Shrink Wrap Wings !

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proppastie

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Will you rib stitch, pop-rivet or glue to the structure? I believe it is important for "pillowing" although I am not a fabric expert.
 

proppastie

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please continue to up-date us, I know I would be very interested in how this holds up. Will you keep it inside a hanger or storage unit?
 

airplaneAddict

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So far I keep it outside the shop to work on it.

During winter it will be stored in my storage unit with it's wings folded back.

I have a week of clean up items before trying to start the Rotax 503.

Then I'll taxi and do a few hops to get the feel of it.

After that I may have to takeoff, keeping a landing spot within eyesite and gliding distance.

My wife want's me to wait until next spring to fly it, so she can increase my life insurance :-}
 

proppastie

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So far I keep it outside the shop to work on it.

During winter it will be stored in my storage unit with it's wings folded back.
Some of the technical specifications said 1 year UV protection or 3 year. I am not sure what that means as regards a steady loss of strength or not. Might want to keep it inside when not flying after you finish. Might be instructive to build a test frame with scraps, and get a fabric punch tester to test for any loss of strength if you do decide to keep it outside.
 

airplaneAddict

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I used a metal ruler to do a punch test...really strong stuff...it's 3 times as thick as the models I cover...I can't keep it inside, because I don't want to fold the wings back very often...not to worry, as a newbie pilot it won't last long most likely :-} UV is the least of my worries.
 

proppastie

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I guess the question I have is how will you know when it has deteriorated "too much" It is guaranteed to deteriorate from UV. Weather the wax, paint or whatever works is the same question, how will you test it/evaluate it. If the top of the wing, or control surface fails you could get hurt, and that is what will fail first because it is exposed to the sun the most. That it is a cheap easy covering is great, one answer could be recover every year if it is really cheap and easy,....However that might not be good enough even. Please think about some sort of method to know how your fabric is holding up. There are standards for sail cloth or fabric that was original for your aircraft. A call to the factory or compare to other similar craft could get minimum strength standards as a comparison.

You also could make wing tail covers when not flying. Let us know how is coming.
 
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airplaneAddict

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Thanks for your concern.

I can poke it with my finger and it goes through I won't fly.

Honestly, the plane may not last that long, as I'm a new pilot.
 

proppastie

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I have done a little research, comparing 1 brand of shrink wrap with oratex for use on a mini max or US ultralight. The shrink wrap, like oratex, would save time and weight over traditional coverings that need filling and painting.

Shrink Wrap Containment for Buildings and Construction - Pro-tect Plastic & Supply, Inc.
priced smallest rolls available

Construction Industrial Shrink Wrap
flame retardant, uv protection
12 mil .065lb/sf $.21/sf
10.5mil .056lb/sf $.16/sf
9mil .049lb/sf $.14/sf

boat wrap - white and blue available
7mil .035lb/sf $.084/sf 5.04oz/yd

2"x60yds 9.5 mil seam tape $8.50 white 4" & 6" tape available

I could not find the similar breaking and tear strength specs for the wrap. I am assuming it is less than any common cloth

----------------------------------------------------------------
TECHNICAL SPECIFICATIONS / DOWNLOAD SOLARIG™ 172 DATASHEET
Parameter Units Specification
Cloth Weight oz/sqft 5.1 ± 5%
Thickness mil 8±1
Breaking Strength lb/inch ≥84
Elongation at Break % ≥20
Tear Strength lb ≥33
Light Transmission % 88%
Diffused Light % 60% ± 5%
Direct Light % 28% ± 5%
Thermicity (Lower is better) 20
UV stability Years of warranty 6 years

-----------------------------------------------------------------
Oratex
6000 .31 - .35lb/sf about $91/yd 2013 72.22/yd or $8.03/sf including tape
Tensile strength lengthwise: Min. 1300 – 1600 N/50 mm
Tensile strength crosswise: Min. 1100 – 1400 N/50 mm
Breaking extension lengthwise: 12 – 20%
Breaking extension crosswise: 12 – 20%
Tear propagation load lengthwise: 26 – 32 N
Tear propagation load crosswise: 28 – 34 N

600 .20 - .27lb/sf estimate of $50/yd or $5.56/sf including tape
Tensile strength lengthwise: 750 – 1050 N/50 mm
Tensile strength crosswise: 650 – 950 N/50 mm
Breaking extension lengthwise: 10 – 18%
Breaking extension crosswise: 11 – 20%
Tear propagation load lengthwise: 18 – 24 N
Tear propagation load crosswise: 16 – 22 N

commonly used fabrics, fillers, and paints systems can be heavier by 20lbs or more than oratex according to this poster on Wings Forum • View topic - Oratex:
Re: Oratex
Postby cmcgeary » Wed May 01, 2013 7:45 am

I've also been researching this stuff. It comes in 2 weights (600UL and 6000). Still trying to do a direct strength comparison between it and convention fabrics like Ceconite. Given 90 sq yards of material, plus trim tape costs, etc., I estimate ~$4500 to cover in 600UL and ~$6500 to cover in 6000. Folks on the Supercub site are saying to figure on $5000 in materials to cover a Supercub in Polyfiber.

Finding accurate material weights for conventional fabrics was difficult, but Brian over at Supercub.org did some painting and weighing. According to him, 3.16 oz Polyfiber with PolyTone & PolySpray weighs 6.3 oz/sq yard covered for UV only. Painted white, you're up to 7.6 oz/sq yard. Someone else weighed the same fabric with Stewart Systems Grey at 6.4 oz/sq yard. 600UL weighs between 3 and 3.5 oz/sq yard depending on color. 6000 weighs 4.2 to 4.6 oz/sq yard. So, if you cover the SuperSTOL like the Sun'n'Fun bird (2/3 UV silver, 1/3 Red & black paint, all 2.7 oz Superflite), you end up with about 35 lb of covering. Cover the bird in Oratex 6000, you end up at 26 lb for the heaviest color. If you cover all in the heaviest Oratex 600UL, you end up at 20 lb.

Since my Dad and I want to build the SuperSTOL we have on order in my basement, and we don't want to gas ourselves, our wives or the cat, the Oratex sounds great! It's a 35 minute drive to the airport (my alternate build site). I'll save the difference in cost in gas alone. Now, I just have to figure out how much of the plane we can safely cover in 600UL.....





Yes, the more you spend, the better material you get.
for my slow little mini-max, I will use ~38yds fabric or wrap.
I estimate $2500 to cover it in oratex 600 in 2016.
the boat wrap only comes in large rolls, 1400sf for the smallest. Thats 155yds. But it is only $118 plus shipping for a 14'x100' roll (no mid-wing seams). Add 2 rolls of seam tape and their spray glue to pre-tape the ribs and edges. I'm at about $150+ and 12lbs. a little heavier than Oratex at about 10lb, and not nearly as durable, nor colorful. a Polyfiber with PolyTone & PolySpray would be just over 18lbs if you know what you are doing. Even heavier with latex paint. I could sell the remaining wrap or keep it for recovering. I would prefer oratex, but for this inexpensive build, I just can't justify the extra cost.
Since it has been used on an ultralight before with good results, I would try it. I may have to recover in a few years worst case. but at that price I am still ahead.
I wouldn't use it on anything that flys over ~90mph or weighs more than 500 or so pounds until more test have been made. I think a good test would be to make a frame, cover and test it. In the winter i can get up to 75mph winds near the foothills west of denver, that would be a good test also. I have a door frame that would be a perfect test bed. I have some left over polyfiber to test with also. I will have a closer look at their glue before using it, but it sounds like it is formulated for use with this wrap.
I guess I have talked my self into at least testing the wrap.
I found this as to strength. see attachment

Edit: I calculated the PSI of Oratex 600 (650 N/50mm) to come out to 15,745 PSI vs 3000 PSI for the shrink wrap.

330 N/in. = 74 lb/in...... .0047 in thick = 15745 lb/sq in

That is not to say the shrink wrap is not strong enough for UL aircraft, but it is a data point for consideration.
 

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