And regretted it, from the low reliability from said powerplant.
Best tank engines of WWII
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J.A.W.
Banned
The engine itself wasn't the issue, it was the ancilliaries which let it down - being a 1/2 arsed (sadly typical Brit - being a virtual re-run of the issues suffered by their Christie-design 'cruiser' tanks, such as the Crusader, back in WWII) 'nuts & bolts' awkward to fettle, add-on design.
I attach a page from Liberty Engine by Robert Neal. It claims the Lion suffered from detonation issues even with a compression ratio reduced to 4.3:1. I have seen someone on a forum somewhere* suggest it was the ignition system. (It also says 500hp instead of 450hp, I don't know which is correct.)"Mechanised Force" by Fletcher page 125
In 1937 Lt. General Martel had located a surplus stock of such engines belonging to the RAF: the 12 cylinder Napier Lion type X1A which had its cylinders arranged in three banks of four. Tests by MEE indicated an output of 465 bhp at 2,500 RPM, although it would not run well on service type Grade III petrol (65 Octane gasoline) without modification; in any case it was turned down by the Army as a possible waste of money.
Liberty(400hp)
Displacement: 1,649.3 in³ (27.03 L)
Compression Ratio 5.4:1
Length: 67.375 in (1,711 mm)
Width: 27 in (685.80 mm)
Height: 41.5 in (1,054.10 mm)
Dry weight: 845 lb (383.3 kg)
Lion(450hp)
Displacement: 1,461.6 in³ (23.9 L)
Compression Ratio 5.5:1
Length: 57.5 in (1460 mm)
Width: 42.0 in (1067 mm)
Height: 43.5 in (1105 mm)
Dry weight: 960 lb (435 kg)
To me, cheapest 'fix' is use thicker head gaskets on the Lion to lower compression to 5.1:1 or so, and should still get 400ish HP, which is better than the later detuned Liberty at 350HP
](/forum/images/smilies/eusa_wall.gif "Brick wall ](*,)")
*Edit: apparently this was Marathag in a different forum! Still a useful bit of info IMHO.
Attachments
![412 [Lion] - Copy.JPG](/forum/data/attachments/812/812373-08fcb00c0bce07b6bf17a89da07b2e31.jpg)
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J.A.W.
Banned
That's an ignition issue for sure, anyone driven a vehicle from pre-electronic engine management days, & done exactly the same thing?
Those moronic 'brown-jobs' (soldiery) probably thought the 'advance-retard' control was a reverse gear switch or something.
Napier's could've fixed it, if asked - they'd produced an 800hp naturally-aspirated Lion to win the Schneider Trophy race on 10-to-1 comp' ratio,
& their supercharged Lion was boosted up to ~1500hp - to successfully take on the unlimited Land-speed Record at Bonneville...
Edit: & I wonder if Lord Nuffield, who wanted a lucrative contract to churn out those awful Liberty mills, did a bit of 'kickback',
it wouldn't been the 1st or last time the 'military-industrial complex had done those 'dirty deeds'.
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This is a good free resource if you want to get into a crazy amount of detail Technology of tanks : Ogorkiewicz, Richard M : Free Download, Borrow, and Streaming : Internet Archive.
And this is an interesting summary of fuel economy The Foresight War Revisited: AFVs.
My memories from various sources are that the German Maybachs got impressive power/volume but sometimes caught fire as a result. The Liberty got a bad reputation from its specific installation in the Crusader (air intake placement & chain- instead of shaft-driven fan), which combined with the desert environment exaggerated its inherent issues.
Another interesting option is air cooling. The US Army liked it but couldn't afford to develop their own engines which is why the aircraft radials were initially used.
Diesel vs petrol fuel availability & logistics seem to have trumped engine performance in deciding which to use.
Really unlike with combat aircraft it seems like you could get away with pretty much anything assuming it met a basic level of horsepower and reliability. Tanks are so heavy a bit of extra weight from the engine just didn't make that much difference. (The difference in weight between the GAA V8 and Chrysler multibank on the Sherman was something ridiculous that could not be contemplated on an airplane.)
And this is an interesting summary of fuel economy The Foresight War Revisited: AFVs.
My memories from various sources are that the German Maybachs got impressive power/volume but sometimes caught fire as a result. The Liberty got a bad reputation from its specific installation in the Crusader (air intake placement & chain- instead of shaft-driven fan), which combined with the desert environment exaggerated its inherent issues.
Another interesting option is air cooling. The US Army liked it but couldn't afford to develop their own engines which is why the aircraft radials were initially used.
Diesel vs petrol fuel availability & logistics seem to have trumped engine performance in deciding which to use.
Really unlike with combat aircraft it seems like you could get away with pretty much anything assuming it met a basic level of horsepower and reliability. Tanks are so heavy a bit of extra weight from the engine just didn't make that much difference. (The difference in weight between the GAA V8 and Chrysler multibank on the Sherman was something ridiculous that could not be contemplated on an airplane.)
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Seems like it was a bit harder than that now I dug up matharag's old post: The Universal Tank
The real fix for the Lion was ignition timing, easier done with the Liberty than the Lion, as the Lion used a standard aero magneto rather than battery/points that most versions the Liberty used.
J.A.W.
Banned
Not that hard, Napier installed an automatic servo-distributor to its Sabre aero-engine, to compensate the ignition advance curve as part
of the 'single-lever' coordinated engine management system, (& sporting motorcycles of that era - magneto equipped - had manual +/-).
J.A.W.
Banned
To be fair, the Ford was adapted from their attempt at a better V12 Merlin for aero-use, so it would def' weigh less than a quintupling of
all-iron car mills & its complex - which worked, unlike the crappy Liberty set-up.
Incidentally, the Liberty with its inherent off-beat V-angle, & ropy crankshaft, also used to squeeze out its gaskets & seals - under hard use.
Shortround6
Major General
Part of the problem with the Lion was that it was 42in wide. The early cruiser was about 6 ft wide from inner edge of track to inner edge of track. The Liberty was 27in wide.
Just watched a training video on the Crusader tank. It might have been one of the first ones built, watching the valves and valve springs go up and down without any valve covers sort of gives you the hibee-jibees when thinking about operating in the desert
Just watched a training video on the Crusader tank. It might have been one of the first ones built, watching the valves and valve springs go up and down without any valve covers sort of gives you the hibee-jibees when thinking about operating in the desert
Sure it could have been done, but a bit more than "moronic 'brown-jobs' (soldiery) probably thought the 'advance-retard' control was a reverse gear switch or something."
Presumably if they'd picked the Lion in the trials they would have built a wider tank around it. That would have had the flow-on benefit of allowing a bigger turret ring - another weakness of early British tanksPart of the problem with the Lion was that it was 42in wide. The early cruiser was about 6 ft wide from inner edge of track to inner edge of track. The Liberty was 27in wide.
Just watched a training video on the Crusader tank. It might have been one of the first ones built, watching the valves and valve springs go up and down without any valve covers sort of gives you the hibee-jibees when thinking about operating in the desert
J.A.W.
Banned
Yeah, Christie's designs were fairly spacious though, so its a matter of 'interior design' really. & the Liberty was a narrow V (like an H-D bike).Part of the problem with the Lion was that it was 42in wide. The early cruiser was about 6 ft wide from inner edge of track to inner edge of track. The Liberty was 27in wide.
Just watched a training video on the Crusader tank. It might have been one of the first ones built, watching the valves and valve springs go up and down without any valve covers sort of gives you the hibee-jibees when thinking about operating in the desert
Those British sure had something to learn from Chrysler Engineers on how to make complex/awkward installations work properly.
I recall marvelling at a Sea-Lion unit in a maritime museum exhibit, as a kid, & wondering how the internals were organised.
J.A.W.
Banned
True, that was a bit unkind, but knowing how services personnel treat things they don't understand, or take a dislike to, IMO its not too wrong.
British tank design was hamstrung for most of the war by the requirement for rail transport. This limited the width of tanks basicallyPresumably if they'd picked the Lion in the trials they would have built a wider tank around it. That would have had the flow-on benefit of allowing a bigger turret ring - another weakness of early British tanks
up until the restraint was lifted with the Centurion.
interior of Crusader I looking aft
Part of the problem with the Lion was that it was 42in wide. The early cruiser was about 6 ft wide from inner edge of track to inner edge of track. The Liberty was 27in wide.
Just watched a training video on the Crusader tank. It might have been one of the first ones built, watching the valves and valve springs go up and down without any valve covers sort of gives you the hibee-jibees when thinking about operating in the desert
to see the relative width of Liberty engine vs hull
Brit tanks had to be narrow from the Christie suspension on the sides, and the RR loading gauge restrictions, but didn't have to be that restricted in engine choice
8:18 for old training film, to watch that valve action
J.A.W.
Banned
Yeah, they were gas-guzzling maintenance hogs, but fairly tough in Centurion tanks, one of which survived a nuclear test, & then
was refurbished for duty in 'Nam, (don't know if the ghostly 'glow in dark' scared superstitious 'Charlie - ok that bit was a joke).
Apart from the non-user-friendly gear shift, the other issue was same as the Merlin, namely the poorly designed OHC valve actuation.
The cam-followers/lifters were basically a 'consumable item', as they'd wear out/need replacement - way too fast for a ground vehicle.
J.A.W.
Banned
Probably a pumper-carb would've helped, to squirt in a rich shot, when a hob-nail boot slams the 'pedal to the metal', abruptly.
- Thread starter
- #119
Indeed, and it then went on to power the Centurion, which was arguably the best tank of its generation. I think in the competition for "best WWII tank engine", the main arguments against it was that it was quite late, first seeing service in Normandy in 1944. Had they started the project a few years earlier, they could have had something like the Cromwell and a 550 hp Churchill already seeing service in the North Africa campaign, which would have been substantial improvements. Alas, for various reasons it wasn't to be.
- Thread starter
- #120
Does that article you're referring to describe the mechanism for this? In "normal" circumstances one of the features that makes diesel (relatively) safe is that it's so non-volatile that the fuel vapors in the tank saturate to a point below the lower flammability level (which AFAIU is usually considered to be the same as the lower explosive level as well). To reach above the LFL the fuel would either need to be heated quite considerably, or then somehow the explosive charge exploding inside the tank vaporizes fuel and pressurizes the tank to the point a detonation occurs before the tank otherwise bursts?
As an aside, from the perspective of crew survivability I'm not sure this is much of a point against diesel. If a 76+mm shell explodes inside a petrol tank in the crew compartment, if the blast or shrapnel doesn't kill the crew, the explosion spraying and then igniting the petrol from the fuel tank all inside the crew compartment would presumably incinerate the crew.. In both cases it seems the solution is to, well, not put fuel tanks inside the crew compartment.
