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Fabric Cover Weight

Dig:

I don't know the answer to that, but my mechanic, who's covering my Cub says that the new fabric, AirTech, will weigh 75 lbs. less than the old Stits did. I sure hope he's right. I'll know in about a month.

murph
 
Murph,
According to the Polyfiber book, a J-3 that uses the heavyweight fabric and the prescribed coatings has 43# of fabric and paint on it. 33# for standard weight fabric. 75# for grade A cotton and dope per factory original. If that's true, your mechanic is pretty optimistic.
SB
 
I'm in the process of recovering a couple of PA-11 wings. I've removed the fabric, was Grade A, and although I haven't weighed them, I find it hard to believe they would weigh 75lbs.

Brian
 
Murph, and Brian,

Would you be so generous to weigh your wings, Left and right, (if I remember correctly, Murph, you installed one Atlee tank?)
Weight before silver, after silver, and after paint/color?

Also if you could document what mods were installed with recover process, IE: spar doubler at strut, tie down, heavy long leading edge etc. also the type of material, process and number of coats?

Much appreciated,

Tim
 
Tim:

I'll see what I can do. Since I'm hiring my work done, it's hard to get my guys to break their stride when they're working. I don't think my guy has a good scale yet to weigh the stuff. I do know that the Atlee tank adds 6 lbs. vs standard, plus we added the stainless tiedowns. Those probably add about .5 lbs. each.

murph
 
Try if you can? He should weigh it when he's done anyway so to provide you with an 'accurate' WB sheet?? Bathroom scales work fine (mine lies for me every time I get on it!)

Tim
 
Tim, I don't have access to scales, or I'd do it. We'll probably rent some electronic scales when done to compute the W&B. Sorry
Brian
 
We asked our selves this same question and we started out and weighed our cub wing bare and it weighed 69 lbs. for the panel pre-cover no wing tank. Don't remember what it weighed after. We weighed a 7GCBC wing panel after each step and calculated that Superflite System II added 75 pounds to that aircraft. Probably the lightest will be a dope finish (utility finish with minimum coats). Just how much I don't know for sure but would have to guess at 40-50 pound range.

Matt
 
This is from the AirTech Coatings website. Three wet crosscoats of primer/filler and two coats of color (five coats total) are the minimum to meet the STC.


Coating Weight Comparison

A frequently asked question from customers is how much does the coating process weigh. In truth all fabric covering processes weigh less than metal or composite and in fact this is one of the main reasons fabric was chosen in those days when horsepower was not available. AIR TECH weighs less than any other coating system:
COATING WEIGHT COMPARISON
Aprox. coating weight including fabric in oz/sq.ft.
Fabric Weight Air Tech Stits Stits Dope
5 coats - 7 coats - 12 coats - 20 coats
1.8 --- 0.7 --- 0.9 --- 1.4 --- 1.6
2.7 --- 0.8 --- 1.0 --- 1.5 --- 1.7
3.7 --- 0.9 --- 1.1 --- 1.6 --- 1.8


Aircraft

J-3 Cub
750 sq. ft.
2.7 oz fabric --- 37 lbs. --- 46 lbs. --- 69 lbs. --- 78 lbs.

The Air Tech system will weigh about 1/2 that of Dope!!!


Air-Tech Coatings Inc. 1 Paradise Park Road Jacksonville, AR 72076 PH 501-985-1359 FAX 501-985-1359 E-Mail
 
Polyurathane

Will the Air Tech "all" polyurathane system last 25 years and still be serviceable like my Ceconite and dope system did? Has it even been out 25 years? No...Also what do you do when a polyurathane system gets cracks in it????....nothing, you're absolutely screwed, get out the utility knife and cut it all off and start over. Crash
 
Murph, Bring your plane over when done and I will weigh it on the same scales as I did before your rebuild. Thay are digital and were calibrated recently. Also if they saved the old fabric we can weigh it. I would guess it weighs at the most 75 lb.
 
Steve, If I come down to TX can we weigh my Freightliner? I will remove the tire chains and the chain binders, spare tire and remove all the items from the sleeper cab! that should lighten it by 1500lbs or so?

Tim

PS: Crash, Do you know of anyone using the Airtech system in Alaska?
 
You bet Tim. I weighed a SC recently and forgot to take the stuff out of the storage box under the seat. It weighed 45 lbs. Who woulda thought. Bring her down but wait till the weather isn't like what you are used to (rain).
 
Thanks, Steve. I might just do that if Harold doen't come up with some scales.

murph
 
hello,

i have airtech fabric on my 47' pa-12. it was put on by the factory. please feel free to call me if you have any questions. 612-710-1137
thanks
tim peterson
 
Fabric

Hello: That's funny, you say your 1947 PA-12 has a factory Air Tech cover job. Did you have Piper recover your PA-12 around 1993 or '94? All Piper rag and tube planes left the factory with grade A cotton or linen until the mid 1960's. The Piper factory started using Ceconite fabric and dope on the PA-18 (last of the rag and tube production) around 1968. It has been said that the last two years of production (1993 & '94) Piper used the Air Tech system on the PA-18. Crash
 
I think Turbo means Air-Tec put the fabric on his 12. They used to use a 12 in their display area at Sun & Fun and at OSH. It has a real fancy paint job.
 
Went to the IA seminar this past Sat. and sat in on a couple of presentations from Jim Miller, who is a Poly-Fiber dealer and he gave some interesting information on the different systems in use today. There is a guy from St.Louis area that did his Doctoral Thesis on the different covering systems and said that the dope (Poly-Fiber/Randolph) added about 45-50 lbs, Air-Tec 75 lbs. and Superflite 105 lbs. He also said that after covering and completing a pull test that the polyurathane systems had the strongest pull test. Retest after one year of aging and the dope systems pulled the most. He said the cause was from the dope systems using Aluminum powder as the UV protection where as the polyurathane only used what was in the paint. I'm going to try to contact Jim and see if I can get a copy of the thesis.

Matt
 
According to 43.13 pull testing fabric to determine airworthyness (?) requires the removal of all coatings.
 
Fabric Weight

I have some rather unscientific information on fabric weight.

Was in the shop this afternoon where they had just pulled the cover off one of the wings that was damaged in the big windstorm. It was a standard PA-18 wing with ceconite with dope and had the rib stitching still attached.

It was 10 pounds plus or minus a 1/2 pound.

Wish I'd thought to do the same thing with my wings, since one of them was stits and the other ceconite, would have been interesting.
 
During my wing rebuild we pulled the cover off of one wing and weighed it. It was Stits polyfiber with a relatively heavy coat of Aerothane (no fabric weave showing). The entire cover weighed 9.5 lbs. I was surprised, I expected it to weigh more.
 
I always thought the fabric weight was in oz. per sq. yard, not sq. foot. Put a square foot of 2.6 Stits on my handy dandy electronic postal scale and it bounced between .3 and.2 oz. If you divide 2.6 with 9 (sq. ft in sq.yd) it comes out to .28888 oz. per sq.ft. A cubs 750 sq.ft x.28 =210 oz. divided by16=13.125 lbs of fabric on the wings. The rest of the weight is the "dried" coating film. The total fabric weight after the solvents, ect. dry out of the new coatings isn,t anywhere near the weights as listed. I am sure they list the weight of the "wet" material they use for their coatings. Dried stuff tends to be lighter than wet stuff. That is why fabric removed from a wing tends to weigh around 10 lbs.
Steve
 
Doubt if there would be much. The more coats will increase the total film thickness, but enough to be a major consideration? The one thing to remember, dope products are a cohesion system as to a enamel being a adheshion system. Properly applied dope systems "melt" together to form one film, so the more coats the thicker the film. Enamels,polyureathanes, etc. adhure to the surface and is actually a seperate film from the base coatings. Then too, how much of each coat do you sand off to get that smoooth finish.
Steve
 
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