Best tank engines of WWII (8 Viewers)

[Elan Vital]

MB507 was contemplated in the Daimler-Benz competitor to the Panther. However, the production capacity for this engine was far too limited at the time for the demand, and besides the MAN Panther was selected and it had no provisions for this engine. It was believed that the teething troubles of the HL 230 would be shortly eliminated.

In 1942-43, when it was realized that the synthetic fuel industry could provide considerable quantities of diesel compared to low octane gasoline, the Germans ramped up development activity of diesel engines, leading to the SLA-16 X-16, the KHD T8 M118 2-stroke V8, and the Argus-MAN LD 220 H16 4-stroke, all of them delivering a minimum of 700 hp for use on Panther and Tiger II.

 

[WARSPITER]

Yes it was all round the wrong way in the end. Even by 1942 there wasn't enough time left to fully develop decent diesel engines and the mistake
in the earlier years in thinking that synthetic diesel production would be too low really came back to bite.

 

[Shortround6]

Napier used a 130mm bore instead of 105mm and 184 stroke instead of 160mm for a 4.9l cylinder displacement instead of the Jumo 205s 2.76l per cylinder.
The 18-cylinder Deltic also weighed 8860lbs without gear box. Cut to 1/3rd for a six cylinder version?
Also took Napier 6-7 years to build the first 6 "production" engines.

 

[z42]

Napier used a 130mm bore instead of 105mm and 184 stroke instead of 160mm for a 4.9l cylinder displacement instead of the Jumo 205s 2.76l per cylinder.
The 18-cylinder Deltic also weighed 8860lbs without gear box. Cut to 1/3rd for a six cylinder version?
Also took Napier 6-7 years to build the first 6 "production" engines.

Not saying the Deltic would have been a realistic option for WWII. Just that the concept wasn't entirely without merit.

 

[Engineman]

Hi,

The Jumo 205 type concept of opposed piston 2T Diesel with forced induction (preferably Turbocharged) might have been useful if correctly built for the task of a heavy AFV engine.
Certainly, the horizontal arrangement if laid flat may have fitted well. However, the complete 205 type unit with two cranks could not compete with the only slightly later high performance Diesels, IMO.
Although I do like the mystique that envelops the Deltic engine, it would be interesting to know the true advantages/disadvantages that this engine achieved in its railway and nautical operations. Was it just a fortuitous post-war ( war booty, licence-free) UK development that slipped-in to some UK applications for trains and high-speed launches?

Eng

 

[Engineman]

Napier used a 130mm bore instead of 105mm and 184 stroke instead of 160mm for a 4.9l cylinder displacement instead of the Jumo 205s 2.76l per cylinder.
The 18-cylinder Deltic also weighed 8860lbs without gear box. Cut to 1/3rd for a six cylinder version?
Also took Napier 6-7 years to build the first 6 "production" engines.

You can't just cut-it to 1/3 for a 6-pot.

Eng

 

[GrauGeist]

I posted the MB507 as I was thinking of the larger designs such as the Maus since it was fitted to the Maus and the Karl Gerat. The 507
wasn't going to fit in a Tiger or Panther either as it was over 900mm longer than the 205.

Only three of the Karl-Gerät "Morsers" had the MB507C (diesel): Thor, Odin and Loki.

The other four: Adam, Eva, Ziu and VII were fitted with the MB503A (gasoline).

 

[bf109xxl]

Jumo 205 did pretty well for several decades after the war, in the evolved format of the Napier Deltic. Napier Deltic Opposed-Piston Diesel Engine

An even more direct successor to the Jumo 205, which had been in service for decades, was the Kharkiv-built 5TD(F)/6TD mounted on the T-64.

 

[Admiral Beez]

This thread got me looking at the tanks that France was working on like the AMX 40, including variations of the Char G1 with lower height and three man turrets.

The G1 above looks interesting, but I would ditch the mini turret on top and focus instead on crew optimization, communications and fighting ability. As for an engine, what can we put into this 1939 era beast? There were several variants of the G1, including this turretless one below.

 

[Elan Vital]

This thread got me looking at the tanks that France was working on like the AMX 40, including variations of the Char G1 with lower height and three man turrets.

View attachment 883016 View attachment 883018

The G1 above looks interesting, but I would ditch the mini turret on top and focus instead on crew optimization, communications and fighting ability. As for an engine, what can we put into this 1939 era beast? There were several variants of the G1, including this turretless one below.

View attachment 883020

I have redone and continued the research started by the journalist Stéphane Ferrard who wrote multiple articles on the Char de 20 tonnes and G1 program.

Initially the ARL attempted to use a 3-man 75mm turret on the Char G1s, but the extra weight and the fact that many projects exceeded the limit of 35 tonnes for "easy" rail transport meant that they had to go for a lighter 2-man turret. That said I a suspect that the French overestimated the amount of room needed for 3-man crews, as the turret is quite big and so was the turret ring (1.45m diameter was free for the crew, which is more than the Churchill turret for example).

The MG cupola was present on both the Renault and ARL turret as it was preferred that the MG be operated by the commander-gunner, and it was also fitted for observation and, in the case of the ARL at least, fitted for a hunter-killer system where the rest of the turret would slew in the direction of the cupola, so the commander had a lot of assistance compared to a regular 2-man turret. A simplified version of the ARL turret had a simple fixed cupola with a panoramic periscope on top of the episcopes in the cupola.

Automotively, the G1s were quite different in the end.

The Renault entry used a modified Cletrac controlled differential (conservative) with a new transversely-mounted 350 hp 17.6 L straight-six engine able to run on 65 octane petrol. It was of a more robust construction than the engine in the B1 Bis and didn't run on 72 octane fuel which wouldn't necessarily be available in wartime.

The BDR entry used an electric transmission with 2-speed reduction unit and the Potez 12D flat-12 engine, 350hp for a little over 17L as well, but it was air-cooled so the power losses to cooling were uncertain. The electric transmission, like many other such tanks, crippled the design from a weight-efficiency perspective (37-38 tonnes). It wouldn't have been practical beyond a testbed.

The final Fouga entry used a 4-speed mechanical unit coupled to a 2-speed reduction unit, and some form of clutch/brake steering, but it's not very clear. The engine was a 450 hp Flat-8 of 24L, which I suspect was a cut-down version of the Hispano-Suiza Type 86 railcar engine. A good compromise but the project was released in July 1939 so too late before the cancellation of the G1 project after the outbreak of WW2.

The Lorraine entry used twin Cotal units (essentially Wilson characteristics, but with electromagnetic clutches), coupled to a bulky Panhard V12K4F with an output of 350-400-450hp depending on the document, nothing is definitely confirmed as I have yet to find the provisional description manual. The engine was powerful, but bulky and the installation was even bulkier, which drove the weight up to 36 tonnes. Doable, but not efficient.

The SEAM that you posted at the bottom had a lighter but less proven electric transmission mated to a compact 300hp Hispano-Suiza V12. Was relegated to the role of testbed as it could not be modified for the 75mm turret.

In any case the French went beyond that for tank engines programs by 1939-40. They had compact engines (Talbot V12 and Brandt fuel-injected V12) at 340 hp, a Renault 20L V12 at 420hp, a Talbot 19.9L engine at 450-500hp, and an Aster 2-stroke diesel giving 450 to 500hp. Most to be put in mass production in 1941 or 42. All of them were designed from stratch for tank use and are meant to be sturdy and tolerant of low octane fuel as a result.

Though other countries went for even more powerful engines from 1941 onwards, this was a pretty sound lineup which could have served as the basis for bigger and more powerful types.

 

[Admiral Beez]

The SEAM that you posted at the bottom had a lighter but less proven electric transmission mated to a compact 300hp Hispano-Suiza V12. Was relegated to the role of testbed as it could not be modified for the 75mm turret.

Was this related at all to the aero engine?

 

[vandee]

I like the Type 52 myself.

 

[SaparotRob]

I like the Type 52 myself.
View attachment 883174

SRT?

 

[Elan Vital]

Was this related at all to the aero engine?

Completely unrelated, it was related to the Type 68/81 family.

The Type 68 was a 100mm bore x 100mm stroke V12 (9.425 L displacement) delivering 200 hp at 2800 rpm for a compression ratio of 6:1.
The Type 68 Bis was the same engine with 120mm stroke to obtain 11.310L displacement and 240 hp at 2400 rpm and 250 hp at 2800 rpm for the same CR.
Both used "truck"-type fuel with 15% ethanol addition.

The Type 81 appears to have been a modified 68 Bis (same bore and stroke), with output reduced to 228 hp at 2800 rpm and a CR of 5.

The engine designed for the SEAM G1P was an extrapolation with 110mm bore and 130mm stroke with a minimum expected output of 280 hp.

When it was decided that the Type 68 Bis in the ARL V1 75mm SPG would be replaced with a more powerful engine to ensure high durability, the Hispano-Suiza company estimated that they could make such an engine with an increase in length of 60-100mm, width of 20-30mm and weight of 100kg compared to the Type 68 Bis, and that this would deliver 340 hp max at 2800 rpm and 300 hp continuous at 2400 rpm. However, Hispano-Suiza was too busy to entertain development of this engine, so the ARL drew up a specification which got the Talbot and Brandt companies involved instead.

The Type 68 is described here from page 71 to page 86: Cours de technologie des moteurs d'autorails : instruction des apprentis / P. O. -Midi | Gallica

 

[Elvis]

Napier used a 130mm bore instead of 105mm and 184 stroke instead of 160mm for a 4.9l cylinder displacement instead of the Jumo 205s 2.76l per cylinder.
The 18-cylinder Deltic also weighed 8860lbs without gear box. Cut to 1/3rd for a six cylinder version?
Also took Napier 6-7 years to build the first 6 "production" engines.

For comparison's sake, a single cylinder from an R-1820 displaces 3.32L.

 

[swampyankee]

Opposed piston diesels have advantages over other two stroke diesels, like uniflow scavenging without complex valve gear and fewer heat loss paths. Fairbanks-Morse, Doxford, and Sulzer all produced OP engines.

One could argue that Fairbanks-Morse, with their very successful submarine and marine engines were more inspiring than Junkers, with its moderately successful aero engines.

 

[ThomasP]

Info on the RD-1820 diesel as developed in the early-war.

 

[Shortround6]

OK, you got a diesel engine.
The R-975 gas engine used in the M-4A2 was rated at 400hp at 2400rpm and 940ft/lbs of torque at 1700rpm. Torque at engine shaft and not after the reduction/step-up gear.
The parent aircraft engines were 45in dia and 55in dia respectively and the smaller engine was 675lbs vs the 1100lbs of the R-1820 (Guess but I did take off close to 200lbs to allow for the aircraft propeller reduction gear and the 2 speed super charger drive. adjust as needed.)

 

[marathag]

Food for thought

Radials don't have to increase the height of the hull.

Model D-9 was rated 300 hp at 1200 rpm
The bore was 150 mm 5.91 in the stroke 210 mm 8.27 in and the total displacement 1945.62 cu in
The weight was reported to be 990 lbs

Many Salmson Radials were water cooled, including this one

 

[Elvis]

Food for thought

Radials don't have to increase the height of the hull.
View attachment 884244
Model D-9 was rated 300 hp at 1200 rpm
The bore was 150 mm 5.91 in the stroke 210 mm 8.27 in and the total displacement 1945.62 cu in
The weight was reported to be 990 lbs

Many Salmson Radials were water cooled, including this one

At 990 lbs. couldn't you do an R-1820 and realize a 700-900 hp powerplant to move your tank for roughly the same engine weight?