Rib stitching vs glueing

wrote in message
ups.com...

That sounds pretty much like what happened to Steve Wittman.
He put off fixing the problem until after he got to Oshkosh.

--

FF

Ok, I'm curious, since I haddn't heard this before, and it doesn't seem
to be part of the report (ATL95FA092) in the accident database.

That's really not too surprising, since the folks I knew who rushed off
to take part in the investigation regarded Steve Wittman as roughly
equal to Jesus of Nazareth...

At least hypothetically, delamination could have been detected in the
same manner on the O&O Special as on a composite aircraft--by
taping with a coin, or even a fingernail. However, Mr. Wittman was
not tall enough to do so on a plane larger than a Tailwind, and this
would appear far beyond the scope of a pre-flight inspection unless
one had some cause for suspicion; whether visual, hearsay, or some
anomoly on a previous flight.

Sooooo, tell us more...

Peter

Peter Dohm wrote:
wrote in message
ups.com...

That sounds pretty much like what happened to Steve Wittman.
He put off fixing the problem until after he got to Oshkosh.

--

FF

Ok, I'm curious, since I haddn't heard this before, and it doesn't seem
to be part of the report (ATL95FA092) in the accident database.

...

At least hypothetically, delamination could have been detected in the
same manner on the O&O Special as on a composite aircraft--by
taping with a coin, or even a fingernail. However, Mr. Wittman was
not tall enough to do so on a plane larger than a Tailwind, and this
would appear far beyond the scope of a pre-flight inspection unless
one had some cause for suspicion; whether visual, hearsay, or some
anomoly on a previous flight.

Sooooo, tell us more...


I read, but do not recall where, perhaps you should DAGS in this
newsgroup, that someone who helped Mr Wittman prepare the
O & O for that last flight noticed a problem and tested the
fabric by pulling on it with a suction cup. Even though some
pulled loose, Mr Wittman did not think it was that serious
and the helper deferred to Mr Wittman in the matter.

That is not reflected in the NTSB report, but it may be that one
person helped him prepare the plane and a different person helped
with the pre-flight inspection per se.

--

FF

Ed Sullivan (a really big show tonight) wrote:

...

The technique Tony Bingelis was refering to in his book was covering a
plywood covered aircraft in model airplane weight fiberglas. I used
the same material for the last layer on my wing and empennage tips as
well as the leading edge. Makes a real smooth finish without excess
filling.


Adding a layer of fiberglass must greatly inprove the stength,
durability, impact reisstance and water resistance, that is why
it's freqently done on plywood canoes, kayaks and small boats,
as well a producing a smooth finish.

If a smooth finish over wood is the only goal, then surely covering
with fiberglass is a lot of unecessary work. Fine Furniture makers
have been starting with rough wood and producing a very smooth
surface for a couple of hundred years. Grain filler and a cabinet
scraper (NOT a paint scraper) should do the trick for the airplane
builder.

--

FF

wrote in message
oups.com...

Peter Dohm wrote:
wrote in message
ups.com...

That sounds pretty much like what happened to Steve Wittman.
He put off fixing the problem until after he got to Oshkosh.

--

FF

Ok, I'm curious, since I haddn't heard this before, and it doesn't seem
to be part of the report (ATL95FA092) in the accident database.

...

At least hypothetically, delamination could have been detected in the
same manner on the O&O Special as on a composite aircraft--by
taping with a coin, or even a fingernail. However, Mr. Wittman was
not tall enough to do so on a plane larger than a Tailwind, and this
would appear far beyond the scope of a pre-flight inspection unless
one had some cause for suspicion; whether visual, hearsay, or some
anomoly on a previous flight.

Sooooo, tell us more...


I read, but do not recall where, perhaps you should DAGS in this
newsgroup, that someone who helped Mr Wittman prepare the
O & O for that last flight noticed a problem and tested the
fabric by pulling on it with a suction cup. Even though some
pulled loose, Mr Wittman did not think it was that serious
and the helper deferred to Mr Wittman in the matter.

That is not reflected in the NTSB report, but it may be that one
person helped him prepare the plane and a different person helped
with the pre-flight inspection per se.

--

FF

Thanks, FF, that explains it. I don't personally know anyone who
wouldn't have deferred to Mr. Wittman on the matter He was the
designer, builder, and pilot of the plane and also highly regarded as
a guru in that type of construction.

It's interesting in that it provides a "quick and dirty" method of
non-destructive testing, and also a reminder to *really* understand
a manufacturer's recomendations for using or installing a product.

It was certainly unfortunate, but not nearly so bad as the prospect
of pining away in nursing home a few years later.

Peter

p.s.: Since I'm confident that I have a few years left; I'm gratefull
for one more tool (the suction cup) to check for latent defects.

Peter Dohm wrote:

...


It's interesting in that it provides a "quick and dirty" method of
non-destructive testing, and also a reminder to *really* understand
a manufacturer's recomendations for using or installing a product.

I dimly recall that there was a way to measure how much force
it took to pull away the cloth, something more elaborate than
'feels like' but it has been a couple of years since I read that.


It was certainly unfortunate, but not nearly so bad as the prospect
of pining away in nursing home a few years later.


He wasn't flying alone.

wrote in message
oups.com...

Peter Dohm wrote:

...


It's interesting in that it provides a "quick and dirty" method of
non-destructive testing, and also a reminder to *really* understand
a manufacturer's recomendations for using or installing a product.

I dimly recall that there was a way to measure how much force
it took to pull away the cloth, something more elaborate than
'feels like' but it has been a couple of years since I read that.

Possibly a "fish scale" and some calibration data from Stits or a
similar source. In the event that I visit Sun n Fun this year, there
may be a source of further information. I have no present contact
with fabric and glue, but will try to alert chapter members who do.

It was certainly unfortunate, but not nearly so bad as the prospect
of pining away in nursing home a few years later.


He wasn't flying alone.

Quite true.

An now a few more of us know one more thing to watch for.

The point that I did not state, and on which I'll try not to start a
rant, is that I little bit of fatalism is appropriate in aviation, driving,
bridge construction, warfare, mining, and nearly everything else
that we do. There are no guarantees, so you have to trust what
you believe is greater knowledge and experience. In this instance;
Mr. Wittman, Mrs. Wittman, and the "helper" all believed that Mr.
Wittman had the greater knowledge and experience and, in this
particular matter, he did not. As we say: "Stuff happens."

Peter

On 14 Oct 2005 17:34:46 -0700, wrote:

I vaguely remember reading in the FAA/NTSB archive about such an
incident. It was a while ago, so I may be a bit off. What I remember
was that the pilot was killed on impact and apparently he was aware of
some minor seperation and continued to fly the aircraft until it failed
catastrophically. Might have been another bird, but I think it was a
celebrity. I'm not 100% sure though. You might try searching the
accident database for the celebrity if you haven't already.


That sounds pretty much like what happened to Steve Wittman.
He put off fixing the problem until after he got to Oshkosh.

I spoke with a pilot recently who is from Florida. Somehow Wittman's
accident came up and this pilot opined that while it's true that the
fabric appears to have delaminated from the wing thus causing the
catastrophic flutter that seperated the wing from the fuselage, he
thinks the Air Force had a hand in the accident. He, and some others
from his area, feel that wake turbulence may have jolted the wing into
flutter. There were military aircraft flying low level practice
missions in the area where he went down, according to this guy.

He didn't think the fabric would have delaminated without some kind of
jolt.

I don't know, it was an old airplane that had been sitting around for
a long time and it was a relatively fast cruiser. It may have been
possible for the fabric to rip loose without any help from close
passing B1's.

Corky Scott

wrote:
On 14 Oct 2005 17:34:46 -0700, wrote:

I vaguely remember reading in the FAA/NTSB archive about such an
incident. It was a while ago, so I may be a bit off. What I remember
was that the pilot was killed on impact and apparently he was aware of
some minor seperation and continued to fly the aircraft until it failed
catastrophically. Might have been another bird, but I think it was a
celebrity. I'm not 100% sure though. You might try searching the
accident database for the celebrity if you haven't already.


That sounds pretty much like what happened to Steve Wittman.
He put off fixing the problem until after he got to Oshkosh.

I spoke with a pilot recently who is from Florida. Somehow Wittman's
accident came up and this pilot opined that while it's true that the
fabric appears to have delaminated from the wing thus causing the
catastrophic flutter that seperated the wing from the fuselage, he
thinks the Air Force had a hand in the accident. He, and some others
from his area, feel that wake turbulence may have jolted the wing into
flutter. There were military aircraft flying low level practice
missions in the area where he went down, according to this guy.

Prior to the release of the FAA report there was speculation about
that in the rec.aviation newsgroups:

http://groups.google.com/group/rec.a...e=source&hl=en

And that an improper bolt may have been used in the horizontal
stabilizer:

http://groups.google.com/group/rec.a...e=source&hl=en

The FAA accident report (link appears earlier in this thread) refers
to both issues. They ruled out B1 turbulence and do not appear to
have drawn any conclusions as to the latter.


He didn't think the fabric would have delaminated without some kind of
jolt.

Respecfully, did he personally see the O & O special, ever?


I don't know, it was an old airplane that had been sitting around for
a long time and it was a relatively fast cruiser. It may have been
possible for the fabric to rip loose without any help from close
passing B1's.


--

FF

Steve's plane was less than 10 years old I believe at the time of the
accident. Not very old as plane go.


wrote in message
...
On 14 Oct 2005 17:34:46 -0700, wrote:

I vaguely remember reading in the FAA/NTSB archive about such an
incident. It was a while ago, so I may be a bit off. What I remember
was that the pilot was killed on impact and apparently he was aware of
some minor seperation and continued to fly the aircraft until it failed
catastrophically. Might have been another bird, but I think it was a
celebrity. I'm not 100% sure though. You might try searching the
accident database for the celebrity if you haven't already.


That sounds pretty much like what happened to Steve Wittman.
He put off fixing the problem until after he got to Oshkosh.

I spoke with a pilot recently who is from Florida. Somehow Wittman's
accident came up and this pilot opined that while it's true that the
fabric appears to have delaminated from the wing thus causing the
catastrophic flutter that seperated the wing from the fuselage, he
thinks the Air Force had a hand in the accident. He, and some others
from his area, feel that wake turbulence may have jolted the wing into
flutter. There were military aircraft flying low level practice
missions in the area where he went down, according to this guy.

He didn't think the fabric would have delaminated without some kind of
jolt.

I don't know, it was an old airplane that had been sitting around for
a long time and it was a relatively fast cruiser. It may have been
possible for the fabric to rip loose without any help from close
passing B1's.

Corky Scott

On 14 Oct 2005 09:56:25 -0700, wrote:


In his blue book (Sportplane Builder) he has a Chapter near the
end on Dacron, but Chapter 5 is 'Fiberglass Tips' and has a section
'Fiberglass Your Bird'. This discusses using lightweight
fiberglass cloth and resin to cover a plywood fuselage, similar
to light boat construction. (BTW, there is a boatbuilding
technique called 'stich and glue' which looks to be adaptable
to stressed skin construction.)

stitch and glue is used on the mirror dinghy. it works but I'd stick
with proven aircraft techniques because they build lighter.


But I don't think he suggests fiberglass cloth and resin over
ribs with nothing else underneath. ISTM that the cloth would
sag between the ribs and unlike the dope in the razorback system,
the curing resin would not draw it tight, unless you found
a resin that would shrink. Hmm, doesn't some poylester resin
shrink when it cures?

look in the eaa magazine archives for articles describing the building
of a one off homebuilt called "ol ironsides" that describes a sound
method of making fibreglass covering for a fuselage that is over a
truss wooden fuselage. afaik ol ironsides was basically a wooden
single seat Tailwind.

Stealth Pilot
ps
one of the advantages of definitive works like Tony's books is that
they rapidly bring everyone up to the state of the art.
the disadvantage only becomes evident after some time.
nobody moves past that standard for quite some time.