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

[GrauGeist]

Yeah, not sure about wiki - I prefer Old Machine Press for info on Aero engines:

Search Results for “Continental IV-1430” – Old Machine Press

New Memories of Old Machines

oldmachinepress.com

 

[z42]

Have them make a W24 instead?

The reason for me liking the "two V12's" approach is to

1. Avoid the need to develop a new engine, or for that matter tightly bolt two engines together and then worry about new and exciting vibration problems.
2. Small frontal area.

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?

I meant the general approach, not copying every ill thought out idiosyncracy of the historical inspiration.

 

[tomo pauk]

The reason for me liking the "two V12's" approach is to

1. Avoid the need to develop a new engine, or for that matter tightly bolt two engines together and then worry about new and exciting vibration problems.
2. Small frontal area.

How good is a tandem V12 (V24?) as a practical engine for military aircraft installation?
Such a powerplant relocates the cockpit well back, sorta what happened with Curtiss XP-37 or Bell model 3 (for different reasons, but still - it makes F4U and Spitfire miracles of frontal visibility in comparison), and it also precludes any meaningful fuel tankage in the fuselage.

 

[z42]

The 18 cyl radials seem to me as the most realistic option.

Yes. But with the caveat, as IIRC mentioned by SR6 in another thread, that it seems making a successful 18 cyl radial turned out to be significantly more complex than just slapping two 9 cyl radials together. Lots of manufacturers were successful with 5/7/9 cyl single row radials, quite a few had success with two row 14 cylinder ones too. But 18 cylinder ones that didn't run into lots of problems and were massively delayed were few and far between.

A relatively conservative H24 might have a decent chance of success, too. Or then just a very big V12, say 40+L.

About H16:

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.

I'd say tack on a couple of cylinders at each row, producing a H24, giving your design a lot more legroom, and Bob's your uncle.

 

[z42]

How good is a tandem V12 (V24?) as a practical engine for military aircraft installation?
Such a powerplant relocates the cockpit well back, sorta what happened with Curtiss XP-37 or Bell model 3 (for different reasons, but still - it makes F4U and Spitfire miracles of frontal visibility in comparison), and it also precludes any meaningful fuel tankage in the fuselage.

Indeed, as such maybe more practical as a nacelle installation on a big aircraft.

Or if using inverted V12's, put the cockpit between the engines, with the prop shaft going between the legs of the pilot?

But anyway, I digress, this seems off topic for this thread.

 

[tomo pauk]

Yes. But with the caveat, as IIRC mentioned by SR6 in another thread, that it seems making a successful 18 cyl radial turned out to be significantly more complex than just slapping two 9 cyl radials together. Lots of manufacturers were successful with 5/7/9 cyl single row radials, quite a few had success with two row 14 cylinder ones too. But 18 cylinder ones that didn't run into lots of problems and were massively delayed were few and far between.

My understanding is that P&W was succesful, while Wright would've been well advised to keep the R-3350 at 2000 HP? Soviets were also doing well with M-71, even if it was not produced (due to Soviets being stretched thin, as well as due to a lot of focus on production of 1000-1200 HP M-105s and M-88s?).
Japanese Ha 42 was old tech, drawing a lot from Kasei - not new tech like Homare or Ha 43 - so that is perhaps doable for 1941 if Mitsubishi discontinues one of smaller radials, preferably Zuisei. Nakajima can do the same, while not embarking on Homare and Mamoru.
British can try with 2V head for a Mercury-based 18 cyl type, no sleeve valves. Germans - BMW 132 or Bramo 323 spin-offs rather than BMW 193/801 14-cylinder engines?

Will this work for all the interested parties? Probably/likely it will not without hiccups, so again I'd try and keep things classic (no sleeve valves, keep magnesium out of engines, 2 valves per cyl, no race to make the most compact engine, no rush for very high RPM etc) and make the 18 cyl a reasonably big engine, 3200+ cu in. and 55 in diameter.

Indeed, as such maybe more practical as a nacelle installation on a big aircraft.

Or if using inverted V12's, put the cockpit between the engines, with the prop shaft going between the legs of the pilot?

That is two V12s

But anyway, I digress, this seems off topic for this thread.

Roger.

 

[Shortround6]

Bolkhovitinov S-2M-103 Sparka

The Bolkhovitinov S-2M-103 Sparka was a unique fast-attack aircraft with tandem engines and contra-rotating propellers. The Soviet aircraft first flew in 1940, but technical difficulties and WWII l…

oldmachinepress.com

Should give you all you want to know

 

[Shortround6]

while Wright would've been well advised to keep the R-3350 at 2000 HP?

They might have had more time/money to work in the R-3350 if they hadn't flushed 6.5 million dollars (1940-41 money) and tens of thousands of man hours on the R-2160 project and started frantic catch up with the "new" R-3350.

Soviets were also doing well with M-71

Or were they?
Start with the M-70 using M-25 parts in 1937 at 1400/1500hp.
Shift to the M-71 using M-63 parts by the beginning of 1939. Four prototypes built that year.
5th Prototype built in Jan 1940 introduced two pendulums (balancers) introduced. number built????
factory testing started on this version in 1940, it took until March-April edit>1942< edit end to test it in the I-185 prototype.
It did not pass state (government) tests until Autumn of 1942.

From Wiki
"Based on the glowing report by the NII VVS (Nauchno-Issledovatel'skiy Institut Voyenno-Vozdushnykh Sil—Air Force Scientific Test Institute) in early 1942 preparations began to put the I-185 (M-71) into production. .................. It underwent manufacturer's tests between June and October and was submitted for the State acceptance tests on 18 November. However, flight testing was interrupted by the need to replace the engine between 17 December 1942 and 26 January 1943. The new engine failed the next day and the aircraft crashed on 27 January. Flight tests were ordered to be continued with the original prototypes to validate the range figures, but the first prototype crashed on 5 April, killing the pilot as he attempted a dead-stick landing."

It was also flown in Su-6, Su-8 and La-7 prototypes.
The M-71 used a single speed supercharger and there were at least two attempts to fit turbochargers.
M-72 was a boosted M-71 with two speed supercharger and production was supposed to start in 3rd quarter of 1945.
M-73 was being developed in 1944 and 3 prototypes have been built by the end of 1945.

a lot of gaps/delays and not all of them can be blamed on the war.

 

[mack8]

So how about W18 inlines? Apart from a number of interwar of engines, the italians for instance were looking at the L.180 W18 project by WW2, which seems to use Asso cylinders in 3 banks. Would this configuration be made to work for other german, british etc. inlines? A 3 bank DB-601 derived engine seems to get us to the desired 1800-2000HP.
And iirc the soviets even had some Y inlines, i think 18 cylinders as well, have to look into that.
PS: Found the engine i was thinking of, the M-120

Поршневой авиационный двигатель М-120.

Поршневой авиационный двигатель М-120. :: Поршневой авиационный двигатель М-120. Разработчик: В.Я.Климов Страна: СССР Начало разработки: 1938 г. Постройка: 1940 г. В 1938 году под руководством

xn--80aafy5bs.xn--p1ai

 

[bf109xxl]

From Wiki
"Based on the glowing report by the NII VVS (Nauchno-Issledovatel'skiy Institut Voyenno-Vozdushnykh Sil—Air Force Scientific Test Institute) in early 1942 preparations began to put the I-185 (M-71) into production. .................. It underwent manufacturer's tests between June and October and was submitted for the State acceptance tests on 18 November. However, flight testing was interrupted by the need to replace the engine between 17 December 1942 and 26 January 1943. The new engine failed the next day and the aircraft crashed on 27 January. Flight tests were ordered to be continued with the original prototypes to validate the range figures, but the first prototype crashed on 5 April, killing the pilot as he attempted a dead-stick landing."

The reason for the accident was a manufacturing defect in the carburetor. Three I-185s were successfully tested at the front. There were no complaints about the reliability of the M-71 engines during the tests. Klimov's M-107 had significantly more troubles at that time.
The reasons for the delay in perfecting of the M-71 engine were the lack of engineering staff at the design bureau and the low priority of the M-71 project, while the main forces were concentrated on the M-82.

 

[tomo pauk]

So how about W18 inlines? Apart from a number of interwar of engines, the italians for instance were looking at the L.180 W18 project by WW2, which seems to use Asso cylinders in 3 banks. Would this configuration be made to work for other german, british etc. inlines? A 3 bank DB-601 derived engine seems to get us to the desired 1800-2000HP.
And iirc the soviets even had some Y inlines, i think 18 cylinders as well, have to look into that.
PS: Found the engine i was thinking of, the M-120

Поршневой авиационный двигатель М-120.

Поршневой авиационный двигатель М-120. :: Поршневой авиационный двигатель М-120. Разработчик: В.Я.Климов Страна: СССР Начало разработки: 1938 г. Постройка: 1940 г. В 1938 году под руководством

xn--80aafy5bs.xn--p1ai

French were trying with the HS 18R between the wars, among other things in a Bernard floatplane racer. Seems like engine troubles were often encountered.
I-F were making the W18 engine Asso 750, also inter-war.

 

[Shortround6]

This website has at least 4 articles on 3 bank engines and several on assorted multi banks.

Aircraft Engines: Between the Wars

Click to view all Aircraft Engines: Between the Wars articles starting with the most recent.

oldmachinepress.com

Some of these used some rather strange arrangements of manifolds in order to get around space restrictions, or strange cylinder bank angles to free up space for manifolds.
Hey, in the 1920s and early 30s they didn't know what we know today on what would work and what wouldn't work.

 

[Shortround6]

For the Isotta-Fraschini 750 the intake was, say we say, convoluted.

From the site listed above.
"A manifold attached to the inner side of the left cylinder bank collected the air/fuel mixture that had flowed through passageways in the left cylinder head and delivered the charge to the rear three cylinders of the center bank. The right cylinder bank had the same provisions but delivered the mixture to the front three cylinders of the center bank. "

This required that the cams in the center cylinder bank were set up so that the front of the cams operated different valves than the back half of the cams. The valve arrangement was cross flow but the front 3 cylinders flowed in the opposite direction than the rear 3 cylinders.

Kept the angle between the cylinder banks narrow though

 

[wuzak]

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.

It depends on how the W24 Merlin derivative is built.

If built like the Allison V-3420 with common accessories and supercharger, it could possibly weigh under 3,000lb for a single stage engine.

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 advantage of a W24 or H24 vs an H16 is that more parts can be carried over from the V-12.

The DB 606 was heavier than the V-3420 because it was composed of 2 complete DB 601s, with supercharger and accessories for both, and a common gearbox with clutch mechanism (to isolate one of the engines). This also made the engine wider.

The H16 Prince by Fairey was an historical example, even if the power was not as high as I've stipulated as required here.

H16 Prince doesn't appear to have ever existed, only being a paper exercise on the way to the H24 P.24 Monarch.

Seeking more power, Forsyth investigated a 16-cylinder engine designated P.16 that displaced 2,078 cu in (34.1 L). A V-16 design was initially considered, but the configuration was changed over concerns regarding the engine's length combined with excessive torsional vibrations and stress of the long crankshaft. The P.16 configuration was switched to an H-16 with four banks of four cylinders. However, by switching to an H-24 configuration with four banks of six cylinders, a more powerful engine could be developed that would possess the same frontal area as the H-16. In fact, there is little evidence from primary sources that indicates a P.16 engine or an H-16 configuration were ever seriously considered.

Fairey P.24 Monarch Aircraft Engine

Designed by Richard Forsyth, the P.24 Monarch was Fairey Aviation’s final attempt to enter the aircraft piston engine business. The 24-cylinder Monarch was essentially two engines in a common crank…

oldmachinepress.com

 

[wuzak]

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)

They didn't want to build the Whirlwind because Rolls-Royce and/or the Air Ministry did not want to continue with the Peregrine.

The same fate befell the Tornado at the same time because of the axing of the Vulture.

 

[wuzak]

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.

The Vulture and Sabre would have met the 2,000hp requirement by mid 1941 if they were reliable (and the Vulture hadn't been cancelled). The Sabre may have been a few months later than that.

The Vulture had a 5.00 in (127 mm) bore and a 5.50 in (140 mm) stroke. The engine's total displacement was 2,591 cu in (42.47 L), and it had a takeoff rating of 1,800 hp (1,342 kW) at 3,200 rpm with 6 psi (.41 bar) of boost. At 3,000 rpm with 6 psi (.41 bar) of boost, the Vulture had a maximum rating of 1,845 hp (1,312 kW) at 5,000 ft (1,524 m) and 1,710 hp (1,223 kW) at 15,000 ft (4,572 m). At 2,850 rpm with 6 psi (.41 bar) of boost, the Vulture had an international rating of 1,780 hp (1,327 kW) at 4,000 ft (1,219 m) and 1,660 hp (1,237 kW) at 13,500 ft (4,115 m) and a maximum climb rating of 1,760 hp (1,312 kW) at 5,000 ft (1,524 m) and 1,640 hp (1,223 kW) at 15,000 ft (4,572 m). At 2,600 rpm with 5 psi (.34 bar) of boost, the engine had a maximum cruise rating of 1,540 hp (1,148 kW) in low gear and 1,460 hp (1,089 kW) in high gear. The Vulture was 87.2 in long, 35.8 in wide, and 42.3 in tall. The engine weighed 2,450 lb.

Rolls-Royce Vulture X-24 Aircraft Engine

Developed in the late 1930s, the Rolls-Royce Vulture X-24 was rushed through development and into service. As a result, the Vulture proved unreliable and was cancelled in favor of other aircraft en…

oldmachinepress.com

6psi boost would almost certainly be for 87 octane fuel.

The Vulture V was run with 9psi boost for 1,955hp at take-off, 3,200rpm.

A possible solution to the Vultures issues would be to use a single piece master rod and built up crankshaft.

This was in use by a few radial engines, notably the R-2800, and was used for the late war Rolls-Royce Pennine X-24 prototype.

The Pennine was air cooled, but it ran the 5.4in Merlin bore with a short effective stroke of 5.08in for a displacement of approximately 2,800 cubic inches/46L. Power was 2,750hp @ 3,500rpm, +12psi boost at sea level.

A Vulture developed along those lines could have been handy.


The historic Vulture had several issues during its development, was put into production and service prematurely, but there was potential.

I'm sure a sorted Vulture with +12psi boost, Hooker supercharger and 3,200rpm could have made 2,000hp at altitude by mid 1941.

But there was a war on, and sorting the Vulture was secondary to boosting the performance of what was in hand - the Merlin.

 

[z42]

So how about W18 inlines?

W engines in general seem to have a bit of an awkward shape when viewed from the front. Great if you for some reason want to have a sort-of triangular cross section of the fuselage. And as mention, routing of exhaust for the middle row seems a bit problematic, you obviously don't want to blow the exhaust straight into the windshield.

From a frontal area perspective, a X or H layout looks better, fits better into a "normal" fuselage cross section, and you get another row of cylinders producing power.

And presumably with 3 cylinders per crank throw you can't have fork-and-blade conrods (or side-by-side, not that anyone used those for WWII aero engines, but still). Or I guess it could in principle be possible to have some kind of blade, fork, and "big fork" layout. Though in practice I'm sure the master+slave approach was what was used.

 

[tomo pauk]

Perhaps an interesting detail on the German H24 engine that never grew from a paper stage is the 48L engine suggested by the DVL. In Calum's book, the table that stipulated details was clipped out from the picture at pg. 96, but it can be seen on his web site here.
Apart from the fancy valve train (that probably should not be attampted), engine is oversquare, ie. bore is bigger than the stroke. Bore x stroke was 140 x 130.
That allows for high RPM under modest piston speed, and also keeps engine from growing too tall (or too wide if it is turned by 90 deg, ie. Rapier vs. Sabre layout). Engine was to be more compact than the 'normal' DB 601; on the table, V means engine with poppet valves, while S means with disc valves.
Power was supposed to be 1920 HP at 3000 rpm, or, with more aggressive settings, 2560 HP.

 

[yulzari]

All of this just reinforces my view that, for 1941, the best chance to have the beast in service was a normal twin installation. Using the latest in existing production engines. A couple of 1,000bhp engines are easy to acquire and already work. Many are in the 1,200bhp class. Making more is probably easier than developing something new on 1941 fuels.

All hail the Rolls Royce Peregrine MkII Westland Whirlwind MkII.

 

[tomo pauk]

All of this just reinforces my view that, for 1941, the best chance to have the beast in service was a normal twin installation. Using the latest in existing production engines. A couple of 1,000bhp engines are easy to acquire and already work. Many are in the 1,200bhp class. Making more is probably easier than developing something new on 1941 fuels.

All hail the Rolls Royce Peregrine MkII Westland Whirlwind MkII.

I don't see any challenge in people making 2-engined fighters, with 1000-1200 HP engines for 1941 - it was done many times.