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maule fabric testor

It would have to be calibrated and certified at least once to use it on certified aircraft to test fabric strength.
 
There is no FAA approved punch test for fabric. The Maule or Seabooth punch testers are not technically an approved method of testing fabric they are only considered a generally accepted method of testing. There is not speck for punch testing only pull testing. To properly test fabric you need to remove a strip from the sun exposed section of the aircraft, remove the finish from the fabric, then pull test it. 43.13 has the info on testing fabric. General rule of thumb is that if you cant put your thumb through the fabric it's airworthy :)

Jason
 
jgerard said:
... General rule of thumb is that if you cant put your thumb through the fabric it's airworthy :)

Jason
Click to expand...

yeah thats always been a conundrum to me, where FAA want new types of fabric to be within some percent of it own new strength,(which is MUCH stronger still than the original cotton new!)... I would think as long as its stronger than the original cotton in it's lowest acceptable condition, that the new stuff is ok still.....
 
I can!t believe that its that complicated to build one, it seems that whats involved is two aluminum tube that would slide over one another with a small stud on one end and a spring with the right tension in compression to measure 60 lbs in compression. certainly not $200 plus of materils.
 
Nope. not complicated to build one, but to be approved for certified use, it has to go through rigorous (ridiculous?) testing several (expensive) times. Since no one wants to take any responsibility for anything, it gets approved subject to the next dep't (guy) approving it... & so on.... ad. nauseum. By the time you get your "approval" the cost of approving it has gone north of $9K, so your customers need to pay you back. This goes for every part on a certified airplane.
Am I a bit biased? heh...heh
 
AC 43.13, Chapter 2, Section 3 paragraph 2-34.
Punch type testers are not approved by the faa, but (are used at the discretion of the mechanic.)
(If the fabric test in the lower breaking strength range with the mechanical punch tester----) then you use the strip test.
The way I read it, It's ok to use it if I want to. (My discretion.) It's also ok to use on dacron fabric. I think they exclude fiberglas covering.
 
Steve Pierce said:
Has anyone found Dacron fabric bad with a Maule fabric tester?
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Cole Palen built a replica 1910 Hanriot wing warping monoplane in the mid 1970 and covered it with dacron, he used one coat of clear dope only to protect it from the oil that spewed out of the engine because he had to keep it lite. The covering on the wings got changed in the early 1990s because it was so oil soaked but they left the tail covering alone. We took that airplane apart and sent it to Australia in 2003 and the tail fabric was getting bad, you couldn't poke your finger thru it but a blunt pencile would go right thru. We flew it 10 times down there but changed the tail fabric when it got back home. This fabric sat outside 8hrs every Sat and Sun from June to Mid October on the showline in the sun for over 25 years WITHOUT any UV protection.

Glenn
 
Steve Pierce said:
Has anyone found Dacron fabric bad with a Maule fabric tester?
Click to expand...

I expect same as you I found 40 year old ceconite that I couldn't punch a hole in or tear in half by hand. But the paint was dried out and peeling, the inspection rings(no doilies) were falling off, and the tapes were lifting. The fabric was outlasting the glue. But there was the 7ACA Champ at Patrol Guy's field that still had it's original fabric and my mechanic mentor put his thumb through the stabilizer without trying. At the time I think the fabric was 35 years old +or-. jrh
 
I just wonder if anyone has hada Dacron covered airplane with UV block fail a punch test? I have found cotton that failed the punch test but don't even bother punching Dacron. I do apply silver to bare fabric when I find it.
 
I think if you feel the need to punch test the fabric it's probably time to replace it. Also it's been proven that fabric punches higher with a finish on it than fabric that's had the finish removed. Instead of building a tester how about you borrow one. By the way if a maule tester has been used to punch test struts it screws up the calibration on fabric. I have seen fabric that punches ok but when it's tested per the regs it fails. Ill mail you my tester if you promise to return it. I can't guarantee it's accuracy.

Jason
 
I am with Steve. Dacron without UV protection does die, and it dies quickly outdoors. We have a derelict Champ on the field, and where th silver is peeled off, the fabric disintgrates into white ash with a light finger touch.

The only use for a Maule tester is to fulfill that strut A/D. Opinion.

Another opinion - they ought to quit writing A/D's that specify a proprietary tool.
 
Jerald, I certainly will take you up on your offer to loan the testor to me. Your nice enough to loan I would most certainly return it to you. Address is CS Henderson. 18 Pasture Lane West Lebanon. NH. 03784. Phone No. 603-208-5621.
 
If you can't clean all the dope/finish off the area tested, don't bother. It will read/break lower the stiffer the fabric/ finish. I built a pull tester and cross checked it against the Maule tester under various conditions. Used up a lot of fabric.....
I thought I was impressing my IA, but I wasn't. He said that when it caught a case of fungus, it would go to zero overnight, and your arm would go through it when you pushed on it with your thumb. In the end, he was right. It went from 66lbs/inch (for the last 20 years) to zero (in places) after some wood slivers* from my hanger trusses got into my right wing under the edge of my tank cover. He used to poke my fabric whenever we flew anywhere, and sing me a little song:"This 'ol cotton, it's gonna get rotten"...

*chewed by some critter...
 
Last edited:
F
objobthanks for the reply,The fabric on my bird has been on sines 95 when I finished building it. It looks good and don't want to recover if it doesn't need it.
 
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