AHC: AM's/RAF's best reply to LW and Heer in 1940

On Cannon! Specifically the HS-404 there is several PODs that can allow for the gun to be more reliably in service for 1940 and the gun is needed over .30, .303 and .50 calibre weapons

Firstly - an earlier 'purchase' of the licences and all the drawings from the respective licensees (which was grudgingly eventually done) including where necessary from Oerlikon so they are not waiting for Martin Baker to reinvent the wheel with regards to reliable feeding issues

For example the Original HS 404 the British were using had a very long barrel due to the intention of it being a 'Motor Canon' that fired through the Prop hub (which was above the line of the crank shaft via a gearbox see pic below)

3036_116_307-dewoitine-501.jpg


Now an earlier realisation that wing mounted or nose mounted (in the case of twin engined ac) guns in RAF did not need to have such a length of barrel would also benefit the weapons reliability and production - instead the extra length barrel was persevered with until the mid war MK V Cannon was developed.

Machine guns such as the Browning .303 were very good guns - exceptional rate of fire and only weighed 10 Kgs each - however it was already known that the rifle calibre bullets were not very good at damaging aircraft sufficiently to shoot them down (hence the shift to 4 and then 8 guns pre war with a further attempt to later shift to 12 when issues with the cannon got bottoms wobbling!) and that a shift to .50 cal was not enough to justify the extra weight in gun and ammo while a 20mm weapon such as the HS 404 despite being even heavier in terms of weapon and ammo and larger etc brought a very powerful and effective round/shell was worth the weight hit. So long as it worked.

Now I can already hear the furious typing of retorts along the lines of 'But the US managed just fine with the Ma Deuce damn your eyes and the 20mm was too unreliable' - but they didn't and the last bit is only true of US cannon - what happened is that they muddled through in spectacular fashion with the AN/M2 and if they could have reliably replaced it with the HS404 - they would have done in the blink of an eye and the USN and USAAF would very likely had performed even better.

In his great work on all things machine guns etc, Col. Chin USMC (who championed the gun in USN service and did everything he could to make the system work and must have felt like Sisyphus doing so) explains that by 1941 the US had produced something like 100,000 HS 404s - well made weapons with a superb finish - that sadly did not work due to US interpretation of the necessary headspace issues resulting in the head spacing being 1/8th Inch too great and resulting in light strikes making the gun far too unreliable. Later production after listening to the feedback from the US Ammunition companies and the British reduced the head spacing issue to 1/16 - so sort of met them half way! It was one of the few black marks against a US industry in WW2 - considering how the USA went from 'not really producing weapons' in 1939 to building as many as everyone else by 1944 - and almost universally building them better it is only surprising that it did not happen more often. But it did mean that only the USN used them in WW2 with the glaring exception of the Lightning which overcame the Light strike issues with field mods and an electrical recocking mechansim and in the tail gun of the B29. And there was no plan B - the British also had no plan B but got their version of the gun to work reliably in 1941 and so were able to arm their fighters with the 20mm cannon - the US did not really overcome the issues and so soldiered on with the otherwise excellent .50. In fact reliability issues continued into the late 40s and the F86D was famously still armed with a brace of 6 x .50 cals - everyone else was using cannon (the Russian MIG 15s were using 23mm and 37mm!)

Everyone else went cannon for a reason and the HS404 particularly the British Mk V Hispano was by most bench marks the best of the WW2 aircraft cannon.

So in conclusion any and all effort must be made to bring this weapon system into operation earlier.
 
On Merlin and the Ramp head.

The Ramp Head issues (please read the link and the rest will make more sense!) that dogged earlier Merlins probably delayed development of the type by 'possibly' up to 2 years - so an earlier change away from the 'ramp head' Merlin or even better Albert George Elliott never works for RR and does not 'inflict' his obsession of this untested feature on the early merlin from 1934 without any thought to parallel development of a Merlin without Ramp Head.

The other change would be for RR to be 'less dismissive' regarding the use the Wet liner of the Curtiss D12 engine (which they were shown in 1924) and not instead build the Kestrel with a dry liner which caused all sorts of issues - while they did later change to a wet liner the legacy of the design caused all sorts of issues.

So a better Kestrel and a better Buzzard and then a better 'non-ramp head' Merlin

Ta Da - improved Merlin and general RR development by 1940
 
One thing that has to change is the RAF has to get over its allergy to dive bombing. I suppose this was because they viewed dive bombing as a gateway drug to the RAF getting pulled back into the Army's orbit or something. It's ironic that the Germans had the exact opposite reaction with the ridiculous requirement that all bombers (even four engine ones) had to have dive bombing capability.

The RAF's problems in this area are highlighted in one Peter Smith's books on dive bombing where he talked commanders telling Vultee Vengeance pilots in Burma to level bomb instead of dive bombing (they dive bombed and they did it well).

We can propose Skua, Henley, a biplane, and/or something like Vindicator, Stuka, or a twin engined job. Shortcoming of most of dive bombers was their low speed, so Henley looks to me as the best bet, supposedly doing close to 300 mph. Making a dive bomber from a fighter also looks good to me. Like a spin off from a Gloster monoplane fighter, or something along IMAM Ro.57 (+ British have better engines than Italians).
Even with RAF against it, the Army should probably embrace them with both hands.

...
Now I can already hear the furious typing of retorts along the lines of 'But the US managed just fine with the Ma Deuce damn your eyes and the 20mm was too unreliable' - but they didn't and the last bit is only true of US cannon - what happened is that they muddled through in spectacular fashion with the AN/M2 and if they could have reliably replaced it with the HS404 - they would have done in the blink of an eye and the USN and USAAF would very likely had performed even better.

USN was of opinion that 1 Hispano II was equal to 3 .50 BMGs, them and USAAF were trying and installing them on fighters - P-51, P-38, P-61, F6F, F4U, F7F etc. Even as underslung pair for P-47s, that certainly was not lacking in gun firepower.

Everyone else went cannon for a reason and the HS404 particularly the British Mk V Hispano was by most bench marks the best of the WW2 aircraft cannon.
So in conclusion any and all effort must be made to bring this weapon system into operation earlier.

Hisso V have had very good RoF, MV and shell weight, some were offering much lighter weigth (B-20, Ho-5) and ability to fire synchronised.
An easy effort to bring a 20mm cannon for the RAF will be avoiding the Hispano cannon.
 
Hisso V have had very good RoF, MV and shell weight, some were offering much lighter weigth (B-20, Ho-5) and ability to fire synchronised.
An easy effort to bring a 20mm cannon for the RAF will be avoiding the Hispano cannon.

The problem with your 2 examples is that they are not designed until much later in the war - the B-20 while excellent and light weight entered production in 1944 and I believe that the Ho-5 was designed/entered production even later in 1945 - I have no idea if these weapons were as reliable or as good as the HS404 only that the then very mature MKV out lasted them both.

HS-404 was already designed built and mounted on aircraft in 1939 with many of the subsequent extras such as improved feed mechanisms already in development for the British to build on and the design was available!

Had more treasure and time been thrown at it earlier it is easy to conceive of a reliable cannon armed Hurricane and even a partially cannon armed Spit and for less .303 bullet ridden LW Bombers managing to return to France as a result!

Firing synchronized ie firing through the propellor arc was not an issue for the British as they dropped the requirement for such a system before the war for their new fighters reasoning that on a 2 blade prop the drop in ROF inflicted by the interruption gearing was already too much and would only get worse on a 3 or 4 blade propeller - with the understanding that a fighter pilot would get no more than a 2 second burst they had to get as many bullets at the target as possible - also there was the extra weight of the interrupter gear and the position of such weapons in the cowl forward of the COG added issues and took longer than wing guns to rearm and service.

Lastly I seem to recall that the arrangement of the Merlin and similar Engines with the position of the supercharger and fuel tanks located between the Engine and Cockpit was such that it would have been difficult to fit cowl guns and the interrupter gear.
 
...

Ta Da - improved Merlin and general RR development by 1940

About Merlins and other engines. Yes, avoiding the ramp-head mistake would've probably improved quantity of reliable Merlins already by late 1930s. Here, I'd propose RR canncelling Exe, Peregrine and Vulture, while developing and producing military version of the 'R' engine. Hopefully we'd get reliable 1300+ HP on 87 oct, 1500-1600 on 100 oct for 1940? Spitfires as 1st installation.
Hercules might be a good fit on Henley.

The problem with your 2 examples is that they are not designed until much later in the war - the B-20 while excellent and light weight entered production in 1944 and I believe that the Ho-5 was designed/entered production even later in 1945 - I have no idea if these weapons were as reliable or as good as the HS404 only that the then very mature MKV out lasted them both.

HS-404 was already designed built and mounted on aircraft in 1939 with many of the subsequent extras such as improved feed mechanisms already in development for the British to build on and the design was available!

Hold your horses :)
HS-404 is not Hispano V (800 rpm), but Hispano I (600 rpm, 10 kg heavier than Mk. V). The Mk.V was 1st installed on Tempests, Spring 1944.
Japanese cannon was discontinued due to the small, unimportant thing of Japanese loosing the war ;)
Soviets moved on at 23 and 37mm from 1945 on.

Had more treasure and time been thrown at it earlier it is easy to conceive of a reliable cannon armed Hurricane and even a partially cannon armed Spit and for less .303 bullet ridden LW Bombers managing to return to France as a result!

British Hispano project alread went very fast historically. Quirk is that both Germans and French have had a head start by 2 years at least, mainly by purchasing licence abroad early enough. End result being that RAF have had just a token number of cannons by BoB, unlike the other two countries.

Firing synchronized ie firing through the propellor arc was not an issue for the British as they dropped the requirement for such a system before the war for their new fighters reasoning that on a 2 blade prop the drop in ROF inflicted by the interruption gearing was already too much and would only get worse on a 3 or 4 blade propeller - with the understanding that a fighter pilot would get no more than a 2 second burst they had to get as many bullets at the target as possible - also there was the extra weight of the interrupter gear and the position of such weapons in the cowl forward of the COG added issues and took longer than wing guns to rearm and service.

Granted, not having ability to fire synchronised is not an automatic disqualifier (I've proposed Oerlikons for RAF, those will not synchronise). However, having a wepon A that can do it vs. a wepon B that can't will score points for a wepon A, not B. Synchronised wepons don't require installation under the cowling, and people were installing wepons close to the CoG already.

Lastly I seem to recall that the arrangement of the Merlin and similar Engines with the position of the supercharger and fuel tanks located between the Engine and Cockpit was such that it would have been difficult to fit cowl guns and the interrupter gear.

Choice of engine does not dictate placement of fuel tanks. V-1710 and VK-105 certainly allowed for synchronised guns, their S/Cs being on same location as that of the Merlin.
 

SwampTiger

Banned
Rather than Defiant fighter bomber, as probably too early for concept, develop a dive bomber variant, with bomb crutch, replace turret with flexible mount and add dive brakes. A few more gallons of fuel would help.
 
Basically, a good boy's counterpart to the best possible LW topic. It should also include aircraft operated by British Army, so we're also to give them as good gear and doctrine as realistically possible.
Before we jump into bits and pieces that warm the rivet-counter's hart, a good look at doctrine, training, communication, cooperation and defence of assets is needed. Change the historical RAF/AM doctrine when/where needed.
Also - how much of assets to deploy in France before April/May 1940? What to deploy?
Realistic pieces of gear are encouraged (no jets, no cluster bombs etc), buy/licence from abroad if need.
Start date is January 1936, and we somehow know that war is imminent within 3-4 years.
Extra points for managing to save France in 1940, so we need to blunt both LW and Heer with air power - tall order indeed.

I think cluster bombs of some sort are definitely possible with 1939 tech. The Soviets were dropping early incindiary cluster bombs on the Finns during the Winter War. The tech existed it just needed someone to apply what was already out there.

Though even if we accept that cluster bombs are not possible Lazy Dogs certainly are.

https://en.m.wikipedia.org/wiki/Lazy_Dog_(bomb)
 
I think cluster bombs of some sort are definitely possible with 1939 tech. The Soviets were dropping early incindiary cluster bombs on the Finns during the Winter War. The tech existed it just needed someone to apply what was already out there.

Though even if we accept that cluster bombs are not possible Lazy Dogs certainly are.

https://en.m.wikipedia.org/wiki/Lazy_Dog_(bomb)

There is also good old fashioned daisy cutters which were really nothing more than wrapping razor wire around standard GP bombs.
 
the .60 in cannon went nowhere for ww2 needs. M3 .50 was too late developed for ww2
The Ordinance guys working on MGs and Cannons were just a terrible bunch, every bit as bad as the Torpedo Mafia over at NTS

They screwed up almost everything they touched. Lead paint chips most have been required dining.

The Japanese were able to upscale the basic .30 Browning all the way upto 30mm, and the US wasted the entire war on necking down the 1.1" to .60 caliber
 
I think cluster bombs of some sort are definitely possible with 1939 tech. The Soviets were dropping early incindiary cluster bombs on the Finns during the Winter War. The tech existed it just needed someone to apply what was already out there.

Though even if we accept that cluster bombs are not possible Lazy Dogs certainly are.

https://en.m.wikipedia.org/wiki/Lazy_Dog_(bomb)

https://books.google.com/books?id=9y21CwAAQBAJ&pg=PA12

extended bomb fuzes on 50kg bombs for Stukas
 
Some other possibilities for the RAF, on technology of the day.
- pre-Mosquito. Bomber, 4x500 or 2 x 1000 lbs in bomb bay, Merlin X, hopefully 330-350 mph
- a tiny 2-engined fighter-bomber, or dive-bomber, or heavy fighter. Size of Whirlwind or Ro.57. Mercury engine, a wepon bay that can hold up to 1000 lb bomb or a gun pack with 4 HMGs or two cannons, plus 4 HMGs or 2 cannons fixed. 300-320 mph
- monoplane Gladiator. Mk.I with fixed U/C, 6 LMGs, sorta Ki-27 or Fokker D.XXI; Mk.II with upwards-retractable & strong U/C, 300 mph, able to dive-bomb with 500 lb bomb, for Army mostly; Mk.III with Taurus, 320-330 mph for Army; Mk.V with Merlin XII for RAF, 360 mph, 4 HMGs.
- Defiant fighter-recon/tank buster; no turret, rear gunner in streamlined post with 1 HMG, 2 cannons in wings, for Army, 320 mph
- 4 engined bomber by A-W instead of Whitley
 

Deleted member 1487

- a tiny 2-engined fighter-bomber, or dive-bomber, or heavy fighter. Size of Whirlwind or Ro.57. Mercury engine, a wepon bay that can hold up to 1000 lb bomb or a gun pack with 4 HMGs or two cannons, plus 4 HMGs or 2 cannons fixed. 300-320 mph
You mean the Whirlwind in FB configuration. No need for a weapons bay, the point of a fighter-bomber is to be a fighter with some bombing abilities. The FW187 dive bomber/ground attack version that Focke-Wulf proposed IOTL and Anthony Williams also suggested is a good model for what the Whirlwind could do with a similar effort; the FW187 book I got compared the particulars of the two aircraft and they were quite similar, so if it would work for the 187 the Whirly should be able to too.
Edit: NVM the Whirlibombers were already an OTL thing.
https://en.wikipedia.org/wiki/Westland_Whirlwind_(fighter)#Operational_history
From 24 October until 26 November 1943, Whirlwinds of 263 Squadron made several heavy attacks against the German blockade runner Münsterland, in dry dock at Cherbourg. As many as 12 Whirlwinds participated at a time in dive bombing attacks carried out from 12,000–5,000 ft (3,700–1,500 m) using 250 lb (110 kg) bombs. The attacks were met by very heavy anti-aircraft fire, but virtually all bombs fell within 500 yd (460 m) of the target; only one Whirlwind was lost during the attacks.

The radial engine is both unnecessary and really not desireable, as it is really not significantly more resistant to bullets as the liquid cooled inlines in non-fuselage mounting (see HS129 for plenty of examples of that), while and with it's wider frontal area and greater drag would hurt aerodynamics and speed. The FB Mosquito worked just fine if not even much more than just fine even with liquid cooled engines. A Whirlwind with HS-12Y/45 engines would be just as good if not better than the historical engine given the upgrades it was getting, it's greater power, and the fact that it was already well developed as an engine and didn't have the Peregrine's problems.
 
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You mean the Whirlwind in FB configuration. No need for a weapons bay, the point of a fighter-bomber is to be a fighter with some bombing abilities. The FW187 dive bomber/ground attack version that Focke-Wulf proposed IOTL and Anthony Williams also suggested is a good model for what the Whirlwind could do with a similar effort; the FW187 book I got compared the particulars of the two aircraft and they were quite similar, so if it would work for the 187 the Whirly should be able to too.

The radial engine is both unnecessary and really not desireable, as it is really not significantly more resistant to bullets as the liquid cooled inlines in non-fuselage mounting (see HS129 for plenty of examples of that), while and with it's wider frontal area and greater drag would hurt aerodynamics and speed. The FB Mosquito worked just fine if not even much more than just fine even with liquid cooled engines. A Whirlwind with HS-12Y/45 engines would be just as good if not better than the historical engine given the upgrades it was getting, it's greater power, and the fact that it was already well developed as an engine and didn't have the Peregrine's problems.

I was trying to get more on the 'bomber' side of equation, thus the proposal for a weapons bay. As a pure fighter, the HS-12Y-powered, but otherwise OTL Whirly is certainly a better thing.
A 500 kg bomb was slowing down the Ro.57 by 35 km/h - from 466 to 431 km/h, or some 8% (all max speed figures). So we'd see a bombed-up ALT Whirly with V12 engines doing perhaps 520 km/h instead of 560+ km/h?
Reason why I've proposed Mercury engines is because we should be getting a surplus of those, since neither Lysander nor Blenheim are up to the task for 1940, so a major wind-down is in order for production of those A/C. A small 300+ mph dive-bomber or fighter-bomber will stand much better chances, but even then an escort will be needed.
On the other hand, a V12 powered dive bomber, size of Whirly, with wepons bay, might do 550 km/h...
 
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