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I can't see any other threads about this, and thought it might be an interesting subject
Whilst characteristics like combat capability, engines and armament are more often talked about, I feel like the quality-of-life factors of an aircraft are often underrated.
Which WW2 aircraft gained a reputation from their crews and mechanics for being easy to work on and maintain, and requiring few resources to field/being logistically uncomplicated?
This is regardless of nationality, though I suppose later on in the war, the Axis nations would start to appreciate their more economical aircraft more, wouldn't they?
This is talking about how easy they are to repair, and how much resources they use up, not how durable their airframes are during combat, though I suppose that could factor into it.
Examples would be appreciated for each of the following roles:
Observational
Multi-role
Fighter
Light Bomber
Medium Bomber
Heavy Bomber
When it comes to claims the Hurricane had easier maintenance that requires some sort of measurement, it had lots of common parts with the Spitfire, but was, for example, the Spitfire hydraulic system more/less complex and easier/harder to service? People talk about hits on the rear fuselage, what about damage to wing surfaces, any difference in repair/maintenance effort between the two different types? And so on.
The loss figures are there because of the Hurricane was more rugged claims. Yet a greater percentage of Hurricanes hit by enemy fire were lost using the Bungay figures, while the other set of figures says 1.1 Spitfires were damaged for every one lost, versus 0.84 Hurricanes damaged per loss. So how do these results fit the more rugged idea? Both airframes would have the same designed strength factors.
Two sets of data. From Wood and Dempster, the Narrow Margin, Appendix 15.
100% Some folks can't grasp that REPAIRING an aircraft and ROUTINE MAINTENANCE are two different animals!!!The reality is that such things cannot always be measured through figures alone.
They don't inform about reliability of maintenance though, so their application here serves no real purpose. As Joe highlighted, damage repair is a separate issue to scheduled maintenance that might inform reliability statements.
Actually you make a great point!Least resource intensive and easiest to maintain aircraft of WWII ?
Easy. Breda BA.88. Pop it onto an airfield as a decoy and walk away.
Reliability can be a synonym for serviceability which is measured all the time, also the abort rates, again measured all the time. Which is different to resouces required to achieve a given level. Manuals on what maintenance is required, when and how much effort is required do that, plus the costs of spare parts, since ease includes paying for everything, dropping something like a replacement radio in can be "easier" than spending the time testing and diagnosing a problem.The reality is that such things cannot always be measured through figures alone. As I have mentioned, reliability of a type is not a simple metric to assign a figure to and it depends on so many factors..... Line servicing is very different to what is called "Depot level' servicing, where the aircraft are sent away for major work done to them, so context has to be taken into ccount.
Yet ruggedness is also a synonym for ease of maintenance, the rugged bush aircraft, able to keep going when others cannot, accept hand landings, while being cheap to run. In any case note how many times rugged has been mentioned already and as noted rugged does play a part in determining things like the total loss to damaged ratio and therefore maintenance/repair loads separate from the new production requirements.They don't inform about reliability of maintenance though, so their application here serves no real purpose. As Joe highlighted, damage repair is a separate issue to scheduled maintenance that might inform reliability statements.
Where does this come from? What age does the book have to be before we can rely on the figures? Wood and Dempster (first edition in 1961, the edition I am quoting from is from 1969) were able to obtain access to data not yet available to the general public, it means their data is over 80 years old. Has there been a major recalculation of the RAF lost and damaged finding major flaws in what the RAF was telling itself? Are you claiming the authors did their own calculations rather than reproducing the official statistics? Also I have given two other sets of data, which are more modern, all 3 sets are consistent.I wouldn't rely on Wood and Dempster's figures too closely, they have almost certainly been superceded as the book was published more than 50 years ago.
Errr, no - I don't know if you ever worked around aircraft as it seems you're inventing your own definitions. Serviceability is defined as the amount of effort it takes to perform a maintenance task. If it takes me an hour to change the brakes on aircraft "A" and two hours to change the brakes on aircraft "B" it's obvious which aircraft has better serviceability for that task. Compare the entire maintenance schedule of two aircraft (ex. Spitfire/ Hurricane) and that will give you an indication which aircraft has "better serviceability."Reliability can be a synonym for serviceability which is measured all the time, also the abort rates, again measured all the time.
You're convoluting several maintenance functions into one. Cost factor of "Rotable Parts" (look up the definition) and other components are factored in to a sustainment cost. This can be determined on the SCHEDULED maintenance performed as most if not all maintenance manuals are going to tell you what rotables, filters, hardware is going to be changed during SCHEDULED maintenance. Your example on troubleshooting a radio WOULD NOT be considered scheduled maintenance!!!Which is different to resouces required to achieve a given level. Manuals on what maintenance is required, when and how much effort is required do that, plus the costs of spare parts, since ease includes paying for everything, dropping something like a replacement radio in can be "easier" than spending the time testing and diagnosing a problem.
Again, repairing damage, be it from combat, wear and tear or operational damage is different matter.Ease of damage repair requires the accounting of the effort in repairing large enough numbers of damaged airframes to smooth out all the variables in what damage was taken. Then comparison with other types. That covers the mechanical engineering. It still has to note the "ruggedness", if one type was better able to return with damage than another.
And again you're 100% incorrect. Scheduled maintenance tasks can and were quantified to the point where it can be predicted exactly how long it would take to perform planned inspections and maintenance. This was the case during WW2 and is the norm today. Now anything found outside of SCHEDULED maintenance would be considered a REPAIR (in certain organizations referred to as "non-routine" or "over-and-above" tasks). All of this includes scheduled maintenance at the line and depot level.The definitions of line servicing and depot servicing are not useful in finding out resources/easy maintenance issues. The hours and parts required for each type of service would be measured, those figures are required.
YES!!! put all the expensive parts of maintenance on somebody else's account/tabGliders.
So when a unit reports x% of its aircraft serviceable, how much effort does that represent? Your definitions of serviceability and reliability are at an individual aircraft level. Serviceability and reliability as I am using the terms above is at the unit level, what % of the force can be usually expected to be available day to day, how many abort missions because of faults.Serviceability is defined as the amount of effort it takes to perform a maintenance task.
Agreed, I was actually but unclearly pointing out how you can cost and effort shift depending on what is important, dropping a new radio in as a time saver if you want to turn the aircraft around, as is sending aircraft away and receiving new ones to keep the load down on the unit but serviceability up. Everyone has encountered the better way of doing things that has been stopped because it costs shifts onto someone powerful enough to resist the change. The fighter pilot congratulating himself on returning his badly damaged fighter met with the maintenance crew pointing out that means they have to fix it instead of receiving a new one.Your example on troubleshooting a radio WOULD NOT be considered scheduled maintenance!!!
Wear and tear is damage, versus being part of routine maintenance? Apart from damage there is what a squadron can expect to take care of during routine operations and what happens in an emergency. The Battle of Britain was an emergency situation but all we have is data showing the numbers of damaged aircraft repaired by the combat units or taken away to be repaired in a situation where the operational airfields were taking damage, degrading their ability to perform maintenance, and risking the safety of leaving aircraft there to await maintenance, with aircraft taking all sorts of damage amounts, where it seems Hurricane squadrons were on average bigger than Spitfire ones and probably other factors as well.Again, repairing damage, be it from combat, wear and tear or operational damage is different matter.
Can you please reread my words? And note you are essentially agreeing with me while saying I am wrong? In particular my second sentence? I was pointing out giving a definition do not help finding what resources are required and therefore the ability to find one type was more reliable, rugged, better nose art or whatever.And again you're 100% incorrect.
Why add the mention of repair, which by definition tends to be non scheduled, in "line servicing and depot servicing"? So something unexpected, the need for a repair, can be scheduled?Now anything found outside of SCHEDULED maintenance would be considered a REPAIR (in certain organizations referred to as "non-routine" or "over-and-above" tasks). All of this includes scheduled maintenance at the line and depot level.
Will this help?Again, I don't know if you have any experience in this area,
Apart from similar forms/checklists. The RAF went to planned flying, which was efficient in its use of maintenance personnel at the expense of breaking the direct link between them and an individual aircraft which had its costs.I am not sure what the RAF used but it wouldn't surprise me if their processes were similar
You would think so, but I was just reading yesterday that in the run up to D-Day lots of gliders had been made and stored for a long time, some were getting worried that they may be going mouldy with damp or eaten by insects and vermin. How expensive is a single use item, that you cant use?Gliders.
"Effort?" You're asking for an enigma. It depends on how many aircraft are in the unit, what scheduled maintenance is due and how many aircraft are "mission capable," (term is mentioned below)So when a unit reports x% of its aircraft serviceable, how much effort does that represent?
Nope - it's at the individual aircraft level. You can have two aircraft of the same type (say two single engine fighters). One may take 3 days to do a planned phased inspection, the other may take 4.Your definitions of serviceability and reliability are at an individual aircraft level. Serviceability and reliability as I am using the terms above is at the unit level, what % of the force can be usually expected to be available day to day, how many abort missions because of faults.
Again, this is apples and oranges - Repairs vs Scheduled Maintenance.Agreed, I was actually but unclearly pointing out how you can cost and effort shift depending on what is important, dropping a new radio in as a time saver if you want to turn the aircraft around, as is sending aircraft away and receiving new ones to keep the load down on the unit but serviceability up. Everyone has encountered the better way of doing things that has been stopped because it costs shifts onto someone powerful enough to resist the change. The fighter pilot congratulating himself on returning his badly damaged fighter met with the maintenance crew pointing out that means they have to fix it instead of receiving a new one.
No - wear and tear is EXPECTED. That's why some components and in some cases parts of the airframe actually have a "shelf life" where you change out the whole unit based on an hourly or cycle requirement.Wear and tear is damage, versus being part of routine maintenance?
Again - you're talking REPAIR (and in the case of the BoB repair from battle) vs Scheduled Maintenance.Apart from damage there is what a squadron can expect to take care of during routine operations and what happens in an emergency. The Battle of Britain was an emergency situation but all we have is data showing the numbers of damaged aircraft repaired by the combat units or taken away to be repaired in a situation where the operational airfields were taking damage, degrading their ability to perform maintenance, and risking the safety of leaving aircraft there to await maintenance, with aircraft taking all sorts of damage amounts, where it seems Hurricane squadrons were on average bigger than Spitfire ones and probably other factors as well.
I re-read your words and so far you seem not to understand that scheduled maintenance is a known factor. It is defined and can be measured to include parts and manpower, something you cannot do when addressing DAMAGE, be it from combat or aircraft abuse/ accidentCan you please reread my words? And note you are essentially agreeing with me while saying I am wrong? In particular my second sentence? I was pointing out giving a definition do not help finding what resources are required and therefore the ability to find one type was more reliable, rugged, better nose art or whatever.
No because once again you're not grasping this, probably because you never worked or been around this environment. Again a repair is a non scheduled maintenance action. Can you schedule a repair into scheduled maintenance? Sure - but in doing so it is not a measure of how "serviceable" the given aircraft really is!Why add the mention of repair, which by definition tends to be non scheduled, in "line servicing and depot servicing"? So something unexpected, the need for a repair, can be scheduled?
Will this help?
Agree - see my comments aboveAll machines have regular scheduled maintenance making it easy to compare the costs, ultimately in money but also the times between maintenance and the time required for the work. Sometimes the scare or more valuable commodity is time, others money.
OK...Next is damage repair, which in this case is about Hurricane versus Spitfire, with only anecdotal evidence about damage to specific parts of the airframe. Before you even start on the repairs accounting you need to check whether one type or the other could make it back with on average heavier damage than the other. Something which tends to be called rugged.
Again, ok...Apart from similar forms/checklists. The RAF went to planned flying, which was efficient in its use of maintenance personnel at the expense of breaking the direct link between them and an individual aircraft which had its costs.
I am well aware of how the USAAF classified mishaps and in my previous posts I've showed how it evolved in to the mishap rating system, you're posting meaningless numbers that have absolutely no bearing here as you're convoluting maintenance into operational statistics and still discussing "unscheduled maintenance" into the fray. You can't wrap your head around the fact that Scheduled Maintenance is a known quantity - a maintenance planner, scheduler or maintenance officer can accurately determine to a great degree how long a scheduled maintenance activity (Phase inspection. hourly inspection, etc.) is going to take. Damage repair, especially combat damage is an unknown until the aircraft can be inspected and a repair can be determined. I'll repeat again - this is OUTSIDE the scope of scheduled maintenance.The USAAF has far more detailed figures published on issues like accident and loss rates, serviceability and abort rates than the RAF. So 1,018 out of 4,228 8th Air Force B-17 losses on operations were Category E, 24.1%, while 544 out of 1,562 8th Air Force B-24 losses on operations were Category E, 33.4%. On that basis the B-24 was more rugged, more chance of returning with write off levels of damage.
When it comes to accidents they include things like being hit while parked, the ground crew setting the aircraft on fire as well as take off accidents, collisions, etc. The USAAF usually classified the damage taken between 1, minor, and 5 salvaged/write off. As far as I can tell some level 3 and most level 4 damaged aircraft were scrapped. The B-17 accident list I know of has 4,021 accidents, 3,632 of which have a 1 to 5 damage level recorded, 27% level 4, 23% level 5. For the B-24 3,653 accidents, 3,288 of which have a damage level recorded, 35% level 5, 30.4% level 4. So 50% of B-17 accidents probably meant scrapping versus 65.4% of B-24 accidents.
That says the B-24 was at least more likely to sustain greater damage in an accident. And heavily damaged aircraft returning tend to make crash landings or be abandoned in the air if the landing risk was judged too great. So how much of the higher percentage B-24 of making it back with write off damage is actually due to on average taking more damage during the landing? Accidents percentage B-17 50.0, B-24 65.4, 8th AF category E percentage times two B-17 48.2, B-24 66.8
On this evidence, which was the more rugged? That is able to take more damage but make it home? To remove the effects of the 1943 losses, for 1944 only 20.4% B-17 losses were write offs, 28.7% B-24, loss rates B-17 2.0%, B-24 1.8% of credit sorties.
And the problem is you have folks who read all about aircraft maintenance through various publications and many times you have authors writing about this stuff who never been around aircraft, let alone twisted wrenches or smacked rivets.That's a problem I run into. Proper terminology. I'm familiar with the differences between repair and scheduled maintenance. I worked with Yardmasters (the railroad equivalent to an E-8, methinks) and was involved in moving equipment around for both services.
I believe a majority of that would be done at the NCO club.I am intrigued by the scheduling of nose art evaluations, though.
And Mike, this is all good when addressing REPAIRS, especially when dealing with aircraft being flown in combat which is obvious. It's also evident that some scheduled maintenance will be undertaken at this time. The amount of time and effort it takes for repairs will obviously vary between aircraft and units. For example, I can have a training unit of 12 Spitfires of which 10 are flying at any given time and are just used for training, then I have another squadron of the same number experiencing heavy combat, it going to be quite obvious which unit was going to see more downtime, so to get a better picture of operations, you separate the normal SCHEDULED maintenance from the repairs and this will give you a true matrix of were you stand for both situations.Hi
Dowding's Battle of Britain Despatch has a mention on servicing and the repair organization:
View attachment 692107
View attachment 692108
So to aid maintenance with the aircraft dispersed around the airfield 'tents' were used to help the ground crew (also seen in the Battle of France). To prevent the build up of damaged aircraft at operational airfields the aircraft concerned would have to be flown direct to a repair depot or transported by road, not kept in 'vulnerable' hangars on the airfield.
Other statistics and chart from the AHB Narrative of BoB:
View attachment 692109
View attachment 692110
Mike