Alternative RAF, 1936-41?

[xv107]

These are most of the senior RAF officers between 1919 and 1939 - Group commanders, Area Commanders! staff College, Air Council, etc holding rank of Air Cdre or higher on 3 Sept 39

Trenchard: Royal Scots (Infantry)
Jack Salmond: King’s Own Royal Lancaster Rgt (infantry)
Geoff Salmond: Royal Artillery
Ellington: Royal Artillery
Newall: Royal Warwickshire, then 2nd Gurkha Rifles (infantry)
Portal: Royal Engineers

Jack Higgins: (AOC Iraq) - R Artillery
John Steel: (ADGB and first AOC Bomber Command) - Royal Navy
Brooke-Popham - Oxfordshire Light Infantry
Ludlow-Hewitt: Royal Irish (infantry)
Tedder: Dorsetshire Regiment (infantry)
Boyd: 5th Indian Cavalry
Gossage : Royal Field Artillery
Mitchell: Dorsetshire Regiment (infantry)
Courtney: RN
MacLean: Royal Fusiliers (infantry)
Dowding: Royal Garrison Artillery
Leigh Mallory: Lancashire Fusiliers (infantry)
Douglas: Royal Field Artillery
Longmore: RN
Cave-Browne-Cave: RN
Burnett: Highland Light Infantry (but previous service with Imperial Yeomanry as Pte in Boer War saw attached service to them from HLI, and then with West African Frontier Force, so some mounted infantry experience; left Army pre-1914; rejoined, straight to RFC
Bowhill: RN
Nicholl: London Scottish Volunteers (infantry); S Rhodesian Volunteers (infantry)
Swann: RN
Game: Royal Artillery
Webb-Bowen: Bedfordshire Regiment (infantry)
Becke: Sherwood Foresters (infantry; retired 1920
Pitcher: 24th Rgt of Foot, but transferred to Indian Cavalry (retired 1929 after 2 x Group commands)
Masterman: RN
MacEwen: Argyll & Sutherland Highlanders
Scarlett: RN
Tyssen: Somerset Light Infantry
Saul: Royal Army Service Corps
Andrews: Royal Scots (sneaks into list by 2 days)
Hill: Northumberland Fusiliers (infantry)
Vyvyan: RN
Babington: Royal Hampshire Regiment
Sutton: Westmoreland & Cumberland Yeomanry (mounted regiment, but he joined October 14 and was RFC by autumn 1915)
Blount: Queen’s (Royal West Surrey) Regiment (infantry. Great-Great Uncle of James Blunt, by the by)
Harris: Rhodesia Regiment
Coningham: Canterbury Mounted Regiment. Invalided out after 18 months, joined RFC
Pierse: RN
Freeman: Manchester Regiment (infantry), but RFC before Aug 1914
D’Albiac: Royal Marines
Joubert: Royal Field Artillery
Barratt: Royal Field Artillery
Playfair: Royal Field Artillery
Gerrard: Royal Marines
Gordon: Royal Marines
Foster: Royal West Kent (infantry)
Baldwin: R Irish Hussars (cavalry)
Quinnell: Royal Artillery
Herbert: R Warwickshire Rgt (infantry; strictly speaking, shouldn’t be on list as retired as an Hon Air Cdre, but held important training role in mid-20s)
SW Smith: Royal Field Artillery

There are some others, but - could you tell me where this notion that the inter-war RAF was dominated by cavalry officers comes from, please? There were more Royal Marines (via the RNAS, of course) than donkey wallopers…

The issue, in part, is that the RAF had nowhere near the social cachet of the cavalry regiments, and many officers with a pre-war cavalry background ((who’d joined the RFC on attachment from their regiments, which - like the RFC- specialised in recce as it sounded interesting), had no intention of leaving the Army.

 

[xv107]

HH #20 recommended J James, The Paladins. Well, he was right and many thanks. In essence: Expansion Plan A was all there ever was. Others were fiction, sources of money but not...men, airfields, aircraft. The fighter or bomber argument behind some of the Plans is not discussed at all: author has Staffs unwavering from establishing the Force we actually had by mid-'39, bar only to add the Expeditionary Force...on Battle/Blenheim. He bases his thesis on dissecting Officer postings in the RAF Lists, 1933-39. Before "compulsion", 4/38, shutting down much civil work, such as auto, to transfer resources into Aero, and before conscription, 26/4/39, strength was only in number plates.

James gets quite a bit wrong. Air Cdre Fin Monahan wrote his PhD on RAF culture and firmly disagrees with a fair amount of James’s work as a result of his drawing on archival material James either couldn’t access or didn’t look at. The thesis should be downloadable from the University of Birmingham library (I’ll put a link up when on a device which behaves itself when cutting and pasting links, which this one doesn’t)

 

[HoHun]

Hi,

James gets quite a bit wrong. Air Cdre Fin Monahan wrote his PhD on RAF culture and firmly disagrees with a fair amount of James’s work as a result of his drawing on archival material James either couldn’t access or didn’t look at. The thesis should be downloadable from the University of Birmingham library (I’ll put a link up when on a device which behaves itself when cutting and pasting links, which this one doesn’t)

Thanks for the reference!

I believe I found the link already:

http://etheses.bham.ac.uk/8306/1/Monahan18PhD.pdf

Looking forward to learning more about this!

Regards,

Henning (HoHun)

 

[xv107]

Hi,

James gets quite a bit wrong. Air Cdre Fin Monahan wrote his PhD on RAF culture and firmly disagrees with a fair amount of James’s work as a result of his drawing on archival material James either couldn’t access or didn’t look at. The thesis should be downloadable from the University of Birmingham library (I’ll put a link up when on a device which behaves itself when cutting and pasting links, which this one doesn’t)

Thanks for the reference!

I believe I found the link already:

http://etheses.bham.ac.uk/8306/1/Monahan18PhD.pdf

Looking forward to learning more about this!

Regards,

Henning (HoHun)

That’s the badger. Cheers.

 

[Hood]

These are most of the senior RAF officers between 1919 and 1939 - Group commanders, Area Commanders! staff College, Air Council, etc holding rank of Air Cdre or higher on 3 Sept 39

That is a very interesting listing.
Certainly Army heavy, not many former RNAS officers remained it seems at the upper echelons.

That might not be too surprising perhaps. The early RNAS personnel were often keen aviators, but I don't think the RNAS was necessarily well regarded within the RN in terms of career hierarchies and promotions. It would be interesting to speculate about how many RNAS officers would have transferred back out into other branches of the Navy had an independent RNAS existed post-1918.

I'd be wary of drawing too much inference on officers' abilities by their regiment when joining the Army. All of these had 20 years to get inculcated into air doctrine by 1939. Certainly given how low they had Army cooperation on the agenda they had cleaned the mud off their boots long ago.

 

[xv107]

The RN was not at all keen on aviators, thinking them very odd sorts indeed. Admiral Phillips is recorded as having told one of his colleagues not to go into aviation as it'd ruin his career. The RNAS expanded dramatically - as you'd expect - in the war, but at the end of it all, despite wanting to have its own air arm, the RN made little accommodation to expand the number of aviators in its ranks. The end result was that most of those wishing to have a career involving aviation stayed with the RAF if the offer to do so was there.

I agree that the background of officers is not as important as suggested, and am challenging the assumption that they were mainly 'cavalry officers'. It's a long-standing stereotype almost as prevalent as the notion that The Few were all jolly posh chaps from public schools (with commissions) who came up with public-school phrases like 'wizard prang', etc. As people on this site know, that's not exactly what the reality was in 1940...


I'd contend (and have elsewhere) that the position re: Army Cooperation is a bit more complex than much of the history allows for. The RAF did a lot of that work in the colonies and mandated territories and did it pretty well (see Rick Newton's recent work as a contrast to Satia and Omissi, for example), but couldn't see how such activity would play into a major war against a European power. From 1919-1933, the only prospective enemy in Europe was France - and nobody really believe this to be credible, even if the press 'scare' contributed to the Salisbury Committee and the slow creation of the air defence system (see Brett Holman on this, for instance). When Germany came along, there was no sense that the UK would send forces to the continent - the 'Continental Commitment' only hove into view in 1938. This required a rapid shift in thinking - and a shift in kit which is a major part of this thread. Was the problem the lack of political/strategic clarity on the need to send an expeditionary force with all that entailed? And when the lightbulb did flicker on, it was too late...

While the RAF's leadership is far from blameless, too many historians, IMO, have seen the RAF as being blindly set on bombing and ignoring army co-operation. I'd contend (and I don't think I'd be alone) that the issue wasn't one of abandoning army cooperation, but thinking about it in blinkered terms of 'Col-Pol' and - as the (not-so-) splendidly politically incorrect phrasing of doctrine had it - 'semi-civilised' opponents rather than Germans with a doctrine for mobile warfare and a clear understanding of the importance of control of the air.

I'd suggest that the picture is more nuanced and that a failure of vision in terms of what a European war would look like - partly driven by the desire to avoid a repetition of the First World War (a desire which probably led to the conceptual equivalent of shoving fingers in the ears and going 'nah, nah, can't hear you!' when it came to thinking about a land war and the air requirements thereof).

That, in turn, drives some of the procurement decisions we're attempting to retrospectively sort out as an interesting thought exercise here.

 

[EwenS]

Another factor to bear in mind is that although the RNAS and RFC were of roughly comparable size on 1 April 1918 on formation of the RAF, when it came to the post WW1 cutbacks the axe fell to a much greater extent on the ex-RNAS element.

In Dec 1918 Coastal Area/10 Group RAF (I’m not clear about its exact designation then) had about 700 aircraft plus airships across more than 70 bases. It was, AIUI, reduced to a single shore based flying boat squadron by 1923.

Where did all those officers go? The RAF didn’t want then. The RN didn’t want them. (Or at least most of them). So it must have been back to civilian life for the vast majority.

So very few ex-RNAS left to rise up through the RAF ranks inter-war.

 

[alertken]

My engine fetish is because the purpose of the platform is to lift it. No aircraft is under-powered, they are over-weight.

“Peregrine, Vulture, Sabre, Hercules VI, Centaurus, Griffon are outstanding examples of (hopes) disappointed or deferred” Prof M.M.Postan, Official History, War Production, HMSO,P167. For this thread staring 1936, add Exe (1,200hp, run 9/36, abandoned 8/40), Vulture (8/39:1,800hp; Mk.V, 3/41: 2,010hp, abandoned 4/42).

You will find assertions that all RR's were voluntarily stopped by Hives to prioritise various Merlins. No. They were stopped by the people paying for them, when they realised RR was over-stretched. If:

Peregrine had worked...Whirlwind was to have gone into Nuffield's Castle Bromwich Agency Factory, so fewer Spitfires, even none after BoB.

if: Vulture had worked, HAL Tornado would have matched FW190 from its arrival, and...no Lancaster.

 

[tomo pauk]

My engine fetish is because the purpose of the platform is to lift it. No aircraft is under-powered, they are over-weight.

What power levels might be expected from R-1830 in years of interest, in order to fit the RAF needs better and cheaper than engine in production in the UK?

“Peregrine, Vulture, Sabre, Hercules VI, Centaurus, Griffon are outstanding examples of (hopes) disappointed or deferred” Prof M.M.Postan, Official History, War Production, HMSO,P167. For this thread staring 1936, add Exe (1,200hp, run 9/36, abandoned 8/40), Vulture (8/39:1,800hp; Mk.V, 3/41: 2,010hp, abandoned 4/42).

R-1830 is no replacement for these engines, bar for Peregrine.
Granted, UK (RAF, FAA, Army) don't need the Peregrine or Exe in any alternative history scenario worth reading.

If:

Peregrine had worked...Whirlwind was to have gone into Nuffield's Castle Bromwich Agency Factory, so fewer Spitfires, even none after BoB.

Peregrine worked.
Problem with it is that for each Peregrine produced, there is one less Merlin produced - a bad math for the RAF, and it was good to cancel it.

 

[pathology_doc]

if: Vulture had worked, HAL Tornado would have matched FW190 from its arrival, and...no Lancaster.

It would be interesting to wonder what happens in a world where the Manchester works, but someone has the bright idea to go ahead with a four-Merlin version anyway.

The other thing you have to consider not happening in a universe where the Vulture is as smooth to develop as the Merlin is the Griffon engine. With a functioning, reliable Vulture in quantity production and development, what role (if any) does the Griffon have?

 

[Apophenia]

if: Vulture had worked, HAL Tornado would have matched FW190 from its arrival, and...no Lancaster.

It would be interesting to wonder what happens in a world where the Manchester works, but someone has the bright idea to go ahead with a four-Merlin version anyway.

The other thing you have to consider not happening in a universe where the Vulture is as smooth to develop as the Merlin is the Griffon engine. With a functioning, reliable Vulture in quantity production and development, what role (if any) does the Griffon have?

Griffon priority would have gone to the FAA for the Firefly.

 

[ngatimozart]

Spitfire's production can be increased by having Westland to get in that bandwagon ASAP. This means either no Lysander or no Whirlwind, or both (yes, Lysander - for better or worse - was made for Army needs, while Whirlwind is sexy). And/or, have Blackburn making Spitfire since we have axed the Botha there. British government can perhaps loan the tooling that was being bought for Castle Bromwich factory to both Blackburn and Westland, so they can make a good number of those in 1939-40 and on. Add some production dispersal as it was the case historically and we can have a lot of extra Spitfires.
Introducing Gloster early into Hurricane business + no Defiant = B-P can also make Spitfires.
I'd also have Saro making Supermarine's flying boats (Saro Lerwick is no more) so they can concentrate on making Spitfires.

Actually I would've kept the Whirlwind, swapping the RR Peregrines for the RR Merlin engines. It was a good ground attack aircraft and fighter with four 20mm cannon that suffered from a dud engine.

Guns - the .303 Brownings were excellent, then next step favored were the 20mm cannons. Shop at Oerlikon since the Hispano 404 is too late? Tony Williams favors/favored the FFL type, even the early Hurricanes and Spitfires will be able to lug two of them per A/C without much of performance lost.

I believe that the only reason that .303 was chosen was because of the extensive supply of .303 ammo left over from WW1. IMHO the ,303 round was inadequate. In actual fact .50 calibre would have been far better and so it was proven later in the war. Six .50 cal guns would've been more than adequate.

Fighter Command had the right aircraft in the Hurricane and Spitfire. Getting rid of the pointless Defiant gives you more of them. Trainers could have been built in greater numbers.
But the real chalkenge is to replace the Battles and Blenheim's of the RAF units sent to France in 1939.

In the real world, the UK didn't get serious about rearming until 1937 / 38, which by then was a tad late. However this isn't the real world and we can be somewhat economical with the history. If the UK started rearming in say 1935 it would have four years before the balloon rose. In that time it could have rationalised the aviation industry somewhat so that instead of a plethora of small companies struggling, there could be say no more than five or six companies with strong design teams.

Secondly, the Air Ministry strengthens its acquisition structures and is more specific in its requirement standards. So it tells the manufactures what it wants, what it expects in return and if the product isn't up to the required standard the company doesn't get paid, and it mightn't get any future work. This means that the RAF and Air Ministry have to be up with the play about what is happening in the aviation world everywhere, and not sitting upon their laurels under the misconception that British aviation technology was the most advanced - it wasn't.

In the real world Fighter Command as short of Hurricanes and Spitfires and it got to the point where AM Dowdling had to request that the PM stop promising the French more RAF fighters. However the biggest problem during the BoB was trained pilots and that could be mitigated by increasing the size of the University Sqns, RAFR and RAFVR from 1935. Also the Empire Air Training Scheme could've been established say in 1936 / 37 with it easily ramped up a lot quicker when war broke out in 1939. This would've have begun the RAF an ample supply of trained aircrew by the time the BoB started.

For the RAAF, RCAF, RNZAF and SAAF, I would be strongly suggesting that UK govt strongly suggest to the four Dominion governments that they acquire Curtiss P-40 Warhawks, Douglas A-20 Havocs, North American B-25 Mitchells, and Consolidated PBY-5 Catalinas from the US in the short - medium term to build up their air forces. They could later acquire the North American P-51 Mustang and Consolidated B-24 Liberator when they becomes available. Later the Canadians and Australians could and would licence build British aircraft. This keeps all UK production for the RAF without having to worry about Dominion requirements. Also RAF requirements have to take priority over any thoughts of exports.

IMHO with the benefit 20/20 hindsight this would be my suggested way for rebuilding the RAF fighter force in both quality and quantity in a four year period.

 

[tomo pauk]

Actually I would've kept the Whirlwind, swapping the RR Peregrines for the RR Merlin engines. It was a good ground attack aircraft and fighter with four 20mm cannon that suffered from a dud engine.

What kind of numbers we're talking for the Merlin Whirly? 200, 500, 1000, more?

I believe that the only reason that .303 was chosen was because of the extensive supply of .303 ammo left over from WW1. IMHO the ,303 round was inadequate. In actual fact .50 calibre would have been far better and so it was proven later in the war. Six .50 cal guns would've been more than adequate.

British will probaby want to have the LMG of any type in their caliber?
I'm not against the .50, just that a good 20mm is better. The .50s of 1936 were not as good as the ones from 1942/43/44.

Secondly, the Air Ministry strengthens its acquisition structures and is more specific in its requirement standards. So it tells the manufactures what it wants, what it expects in return and if the product isn't up to the required standard the company doesn't get paid, and it mightn't get any future work. This means that the RAF and Air Ministry have to be up with the play about what is happening in the aviation world everywhere, and not sitting upon their laurels under the misconception that British aviation technology was the most advanced - it wasn't.

That was the case historically - in the wast % of cases the companies delivered exactly what was asked from. It was Air Ministry's good decision to go with Hurricane, Spitfire or Wellington, as much as it was AM's fault to specify and buy Gladiator and Defiant (thus also dooming the Roc), or to buy so many Battles, or to specify both Botha (that was indeed botched by Blackburn) and Beaufort.

In the real world Fighter Command as short of Hurricanes and Spitfires and it got to the point where AM Dowdling had to request that the PM stop promising the French more RAF fighters. However the biggest problem during the BoB was trained pilots and that could be mitigated by increasing the size of the University Sqns, RAFR and RAFVR from 1935. Also the Empire Air Training Scheme could've been established say in 1936 / 37 with it easily ramped up a lot quicker when war broke out in 1939. This would've have begun the RAF an ample supply of trained aircrew by the time the BoB started.

Yes, having more trained pilots is a boon.
Having Air Ministry ordering more Hurricanes instead of Gladiator, no Defiants (for more Spitfires), 500-700 Battles instead of 2100 = thousands more of useful fighters.

For the RAAF, RCAF, RNZAF and SAAF, I would be strongly suggesting that UK govt strongly suggest to the four Dominion governments that they acquire Curtiss P-40 Warhawks, Douglas A-20 Havocs, North American B-25 Mitchells, and Consolidated PBY-5 Catalinas from the US in the short - medium term to build up their air forces. They could later acquire the North American P-51 Mustang and Consolidated B-24 Liberator when they becomes available. Later the Canadians and Australians could and would licence build British aircraft. This keeps all UK production for the RAF without having to worry about Dominion requirements. Also RAF requirements have to take priority over any thoughts of exports.

Dominons were already focusing on US-made aircraft, despite the London 1st objecting that while promissing a lot, and later barely offering help to kick-start the domestic aero industry. RAF's job was not taking care of dominion's aircraft anyway.

 

[ngatimozart]

Actually I would've kept the Whirlwind, swapping the RR Peregrines for the RR Merlin engines. It was a good ground attack aircraft and fighter with four 20mm cannon that suffered from a dud engine.

What kind of numbers we're talking for the Merlin Whirly? 200, 500, 1000, more?

Probably 500 to start with.

I believe that the only reason that .303 was chosen was because of the extensive supply of .303 ammo left over from WW1. IMHO the ,303 round was inadequate. In actual fact .50 calibre would have been far better and so it was proven later in the war. Six .50 cal guns would've been more than adequate.

British will probaby want to have the LMG of any type in their caliber?
I'm not against the .50, just that a good 20mm is better. The .50s of 1936 were not as good as the ones from 1942/43/44.

John Brownings 50 cal was available from FN in Belgium and could've been licence built in the UK. I too like the 20mm but you are limited with the number of rounds per gun and a combination of the 50 cal and 20mm is better.

Secondly, the Air Ministry strengthens its acquisition structures and is more specific in its requirement standards. So it tells the manufactures what it wants, what it expects in return and if the product isn't up to the required standard the company doesn't get paid, and it mightn't get any future work. This means that the RAF and Air Ministry have to be up with the play about what is happening in the aviation world everywhere, and not sitting upon their laurels under the misconception that British aviation technology was the most advanced - it wasn't.

That was the case historically - in the wast % of cases the companies delivered exactly what was asked from. It was Air Ministry's good decision to go with Hurricane, Spitfire or Wellington, as much as it was AM's fault to specify and buy Gladiator and Defiant (thus also dooming the Roc), or to buy so many Battles, or to specify both Botha (that was indeed botched by Blackburn) and Beaufort.

Definitely. However the RAAF had good success with the Beaufort in the Pacific.

WRT the Wellington, I wonder what a larger four engined variant would have been like? Barnes Wallis's design was excellent resulting in the aircraft being able to sustain a fair amount of combat damage.

In the real world Fighter Command as short of Hurricanes and Spitfires and it got to the point where AM Dowdling had to request that the PM stop promising the French more RAF fighters. However the biggest problem during the BoB was trained pilots and that could be mitigated by increasing the size of the University Sqns, RAFR and RAFVR from 1935. Also the Empire Air Training Scheme could've been established say in 1936 / 37 with it easily ramped up a lot quicker when war broke out in 1939. This would've have begun the RAF an ample supply of trained aircrew by the time the BoB started.

Yes, having more trained pilots is a boon.
Having Air Ministry ordering more Hurricanes instead of Gladiator, no Defiants (for more Spitfires), 500-700 Battles instead of 2100 = thousands more of useful fighters.

TBH I would've strangled the Defiant and Battle at birth.

For the RAAF, RCAF, RNZAF and SAAF, I would be strongly suggesting that UK govt strongly suggest to the four Dominion governments that they acquire Curtiss P-40 Warhawks, Douglas A-20 Havocs, North American B-25 Mitchells, and Consolidated PBY-5 Catalinas from the US in the short - medium term to build up their air forces. They could later acquire the North American P-51 Mustang and Consolidated B-24 Liberator when they becomes available. Later the Canadians and Australians could and would licence build British aircraft. This keeps all UK production for the RAF without having to worry about Dominion requirements. Also RAF requirements have to take priority over any thoughts of exports.

Dominons were already focusing on US-made aircraft, despite the London 1st objecting that while promissing a lot, and later barely offering help to kick-start the domestic aero industry. RAF's job was not taking care of dominion's aircraft anyway.

Yes London promised a lot and delivered sweet stuff all. In mid 1941 the NZ Govt requested to purchase 48 Beaufighters but London said a flat no. The thing was the Beaufighters would have been an excellent capability for the RNZAF in the South West Pacific. The RAAF Beaufighters absolutely annihilated the Japanese.

 

[tomo pauk]

Probably 500 [of Merlin Whirlys] to start with.

Westland can make 1000 Spitfires, each with 2 cannons, for the same investment of 1000 Merlins and 2000 cannons.

Definitely. However the RAAF had good success with the Beaufort in the Pacific.

WRT the Wellington, I wonder what a larger four engined variant would have been like? Barnes Wallis's design was excellent resulting in the aircraft being able to sustain a fair amount of combat damage.

RAAF would've probably do even better with Mosquitoes or Beaufighters?
A 4-engined Wellington would've looked a lot like the Vickers Warwick with the wing from the Fw 200?

 

[Hood]

Having recently been reminded the Boulton Paul P.92 was to have a 20mm cannon firing through the propellers of its Napier Sabres (in-between the crankshafts and through the centre of the blower), I wonder whether this might have been worth applying to single-engined Sabre fighters?

The RAF discounted the 0.50in calibre in 1928, maybe then it was right to do so. Certainly by 1935 it was thinking of 20mm as the future and you can't deny that was a good move.

Given in the late 1930s the Royal Armoured Corps with its separate supply chain was given permission to adopt 7.92 x 57 rather than go to the expense and effort to alter the BESA, it seems odd the RAF had not used the same argument before? I suppose two factors against this are; a) cost at a time of stingy RAF budgets during the 1920s and b) the colonial policing role where operating up country it was probably handy to be able to pick up ammo from the Army and made stockpiling ammo easier.
By 1935 as I say, the 20mm looked like the gun of the future and probably made no sense to then ask for a new rimless bullet and have to change all the guns then in use.

The only other late 30s (perhaps more realistically early-40s) choice would be the 15mm BESA based on the ZB60, a hard hitting round but with a slow rate-of-fire to improve accuracy (15 x 104mm cartridge, 75 grams bullet, 818.3 m/s (2,685 ft/s) muzzle velocity and 450 rpm rate of fire).

 

[tomo pauk]

Having recently been reminded the Boulton Paul P.92 was to have a 20mm cannon firing through the propellers of its Napier Sabres (in-between the crankshafts and through the centre of the blower), I wonder whether this might have been worth applying to single-engined Sabre fighters?

The RAF discounted the 0.50in calibre in 1928, maybe then it was right to do so. Certainly by 1935 it was thinking of 20mm as the future and you can't deny that was a good move.

Someone will 1st have to redesign the Sabre so it can have the abiity of cannon firing thought the prop hub. Perhaps the design talent is better used so the Sabre is a reliable engine already by 1942?
Having a cannon firing through the prop hub allows for good/great firepower when engines are 800-1000 HP types, while not experiencing a decrease in performance vs. having two cannons in the wings set-up. With 2000 HP engines, we'd probably want a lot more firepower than what a single cannon provides. Talk 4 cannons? Might as well go to the wings.

The .50 would've make a lot of sense as a defensive/turret gun.

Given in the late 1930s the Royal Armoured Corps with its separate supply chain was given permission to adopt 7.92 x 57 rather than go to the expense and effort to alter the BESA, it seems odd the RAF had not used the same argument before? I suppose two factors against this are; a) cost at a time of stingy RAF budgets during the 1920s and b) the colonial policing role where operating up country it was probably handy to be able to pick up ammo from the Army and made stockpiling ammo easier.
By 1935 as I say, the 20mm looked like the gun of the future and probably made no sense to then ask for a new rimless bullet and have to change all the guns then in use.

The only other late 30s (perhaps more realistically early-40s) choice would be the 15mm BESA based on the ZB60, a hard hitting round but with a slow rate-of-fire to improve accuracy (15 x 104mm cartridge, 75 grams bullet, 818.3 m/s (2,685 ft/s) muzzle velocity and 450 rpm rate of fire).

The RAC might've as well jumped on the .303 Browning, but with the heavier barrel (airflow is not great in the tanks/AFVs).
Rimmed rounds work great even in 21st century in machine guns, semi-automatics and hand-operated bolt rifles.

Italian 12.7mm was in use by the time of Spanish civil war, so that's another option. Better RoF than the .50 BMG before 1940, 750 rd/min vs. 600-650. About the BESA 15mm - a good candidate to modify it to 20mm, in the vein of how MG 151/15 morphed in the MG 151/20?

 

[Hood]

Someone will 1st have to redesign the Sabre so it can have the abiity of cannon firing thought the prop hub. Perhaps the design talent is better used so the Sabre is a reliable engine already by 1942?

Well we're talking early Sabre here, the idea was raised in 1938 when it was still very much a Halton brainchild.
The idea was the blast tube would pass concentrically through the compressor impeller, between the crankshafts and and through the propeller hub/spinner and would take either a 20mm cannon or a .303in machine-gun.
But it seems clear it would be a separate development. I don't think work went very far on this.

Talk 4 cannons? Might as well go to the wings.

Agreed, much better all round. My thought was whether the motor cannon might have encouraged designers to look at lighter fighters or perhaps as a method of trying to obtain better laminar flow on outer wings but not having cannon ports on the wings.

 

[robunos]

The only other late 30s (perhaps more realistically early-40s) choice would be the 15mm BESA based on the ZB60, a hard hitting round but with a slow rate-of-fire to improve accuracy (15 x 104mm cartridge, 75 grams bullet, 818.3 m/s (2,685 ft/s) muzzle velocity and 450 rpm rate of fire).

The 15mm Besa was not a good gun; see :-

Besa machine gun - Wikipedia

en.wikipedia.org

'. . . the weapon was usually used for single shots as it was difficult to fire accurately in automatic.'

British Military Small Arms Ammo - 15mm BESA

In the period immediately before WW2 a number of Czechoslovak designed weapons were adopted by Britain, either in redesigned form like the Bren gun or in their original form like the 7.92mm ZB53 and ZB60 (BESA). The 15mm ZB60 was essentially an enlarged version of the ZB53, scaled up to use the

sites.google.com

'In January 1941 consideration was given to using the 15mm BESA (and the 7.92mm version) to augment aircraft armament in the event that enemy bombing action disrupted supply of the 20mm Hispano and .303 inch Browning guns. Some trials were carried out using weapons with the barrel shortened by 12 inches but by March 1941 the Ordnance Board stated that no further action was required regarding using the 15mm BESA for Air Service.'

cheers,
Robin.

 

[robunos]

Someone will 1st have to redesign the Sabre so it can have the abiity of cannon firing thought the prop hub. Perhaps the design talent is better used so the Sabre is a reliable engine already by 1942?

Time to jump on my favourite hobby horse . . . in my opinion, it would have been better to cancel the Sabre, and re-deploy the resources and manpower to Centaurus development and production. Interestingly, I came across this link on the 'Beyond the Sprues' forum :-

Tempest II Tactical Trials

A comparison between the Sabre engined Tempest V, and Centaurus engined Tempest II. With the exception of turn rate, the latter was judged superior . . .

cheers,
Robin.

 

[tomo pauk]

Someone will 1st have to redesign the Sabre so it can have the abiity of cannon firing thought the prop hub. Perhaps the design talent is better used so the Sabre is a reliable engine already by 1942?

Time to jump on my favourite hobby horse . . . in my opinion, it would have been better to cancel the Sabre, and re-deploy the resources and manpower to Centaurus development and production. Interestingly, I came across this link on the 'Beyond the Sprues' forum :-

Tempest II Tactical Trials

A comparison between the Sabre engined Tempest V, and Centaurus engined Tempest II. With the exception of turn rate, the latter was judged superior . . .

cheers,
Robin.

What to do with Napier anyway, for 1936-41? Dagger was barely used in the ww2, the Sabre is too late for the time period of this thread. Have them make Bristol or RR engines?

 

[Apophenia]

... Italian 12.7mm was in use by the time of Spanish civil war, so that's another option. Better RoF than the .50 BMG before 1940, 750 rd/min vs. 600-650...

The Breda-SAFAT gun used short-recoil and was as heavy as the big Browning. Its 12.7 x 81 round was based on Vickers' .5"V/565 - a semi-rimmed version of their 0.5-inch round (the .5V/580). One difference was the Italians developing explosive shells (technically illegal in 12.7). The explosive charge was very small but the Regia Aeronautica still put great stock in these rounds.

As Hood said, the RAF had discounted 0.5-inch calibre in 1928 - mainly because .303 was then seen as sufficient. But, according to Tony Williams, the Vickers 0.5-inch was a good performer after some bugs were worked out. If you want a 0.5-inch gun, I would say that the Vickers gun - especially firing the unrimmed .5V/580 - would be a superior candidate compared with the Breda-SAFAT.

If greater hitting power was desired, the .5V/565 was scaled up as the V/690 for the Vickers Class D gun. That naval gun (and its 45 inch barrel) weighed over 100 lbs. But, perhaps the Vickers 0.5-inch aircraft gun could also be scaled up to fire the same semi-rimmed 12.7 x 120 mm V/690 round?

 

[tomo pauk]

The Breda-SAFAT gun used short-recoil and was as heavy as the big Browning. Its 12.7 x 81 round was based on Vickers' .5"V/565 - a semi-rimmed version of their 0.5-inch round (the .5V/580). One difference was the Italians developing explosive shells (technically illegal in 12.7). The explosive charge was very small but the Regia Aeronautica still put great stock in these rounds.

IIRC any explosive projectile lighter than 400g was illegal? Thus the plethora of 'weak' 37mm fast-firing cannons at the turn of the century.
Italian gun was firing at 700 rd/min, the big airborne Browning was at 600 rd/min before 1941? We also have the Belgian (FN) developments of the BMG that did above 1000 m/s by 1940, however that is a bit too late for the RAF? (paging @Tony Williams )

As Hood said, the RAF had discounted 0.5-inch calibre in 1928 - mainly because .303 was then seen as sufficient. But, according to Tony Williams, the Vickers 0.5-inch was a good performer after some bugs were worked out. If you want a 0.5-inch gun, I would say that the Vickers gun - especially firing the unrimmed .5V/580 - would be a superior candidate compared with the Breda-SAFAT.

Works for me.

If greater hitting power was desired, the .5V/565 was scaled up as the V/690 for the Vickers Class D gun. That naval gun (and its 45 inch barrel) weighed over 100 lbs. But, perhaps the Vickers 0.5-inch aircraft gun could also be scaled up to fire the same semi-rimmed 12.7 x 120 mm V/690 round?

Hmm, how about necking out either of those as much as possible? Talk 15-17-18 mm depending on what can be done, so it can fire a worthwhile HE ammo. Especially the V/690 looks promising, being so big for a 0.50.
At any rate, not waiting for the Hispano to materialize is IMO the 1st priority, so the workable heavy wepons can be installed in the fighters by 1939 in good numbers.

 

[ngatimozart]

Probably 500 [of Merlin Whirlys] to start with.

Westland can make 1000 Spitfires, each with 2 cannons, for the same investment of 1000 Merlins and 2000 cannons.

They could but the spits had neither the range or the ground attack capabilities at the time.

Definitely. However the RAAF had good success with the Beaufort in the Pacific.

WRT the Wellington, I wonder what a larger four engined variant would have been like? Barnes Wallis's design was excellent resulting in the aircraft being able to sustain a fair amount of combat damage.

RAAF would've probably do even better with Mosquitoes or Beaufighters?

The RAAF had both with the Beaufighters from 1942. To misquote Cpl Jones, the Japanese didn't like it up 'em. They definitely didn't have a sense of humour about it. IIRC at some stage the Aussies replaced the .303 with .50 cal. The Mosquitos arrived later but they had delamination problems with them so they took quite a while to enter service. The glues didn't like the heat and humidity.

A 4-engined Wellington would've looked a lot like the Vickers Warwick with the wing from the Fw 200?

Yep ugly blighter. Like Basil Fawlty's trouble and strife.

 

[EwenS]

The first RAAF Beaufighters came from British production lines. 218 Mk.Ic, VIc, & X between 1942 and July 1944. The first Australian built Beaufighters didn’t appear until May 1944, following the completion of Beaufort production.

The first Australian built Mosquito was completed in July 1943 and the next in April 1944 such were the problems. And again production had to be augmented by Mk.VI & PR.XVI from the U.K.

As for what a 4 engined Wellington would look like, take a look at the Windsor.

Vickers Windsor - Wikipedia

en.m.wikipedia.org

 

[tomo pauk]

They could but the spits had neither the range or the ground attack capabilities at the time.

Depends what time we talk about. Whirly was barely operative before the BoB ended. Both were short ranged, neither was a ground attacker per se.
In 1941, a Spitfire with drop tank was longer ranged, the Whirly never gotten the drop tank facility (can be done, just it was not done). Ground attack capability depended mostly on the will of the RAF to attach bomb shackles on a fighter.
Yes, 4 cannons will do better than 2.

Having Westland make Spitfires from, say, mid-1939, leaves a lot of Spitfires to have when action starts (mostly early 1940 for the RAF FC). No need to sit the hard-to-come-by pilots in any less performing fighter, bar sometimes the Hurricane. Also opens the doors for the Spitfire III (390+ mph in mid-1940), since there is no dire need to up-engine the Hurricane with Merlin 20.

 

[Siberia]

One suggestion from another site was for Bristol to create their own version of the Pratt & Whitney R-2800 by taking the nine-cylinder Perseus and 'twinning' it to make an eighteen-cylinder engine. Granted they would have to overcome various issues like cooling and vibration but if successful it would be very handy to have – as well as improving the performance of various bombers it would also potentially provide a single, superior, engine for the Fleet Air Arm's aircraft.

For a different take, what about getting in on the LB-30/B-24 as early as possible and purchasing more of them?

Rather than this why not try and fix the Short Stirling? It was the Air Ministry's insistence on a maximum wingspan – a wrongheaded attempt to keep aircraft weights down – which necessitated increasing angle of the wing causing it to fly with a nose-down attitude and the associated performance issues. As the Halifax and Lancaster come into service ideally it would free up the Stirling to be transferred to Coastal Command.

Thread is about the RAF, the FAA might use it's own thread?

Well up until 24 May 1939 the Fleet Air Arm was a part of the RAF.

Trick with Hispano 404 is that it was just being produced in the UK from mid-1940, leaving the BoB dynamic duo without the cannon armament; the cannon itself was unreliable even in 1941.

IIRC wasn't the late entry into service of the Hispano down to an almost epic lack of urgency on the part of the Air Ministry when it came to testing and licensing the weapon?

 

[Tony Williams]

IIRC wasn't the late entry into service of the Hispano down to an almost epic lack of urgency on the part of the Air Ministry when it came to testing and licensing the weapon?

I don't think so - the impression I have is that the RAF was very keen to get it into service as quickly as possible.

The problems associated with the gun were many and various, to do with debugging the design, modifying it to use imperial measurements rather than metric, reaching agreement with Hispano-Suiza for licensed production, and setting up an assembly line.

The biggest delay which I am aware of is that Hispano wanted to make all of the guns themselves, in a new purpose-built factory in the UK, and control all aspects of the design and production. The RAF insisted that they must have the right to place orders with other gun makers and to modify the design if required (which it certainly was). The factory was built, but most of the guns were built elsewhere.

 

[pathology_doc]

increasing angle of the wing causing it to fly with a nose-down attitude

No, that was the Whitley. The Stirling had an unusually high take-off attitude.

 

[tomo pauk]

Rather than this why not try and fix the Short Stirling? It was the Air Ministry's insistence on a maximum wingspan – a wrongheaded attempt to keep aircraft weights down – which necessitated increasing angle of the wing causing it to fly with a nose-down attitude and the associated performance issues. As the Halifax and Lancaster come into service ideally it would free up the Stirling to be transferred to Coastal Command.

Let's point the finger on the Shorts.
They made a too big a bomber, with a big and long fuselage, and a wing that was already of 20% greater area than the B-17/B-24/Halifax/Lancaster. That left it underpowered, that in return meant the bomb load was meh, and performance was bad.
This recent thread might be worth reading: link

IIRC wasn't the late entry into service of the Hispano down to an almost epic lack of urgency on the part of the Air Ministry when it came to testing and licensing the weapon?

Air Ministry saw no urgency on adopting any cannons until into late 1930s, by what time Germany and France already have the Oerlikon-pattern cannons in production and, for the French, in service. Oerlikon cannons were available already in 1920s for anyone willing to buy, Hispano was not, not even for the French that used Oerlikon models on D.510 and MS 406.

One suggestion from another site was for Bristol to create their own version of the Pratt & Whitney R-2800 by taking the nine-cylinder Perseus and 'twinning' it to make an eighteen-cylinder engine. Granted they would have to overcome various issues like cooling and vibration but if successful it would be very handy to have – as well as improving the performance of various bombers it would also potentially provide a single, superior, engine for the Fleet Air Arm's aircraft.

Any 2-row radial had vibration and cooling issues to overcome, some being better and earlier solving them than another types. Unfortunately, Fedden focused on improving the valve gear, instead of improving the superchargers. For piston aero engines, s 2-valve head with excellent superchager > an impeccable valve gear with bad S/C.

 

[NOMISYRRUC]

Thread is about the RAF, the FAA might use it's own thread?

Well up until 24 May 1939 the Fleet Air Arm was a part of the RAF.

For what it's worth, "Fleet Air Arm" was a shortening of "Fleet Air Arm of the Royal Air Force".

Quote from Page 7 of Fleet Air Arm Aircraft, Units and Ships 1920-1939 by Ray Sturtivant

On 1st April 1924, exactly a year after these new carrier-borne flights had begun to form, they were given the collective title Fleet Air Arm of the Royal Air Force, soon shortened in practice to the now familiar "Fleet Air Arm".

However, it was known as the "Air Branch" for its first 14 years as part of the Royal Navy.

Quote from Page 13 of Fleet Air Arm Aircraft, Units and Ships 1920-1939 by Ray Sturtivant

A much more fundamental change was in the offing, however. Ever since the Royal Naval Air Service had been amalgamated into the RAF on 1st April 1918, the Royal Navy had made repeated efforts to win back its air arm. Success finally came after the question had been referred to arbitration, and on 21st July 1937 Sir Thomas Inskip, in what later came to be known as the "Inskip Award," recommended to the Cabinet that the Navy have full control of its aircraft, training and organisation. It was to be nearly 2 years, however, before this could be properly implemented, and even longer before the last RAF ground crew ceased to be required, some serving in carriers at the end of the Second World War. The title Fleet Air Arm of the Royal Air Force was to be dropped, and the service would become officially the "Air Branch," but in practice the term "Fleet Air Arm" never went out of use, and in fact was officially readopted in 1953.

 

[NOMISYRRUC]

...... and the Botha was too lethal to its own crew to even use as a trainer due to poor stability and control - my grandfather turned down a chance to fly in one for that reason. .....

Except the Botha was used as a trainer. No 10 (Observers) Advanced Flying Unit was formed as late as May 1942 with 44 Bothas and 21 Battles in its fleet of some 120 aircraft based at Dumfries and Annan in South West Scotland. The Battles were replaced first, by the end of the year, with withdrawal of the Bothas started but not completed until Aug 1943. The replacement for both types was the Anson. The last of the Bothas weren't withdrawn from second line duties until Sept 1944.

Which is ironic because the Anson was one of the aircraft that the Botha was to have replaced.

 

[NOMISYRRUC]

These are most of the senior RAF officers between 1919 and 1939 - Group commanders, Area Commanders! staff College, Air Council, etc holding rank of Air Cdre or higher on 3 Sept 39

Trenchard: Royal Scots (Infantry)
Jack Salmond: King’s Own Royal Lancaster Rgt (infantry)
Geoff Salmond: Royal Artillery
Ellington: Royal Artillery
Newall: Royal Warwickshire, then 2nd Gurkha Rifles (infantry)
Portal: Royal Engineers

Jack Higgins: (AOC Iraq) - R Artillery
John Steel: (ADGB and first AOC Bomber Command) - Royal Navy
Brooke-Popham - Oxfordshire Light Infantry
Ludlow-Hewitt: Royal Irish (infantry)
Tedder: Dorsetshire Regiment (infantry)
Boyd: 5th Indian Cavalry
Gossage : Royal Field Artillery
Mitchell: Dorsetshire Regiment (infantry)
Courtney: RN
MacLean: Royal Fusiliers (infantry)
Dowding: Royal Garrison Artillery
Leigh Mallory: Lancashire Fusiliers (infantry)
Douglas: Royal Field Artillery
Longmore: RN
Cave-Browne-Cave: RN
Burnett: Highland Light Infantry (but previous service with Imperial Yeomanry as Pte in Boer War saw attached service to them from HLI, and then with West African Frontier Force, so some mounted infantry experience; left Army pre-1914; rejoined, straight to RFC
Bowhill: RN
Nicholl: London Scottish Volunteers (infantry); S Rhodesian Volunteers (infantry)
Swann: RN
Game: Royal Artillery
Webb-Bowen: Bedfordshire Regiment (infantry)
Becke: Sherwood Foresters (infantry; retired 1920
Pitcher: 24th Rgt of Foot, but transferred to Indian Cavalry (retired 1929 after 2 x Group commands)
Masterman: RN
MacEwen: Argyll & Sutherland Highlanders
Scarlett: RN
Tyssen: Somerset Light Infantry
Saul: Royal Army Service Corps
Andrews: Royal Scots (sneaks into list by 2 days)
Hill: Northumberland Fusiliers (infantry)
Vyvyan: RN
Babington: Royal Hampshire Regiment
Sutton: Westmoreland & Cumberland Yeomanry (mounted regiment, but he joined October 14 and was RFC by autumn 1915)
Blount: Queen’s (Royal West Surrey) Regiment (infantry. Great-Great Uncle of James Blunt, by the by)
Harris: Rhodesia Regiment
Coningham: Canterbury Mounted Regiment. Invalided out after 18 months, joined RFC
Pierse: RN
Freeman: Manchester Regiment (infantry), but RFC before Aug 1914
D’Albiac: Royal Marines
Joubert: Royal Field Artillery
Barratt: Royal Field Artillery
Playfair: Royal Field Artillery
Gerrard: Royal Marines
Gordon: Royal Marines
Foster: Royal West Kent (infantry)
Baldwin: R Irish Hussars (cavalry)
Quinnell: Royal Artillery
Herbert: R Warwickshire Rgt (infantry; strictly speaking, shouldn’t be on list as retired as an Hon Air Cdre, but held important training role in mid-20s)
SW Smith: Royal Field Artillery

There are some others, but - could you tell me where this notion that the inter-war RAF was dominated by cavalry officers comes from, please? There were more Royal Marines (via the RNAS, of course) than donkey wallopers…

The issue, in part, is that the RAF had nowhere near the social cachet of the cavalry regiments, and many officers with a pre-war cavalry background ((who’d joined the RFC on attachment from their regiments, which - like the RFC- specialised in recce as it sounded interesting), had no intention of leaving the Army.

I've done an analysis of that.

There are 55 names in the list. Of which 42 were ex-Army, 10 were ex-Royal Navy and 3 were ex Royal Marines. That's 76.36%, 18.18% and 5.45%.

Royal Artillery: 12 - 28.57%
Royal Engineers: 1 - 2.38%
Infantry: 24 - 57.14%
RASC: 1 - 2.38%

Cavalry: 4 - 9.52%

There are only three glaring omissions that I can see.

• Keith Park who was ex-Royal New Zealand Artillery.
• John Slessor who went directly into the RFC and (according to Wikipedia - sorry) became an Air Commodore on 1st September 1939.
• Raymond Collishaw who went directly into the RNAS (another resort to Wikipedia that I apologise for.)

 

[NOMISYRRUC]

...the RNAS and RFC were of roughly comparable size on 1 April 1918 on formation of the RAF...

The RFC was nearly 3 times larger than the RNAS.

The RFC had 144,078 officers and men in March 1918, whereas the RNAS had 55,066 officers and men at 15th March 1918.

Therefore, in terms of personnel 72% of the RAF at 1st April 1918 was ex-RFC and 28% was ex-RNAS.

 

[NOMISYRRUC]

In Dec 1918 Coastal Area/10 Group RAF (I’m not clear about its exact designation then) had about 700 aircraft plus airships across more than 70 bases. It was, AIUI, reduced to a single shore based flying boat squadron by 1923.

For what it's worth the Metropolitan RAF was initially organised into five geographic commands. They were called "Areas" which were initially numbered one to five in Arabic numerals, that is until 8th May 1918 when they were replaced by geographic tiles as follows:

No 1 Area became the South-Eastern Area​

No 2 Area became the South-Western Area​

No 3 Area became the Midland Area​

No 4 Area became the North-Eastern Area​

No 5 Area became the North-Western Area​

Between January and October 1919 the five area commands were reduced to two (the Northern and Southern Areas) which in turn were replaced by the Inland Area on 1st April 1920. The Inland Area was renamed Training Command in May 1936.

Each of the area commands had several functional groups under its control. That is one equipment group, at least one training group and at least one operations group. There were also a few independent groups and the 6th Brigade which controlled the Home Defence units.

Initially the groups only had Arabic numbers but (Equipment), (Operations) or (Training) was added as applicable to their titles on 8th August 1918. E.g. No. 10 Group had its title changed to No. 10 (Operations) Group.

The Operations Groups controlled the ex-RNAS units and those which hadn't been disbanded by 15th September 1919 were transferred to the Coastal Area which was formed on that date. The Coastal Area was renamed Coastal Command in May 1936.

I'll have to do another post about the number of squadrons.

Source: RAFWEB

 

[BB1984]

The Breda-SAFAT gun used short-recoil and was as heavy as the big Browning. Its 12.7 x 81 round was based on Vickers' .5"V/565 - a semi-rimmed version of their 0.5-inch round (the .5V/580). One difference was the Italians developing explosive shells (technically illegal in 12.7). The explosive charge was very small but the Regia Aeronautica still put great stock in these rounds.

IIRC any explosive projectile lighter than 400g was illegal? Thus the plethora of 'weak' 37mm fast-firing cannons at the turn of the century.
Italian gun was firing at 700 rd/min, the big airborne Browning was at 600 rd/min before 1941? We also have the Belgian (FN) developments of the BMG that did above 1000 m/s by 1940, however that is a bit too late for the RAF? (paging @Tony Williams )

As Hood said, the RAF had discounted 0.5-inch calibre in 1928 - mainly because .303 was then seen as sufficient. But, according to Tony Williams, the Vickers 0.5-inch was a good performer after some bugs were worked out. If you want a 0.5-inch gun, I would say that the Vickers gun - especially firing the unrimmed .5V/580 - would be a superior candidate compared with the Breda-SAFAT.

Works for me.

If greater hitting power was desired, the .5V/565 was scaled up as the V/690 for the Vickers Class D gun. That naval gun (and its 45 inch barrel) weighed over 100 lbs. But, perhaps the Vickers 0.5-inch aircraft gun could also be scaled up to fire the same semi-rimmed 12.7 x 120 mm V/690 round?

Hmm, how about necking out either of those as much as possible? Talk 15-17-18 mm depending on what can be done, so it can fire a worthwhile HE ammo. Especially the V/690 looks promising, being so big for a 0.50.
At any rate, not waiting for the Hispano to materialize is IMO the 1st priority, so the workable heavy wepons can be installed in the fighters by 1939 in good numbers.

Tony Williams has written about this and, IIRC, his version was that the RAF considered going to .50 They tested .50 vs. .30 and decided that the .50 did not offer sufficient improvement over the .30 to be worthwhile; that's when the RAF decided to go to 20mm. Tony also had a lot of analysis vindicating this decision. I am more "pro .50" than Tony, but see the logic.

My opinion is that if you have a working, high performance 20mm (e.g., the debugged Hispano) and planes big and powerful enough to carry it, then there's not a lot of argument for .50 On the other hand, if you have difficultly with either of those two things, then a compact, light weight .50 (e.g., the MG131) is very useful and a heavy .50 (in 12.7x99mm, 12.7x108mm, or especially in higher velocity loadings like the Vickers D, 14.5×114mm, or the stillborn US .60) is a good "I'll use this till I get my 20mm working" approach, especially for fighter to fighter combat.

 

[Tony Williams]

The Breda-SAFAT gun used short-recoil and was as heavy as the big Browning. Its 12.7 x 81 round was based on Vickers' .5"V/565 - a semi-rimmed version of their 0.5-inch round (the .5V/580). One difference was the Italians developing explosive shells (technically illegal in 12.7). The explosive charge was very small but the Regia Aeronautica still put great stock in these rounds.

IIRC any explosive projectile lighter than 400g was illegal? Thus the plethora of 'weak' 37mm fast-firing cannons at the turn of the century.
Italian gun was firing at 700 rd/min, the big airborne Browning was at 600 rd/min before 1941? We also have the Belgian (FN) developments of the BMG that did above 1000 m/s by 1940, however that is a bit too late for the RAF? (paging @Tony Williams )

As Hood said, the RAF had discounted 0.5-inch calibre in 1928 - mainly because .303 was then seen as sufficient. But, according to Tony Williams, the Vickers 0.5-inch was a good performer after some bugs were worked out. If you want a 0.5-inch gun, I would say that the Vickers gun - especially firing the unrimmed .5V/580 - would be a superior candidate compared with the Breda-SAFAT.

Works for me.

If greater hitting power was desired, the .5V/565 was scaled up as the V/690 for the Vickers Class D gun. That naval gun (and its 45 inch barrel) weighed over 100 lbs. But, perhaps the Vickers 0.5-inch aircraft gun could also be scaled up to fire the same semi-rimmed 12.7 x 120 mm V/690 round?

Hmm, how about necking out either of those as much as possible? Talk 15-17-18 mm depending on what can be done, so it can fire a worthwhile HE ammo. Especially the V/690 looks promising, being so big for a 0.50.
At any rate, not waiting for the Hispano to materialize is IMO the 1st priority, so the workable heavy wepons can be installed in the fighters by 1939 in good numbers.

Tony Williams has written about this and, IIRC, his version was that the RAF considered going to .50 They tested .50 vs. .30 and decided that the .50 did not offer sufficient improvement over the .30 to be worthwhile; that's when the RAF decided to go to 20mm. Tony also had a lot of analysis vindicating this decision. I am more "pro .50" than Tony, but see the logic.

My opinion is that if you have a working, high performance 20mm (e.g., the debugged Hispano) and planes big and powerful enough to carry it, then there's not a lot of argument for .50 On the other hand, if you have difficultly with either of those two things, then a compact, light weight .50 (e.g., the MG131) is very useful and a heavy .50 (in 12.7x99mm, 12.7x108mm, or especially in higher velocity loadings like the Vickers D, 14.5×114mm, or the stillborn US .60) is a good "I'll use this till I get my 20mm working" approach, especially for fighter to fighter combat.

A few points:

The St Petersburg Declaration of 1868 banned explosive or incendiary projectiles weighing less than 400g. However, during WW1 extensive use was made of such bullets, primarily to deal with hydrogen-filled balloons and airships. After the war, this issue was considered at an international legal convention which recommended that the restriction should be removed for aircraft, or anti-aircraft, armament. This was never formally ratified but everyone thereafter behaved as if it had been.

I have no information about the reliability of the .5" Vickers aircraft gun - it saw virtually no use - but I understand that the land AFV version was troublesome. The export (semi-rimmed) version of the .5" ammunition was used in Japanese (Ho-103) as well as Italian guns plus an obscure twin-barrel engine-driven gun, the Hungarian Gebauer GKM.

The big high-velocity .5" Vickers Class D saw very limited use by some Far East armies in the AA role. It was slow-firing (c.400 rpm) and really not worth the bother.

The RAF's view that .5" guns were not worth the extra weight and reduced rate of fire over .3" guns (since without explosive shells all they did was make a slightly bigger hole) was formed at the beginning of the 1930s when combat aircraft were very flimsy. The RAF did realise that planes would become tougher and harder to shoot down so something better than .303" would be needed, but in that case 20mm firing explosive shells would be superior to any .5". This reasoning was basically correct but the Hispano proved problematic and was not ready when it was needed most, in the BoB. IMO the thoroughly developed and tested Oerlikon guns would have been better - probably the 20x101RB FFL.

 

[HoHun]

The RAF's view that .5" guns were not worth the extra weight and reduced rate of fire over .3" guns (since without explosive shells all they did was make a slightly bigger hole) was formed at the beginning of the 1930s when combat aircraft were very flimsy. The RAF did realise that planes would become tougher and harder to shoot down so something better than .303" would be needed, but in that case 20mm firing explosive shells would be superior to any .5". This reasoning was basically correct but the Hispano proved problematic and was not ready when it was needed most, in the BoB. IMO the thoroughly developed and tested Oerlikon guns would have been better - probably the 20x101RB FFL.

Hi Toni,

Did the British ever consider the US M2 12.7 mm gun as thr basis for a 20 mm cannon? Seems they were fully committed to the 20 mm Hispano, but I wonder if they had any fall-back plans.

Regards,

Henning (HoHun)

 

[Desertfox]

Westland can make 1000 Spitfires, each with 2 cannons, for the same investment of 1000 Merlins and 2000 cannons.

Question is, how good could Merlin Whirldwinds be in the anti-bomber role. That massed cannon firepower would have made short work of any German bomber, and the Whirlwinds would likely be fast enough to avoid the escorts, unlike the Me110s.

 

[HoHun]

Hi Desertfox

Westland can make 1000 Spitfires, each with 2 cannons, for the same investment of 1000 Merlins and 2000 cannons.

Question is, how good could Merlin Whirldwinds be in the anti-bomber role. That massed cannon firepower would have made short work of any German bomber, and the Whirlwinds would likely be fast enough to avoid the escorts, unlike the Me110s.

Considering how well the Hurricanes did despite their low speed, I'd think even the Kestrel Whirlwind if used in numbers during the Battle of Britain would have made quite an impact.

Regards,

Henning (HoHun)