The importance of availabilty.

[michael rauls]

I was thinking about how important availability is and how it often gets overlooked in favor of performance stats.
Can't remember which one but one of the commanders in the US Navy was quoted as saying in reference to a compairison of the F6F and Corsair " the Corsair was a better plane 2 days a week, give me Hellcats any day" which I took to be a reference to the difference in availability between the two types, 60% for the F4u and over 90% for the Hellcat( so I have read anyway).
Regardless if those percentages are accurate I can see how what may appear to be the lesser of two types by looking at performance stats might really turn out to be the better choice if there is a big availability difference between the two.
Would love to hear others thoughts on this as well as other examples.

 

[pbehn]

Without the Hurricane the RAF wouldn't have had a fighter force worth the name in the early part of WW2, I believe Stalin said quantity has a quality of its own.

 

[mikewint]

My vote is on availability. Something is better than nothing. What good is the most advanced "does everything" aircraft if you don't have any or they're not ready to fly? One of my concerns with our latest (US) high tech fighter/bomber/stealth aircraft. There is so much high tech equipment to maintain and millions of lines of complex code....what becomes of them when you don't have the leisure and/or parts to keep them maintained to the high standards required? Aircraft so expensive that they can't be risked if someone could shoot one down?

 

[pbehn]

The whole Spitfire story after the MkII was about more now than better later. Both the MkV and MkIX were less advanced designs than their previous MK numbers. A similar story with the Typhoon and Tempest with improvements being overlooked just to get more now rather than later.

 

[michael rauls]

The whole Spitfire story after the MkII was about more now than better later. Both the MkV and MkIX were less advanced designs than their previous MK numbers. A similar story with the Typhoon and Tempest with improvements being overlooked just to get more now rather than later.

Good point on the Spitfire and something that seems to be a recurring theme with alot of types.
Something interesting that occurred to me about this is the interplay of percentages between availability and performance. Obviously its sliding scale up to a point but what percentages of each dynamic balance. I.e. does a 10% better availability of one type equal a 10% greater performance of another type all other things being equal( which of course they never are but for the sake of discussion) or would it take 20%?
Don't know but interesting to think about.

 

[pbehn]

Good point on the Spitfire and something that seems to be a recurring theme with alot of types.
Something interesting that occurred to me about this is the interplay of percentages between availability and performance. Obviously its sliding scale up to a point but what percentages of each dynamic balance. I.e. does a 10% better availability of one type equal a 10% greater performance of another type all other things being equal( which of course they never are but for the sake of discussion) or would it take 20%?
Don't know but interesting to think about.

That was just concerning production numbers which is the first issue in "availability". The Hurricane had "it" over the Spitfire in every respect except performance, easier to build, easier to repair, Park even had one as a runabout. The Fw 190 had issues at the start getting it into reliable service, which probably was just a result of it being pushed into service too quickly. Same for the P-39, as delivered to the UK the first variants of the P-39 was more of a danger to its own pilots than the enemy but eventually the Russians loved them. It just wasn't "sorted".

 

[ThomasP]

Good question, and one my wargaming friends and I have been debating for years.

PRAM-D (Producibility, Reliability, Availability, Maintainability, Durability)

Although the acronym PRAM-D (or more usually Producibility and RAM-D) is a modern one, the concepts behind it are as old as the ancient civilizations with military services.

For anyone not familiar the acronym, the idea revolves around the fact that if you can not effectively produce a weapon system (whether due to complexity and difficulty, or acquisition problems such as cost or politics), if it is not reliable (ie how often it breaks down on its way to or during battle) and you can not then maintain it (due the time required and/or availability of trained personnel), or if the weapon system can not survive the environment (ie durability - whether due to nature, combat, or ineptitude of the operators) the availability drops to unacceptable levels.

The example of the Spitfire and Hurricane mentioned above is, I think, a good example of the trade-offs involved. The UK prior to and during the war had somewhat limited production resources (at least in comparison to the US) and did not have the time (or personnel?) to effectively retool with the latest and greatest manufacturing equipment. Many of the aircraft structures were designed to use the already available ability of the industry, in some cases resulting in seeming archaic and inefficient production.

Hawker used an evolutionary design and used (for the time) a conservative production method for the Hurricane, ie Warren truss steel tube structure, supplemented with wood and fabric covered surfaces on the fuselage. It allowed relatively easy training of personnel and the tooling was readily available. I do not recall any mention of unavailability of the Hurricane during the war, even during the BoB there were significantly more Hurricanes available than pilots.

Supermarine, on the other hand, adopted the monocoque construction for the fuselage and stressed skin structure for the wing (which for the time was somewhat new at least as far as implementation) and a novel idea for the main spar. This was partially responsible in a significant delay in initial production and procurement (which I think continued through the BoB period and afterward for a while). As mentioned up-thread, it was significantly more difficult to repair than the Hurricane.

Another example, and one of my favorites, is the Vickers Wellington. Vickers chose a revolutionary method of construction, and implemented the tooling up and production superbly (at least in my opinion). The Wellington was (I think) the third most produced combat aircraft by the UK at 11,000+, surpassed only by the Spitfire and Hurricane. Despite the adoption of hybrid geodetic framing, I do not recall any mention of delays or difficulties in production, or unusual problems with reliability of the structure or maintaining the aircraft.

 

[Conslaw]

Good point on the Spitfire and something that seems to be a recurring theme with alot of types.
Something interesting that occurred to me about this is the interplay of percentages between availability and performance. Obviously its sliding scale up to a point but what percentages of each dynamic balance. I.e. does a 10% better availability of one type equal a 10% greater performance of another type all other things being equal( which of course they never are but for the sake of discussion) or would it take 20%?
Don't know but interesting to think about.

I tried to start a thread sometime back to see if anyone had actually tried to infer a formula for the optimal rate of substitution of an inferior aircraft for a superior one. What prompted my speculation is that late-war Japanese fighters didn't do appreciably better than the A6M Zero against US Navy fighters. I also note that the F2M "wilder" Wildcat did as well statistically as the F6F or F4U. It is likely that the F2M almost always fought with numerical superiority against kamikazes and their inadequate escort.

 

[pbehn]

The example of the Spitfire and Hurricane mentioned above is, I think, a good example of the trade-offs involved. The UK prior to and during the war had somewhat limited production resources (at least in comparison to the US) and did not have the time (or personnel?) to effectively retool with the latest and greatest manufacturing equipment. Many of the aircraft structures were designed to use the already available ability of the industry, in some cases resulting in seeming archaic and inefficient production.
.

In the summer of 1940 the UK started to out produce Germany in single engine fighters and continued to until 1943. The USA massively out produced everybody later but in 1940 the factories and their designs that did so were a work in progress.

 

[Glider]

Look at Tanks, Sherman and T34 basic reliable tanks outclassed by the Panthers and Tigers but were available in numbers
Look at Warships, in particular the Flower Class corvettes which couldn't be more basic, or any ships such as the Liberty Ships the C47 of the seas. The allies would have been in serious trouble without either of them

 

[pbehn]

Look at Tanks, Sherman and T34 basic reliable tanks outclassed by the Panthers and Tigers but were available in numbers
Look at Warships, in particular the Flower Class corvettes which couldn't be more basic, or any ships such as the Liberty Ships the C47 of the seas. The allies would have been in serious trouble without either of them

The Liberty ships were high tech and needed a revolution in production metallurgy to make them a success. The problems involved in them gave birth to the British Welding Institute and the development of all sorts of plate and weld testing like Charpy and "Battelle" tests.

 

[Glider]

The Liberty ships were high tech and needed a revolution in production metallurgy to make them a success. The problems involved in them gave birth to the British Welding Institute and the development of all sorts of plate and weld testing like Charpy and "Battelle" tests.

My understanding was that the Liberty Ship was a basic design modified to simplify the build and to allow for welding instead of riveting techniques.

 

[pbehn]

My understanding was that the Liberty Ship was a basic design modified to simplify the build and to allow for welding instead of riveting techniques.

Exactly, it was Submerged Arc Welding, which was in its infancy and needed all sorts of improvements in plate production technology as well advances in the welding itself. The basics of it and the tests introduced are still standard in welding technology, although the Battelle test has been renamed a Drop Weight Tear Test. I am not disagreeing with your point, it was a very simple design using very high technology for the time, until this technology was perfected some ships broke in two. Its like saying a jet engine is a simple design, it has only one moving part, it "just" needed huge leaps in material technology and knowledge of fluid mechanics, combustion and fuel technology.

 

[Barrett]

Lenin usually is credited with "Quantity has a quality all its own" but wouldn't be surprised if Stalin Himself usurped it!

Certainly the Corsair was more maintenance intensive than the Hellcat, but by the time F4Us went to sea at the end of 44 my impression is that the two were comparable. I see little difference in sortie generation between the two from the fast CVs. Vought and the Navy put company tech reps right up front, and that helped a lot. Just FWIW.

 

[BiffF15]

Lenin usually is credited with "Quantity has a quality all its own" but wouldn't be surprised if Stalin Himself usurped it!

Certainly the Corsair was more maintenance intensive than the Hellcat, but by the time F4Us went to sea at the end of 44 my impression is that the two were comparable. I see little difference in sortie generation between the two from the fast CVs. Vought and the Navy put company tech reps right up front, and that helped a lot. Just FWIW.

What made the Corsairs maintenance more intensive?

 

[Dimlee]

Look at Tanks, Sherman and T34 basic reliable tanks outclassed by the Panthers and Tigers but were available in numbers
Look at Warships, in particular the Flower Class corvettes which couldn't be more basic, or any ships such as the Liberty Ships the C47 of the seas. The allies would have been in serious trouble without either of them

Tanks... At the same time, T-34s, especially early series with 76 mm, were of abysmal quality and numbers produced dropped down quickly without any combat losses and even before reaching a battlefield. So final availability was undermined by (lack of) reliability.
Actually, it was typical for the Soviet war machine in general. Thousands of tanks abandoned in 1941 without a single shot fired, thousands of aircraft scattered around airfields and factories without spare parts, a huge fleet of submarines (the largest in the world before WWII) without adequate repair facilities, etc.
So, above mentioned PRAM-D was completely out of balance. P was given the ultimate priority while R and D were often neglected and M was limited by lack of training and infrastructure. As a result, Availability suffered. Due to wrong feedback or incompetence, most attention was given to P on account of other elements and it went on and on... Luckily the scale of the economy allowed that. And then Lend-Lease provided equipment which was better balanced in terms of PRAMD.

 

[nuuumannn]

Having the F4U and the F6F provided another benefit, just like the Hurri and Spit example - both firms building the types were geared up for war production of their own products and unlike firms such as Short Brothers and Brewster building other firms' aeroplanes because their own weren't matching up, which required training for personnel, retooling within the factories etc. The Allied wartime logistics machine was what really won the war in the West and the maintenance of steady unrelenting production and manufacture made a huge difference on the front lines.

 

[nuuumannn]

Due to wrong feedback or incompetence,

Yes, good point Dimlee, the environment Stalin's Soviet Union worked in was not wholly conducive to honest problem solving.

 

[Admiral Beez]

My vote is on availability. Something is better than nothing.

I wonder if that bodes true for Malaya in 1940-42. Had nothing, rather than the Brewster Buffalo been available as a fighter to the RAF in Malaya would it be any worse? I would argue that in this case nothing might have been better than something. With no fighter, any pretence of a credible defence worthy of sending Force Z and >60,000 reinforcements would have been weak. Nothing for air defence in Malaya May have saved thousands of British and Imperial lives.

 

[Conslaw]

I wonder if that bodes true for Malaya in 1940-42. Had nothing, rather than the Brewster Buffalo been available as a fighter to the RAF in Malaya would it be any worse? I would argue that in this case nothing might have been better than something. With no fighter, any pretence of a credible defence worthy of sending Force Z and >60,000 reinforcements would have been weak. Nothing for air defence in Malaya May have saved thousands of British and Imperial lives.

You can take this same logic further, and say that Japan would have been better off without the A6M Zero. Without a fighter to achieve air superiority of the vast Pacific, would Japan have even taken on the Western Allies?