Alternative British Army AVF 1930-40s

[NOMISYRRUC]

One big problem will be convincing the RA gunners that a SPG is worth it. As they will see that one SPG equals the cost of 6 25lber's. It only changed because of manpower shortages. To many going to air defence units.. regards

One battery of the Experimental Mobile Force's artillery brigade was equipped with an SPG called the Birch Gun, which was an 18pdr mounted on an A2 Medium Mk II tank chassis.

IIRC the concept wasn't developed for 3 reasons.

1) The cost;
2) Hostility from the RTC, which though the guns of its "proper" tanks could do the job. I think it also thought that it heavier artillery was needed the "Royal Tank Artillery" should be a branch of the RTC and not a branch of the RA. They won this argument because a proportion of the infantry and cruiser tanks were fitted with 3.7" howitzers for the close support artillery role;
3) The 18pdr gun was used to provide direct fire in the close support role and the RTC's assertion that this was their job won the argument. It might have been different if the Birch Gun had been fitted with a heavier (and more versatile) gun like the 18/25pdr or 25pdr. However, those weapons weren't around at the time and they can't be in an alternative timeline without spending more money.

At about this time the RA was mechanising its heavy and medium artillery. The prime movers for the guns were full-track tractors called Medium Dragons, some of which were based on the A2 Medium Mk I and II tanks.

It also had a handful of mechanised field artillery brigades, whose 18pdr guns and 4.5" howitzers were towed by full-track tractors called Light Dragons. Some of them were part of the family of vehicles that included the A4 Light Tanks and Carriers.

Note that a Royal Artillery brigade is not the same level of command as an infantry brigade or cavalry brigade. It was equivalent to a British infantry battalion or cavalry regiment and like them was a colonel's command. The RA brigades were renamed regiments in 1938 as part of a reorganisation of the regiment and also to avoid the confusion it caused.

 

[Mike D]

The RA brigades were renamed regiments in 1938 as part of a reorganisation of the regiment and also to avoid the confusion it caused.

So the Regiment's brigades became the Regiment's regiments and continued serving alongside the regiments of other Corps as part of the Army's brigades to reduce confusion?

 

[NOMISYRRUC]

So the Regiment's brigades became the Regiment's regiments and continued serving alongside the regiments of other Corps as part of the Army's brigades to reduce confusion?

Correct!

I think it would have been better English if it was 1st Field Battalion, Royal Regiment of Artillery, rather than 1st Field Regiment, Royal Regiment of Artillery. That would have fitted in historically too, because the Royal Artillery was organised into battalions and companies before the 1890s. IIRC the word battery originally meant where a group of guns was positioned, but eventually came to become the collective term for an artillery unit analogous to a company of infantry and squadron of cavalry.

A similar thing happened in 1939 when the battalions of the Royal Tank Corps became regiments of the Royal Tank Regiment. For example, the 1st Battalion, Royal Tank Corps became the 1st Royal Tank Regiment. However, the RTC became the RTR because it was merged with the cavalry to create the Royal Armoured Corps (RAC). The RTC had to become the RTR or it would have been a corps within a corps and the battalions became regiments to conform with the cavalry which was organised into regiments.

Prior to the late 1940s the Corps of Royal Engineers was organised into companies, which were anologous to artillery batteries, infantry companies and cavalry squadrons.

Usually there weren't enough companies to organise them into larger formations, which is probably why the accounting unit for the RE was the company. The RE companies in an infantry division reported to the Commander Royal Engineers (CRA) who was a colonel (similarly the artillery brigades/regiments reported to a Commander Royal Artillery (CRA)). However, there were a few RE battalions at corps level or higher. For example the RE was forming its own tank battalions at the end of World War I.

After the war the companies became squadrons, probably because squadron sounds better than company. Furthermore the squadrons were organised into regiments, which became the accounting unit for the RE. Again I think battalion would have suited better than regiment, but regiment sounds better.

 

[Gunnarnz]

So the Regiment's brigades became the Regiment's regiments and continued serving alongside the regiments of other Corps as part of the Army's brigades to reduce confusion?

Yes, that's right. The Regiment's regiments became the Brigade regiments of other regiments, except where they were brigades in and of themselves and cooperated as part of the Regimental Artillery Group. The Brigades of course had their own regiments, dating back to the introduction of the regimental system, and the Regiment's regiments shared this system while they were brigades and even after they became regiments (although of course part of the regiment could be in other brigades). It just made things so much simpler.

 

[NOMISYRRUC]

So the Regiment's brigades became the Regiment's regiments and continued serving alongside the regiments of other Corps as part of the Army's brigades to reduce confusion?

Normally a brigade of the British Army consisted of one type of formation so there were cavalry and infantry brigades under brigadiers. Therefore the old style artillery brigades seemed to be much larger and more powerful to people that didn't know better.

At the start of infantry division in World War I consisted of 3 infantry brigades commanded by a brigadier. Each infantry brigade had 4 infantry battalions under a colonel.

However, there were also 12 Royal Field Artillery batteries commanded by majors, which were organised into 4 brigades commanded by colonels. There was also a battery of heavier guns which belonged to the Royal Garrison Artillery (RGA). [The Royal Regiment of Artillery was abolished in 1899-ish and replaced by independent Royal Regiments of Field, Garrison and Horse Artillery until they were reunified in 1922-ish.] The 3 RFA brigades and the RGA battery reported to a Commander Royal Artillery (CRA) who was a brigadier at the division's headquarters.

At the start of World War II an infantry division still had 3 infantry brigades, but there were only 3 battalions per brigade. The 3 RFA, brigades were replaced by 3 field regiments, RA plus an anti-tank regiment, RA and a light anti-aircraft regiment, RA reporting to the CRA.

There were also brigade groups, which were infantry and armoured brigades with their own, armour, artillery, engineers and administrative units.

For example the Experimental Mechanised Force was an armoured brigade group in all but name. I consisted of a number of RTC battalions, plus a battalion of motorised infantry, a brigade of motorised artillery and a motorised field engineer company. If it had been the Experimental Mechanised Brigade it would have been an armoured brigade with a brigade of artillery.

 

[NOMISYRRUC]

So the Regiment's brigades became the Regiment's regiments and continued serving alongside the regiments of other Corps as part of the Army's brigades to reduce confusion?

And there was the Rifle Brigade, which was actually an infantry regiment. So the 1st Rifle Brigade was an infantry battalion, not an infantry brigade equipped with rifles instead of muskets.

 

[Mike D]

Prior to the late 1940s the Corps of Royal Engineers was organised into companies, which were anologous to artillery batteries, infantry companies and cavalry squadrons.

It always confused me why we (Royal Corps of Signals) had Squadrons after coming from the RE, who had Companies (at the time).

Yes, that's right. The Regiment's regiments became the Brigade regiments of other regiments, except where they were brigades in and of themselves and cooperated as part of the Regimental Artillery Group. The Brigades of course had their own regiments, dating back to the introduction of the regimental system, and the Regiment's regiments shared this system while they were brigades and even after they became regiments (although of course part of the regiment could be in other brigades). It just made things so much simpler.

Of course. You can see how complicated the previous system was compared to that

 

[marathag]

Could the Culverin and Cutlass have been adapted as tank engines? If so could it have been done in time for them to be built in place of the Liberty, Meteor and Meteorite? And if both of those were possible would they have been better than the Liberty, Meteor and Meteorite?

Biggest problem, was that Culverin was large.

As in very tall, almost 15" taller than the Wright R-973 used in the Lee and Sherman, and 5" more than the Wright G-200 used in the M6 Heavy tank

 

[riggerrob]

Wow!
... and the Wright-Continental R-975 engine was already 45 inches in diameter! The radial engine's diameter was only part of the reason Sherman's had such deep hulls. The other reason was that the Sherman's drive shaft went straight forward, from the centre of the engine to the front differential. This simplified the rapidly-spinning drive shaft, but required raising the turret floor.

 

[Simon]

Theoretically the Merlin aero engine could be developed into the Meteor and Meteorite about 5 years earlier.

Five years? Seems a little early. As I understood things the first Merlin engines were coming off the production lines in July of 1938 with the Meteor taking six months to develop once the project was started. That's in wartime though, I'd expect peacetime development to not be as rushed so double that to say a year? That gets you to mid-1939 but then you have to set up the production lines to actually make the things. Three/three-and-a-bit years seems to most that you could reasonably move the engine up I would have thought.

As I said on another thread technically there was nothing stopping the British from building something like the A34 Comet from the early- to mid-1940s provided that they made the right choices. They already had the Merritt-Brown gearbox and Horstmann suspension, sloped armoured had been mentioned in General Staff specifications back in 1938, the 6-pounder gun had been proposed in 1937 only to be put on hold but took just six months to develop when decided upon, and the Meteor engine likewise took six months to develop from start to testing in a tank. Too late for France but North Africa could be very different.

 

[sonofpegasus]

realistically what horse power would a Meteor type version of the 1936 specification Kestral achieve on army grade petrol?

 

[NOMISYRRUC]

Five years? Seems a little early. As I understood things the first Merlin engines were coming off the production lines in July of 1938 with the Meteor taking six months to develop once the project was started. That's in wartime though, I'd expect peacetime development to not be as rushed so double that to say a year? That gets you to mid-1939 but then you have to set up the production lines to actually make the things. Three/three-and-a-bit years seems to most that you could reasonably move the engine up I would have thought.

The first Merlin powered aircraft to go into service was the Fairey Battle. According to Putnams Aircraft of the Royal Air Force since 1918 the Battle first entered service in May 1937 with No. 63 Squadron. It also says that just over a year later the Battle equipped about 15 squadrons of Bomber Command.

The first A27M prototype appeared in 1942, which is why I said that the Meteor could theoretically have been produced about 5 years earlier.

The production lines that were set up to build the Liberty IOTL are instead set up to build the Meteor or different ones are set up under Rolls Royce or Rover management.

 

[Aber]

Yes, that's right. The Regiment's regiments became the Brigade regiments of other regiments, except where they were brigades in and of themselves and cooperated as part of the Regimental Artillery Group. The Brigades of course had their own regiments, dating back to the introduction of the regimental system, and the Regiment's regiments shared this system while they were brigades and even after they became regiments (although of course part of the regiment could be in other brigades). It just made things so much simpler.

And the British also developed the habit of swapping Brigades between Divisions, so the Germans had a problem keeping an accurate count of the OOB.

 

[marathag]

The other reason was that the Sherman's drive shaft went straight forward, from the centre of the engine to the front differential. This simplified the rapidly-spinning drive shaft, but required raising the turret floor.

The M18 Hellcat used the R-973, but had a lower height, had a reduction gear on the output shaft to lower it in the hull, unlike the M3/M4

 

[marathag]

realistically what horse power would a Meteor type version of the 1936 specification Kestral achieve on army grade petrol?

The Soviet M-17, based on the BMW VI, so of similar vintage, did 500HP
in the BT series.

But it ran higher octane, and over twice the displacement and ran on 6.0:1 compression. The Liberty was 5.4:1, and the Tank Kestrel would be similar.

The Liberty had +400 cubic inches over the Kestral, and in tank trim did 340HP on 63 octane.

My guess, 280-310HP, but far more reliable than the Liberty

 

[Simon]

The first Merlin powered aircraft to go into service was the Fairey Battle. According to Putnams Aircraft of the Royal Air Force since 1918 the Battle first entered service in May 1937 with No. 63 Squadron. It also says that just over a year later the Battle equipped about 15 squadrons of Bomber Command.

Hhmm, looks as though you could be right. Which is odd as going from memory I was fairly sure that the 1938 date I had was from one of Rolls-Royce's own published histories, will have to investigate further when I get the chance.

 

[yulzari]

Whilst we have the model of OTL Rover Meteor the 210bhp GMC diesel fitted to the last Valentines was quite adequate for the chassis so perhaps we should be looking for something in the 250bhp class rather than 600bhp. Perhaps the De Havilland Gipsy Six or Gypsy Queen, the Napier Rapier or Armstrong Siddeley Cheetah could be 'motorised' to fit a Valentinish chassis?

 

[Simon]

Realistically what horse power would a Meteor type version of the 1936 specification Kestrel achieve on army grade petrol?

Rolls-Royce apparently looked at both the Kestrel and the Merlin to develop into a tank engine but decided to go with the Merlin as whilst the Kestrel was smaller making it easier to fit 'On the low grade fuel available, the Kestrel would only develop about 475 bhp, and this would not provide sufficient performance in a 30-ton tank' according to the history of Rolls-Royce The Magic of a Name by Peter Pugh. That was of course in the early 1940s after a decade of further development from what it first started out as.

So what could they possible expect to achieve at the beginning of the 1930s? This is all back of the envelope guesstimate work so take it as you will. At around the time Rolls-Royce started looking at developing the Merlin into a tank engine it was producing roughly 1,000 hp with the Meteor initially producing 550 hp before being nudged up to 600 hp using pool petrol in its final configuration so lets take that 55-60% figure as a rule of thumb even if it looks to be a little conservative. In the early 1930s the Kestrel was producing around 600 hp so that gives us say 330 hp or 360 hp, which on the surface might not be all that much of an improvement considering the Nuffield Liberty eventually produced 340 hp. There would however be a number of advantages. It would be cast-block as opposed to the Liberty's steel cylinders which were screwed on and apparently a major pain when maintaining the engine, the Liberty used a chain drive in an oil bath to power its auxiliary systems which had a tendency to break at high speeds or get completely clogged with dust and dirt, one of them was the cooling system which used up roughly 20% of the engine's horsepower to run - in comparison the Meteor which took up only half that so one would hope/assume that Rolls-Royce would do a similarly decent job with the Kestrel, the Liberty needed to be tuned within an inch of its life to reach its final maximum output of 340 hp which made it ever more temperamental and prone to breaking down. The other major advantage of course is that if they'd already successfully developed an aero engine into a tank engine then the Army and Rolls-Royce would be looking at potentially turning the Merlin into the Meteor that much sooner than our timeline.

 

[RLBH]

I've toyed with the Land Kestrel before; it's not a world-beating engine on the numbers, but it's a heck of a lot better than a Liberty. And of course it has some development potential, whilst the Liberty was pretty much at the end of the line.

Sadly, though, a decent engine is just one thing that needs fixing to give the British Army decent tanks: a Crusader with 475 reliable horsepower is probably a hell of a drive, but it's no good if it's got a 2pdr AT gun and poor doctrine.

All fixable, of course...

The other major advantage of course is that if they'd already successfully developed an aero engine into a tank engine then the Army and Rolls-Royce would be looking at potentially turning the Merlin into the Meteor that much sooner than our timeline.

Idle speculation: is a Griffon adapted for tank/traction use (figure about 1,000-1,200 hp) any use for anything?

 

[Sior]

https://en.wikipedia.org/wiki/Napier_Lion



The RAF sold all their stock of Napiar Lion engines as scrap in the mid 1930's!

XIA1928580 bhp (430 kW) at 2,585 rpm, 6:1 CRRAF production modelNapier-Railton
LionessE71Inverted layout, for better visibility. At least some were built turbocharged, for racing.
Sea Lion1933: 500 and 600 bhp (370 and 450 kW)Marine version of Lion XI

https://en.wikipedia.org/wiki/Rolls-Royce_Condor_diesel

In 1932 the Air Ministry initiated a conversion of the Condor petrol engine to the compression ignition system. The conversion was developed at the Royal Aircraft Establishment, Farnborough, with the co-operation of Rolls-Royce Ltd. Engine layout, bore, and stroke remained the same as for the petrol version; the compression ratio increased to 12.5:1. The more robust construction required to withstand the increased stresses increased the engine weight to 1,504 lbs (682 kg). At its maximum 2,000 rpm the engine developed 500 hp (373 Kw), giving a power/weight ratio of 0.33 hp/lb.[3]
The engine passed the 50-hour civil type test for compression ignition engines, being only the second British engine to do so. The only previous engine to pass this test was the much larger Beardmore Tornado fitted to the R101 airship. The diesel Condor was experimentally flown in a Hawker Horsley to explore the practical operation of a diesel engine in flight.