An Allison V-1710 with a two-speed supercharger in 1942 (1 Viewer)

[yulzari]

It is unfortunate that the French Szydlowski-Planiol swirl throttle failed to get advertised in the UK (or proposed by French Air Ministry Services to the UK) in time to integrate it in Merlin supercharger development.
A Merlin 4X with it would have had a lot more leeway to optimize critical altitude without sacrificing too much low-altitude performance, given the greater efficiency of the swirl throttle vs the common butterfly type.

As a piece of trivia: the swirl throttle was part of the Rolls Royce support for the BRM V16 Grand Prix cars. Intended to be used in the next annual update to tame the brutal power curve of the centrifugal supercharger but Formula 1 was all but abandoned in that following year with the world championships being run to the naturally aspirated Formula 2 and development of the 1.5 litre BRM V16 was abandoned.

 

[Steamed_Banana]

Good, progress can be made, the simple comparisons between US fighter groups needs to take into account 1 with Spitfires spending time in the Coastal Air Force and 1 with P-40 in the Strategic Air Force, the date of majority P-38 missions out of Africa was later than stated, the location of 15th Air Force fighter combats was different to stated, the number of Luftwaffe losses was much higher than stated as starters.

Effectiveness of the P-38

I really feel like we are talking past each other, but I'm just going to say this. I'm not trying to change the official score of any particular pilot (the case about Boyington is interesting and worth discussing, but not for the reasons you seem to assign to me) or any particular unit, or...

ww2aircraft.net

the promise in message 380

Insults are a form of engagement, I have been advised to treat the smiley as an insult, though of course we know the strongly opinionated are the ones most likely to laugh at data that does not fit.

Your ludicrous statements and absurd posturing are simply funny, there is no other way to react.

I decided to quit engaging with you, mainly to spare the other readers of the forum having to see pointless exchanges of insults, and to spare myself wasting bandwidth arguing with someone who isn't self aware enough to discuss even technical data honestly or have an adult conversation. But you are now engaged in a campaign of one-sided bashing, which I'm not just going to sit still for.

You write super long posts full of data which is sometimes real, and sometimes just made up. In the latter case you never admit or acknowledge your errors.

Allow me to point out the latest example, you wrote:

When it comes to largely ceasing to engage in air combat the P-40 groups cut off dates were 33rd in September 1943, 57th in April 1943, 79th in June 1943, 324th in July 1943, 325th in August 1943.

and I just posted examples of:

324th FG heavily in engaged in air combat with P-40s in Dec 1943 - Feb 1944
57th FG heavily engaged in air combat with P-40s in Dec 1943 (having partially but not fully converted to P-47s by that point)
79th FG heavily engaged in air combat with P-40s through February 1944
33rd FG heavily engaged in air combat with P-40s through January 1944.

The only one of these claims which was accurate in fact was for 325th FG. And I already posted the correct dates in another post previously upthread.

Nor was this the only error in that long post, you made several, and were very typically highly confident on a topic of which you are clearly out of your depth. But I figured this was one area in which I could contribute some concrete data which is always more useful than opinions.

I've seen several of your posts including valuable data, but you don't distinguish between areas where you know something about the subject and those where you clearly do not. The posturing and ponderous info dumps are laden with errors and you are impervious to learning anything from anyone else when you make them or are corrected. I've never seen you acknowledge being wrong or learning from someone else's posts. This is why I will continue to for the most part ignore what you post. But of course, if you specifically contradict what I'm writing and insult me I will reply accordingly.

 

[Steamed_Banana]

Here is some more fighting earlier in 1943:

(again only counting 'confirmed' claims unless otherwise stated)

7 June 1943
Allied claims: 14 Sqn RAF (Mustang 1) 1 x unidentified float plane, US 57th FG (P-40F) 2 x Bf 109, US 52nd FG (Spitfire V) 1 x Bf 109, US 79th FG (P-40F) 2 x MC 202, US 99th Bomb Group gunners 6 x Bf 109, 1 x Fw 190
Allied losses: 1 x A-36A, 1 x P-38G,
German losses: 4 x Bf 109G-4 and G-6, 1 x Cant Z.506 (1 of the Bf 109s say "combat with B17s" one ssays "damaged by P-40s", the other two unknown.

8 June 1943
Allied claims: US 1st FG (P-38G) 1 x MC 202, US 52nd FG 1 x MC 200, US 79th FG (P-40) 3 x MC 202, 3 x Bf 109
Allied losses: 1 Spitfire V
Axis loses: 2 x MC 205, 3 x MC 202

10 June 1943
Allied claims: 14 Sqn RAF (Marauder I) 1 x SM.82, 2 x Bf 109, 185 Sqn RAF (Spit IX) 1 x MC 202 and 1 x Bf 109, US 31st FG (Spitfire V) 2 x Fw 190, 5 x Bf 109, 6 x MC 202, US 325th FG (P-40F) 5 x Bf 109, US 79th FG (P-40F) 5 x MC 202, 11 x Bf 109
Allied losses: Spitfire X (shot down by P-40s / friendly fire), 3 x P-40s,. 1 x B-26 force landed
Axis losses: 15 x Bf 109G-4 and G-6, 1 x He 46 shot down by ground fire

11 June 1943
Allied claims: 14 Squadron RAF (Marauder 1) 1x Bf 109, US 57nd FG (P-40F) 2 x Bf 109, US 52nd FG (Spitfire V) 1 x Fw 190, US 31st FG (Spit IX) 7 x Bf 109, 4 x Fw 190, US 81st FG (P-39s!!) 3 x Fw 190s
Allied losses: 2 x Spitfire V, 1 x B-26
Axis Losses: 2 x Bf 109G, 3 x Fw 190, 2 x MC 205

8 July 1943
Allied Claims: 72 Sqn RAF (Spit Vc) 2 x Bf 109, 52nd FG (Spitfire) x 1 Ju 88, US 324th FG (P-40F and L) 3 x Bf 109, 350 FG (P-38) 1 x Ju 88
Allied Losses: 3 x P-40, 1 x A-36, 2 x B-17, 2 x B-24
Axis Losses: 5 x Bf 109G-6, 1 x Ju 88T, 1 x Bf 109G (Italian)

9 July 1943
Allied Claims: 185 Sqn RAF (Spit IX) MC 202, Fw 190, 32 Sqn RAF (Spit Vc) Bf 109, 324th FG (P-40F/L) 10 x Bf 109, 14th FG (P-38G 2 x Bf 109, A-20 gunners 2 x Bf 109, 2 x Fw 190, B-17 gunners 1 x Bf 109
Allied Losses: 4 x Baltimore III, 5 x P-40s, 1 x P-38, 1 x A-36, 3 x A-20, 1 x B-24
Axis Losses: 1 x Bf 109, 1 x Bf 109 (Italian)
(this was an interesting one because part of the 324th FG mission here was to escort A-36s. But they took heavy losses and very little to show for it)

22 July 1943
Allied Claims: 272 (Beaufighter VII) 1 x Do 18, 325th FG (P-40F/L), 2 x Bf 109, 9 x MC 202, 2 x Ju 52, 2 x Fi 156, 82 FG (P-38G) 2 x Bf 109, B-17F gunners 8 x Bf 109, 1 x Re 2001
Allied Losses: 3 x P-40L, 1 x B-17
Axis Losses: 3 x Ju 51, 2 x Fi 156, 5 x MC 205, 2 x MC 202, 1x D.520, 1 x Ca 309, 1 x SM. 81
(interesting that a D.520 wwas engaged here)

26 July 1943
Allied Claims: 52nd Sqn RAF (Baltimore IIIa) 1 x SM 82, 144 Sqn RAF (Beaufighter LX) 2 x Me 323, US 325th FG (P-40F/L) 4 x MC 202, 1 x Bf 109
Allied Losses: 1 x Spit IX, 1 x Baltimore IIA, 1 x Beaufighter X, 1 x Beaufighter VI (US)
Axis losses: 3 x Bf 109G, 2 x Me 2323, 1 x He 46, 2 x Mc 205, 1 x SM 82

30 July 1943
Allied Claims: 52 Sqn RAF (Baltimore IIIa) probable Ju 52, 14 Sqn RAF (Marauder I) Me 323, 272 Sqn RAF (Beaufighter VI) 2 x He 115, 5 x Do 18, US 52nd FG (Spit IX) 2 x Fw 190, US 325th FG (P-40F/L) 21 x Bf 109, US 82nd FG (P-38) 1 x P-38
Allied losses: 1 x P-40L
Axis losses: 6 x Bf 109G-6 lost, 2 x Ju 88A-4 lost, 1 x Ju 52/3m, 1 x Me 323, 2 x MC 202 "damaged in combat", 2 x Cant Z.506 FTR
(325th FG overclaimed a lot here but clearly won a very lopsided victory. It's interesting how the Allied bombers keep going after the Axis transports. Z.506 is a floatplane which looks a bit similar to he 115 or Do 18)

7 August 1943
Allied Claims: 81 Sqn RAF (Spit IX and Vc) 1 x twin engined aircraft, US 325th FG (P-40) 2 x Bf 109, US 82nd FG (P-38G) 2 x Fw 190
Allied Losses: 1 x P-38G, 1 x B-26, 3 x B-25
Axis Losses: 3 x BF 109 G-6 lost (1 to P-40, 1 to flak), 1 Cant Z.506 FTR

 

[Howard Gibson]

I could be way-off but my own 'theory' is that the Merlin XX solved a problem that somewhat went way when better fuel showed up. So we have to very careful about dates, boost limits and altitudes.
In 1940 with limits of 9lbs (or so) boost the two speed supercharger offered a lot more power at lower altitudes and just enough to say so at around 17,000ft and above.
When they got 12lbs of boost the difference was almost the same but when you get to the 15-18lb area the lines get somewhat blurrier. Do we really want to argue about 1470hp at 9250ft at 16lbs from a Merlin 55 compared to 1510hp at 9250ft at 18lbs from a Merlin 24/25? Yes the 2 speed engine is good for1635hp low down at 2250ft using 18llbs of boost.

The Merlin X gave about 22.7% more power for take-off/low altitude than the Merlin III engine at 6lbs on 87 octane fuel.
Merlin XX gave about 8.0% more power for take-off/low altitude than the Merlin 45 engine at 12lbs on 100 octane fuel.
Merlin XX series engines (22 and above) made more power than the later Merlin 45 series engines (using standard impellers) but at 16-18lbs of boost the difference may have been in that under 10% range.
The Spitfire with it's low weight could afford the drop in power better than most other Merlin powered aircraft.
Most all later Merlins were limited to 9lbs of boost and 2850rpm for climbing in non-emergency conditions no matter what the combat limits were.

A supercharger uses engine power to maintain manifold boost. If you have a two-speed supercharger, as just about everyone did late in the war, you use less engine power to drive the supercharger at low altitude. That is extra power to the propeller, where you want it, at low altitude. So much engineering is a compromise.

Spitfire_Vs, and many of the Merlin Seafires single speed superchargers. They selected speeds at which the aircraft would have good performance, and they wrote off everything else.

 

[Steamed_Banana]

So it seems like the main effect of a Merlin XX for the Spitfire would be the elimination of the need for the LF variants

 

[Geoffrey Sinclair]

Your ludicrous statements and absurd posturing are simply funny, there is no other way to react.

A no effort fact free editorial inviting people to ignore the information, which both relies on an defines the reputation of the person making the editorial.

To be followed by lots of accusations about the bad guy and claims of good intentions to everyone else.

You write super long posts full of data which is sometimes real, and sometimes just made up. In the latter case you never admit or acknowledge your errors.

When it comes to data accuracy plenty of people are able and willing to point out errors, like mine about Merlin altitude ratings, or at least query the data, if someone is continually posting bad data expect lots of corrections, moving on to ignoring the messages as not worth the time to read or reply to. It is more than a single person's opinion. Part of places like this is removing the various inaccurate stories/impressions we all pick up.

Repeating myself. When it comes to largely ceasing to engage in air combat the P-40 groups cut off dates were 33rd in September 1943, 57th in April 1943, 79th in June 1943, 324th in July 1943, 325th in August 1943.

and I just posted examples of:

324th FG heavily in engaged in air combat with P-40s in Dec 1943 - Feb 1944
57th FG heavily engaged in air combat with P-40s in Dec 1943 (having partially but not fully converted to P-47s by that point)
79th FG heavily engaged in air combat with P-40s through February 1944
33rd FG heavily engaged in air combat with P-40s through January 1944.

The only one of these claims which was accurate in fact was for 325th FG.

For my statement "largely" to be incorrect means either most to a solid minority of the air combat claims need to have been made after the given dates or Largely is redefined as Totally. The withdrawal of the Luftwaffe and the switch to mainly fighter bomber operations reduced the chances of P-40 units engaging in air combat. What does heavily mean?

I've seen several of your posts including valuable data, but you don't distinguish between areas where you know something about the subject and those where you clearly do not.

Please provide the list of what subjects I am supposed to know something, which usually tells more about the person making the list.

This is why I will continue to for the most part ignore what you post.

Good, progress can be made by everyone else, the simple comparisons between US fighter groups needs to take into account 1 with Spitfires spending time in the Coastal Air Force and 1 with P-40 in the Strategic Air Force, the date of majority P-38 missions out of Africa was later than stated, the location of 15th Air Force fighter combats was different to stated, the number of Luftwaffe losses was much higher than stated as starters.

But of course, if you specifically contradict what I'm writing and insult me I will reply accordingly.

That comes across as do not contradict the truth bringer, is that classified as an insult?

Luftwaffe lost 711 aircraft in 1943, 246 fighters (13% of German global fighter inventory)

Make the connections, after listing large numbers of USAAF fighter claims and noting they were mostly for enemy fighters, so few enemy fighters actually lost says trying to figure out the better USAAF fighters should really become why were a collective near failure, disguising this by massive over claiming, or the enemy losses figures are incorrect instead more like the ones in Williamson Murray.

 

[tomo pauk]

So it seems like the main effect of a Merlin XX for the Spitfire would be the elimination of the need for the LF variants

Plus, if installed on something like the Spitfire II instead of the Merlin XX, it would've gave the RAF a 370+ mph fighter already in the closing stages of the BoB; the Merlin 45 was only available after 1940.

 

[Steamed_Banana]

A no effort fact free editorial inviting people to ignore the information, which both relies on an defines the reputation of the person making the editorial.

To be followed by lots of accusations about the bad guy and claims of good intentions to everyone else.

When it comes to data accuracy plenty of people are able and willing to point out errors, like mine about Merlin altitude ratings, or at least query the data, if someone is continually posting bad data expect lots of corrections, moving on to ignoring the messages as not worth the time to read or reply to. It is more than a single person's opinion. Part of places like this is removing the various inaccurate stories/impressions we all pick up.

You are really describing yourself, and you are editorializing here. You didn't merely challenge data, which is fine, but veered heavily into childish and gratuitous insults layered on top of (incorrect) claims on the data, to which I responded. You apparently want to go on forever trading insults but I'll limit my engagement to the bare minimum. Everything I said about you holds true and I think it's obvious to most reading the thread.

Repeating myself. When it comes to largely ceasing to engage in air combat the P-40 groups cut off dates were 33rd in September 1943, 57th in April 1943, 79th in June 1943, 324th in July 1943, 325th in August 1943.


For my statement "largely" to be incorrect means either most to a solid minority of the air combat claims need to have been made after the given dates or Largely is redefined as Totally. The withdrawal of the Luftwaffe and the switch to mainly fighter bomber operations reduced the chances of P-40 units engaging in air combat. What does heavily mean?

It means you pulled these statements out of your arse (most likely repeating from some other summary in a secondary source), with no statistics to back up your claims. Several of these groups continued to be involved in intense combat through Anzio as I already pointed out. Just in the 10 days I posted operational data for - admittedly days when I found combat for these units- if I'm counting correctly (correct me if I'm wrong) US P-40 units claimed 51 enemy fighters, for 12 operational losses. Most of these were by the 79th FG alone which claimed 33 enemy fighters, while 33rd FG claimed 13. How many fighter claims do you think were typical for a given fighter group in ten days of combat?

Air to air combat for all Allied fighter units in the MTO waxed and waned during 1943 and 1944, peaking during major operations such as the battle of Kasserine Pass (Feb 43), the battle for Tunisia (through May 43), capture of Pantelleria (June 43), the invasion of Sicily (July-Aug 43), the capture of Corsica (Sept-Oct 43) and Sardinia* (Aug-Sept 43), the invasion of Italy and capture of Naples (Sept 43) and the battle of Anzio (Jan-Jun 44). Between these peaks there were lulls where air to air combat diminished, basically for all Allied fighter groups, the only exception being the P-38 units flying long range escort missions for the B-17s and B-24s. The rest of the time P-40 units were mostly flying fighter-bomber sorties, but as soon as the Axis fighters showed up they were engaged with them again. Often on their own due to their longer range than the Spit V and IX, and the use of the P-38s in other types of missions (more Strategic).

* Before I get corrected as a 'gotcha', Corsica was annexed by Free French, Sardinia by Italians taking over after the Germans withdrew to Corsica, then taken by Allies

You provided zero backup for your claims, but are doubling down on it anyway. Which isn't surprising. But to prove you wrong in detail I would have to count up all the claims for each fighter group across 2-3 years. However, I don't need to do all that.

The total number of claims with P-40s by US and Free French units in the MTO are as follows:

33rd FG (3 squadrons, 137 victories, Nov 42 - Feb 44)
57th FG (3 squadrons*, 144 victories, Aug 42 - Jan 44)
325th FG (3 squadrons, 133 victories, Apr 43 - Oct 43 )
324th FG (3 squadrons, 66 victories, March 43 - July 44)
79th FG (3 squadrons, 118 victories, Dec 42 - March 44)
99th FS (1 squadron / independent - Tuskegee, 17 victories, June 43 - June 44)
Free French GC II/5 (2 squadrons, 8 P-40 victories according to this, July 43- Sept 43)

So given that 79th FG claimed 118 'confirmed' victories with P-40s during their entire deployment in the MTO, and more than 33 of these (27% of their total claims) were claimed during the battle of Anzio in 1944, would you still insist that your claim that they were 'largely' done with air combat by June 1943 is correct? Similarly, 33rd FG claimed 137 victories in 16 months of fighting with P-40s, of which more than 13 were claimed during Anzio in one month (January) in 1944, which is 9%. But they were 'largely ceasing to engage in air combat' by September 1943? Are you sure about that?

I would argue that these facts alone already prove you wrong for those two units. If I thought there was need or enough interest by others here in the rest of the data I would go through the entire histories and count up all the claims for each unit, but that would take days and I doubt very seriously you would admit you were wrong even then, so what is the point?

Make the connections, after listing large numbers of USAAF fighter claims and noting they were mostly for enemy fighters, so few enemy fighters actually lost says trying to figure out the better USAAF fighters should really become why were a collective near failure, disguising this by massive over claiming, or the enemy losses figures are incorrect instead more like the ones in Williamson Murray.

There was a great deal of overclaiming, clearly, in the realm of 2-1 to as much as 4-1 depending on the battle (larger air battles tended to result in higher rates of overclaiming, by both Allies and Axis pilots, and not intentionally or as a 'disguise', but due to Fog of War as most people here are well aware). But the US P-40 units were mostly fighting against enemy fighters, with a few exceptions such as the well known 'massacre' of Ju 52 transports and occasional interceptions of large numbers of Ju 88s. The stats from the unit history of the 325th FG which is what I posted are a typical pattern (95 Bf 109 and 26 MC 202 claimed out of a total of 133 claims with the P-40). You can see pretty clearly in the operational history summaries I posted that most of their claims were against fighters, because this is how they were being used, and because the Germans and Italians were not flying many bomber Sorties during 1943 and 44, with a few brief exceptions such as during Kasserine and the landings at Sicily, but were mostly engaged in defensive combat against Allied bombing.

One other key factor is that the Germans had switched from using bombers like the Ju 87 and Ju 88 to using Fw 190s and even Bf 109s as Jabos, several of which were in fact shot down by P-40s (as well as by Spitfires in larger numbers).

 

[Steamed_Banana]

Plus, if installed on something like the Spitfire II instead of the Merlin XX, it would've gave the RAF a 370+ mph fighter already in the closing stages of the BoB; the Merlin 45 was only available after 1940.

And it sounds like a 400 mph fighter in the MTO by mid 1942 or early 43 (whenever the better fuel arrived), or is that not correct?

 

[Steamed_Banana]

One other clarification - IIRC the only one of these five FG which was flying 'Strategic' missions was 325th FG which was attached to a bomber group flying B-26s, and this was for example where they were often engaged over Sardinia with no other friendly fighters around, making it easier to verify their claims. Whether this is really 'Strategic' bombing is debatable, it's a matter of semantics but I'd call it Operational. Similarly some Spitfire units were not flying "coastal patrol" with rare enemy encounters only with long range coastal aircraft like some of the P-39 units or the Beaufighters, but rather were engaged at certain points in protecting Allied shipping during the invasions. So they saw plenty of combat.

 

[Steamed_Banana]

Please provide the list of what subjects I am supposed to know something, which usually tells more about the person making the list.

By the way, you clearly do know a lot about some subjects, I have seen some of your posts which were full of useful information. But you also just as clearly sometimes veer well beyond your areas of expertise, seemingly caught up in anger or nationalistic fervor or other reasons I can't imagine, and attempt to play games to win perceived contests that nobody else is necessarily even competing in. I encourage you to let that go, admit where you don't know all about a given subject, because none of us know all of it. I believe you'll enjoy the experience here more, and the rest of us certainly will.

 

[Howard Gibson]

And it sounds like a 400 mph fighter in the MTO by mid 1942 or early 43 (whenever the better fuel arrived), or is that not correct?

A Spitfire mark VII, VIII, IX, or XVI with two-stage supercharger exceeds 400mph at around 26000ft. This is well above the critical altitude of most single-stage superchargers. A Spitfire XII with an single-stage Griffon engine could not quite hit 400mph at 18,000ft. It was very fast at low altitude.

A Spitfire_III with a Merlin_XX would have a top speed at altitude similar to or perhaps a bit better than that of a Spitfire_V. It would be way better at low altitude.

The effect of high octane fuel is to allow higher manifold boosts. This causes a reduction in the critical altitude at which the supercharger cannot maintain the boost. The top speed listed in the handbooks will increase very slightly. You will see significantly improved performance down below the critical altitude.

 

[Frog]

You are really describing yourself, and you are editorializing here. You didn't merely challenge data, which is fine, but veered heavily into childish and gratuitous insults layered on top of (incorrect) claims on the data, to which I responded. You apparently want to go on forever trading insults but I'll limit my engagement to the bare minimum. Everything I said about you holds true and I think it's obvious to most reading the thread.



It means you pulled these statements out of your arse (most likely repeating from some other summary in a secondary source), with no statistics to back up your claims. Several of these groups continued to be involved in intense combat through Anzio as I already pointed out. Just in the 10 days I posted operational data for - admittedly days when I found combat for these units- if I'm counting correctly (correct me if I'm wrong) US P-40 units claimed 51 enemy fighters, for 12 operational losses. Most of these were by the 79th FG alone which claimed 33 enemy fighters, while 33rd FG claimed 13. How many fighter claims do you think were typical for a given fighter group in ten days of combat?

Air to air combat for all Allied fighter units in the MTO waxed and waned during 1943 and 1944, peaking during major operations such as the battle of Kasserine Pass (Feb 43), the battle for Tunisia (through May 43), capture of Pantelleria (June 43), the invasion of Sicily (July-Aug 43), the capture of Corsica (Sept-Oct 43) and Sardinia* (Aug-Sept 43), the invasion of Italy and capture of Naples (Sept 43) and the battle of Anzio (Jan-Jun 44). Between these peaks there were lulls where air to air combat diminished, basically for all Allied fighter groups, the only exception being the P-38 units flying long range escort missions for the B-17s and B-24s. The rest of the time P-40 units were mostly flying fighter-bomber sorties, but as soon as the Axis fighters showed up they were engaged with them again. Often on their own due to their longer range than the Spit V and IX, and the use of the P-38s in other types of missions (more Strategic).

* Before I get corrected as a 'gotcha', Corsica was annexed by Free French, Sardinia by Italians taking over after the Germans withdrew to Corsica, then taken by Allies

You provided zero backup for your claims, but are doubling down on it anyway. Which isn't surprising. But to prove you wrong in detail I would have to count up all the claims for each fighter group across 2-3 years. However, I don't need to do all that.

The total number of claims with P-40s by US and Free French units in the MTO are as follows:

33rd FG (3 squadrons, 137 victories, Nov 42 - Feb 44)
57th FG (3 squadrons*, 144 victories, Aug 42 - Jan 44)
325th FG (3 squadrons, 133 victories, Apr 43 - Oct 43 )
324th FG (3 squadrons, 66 victories, March 43 - July 44)
79th FG (3 squadrons, 118 victories, Dec 42 - March 44)
99th FS (1 squadron / independent - Tuskegee, 17 victories, June 43 - June 44)
Free French GC II/5 (2 squadrons, 8 P-40 victories according to this, July 43- Sept 43)

So given that 79th FG claimed 118 'confirmed' victories with P-40s during their entire deployment in the MTO, and more than 33 of these (27% of their total claims) were claimed during the battle of Anzio in 1944, would you still insist that your claim that they were 'largely' done with air combat by June 1943 is correct? Similarly, 33rd FG claimed 137 victories in 16 months of fighting with P-40s, of which more than 13 were claimed during Anzio in one month (January) in 1944, which is 9%. But they were 'largely ceasing to engage in air combat' by September 1943? Are you sure about that?

I would argue that these facts alone already prove you wrong for those two units. If I thought there was need or enough interest by others here in the rest of the data I would go through the entire histories and count up all the claims for each unit, but that would take days and I doubt very seriously you would admit you were wrong even then, so what is the point?



There was a great deal of overclaiming, clearly, in the realm of 2-1 to as much as 4-1 depending on the battle (larger air battles tended to result in higher rates of overclaiming, by both Allies and Axis pilots, and not intentionally or as a 'disguise', but due to Fog of War as most people here are well aware). But the US P-40 units were mostly fighting against enemy fighters, with a few exceptions such as the well known 'massacre' of Ju 52 transports and occasional interceptions of large numbers of Ju 88s. The stats from the unit history of the 325th FG which is what I posted are a typical pattern (95 Bf 109 and 26 MC 202 claimed out of a total of 133 claims with the P-40). You can see pretty clearly in the operational history summaries I posted that most of their claims were against fighters, because this is how they were being used, and because the Germans and Italians were not flying many bomber Sorties during 1943 and 44, with a few brief exceptions such as during Kasserine and the landings at Sicily, but were mostly engaged in defensive combat against Allied bombing.

One other key factor is that the Germans had switched from using bombers like the Ju 87 and Ju 88 to using Fw 190s and even Bf 109s as Jabos, several of which were in fact shot down by P-40s (as well as by Spitfires in larger numbers).

My two c :
GC II/5 was a former Vichy unit and not a Free French unit.
In fact two of its Vichyst pilots deserted to join occupied France in 1943 and crashed landed thier P-40F on the Sète beach.

And as to the liberation of Corsica : this was not done by the Free French that officially had ceased to exist by august 1st, 1943, the Free French Forces having been merged with the ex-Vichy Army of Africa followed by the adoption of the official term : Armée Française de la Libération.

 

[tomo pauk]

And it sounds like a 400 mph fighter in the MTO by mid 1942 or early 43 (whenever the better fuel arrived), or is that not correct?

If it is either:
- A Spitfire III airframe (= cut the drag a lot)
- It has in the nose the 2-stage Merlin or the engine of similar power (=much increased power at all altitudes)
then it should beat 400 mph mark

As we know, the Spitfire V even with the best boost and best fit & finish was still under 380 mph.

 

[Shortround6]

So it seems like the main effect of a Merlin XX for the Spitfire would be the elimination of the need for the LF variants

Merlin and Spitfire history is a bit more complicated.
It is also complicated by the demand for two speed engines by other aircraft, Hurricane gets the blame most of the time, but the Defiant and Halifax seem to get overlooked as do the Beaufighter and the Wellington (and the Whitley?)
Of the British factories that built Merlins, Derby built just about all versions. Derby was design headquarters and sometimes just built small numbers of some models. Crewe was the 1st satellite factory and also built most versions. Glascow and Ford came in bit later and were set up to build 2 speed engines from the start. Derby's ability to build two speed engines in large quantities is subject to question.
Both Ford and Glasgow don't start turning out finished engines until sometime in 1941. When they do, they soon are making hundreds of engines a month instead of dozen of engines like Derby. Derby is making a lot more different models per month.
The Merlin 45, 46, 47, 50, and 55 (and the XIII, 30 and 32 built in Derby) were all built by Derby and Crewe.
Most of the two stage engines were built at Derby and Crew.

Trying to maximize each factory's production with the minimum amount of re-tooling/retraining seems to have been the goal.

The Spitfire MK II is also overlooked. The Merlin XII engine was a better engine than the Merlin III with the same 9.09 supercharger gear later used on the Merlin 45 and also used pressure water/glycol cooling instead of pure glycol like the Merlin III. In the summer of 1940 it was allowed to use 9lbs of boost 'normal' with 100 octane and 12lbs boost emergency.
It was also allowed to use 9lbs while climbing and 7lbs at max cruise. Granted the BoB was pretty much over before very many had been delivered but the situation in Aug/Sept 1940 was not Spitfire Is vs Spitfire IIIs with Merlin XX engines and making Hurricanes with Merlin XII engines but was the historical Spitfire IIs vs Hurricane IIS with Merlin XX engines.
British didn't know how badly the Germans had been hurt or perhaps more accurately, they didn't know the Germans ability to sustain losses. The British needed lots of fighters and so they needed better Hurricanes to make up numbers. Germans then screwed up the British by coming out with the 109F instead of just sticking a better engine in 109E the upgraded Hurricane was no longer a good solution.
Merlin 45 had a lot more in common with the Merlin XII than it did with Merlin III.

British took a while to go higher boost levels. The Merlin 45 was introduced at the same 9lb/12lb limits as the Merlin XII but the better supercharger allowed for higher altitudes.
Later they could use 12lbs under more conditions and later they got to use 15/16lbs of boost but that was not until Jan 1942 (?)
Use of the higher boost gained around 25-30mph at around 10,000ft.
Use of a two speed engine in the Spitfire would have been very good idea in late 1940 IF the engines had been available without shorting some other aircraft production.
In 1942 they had gotten a lot better performance out of the single speed engines. A two speed would have been better, but the margin of difference would be smaller.

 

[Steamed_Banana]

My two c :
GC II/5 was a former Vichy unit and not a Free French unit.
In fact two of its Vichyst pilots deserted to join occupied France in 1943 and crashed landed thier P-40F on the Sète beach.

I am aware of that incident, but in the US perspective once converted this is designated as a "Free French" unit from my understanding, individual betrayals notwithstanding.

And as to the liberation of Corsica : this was not done by the Free French that officially had ceased to exist by august 1st, 1943, the Free French Forces having been merged with the ex-Vichy Army of Africa followed by the adoption of the official term : Armée Française de la Libération.

French Army of Liberation = Free French for the Americans, as in "on our side now" = Free French, at least informally, regardless of the previous history of each individual unit or soldier

 

[Steamed_Banana]

If it is either:
- A Spitfire III airframe (= cut the drag a lot)
- It has in the nose the 2-stage Merlin or the engine of similar power (=much increased power at all altitudes)
then it should beat 400 mph mark

As we know, the Spitfire V even with the best boost and best fit & finish was still under 380 mph.

Well there was considerable difference between Spit V airframes vis a vis drag, which is a point that is often overlooked, but I see your point.

 

[Steamed_Banana]

Merlin and Spitfire history is a bit more complicated.
It is also complicated by the demand for two speed engines by other aircraft, Hurricane gets the blame most of the time, but the Defiant and Halifax seem to get overlooked as do the Beaufighter and the Wellington (and the Whitley?)
Of the British factories that built Merlins, Derby built just about all versions. Derby was design headquarters and sometimes just built small numbers of some models. Crewe was the 1st satellite factory and also built most versions. Glascow and Ford came in bit later and were set up to build 2 speed engines from the start. Derby's ability to build two speed engines in large quantities is subject to question.
Both Ford and Glasgow don't start turning out finished engines until sometime in 1941. When they do, they soon are making hundreds of engines a month instead of dozen of engines like Derby. Derby is making a lot more different models per month.
The Merlin 45, 46, 47, 50, and 55 (and the XIII, 30 and 32 built in Derby) were all built by Derby and Crewe.
Most of the two stage engines were built at Derby and Crew.

Trying to maximize each factory's production with the minimum amount of re-tooling/retraining seems to have been the goal.

The Spitfire MK II is also overlooked. The Merlin XII engine was a better engine than the Merlin III with the same 9.09 supercharger gear later used on the Merlin 45 and also used pressure water/glycol cooling instead of pure glycol like the Merlin III. In the summer of 1940 it was allowed to use 9lbs of boost 'normal' with 100 octane and 12lbs boost emergency.
It was also allowed to use 9lbs while climbing and 7lbs at max cruise. Granted the BoB was pretty much over before very many had been delivered but the situation in Aug/Sept 1940 was not Spitfire Is vs Spitfire IIIs with Merlin XX engines and making Hurricanes with Merlin XII engines but was the historical Spitfire IIs vs Hurricane IIS with Merlin XX engines.
British didn't know how badly the Germans had been hurt or perhaps more accurately, they didn't know the Germans ability to sustain losses. The British needed lots of fighters and so they needed better Hurricanes to make up numbers. Germans then screwed up the British by coming out with the 109F instead of just sticking a better engine in 109E the upgraded Hurricane was no longer a good solution.
Merlin 45 had a lot more in common with the Merlin XII than it did with Merlin III.

British took a while to go higher boost levels. The Merlin 45 was introduced at the same 9lb/12lb limits as the Merlin XII but the better supercharger allowed for higher altitudes.
Later they could use 12lbs under more conditions and later they got to use 15/16lbs of boost but that was not until Jan 1942 (?)
Use of the higher boost gained around 25-30mph at around 10,000ft.
Use of a two speed engine in the Spitfire would have been very good idea in late 1940 IF the engines had been available without shorting some other aircraft production.
In 1942 they had gotten a lot better performance out of the single speed engines. A two speed would have been better, but the margin of difference would be smaller.

There is also the issue, as I noted previously, of the ~4,000 Packard Merlin XX / 28 which ended up in Canada and in aircraft which were as far as I've been able to determine mostly not involved in the war. Presumably these could have gone into Spit Vs or P-40s or even P-39s might have been better than Hurricane IIs.

 

[tomo pauk]

Well there was considerable difference between Spit V airframes vis a vis drag, which is a point that is often overlooked, but I see your point.

The best ones were at 370-375 mph. The ones where fit & finish was sloppy were loosing up to 10 mph.
Not good when the LW best are close or at to 400 mph.

 

[Steamed_Banana]

The best ones were at 370-375 mph. The ones where fit & finish was sloppy were loosing up to 10 mph.
Not good when the LW best are close or at to 400 mph.

Well we have issues like

Vokes filter vs Aboukir (15-20 mph?)
bp glass on outside vs inside (3-5 mph?)
Clipped wings (5 mph?)
Fared rear view (1-2 mph)
Malcolm hood (2-4 mph... probably worth keeping even with a speed penalty)
Bomb shackles
Types of antenna
Extra faring for non existent second gun / short second gun stub? (not sure if this was ever even removed)

I think a couple more things that I forgot...

The Germans apparently had a fair bit of trouble with their tropical filters too...