Taurus glider for sale

On Tuesday, May 21, 2019 at 11:15:21 AM UTC-7, ripacheco1967 wrote:
Don't scare me now.
50ºC (122ºF) is VERY EASY to reach in Florida.
You mean to tell me all those trailers sitting out in Florida are slowly baking their gliders into oblivion?

Keep in mind that I was using SC-14 resin as an example, and although likely similar to the SC-14, I don't know exactly which resin glider manufacturers use.
Realistically, short exposure to 50 C while in the trailer (not under load) won't do major damage the glider. However, at significantly higher temperatures or under load, some damage might occur.

UV light causes widespread electron jumps due to its short wavelength (without high enough quantum energies that they have the same effect as XRays/Gamma radiation) and hence does not readily penetrate anything. So, although composites may be damaged if directly subjected to UV light, any thin layer of anything between the structural composite and UV light will be sufficient, it doesn't need to be white.

Thomas

On Tuesday, May 21, 2019 at 12:15:21 PM UTC-6, ripacheco1967 wrote:
Don't scare me now.
50ºC (122ºF) is VERY EASY to reach in Florida.
You mean to tell me all those trailers sitting out in Florida are slowly baking their gliders into oblivion?

No.

Tg of MGS epoxy, which most sailplane manufacturers use when post cured, is around 200 deg F.

Mike

My thoughts are.......UV degradation of the fibers is the prime reason for the white coating (to reduce UV getting to fibers).
Ever see synthetic ropes out in UV? Most are white, but the UV destroyes them, thus strength goes to poop. Same for a lot of plastic woven tarps.
Not saying I am correct, just some observations.....

On Tuesday, May 21, 2019 at 11:16:45 AM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
My thoughts are.......UV degradation of the fibers is the prime reason for the white coating (to reduce UV getting to fibers).
Ever see synthetic ropes out in UV? Most are white, but the UV destroyes them, thus strength goes to poop. Same for a lot of plastic woven tarps.
Not saying I am correct, just some observations.....

It's not the fibers, well not with fiberglass and carbon per-se, it's the epoxy resin that is the issue, including how failing epoxy causes the reinforcing fibers to break/degrade. Epoxy is highly prone to UV dammage, it sucks.

And yes the white is also needed to keep the temperature down.

Hard to say there is a "prime reason" when addressing both UV exposure of the epoxy and high reflectivity to keep temperature low are both necessary.

Thomas Greenhill wrote on 5/21/2019 10:04 AM:
This is also why wise owners tend to prefer fiberglass-top trailers over metal ones in places that get very hot. As you can imagine, the inside of a metal trailer might easily exceed 50 degrees C (122 deg f) on a hot summer day.

Why won't that happen to a fiberglass top trailer? The ones I had got plenty hot
inside.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf

Trailer tops are made from polyester resins (like boat hulls) - different animal.

On 2019/05/21 19:04, Thomas Greenhill wrote:

If this taurus were indeed exposed to high enough temperatures for long enough to distort or melt the canopy, I would definitely argue that it has significant composites damage.

I think we can accept that most FRP gliders have a "service limit" of
maximum temperature under load of somewhere between 80C and 200C. This
is quite low but more than adequate for purposes, even for flying in the
desert conditions.

But that is not quite the same case as the damaged Taurus. The only
relevant information I could find on Google was one comment was from
this link
https://www.permabond.com/2011/11/10...ant-adhesives/

"Most adhesives can resist higher temperatures than what is listed as
the service temperature for short periods of time providing adhesion to
the substrate is high, and the stress is low."

Is that Taurus safe to fly?
Is there any means of testing the structure to determine if it has
suffered permanent damage?

I can understand why the manufacturer says "NO". The potential of a
liability claim from a future owner is huge, even if the future event
was not related to this damage, potential legal costs would be enough to
make the lawyers veto anything the engineers might say.

But if it was YOUR money invested in the aircraft would YOU fly it?

Ian


PS: I know of a few gliders that were damaged in fires, repaired and
returned to service. The repairs were done by experience professionals
and included post repair heat curing and post repair structural load
testing. These aircraft are still flying today, decades later.

Extract from engineering ........ has already shared info on the aircraft's destruction, so what I'd like to do here is to outline the structural concept of the Taurus Motorglider.

Taurus is constructed using the Scheufler (Hexion) L285 epoxy resin system, which is cured at 62 degC (145 F).

I attach the datasheet.

Essentially any long-term exposure to above +80 degC (175 F) or short term exposure to +90 degC (195 F) ambient temperature renders the material compromised in it's strength and is considered non-airworthy.......