin systems that can be used to achieve a Tg well above those achieved by darkly colored surfaces exposed to direct sunlight. We're using one such system right now on some aircraft parts that for a variety of reasons must be painted black.

However, compared to the MGS285 system that has become the de facto standard for European sailplane manufacture, those high-temperature systems are generally some or all of:

* More expensive
* Harder to mix and use
* More toxic
* More sensitizing

Furthermore, for some such systems, the parts must be subjected to elevated post-cure just to make them tough enough to demold. And then they must get an even hotter post-cure after all the parts are assembled.

All of these reasons that high-temperature systems are a pain to use make them more expensive to use, and for no easily justified reason.

There is a critical temperature called the "glass transition temperature" which is where the plastic starts transitioning from a solid into a liquid.. A typical glass transition temp for fiberglass is 100C, well below the temps seen in that hanger fire. The fact that they canopy melted demonstrates that the temp was that high for some period of time.
https://en.wikipedia.org/wiki/Glass_transition

Our tests have shown that exceeding Tg does not necessarily weaken a composite structure; depending on a variety of factors it will quite likely regain all its former strength and stiffness once it cools down. Furthermore, the melting of the canopy is not necessarily an accurate indicator of the temperatures reached by the rest of the structure; clear acrylic plastic absorbs a lot of wavelengths that reflect off of a white painted surface.

--Bob K.

On Sunday, April 21, 2019 at 8:04:21 AM UTC-7, Bob Kuykendall wrote:
On Saturday, April 20, 2019 at 11:07:40 PM UTC-7, 2G wrote:

There is a reason why fiberglass gliders are painted white: they can't withstand high temperatures...

It's a bit more complicated than that. We could have blue or black or red composite gliders if we really wanted. Unsurprisingly it comes down to economics.

There are epoxy resin systems that can be used to achieve a Tg well above those achieved by darkly colored surfaces exposed to direct sunlight. We're using one such system right now on some aircraft parts that for a variety of reasons must be painted black.

However, compared to the MGS285 system that has become the de facto standard for European sailplane manufacture, those high-temperature systems are generally some or all of:

* More expensive
* Harder to mix and use
* More toxic
* More sensitizing

Furthermore, for some such systems, the parts must be subjected to elevated post-cure just to make them tough enough to demold. And then they must get an even hotter post-cure after all the parts are assembled.

All of these reasons that high-temperature systems are a pain to use make them more expensive to use, and for no easily justified reason.

There is a critical temperature called the "glass transition temperature" which is where the plastic starts transitioning from a solid into a liquid. A typical glass transition temp for fiberglass is 100C, well below the temps seen in that hanger fire. The fact that they canopy melted demonstrates that the temp was that high for some period of time.
https://en.wikipedia.org/wiki/Glass_transition

Our tests have shown that exceeding Tg does not necessarily weaken a composite structure; depending on a variety of factors it will quite likely regain all its former strength and stiffness once it cools down. Furthermore, the melting of the canopy is not necessarily an accurate indicator of the temperatures reached by the rest of the structure; clear acrylic plastic absorbs a lot of wavelengths that reflect off of a white painted surface.

--Bob K.

Yes, it is always more complicated than what most people are interested in reading. But in the case of this glider, the manufacturer clearly considered it to be unairworthy, period. Further, without having the glider fully instrumented with thermocouples, no one can say how hot, and for how long, each part of the glider got. Absent such data, the only safe course of action is to declare it unairworthy unless the manufacturer details an inspection and test regimen that can assure the glider's safety and continued airworthiness.

Additionally, changing the serial number is a blatant effort to disguise the damage history of the glider and constitutes fraud, in my opinion.

Tom

Speaking of complicated, I have direct knowledge of this one, and it's a lot more complicated than you realize. Just know that the manufacturer declaring it's unairworthy has nothing to do with anything, other than them not getting their way. I'll leave it at that.

On Sunday, April 21, 2019 at 11:15:25 AM UTC-7, 2G wrote:

Additionally, changing the serial number is a blatant effort to disguise the damage history of the glider and constitutes fraud, in my opinion.

We've covered that. The serial number in the FAAs record for the new N-number is the correct one for that airframe. The serial number in the ad is close enough to be explained by a mere typo.

--Bob K.

On Sunday, April 21, 2019 at 11:04:21 AM UTC-4, Bob Kuykendall wrote:
....
Our tests have shown that exceeding Tg does not necessarily weaken a composite structure; depending on a variety of factors it will quite likely regain all its former strength and stiffness once it cools down.

Would the wings and fuselage sag and permanently deform in a hangar fire? Worse if only one wingtip was supported.

I was hoping JJ would post up about his fire damage repairs.

Right now at the HP shop we're doing a skunky project involving high-temperature epoxy systems. As part of it, we did some test on more pedestrian epoxies of the sort typically used in gliders. They appear to demonstrate that you can get them well above Tg and they'll still recover full strength when they cool down. Of course, how far above Tg you can safely get is hard to quantify.

...They are shocked that it has not been destroyed...

A corporate entity based in a former Soviet republic is surprised that airworthiness authorities did not seize and destroy the personal property of a private citizen?

Shocked, I tell you, Shocked!

(Bogie never did say "Play it again, Sam.")

--Bob K.