A Critical Analysis of the RAF Air Superiority Campaign in India, Burma and Malaya in 1941-45

[Kevin J]

Do you have real source for that or are we back to the bearing failure thing again.

RR themselves only claimed a "life" for the Merlin in 1945 of 360 hours for a fighter engine, 420 hours for a bomber engine and 500 hours for a transport engine.
"The Merlin in Perspective- the combat years" Rolls-Royce Heritage trust Historical series No2 page 90.

You have to very careful reading and interpreting some of these figures.

For instance if you had 30 fighters with Allisons and ran them for 100 hours each (3000 hours total) and got 2 bearing failures you would be averaging one bearing failure every 1500 hours of operation. Do the same thing with 30 Merlin engines and if you had 6 bearing failures in 3000 hours of operation you would be averaging 500 hours between bearing failures.

It may not mean that the engines lasted either 1500 hours or 500 hours in service. Only a really desperate squadron commander or technical officer would fly a plane in combat that was hundreds of hours past the manufacturers recommended overhaul life.

The hours I listed earlier were the not a guaranteed life. They were a MAX life. IF the engine made to that number of hours without being pulled for some sort of problem (excessive oil consumption, low compression, metal bits in the oil, etc) the Manufacturer strongly recommended pulling the engine for overhaul regardless of how well it was running. In the early part of the war it was quite common to order 50% more engines than the number of single engine airframes in order to allow for a good supply of spare engines/parts. If engines lasted for 1500 hours why bother to do that?

I would note that even in transport service it took until after WW II for engines to get approved for over 1000 hours.
Pre war there were some DC-3s that had gone through 12 sets of engines in just 4-5 years.

Please not I am not claiming the Merlin was the equal of the Allison in regards to strength or durability.
I am questioning the use of a particular type of engine failure as a measuring stick for overall engine durability/life. There are plenty of other ways for an engine to fail (in sometimes spectacular fashion) aside from bearing failure.

The point that I was trying to make was that the expected engine life far exceeds the average life expectancy of the aircraft using the engine. I.E. If the average fighter survives for 100 three hour flights then why do you need an engine for it that lasts five times as long, surely it would be better to use them as the Soviets did.

 

[Shortround6]

In actual fact the airframe's life far exceeded the average life of the engine's, which is why they not only provided a large percentage of extra engines but established repair/overhaul facilities is different theaters. For the Merlin there were 4 facilities in Great Britain doing overhaul work and overseas there were two on India, one in Egypt and one in Algiers. Just in the UK and not counting the Royal Navy, 50,000 Merlins were repaired/overhauled and returned to service or place in store.
The US got in serious trouble in North Africa with the P-40F because they only allocated 20% extra spare engines and what with the dirt/sand in North Africa they were going through engines much faster than planned. The British (it may have taken a while) broke down up to 600 used Merlins in that Theater to provide the US Forces with parts to repair/over haul the engines for the P-40Fs.

This is totally at odds with your statements about 1500 hour Allison life and 500 to 600 Merlin engine life.
Once again, average time between a particular type of failure is NOT engine life.

 

[Shortround6]

From one website explaining mean time between failure. (MTBF)

"MTBF is usually applied to a group of similar equipment, for example all the pumps in a refinery. The formula for this is (NUMBER OF PIECES OF EQUIPMENT X TIME PERIOD) / NUMBER OF FAILURES DURING THAT TIME
Example:
1200 Pumps over one year with a total of 387 failures during the year.

(1200 X 12(months))/ 387 = 37 months MTBF

 

[Schweik]

Schweik, you mentioned something about japan not intending to invade northern Australia. That's not entirely correct.

This is a link to some source material that you may find interesting

Battle for Australia: Japanese debate Invasion of Australia

I'm aware of the plan, but they had apparently ruled it out - the Navy was for it but the Army against. I mentioned it in another Thread in fact and kind of got jumped on over it.

I do think the Australians had a very legitimate reason to be worried about an invasion.

I do think the Japanese considered it and might have actually done a partial invasion under the right circumstances. We were looking at Townsville as a target in the other thread.

But it also seems clear historically that the Japanese decided against it. No doubt helped by the strong push back they faced in New Guinea and the Solomons.

Per the context of my mentioning it in this thread, I do think the raids on Darwin were basically harassment raids which is why they bombed from 27,000 ft. If they were closer to an actual invasion I think the bombing would have been more intense, on a much larger scale and pressed home a lot more aggressively.

S

 

[Shortround6]

According to "Vees for Victory" the US ordered 730 Allison C-15 engines to support 534 P-40 fighters. this contract was changed at a later date. A later contract was for 334 engines to be installed in the P-40B & C with and additional 113 to be held as spares.
Initial "life" of the C-15 engine was 150 hours but after doing initial overhauls Allison recommended extending that to 200 hours for a batch of ten engines with further extensions of "life" based on results (wear) of these overhauls. Life eventually hit 400 hours but I don't know if that is for the C-15 model or some later models. This section of the book doesn't say. Some very late models did run around 1000 hours in training aircraft.(from another chapter)

For the C-15 engines the British took delivery of 1770 engines with 100 (or 150?) sent to China (AVG) for 1180 Tomahawks and 143 twin engine P-322s (most of which stayed in the US).

 

[RCAFson]

Yeah I mistyped that initially and went back to correct.

So it sounds like they did continue development on the Hurricane, at least to some extent.

Since you are the resident expert on the Hurricane can you break down performance (max level speed, ceiling, climb rate, Hp, max boost, dive speed, critical altitude etc.) for the various subtypes?

Mk 1
Mk IIa
Mk IIb
Mk II (Russian Field Mod)
Mk IV
Mk XX
Mk XI
Mk XII
Mk XIIa

And max roll rate if you know or care to estimate ?

This is a summary of Boscombe Down test results of individual aircraft:
View attachment 498350
(From Mason, The Secret Years)

Engine performance and boost levels varied by year according to Rolls Royce certifying the boost level so it's not possible to break it down by aircraft mod. Merlin III combat boost was 12lb from early 1940 onward. Sea Hurricane Merlin III 16lb boost was from mid 1941 onward. Merlin XX was 12lb from Dec 1940 onward until late 1942 when 14/16b boost was allowed. Merlin 45 was ~16lb from Jan 1942 onward. See Lovesey, Figure 24, for more info:
http://www.wwiiaircraftperformance.org/merlin-lovesey.pdf

some more data on Hurricane Mk 1-V:

K5083 - Technical Data
(mostly accurate)

 

[Stig1207]

Supposedly, 11500 claims and 10410 confirmed, Hurricane got 55%, Spitfire 33%. I know what you're getting at, its rather high for the 1939/41 period and maybe even a handful in 1942. My guess would be halve the number confirmed. It includes Battle of France, Dunkirk, Battle of Britain, the Blitz, Dieppe plus any other minor ops. It must be at least 2000 for everything excluding Dieppe and other minor ops.

Victory claims / credits that I have been able to find by Hurricanes in the ETO amount to '41= 173½; '42= 45 and ' 43 none.
I would think that the Hurricane would have a couple of thousand claims up until the end of '40; but that still leaves a few thousand unaccounted for?

 

[RCAFson]

Here's a summary of Boscombe Down Hurricane and P-40 test results:

 

[Schweik]

Victory claims / credits that I have been able to find by Hurricanes in the ETO amount to '41= 173½; '42= 45 and ' 43 none.
I would think that the Hurricane would have a couple of thousand claims up until the end of '40; but that still leaves a few thousand unaccounted for?

They must have had at least a couple of hundred claims in the Med, probably the same in Russia and CBI. Would love to see the total numbers.

 

[Kevin J]

They must have had at least a couple of hundred claims in the Med, probably the same in Russia and CBI. Would love to see the total numbers.

My guess would be at least several hundred in the Med, maybe more. The Hurricane was superior to most Italian fighters, and when operated at 2000 to 3000 metres, the Hurricane II with boost was comparable in performance to the Mc 202 Folgore in 1942.

 

[Schweik]

My guess would be at least several hundred in the Med, maybe more. The Hurricane was superior to most Italian fighters, and when operated at 2000 to 3000 metres, the Hurricane II with boost was comparable in performance to the Mc 202 Folgore in 1942.

I can tell you that Hurricanes did not score a lot of air to air victories in 1942, per Christopher Shores records. They racked up a few before the Bf 109 showed up. I don't think they fared well against MC 202s either.

We can dive into it a bit if you want I have the books handy.

I think most of the Hurricane victories in the Med were in 1941 and against Italian G.50 and MC.200, German Bf 110 (which came before the Bf 109s did), German and Italian bombers, and Vichy French types. They did get some kills of Bf 109E too but by the time the 109F got there the Hurricanes seem to have been focusing on bombing or sometimes attacking bombers.

S

 

[Kevin J]

I can tell you that Hurricanes did not score a lot of air to air victories in 1942, per Christopher Shores records. They racked up a few before the Bf 109 showed up. I don't think they fared well against MC 202s either.

We can dive into it a bit if you want I have the books handy.

I think most of the Hurricane victories in the Med were in 1941 and against Italian G.50 and MC.200, German Bf 110 (which came before the Bf 109s did), German and Italian bombers, and Vichy French types. They did get some kills of Bf 109E too but by the time the 109F got there the Hurricanes seem to have been focusing on bombing or sometimes attacking bombers.

S

I'm sure you're right for 1941. I'm just quoting Eric Brown who thought the Hurricane should beat the Folgore in a dogfight. I'd be interested in seeing the figures if you have them. The (Sea) Hurricane would have fought many battles in 1941/42; Western Desert, Greece, Crete, Syria, Malta, the Malta convoys, Operation Torch and of course over Yugoslavia. By the end of 1942, replacement with Tomahawks, Kittyhawks and Spitfires, was I'm sure the right move.

 

[Schweik]

I'm sure you're right for 1941. I'm just quoting Eric Brown who thought the Hurricane should beat the Folgore in a dogfight. I'd be interested in seeing the figures if you have them. The (Sea) Hurricane would have fought many battles in 1941/42; Western Desert, Greece, Crete, Syria, Malta, the Malta convoys, Operation Torch and of course over Yugoslavia. By the end of 1942, replacement with Tomahawks, Kittyhawks and Spitfires, was I'm sure the right move.

I don't have overall figures but if you want me to look up any particular battles on specific days I can check that for you. There were certainly a few 'good days' for Hurricanes I can try to find some examples later.

S

 

[Kevin J]

I don't have overall figures but if you want me to look up any particular battles on specific days I can check that for you. There were certainly a few 'good days' for Hurricanes I can try to find some examples later.

S

You'd think the RAF would publish a few more totals, but then the narrative is that the Spitfire was the wonder plane.

 

[Schweik]

With the Desert War, it see-sawed a lot:

at first Gladiators seem to have been doing well vs Cr 42 and misc. Axis planes, 1940 >
then MC 200 and G.50 showed up Gladiators suffered (mid 1940 I think) <
then Hurricanes showed up and the G.50 etc. suffered. (late 1940 and 1941) >>
The Germans sent in Bf 110 but they didn't really tip the scales (winter 1940/41) >
Then the Germans sent in Bf 109E and Hurricane was challenged (but still holding it's own) (spring 1941 ... I think) <
DAF got Tomahwaks (P-40B/C) and Hurricane IIc and the Bf 109E had some bad days (though it basically became even) (Summer 1941) =
Kittyhawk I initially had little impact at first, except that they started bombing with them (winter 41/42). =
Bf 109F and MC 202 showed up in numbers and allies suffered badly. (Spring 42) <<
DAF tactics improved, more planes came in and the situation stabilized. Luftwaffe had a few bad days. (Summer 42) =
Kittyhawk III and the first few Spitfires arrived in mid 1942, Luftwaffe suffers some reverses (Autumn 42) >
More Kitty III, some Kitty II and more Spit Vs. US P-40F and P-38s, and B-24 and B-25s arrive. DAF attacking German airbases (Fall 42) >>
Bf 109G and one squadron of Fw 190 arrives (Winter 42 / 43) DAF suffers a bit <
RAF and US Spitfires arrive (Winter 43) DAF rallies >>
5 US Fighter Groups with P-40F, 1 with Spit V and (3?) with P-38s - Germans back on their heels (Spring 43) >>>
Spit IX arrives spelling doom (Summer 43? I think?) >>>>

 

[Stig1207]

They must have had at least a couple of hundred claims in the Med, probably the same in Russia and CBI. Would love to see the total numbers.

Unless I misunderstood Kevin, the figure of 5871 victory credits (or claims?) awarded Hurricanes was for the ETO only; any other claims/ credits in other theatres would be on top of that. I just can't see how they could get such a large of victories in the ETO?

 

[Kevin J]

Unless I misunderstood Kevin, the figure of 5871 victory credits (or claims?) awarded Hurricanes was for the ETO only; any other claims/ credits in other theatres would be on top of that. I just can't see how they could get such a large of victories in the ETO?

I think you'll find that its awarded victories, but if you look at the awarded victories in 1941/42 for Fighter Command alone they were about four times reality and these were mainly Spitfire claims. From the Battle of France to the end of the Blitz there were about 2000 genuine Hurricane victories then whatever Hurricane victories as close escort and night intruder in 1942 which probably didn't amount to a lot. My guess would be at least an additional 1000 Hurricane victories in the Med from 1940 to 1942, plus maybe another 500 for the Eastern Front and the Far East, but I really don't know. I was just quoting a second hand source from these forums.

 

[Stig1207]

Ahh ok, I was wondering what the source of that number was. However, I don't think you can grant the Hurricanes 2000 'genuine' victories from the BoF to the end of the Blitz either; they would also be awarded victories and subject to overclaiming, though perhaps not 4-5 times overclaiming as in '41-42.

 

[Schweik]

Unless I misunderstood Kevin, the figure of 5871 victory credits (or claims?) awarded Hurricanes was for the ETO only; any other claims/ credits in other theatres would be on top of that. I just can't see how they could get such a large of victories in the ETO?

You have a point. How many planes did the Luftwaffe lose in the BoB anyway?

Per this, ~ 1300 planes lost to all causes.

S

 

[Kevin J]

You have a point. How many planes did the Luftwaffe lose in the BoB anyway?

Per this, ~ 1300 planes lost to all causes.

S

The RAF lost about 1300 of all types, the Luftwaffe about 1800.