A view on why Britsh tanks were so inferior.

[phylo_roadking]

Well, they'd have to be downtuned for reliability and the ability to actually drive through a gearbox without grenading said gearbox!

[Clive Mortimore]

Just a wholly unrelated ( ?) factlet...Vulcan Foundry, the designer/builder of the Matilda, later both on its own and as part of English Electric after a buy-out...in the late '50s was a major builder of Napier Deltic-powered locomotives for the British railway network!

Funny how some historical trends and development paths run congruently....

Napier were by that time also a English Electric owned company. The Deltic was a wonderful marine engine, but as a rail traction engine it was hopeless. Of the 33 locos fitted with them, the prototype was shagged out by the time the production ones were being built, the ten small locos were all rebuilt after five years of entering service and then withdrawn after ten years of working. The other 22 were so molly coddled compared to the rugged slow revving English Electric engine fitted class 20, 37 and 40s but rarely achieved the same availability despite their popular following among railway enthusiast they were not a success.

Clive
Who is finishing off scratch building all 10 Baby Deltics for his model railway. http://scalerail.phpbbhosts.co.uk/viewtopic.php?f=148&t=1188

[Clive Mortimore]

Back on topic the Meteor engine fitted in the Cromwell, Challenger, Comet, and Centurion was based on the Merlin aero engine suitably re-rated for tank use. The Liberty engine in the Crusader, A13, Cavalier and Centaur was based on a WW1 aero engine. Grant and Sherman with their Continental R975 radial engines could not hide that this had an aero engine ancestry. So the suggestion of the Matilda being fitted with an aero engine was sound engineering.

[phylo_roadking]

So the suggestion of the Matilda being fitted with an aero engine was sound engineering.

Clive, I'm not sure this isn't a bit simplistic; somewhere I've an old CMV article discussing this....and around the tank-building world there were more failures than successes attempting to use aero engines I think it depended on the base engine...and what was done with it...

After all - haven't we spent pages and pages earlier discussing the various Nuffield Liberty marks and how they became more unreliable as more horsepower was tuned/teased from the original? To the point that these - "...Crusader, A13, Cavalier and Centaur..." were the ones with questionable reliability I.E. teasing it out THAT long was hardly "sound engineering"...

The Merlin, however, was a remarkable engine that was greatly DE-tuned for it's Meteor installation

(The same principle existed for many years in the Japanese motorcycle industry in the 1970s and 1980s - 250ccs that were scaled-down 400s were reliable...but 350s and 400s that were enlarged 250s weren't! )

[Clive Mortimore]

OK Not sound engineering but a sound engineering idea

[phylo_roadking]

As noted a few pages back, there may have been an even more tuned (and thus even more brittle!) version of the Liberty offered during the development of the Meteor, but it was (thankfully) not pursued!

[PMN1]

OK, so we have an aero-engine ratedat 750-850hp, what would you de-rate to given the weight of the tank – around 14 tons for the improved A11 or 25-27 tons for the eventual A12.

When the Meteor was looked at, the goal was around 20hp/ton but that was for a Cruiser tank in the early 40’s, what would you want for an Infantry tank designed in the late 30’s?

Once you have de-rated, how much effort would it be to go back to the original rating as tanks got heavier?

[phylo_roadking]

When the Meteor was looked at, the goal was around 20hp/ton but that was for a Cruiser tank in the early 40’s, what would you want for an Infantry tank designed in the late 30’s?

Looking at Fletcher - there wasn't too much issue at the time with the Matilda installation's power output at an initial 174 bhp. That's ~6.6 hp per ton! The Valentine wasn't much better, coming in at around 8.4 hp per ton! Later, the firtst Churchill marks only "rose" to 9 hp per ton!!!

OK, so we have an aero-engine ratedat 750-850hp, what would you de-rate to given the weight of the tank – around 14 tons for the improved A11 or 25-27 tons for the eventual A12.

Not that simple - we would have to know what horsepower limitations there were on the various transmissions/gearboxes available!

Once you have de-rated, how much effort would it be to go back to the original rating as tanks got heavier?

One thing we DON'T know is the reliability record of the Napier Culverin!!! It COULD, for instance, have been an unreliable P.O.S.!

[Attrition]

Napier does tend to beg that question....

[PMN1]

Oh I agree there are other factors, just wondering how much of a derating would be looked at, your comparison of the historic hp/ton makes you wonder why someone thought of the Jumo at all, after all Napier has its own engines some of which are in the Jumo range although not diesels...which could be why they were looked at.

In terms of gearboxes/transmission, the A13 cruisers suggest something in the 300 to 400hp is possible. They had their problems but what i've read suggests that it was largely the engine rather than other parts of the package.

[phylo_roadking]

In terms of gearboxes/transmission, the A13 cruisers suggest something in the 300 to 400hp is possible. They had their problems but what i've read suggests that it was largely the engine rather than other parts of the package.

You missed a word there that might just be important -

we would have to know what horsepower limitations there were on the various transmissions/gearboxes available!

"Available" We'd need some REALLY indepth work at Kew to find out if the nation's various gearcutters and transmission manufacturers had the extra capacity at that point to turn out something more in the "300 to 400hp" range

after all Napier has its own engines some of which are in the Jumo range although not diesels

Be interesting to see the September 1936 specs and whether diesel was mandated...

[Felix C]

Should not transmissions be rated according to torque capacity instead of horsepower?

[phylo_roadking]

Felix - nowadays of course; but then? it's actually quite hard to find performance details and specs on period transmissions - except when they didn't work! THEN there's quite a lot of detail!!!

[JBbelgium]

This thread is getting reallly technical, here. I'm not very familiar with the technical aspects of tanks but I would like to sum up a few thoughts on the British tanks and how they were used.
A British tanks were not very balanced at the start of the war. The infantry got support from slow(er) heavy tanks with strong armour. Firepower was sometimes not very good (Matilda I) sometimes better (2 pounder on Matilda II). The cavalry (1st armoured division) had fast tanks with few armour. Firepower was sometimes not very good (Vickers Mark VIB) sometimes better ( 2 pounder on cruisers). As the war progressed things got better. The Cromwell and Churchill still showed some of this heritage but in a less extreme matter.

B One of the thing that made the Panzer III and IV so good was the crew layout. Having three men in the turret was a huge advantage. The commander could concentrate on leading his crew and he had a decent view of the battlefield due to the cupola on top. Most British tanks had a different layout.

C Combined arms are the key to win battles. German panzer divisions were better balanced than the 1st British armoured division in 1940. The same seems to apply to North Africa. Or at least for part of the campaign. Tanks alone don't win the fight, combined arms does.

D British tanks only had armour piercing ammo for their 2 pounders. Tanks had trouble taking on German and Italian AT guns because of this. (This combined with remark C proved to be troublesome.) It took a long time to fix this issue. Too long.

E Panzer III and IV's had large turrets and coud be upgunned and uparmoured. This could not be done as easily with many British tanks.
(examples: The co-ax MG on the Valentine had to be removed to install the 6 pounder. No loader in the crusader Mark III.)

[phylo_roadking]

JB - there's a few old canards in there...

A British tanks were not very balanced at the start of the war. The infantry got support from slow(er) heavy tanks with strong armour. Firepower was sometimes not very good (Matilda I) sometimes better (2 pounder on Matilda II). The cavalry (1st armoured division) had fast tanks with few armour.

The British would argue that at the start of the war their tank force was more..."balanced"...in that there were specific tanks for specific jobs; even the Wehrmacht did this, with E.G. the shortbarrelled PzIVs for infantry support They didn't rely on jacks-of-all-trades being master of none...although the evolution of the tank thru the war DID argue in favour of this as a trend.

B One of the thing that made the Panzer III and IV so good was the crew layout. Having three men in the turret was a huge advantage. The commander could concentrate on leading his crew

The British had exercised for years with the tank commander also acting as gunner - I.E. he not only commanded but fought the tank Technically - it cut down the command loop internally.

C Combined arms are the key to win battles. German panzer divisions were better balanced than the 1st British armoured division in 1940.

1/ "Combined arms" are the key to winning fast offensive battles Slow defensive actions might be another matter...

2/ I know it's very attractive compare the "combined arms" Panzer division with its "integral" panzer genadiers etc. with a "conventional" 1940-period division - but don't forget it was rare for a formation like the 1st Armoured Division to go into action AS a whole division Instead you see its integral tank regiments in action in support of infantry formations - such as 7 RTR supporting the DLI action at Arras. WE tend to think of Arras as a tank action - but the tank action was only part of an overall "combined force" operation. It would be hard to find many actions in the first few years of the war where British tanks ALONE fought an action with no other support of any sort at all.

In other words - in the British mind - arms were combined at the level required within a larger formation.

E Panzer III and IV's had large turrets and coud be upgunned and uparmoured. This could not be done as easily with many British tanks.
(examples: The co-ax MG on the Valentine had to be removed to install the 6 pounder. No loader in the crusader Mark III.)

Don't forget that it went back in again on the Valentine X!

D British tanks only had armour piercing ammo for their 2 pounders.

Discussed several times in this thread - an old canard that's not correct.

Tanks had trouble taking on German and Italian AT guns because of this.

Really? Did the Matildas???