Trouble free, most expedient way to 2000 HP engine for 1941

[tomo pauk]

For each of engine-making companies in the world.
2000 HP is with 95-100 oct fuel of the day, while 1800 is good if the 87-92 oct is what can be had. Piston engine only, on metallurgy of the day, and we will set aside the possibility of water-alcohol injection.
Engine should be in service by at least late Summer/early Autumn of 1941, IOW the design needs to commence some time in 1937? Goal is to have a reliable engine, even if that means that somewhat bigger price in size or weight is paid.

Granted, some 18 cyl radials are already in the ballpark...

 

[yulzari]

Easy as. Rolls Royce Peregrine upgrade in a Westland Whirlwind. 2,000bhp. Job done, home for tea and medals.

 

[z42]

I think several marine diesels were capable of well over 2000 hp by that time..

As for aero engines, well..

• RR: Laser focus on the Griffon, reversing the historical focus on the Merlin. Alternatively, persist in fixing the Vulture.
• Napier. Sabre, except with poppet valves.
• Bristol: Forgetting sleeve valves should enable bringing Hercules and Centaurus into service years earlier than historically. Still doubtful whether Centaurus would have been ready in 1941.
• P&W: The historical R-2800 largely basically fulfills the requirement.
• DB: Concentrate on the 603.
• Jumo: The 213. Still I'm pretty doubtful the required power would be achievable in 1941.
• BMW/Wright/Allison: I don't see a realistic path here. Maybe Wright could compress the timeline for the R-3350, but doubtful.

Now this list obviously suffers hugely from being made with the benefit of hindsight. Not that easy to decide in 1937.

I don't think any of the Italian / Japanese / Soviet / etc efforts had any possibility to reach these power levels in 1941.

 

[tomo pauk]

W24 might be viable for: Allison (basically the V-3420 done early), RR (both from Peregrine and Merlin as part donors), Chrysler (made instead of the IV-2200), M-105, L.122 (with Italians still in liquid cooled business), HS12Y-51 (obviously requiring France to be still in the game). Granted, the W24 spin off from the Merlin will be one heavy engine and a bit on the wide side ( just like the V-3420 was), but with benefit of making much more than 2000 HP on 100 oct fuel even in 1941.
Upright engines don't have the problem of fuel+oil dripping down to the hot exhausts like the inverted types did.

Lighter engine should've been achieved with H16 spin offs, but only Merlin and V-1710 can compete here among the engines listed above. Shortcoming is that commonality between the V12s is much reduced. Engines that might be considered as starting points include DB 601 (H16 being less risky than the DB 606, with less power but shorter and with lower weight, so it can also be installed on smaller A/C), Jumo 211 (less risky than the 222), AM-35/38 (now this is one bulky and heavy, if very powerful engine), DB 603 (again bulky, heavy and powerful type, close to the DB 606 in that regard; less risky than X24 and W24 DB types).
The H16 Prince by Fairey was an historical example, even if the power was not as high as I've stipulated as required here.

W18 engines were tried, and even raced, so that is another path to explore.

 

[mack8]

I would say the best bet is to trade size/capacity for power, in other words bigger engines.

Actually the japanese COULD get 1800 HP in 1941, Nakajima was working on a 18 cylinder 140x160 engine in 1937, but if they stick with Ha-5 cylinder size 146x160, and focus on it instead of the useless Ha-20 and the failed Mamoru, they SHOULD get 1800 HP out of this 48 litre engine using the same basic cylinder/supercharger design as the Ha-109.

For germans again same recipe, take BMW-132 or Bramo-323 cylinders, join together for an 18 cylinder, reduce the stroke a bit to about 48-49 litres, so you get an 1800-1900 HP engine on B4 with good reliability. Alternatively, have an 18 cylinder based on the 129/329 cylinder size, which works out about 53-54 litre i think, R-3350 size, good for 2000 HP on B4.

Bristol, absolutely agree about the useless sleeve valve thing, could easily have had a 2000 HP Centaurus with normal valves by 1941.

Vulture, should have taken instead Merlin cylinders, reduce stroke to again about 46-47 litres, reduce rpm to a more sedate 2600-2700 or so to increase reliability, and voila, 2000 HP on 100 octane easy-peasy.

Sabre, well If the Vulture works then no need for it. On the other hand, If it still exists, then again forget about the fancy sleve valves and ridiculously high rpm, size it to at least 45 litres and reduce rpm to 3000 or less.

Jumo, take the Jumo-222 but with the later capacity of 49 litres, reduced rpm to give you 2000 HP on B4

Italians, well for them the only way is to nipponize their engine design somehow. Take the big 53 litre P.XII for instance, should give 1800 HP if nipponized.

Soviets, already had some engine prototypes in the 2000 HP class at this time, such as M-71. Probably if they start a bit earlier/a bit more focus/less hindrance from the purges they SHOULD get at least a decent 1800 HP radial from one of their designers in 1941

Etc. etc.

 

[bf109xxl]

I don't think any of the Italian / Japanese / Soviet / etc efforts had any possibility to reach these power levels in 1941.

Shvetsov's M-71 reached 2000hp in 1940 during the factory test according to Kotelnikov, in February 1941 two M-71 were delivered to Polikarpov to be installed on the I-185. The M-71 engine was ready for serial production in 1942.

 

[bf109xxl]

Soviets, already had some engine prototypes in the 2000 HP class at this time, such as M-71. Probably if they start a bit earlier/a bit more focus/less hindrance from the purges they SHOULD get at least a decent 1800 HP radial from one of their designers in 1941

Etc. etc.

The main problem with the M-71 was the long piston stroke. The M-73 with short stroke was quite successful and was quickly brought to serial production. But in 1942, the M-71 successfully passed state tests with a result not much worse than that of other Soviet engines of the same period. The M-81 (direct ancestor of the M-82) reached 1600hp in 1939, and the M-82 reached 1700hp in 1940. The major problem of early M-8Xs was the fuel system - it is just my humble opinion. Shvetsov used a Holey-type carburetor which was extremely unreliable and provided poor mixture quality. The engine required direct fuel injection - taking into account the quality of the soviet aviation fuel.

 

[z42]

The main problem with the M-71 was the long piston stroke. The M-73 with short stroke was quite successful and was quickly brought to serial production. But in 1942, the M-71 successfully passed state tests with a result not much worse than that of other Soviet engines of the same period. The M-81 (direct ancestor of the M-82) reached 1600hp in 1939, and the M-82 reached 1700hp in 1940. The major problem of early M-8Xs was the fuel system - it is just my humble opinion. Shvetsov used a Holey-type carburetor which was extremely unreliable and provided poor mixture quality. The engine required direct fuel injection - taking into account the quality of the soviet aviation fuel.

It seems the M-7X series eventually resulted in mass production in the guise of the Ash-73, but that was a post-war engine. But yes, maybe better management (and less purges etc). could have resulted in a high power engine earlier.

Shvetsov ASh-82 - Wikipedia

en.m.wikipedia.org

But indeed, Ash-82 came quite close to the required power much earlier.

 

[z42]

I don't think H16 is a particularly interesting configuration. Only a few more cylinders than a V12, bigger frontal area, and weight of two crankshafts.

 

[tomo pauk]

Actually the japanese COULD get 1800 HP in 1941, Nakajima was working on a 18 cylinder 140x160 engine in 1937, but if they stick with Ha-5 cylinder size 146x160, and focus on it instead of the useless Ha-20 and the failed Mamoru, they SHOULD get 1800 HP out of this 48 litre engine using the same basic cylinder/supercharger design as the Ha-109.

For germans again same recipe, take BMW-132 or Bramo-323 cylinders, join together for an 18 cylinder, reduce the stroke a bit to about 48-49 litres, so you get an 1800-1900 HP engine on B4 with good reliability. Alternatively, have an 18 cylinder based on the 129/329 cylinder size, which works out about 53-54 litre i think, R-3350 size, good for 2000 HP on B4.

The 18 cyl radials seem to me as the most realistic option.
Mitsubishi might've came out with the 18 cyl sibling of the Kasei, as they eventually did with the Ha 42 but a few years earlier. Sell off/outsource the Zuisei design to perhaps Hitachi so the company can focus better on bigger engines.

BMW can get there with the 132 as a pattern for bore, stroke and cylinders, so the alternative '139' is indeed 18 cyl engines as it was claimed in English-language books in 20th century.

I don't think H16 is a particularly interesting configuration. Only a few more cylinders than a V12, bigger frontal area, and weight of two crankshafts.

I find it most interesting
Having two (short) crankshaft means these can be light while still being stiff (or, alternatively, can be very stiff and still not overweight), and power impulses from the air-fuel mixture explosions are 'spread' in a less punishing way than it will be the case with X16 or X24.
Nobody expects that an engine much more powerful than an ordinary V12 is without shortcomings, bigger frontal area and weight are certain things here. After all, we're expecting 1800-2000 HP from just a single engine, the 'no free lunch' rule applies as ever.

 

[Shortround6]

Since the R-2800 is pretty much the gold standard in 1941 we need to look at it a bit more closely.
We also have to realize that they only built 10 of the 2000hp engines in 1941. P&W built 2 single stage engines and 6 two stage engines and Ford built 2 single stage engines.
P&W and Ford did build 1723 of the 1850hp versions in 1941 though so a working, in production, being installed in production aircraft is a pretty high bar.

R-2800
46 liters
18 cylinders
2700rpm
2300lbs (depends on model)
100 octane (US) later models rated on 100/130.

Pretty much any V-12 is out of the running and the 16 cylinder engines are out too unless they use very fancy engineering.
You need either
Very large cylinders.
Very high RPM.
A LOT of boost (1941 fuel remember)

The Vulture used
42.5 liters
24 cylinders
2850rpm
2450lbs (plus coolant/radiators)
and was about 200hp low (87 octane? )

DB 603A (assumes you can get it into production 1941)
44.5 liters
12 cylinders
2700rpm
2030lbs
over 250hp low (87 octane fuel)

Wright may have been close with the R-3350, there were two R-3350 engines.

XB-19 used the early ones rated at 2000hp. The later ones used in the B-29s were rated at 2200hp but used different crankcases (about 2 in longer) and different crankshafts and most of the rest engine being different also. I have no idea if the early were any more reliable except that the XB-19 did not set itself on fire and managed to fly from June of 1941 until sometime in 1943 when it was refitted with Allison V-3420 engines, cooling difficulties were noted however.

Just about any existing (in mass production) V-12 will have cylinders too small to use in a 16 cylinder engine to get the required power in 1941.
A 16 cylinder DB 601E won't do it and neither will a 16 cylinder engine using DB 605 cylinders of even 1942 (even assuming it will use 1.42 ata pressure)

Please remember that P&W spent hundreds of hours on test stands sorting out the vibration problems with the R-2800.
Running 2-3 engines in testing can be several years away from actual mass producing a viable engine.
Soviets were rather famous for this, (or not famous, this didn't become known for many decades) and ordered batches of engines of sometimes hundreds to be built while the engines were still being tested and the engines were either never used or installed in aircraft and never/rarely flown.

Fairey had the H-24 Monarch engine

But it had some limitations.
51 liters
24 cylinders
3000rpm
2180lbs dry
Width: 43 in
Height: 52.5 in
2240hp

 

[tomo pauk]

Pretty much any V-12 is out of the running and the 16 cylinder engines are out too unless they use very fancy engineering.
You need either
Very large cylinders.
Very high RPM.
A LOT of boost (1941 fuel remember)

For H16 and required power, obsolete V12s are certainly out, so are the small V12s (these will serve better in a path towards 24 cyl engine of required power).

For a 16 cyl will need about 113 HP/cyl to make 1800 HP, or 125 HP/cyl for 2000 HP. Meaning we need equivalent V12 doing 1350 HP (87 oct) or 1500 HP (100 oct).
DB 601E was good for ~1280 HP at 2.1 km (2500 rpm, 1.3 ata); in very late 1941, it was good for 1450 at 2.1 km (2700 rpm, 1.42 ata). Merlin of 1500 HP - perhaps Mk.XX with a bit greater boost, like +14 psi?
AM-38 - 1600 HP, so the H16 sibling can fly, literary. Will need to switch to blade-and-fork con rods, though.
Jumo 211F can also play here, 1340 HP for take off, 1390 at 1.1-1.2 km.

V-1710-based H16 will need more faith, it was some time before the overboost was agreed upon.

DB 603A (assumes you can get it into production 1941)
44.5 liters
12 cylinders
2700rpm
2030lbs
over 250hp low (87 octane fuel)

DB was promising ~1870 HP at ~1.6 km in April of 1940 for the DB 603, that is more than requested on 87 oct fuel.
Granted, for a DB 603 to work, it will need to have at least two things - major axing of a host of future DB engines (no X, W or V16 engines) so DB has resources better focused on the 603, and more favorable attitude by RLM (better material and moral support between 1938-41).
H16 'version' of the DB 603 might've been very interesting, too. Even short-stroked.

Fairey had the H-24 Monarch engine
But it had some limitations.
51 liters
24 cylinders
3000rpm
2180lbs dry
Width: 43 in
Height: 52.5 in
2240hp

Limitations that come to mind are mostly (bad) timing and inability of Fairey to put this in serious production. Size and weight will certainly prevent it from installation on a fighter that is smaller than Typhoon (no biggie, though).

H24s might've been interesting option for Chrysler (make it instead of the IV-2200), RR (instead of Vulture), Jumo (instead of the 222), Fiat and I-F (along with H16s had they remained in liquid cooled engines' business), HS (with France still in the fight).
Also a poppet-valve option for Napier when they started moving from air-cooled engines.

 

[Shortround6]

We kind of have to figure what a 2000hp engine in 1941 was.
The R-2800 would give you 2000hp for take-off and low altitude (very low) unless you added several hundred more pounds of auxiliary supercharger.
However it would also give 2000hp anytime it was asked for about 5 minutes at a time with no special maintenance procedures or any reduction in engine life.
It would also give 1600hp in low gear for as long as wanted or until the fuel ran out (and at 180-200 US gal a hour that could be pretty quick).

Using high boost settings or WEP settings skews the playing field. Using high boost settings for take-off gets you into the situation the B-29s got into (for different reasons)
A high number of failed engines on take-off or climb to operational height. You may get away with it on fighters, with multi engine aircraft that take a lot longer to reach operational altitude it is a lot risker or costlier.
In 1941 even the British were not using the high boost settings (over 12lbs) on the Merlin's very often even for combat. And some of the Merlins were special low altitude engines with low geared superchargers.

To be fair that was what the R-2800 was. It only gave 2000hp to about 1500ft without ram in low gear unless you fitted the "several hundred more pounds of auxiliary supercharger".
High gear dropped you to about 1600hp and that was good for 13500ft. Now for bombers (B-26B-1) in 1942 that meant a high speed cruise of about 1450hp at 13,000ft at about 180gph per engine.
The R-2800 was being built with the 2 stage mechanical engines to the tune of almost 1100 engines in 1942 which exceeds by about 800 the number of planes that were completed/delivered with the 2 stage mechanical engines in 1942. Engine delivery was not the problem

For most people a 2000hp engine in 1941 means completed aircraft entering service in 1942.

24 cylinder engines means higher cost. We are back the the British not wanting to build the Whirlwind because it used two engines (12 cylinders each) ) but they were perfectly happy to build Typhoons/Tornadoes with one engine (24 cylinders)

 

[tomo pauk]

We kind of have to figure what a 2000hp engine in 1941 was.

Engine that can give 2000 HP in service, high octane fuel is allowed.
As noted above, 1800 HP at 87-92 oct fuel qualifies for this thread.

Using high boost settings or WEP settings skews the playing field.

See above for 1800 vs. 2000 HP.

24 cylinder engines means higher cost. We are back the the British not wanting to build the Whirlwind because it used two engines (12 cylinders each) ) but they were perfectly happy to build Typhoons/Tornadoes with one engine (24 cylinders)

The no free lunch rule applies as ever.
Fighter designed around a 24 cyl will be of lower cost than a fighter designed around two 12 cyl engines, provided the tech used is the same (ie. no sleeve valves, equal supercharging tech etc). British were paying for Beaufighter, powered by two 14 or 12 cyl engines, while Japanese were paying for smaller fighter powered by two 14 cy engines - a fighter powered by 24 cyl engine is a bargain vs. these. Or if it powered by 18 cyl radial.
Similar for the Italians with two 14 cyl engines on the Ro.57.

 

[z42]

I kind of like this Italian racing plane idea with two V12's mounted behind each other, independently driving counter-rotating props.

But for this thread, it's cheating.

 

[Shortround6]

H24s might've been interesting option for Chrysler (make it instead of the IV-2200)

Maybe, unfortunately many engine designers of the 1939-41 era seemed be rather in love with their own cleverness. Skipping right on by the Wright R-2160 and looking at the IV-2200 we hit a number of questionable design choices and we hit a few limitations
from wiki so

IV-2200
36.4 liters
16 cylinders
3400rpm
2430lbs dry (without turbo or coolant radiator) )
100/130 octane

Power output:
2,500 hp (1,864.2 kW) at 3,400 rpm for takeoff
2,500 hp (1,864.2 kW) at 25,000 ft (7,620 m) METO
2,150 hp (1,603.3 kW) at 3,200 rpm normal rating
1,450 hp (1,081.3 kW) at 2,800 rpm cruise

They used fat bore and a short stroke which kept the piston speed down (2,975 per Wilkinson) but helped add to the length.
The 2500hp rating was at 21.0lbs/72.0 in boost (per Wilkinson)
Military and normal ratings are given at 30,000ft (per Wilkinson) which sounds like they were using a late model Turbo ( P-47N?)
yes it was a Hemi, but it only used two valves per cylinder.

Design work started in 1940 so expecting a useable engine in ???????
Basically Chrysler is out due to timing. It takes 3-5 years to go from design to production.

 

[tomo pauk]

I kind of like this Italian racing plane idea with two V12's mounted behind each other, independently driving counter-rotating props.

But for this thread, it's cheating.

Have them make a W24 instead?

 

[Shortround6]

I kind of like this Italian racing plane idea with two V12's mounted behind each other, independently driving counter-rotating props.

But for this thread, it's cheating.

Use it but you have to use the real limitations.
Like regular fuel.
While the engines drove the props separately the engines were connected and rotated at the same speed. One supercharger at the back feed both engine blocks and that lead to a lot of problems, backfire in that duct/manifold tended blow off parts of the cowl.

You could not actually run the plane on one engine/prop if one engine failed so.....................is it one engine or two?

 

[GrauGeist]

The quest for "hyper engines" started in the early 30's, but the technology of the day was a serious limitation.

Continental was on the right track with their IV-1430, which was on a par with Rolls-Royce's PV-12 early on, but then hit a ceiling with it's weight.

 

[Shortround6]

Continental was on the right track with their IV-1430, which was on a par with Rolls-Royce's PV-12 early on, but then hit a ceiling with it's weight.

Hit a few other problems.
Somebody at Wiki has been drinking the Continental kool-aid.

Continental built the first I-1430 engine in 1938 and successfully tested it in 1939.[1] At the time it was an extremely competitive design, offering at least 1,300 hp (970 kW) from a 23-liter displacement; the contemporary Rolls-Royce Merlin offered about 1,000 hp (700 kW) from 27 L displacement, while the contemporary German competitor to the 35-litre displacement Junkers Jumo 211 engine, the Daimler-Benz DB 601 inverted V12, offered slightly more power at 1,100 hp (820 kW), but was much larger, at 33 L displacement

The key here is the 1939 date. The I-1430 was not even assembled in 12 cylinder form until 1938 which was 3-4 years after the other 3 engines. The Merlin had been "offering" 1000hp in 1935 ( flying several prototypes) when the I-1430 only existed in 2 cylinder test rig form and drawings. In 1939 RR was delivering two speed Merlin XX engines delivering (not offering) 1130hp at 5,250ft. The British were testing the Merlin III's using 100 octane fuel and delivering 1310hp at 9000ft. Engine for the Speed Spitfire had been tested at over 1600hp for 10 hours in 1938 (not on av gas). The DB 601 had powered the Me 209

to a world speed record in 1939 making over 1775hp (again not on avgas) and was powering hundreds (over 1000?) German aircraft in 1939.

In 1943 the I-1410 was failing miserably to make rated power if it could be persuaded to run for more than short periods of time.