Re: "CF Bike Shatters" - continued

Jambo wrote:
"J. Clarke" <jclarke.usenet@xxxxxxx> wrote in message
news:fb245n0gcm@xxxxxxxxxxxxxxxxxxxx
For a quick test on CF, all you need is a quarter. Tap it with the
edge of the quarter and listen to the sound. If it's sharp then
you
probably don't have a problem, if it's dull then you probably have
a
delam. This is about as effective and reliable as a visual
non-penetrant inspection for cracks in metal

I've never heard nor seen this method adopted by any company,
workshop, airline, and military.

So? Have you comported your life in such a manner that you would
expect to see composite aircraft structures being nondestructively
tested?

You can be sure that any technician
using this method will not be in that job for very long.

Then I guess you better fire the inspectors at Airbus.

You'd best
hope that the next plane you fly with composite structural
components
haven't been checked by someone using your quarter tap method.

Why would one want to fly in an airplane that had not been properly
inspected?

and is pretty much the
method that is used in the aircraft industry for inspection during
production and rework of composite parts.

Can you reference this process in any manual or procedure by any
aircraft company?

Here's one from 2006 from the NTSB.
http://www.ntsb.gov/Recs/letters/2006/A06_27_28.pdf

One from Aircraft Maintenance Technology
http://www.amtonline.com/publication/article.jsp?pubId=1&id=2521

One from Boeing presented at Texas A&M (scroll down to near the end)
http://otrc.tamu.edu/Pages/Established%20NDE%20Technology.pdf.

Here's an expensive tool from Mitsui that automates the process.
http://www.wp632.com/

If you google "composite tap test" you'll find many other descriptions
of the process, patents for devices based on it, papers concerning its
application, etc.

It's a very well known process in the industry, it was taught to me in
1979 when I was first hired as an engineer at United Technologies
Hamilton Standard and I've seen it used by engineers and technicians
from Lockheed, Boeing, DeHavilland, Bell, the Navy, and the Air Force
that I can remember. I don't have the numbers for the manual but
you'll find it described either directly or by reference in the
overhaul manual for the Hamilton Standard 54460 and 24PF propeller
blades, spinners, and afterbodies, and in the overhaul manual for the
54H60 spinner and afterbody. It's also described in Burt Rutan's
plans for the VarieEze and LongEze aircraft.

You can find specially made
hammers but a quarter works fine for a quick check.

Metal components crack, but at least you have a chance of
inspecting
for cracks.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)


.

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