WW II aircraft fatigue life

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I helped an owner/ operator maintain a PBY for a few years and it was a corrosion nightmare even though the last operator seemed have maintained well (it was operated in Spain as a fire bomber). Although manufactured way later, some of the east block aircraft I worked on (MiG-15s, L29s, L39s) had little or no corrosion issues on the airframes, the hardware seemed to be more susceptible to corrosion.

Agree with your assessment on fabric and wood. I saw a Pitts basically shrink itself apart when it was brought to SoCal from Washington state.
 
FLYBOYJ said:
I helped an owner/ operator maintain a PBY for a few years and it was a corrosion nightmare even though the last operator seemed have maintained well (it was operated in Spain as a fire bomber).
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PBYs and WWII seaplanes almost deserve a separate discussion as they not only were subjected to salt air, but through leakage and condensation, had it pervade into every internal nook and cranny. Anodizing was largely developed to a fine art by Consolidated to protect their seaplanes, but they still needed constant inspection and treatment.
The Japanese had a remarkable brilliant green lacquer they sprayed on the interior of Naval aircraft, so effective that wrecks show far less corrosion even after decades in jungles. However, it was not as effective on seaplanes, and the last remaining Emily had holes through the skin from salt exposure before being transferred from Norfolk back to Japan ... I believe in the '70s.
Another factor was wartime metallurgy. Effective blockading of Germany and Japan denied the Axis of critical elements like cobalt, chromium, etc. to alloy with their steels and aluminums. NASM's Kyūshū J7W Shinden has only been partially restored as the wing spar has become unstable in the internal structure due to alloying chemistry, and will need an entirely new spar of stable alloys to complete. German jet engines were failing within 25 hours of running due to low strength steels deprived of critical elements.
 
The one I worked on had, in some areas the same corrosion preventative compound used by Boeing. During the time I was working on this PBY, my fulltime job was at a Repair Station where we were doing C checks and avionic mods on 737s. I think the previous owner's intent was to do the whole aircraft.
 
The B-17 was the preferred bomber because it was much easier to fly and could sustain much more damage than the B-24.
 
The reason it took more man-hours (worker-hour as many of the workers were females...) to build a a B-17 in Long Beach was because more rivets were used in the construction of a Douglas built B-17 than a Seattle built one. I was told this piece of information by an old "Rosie the Riveter" who used to work in Douglas's B-17 production line. She came to see "Sentimental Journey" (which was built by Douglas) and immediately recognized that it was a Douglas built B-17. Asked how she knew she replied "by the abundance of rivets". She even showed me the rivets she herself drove. The imbalance in man-hours lasted until the end of 1944 when I guess many experienced Boeing workers were diverted to build B-29s, leaving the B-17 to inexperienced workers.

It is interesting to see that Vega caught up very quickly with Boeing, surpassing everyone with lower man-power per ship than everyone else.
 
Big Jake said:
many experienced Boeing workers were diverted to build B-29s, leaving the B-17 to inexperienced workers.
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Fast forward 45 years later. In 1990 I worked on the B-2 program. Boeing made the outer wing sections as a contractor and supplied Northrop with manpower to assemble the first several units. At the same time Boeing was opening the 767 line. What I discovered is Boeing had an apprentice program where they sent folks from Seattle down to Palmdale to assist on the B-2 final assembly. When these folks got some experience under their belt they went back the Seattle to work on the 767 line. I seen a lot of "hacks" that hung around, some were eventually terminated.
 
Its not Fatigue that is the biggest risk for our irreplaceable warplanes. Its stupid people that don't know that they don't know.

 
thunderbird said:
Its not Fatigue that is the biggest risk for our irreplaceable warplanes. Its stupid people that don't know that they don't know.

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Thunderbird,

I have been watching this story and numerous news streams (including my own in house union) regarding causes and or factors. It is a terrible tragedy. However let the investigators do their work and unravel this event before coming to a conclusion. It very well may be exactly what it looks like (loss of situationAl awarenes) SA, but what contributed to it will need to be assessed (and may lay additional blame outside the P63 driver).

And we see people everyday in traffic who absolutely don't know what they don't know (I have a 16 y/o son who is getting close to obtaining his DL) and we have that conversation every single time he is in the car.

He also has to obtain enough situational awareness as well as physical skill before his fighter pilot father will consider him ready to go solo (get his DL).

Cheers,
Biff
 
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Totally agree Biff. When I was active flying, we were constantly told "never turn on the inside of an aircraft" the wing always blocks the aircraft you are turning inside of.
Personally, I think that something happened with the p-63 and the pilot got distracted, hence he was flying faster and inside aircraft that should have been on his inside. It will be interesting to see the final report.
 
As I understand it he was also #3 in a formation - he was looking to his lead. If the lead was slightly out of position, then he could easily have inadvertently put the P-63 in harms way.
Note - "COULD" there are many possibilities.
 
The aircraft are seen in the video's, he was in flight of 3, p51, p63 and b17. the videos show clearly, he was travelling faster than the p51 and b17, also turning inside the path of the b17, his line-of-sight would have been compromised by his right wing. This will all come out in the official investigation.
 
Didn't fatigue become an issue when planes were being pressurized ( like the Comet) and the structures optimized (like Gen 4 fighters, F-16, F-15). Prior to these, structures were designed for infinite life and for the predicted life of the aircraft fatigue didn't come into play? It may have been assumed the earlier planes would be retired or shot down before fatigue was an issue, let alone the engineering of fatigue analysis was in its infancy. Asking this as a question, not pretending to be an expert.

Wings/Airpower had an article about the B-47 and it's fatigue failures. When tactics changed from high altitude bombing to low level penetration and a pop up for bomb delivery, the primary structure suffered fatigue. The pins holding the wing spars together suffered from fatigue and the wings literally fell of the aircraft. The USAF did not regret retiring the B-47.
 

Pitting corrosion causing cracking was identified as an issue in the 30's.
 
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