B.o.B. Lanc this evening

And what they are now valued at by the MOD for valuation purposes

Life expectancey is the time of it remaining airbourne until shot down if I recall.Six weeks for a Spit I think.

…and yet in that six weeks it still couldn’t get to Berlin!

I don’t think a Spitfire could fly for six weeks… 😉 ‘In front line use’ is what you mean, rather than ‘airborne’. I’m not having a go, just pointing out if you say something that means something different to what you thought, that’s how these misunderstandings (the 25 missions…) start. There’s a world of difference and an advertising standards complaint between: ‘The best lager in the world’ and ‘Probably the best lager in the world.’

I like the car market analogy, though and I can see its validity. However, the accountants might also say that, once it has become a ‘clasic’, its value increases in proportion to rarity and to some extent, its marque.

Indeed. However, the original value has normally been fully depreciated. No cars have an ‘anticipated classic value’ built into the cost analysis at building.

The analogy is robust. HM Government has fully depreciated all Lancasters, Hurricanes and Spitfires to ‘zero’ – certainly as ‘military assets’. However, the BBMF’s kit must be now ‘valued’ by the MOD at some nominal figure, as they have a financial value and also an intangible value as commemorative historic equipment. It would be interesting to know what the RAF’s ‘value’ was on the THUM flight Spitfires and 44 Squadron’s Lancaster and their last Hurricane at the nadir of their value – when they were too old to be useful, too new to be valuable.

Cheers

Components are also “relifed”, the original time of expiry being too conservative ,and operational duties showing that said component can safely last much longer; the RR Viper is a case in point ,RR will relife it after inspection(although apparently the inspection costs more than a new out of the crate Viper!). The motor industry often works the other way round ,originally setting long servicing intervals and shortening them when the “customer” brings back a broken bit! Probably the greater of the two enemies to replacement structural components, is corrosion, as opposed to fatigue; these days at least A/C normally get nowhere near their operational limits, but it still rains ,especially at airshows!, and it is that rain water that sets off corrosion, much of which cannot be seen. Another comparison between the motor and aviation industries is perishables; in the car world the “old dear” that only does 30 miles a year and only on sunny days, will still need the “rubber” seals in the braking system replaced at much the same time as everybody else, and so it is with A/C.

There is no such thing as a ‘stupid’ question….

… but there an an awful lot of inquisitive idiots…

Trying to remember where I first heard that….I have a feeling it was Dx 😉

Life expectancey is the time of it remaining airbourne until shot down if I recall.Six weeks for a Spit I think.And yes skill is something that is slowly being lost.On our project I was the only one with sheety experience.I am trying to pass that skill along to the rest of the guys and I hope they can too pass it on to others.The fatigue life of the part depends on many things.In war time it would have to do be under huge stresses in combat,tight turns,corkscrews,dives,pullouts,where today a few passes over an adoring crowd would be a lot sedater.

40 missions sounds more realistic, although I was sure the caption/passage reads 40 hrs. I’ll have to check and make sure I’ve got it wrong. However, after having ha d quick read through it, I can see where you reference to hours comes from, as there is a short section on servicing which does state something along the lines of ‘…those aircraft lucky enough see 500 hrs…’ before they saw any sort of major serving. The intervals, apparently were 500 and 1000 hrs, by any stretch of the imagination, plenty of ops.

So what is/was the life expectancy of the Lancs main spar, as its probably one of the hardest worked, non-‘mechanical’ parts of the airframe?

I like the car market analogy, though and I can see its validity. However, the accountants might also say that, once it has become a ‘clasic’, its value increases in proportion to rarity and to some extent, its marque. Mind you, I’ve seen a few cars on the Historic Rally Car Register and they driven just as hard now as they were when they were new! The same doesn’t appear to go for classic aircraft, perhaps for obvious and necessary reasons!

Coff coff,
Missions, not hours. 😉 It’s true to say that the aircraft were designed and built to fulfil a wartime job that would be measured in double digit operations or missions, treble digit hours.

But you could look at is as a variant of the car market. They are built to last a few years, giving value to the first couple of owners. It doesn’t mean that you can’t keep ’em going in the used car market and then the classic car role.

An accountant might say the aircraft had fully depreciated once they has fulfilled their number of missions.

Cheers

…

It’s not. Most / all W.W.II aircraft were built to a job which would last a very short time in modern eyes. In other words a Spitfire was expected to be in front line use for probably weeks, maybe months, certainly not years. But they’d go on to second line duties or foreign use, and be expected to last through that. They were, generally ‘overbuilt’ in being tougher than the front line environment/time required. In the case of the B-17, there’s no way it would all suddenly fall apart on the 26th mission! Engines, props, fittings and fixtures would be replaced as necessary, in service. If it became too much of a job, it would be junked and a new one from the production line would be taken instead. The allies’ production success was one of the war-winners, often overlooked.

…
Cheers

An interesting observation. I suppose one way of looking at it is the 25 hrs quoted might be referring to its expected operational life and not airframe life. I remember (but I’ll check again at some point in Lancaster At War (by Garbett & Goulding) mention is made that a Lancaster had a life expectancy of 40 hrs. You’re right JDK in that at 41 hrs, the whole thing would collapse in on itself. Does the ’40 hrs’ therefore refer to its life expectancy on operations? I.e, it wasn’t expected to last more than 40 hrs worth of offensive bombing missions? I found it odd when I first read it about twenty-two years ago and the direction of this thread has just reminded me of it! If it was only 40 hrs, then the Base Servicing stations or Bracebridge Heath would have been VERY busy, not just repairing battle damage Lancs but also replacing sometimes large portions of fatigued airframe!

Cheers James, saved me writing a long post!

Once these are used up????? Are there only a limited amount from original stock? Surely with todays modern toys in manufacturing more could be made?

I think that the rate that fuel is going up the raw materials are the last of our problems.

One of the myths that we get caught out by is that ‘modern’ tools, raw materials and techniques are always ‘superior’ or ‘more diverse’ than they used to be. This is simply not true.

While CAD CAM machining will do things that were done by hand, the skilled fitters of the W.W.II era are a rare breed today, and much of that skill has been lost; certainly in most engineering practices.

A number of materials, such as metal grades, wood sizes and shapes and perhaps most oddly, particular measurements (like imperial) are no longer made or available. You can’t just substitute a modern steel for a wing spar over a W.W.II type, as its different strengths will have a knock on effect to other parts – never mind certification issues which generally state that you have to use the original part or equivalent, or you are faced with an expensive and time consuming re-stressing of the calculations.

This is over and above relatively obvious changes like not using asbestos in the firewalls, caution over radioactive instrument paints and modern non-lead based paint on the aircraft. – Back then the concerns over chronic risks were either not known of simply ignored – W.W.II fire-fighters wore asbestos suits – a better example of chronic vs acute risk I can’t think of!

If this is the case and taking into account the age of the aircraft, how much of the original airframe exists on flying historic aircraft?

Would you like your answer by weight, volume or area? It’s a piece of string question, but the generic answer would be more than the cynics think, but a lot less than everything. Certain parts, on Spitfires say, or rarer machines have to be original as they haven’t been made since. Skinning and rivets are usually replaced. The RAF Museum has a diagram by their (static) Bulldog rebuild and it shows how much Skysport had to fabricate and where all the other bits came from.

I was speaking to a B17 junkie who told me that the B17 was only built for 25 missions. If this is true,…

It’s not. Most / all W.W.II aircraft were built to a job which would last a very short time in modern eyes. In other words a Spitfire was expected to be in front line use for probably weeks, maybe months, certainly not years. But they’d go on to second line duties or foreign use, and be expected to last through that. They were, generally ‘overbuilt’ in being tougher than the front line environment/time required. In the case of the B-17, there’s no way it would all suddenly fall apart on the 26th mission! Engines, props, fittings and fixtures would be replaced as necessary, in service. If it became too much of a job, it would be junked and a new one from the production line would be taken instead. The allies’ production success was one of the war-winners, often overlooked.

…will the Lanc take more punishment and be easier to field repair due to the seeminly modular construction of the whole?

There’s not as much to choose between the types as enthusiasts would like to believe, and the modular construction in operation and maintenance today is a minimal advantage. Both were well designed and effective bombers (to do very different jobs) and on just numbers (not a good measure, necessarily) the B-17 remains a better bet to fly in a commemorative role – having remained with a broad dozen plus in the air since W.W.II with a few dips below that number. The Lancaster’s been one military funded example for most of 30 years, followed by the Canadian Warplane Heritage’s example about 15 years ago. Ask the French – they retired their Aeronavalle Lancasters earlier than their IGN survey B-17s – but that’s more to do with the jobs than one type’s ‘superiority’.

If you are interested in how preserved aircraft are restored and maintained, three readable but technically sound books I’d recommend are Russ Snadden’s account of rebuilding ‘Black 6’ the Messerschmitt 109G-6 (a very original airframe, BTW) Graham Warner’s books on the Blenheim rebuilds – ‘The Forgotten Bomber’ and then ‘Spirit of Britain First’ and finally Robert Mikesh’s ‘Restoring Museum Aircraft’. Not in print, try www.abebooks.com or your library inter-loan service.

Cheers

There is no such thing as a ‘stupid’ question 🙂

Oh????? Dunno about that one 🙂

Pretty much (as far as ‘simple’ Permit to Fly aircraft are concerned anyway), most of the historic aircraft we enjoy today (the Spitfire , Hurricane, Mustang etc) do not have a finite airframe life, but their status as airworthy machines is maintained by a series of detailed inspections of various levels of complexity throughout the year coupled with (flying) time related prop and engine overhauls.

If this is the case and taking into account the age of the aircraft, how much of the original airframe exists on flying historic aircraft?

Yes it is a very big job but the Lanc as an airframe is made from a number of different ‘sub-assemblies’ and the main spar is a large part of the central fuselage/inner wing sub-assembly so it is possible to break the spar down and replace the sheet metal components and fixings. And yes, it does deserve it!

I was speaking to a B17 junkie who told me that the B17 was only built for 25 missions. If this is true, will the Lanc take more punishment and be easier to field repair due to the seeminly modular construction of the whole?

The spar is more of a built-up assembly than an individual part, so it can be replaced so long as the raw material, bults and rivets are still available.

I think that the rate that fuel is going up the raw materials are the last of our problems.

Ali

Shrivenham is between Swindon, Wiltshire and Faringdon, Oxfordshire and is the Royal Military College of Science. No aircraft facilities or runways.

TLC is short for Tender Loving Care 🙂

Crews as far as I am aware are all serving RAF staff, and what a great job they do to.

Look here for a more detailed look at the RAF Battle of Britain Memorial Flight. http://www.deltaweb.co.uk/bbmf/home.html although I think the ground crews should have their own section and quite rightly to. http://www.pa474.f9.co.uk/

B.P.

Oh right thank you very much for the information

James

I don’t know anything about the rules of keeping an aircraft in the air so a “possible” stupid question coming.

There is no such thing as a ‘stupid’ question 🙂

So the rules are “regardless of the age of the flying machine then these are the rules and it’s right across the board”.

Pretty much (as far as ‘simple’ Permit to Fly aircraft are concerned anyway), most of the historic aircraft we enjoy today (the Spitfire , Hurricane, Mustang etc) do not have a finite airframe life, but their status as airworthy machines is maintained by a series of detailed inspections of various levels of complexity throughout the year coupled with (flying) time related prop and engine overhauls.

I had heard it had something to do with the main spar but didn’t know that this particular part of the aircraft could be changed. Sounds like big job but with the Lanc it’s worth it.

Yes it is a very big job but the Lanc as an airframe is made from a number of different ‘sub-assemblies’ and the main spar is a large part of the central fuselage/inner wing sub-assembly so it is possible to break the spar down and replace the sheet metal components and fixings. And yes, it does deserve it!

Once these are used up????? Are there only a limited amount from original stock? Surely with todays modern toys in manufacturing more could be made?

The spar is more of a built-up assembly than an individual part, so it can be replaced so long as the raw material, bults and rivets are still available.

Not really. The Lancasters flying time is governed by the ‘life’ allocated to the main spar. This ran out of hours a few years ago and the structure was replaced allowing many more flying hours. Once these are used up (in many years time) the spar can be replaced again.

In common with all other aircraft the engines and props are also required to be overhauled after a certain number of flying hours but this is common to all aircraft and not something which is particular to PA474.

I don’t know anything about the rules of keeping an aircraft in the air so a “possible” stupid question coming.

So the rules are “regardless of the age of the flying machine then these are the rules and it’s right across the board”.

I had heard it had something to do with the main spar but didn’t know that this particular part of the aircraft could be changed. Sounds like big job but with the Lanc it’s worth it.

Once these are used up????? Are there only a limited amount from original stock? Surely with todays modern toys in manufacturing more could be made?

Ali

Ali

I heard somewhere that it only has a limited amount of flight hours left on that aircraft and then it will be grounded. Any truth in that?

Ali

Not really. The Lancasters flying time is governed by the ‘life’ allocated to the main spar. This ran out of hours a few years ago and the structure was replaced allowing many more flying hours. Once these are used up (in many years time) the spar can be replaced again.

In common with all other aircraft the engines and props are also required to be overhauled after a certain number of flying hours but this is common to all aircraft and not something which is particular to PA474.

But are the crews not part off the RAF. And where is Shrivenham and sorry but what is TLC knever heard off it beofore well apart from Tables ladders and Chairs 😀 James

Shrivenham is between Swindon, Wiltshire and Faringdon, Oxfordshire and is the Royal Military College of Science. No aircraft facilities or runways.

TLC is short for Tender Loving Care 🙂

Crews as far as I am aware are all serving RAF staff, and what a great job they do to.

Look here for a more detailed look at the RAF Battle of Britain Memorial Flight. http://www.deltaweb.co.uk/bbmf/home.html although I think the ground crews should have their own section and quite rightly to. http://www.pa474.f9.co.uk/

B.P.

😮 🙁 🙁 Hope its un-true be very sad if she is grounded.

James[/QUOTE]

I hope it’s un-true too but I just heard it somewhere so I thought I would ask.

Ali

91Regals post was posted about 6.30. Gotta hand it to the air and ground crews of the BBMF – the extra hours they must put in , missing out on family and friends to fly for us.

Yes, I know we’d all give our right hand to fly in ’em, but it dosn’t take away from all those weekends the boys and girls must work during the Spring/Summer.

The same thing struck me about all those years that Ray Hanna devoted to air displays. Well done all!

But are the crews not part off the RAF. And where is Shrivenham and sorry but what is TLC knever heard off it beofore well apart from Tables ladders and Chairs 😀

I heard somewhere that it only has a limited amount of flight hours left on that aircraft and then it will be grounded. Any truth in that?

Ali

😮 🙁 🙁 Hope its un-true be very sad if she is grounded.

James

Lovely to see the Lancaster back at Old Warden, espesialy after the reported trouble at Biggen Hill.

I heard somewhere that it only has a limited amount of flight hours left on that aircraft and then it will be grounded. Any truth in that?

Ali

Quite possibly – but then some smart**** would come along and say “no its B.o.B Memorial Flight” and tell you that Lanc starts with a capital ‘L’ – now that would be picky! 🙂

🙂