Ted Frater wrote:
john wrote:
David Billington wrote:
Ed Huntress wrote:
"David Billington" wrote in
message ...
Ed Huntress wrote:
"Jman" wrote in message
ups.com...
I think I'd rather take the train or bus thanks.......
http://seattletimes.nwsource.com/htm...boeing111.html
http://findarticles.com/p/articles/m..._n8765992/pg_4
I wrote articles almost identical to those 25 years ago. IIRC, the
L-1011 had a carbon-fiber tailfin, as well. And the other story is
the same old, same old for the high-performance composites
business. Very little appears to have changed.
A lot of people don't realize how much epoxy is used throughout the
structure of an airliner. They probably don't want to know. d8-)
However, they also don't know how much fatigue becomes a problem in
all-aluminum aircraft that were designed over the last few decades.
DC3's are still flying because the engineers didn't know what a
reasonable safety margin was. Now they know, and the life of those
planes is finite.
--
Ed Huntress
I was told by late father, who was in the aerospace industry in the
UK and later US as a stress analyst, maybe 25 years ago that one of
the reasons the DC3 kept flying because you could still get
fuselages and wings. When the life of the wings was up you bought
new ones and the same with the fuselage. I expect like many planes
the airframe life is also re-evaluated after actual service
conditions have been experienced and extended or otherwise revised.
Parts for the DC3/ C47 were easy to come by and most of the parts were
stock items. Since the military had over 10,000 C-47s there were plenty
of spare parts available. The DC3 itself was a very simple aircraft,
not like todays flying electronic boxes. There were many variations
depending on how the airline ordered the plane. The Pan Am ones had the
biggest fuel tanks. You would almost never find any major structural
cracks in the wings like you do with later jet aircraft. If you ever
check an AD (sirworthness directive) list for a 747 you would probably
not fly in one. There is a number of them that list cracks in the main
spars of the wing and not to let them get bigger than a certain number
of inches.
I think that's true, but I flew in DC3's in Canada's Northwest
Territories that still had fabric-covered control surfaces. Those
were *old* DC3's, and it was only 20 years ago that I flew in them.
If fabric covered what was the structure of the control surfaces made
of?. I don't know much about wood structures so don't know if they
suffer from fatigue.
The frame of the control surface was all metal.
They just stood up a lot longer. They also had severely reduced load
capacities because of the overbuilding.
In the science museum in London there is a section of a 747 fuselage.
It's quite surprising how thin the outer shell is, looks to be about
2.5mm from memory. Not that I have a problem with that as with a
background in engineering I know some damn good people design these
things and the 747 is a strong aircraft judging from the bits that has
fallen off them and they still kept flying.\
The 747 was a well designed aircraft. It had triple redundant systems
on all critical systems. The one engineer that I knew that was heavily
involved in the design of that plane told me that they estimated a
mechanical failure rate leading to a crash worked out to 1.3 aircraft
in 20 years. The plane has a rate better than that, The crash of the
one in Japan was due to improper maintenace. The others were from pilot
errors or bombs and rockets.
There are still plenty of DC-3 flying, a lot of them are used in the
Bahamas, West Indies and south florida. There was one that had been
going over our place late in the evening, sounded like it had R1820
Wright engines on it, 9 cylinders with 200 cubic inch each you can tell
the difference.
John
Seems like a lot of very interesting reminising going on!!
hope you dont mind me adding a bit.
I was lucky to get my emgineering training on Sunderland Flying boats
and then converted to Shackleton 1 and 2. at RAF kinloss.
A little while ago!.
However its all been so worth while, when hang gliding started in
1976 here in the UK, it was just what I wanted to do.
Finished up representing the BHGA at the CAA in London on the air
management group.
Met some very good people.
Now we have some 800 yds away from here a microlite field.
there they have the 3 axis under 500kgs fixed wing 2 seaters. they turn
finals over the house.
Now they have all steel tube welded fuselages with ali main spars inthe
wings with wooden ribs and fabric cover on all surfaces.
One gronund looped on take off recently and the tubes bent in all sorts
of places but none of the welds let go.
Definately the CAA dont allow home welding.!!
Ed, do you know the book by Ernest Gahn Fate is the Hunter? surely you must?
Also you have a plaque of mine from some time ago. Hope all is well
with you.
Ted Frater Dorset UK.
Still have all my hardware and kit.
.
Ever work on a Pembroke (sp)? I was working on one when I hit the
little lever on the yoke. It sounded like a tractor trailer was
standing next to the aircraft. The lever was for the air brakes. That
plane had air brakes to stop the ground roll.
John