Life-span of a frequently used aircraft?

[Politician01]

I found a source which claims that the WW2 era aircraft were actually very fragile things - and that they had a life span of no more than a year if they were used frequently.

Does anyone have sources which would confirm or contradict this claim?

[phylo_roadking]

OP - I'm not sure that "fragile" is the correct word! "Prone to accelerated stress fatigue and wear" maybe...?

[Takao]

OP - I'm not sure that "fragile" is the correct word! "Prone to accelerated stress fatigue and wear" maybe...?

Yeah, those German 88s really accelerated the stress and wear on an Allied airframe!

[AVV]

Hello!
The life span depended, to a great extent, on construction of the planes - i.e. all-metal planes were more enduring than the planes of mixed construction.
For example, second prototype of Soviet ANT-42 (TB-7/Pe-8) heavy bomber (first flight 26.07.1938) was tested extensively before WW2, then it was repaired in 1942 and used as a combat plane. It made more than 120 sorties and and was written off in mid-1945.

Best regards, Aleks

[Mangrove]

I found a source which claims that the WW2 era aircraft were actually very fragile things - and that they had a life span of no more than a year if they were used frequently.

I believe this to be a mere myth, most likely connected to the relatively fast replacement rate of the USAAC aeroplanes. I have gathered some Finnish data of the flying hours of various individual aerocraft fuselages of the types used by the Finnish Air Force during the 1930s and 1940s. All of the sampled fuselages were removed from service due to fatigue, not because of e.g. battle damage, after the WWII.

Most UK-made Bristol Blenheim fuselages bought in 1938 flew between 600 and 800 hours before being removed from service between 1945 and 1957. Most Morane-Saulnier 406s received in 1940 from France were operated between 300 and 500 hours between 1940 and 1952.

Most Fiat G.50s received in 1940 from Italy flew between 300 and 400 hours during the next 10 or so years. The most flown Finnish Bf 109 fuselage (MT-452) flew 312 hours between 1944 and 1954. Another fuselage, MT-507, flew 273 hours.

The life span depended, to a great extent, on construction of the planes - i.e. all-metal planes were more enduring than the planes of mixed construction.

I can perform statistical analysis of the data I have, but as far as I can see with my naked eye, there is no correlation between the construction of the plane and the flying hours. Finnish Fokker D.XXIs, for example, have far more hours in average (between 600 and 700) than other fighter types as they were bought years before the WWII.

[Sid Guttridge]

Hi Mangrove,

I guess the definition of "worn out" varied with the availability of spares and replacements. The Finnish Air Force was particularly constricted and had to keep flying types that the original constructing countries had already taken out of service, whether fragile or not.

A relatively small proportion of Allied aircraft losses were actually in combat. For example, the USAAF lost hundreds of aircraft over Central and South America and barely any in combat (with U-boats).

Cheers,

Sid.

[Mangrove]

I guess the definition of "worn out" varied with the availability of spares and replacements. The Finnish Air Force was particularly constricted and had to keep flying types that the original constructing countries had already taken out of service, whether fragile or not.

I absolutely agree with you. The hours I quoted should be regarded as average maximum flying hours for a fuselage of that type. Since Finns either were enabled to manufacture spare parts for some types (Blenheim, Fokker) or had purchased lifetime supply of spares for their fleet (Bf 109, Ju 88), I can see no other reasons for removing particular fuselages from service after the WWII other than metal fatigue and/or obsolescence of the plane type.

[phylo_roadking]

"I guess the definition of "worn out" varied with the availability of spares and replacements"

...and of course the national experience To, say, senior RAF officers in WWII, the thought of aircraft types that would be obsolete within a couple of years, that came off the production line with their replacement(s) already flying as prototypes, the thought of that short sevice life of particular marks etc. must have seemed frighteningly short to men who early in the careers had flown in ex-WWI aircraft kept flying a for a decade or more out on the very limits of Empire - men like Harris who had flown in truly obsolete bombers in the Near East and India held together wih baling twine and wire as the termites ate through them faster than they could be repaired...

Another aspect of "fast" obsolescence is that the speed with which a particular combat arcraft became obsolete wasn't JUST set by improvements in the type and new types arriving from your OWN factories...just like tanks, and A/T guns, obsolescence could be forced upon you by the enemy's technical advances!

It's also fair to remember that OUR ideas of "long" service lives is set by modern aircraft These, for example...

Most UK-made Bristol Blenheim fuselages bought in 1938 flew between 600 and 800 hours before being removed from service between 1945 and 1957. Most Morane-Saulnier 406s received in 1940 from France were operated between 300 and 500 hours between 1940 and 1952.

Most Fiat G.50s received in 1940 from Italy flew between 300 and 400 hours during the next 10 or so years. The most flown Finnish Bf 109 fuselage (MT-452) flew 312 hours between 1944 and 1954. Another fuselage, MT-507, flew 273 hours.

...can't really be properly judged against the tens of thousands of flying hours a modern long-haul airliner will accumulate in its lifetime!

OR the hundreds of hours' per year primpimg and pampering and occasional complete rebuilds that surviving classic warbirds receive today ....to fly their few dozen display hours annually!

[Sid Guttridge]

I found this on the net:

"During the coruse of the Second World War some thirty-five (35) Lancaster's reached or supassed the 100 operational sortie mark. It is entirely possible that there may be several other Lancaster's which should be added to this list, but due to inaccurate recording keeping, sorties which they took part in were incorrectly recorded or credited to another aircraft."

Sid

[phylo_roadking]

I found this on the net:

"During the coruse of the Second World War some thirty-five (35) Lancaster's reached or supassed the 100 operational sortie mark. It is entirely possible that there may be several other Lancaster's which should be added to this list, but due to inaccurate recording keeping, sorties which they took part in were incorrectly recorded or credited to another aircraft."

Not every Lanc sortie in its service life was going to be a Berlin round trip, not by any means...but to find an "outside edge of the envelope"/ballpark figure, we can take, say, the return trip flying time to Berlin, multiply it by 100, and get a theoretical maximum number of operational flying hours for a 100-sortie aircraft...

And then remember how few of the ~7,370 built ever reached the 100-sortie mark!

[Sid Guttridge]

Absolutely, "few of the ~7,370 built ever reached the 100-sortie mark!"

However, those that did were presumably all "frequently used aircraft", as per the thread title.

The "INDIVIDUAL HISTORY of AVRO LANCASTER B.Mk.1 R5868/7325M" is on the internet at:

http://www.rafmuseum.org.uk/documents/c ... -R5868.pdf

It gives the following variations in flying times to the following targets:

Cologne: 3h 24m to 4h 45m.
Hamburg: 4h 18m to 6h 11m.
Berlin: 6h 31m to 8h 31m.

I guess the average would be aound 5 hours per sortie - or around 500-700 operational hours for these frequently used aircraft. This excludes any non-operational flying done for such things as delivery, testing, training, etc..

Cheers,

Sid

[phylo_roadking]

I guess the average would be aound 5 hours per sortie - or around 500-700 operational hours for these frequently used aircraft. This excludes any non-operational flying done for such things as delivery, testing, training, etc..

...which of couse "only" puts them in the same ballpark as the long- and well-maintained Finnish aircraft But any RAF Lancaster surviving to 100 sorties would ALSO have received an appropriate amount of servicing.,.

It's a pity we don't know more about these remarkable 35 - as in, what were their service lives like? A couple of years of high-intensity ops.....or 3-4 of average frequency like R5868? And of course...we know "100 sorties" but what actual ranges flown? And what were their servicing records like...frequent engine changes, any known issues etc.?

Any or all of those answers could change our initial impressions.

The RAF Museum file on R5868 is indeed informative - but just on the one notable aircraft We just don't know if that is typical of the other 34!

[Sid Guttridge]

Hi Phylo,

Certainly we don't know if this aircraft was typical of the other 34 centenarians, but I would suggest that there are a number of reasons to believe that it might be fairly so.

Typically Lancasters operated on bombing missions over North-West Europe, so their range of targets was likely to be similar. This one seems to have covered Germany fairly thoroughly, as would any Lancaster that flew that many missions. I would suggest that short-lived Lancasters are the ones that are more likely to have had atypical operational careers for statistical reasons.

If anyone wants to follow this up to see how typical this aircraft was, there is a basic list of the other known Lancaster "centenarians" at:

http://www.lancaster-archive.com/lanc_100%20ops.htm

In the context of this thread, the range flown is less relevant than the hours flown, as it is the accumulation of the latter that better represents the cumulative stresses and strains on the aircraft. For example, against a headwind to the target an aircraft would cover the same distance over the ground, but take rather longer. Likewise, the distance from home airfield to the target varied with the tactics employed.

If a picture is emerging on the limited evidence here available, it seems to be that multi-engined types achieved more hours than single engined types.

Cheers,

Sid

[Mangrove]

...can't really be properly judged against the tens of thousands of flying hours a modern long-haul airliner will accumulate in its lifetime!

If a picture is emerging on the limited evidence here available, it seems to be that multi-engined types achieved more hours than single engined types.

The most flown WWII-era aeroplane in the Finnish Air Forces was the Douglas DC-2-115E "Hanssin-Jukka". She was taken into use by KLM in 1935 and was given to the Finnish Air Force in 1940. Between January 1935 and September 1939, she had flown a total of 5072 hours.

During her life at the Finnish Air Forces, she flew 1274 hours between 1940 and 1949, and further c. 1200 hours between 1950 and 1955. She was removed from service after having flown c. 7500 hours. She had her engines overhauled once and had undergone two complete checks for her fuselage during the twenty years.

[LWD]

My uncle's B-24 flew from the US via Brazil and Africa to the UK prior to any combat missions. I think that was in excess of 10,000 miles at ~200mph that's at least 50 hours add training and testing time before deploying and training and combat time afterwards (30 missions x 4+ hours per mission and you are well over 200 hours.