Spitfire V Versus P-40E

[Reluctant Poster]

I really don't care if it had warp drive all I care about is that it wasn't a Bendix

I should apologize. That answer was flippant When I see an error I have to correct it, it is my nature.
I do agree that the SU negative problems were solved and that the later Spitfire Vs were much improved. In fact the Seafire III powered by the Merlin 55 was fully competitive to the end of the war.

 

[Schweik]

I really don't care if it had warp drive all I care about is that it wasn't a Bendix

All I care about is did it work.

 

[Schweik]

Against the FW190 the '41 version was outclassed, by '43 the Anton pilot needed to have is brain in gear, what made his job even worse was the Mk IX looked the same except for being 9'' longer, and both had reliable belt fed Hispano's loaded with SAPI rounds.

At 1,500+ HP down low and clipped wings for a superlative roll rate + less drag, Spit LF Mk Vc is pretty dangerous for a 190 I think.

 

[Schweik]

Also going to the belt fed guns meant smaller bulges on the wings which was also less drag

 

[Greyman]

The belt-fed Hispano Spitfire actually heralded the larger bulges of the 'C' wing that were to accommodate the four-cannon option.

Later when it was decided the four-cannon wing was essentially never used -- covers with smaller bulges were manufactured. But to your point I do believe these '43/44 panels were smaller than even the initial '41 panels.

 

[Clayton Magnet]

The Spit V was also a big leap forward

Was it though? The Mk.V was the definitive low point of the Spitfires career, with the Australian Mk.V's (Merlin 46, hastily fit tropical filters, malfunctioning cannons) experience over Darwin being the bottom.
I love the Spitfire, but that configuration seems like almost a worst case scenario.

 

[Schweik]

Was it though? The Mk.V was the definitive low point of the Spitfires career, with the Australian Mk.V's (Merlin 46, hastily fit tropical filters, malfunctioning cannons) experience over Darwin being the bottom.
I love the Spitfire, but that configuration seems like almost a worst case scenario.

They had trouble in Russia too with the Spit V. Clearly it made a bad first impression.

But yeah this is how i see it. Putting cannons in the Spit was a fairly big engineering leap, as was the new engine (IMO). But any time you make significant changes you have an adjustment period. Spit V was kind of rushed into action before the shakeout was done (because it had to be) - and at the end of a very long supply chain all problems get exaggerated. Same thing happened incidentally with the early P-40s, especially the P-40E. They had trouble in the Philippines and Java just getting them flying. The Australians lost like twice as many getting their first batch of Kittyhawks into the combat area as they did in action. There are a lot of little details that have to be sorted out - like what throttle setting to use in combat!

However, as noted, the Spit V was around for a long time. Clearly at some point it became rather more dangerous and effective. I think the big threshold was when the guns became more reliable. In MAW you can see that initially the Spitfire units were maybe suffering a bit but by the end of 1942 it seems like they had sorted a few things out and were taking a toll. As were the later model Kittyhawks.

Darwin was a bit later than that but it was 13,000 km from London. A lot can go wrong across that distance, and did.

 

[Juha3]

They had trouble in Russia too with the Spit V. Clearly it made a bad first impression...

Soviets had their problems but their experiences were not entirely negative. I'm busy now, so only a quote from Spitfires over the Kuban by Igor Zlobin © Tranlsation by James F. Gebhardt ©
(the numbers are showing how the Soviets saw the results, and remember that most Soviets really liked P-39s, 3 of their 5 top scorers got most of their kills while flying Airacobras)

Table 1. Combat work of the 216th SAD from 1–10 May 1943​

Regiment-------Number of aerial---Downed enemy-----Damaged enemy------Soviet losses
-------------------engagements--------aircraft---------------aircraft--------------Destroyed---Aircraft did not---Pilots
---------------------------------------(bombers + fighters)-------------------------aircraft----------return
16 GIAP (P-39)----20-------------------24-(8 + 16)-----------9------------------------1----------------2-------------3
57 GIAP (Spitfire)-23-------------------30-(15 + 15)---------10------------------------4----------------3-------------3
42 GIAP (Yak-1)----2--------------------1----------------------------------------------------------------1--------------1

​

 

[Schweik]

I read the article Spitfires over the Kuban, and I agree it wasn't an unmitigated disaster but nor was it the rousing success they were expecting. Also I think different P-39 units in various regions had rather wildly different rates of success if I remember correctly.

I wouldn't say the Spit V was more successful for the Russians than the Kittyhawk was.

 

[Reluctant Poster]

I read the article Spitfires over the Kuban, and I agree it wasn't an unmitigated disaster but nor was it the rousing success they were expecting. Also I think different P-39 units in various regions had rather wildly different rates of success if I remember correctly.

I wouldn't say the Spit V was more successful for the Russians than the Kittyhawk was.

The Spitfires were refurbished Vb's and they had the higher altitude 46 where a cropped 45 would have been more appropriate

 

[Clayton Magnet]

However, as noted, the Spit V was around for a long time. Clearly at some point it became rather more dangerous and effective

The Mk.V started life a half step behind to begin with. Perhaps in hindsight it was the best available decision to develop the model minus the Merlin XX, but it is more romantic to imagine the Fw 190 like performing Mk.III following the Mk.II into service in 1941.

 

[Kevin J]

The Mk.V started life a half step behind to begin with. Perhaps in hindsight it was the best available decision to develop the model minus the Merlin XX, but it is more romantic to imagine the Fw 190 like performing Mk.III following the Mk.II into service in 1941.

End 1940 we're expecting a German invasion in 1941, we don't know about the Bf 109F nor the Fw 190a. So we needs lots of fast climbing interceptors fast ready for a Summer invasion. The Spitfire Vb means we don't have to change the production lines. It's a quick fix.

 

[Mike Williams]

The standard Merlin 45s were eventually approved for 16lbs boost and either 1515hp at 11,000ft or 1470hp at 9250 depending on exact model and carburetor. The 1200hp figure was at a bit above 18,000ft.

Question on the Spit MK V is when the units in the field went from 9lbs boost to 12lbs and then when they changed from 12 to 15/16lbs boost.

+12 was cleared for take-off from the get go on the Merlin 45. Rating of Merlin RM5S (Merlin 45), January 1941:


Spitfire V Type sheet from July 1941:


Merlin XLV - Operational Limitations, July 1941:

 

[Juha3]

The Spitfires were refurbished Vb's and they had the higher altitude 46 where a cropped 45 would have been more appropriate

At least with 57 GIAP their Spit Vbs were powered by both Merlin 45s and 46s. That most Spit Vbs sent to the USSR had Merlin 46s maybe was one of the main reasons why they ended up serving with the PVO, that also solved the problems related to poor airfield surfaces.

 

[Mike Williams]

This document shows that +16 was approved by January 1942, whereas this report dated Nov. 42 and based on testing taking place from July - Sept. 42 notes "The operational limitations of the Merlin 45 have been increased, the use of 3000 R.P.M. and +16 lb/sq.in. boost being now permitted for periods not exceeding 3 minutes during combat."

 

[Vincenzo]

i suspect that this http://www.wwiiaircraftperformance.org/merlin-ratings_3jan42.jpg is from 3rd january '43

 

[Reluctant Poster]

i suspect that this http://www.wwiiaircraftperformance.org/merlin-ratings_3jan42.jpg is from 3rd january '43

I don't believe so. It states the Merlin 61 is for production in summer 1942.
also it lists the Merlin 30 by 1943 it was replaced by the 32

 

[Mike Williams]

Interestingly this chart for the Merlin 46 & 47 dated 27 March 1942 shows the +12 take off rating as well as the +16 Emergency rating.

These un-dated Operational Notes for Pilots on Merlin 46 Engines show the +12 take-off and climb rating.

 

[Shortround6]

So we basically have Spitfire MK Vs with 3 different armament setups, A number of different engines even if most of them were operated at the same performance levels if allowed to use the same boost. and we can throw in two different wing tips (but only on later Vbs and Vcs, late 1942?)

The P-40E has no change in armament, two possible engines (pre and post Dec 1941) and possible different max boost allowances based on engine (date of manufacture).This last is conjecture on my part, in any case the P-40K took over from the P-40E on the production lines in May of 1942.

Please note that it took months to get US fighters to the war zones. In some cases US fighters, like some/many P-40s, went to British modification centers before being shipped on to final destinations/war zones so first planes out the factory door are months away from first combat.
The first modification center was at the Tomahawk school at Cunliffe-Owen Aircraft which by Nov 1941 was responsible for repairs to RAF Tomahawks, Bristol Blenheims and Lockheed Hudsons. The Kittyhawks were added.
Scottish Aviation at Prestwick also assembled and modified many Kittyhawks and another modification (assembly) center was Air Service Training Center Hamble near Southampton which also worked on early P-39s and Mustangs.

My conjecture comes from Allison changing the crankshaft in the Allison engines in Dec of 1941. The new crankshaft was stronger and much more fatigue resistant. This is what allowed the engines in the P-40Ks to be rated at 1325hp for take-off. I believe that many late build P-40Es may have had these crankshafts.
I don't doubt that the older engines (all -39 engines) could be run at the high boost settings, the question might be for how long or how many times?
Official US approval for WEP settings was around 3/4 of a year after the change in the crankshafts?

NA had built about 138 Mustangs for the British in 1941 and another 84 in both Jan and Feb so how long it took the better crankshafts to work their way through the supply chain and into the Mustang Is I have no idea.


We really have to be careful as to which Spitfire V we are comparing the P-40E or later versions of the P-40.

 

[Shortround6]

Interestingly this chart for the Merlin 46 & 47 dated 27 March 1942 shows the +12 take off rating as well as the +16 Emergency rating.

View attachment 589238

These un-dated Operational Notes for Pilots on Merlin 46 Engines show the +12 take-off and climb rating.

It's a mystery as to why the Australians were operating the Melrin 46s at a 9lb boost limit at the time of the test.