Aircraft slow cooking

[Doug Bailey]

I have a glider showing up in late Q4. It's my first owned aircraft of any kind, so I have a long list of possibly dumb questions. The top of my list right now is "where to keep it?".

It's going to have a new Cobra trailer with a fiberglass top. I'm lucky enough to have some space at home and so my options are to park it at my place in the open or build a shelter/garage ($$$$), park it at the airport in the open or park it at the airport with cloth covers for the trailer ($$). Does parking a glider in the trailer in the California sun screw it up? Does slow cooking mess up the laminate or the instrument screens, or fabrics/finishes? Do I need to worry about bugs and beasties making their home in the trailer or in the glider? Do most folks consider the trailer aesthetics to be "disposable" - basically just decide to live with the sun damage to gelcoat?

[Mark628CA]

Considering the hundreds of thousands of sailplanes that have been stored in trailers worldwide over the last sixty years or so, I don't think you have a lot to worry about. As long as you control moisture and provide some air circulation and regularly inspect the aircraft for potential degradation due to environmental conditions inside the trailer, you shouldn't have a problem. Fiberglass/gelcoat trailer tops do experience degradation, but an annual wax job with UV resistant coatings can minimize the damage. Polish it every couple of years and apply new wax. It will still look great after a decade or more. Most importantly, haul the damn glider out and fly it as often as you can. Gliders need love and attention. Kinda like a wife. but with fewer arguments.

[Steve Koerner]

On Tuesday, August 15, 2023 at 6:49:48 PM UTC-7, Mark628CA wrote:

Learned in Phoenix, AZ: Definitely keep it in the trailer to protect the finish from sunlight damage. While in the trailer, keep both sides of the canopy latched to preserve the canopy frame fit. Keep locks on the ailerons and flaps to protect the curvature of precurved mylar gap seals. Gliders are otherwise heat tolerant by design. Best to store parachute and batteries indoors as they are somewhat heat impacted.

[youngbl...@gmail.com]

On Tuesday, August 15, 2023 at 8:46:40 PM UTC-4, Doug Bailey wrote:
> I have a glider showing up in late Q4. It's my first owned aircraft of any kind, so I have a long list of possibly dumb questions. The top of my list right now is "where to keep it?".
>
> It's going to have a new Cobra trailer with a fiberglass top. I'm lucky enough to have some space at home and so my options are to park it at my place in the open or build a shelter/garage ($$$$), park it at the airport in the open or park it at the airport with cloth covers for the trailer ($$). Does parking a glider in the trailer in the California sun screw it up? Does slow cooking mess up the laminate or the instrument screens, or fabrics/finishes? Do I need to worry about bugs and beasties making their home in the trailer or in the glider? Do most folks consider the trailer aesthetics to be "disposable" - basically just decide to live with the sun damage to gelcoat?

Doug, what kind of glider are you getting and is it poly or gel finished? I keep my trailers inside a warehouse when not in use, and there are still periodic inspections that I do to check on the trailer or glider. Critters can and will get inside a trailer, mice can be nasty little devils and create havoc. You may think that your trailer is rodent and bug proof but still inspect often and close any void where things can enter the trailer. I keep my trailers covered even while in the warehouse, dirt and dust can be nasty as well. As far as the glider, you have been given good advice about polishing and keeping clean, good luck with the new ship and enjoy you glider. OBTP

[Eric Greenwell]

On Tuesday, August 15, 2023 at 5:46:40 PM UTC-7, Doug Bailey wrote:
> I have a glider showing up in late Q4. It's my first owned aircraft of any kind, so I have a long list of possibly dumb questions. The top of my list right now is "where to keep it?".
>
> It's going to have a new Cobra trailer with a fiberglass top. I'm lucky enough to have some space at home and so my options are to park it at my place in the open or build a shelter/garage ($$$$), park it at the airport in the open or park it at the airport with cloth covers for the trailer ($$). Does parking a glider in the trailer in the California sun screw it up? Does slow cooking mess up the laminate or the instrument screens, or fabrics/finishes? Do I need to worry about bugs and beasties making their home in the trailer or in the glider? Do most folks consider the trailer aesthetics to be "disposable" - basically just decide to live with the sun damage to gelcoat?

Where are you? Your potential problems are quite different in a dry desert climate vs a humid coastal climate, or Phoenix in the summer vs Montana in the winter.

[Dan Daly]

In his original post he says "...Does parking a glider in the trailer in the California sun screw it up?..."

[Doug Bailey]

I'm in Northern California - I trained with HSC in Hollister and if I decide to keep it at an airport, that's where it will be. The ramp storage there is in full sun.

[Hank Nixon]

If you have the option it is very good to have the trailer under cover. This reduces heating and moisture cycles which extends the life of both glider and trailer.
High heat cycles age the glider faster which shows up as shrink eventually affecting performance.
Moisture cycles affect finish adversely.
UH

[Doug Bailey]

Thanks for this. My approach to things I own is to keep them maintained and looking nice for the long haul. I'm not a "use it up and buy another one" kind of person. I'm familiar with the weather impacts on composite structures (yacht racing - same class, same boat for 20 years), hence the question. And physically, there's Ahrenius (chemical reactions double in speed every 10 degrees C, approximately) - so bad shit can happen "not much" then "all at once" if there's a thermal spike. I doubt that a modest 50C or 60C max temperature inside a glider trailer in the sun would be enough to test the glass transition temperatures of a glider's materials, but it probably is enough to increase the "creep" of anything under load. Bottom line - since the unit is new, now is the time to decide whether the trailer is adequate to protect it because damage will cumulate and could cumulate quickly at higher temperatures.

[Eric Greenwell]

OK, Hollister! There's a lot of glider pilots there, so those are the ones you should be talking to (not us random responders on RAS :^) ), or at least join their newsgroup. I suggest you order the trailer with paint instead of gel coat, just in case you have to park it outside. That is often true, even if you can find hangar to keep the glider assembled.

[John Sinclair]

I didn’t see anyone mentioning not to leave any food in the cockpit or even in the trailer at all! I’ve seen cockpit side pouch chewed open to get to a stick of gum left in the cockpit. Air vents in the trailer are a good idea, but must be screened to keep rodents out. A couple of 2” vents in the floor up front and another high on the trailer fin will let high temperatures out and help prevent high humidity build up in your trailers. Trailer tires should be covered to prevent weather cracking. During the wet season, it’s a good idea to open the trailer at least once every month and wing/fuselage saddles moved to air out any moisture buildup.
Outside storage is OK, but ship and trailer inside or at least under a shade is best.
JJ

[Dan Marotta]

Get a couple of portable car ports. Cut, trim, join to make a sun shade
long enough to park your trailer under.

https://www.amazon.com/Land-Guard-Carport-Canopy-10x20/dp/B0C4DKTJ3T/ref=sxin_15_sbv_search_btf?content-id=amzn1.sym.6cfa532e-9c8f-48d2-87a3-a61547a0d356%3Aamzn1.sym.6cfa532e-9c8f-48d2-87a3-a61547a0d356&cv_ct_cx=portable+carport&keywords=portable+carport&pd_rd_i=B0C4DKTJ3T&sbo=RZvfv%2F%2FHxDF%2BO5021pAnSA%3D%3D&sr=1-1-5190daf0-67e3-427c-bea6-c72c1df98776

Dan
5J

[AS]

On Wednesday, August 16, 2023 at 2:54:32 PM UTC-4, Dan Marotta wrote:
> Get a couple of portable car ports. Cut, trim, join to make a sun shade
> long enough to park your trailer under.
>
> https://www.amazon.com/Land-Guard-Carport-Canopy-10x20/dp/B0C4DKTJ3T/ref=sxin_15_sbv_search_btf?content-id=amzn1.sym.6cfa532e-9c8f-48d2-87a3-a61547a0d356%3Aamzn1.sym.6cfa532e-9c8f-48d2-87a3-a61547a0d356&cv_ct_cx=portable+carport&keywords=portable+carport&pd_rd_i=B0C4DKTJ3T&sbo=RZvfv%2F%2FHxDF%2BO5021pAnSA%3D%3D&sr=1-1-5190daf0-67e3-427c-bea6-c72c1df98776
>
> Dan
> 5J

Good idea, Dan but unmodified, this thing will take off faster than a toupee in a fan-factory!
It needs some serious ground anchors and the slip-fit tubing joints would need to be secured with a sheet-metal screw to keep them locked in place. The tarp may need to be re-made with some more UV-resistant awning material in short order. My friends in OH had a shelter for their trailers like this and the tarp material showed the effects of UV after just a few years.

Uli
'AS'

[Dan Marotta]

Yup, but better the tarp than the trailer.

That thing would not last long in Moriarty due to our winds but maybe in
CAlifornia with proper anchors.

Dan
5J

[andy l]

I wouldn't be quite so blasé about the prospect of 60 degrees inside the trailer. I'd be actually trying to avoand id it. Above that you might see shrinkage or patterning at the surface, and wave or shrinkage at the spar and other places

Excerpt from technical info on the resin system

This system meets the requirements for gliders and motor-gliders after post curing at 50 to 55 deg C (operational temperature -60 to +54 deg C) and for powered light aircraft when cured above 80 deg C (operational temperatures -60 to +72 deg C)

I don't know whether glider manufacturers post cure to higher for certain destinations.Might be worth a question

Apologies to anyone who sees this reply more than once, after I posted with the wrong account

On Wednesday, 16 August 2023 at 17:27:37 UTC+1, Doug Bailey wrote:
> On Wednesday, August 16, 2023 at 8:45:18 AM UTC-7, Hank Nixon wrote:

I doubt that a modest 50C or 60C max temperature inside a glider trailer in the sun would be enough to test the glass transition temperatures of a glider's materials, but ...

[Nicholas Kennedy]

Doug
My understanding is that UV can penetrate a Cobra Fiberglass top and reek havoc with the finish, sitting out int he sun.
I've seen here locally with a really damaged beyond belief LS6 That sat in a fiberglass cobra trailer in the sun.
If I were to leave a fiberglass top cobra out in the sun I would do the above advice on ventilation and rodent proofing and spend a afternoon with a big roll of foil backed bubble wrap and line the whole interior of the lid to try and UV proof it as much as possible..
I've seen this done and its not too hard to do
And of course really tie the trailer down and try to have your neighbors do the same.
It's seems the weather is getting stronger and wilder.
Nick
T

[John Galloway]

If it's not too late stump up the extra and get the metal topped Cobra.

[Doug Bailey]

I didn't choose the fiberglass version for cost reasons. I have a lot of experience with composites and I figured I could successfully repaint it, fix it etc myself when needed. I have had pretty much zero success painting aluminum (boat spars) - even with passivation and a zinc chromate undercoat, the paint seems to flake off regrettably soon. Also, I was guessing that the plastic would be more immune to rapid thermal cycling than metal. It never occured to me that the fiberglass top would be transparent to UV as Nicholas stated above. That's definitely something new to think about. I have seen a similar effect with boat halyards using fancy materials - UV-sensitive aramid core with a polyester jacket, for example. The polyester does not show any impact of UV, but meanwhile the load bearing core is rotten due to long exposure to UV that is not fully attenuated by the so-called protective cover. Nowadays I pull my halyards out after a regatta and store them below; breaking things is slow.

[mrop...@gmail.com]

The Cobra trailers have evolved over time. I don't know which year
fiberglass top Cobra/Komet trailers that Mark was referencing. The
early ones were single layered FRP versions as were the old Eberle
and Schroeder glass covered tube and semi-clamshell type trailers.
Those type trailers would let diffused light into the trailer, and
apparently some UV rays as well. The later Cobra fiberglass tops
are a two layer sandwich type construction (with a thin insulation
layer in between IIRC), and also have a black UV blocking paint
sprayed on the inside. If I open the front hatch on my trailer when
I'm out in the bright sunlight, the trailer is pitch black inside. I keep
my glider in the trailer, in a hangar in New York State. It does make
a long term difference in the condition of both the trailer and glider.
When it comes to storage, you get what you pay for.

Mike Opitz
RO

[Dan Marotta]

I did some more thinking on the car port idea. One could use a tarp or
two over the top of the trailer with some sort of spacers between the
trailer and the tarp and then staked down like a tent.

Better still, tie the tarp under the trailer.

Dan
5J

[Hank Nixon]

In the east I use flexible "greenhouse' type shelters to keep the trailers out of the sun and rain. They need to be well anchored. Cover life is about 3 years. This is MUCH better than leaving out it the elements. There are plenty of metal "garage " type shelters that are more durable at higher cost. A 14 foot wide by 10 foot high and 32 foot long shelter holds two 15 meter trailers. Source is Shelter Logic.
Leaving a glider and trailer worth more than 100 grand out in the weather is a really bad idea to me.
FWIW
UH

[AS]

I have seen a DIY-solution for blocking UV penetrating through the glass top of a Cobra trailer. The owner used some spray adhesive and glued simple house-hold aluminum foil into the top. Looked a bit 'Disco-Era-'like but last time I checked, UV doesn't go through Al-foil.

Uli
'AS'

[Eric Greenwell]

Here's another data point: my 28 year old painted aluminum top Cobra trailer has always been outside, uncovered, in eastern Washington State (Richland, WA - desert climate, mostly). I stopped waxing it 20 years ago, but I still wash it once or twice a year. It looks good, and would likely look very good if it was polished and waxed. Cobra did not paint the aluminum sheet used on the top, but purchased it already painted.

It is, apparently, a very high quality, durable paint. There's never been a need to repair or repaint the top, and I would get a metal one again. My choice might be different if I lived in a humid climate.

[youngbl...@gmail.com]

On Tuesday, August 15, 2023 at 8:46:40 PM UTC-4, Doug Bailey wrote:
> I have a glider showing up in late Q4. It's my first owned aircraft of any kind, so I have a long list of possibly dumb questions. The top of my list right now is "where to keep it?".
>
> It's going to have a new Cobra trailer with a fiberglass top. I'm lucky enough to have some space at home and so my options are to park it at my place in the open or build a shelter/garage ($$$$), park it at the airport in the open or park it at the airport with cloth covers for the trailer ($$). Does parking a glider in the trailer in the California sun screw it up? Does slow cooking mess up the laminate or the instrument screens, or fabrics/finishes? Do I need to worry about bugs and beasties making their home in the trailer or in the glider? Do most folks consider the trailer aesthetics to be "disposable" - basically just decide to live with the sun damage to gelcoat?

Doug, do yourself a favor and buy a used conex 40 foot would be great, and you can install a couple of air vents and a possible solar fan for temp control. I have used a 40' container several times and they last for years at a very affordable cost. If the airport will allow you to position the trailer at the location that is an added bonus.
I have an old Komet trailer for Eileen's ASW24, it looks great after about 30 years. I do keep it inside and it is buffed about every two years, have to make sure she has something to do in her spare time. Sleeping on the couch tonight! OBTP

[AS]

On Friday, August 18, 2023 at 1:49:52 PM UTC-4, Eric Greenwell wrote:
> Here's another data point: my 28 year old painted aluminum top Cobra trailer has always been outside, uncovered, in eastern Washington State (Richland, WA - desert climate, mostly). I stopped waxing it 20 years ago, but I still wash it once or twice a year. It looks good, and would likely look very good if it was polished and waxed. Cobra did not paint the aluminum sheet used on the top, but purchased it already painted.
>
> It is, apparently, a very high quality, durable paint. There's never been a need to repair or repaint the top, and I would get a metal one again. My choice might be different if I lived in a humid climate.

Eric - the material Spindelberger is using is not painted. It is powder-coated which is baked on, resulting in some of the most durable coatings around.

Uli
'AS'

[Eric Greenwell]

I think you are probably right, but it is confusing the website shows this: "...[the cover is] a monocoque of powder-coated, painted aluminum sheet which is riveted and bonded water-tight.

[Mark628CA]

Back when I was building glider trailers, I used a commercially available aluminum that has a baked-on enamel finish. This stuff has been around for decades. It's used on just about every trailer you see, and it's very durable. Cobra uses similar aluminum with the same sort of coating.

I have seen trailers with a bare aluminum surface right next to a white painted trailer, and the surface temperature in bright sunlight is amazing. You can put your hand on the white trailer with no problem, but the aluminum surface can be hot enough to raise blisters. Same thing on the inside.