Air combat over Darwin

[Jabberwocky]

Well, there is Air Ministry directive from August 1942 titled "How to make full use of the performance of the Spitfire V, VI IX" which indicates Spitifres since that time were modified to give +16 emergency boost. Author made it clear that this should be known to pilots, and that if used for combat only, there was no risk of engine failure.
I'd be surprised if one, whole year later this would not be known or used by RAAF.

Don't discount just how long it took for information to flow from the UK back to Australia in the mid 1940s. At one point in 1943, the Spitfire maintenance and parts shops in Melbourne were making modifications for the Darwin Spitfire Mk VCs based on mods that were nearly two years out of date.

 

[Hiromachi]

I am aware of that, but there is other part of the story. Many of the 1st Wing Pilots were veterans participating in multiple operations before, much closer to Britain. Thus it is also possible that they were aware of boost changes.

 

[Aozora]

I am aware of that, but there is other part of the story. Many of the 1st Wing Pilots were veterans participating in multiple operations before, much closer to Britain. Thus it is also possible that they were aware of boost changes.

The pilots might have been aware of the boost changes, but that doesn't mean that the Merlin 46s used in Australia had been modified to use the increased boost. The RAAF's Pilot's Notes show +12 lbs boost and papers in the Australian National Archives show that +12 lbs boost was the maximum used (note that the images don't seem to be available for download).

Unless other information can be found, confirming that the RAAF allowed the 1 Wing Spitfire VCs to use +16 lbs, the documents listed are all we have to go on - anything else is speculation.

 

[tomo pauk]

FWIW, this document allows for 60 in Hg (don't know why the US units), ie. +15 psig of boost on Jan 1942. The previous limit was +12 psig (54 in Hg) per this.

Point might be that Merlin 46/47 were not that good under 15000 ft, with supercharget tailored for 20000 ft an above. The Spitfire (or any other defender) still has to climb through this altitude belt, SL to 15000 ft, and that would be a laborous task. One will be ill advised to climb on combat rating, leaving the power of under 1100 HP for such lowere altitudes.

 

[Aozora]

Papers available for downloading from the ANA:

Allotment of Spitfire Squadrons from U.K. (Nos: 452 and 457 RAAF No. 54 RAF).
No 1 (Fighter) Wing] - Tactical appreciation - Spitfire aircraft - Combat reports
Spitfire Aircraft: Gun heating pipe defects.
Aircraft Status cards - Spitfire A58-1 to A58-99

FWIW, this document allows for 60 in Hg (don't know why the US units), ie. +15 psig of boost on Jan 1942. The previous limit was +12 psig (54 in Hg) per this.

These notes would have been for USAAF units using these aircraft types.

 

[parsifal]

I am aware of that, but there is other part of the story. Many of the 1st Wing Pilots were veterans participating in multiple operations before, much closer to Britain. Thus it is also possible that they were aware of boost changes.

The personnel manning 1FW were not experienced according to Coopers "Darwin Wing". It states in Chapter 1 that the squadrons were still largely homogenous in 1942, whilst serving in the ETO. It describes them as "being thorughly average" and "(like) all squadrons were thoroughly typical Fighter Command Squadrons of 1942 with an over abundance of greeen pilots, hastily promoted leaders, and limited operational experience all round". This was made worse when the move to Australia. most of the non-Australian personnel remained in England to be re-assigned, and the the replacements used to fill them were mostly greenhorn pilots straight out of flight school, most having graduated in October 1942. Some of the air leaders drawn from home defence were experienced, but noine of these guys had combat experience, and limited exposure to issues like radar and turbo boost in high performance engines.

54 sqn was ostensibly the most experienced unit, but there was little to get excited about in terms of the experience it brought to battle. The unit had BoB experience, but the current personnel (even in England in 1942) did not, made worse by the greenhorn replacements used to fill the billets vacated by European personnel on redeployment. The original BoB personnel had long since been re-assigned. Of its entire complement, only 3 pilots at the end of 1942 were considered to have any meaningful combat experience. The rest were all green pilots with less than 6 months flying experience. there were one or two exceptions to these two categories. Bill Gibbs, for example was a pre-war RAAF officer, with a lot of flying experience, but no combat experience. It showed and was to have major effects on his handling of the early engagements such as Coomalie (to be fair he learnt quickly). Gibbs was supported by two good quality flight section leaders, of which only one, Flt Lt Bob Foster had actual combat experience.

Its a common fallacy that 1 FW was an experienced elite unit. It came to be, and the wartime hype made it out to be, but the truth, at the start of the campaign was that it was a very green unit with inadequate training and little experience.

 

[Hiromachi]

I have the A. Cooper book, dont have to tell me.
I meant that they were veterans as they had some former records, not necessarily that they were combat experienced. Thus I was referring that some of them could be aware of the changes in operation of the Merlins and higher boosts permitted.

The pilots might have been aware of the boost changes, but that doesn't mean that the Merlin 46s used in Australia had been modified to use the increased boost. The RAAF's Pilot's Notes show +12 lbs boost and papers in the Australian National Archives show that +12 lbs boost was the maximum used (note that the images don't seem to be available for download).

Unless other information can be found, confirming that the RAAF allowed the 1 Wing Spitfire VCs to use +16 lbs, the documents listed are all we have to go on - anything else is speculation.

True, well, it may be simply the case of combat specific, the areas Spitfires would have to fly over were great and higher boosts, while safe for combat usage would reduce the lifetime of engine. And getting new engines to Darwin ...
Still, +12 is not a catastrophe.

 

[parsifal]

Not many had combat experience, and most pilots were barely and inadequately trained. Its possible they had some knowledge as you suggest, but more possible that they did not. 452 for example, after all the manpower changes, when reformed in Australia had just three pilots with any experience, the rest were hot out of the training schools, moreover the leadership of this unit had not seen anything more modern than a Hawker Demon on which to fly.

Australia had no proper fighter wings even as late as 1941. aqll of the fighter units that had been raised had been passed immediately to British or US control, so the experiences of the RAAF with modern fighter controls, tactics, and equipment was extremely limited. All this is in the book.

1 FW was literally the 1st fighter wing to be formed under RAAF control and the lack of experience and even basic knowledge needs to be taken into account in understanding why things happened as they did.

 

[Aozora]

True, well, it may be simply the case of combat specific, the areas Spitfires would have to fly over were great and higher boosts, while safe for combat usage would reduce the lifetime of engine. And getting new engines to Darwin ...
Still, +12 is not a catastrophe.

It's more than likely that because there was no Fw 190 to fight, the RAAF and RAF didn't consider that the Spitfire needed +16 lbs boost. This also, as you say, had the benefit of reducing wear and tear and, incidentally, fuel. Still, +16 lbs boost could have been useful, considering how well the A6M3 performed against the VC.

 

[Barrett]

I'm way late to this thread but just discovered it while reviewing some material from Joe Foss, whom I was fortunate to know well.

In December 42, between tours at Guadalcanal, Joe hooked up with Caldwell's wing near Sydney and of course relished the chance to fly a Spitfire. As well as I recall Joe's descriptions over the years, he said, "I understand that a lot of you guys are aces. Well, congratulations, but what worked against the Germans won't work here. Now maybe you think that if a stiff-necked American can get 23 Jap(anise) in his 8,000-lb airplane, you're gonna clean up in your 6,700-lb airplane. But I'm here to tell you: if you try dogfighting a Zero he'll eat your lunch."

He added, "We have a saying: "If you're alone and you meet a Zero, run like hell because you're outnumbered."

 

[manta22]

I was recently given a soft-cover book "Air War Over Darwin" and I'm not going to keep it. If anyone wants it, let me know.

 

[RCAFson]

Just to show that RAAF Merlin 46 engined Spitfires were using 16lb boost by Sept 1943 because the speeds recorded at SL and 10k ft are only possible with 16lb boost:

To RAAF HQRS

From OHQ RAAF KWAY

6 Sept 1943




Spitfire Aircraft Engineering.


5 Spitfire Mk 5 aircraft given extensive test fights here successively with each of the following types of of air intake assembly and engine cowling. (A) original tropical (B) New Tropical with bypass valves (C) Temperate.

Average max speeds were

1 sea level) A) 312 B) 312) C) 316

2 10000ft) A) 355.5 B) 355.5 C) 360

3 at FTH ) A) 357 B) 358.5 C) 363

Considered that improvements in speed were too small to warrant departure from original type tropicalization hence new scheme will not be applied retrospectively to Mk5 aircraft. Latest tropical intake with bypass valve will be incorporated Mk 8 aircraft.
from Australian Archives:
Title
DTS [Directorate Technical Services] - Spitfire Aircraft - Performance comparison - tropical and non-tropical types
Contents date range
1942 - 1944
Series number
A705

BWOC here's the RAE chart for Spitfire V speed with 16lb boost pencilled in:

http://www.wwiiaircraftperformance.org/Spitfire_V_Level_Speed_RAE.jpg