Sir John Valentine Carden survives.

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An excellent summation of what Perkins can do to make the Lion a mass-production diesel. Good thing tank engines don't have the same weight limitations as aero or race engines so Perkins can afford to bulk out the castings for strength and ease of manufacture (and some convenient increases in compression ratios if desired).
I fully expect Perkins' first move will be to cast each bank of cylinders as a unit rather than as individually, that alone should radically improve production time.

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I can only imagine the noise from that forced-draught air-cooled Tatra crammed into an engine bay would be cyclonic.
An air-cooled tank would need some hefty air filters though, getting those armoured could result in some... amusing bulges.
 
Can we please stick to the threads general direction rather then get off on tangents.

Having said that I am Australian and a fan of the Sentinel. This threads POD and the process moving forward will remove the drivers that made the sentinel happen.
I always look at what causes decision A that creates object B. In This case the tank production in Great Britain is less likely to have such huge problems with tank production.
I can see obsolete tanks no longer combat capable being sent to Australia and Singapore for training and familiarisation. This even if only 100 are sent and they take 5 hrs maintenance for every hour of operational practice would be worthwhile in fact it was observed that crews who train on substandard tanks and learn to keep them running end up being more effective in combat. Ie the tank they run is maintained better as that makes a huge difference.

The reason why i read this thread is the quality of the POD and the butterflies i can see. It is not good to derail a thread.
 
What is your definition of "dispassionate"? I am dispassionate. I have been rebutting the bullshit from the other posters, nothing more. It seems I have upset you. I wonder why? Yes, it was 80 years ago. Yes it was by a small nation at the art's end of the earth. My country.
Hey, I'm a Kiwi (born, if not bred), so I can understand trying to have a bit of pride in your country. And a vehicle like the Sentinel is something to be proub about too, it's just that Australia had so many other industrial commitment that, ultimately, setting up a proper production line of the things wasn't worth it.
 
If air-cooled engines were going to be considered than the De Havilland Gypsy 12 is already in production and would be a drop in requiring very little development.

I'd imagine Perkins are going to lift the Lion nameplate and slide a new engine under it, cast iron cylinder blocks and crankcase are a given, the head will need rework, probably with a precombustion chamber in the head to aid the correct mixing of the air and fuel.

Your going to get a big solid lump of an engine with any gains in power cancelled out by the increase in weight, this might have an impact on the reliability of the Vickers designed running gear.
 

marathag

Banned
I can only imagine the noise from that forced-draught air-cooled Tatra crammed into an engine bay would be cyclonic.
An air-cooled tank would need some hefty air filters though, getting those armoured could result in some... amusing bulges.
Patton Tank model
shows fuel tanks, fan exhaust and filter boxes on the fenders
1607020482684.jpeg

Not too bad
 
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marathag

Banned
If air-cooled engines were going to be considered than the De Havilland Gypsy 12 is already in production and would be a drop in requiring very little development.
It's small at 18 liters vs Lion at 24, a lot longer, and I don't know of a single inverted engine used in ground service, this would probably be a 300hp engine in ground trim

Wiki seems to point that only 95 were made

The Lion at this time had already been used on all three Air, Land and Sea applications, and mass produced in the thousands
 
Looking at likely production figures, the Valiant replaces the Valentine (8,275), Covenanter (1,771), plus you're probably taking production from the Cruiser Mk IV (955), Matilda II (2,987), Crusader (5,300), the entire Cavalier project (500), and maybe some of the Cromwell (4,016) and Churchill (5,640) production. I think it's fair to say you could probably see at least 15,000 Valiants getting produced ITTL. This thing is going to be Britain's equivalent to the M4.
 
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It's small at 18 liters vs Lion at 24, a lot longer, and I don't know of a single inverted engine used in ground service, this would probably be a 300hp engine in ground trim

Wiki seems to point that only 95 were made

The Lion at this time had already been used on all three Air, Land and Sea applications, and mass produced in the thousands.
The petrol Lion has been produced in the thousands, the Perkins Lion diesel is still on the drawing board and the one off Ricardo diesel lion is just that, a one off. So stating an alternative engine isn't ideal due to low production numbers is a bit pointless.

I'd imagine by the time that Perkins have the Lion ready for mass production the only items it will share with the original petrol lion will be the bore, stroke and crank design. I wouldn't think that adding air cooling vs water cooling is a good idea along with all the other changes to be made, if we are going that far then just pick an engine that's been developed for air cooling in the first place to turn into a diesel.

The De Havilland is certainly more of a possibility than the the Tatra T995 prototype you keep throwing into the thread, the Tatra is being made in an occupied country and won't run for a couple of years yet.

The point about the inverted engine is moot as well, if you can make a radial work in a tank then an inverted engine isn't an insurmountable problem.

I personally think that UK tank industry had enough trouble keeping water cooled engines working, trying to make air cooled engines work isn't going to go well I think.
 
7 October 1939. London, England.
7 October 1939. London, England.

The Under Secretary of State for War, Sir James Grigg, was lunching in his club with Peter Bennett, the Director-General of Tanks and Transport (DGTT) in the Ministry of Supply. Grigg had received a strongly worded letter the day before from General Roger Evans, commander of 1st Armoured Division. He shared the letter with Bennett and they talked through what they could do about it.

Evans had drawn Grigg’s attention to the ‘grave deficiencies’ in the organisation and war establishment of the Division. The plan was to have 1st Armoured Division ready to take to the field on 1 May 1940. With the mobilisation of the Division on 1st September the influx of reservists had meant that the Division was fully taken up with reorganisation and basic training. There was little scope for doing any training at Regimental level, never mind Brigade or Divisional level. This was partly because of the lack of vehicles, but partly also because of an outbreak of foot and mouth disease which limited the availability of training grounds.

Grigg wanted to know from Bennett what the Ministry of Supply was doing before he replied to the letter. Bennett had spoken to Leslie Burgin, the Minister, about the need to increase the production of tanks, and that therefore it needed to pushed up to the highest level of national priority. Bennett encouraged Grigg to do the same with his own Secretary of State for War, Leslie Hoare-Belisha. If the Cabinet could be persuaded of this, then it would make a difference to tank production over the next few months.

The war establishment for 1st Armoured Division that Evans expected was 58 A10s as ‘heavy cruisers’; 159 ‘light cruisers’ which would be a mixture of A9s and A13s; 24 CS cruisers, most of which would be A9s, and 108 light tanks. The Light tanks were meant to be the Mark VII (A17) with the 2-pdr gun, but since these were still to see the light of day, all were in fact the machine-gunned armed Mark VI. In addition to these 349 tanks, the Division expected to have seven Armoured Control Vehicles and 93 scout cars, of which they currently had not a one. With the current shortage of cruisers, the Armoured Division were equipped with more than 200 Mark VIs but really needed the cruisers. When the cruisers came along, the Light Tanks would be passed on to Cavalry Regiments being mechanised. Bennett noted that the order for 120 Mark VII had been allocated to North British Locomotives which meant that it could be mid-1940 before any of these tanks began to be available, far too late for the 1 May deadline.

Evans had made the decision that the Heavy Brigade would concentrate on the Vickers tanks: 58 A10s, 84 A9s, as well as the 24 A9CS versions, to ease the maintenance problems since all these tanks had the same engine and suspension. Made up of 2nd, 3rd and 5th Battalions RTR, the Heavy Brigade, with current production numbers, wasn’t expected to fully equipped until January. General Evans remarked that if the 40 A9 and A10s hadn’t been sent to the Mobile Division in Egypt, his Heavy Brigade would be closer to its completion.

The Light Brigade, made up of The Queen’s Bays, 9th Queen’s Royal Lancers and 10th Royal Hussars, would expect to each be equipped with 36 light tanks and 22 light cruisers. As the light tanks weren’t the desired A17 with the two-pounder gun, General Evans suggested that it would be better if they were equipped entirely with gun armed light cruisers. The Light Brigade’s current requirement of 72 cruisers would then rise to 174. Nuffield who was building the A13s, expected delivery of the 65 Mark Is to be completed in October, the Mark II with the thicker armour would start arriving from then on. By the end of January, it was expected that the Light Brigade too would be equipped with all its current requirement of 72 light cruiser tanks. If Evan’s request to have a full Brigade’s worth of A13s, that would take at least until the end of May to be done, providing that no other units received any production A13 Mark IIs.

While a full complement of tanks by the end of January was something to be grateful for, Evans noted that the Support Group was even slower at being formed than the tank regiments. There was no sign of the Royal Horse Artillery Regiment being assigned. He had been told that it might join them in France at some point after 1 May 1940. Likewise, the Light Anti-Aircraft/Anti-tank Regiment existed primarily on paper; of the two Motorised Infantry Battalions, one had been sent to Northern Ireland; and the Royal Engineers Field Squadron was deficient in its technical equipment, especially in regards of bridging equipment. The Royal Signals were 100 men short of their establishment; there was only one of the seven required RASC companies; and the RAOC were far short of what was needed, for example, they only had two of the eighteen breakdown lorries, and these were missing their trailers.

General Evans, however, had noted that ‘it is not the provision of material alone which forms the determining factor in our readiness to take to the field, but the provision of material in time to allow an adequate degree of training to be carried out before we go to war.’ He reminded Grigg that he had less than seven months before 1 May. It wasn’t just that he was deficient of important equipment, but also for the personnel trained to use it, as ‘It is not a matter of a week or two to complete our training on receipt of our equipment; it is a matter of months.’ He went on in his letter to say, ‘If this Division is to be ready to take to the field on 1st May 1940, the greater part of its equipment and armament must be in our hands at the beginning of the year; if it is not, the date of our readiness for war must be correspondingly postponed.’

The idea of a postponement wasn’t acceptable to anyone. If anything, with the situation unfolding in Poland, the need to get the 1st Armoured Division integrated into the BEF was all the more urgent. Thankfully Lord Gort was insisting that he didn’t want any more untrained and ill-equipped units under his command. The current situation of the BEF in France was bad enough without having yet another Division that would be better served getting themselves up to speed at home before being deployed across the Channel. The process of moving the BEF into position was proceeding as planned, but it was the largest scale operation undertaken by the Army since 1919, and therefore there were plenty of problems that Gort didn’t want to add to. John Grigg noted that the chances were that the shortages that Evans had identified in 1st Armoured Division were the result of the cupboard being stripped bare of anything useful by the regular forces making up the BEF.

Evans had also noted in his letter that when the tanks were delivered, they often were lacking their gun, which would be delivered separately and then have to be mounted and properly sighted. There was often a gap between the arrival of the tank from the manufacturer and the main armament being available. The bottleneck of producing enough 2-pdrs for both the increasing number of tanks and anti-tank regiments was proving to be a problem. This was made more complicated with the decision to move from the Vickers .303 co-axial machine gun to the BESA 7.92mm gun. There weren’t enough of the new Czech designed guns for training, never mind being available for tank use something that once again was a production problem. It would mean that later versions of the A13 Mark II would be equipped with a different co-axial machine gun. The A10 Mark IA and A13 Mark IIA, whose turrets would be redesigned to take the air cooled machine guns, would complicate logistics if they had to provide 7.92mm ammunition as well as .303 and 0.5 for the Vickers guns. The larger 15mm BESA which was also being introduced, was proving to be full of production bugs, delaying its availability. Evans did admit that if the Light Tanks were armed with this cannon in the Light Brigade, it would go somewhat towards improving their capability until the A13 cruisers were available.

Grigg noted that even if the production numbers of tanks was going to go up by giving a higher priority, the probability remained that the delivery of guns for the tanks wasn’t going to keep up. That was something that Campbell Clarke at Woolwich would have to deal with. It had been suggested that the Mark VII (A17) might have been armed with the Vickers 2-pdr pompom that was used on the A11. If that was possible, then it would save 120 QF 2-pdrs for the cruiser tanks. If Clarke could be convinced that the Light Tanks would be better off with that gun rather than a dedicated anti-tank gun, then it would help. Neither Grigg nor Bennett were convinced Clarke would agree.

Both men knew that there were so many new types of weapon being acquired that there was always going to be a backlog in fielding the necessary numbers. Bennett had visited the Royal Ordnance Factory in Nottingham where 2-pdrs were being produced, along with both 3.7-inch and Bofors 40mm AA guns. They were also in the running to build the new 5.5-inch medium gun for the Royal Artillery. The workforce in this factory, like all the others, was increasing. Delays in training new employees as well as delays in sourcing machine tools meant that it would take time before increased production was possible.

General Evans letter to Grigg had one last comment. He had recently been at Farnborough and seen the Valiant Mark I*, the cruiser version of the Valiant with the petrol engine and thinner armour, go through its paces. Evans had noted that it fitted the bill for a heavy cruiser much better than the A10. In fact, despite its weight and speed, he could see it being much more useful than all the current cruiser tanks. He had also seen the Valiant Mark I, which despite being named an Infantry Tank, was, to his mind, also a far better tank than the current crop of cruisers. He hoped that both models would be available as soon as possible, and if pressed, he believed the Mark I would probably be the better bet in the long run.

Over a brandy, Bennett and Grigg noted that they had both seen the proposal for Vickers Valiant Mark II whose turret had been designed with the new 6-pdr gun in mind. If they could persuade their respective Ministers to ask that a new production line for the new gun could be opened up as soon as possible, allowing for the early entry into service for that weapon, it would be a wise move. Bennett noted that the Vickers-Armstrong company had made bids for producing the 57mm weapon, as they had produced that bore of gun previously for the Royal Navy. Currently Woolwich hadn’t finalised the design for the gun carriage, and there were problems with the number of lathes available for the preferred L/50 calibre. Vickers were keen on going with a L/43 barrel for the tank gun, for which they had the necessary tooling, leaving the anti-tank gun for the Royal Artillery regiments to follow when the carriage was fully worked out. The two men agreed to bring that proposal before their respective Ministers. Grigg would bring the concerns of General Evans to the Secretary of State for War, but just about every commander in all three services were writing letters bemoaning the lack of preparedness for the conflict in which the nation was now embroiled.
 
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Just a note to say that the letter from Evans is OTL and the direct quotes are as it was written. However things are a bit different in terms of earlier production of the A9 and A10 because the A10 wasn't redesigned with the hull mounted MG, and the lower number of Mark VIs being built by Vickers.
 

marathag

Banned
I'd imagine by the time that Perkins have the Lion ready for mass production the only items it will share with the original petrol lion will be the bore, stroke and crank design. I wouldn't think that adding air cooling vs water cooling is a good idea along with all the other changes to be made, if we are going that far then just pick an engine that's been developed for air cooling in the first place to turn into a diesel.
while you are redoing the Lion for diesel, if it's a two stroke uniflow like the GMC Diesel you use piston porting(easy) with a low pressure blower to the crankcase or sleeve valves(v.hard), with both using the cylinder poppet valves for exhaust, with mechanical fuel injectors replacing the magnetos.

If you keep it a four stroke, no need for a blower, you just have monobloc construction for each bank with wet steel liners.
Two stroke is desirable for the most possible power, but are less efficient.

Or do the whole thing from iron, since engine weight isn't the problem it is in the air.

aircooled is desirable,as it's lighter and no coolant leak worries. But liquid cooled is fine, and the Lion will do better, given the advances in antifreeze from just using the earlier water/alcohol mixes
The De Havilland is certainly more of a possibility than the the Tatra T995 prototype you keep throwing into the thread, the Tatra is being made in an occupied country and won't run for a couple of years yet.

Just an illustration for what it could look like as a fan cooled application, nothing more, and
2nd,proof of concept, it was done as a sideline in an Nazi occupied country, so not impossible for the UK

The point about the inverted engine is moot as well, if you can make a radial work in a tank then an inverted engine isn't an insurmountable problem.
But it's one more problem to completely revise the oil lubrication system that just isn't a problem with the W-12
 
Great update, it brings into sharp focus the mad scramble to bring equipment upto date that the UK was suffering from in the late 30s, skilled workers, draughtsmen and machine tools were all in short supply.
 
If your going to change the Lion from petrol to diesel, handbuilt aluminium individual cylinders to cast iron monoblock cast in banks of four with ports to turn it into a two stroke with a blower, the question is when does it stop being a Lion?

Putting sleeve valves in is no more complicated than putting in any other type of valve in, the sleeve vales run off an eccentric cam driven from a shaft, instead of a shaft with cams pushing down on the valves or if your some kind of caveman a pushrod set up, the difficult part is getting the sleeve right which Bristol had no problems with. To my mind it makes no sense to go with sleeve valves as in in this instance the only benefit would be to slightly irritate you Marathag ;)

See this article for further information of the set up Napier used on the Sabre.


Tatra have a history of air cooled V engines, so a side line in that area isnt unlikely, now if you can find me a UK company with a history of air cooled V8s used in road transport i would be surprised, the closest I can think of is anything developed by Frank Halford for aircraft use in the late 20s and early 30s upto the Napier Dagger in the late 30s.

Perkins will build a good engine, but it will be bloody heavy and it will be conservative for the time if they stay true to form, I speak from experience of helping remove a Perkins 4.236 from a Dodge 50 van once to go in a mates Land rover good engine but so heavy.
 
Great update, it brings into sharp focus the mad scramble to bring equipment upto date that the UK was suffering from in the late 30s, skilled workers, draughtsmen and machine tools were all in short supply.
Yep, though again, Vickers seems to be ahead of the trend. If they can get the okay, well, a 6-pounder (even if it's got fractionally less punch than the towed variant) armed Valiant in late 1940 is sure to give Benny the Moose a real headache if he starts anything in North Africa.

I also wonder if they've moved to three-shift, round-the-clock production, or whether they're still on one-shift rates.
 
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Yep, though again, Vickers seems to be ahead of the trend. If they can get the okay, well, a 6-pounder armed Valiant in late 1940 is sure to give Benny the Moose a real headache.

Yes but as Allen illustrates in his post that it will take months of training after the 6pdr Valiant turns up to use it effectively, and it's not just the troops who use them it's the support services as well.

I'd be surprised if any 6pdr tanks are in use before 1941 due to the need to adapt to the new weapon, similarly I don't think the Valiant will make it to France at all as the formations that get it will still be working up before the evacuation begins.
 

Ramp-Rat

Monthly Donor
As always I have been reading the various posts and comments with interest, particularly those regarding the possible issues regarding the use of armoured cars in the top end of Australia. Being British and never despite visits to Australia, I have never been to this area, in ether the dry or wet, so please forgive me if I am completely wrong in what I am about to say. The problem from what I can understand is that armoured cars, would be completely useless during the wet, given the poor to none existence, of any suitable roads in the area. Though they would be very useful during the day season, far more useful than tanks. As I understand it, during the wet virtually all roads would be impassable for wheeled vehicles, and movement near impossible, other on the few all weather roads.

So the question I want to ask is, would this apply to any Japanese invasion force too. And if so why would they invade during the wet, and would such an invasion be subject to major health problems such as insect born illness, in addition to the logistical problems, and problems with the local wildlife and indigenous peoples. I would think, and I am probably wrong, that the Japanese if they were to invade, would only do so during the dry season. And if they did then armoured cars, would in fact be a better option than tanks. Given the massive distances involved, and the much higher speeds of armoured cars in relation to tanks. A mix of armoured cars and truck borne infantry, along with towed artillery and support elements would I believe be the best option to defend the top end.
RR.
 
If the Pom-Pom replaced the 2-pdr Anti-Tank weapon in the light tanks, how likely is it that they go to the Infantry Divisions becoming 'Light Infantry' Tanks while the heavier Valiants and Matilda II's will be diverted to the Armoured Divisions?

I would think that is going to significantly change armoured car development in the UK as well.
 
seeing as Britian is already building bofors i wonder how easy/difficult would it be to use those instead of pompom?
 
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