WW II aircraft fatigue life

[Thumpalumpacus]

I saw nothing in the Dallas videos that indicated structural failure. I think wlewisiii brings up the only real point worth mentioning about grounding, that of preserving our heritage, but even then that's up to the owners so long as the plane can get an airworthiness cert.

 

[FLYBOYJ]

Now this did not help fatigue life...

 

[SaparotRob]

I would've loved to have seen that.

 

[Avn-Tech]

The Smithsonian restored George Washington's hammer and replaced the Handle. Years later they restored it again and replaced the head due to trust. So is it George Washington's hammer anymore?

Don't get me wrong, I am not against museums. I see a need for both flying aircraft and static display aircraft.

For all those who say the aircraft belong in museums, how many aircraft in museums have you funded? How many aircraft have you saved from being scrapped?

 

[GrauGeist]

Many warbirds that are currently flying are rarely 100% original.
Some have been built from the ID plate up.

As for fatigue, which gets more of a workout, a P-51D or the 172 at the local flight training center?

 

[Barrett]

Question, does anyone know if FiFi, the B-29 flys pressurized?

It does not. At least not the two times I was involved. The money-generating flights and cross-countries have no need to fly at altitudes where pressurization would help.

 

[BobB]

RAF lost about 20 Wellingtons during WWII to fatigue of tubular steel wing spars. There could have been fatigue failures during WWII that were just written off as unexplained aircraft losses or "The pilot must have overstressed it." I suspect that B-17 is like DC-3 in that they designed redundant load paths into the wing without that having actually been their intent. Australia fatigue tested hundreds of new & used Mustang wings so their data could be used to predict a fatigue life for the load spectrum experienced by typical civilian operations.

 

[Thumpalumpacus]

The Smithsonian restored George Washington's hammer and replaced the Handle. Years later they restored it again and replaced the head due to trust. So is it George Washington's hammer anymore?

Don't get me wrong, I am not against museums. I see a need for both flying aircraft and static display aircraft.

For all those who say the aircraft belong in museums, how many aircraft in museums have you funded? How many aircraft have you saved from being scrapped?

I've posted this before, and it's direct to your point: Ship of Theseus - Wikipedia

Visit your museums, and airshows, and Navy Days, and so on, and give support.

 

[Big Jake]

As an aeronautical structures engineer and Warbirds maintainer, here are my comments: (Warbirds are warbirds that are being operated today)

a. Non of the so-called warbirds (including the C-47/DC-3) were designed with fatigue life in mind. The concept was known but applicability wasn't. It took many years until the concept was understood and adopted. (As I recall, the first US fighter to have a fatigue program developed for it was the F-16).
b. The warbirds were designed to fulfill certain missions. Non of the Warbirds which are flying today operate in conditions that come even close to the flight operations to which the particular aircraft were designed. (FiFi rarely flies above 10,000 and carries no payload except for a few people and fuel as do the B-17s, and just about every other type.)
c. The Warbirds that fly today are maintained by dedicated, experienced maintainers using modern practices and materials. That was not the case when these Warbirds were warbirds, maintained by teenagers off the farms and flown by people who knew that if they break the airplane then the Government will give them another one. At those times, carrying out a mission was number one priority - now it's safety (and compliance with regulations).
d. Anybody operating a Warbird is aware of the historical significant of the equipment he or she is operating. They take the best care they can though sometimes this is not enough.
e. What will eventually ground a Warbird will be shortage of funds, shortage of specific parts, availability of gasoline, insurance companies or lawyers. It will have nothing to do with technical issues.

 

[Big Jake]

Now this did not help fatigue life...

View attachment 695728

Fake! Never happened.

 

[Macandy]

Loss of Texas Raiders has prompted calls for grounding warbirds "because they're so old."

As I noted on a related thread, that's absurd. There were/are DC-3s and C-47s with 80,000 airframe hours.

So...
Wonder what Boeing computed the 17's fatigue life to be--assuming the company did so. Certainly few expected Fortresses to be flying in numbers 80 years downstream. (Last figure I recall was 30 or more.).

Also interested in fatigue life estimates for any other warbirds. (IIRC the average Lancaster lasted 14-15 sorties.)

Which is a good example…

The B-17 was not a 'good' warplane, it was seriously overbuilt and over engineered - see their long post war lives, but despite its fairly simple design, it was expensive and time consuming to build.

The B-24 however was a'good' warplane - despite being a much more complex design, it was built just strong enough to do the job, and the savings meant it could be massed produced easily and cheaply - but, it was fragile and they went quickly 'war weary' and they quickly died out after the War.

Early B-17 54,800 man hours
Late B-17 18,600 man hours

Early B-24 24,800 man hours
Late B-24. 14,500 man hours

 

[SaparotRob]

The B-17 was not a good warplane. Hmmm. The things one learns here. Just not from you.

 

[BlackSheep]

Now this did not help fatigue life...

View attachment 695728

Sentimental Journey is my girl! A "10" at the 1 spot!!!

 

[GrauGeist]

Early B-17 54,800 man hours
Late B-17 18,600 man hours

Early B-24 24,800 man hours
Late B-24. 14,500 man hours

And how long did it take to ramp up mass production and start getting other companies to provide out-sourced parts to streamline that production.

Those number being just tossed ot there without context literally mean zero.

 

[FLYBOYJ]

The B-17 was not a 'good' warplane, it was seriously overbuilt and over engineered

So I guess I would want to go into combat with an aircraft that was under-built and under-engineered

 

[FLYBOYJ]

Fake! Never happened.

Aghast! You mean the Confederate Air Force lied about this?!?!?

 

[ww2restorer]

Question, how many of the so called "warbirds" are actually combat vets? from what I personally have seen, most were constructed after WW2 ended, so never flew in a combat roll, either MAUW or Altitude. Take for example, most B17 were used in firefighting or private exec. work.

 

[GregP]

Most B-17s saw military use as combat aircraft or in crew training in the U.S.A. It was only AFTER military use they got surplussed. Very few B-17s were exactly "low-time" birds when surplussed. A few were, but not many. The Planes of Fame has the B-17 that was the last one in active U.S. military service (Picadilly Lilly). While it is NOT a low-time bird; neither is it a high-time bird.

 

[BlackSheep]

Which is a good example…

The B-17 was not a 'good' warplane, it was seriously overbuilt and over engineered - see their long post war lives, but despite its fairly simple design, it was expensive and time consuming to build.

The B-24 however was a'good' warplane - despite being a much more complex design, it was built just strong enough to do the job, and the savings meant it could be massed produced easily and cheaply - but, it was fragile and they went quickly 'war weary' and they quickly died out after the War.

Early B-17 54,800 man hours
Late B-17 18,600 man hours

Early B-24 24,800 man hours
Late B-24. 14,500 man hours

"….over engineered.."
Care to elaborate?

 

[GrauGeist]

"….over engineered.."
Care to elaborate?

I suspect that translates to "robust", because those B-17s could absorbe battle damage like no other machine ever made...