Germans buy Japanese radial engines?

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Germans buy Japanese radial engines?

#1

Post by stg 44 » 26 Aug 2012, 17:18

I recently discovered an online 'what if' scenario titled "France Fights On" that has a number of differences with the historical war, one of which being the Germans discover the Japanese developments in radial engine development an appropriate them for their own radial aircraft engines. The scenario is thus:
Enter the Japanese – Testing the Japanese engines 

BMW were a little sceptical when the Air Arsenal-led multi-manufacturer team arrived in late 1940, bringing with them a number of representative and prototype engines. While Daimler-Benz quickly peeled off with the inline team, BMW worked with the radial team. They were startled at the lack of finish on the Japanese engines. What they observed was though there were far more fins/surface area than a comparable American, French, British or German engine, the fins were far cruder. Many ran into each other and showed the fact that they were from a casting process with very little cleanup beyond manual filing.

What really surprised BMW’s engineers and engine design staff was their simplicity. They compared a French Ghome-Rhone 14M engine with the Nakajima Sakae engine, a developed version based on that engine. The difference is that Nakajima took that engine, retooled it and made it so that instead of running at 700 hp it ran at 940 hp and required half the time to build. They then expanded the engine into the Sakae 21 series that had 1040 hp. Meanwhile Mitsubishi showed BMW an engine, Kinsei 43, which although not based on the GR-14, was similar in size and produced 1740 hp using 10 kg less weight and took less man-hours to manufacture than the Nakajima. 
At this point, many technical lightbulbs began to light up in the heads of BMW’s design staff. 

As for the Japanese, they looked at BMW-801 and asked many questions, most of which started with ‘Why on Earth?’ The engine, though producing about 1500 hp, was a gas hog (even though it was already used in designs like the Fw-200) by Japanese standards as among other things BMW used a very rich mix to assist in cylinder cooling. While a standard matter for aero engines, the Japanese demand for range had led them away from this particular path. Only the planned C and D versions of the engine promised to be somewhat fuel efficient, but only at low altitude. 
The first point the Japanese made was that with BMW did not appear to have embedded their operational philosophy into their design philosophy. This brought about embarrassed silence and meek questions about that that comment meant. The Japanese responded that they had adopted what the operators said they wanted, codified it, and applied it to their design philosophy. What the operators wanted was simple, powerful, easy to maintain, low fuel consumption, rugged engines which worked in the field. The companies took this and applied it, also applying cost reduction as part of the design process. Once they understood that BMW did not do this, they noted that this explained the expensive and unnecessary over-engineering observed on the BMW-801, as well as the poor selection and layout of its auxiliaries. 

The Japanese engines were then put onto the test stands in Germany and started up. The first one was a standard Mitsubishi MK4R-A 'Kasei 23E15' bomber engine which the Japanese team assured BMW was supposed to produce 1530 HP, although they also had a prototype R engine rated at 1750HP. After some issues with running incorrectly it was producing almost 1900 hp. The initial problems with running rough the Germans had seen earlier when they had to come up with tuning settings for their engines when going from 87 Octane to 100 octane. After discussions with the Mitsubishi representatives the mutually appalled Japanese and Germans realised that they were not using remotely comparable fuels. The Germans were astounded to be told the engine was tuned to standard Japanese bomber fuel – 72 octane. The Japanese were astounded to find out that the Germans used 100 octane. The Germans then realised the implications: what they had on the stand was an engine which produced 1530 HP on 72 octane fuel when their best radials produced 1539 HP on 100 octane. 

Next they threw on the Nakajima NK9H 'Homare 21' engine which was supposed to produce 1990 HP. Instead it produced power over 2200 hp. The German engineers after seeing that would not even let them try to run the Mitsubishi MK9A 'Ha-211 Ru' engine which is supposed to run at 2200 hp. The German test stands were only rated to 2400 hp and they needed to be strengthened, which took a week. RLM was told immediately and a large RLM technical team quickly arrived. 

By this time everything was on the table. The Japanese knew that the Germans could assist them in improving the octane ratings of their fuel, while both BMW and RLM knew that the long-established linkages between German and Japanese aviation industries had borne extremely valuable fruit. Both knew that they had things to exchange at the technical level. Quietly and behind the scenes, the BMW technical staffs began to work with their Japanese counterparts arranging technology swaps. 

RLM now knew that the Japanese were using octane fuel in the 72-86 octane band and no better, and that they had mature, technologically advanced radial engines that could make the Fw-190 even faster and revolutionise the German fighter force. What to do? They discussed the options, which were to study the engines and adapt their ideas to new construction, license the engines and build them in Germany, using the secret of lead additive as a bargaining chip to buy the licenses? As technicians, the only thing they all rejected was ignoring it and continuing on as before. 

As this point, Ambassador Onishi arrived with his close friend Heinrich Himmler – which made the policy issue political and at Hitler’s level. Frantic RLM staff immediately advised Göring, who arrived post-haste. He had quickly sent a brief to Hitler himself so as to head off or at least balance Himmler. 

Onishi, well versed in Byzantine Nazi internal machinations, made a modest proposal to both. He suggested that, as BMW was receiving much equipment removed from wrecked French factories, that they and Japanese industry, through the Japanese Government Military Arsenal system set up a joint venture company to build a ‘new BMW engine’ to fill the workaday 900-1200hp range with a cheap, simple, easily maintained engine designed to use the relatively abundant lower quality fuels. This was immediately agreed to as it was an obvious commercial goldmine. He then suggested that, as both Japan and Germany had mutually supporting interests under the Tripartite Axis, that they agree broadly to a mutual, no-cost exchange under the GJTCA of synthetic fuel assistance for radial engine assistance. His trump card was asking the senior BMW engineers what their 801 would produce if BMW incorporated useful technological tweaks from the Japanese design philosophy. When he replied that it would produce about 2000 to 2200HP using less fuel, be easier to maintain and production costs would drop by, he guessed, a tenth, it was all over bar the detailed negotiations. 

This solved a serious problem developing within the German aircraft engine industry. They understood that what they had would peak in capability by early 1942, and that the best which could be expected from a German radial engine that could fit an aircraft like the Fw-190 was about 1730 hp from the BMW 801D-2. Beyond that point the German industry just could not produce a meaningful engine in a radial. Only Liquid cooled in-line engines had shown promise going to higher hp ratings in that engine size range. 

Among those who understood this was Kurt Tank, who was already thinking about how to put an in-line engine on the Fw-190 and create the D longnose. What these tests showed in stark terms was that in Japan, the complete opposite had happened. They already had radials that were in the 2200 hp range and were working on prototypes in hp ranges far higher than this. As a result of the Military Missions, BMW, DB and Jumo obtained access to engines and the Japanese who designed them to study and the results shocked them. Tank realised that this would turn the Luftwaffe on its head. 

This changed everything for the Germans, and it changed nothing. They certainly realised that they had missed an entire development path but there just was not a lot most companies could do about it – except BMW. Not only had BMW been down this path with the Japanese before (their close relationship with Kawasaki from 1928 had been the direct cause of improvements to the BMV VI V-12 (450hp-550hp) which had resulted in the 800hp BMW VII V-12), they were the only ones with a modern, high quality radial engine core. As the Japanese said, when you stripped the BMW-801 back to its core it was a very good engine indeed, and easily able to accept what the Japanese had developed in terms of cylinder super-cooling, layout and fuel management. In return, BMW was able to fix developmental problems with advanced Japanese engines like MK9 by designing a better fuel injection system for it (which they could do in their sleep), and correct the faults with the licence-built Japanese DB-601, the Ha-40. 
The testing of Japanese engines in 1941 under the GJTCA (and after the revelations of the Balbo Mission) led to a ferment at engineer and technical levels within BMW. As was normal within the German aviation industry, BMW already had many years of very close association with Japanese companies. 

BMW-800.
This was developed during 1941 under Air Arsenal auspices by Kawasaki and Nakajima as a commercial venture with BMW. It married French machinery stripped from their damaged radial engine producing facilities and the basic GR-14 design to the technical advances of the Japanese Sakae (itself based on the GR-14 root). This engine had the advantages of being cheap to produce, reliable and as close to no risk as it was possible for an aero engine to be. It used the cheap and simple ‘cylinder super-cooling’ technology the Japanese had developed in casting fins into their cylinders. It was kept low-cost and minimised demands on skilled manpower. BMW adopted the cheap Japanese approach of casting innumerable fins in, and finishing by hand-filing using unskilled labour. This approach was justified as being acceptable for a ‘war emergency’ utility engine. 
This was its own engine and was not a licence built Nakajima Sakae. It was firmly based on the GR-14 design as adapted to BMW building practises and attracted significant attention and even some input from Hungarian and Italian engine designers. The basic comparison unit was the NK1F Sakae21, this itself being developed from the GR-14 root. The BMW-800 produced 1110hp on take-off using the low octane fuels it was designed for. However, the engine could also be retuned to use better fuels, obtaining a useful 1270hp when using 100 octane fuel. 
It was aimed at the Luftwaffe’s utility market and was used on trainers, transport aircraft, and specialist machines like the Hs-129, to which it gave a sparkling performance. It turned the Messerschmitt Gigant motorised glider into a transport aircraft. 

The BMW-800 was produced in large numbers from early 1942. The first proof of concept versions were assembled from captured French components and hand-made parts from the BMW prototyping shops, but design was rapid and without the usual long debugging program as the concept was already mature. While this approach meant that performance was slightly below that of Sakae 21, BMW was not concerned with this. The engine’s development costs were very low and it was what the Luftwaffe needed in this engine range. The engine was unique in being developed to a timeline set by construction of new BMW annexes and bringing into service of captured French equipment. 

BMW-801D
The 801C was replaced in production with the BMW 801 D-2 series engines in early 1942, which ran on C2/C3 100 octane fuel instead of the A/B/C's B4 87 octane. BMW was tooling up for this production when the Japanese bombshell burst. They continued with 801D in order to buy time to properly test and absorb the new technical tweaks being learned, but immediately began development of the 801E, using the 100 octane experience of the 801D and the excellent basic 801 engine core. 

BMW-801E
It used the excellent engine core of the 801 series engine to best advantage. This engine fully incorporated the technical lessons learned from examining Japanese Kasei series engines as well as the formidable eighteen cylinder Nakajima NK9K Homare 22 (2000hp on 76 Octane fuel) and Mitsubishi MK9A (2200hp on 76 octane fuel). These technical tweaks included cylinder super-cooling through use of cast-in finning (although the Germans could not resist an expensive final finishing stage which made it look much less crude although it actually did nothing to improve cylinder cooling), and above all else incorporation of  the engine philosophy the Japanese had developed. 
The result was an engine that was simpler to build, easy to maintain, cheaper to manufacture, and which used less fuel than the earlier 801 versions. The BMW-801E produced 2060hp, a figure which astounded RLM and simply thrilled the Luftwaffe. Better, it did this without the planned system known as MW50, which injected a 50-50 water-methanol mixture into the supercharger output to cool it and reduce backpressure. This was still developed but did not appear until later in the war. When it did, it boosted low and medium-altitude performance improved considerably, with takeoff power increasing by another 170hp. The BMW 801G and H models were E engines modified for use in bomber roles with lower gear ratios for driving larger propellers, clockwise and counter-clockwise respectively. 

As a result of developing the 2000hp class BMW-801E, the Fw-190A-4 entered service in the second half of 1942. Comparison to the Fw-190A-2 is instructive. The A-2 had a maximum speed of 322mph at 3,280’ and 389mph at 18,045’. The A-4 had the startling performance of 357mph at sea level, 415mph at 10,830’, and 440mph at 21,650’. The A-2 was a truly formidable opponent to contemporary RAF Spitfires but the A-4 outclassed literally everything in European skies. Fortunately for the Allies, it was dedicated at least initially to the eastern Front. There, despite its initial small numbers, it caused a slaughter in the ranks of the Red Air Force during the autumn of 1942 unprecedented since the ‘Fokker Scourge’. In one celebrated incident in the third month of the war there, six of these aircraft attacked a full regiment of 21 Yak fighters, and destroyed them all in four minutes. 
One unexpected result of this was the creation of a Fw-190 fighter monoculture in Germany. It ensured the immediate obsolescence of the entire Messerschmitt single engine fighter line. Me-109 continued in production, but the Luftwaffe made it plain from early 1942 that the aircraft would leave production and that the company’s factories would replace them with Fw-190 in the production halls. In the end, the Me-109 did not leave production until late 1943, simply because the powerful new BMW-801E series could not be produced in sufficient volume to justify this. The Me-109 series was also exported to Italy, Hungary and Rumania. 

BMW-802
This was the license-built version of the Nakajima NK9 Homare 22, a mature 18 cylinder design which reliably produced 2000hp. BMW purchased licences for this engine as its own 18-cylinder program was in trouble, and this engine was mature. RLM insisted on this for insurance purpose, and also because they wanted this to offer a development path to 2500hp as a bomber engine. This also made sense as Homare came from the Sakae root, and this increased BMW’s confidence and depth in this engine line. 

BMW-803
This was the license-built version of the Mitsubishi MK9A, a 18 cylinder fighter engine design which produced 2200hp in its prototype version. It came from the Kinsei root, and this led to considerable interaction with the Italians, who were producing a variant of this engine. BMW purchased licences for this engine as its own 18-cylinder program was in trouble, and this engine offered more than the Homare 22. RLM insisted on this as they wanted this to offer a development path for fighters in the 2500hp-3000hp range as a fighter engine. 
Supercharger development
With the engine now being used in higher-altitude fighter roles, a number of attempts were made to address the limited performance of the original supercharger. The BMW 801F was a modification of the E using supercharger gear ratios tuned to higher altitudes. Although takeoff power was unaffected, cruise power increased over 100 hp and "high power" modes for climb and combat were likewise improved by up to 150 hp. The F model was also used as the basis for the BMW 801R, which included a much more complex and powerful two-stage four-speed supercharger. Continued improvements to the basic high-altitude E model led to the BMW 801G, which dramatically improved performance across the board, with takeoff power increasing to 2,400 hp (1,790 kW). It was planned to use the F on all late-model Fw-190's, but the war ended before production started. 

Turbocharger development
A number of attempts were made to use turbochargers on the BMW 801 series as well. The first used a modified BMW 801E to create the BMW 801J, delivering 2145hp, at takeoff and 1600 hp at 40,000 ft (12,200 m), an altitude where the E was struggling to produce 730 hp. The BMW 801F was likewise modified to create the BMW 801Q, delivering 1,875 hp at 40,000 ft (12,200 m), power ratings no existing allied engine could touch. However none of these engines ever entered production due to high costs, and the various high-altitude designs based on them were forced to turn to other engines entirely, typically the Junkers Jumo 213. 


It should be noted too that the Japanese radial engines weighed only 50-75% of the BMW 801.
Is this a viable scenario? And what would happen if the Germans adopted Japanese engine ideas pre-war?

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Re: Germans buy Japanese radial engines?

#2

Post by stg 44 » 26 Aug 2012, 17:27

A quick comparison of contemporary engines:

http://en.wikipedia.org/wiki/Nakajima_Homare
General characteristics
Type: 18-cylinder air-cooled twin-row radial engine
Bore: 130 mm (5.12 in)
Stroke: 150 mm (5.91 in)
Displacement: 32 L (1,940 in³)
Length: 1,778 mm (70 in)
Diameter: 1,182 mm (46.5 in)
Dry weight: 830 kg (1,830 lb)

Components
Valvetrain: push rod operated overhead-valve system with 2 valves per cylinder
Supercharger: Two-speed single stage centrifugal
Fuel system: Water-methanol injection
Cooling system: Air-cooled
Performance
Power output: 1,485 kW (1,990 hp) at altitude
Specific power: 41.5 kW/L (0.91 hp/in³)
Compression ratio: 7.0
Power-to-weight ratio: 1.79 kW/kg (1.09 hp/lb)

http://en.wikipedia.org/wiki/BMW_801#Sp ... W_801_C.29
General characteristics
Type: 14-cylinder supercharged two-row air-cooled radial engine
Bore: 156 mm (6.15 in)
Stroke: 156 mm (6.15 in)
Displacement: 41.8 litres (2,560 in³)
Length: 2,006 mm (79 in)
Diameter: 1,290 mm (51 in)
Dry weight: 1,012 kg (2,226 lb)

Components
Valvetrain: One intake and one sodium-cooled exhaust valve per cylinder
Supercharger: Gear-driven single-stage two-speed
Fuel system: Fuel injection
Cooling system: Air-cooled
Performance
Power output: 1,560 PS (1,539 hp, 1,147 kW) at 2,700 rpm for takeoff at sea level
Specific power: 27.44 kW/L (0.60 hp/in³)
Compression ratio: 6.5:1
Specific fuel consumption: 0.308 kg/(kW·h) (0.506 lb/(hp·h))
Power-to-weight ratio: 1.13 kW/kg (0.69 hp/lb)


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Re: Germans buy Japanese radial engines?

#3

Post by Tim Smith » 26 Aug 2012, 21:23

The German and Japanese problem was not with their radial engines. It was with the turbosuperchargers needed for those radial engines to operate effectively at altitudes above 20,000 feet.

Germany and Japan were two years behind the USA in turbosupercharger design. Plus they lacked the high-quality alloys needed to manufacture them in quantity (e.g. tungsten alloy).

Look at the specs for all the Japanese fighters in WW2. Their maximum speed, for all of them, is obtained at under 21,000 feet (6,400m). Compare that with the P-47 - top speed is obtained at 30,000 feet, thanks to the turbosupercharger.

That's why the P-47 was great at high altitude and the Fw 190A, Ki-84, Ki-100, A6M5, N1K2 and JM-2 weren't.

The best place for the radial-engined Fw 190A was on the Eastern Front, where best performance at over 20,000 feet wasn't necessary as the Soviets rarely flew higher than that, since their air force was orientated to tactical ground support. (Which is why the Soviets were happy with the P-39 without a turbosupercharger, and the Western Allies weren't.)

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Re: Germans buy Japanese radial engines?

#4

Post by stg 44 » 26 Aug 2012, 22:31

http://en.wikipedia.org/wiki/Centrifuga ... percharger
centrifugal superchargers evolved during World War II with their use in aircraft, where they were frequently paired with their exhaust driven counterpart, the turbosupercharger[2]. This term refers to the fact that turbochargers are a specific type of centrifugal supercharger, one that is driven by a turbine[3].
http://en.wikipedia.org/wiki/Pratt_%26_Whitney_R-2800
Variable-speed (in F8F-2, unified with throttle via AEC automatic engine control), single-stage single-speed centrifugal type supercharger
http://en.wikipedia.org/wiki/Nakajima_Homare
Supercharger: Two-speed single stage centrifugal
It appears that both the Pratt-Whitney, which was used in the P47 and the Homare both used the centrifugal supercharger, which, if I understand the first quote, functioned as a turbosupercharger. Was the Japanese model less efficient than the US one or for some reason didn't function as a turbocharger, or was there a turbo supercharger attached that is not mentioned in the Wiki-article?

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Re: Germans buy Japanese radial engines?

#5

Post by phylo_roadking » 26 Aug 2012, 23:15

It appears that both the Pratt-Whitney, which was used in the P47 and the Homare both used the centrifugal supercharger, which, if I understand the first quote, functioned as a turbosupercharger. Was the Japanese model less efficient than the US one or for some reason didn't function as a turbocharger, or was there a turbo supercharger attached that is not mentioned in the Wiki-article?
I don't know enough about Japanese aero engines to comment specifically - but it might be worth looking at the aspect of direct-geared vs. chain-driven superchargers/turbosuperchargers ;) IIRC (tho' its been a few years now since I looked at the issues) the chain-driven types took more power away from the total output by soaking up the power needed to drive the installation...but integral geared units like the GE turbosupercharger didn't take quite so much off the total. The driven speed of the Axis superchargers/turbosuperchargers may also have had to be geared down to reduced rpm in the absence of various alloying metals for components. Higher octane rated fuels available to the U.S. may also have permitted a higher specific power output from the turbocharger/engine installation...they certainly had much higher "rich mixture performance numbers" - how well the fuel flowed in turbosupercharger/engine installations with automatic mixture control at altitude!

I posted this the other day on another thread here...
Prior to 1942 there was actually no way to analyse this in the US - which is why the British had to issue their specific blending instructions...."Just follow the insturctions properly guys, and it'll be the same in every batch!" But the CFR Supercharge rich mixture 3-C benchtest motor was introduced in late 1942, and the Rich Mixture Performance Number was THEN set at 125, then raised to 130...so the "new" fuel grade of "Grade 100/130" to US military specification An-F-28 introduced later in the war, for example, was actually good old 100 octane renamed to include the 130 rich mixture number!
It's a different performance parameter to the octane rating of aviation spirit...but definitely influences how turbosupercharged engines breathed at altitude! Interesting how Axis turbosupercharged aircraft performance dropped off at altitude....I'd guess a lower "rich mixture performance number" in their fuels than in American-blended aviation spirit?

Just a thought!
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Re: Germans buy Japanese radial engines?

#6

Post by stg 44 » 30 Aug 2012, 22:47

What about this engine:
http://en.wikipedia.org/wiki/Mitsubishi_Kasei
The Mitsubishi Kasei (火星 Mars?) was a two-row, 14-cylinder air-cooled radial engine built by Mitsubishi Heavy Industries and used in a variety of World War II Japanese aircraft, such as Mitsubishi J2M and Mitsubishi G4M.[1]

First run 1938

MK4A [Ha-32] 11
1,530 horsepower (1,140 kW), 2450 rpm at takeoff
1,410 horsepower (1,050 kW), 2350 rpm at 1,000 metres (3,300 ft)
1,380 horsepower (1,030 kW), 2350 rpm at 4,000 metres (13,000 ft)

Diameter: 1,340 mm (53 in)
Dry weight: 780 kg (1,700 lb)

Valvetrain: push rod operated overhead-valve system with 2 valves per cylinder
Supercharger: centrifugal, two-speed single stage
Fuel system: Water-methanol injection
Cooling system: Air-cooled
Its first run was in 1938 and could have provided Germany with a similar engine to the BMW 801 without the overheating problem in 1938. This engine was roughly the same dimensions of the BMW 801, but was roughly 250kg lighter. Of course the Germans would probably tweek it to improve its performance, specifically its fuel injection system. It would have to be retuned to the 86 octane avgas the Germans used, instead of the 72 octane of the Japanese, which would boost performance. By 1940 this engine with tweeks would appear in production.
That give the Do 217 and FW190 projects a boost and ensures that without engine troubles they could appear in late 1940 (primarily the Do 217) or early/mid 1941 (Fw190).
The Do217 could carry 4 metric tons of bombs out to 1,400 miles with the BMW 801 of similar performance, which would be a nice addition to the bomber forces during the Blitz (obviously not decisive, but helpful the LW). The FW 190 entered into production historically in June 1941, but its production was somewhat delayed due to engine issues, issues that ultimately were not solved until 1942 and prevented the addition of the FW190 into serious operations until early 1942.

What effect would the early addition of an early FW190 be in the west and east? Would the Luftwaffe start phasing the Me109 out of service except for specialist units?

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Re: Germans buy Japanese radial engines?

#7

Post by phylo_roadking » 30 Aug 2012, 22:58

What effect would the early addition of an early FW190 be in the west and east? Would the Luftwaffe start phasing the Me109 out of service except for specialist units?
No.

For exactly the same reason as the British manufacturing the Spitfire and Hurricane together, and the Germans continued the 109 alongside the 190 until virtually the end of the war...

...total production numbers; fighting a multi-front war, attrition HAS to be countered, numbers built up etc. A new aircraft on a unmatured production line ONLY? No, you have two production lines....or rather two manufacuring conglomerates...producing as much as you can afford to produce and train pilots for...
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Re: Germans buy Japanese radial engines?

#8

Post by phylo_roadking » 30 Aug 2012, 23:08

Also - don't forget the issue of Japanese engines runnng out of puf at high altitudes ;) Yes the Germans can re-tune them for German fuel....but can they make them make full power right up at altitude??? Or will a Japanese-engined 190 give away a major advantage to the Spitfire and Hurricane? 8O
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Re: Germans buy Japanese radial engines?

#9

Post by stg 44 » 30 Aug 2012, 23:15

phylo_roadking wrote:Also - don't forget the issue of Japanese engines runnng out of puf at high altitudes ;) Yes the Germans can re-tune them for German fuel....but can they make them make full power right up at altitude??? Or will a Japanese-engined 190 give away a major advantage to the Spitfire and Hurricane? 8O
What's PUF?
Also in 1941-2 was there that much fighting at high altitudes?

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Re: Germans buy Japanese radial engines?

#10

Post by phylo_roadking » 30 Aug 2012, 23:51

What's PUF?
Puff lol

Remember what a turbosupercharger actually does - it pumps air into an engine so that the engine gets enough in any given instant to behave as if it's breathing nice thick oxygen-rich air down at sea level or just above :wink:
Also in 1941-2 was there that much fighting at high altitudes?
Not on the Eastern front, and not in the Pacific...but still over Western Europe, yes.

The point is - an aircraft that works well at low AND high altitude is fine at all heights up to its practical ceiling...

However, an aircraft that works fine at low and medium altitudes, but runs out of power increase at high altitudes - its power curve flattens....is disadvantaged at high levels ;)
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Re: Germans buy Japanese radial engines?

#11

Post by stg 44 » 30 Aug 2012, 23:58

Was the FW190 historically that good at higher altitudes in 1942? My understanding was that it excelled at lower to mid altitudes historically, so the problem with Japanese radials having problems at higher altitudes is somewhat moot if the German radials had the same problem. Historically the FW190 gave good service once its engine issues were sorted out, but still it was primarily for fighting at lower to middle altitudes.

Edit: it seems at even in 1943 there were still bombings (like POINT BLANK) at 14000 feet, which was well within the ceiling of the FW190, as at 20000 feet was where speed fell off.
Plus the RAF was fighting mainly at night in 1941-5 with daylight operations mostly below 20,000 feet as far as I can tell.

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Re: Germans buy Japanese radial engines?

#12

Post by phylo_roadking » 31 Aug 2012, 00:12

Was the FW190 historically that good at higher altitudes in 1942? My understanding was that it excelled at lower to mid altitudes historically, so the problem with Japanese radials having problems at higher altitudes is somewhat moot if the German radials had the same problem.
That's basically my point! http://forum.axishistory.com/viewtopic. ... 6#p1726963
Edit: it seems at even in 1943 there were still bombings (like POINT BLANK) at 14000 feet, which was well within the ceiling of the FW190, as at 20000 feet was where speed fell off.
Plus the RAF was fighting mainly at night in 1941-5 with daylight operations mostly below 20,000 feet as far as I can tell.
But you're concentrating on bombing; there was plenty of fighter-to-fighter combat with Fighter Command/Army Coop's "rhubarbs" and "circuses" in 1941 and 1942, fighters flying top cover for lower-level bombing missions, standing patrols etc...let alone massed air "battles" like over Dieppe.
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Re: Germans buy Japanese radial engines?

#13

Post by stg 44 » 31 Aug 2012, 00:18

My point is how does the addition of a lighter weight, earlier engine without overheating issues make the situation worse for the FW190? You've acknowledged that the German radials had the exact same issue as the Japanese radials, so there is no difference there; I'm not sure why the Japanese engines then would provide worse service than the German radials if both engines dropped off about 20k feet. As far as I can tell there would be no greater drop off than the German radials. Correct me if I'm wrong.

Yes, it wouldn't solve the altitude problem, I'm not arguing that. But in 1941-2 fighter and bomber combat was happening below 20,000 feet, even as the RAF may have flown top cover; the Spitfires would have to eventually dive to protect the lower flying bombers from fighters.

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Re: Germans buy Japanese radial engines?

#14

Post by phylo_roadking » 31 Aug 2012, 00:25

My point is how does the addition of a lighter weight, earlier engine without overheating issues make the situation worse for the FW190?
First of all - take a look at the example Mitsubishi engine you've used above; it first run in 1938....but how long was it after that that it went into series production in aircraft? :wink: Take a look at some WWII-era aero engines, you'll find 3, ....maybe even 5 year gestation times! 8O These benefits night simply not be available in any timescale benefitting the 190.
But in 1941-2 fighter and bomber combat was happening below 20,000 feet, even as the RAF may have flown top cover; the Spitfires would have to eventually dive to protect the lower flying bombers from fighters.
Ok, now I see the problem here - why do fighter pilots actually WANT altitude....or rather, MORE altitude than the aircraft they're attacking??? :wink:
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Re: Germans buy Japanese radial engines?

#15

Post by stg 44 » 31 Aug 2012, 00:31

phylo_roadking wrote:
My point is how does the addition of a lighter weight, earlier engine without overheating issues make the situation worse for the FW190?
First of all - take a look at the example Mitsubishi engine you've used above; it first run in 1938....but how long was it after that that it went into series production in aircraft? :wink: Take a look at some WWII-era aero engines, you'll find 3, ....maybe even 5 year gestation times! 8O These benefits night simply not be available in any timescale benefitting the 190.
My understanding was that first run meant first production run. Have I misunderstood?

phylo_roadking wrote:
But in 1941-2 fighter and bomber combat was happening below 20,000 feet, even as the RAF may have flown top cover; the Spitfires would have to eventually dive to protect the lower flying bombers from fighters.
Ok, now I see the problem here - why do fighter pilots actually WANT altitude....or rather, MORE altitude than the aircraft they're attacking??? :wink:
Of course the FW190 and ME109 could both operation at higher altitudes and most fighters shot down did not see the enemy. Speed doesn't matter as much when the enemy is flying information and not evasively. After the first surprise pass the FW190 dives and pulls the RAF fighters down to an altitude he has an advantage at. I'm not saying its perfect, but it seems to be the tactic used. Do you have any recommendations about the CIRCUS operations of 1941? I'm having a hard time finding more information about that period in the air war.

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