What would a "Best of the lot" 1943 fighter aircraft look like?

Deleted member 1487

I'd removed the rear fuel tank (install two fuel tanks in wings to compensate for that) so the cooling system can be mostly burried in the fusealge, like it was the case with P-51 and a number of ww2 aircraft. The 2-stage S/C from Merlin will indeed give a fine hi-alt performance to the DB-603, though the 2-stage S/C from Griffon to cater for the needs of a bigger engine.
What was the state of the Griffon and it's supercharger as of 1943?
 

hipper

Banned
What was the state of the Griffon and it's supercharger as of 1943?

From Wikipedia but this is what's available through 1943

  • Griffon IIB
1,730 hp (1,290 kW) at 750 ft (230 m) and 1,490 hp (1,110 kW) at 14,000 ft (4,270 m); Single-stage two-speed supercharger; impeller diameter 10 in (25.4 cm); gear ratios 7.85:1, 10.68:1.[20] Used on Firefly Mk.I and Spitfire XII.
  • Griffon VI
Increased maximum boost pressure, 1,850 hp (1,380 kW) at 2,000 ft (610 m); impeller diameter 9.75 in (24.7 cm).[20] Used on SeafireMk.XV and Mk. XVII, Spitfire XII.

A Rolls-Royce Griffon 58 displayed at the Shuttleworth Collection (2008)
  • Griffon 61
Introduced a two-speed two-stage supercharger with aftercooler similar to that on Merlin 61; 2,035 hp (1,520 kW) at 7,000 ft (2,100 m) and 1,820 hp (1,360 kW) at 21,000 ft (6,400 m); used on Spitfire F.Mk.XIV, Mk.21.
 
Thanks. So it's basically using a Merlin supercharger. So that's the one we'd want to mate to the DB603A if possible.

I think our 'best of' fighter in 1943 has to use either the Twin Wasp or a Griffon - both were rated for 'high knock' so could use higher octane fuels - Griffon 65 used 150 octane fuel by wars end (apparently it was bright green!)
 

Deleted member 1487

I think our 'best of' fighter in 1943 has to use either the Twin Wasp or a Griffon - both were rated for 'high knock' so could use higher octane fuels - Griffon 65 used 150 octane fuel by wars end (apparently it was bright green!)
Depends on their stage of development. The DB603N beat the Griffon with equivalent fuel:
https://en.wikipedia.org/wiki/Daimler-Benz_DB_603#Prototypes_and_other_versions
  • DB 603N (prototype with two-stage supercharger, C3 fuel)
Power (take-off): 3000PS (2958 hp, 2206 kW) at 3200 rpm at sea level
Power (max): 2570 PS (2762 hp, 2059 kW) at 3000 rpm at sea level
Continuous: 1930 PS (1904 hp, 1420 kW) at 2700 rpm at sea level

https://en.wikipedia.org/wiki/Rolls-Royce_Griffon
Performance
  • Power output:
  • 2,035 hp (1,520 kW) at 7,000 ft (2,135 m MS gear),[nb 7] +18 psi boost pressure at 2,750 rpm
  • 2,220 hp (1,655 kW) at 11,000 ft (2,135 m MS gear), +21 psi at 2,750 r.p.m using 150 Octane fuel
  • 1,820 hp (1,360 kW) at 21,000 ft (6,400 m) at 2,750 rpm
  • Specific power: 0.91 hp/in3 (41.4 kW/L)
  • Compression ratio: 6:1
  • Power-to-weight ratio: 1.03 hp/lb (1.69 kW/kg)

The Twin Wasp was a max 1200hp engine. I think you mean the Double Wasp:
https://en.wikipedia.org/wiki/Pratt_&_Whitney_R-2800_Double_Wasp
It was mostly a 2000 or so HP engine by 1944. IIRC it was putting out 1800hp in 1943.
 
Just a mention that, in 1943, the RR Vulture had pretty well solved it's problems and was fit to go into a Tempest and the OTL Tempest was not so far from a Fury so it is not impossible to have a Fury entering service in 1943 with a Vulture. The Tornado had flown with a Vulture in 1939.
 

Deleted member 1487

Just a mention that, in 1943, the RR Vulture had pretty well solved it's problems and was fit to go into a Tempest and the OTL Tempest was not so far from a Fury so it is not impossible to have a Fury entering service in 1943 with a Vulture. The Tornado had flown with a Vulture in 1939.
https://en.wikipedia.org/wiki/Focke...istory#Comparison:_Fw_190D_and_Hawker_Tempest
Comparison: Fw 190D and Hawker Tempest
Shortly after the war the British became interested in the performance and evaluation of the advanced German Fw 190 D-13. While at Flensburg the British Disarmament Wing wanted to see how this fighter would perform against one of their best, a Hawker Tempest. Squadron Leader Evans approached Major Heinz Lange and asked him to fly a mock combat against one of their pilots. Lange accepted, even though he had only 10 flights in a D-9.[80] The mock dogfight was conducted at an altitude of 10,000 ft (3,000 m), with only enough fuel for the flight and no ammunition. In the end the machines were evenly matched. Major Lange assessed that the outcome of such a contest greatly depended on the skills of the individual pilot. At the time Lange was not aware that he was not flying a D-13 but rather a D-9. The same "Yellow 10" (Wk. Nr. 836017) that was previously assigned to Geschwaderkommodore Franz Götz was used in this evaluation. "Yellow 10" was further subjected to mock combat when on 25 June 1945 Oberleutnant Günther Josten was asked to fly a comparison flight against another Tempest.[80]
 

Wimble Toot

Banned
Alternative history/aviation fans!

Seventy-three years ago today, the Supermarine model 379 Spitfire Mk XIV shot down its first Me262.

610sqdn-spit14.jpg


ALL HAIL!
 
Thanks. So it's basically using a Merlin supercharger. So that's the one we'd want to mate to the DB603A if possible.

Griffon used bigger supercharger than Merlin, with an accordingly bigger intercooler - more power means it needs more air. Diameters of the 1st and 2nd stage impellers were 13.4 in and 11.4 in respectively, vs. 2-stage Merlin with 12 in and 10 in.

Depends on their stage of development. The DB603N beat the Griffon with equivalent fuel:
https://en.wikipedia.org/wiki/Daimler-Benz_DB_603#Prototypes_and_other_versions

It is 1943 we're talking about. The 603N was in prototype phase in 1945, just like the Griffon 100 series. Even the predecessor, the 603L, was barely available in 1944 apart for testing and as zero-series engine. No German-language source claims that 603N went above 3000 rpm either, unlike the English-language Wikipedia.

The Twin Wasp was a max 1200hp engine. I think you mean the Double Wasp:
https://en.wikipedia.org/wiki/Pratt_&_Whitney_R-2800_Double_Wasp
It was mostly a 2000 or so HP engine by 1944. IIRC it was putting out 1800hp in 1943.

R-2800 was making 1850 HP before 1942, and 2000 HP from December 1941/January 1942. That is production engines, not prototypes. In 1942, some 1080 copies of 2-stage supercharged R-2800s were produced, vast majority for the needs of F4U and F6F.
 
http://www.spitfireperformance.com/spit14v109.html

not a lot to choose from between these two aircraft. It should come down to pilot quality.

In 1943 we can choose the Spit 14, but there is no 109K to choose since it is about a year too late for this thread.


The 'G-Lader' (spiral supercharger) was never installed in a service-worthy DB-603. Thus it is 670-680 km/h for an armed Fw 190C, while the chart represents un-armed ('ohne Waffen') test bed.
 

Deleted member 1487

Griffon used bigger supercharger than Merlin, with an accordingly bigger intercooler - more power means it needs more air. Diameters of the 1st and 2nd stage impellers were 13.4 in and 11.4 in respectively, vs. 2-stage Merlin with 12 in and 10 in.
Which version of it? It stands to reason it would be bigger, but the article says that that specific model used a Merlin supercharger.

It is 1943 we're talking about. The 603N was in prototype phase in 1945, just like the Griffon 100 series. Even the predecessor, the 603L, was barely available in 1944 apart for testing and as zero-series engine. No German-language source claims that 603N went above 3000 rpm either, unlike the English-language Wikipedia.
Sure and the engines referenced with not 1943 versions. Also the DB603N was cancelled in 1944 due to C3 fuel shortages; it was supposed to enter production that year.
The constraint German engines had was the lack of access to C3 fuel and heat resistance metals, while the Allies could and did build their engines without shortage. Like the DB605 ASC(M) was 2000hp with C3 high performance fuel...of which there was virtually none by mid-1944 due to bombing of the facilities making them, which then kept a lot of prototypes that were ready for mass production in permanent prototype status due to lack of required fuel, while Allied versions were pumped out.

Since we aren't talking about OTL here per OP, I'm not considering production ready prototypes a constraint for options.

R-2800 was making 1850 HP before 1942, and 2000 HP from December 1941/January 1942. That is production engines, not prototypes. In 1942, some 1080 copies of 2-stage supercharged R-2800s were produced, vast majority for the needs of F4U and F6F.
Ok. What is the source on that? I haven't been able to find years to associate with performance and am interested in finding more sources.
 
Which version of it? It stands to reason it would be bigger, but the article says that that specific model used a Merlin supercharger.

The model I'm talking about is the Mk.65, data taken from an article in the 'The Aeroplane'.
Wikipedia can be unreliable and/or imprecise on techincal issues, the article said that supercharger and intercooler were 'similar to that on Merlin 61', not 'taken out from Merlin' however.

Sure and the engines referenced with not 1943 versions. Also the DB603N was cancelled in 1944 due to C3 fuel shortages; it was supposed to enter production that year.
The constraint German engines had was the lack of access to C3 fuel and heat resistance metals, while the Allies could and did build their engines without shortage. Like the DB605 ASC(M) was 2000hp with C3 high performance fuel...of which there was virtually none by mid-1944 due to bombing of the facilities making them, which then kept a lot of prototypes that were ready for mass production in permanent prototype status due to lack of required fuel, while Allied versions were pumped out.

Since we aren't talking about OTL here per OP, I'm not considering production ready prototypes a constraint for options.

(my bold)
The Griffon with 2-stage S/C was available in 1943. DB-603N was in prototype stage in 1945, ie. it was not cancelled in 1944.
I'll also disegree with the bolded part - Germany of ww2 dropped the ball by not developing 2-stage supercraged versions of their engines until too late. There were at least two powerful engines for all altitudes that were rated for 87 oct fuel - Jumo 213E and DB 603LA - but those were too late to matter. Plus, if the Allies have had plenty of hi-oct fuel, the German V12 engines were of much greater cubic capacity to cancel the Allied advantage.
It might be also good to remember that German engineers were quick to score own goals with going for increased compression ratio, a thing that negated plenty of benefits of hi-oct fuel.
That is all, before I drift too much at off-topic field.

Ok. What is the source on that? I haven't been able to find years to associate with performance and am interested in finding more sources.

This e-book is simply excellent: link.
Table on the page 104 shows engines delivered by P&W main factory in Connecticut. The 'B' series of the R-2800 was rated for 2000 HP in 1942. The 'A' series engines, used on military aircraft, were good for 1850 HP. More here.
 

Deleted member 1487

The model I'm talking about is the Mk.65, data taken from an article in the 'The Aeroplane'.
Wikipedia can be unreliable and/or imprecise on techincal issues, the article said that supercharger and intercooler were 'similar to that on Merlin 61', not 'taken out from Merlin' however.
The Griffon 65 was a 1944 engine however, entering service with the Spit F.MarkXIV to hunt V-1s based on what I can find online.
Fair point about the Griffon 61, but that doesn't say how exactly it was different.

(my bold)
The Griffon with 2-stage S/C was available in 1943. DB-603N was in prototype stage in 1945, ie. it was not cancelled in 1944.
It was a prototype not undergoing further development for lack of the necessary fuel.

I'll also disegree with the bolded part - Germany of ww2 dropped the ball by not developing 2-stage supercraged versions of their engines until too late. There were at least two powerful engines for all altitudes that were rated for 87 oct fuel - Jumo 213E and DB 603LA - but those were too late to matter. Plus, if the Allies have had plenty of hi-oct fuel, the German V12 engines were of much greater cubic capacity to cancel the Allied advantage.
It might be also good to remember that German engineers were quick to score own goals with going for increased compression ratio, a thing that negated plenty of benefits of hi-oct fuel.
That is all, before I drift too much at off-topic field.
Any idea why they did not focus more development on two stage superchargers?
As to the compression ratios...wasn't that the point of high performance fuels? They had higher resistance to detonation from pressure, so you could compress them more to achieve more efficiency in piston performance?

This e-book is simply excellent: link.
Table on the page 104 shows engines delivered by P&W main factory in Connecticut. The 'B' series of the R-2800 was rated for 2000 HP in 1942. The 'A' series engines, used on military aircraft, were good for 1850 HP. More here.
Thank you
 
The Griffon 65 was a 1944 engine however, entering service with the Spit F.MarkXIV to hunt V-1s based on what I can find online.
Fair point about the Griffon 61, but that doesn't say how exactly it was different.

I've checked at Lumsden's book bout the British engines, he states for the Griffon 61 to have one impeller of 13.4 in, another 11.3 in of diameter.

It was a prototype not undergoing further development for lack of the necessary fuel.

I'm afraid that WAllied troops entering Bavaria in 1945 cancelled the DB 603N, along with many other projects there.

Any idea why they did not focus more development on two stage superchargers?
As to the compression ratios...wasn't that the point of high performance fuels? They had higher resistance to detonation from pressure, so you could compress them more to achieve more efficiency in piston performance?

What you've said is true for an non-supercharged engine.
In supercharged engines, the compressor does plenty of the compressing, trying to ram as much of the air in cylinders as possible. Compressed air is very hot, and is further heated du to engine compression, so it might spontaneously ignite the fuel-air mixture much before the piston reaches the top dead position, thus trying to revert the engine rotation with cathastrophic result. Hi-oct fuel will not be so easily ignited, 'waiting' for the spark plug to make the spark when piston is in proper position.
The increased CR here is a problem since the air-fuel mixture will undergo the increased in-engine compression, with now greater temperature rise, so sponatneous ignition might happen even if the hi-oct fuel is used. That defeats the main benefit of using the hi-oct ratio - increasing the boost. Increased boost (= we have more air rammed in the engine) increases the power in more or less linear fashion. Increased CR barely increases power.
We might recall that most of the times German engines went for increased CR, the reliability suffered - DB 601N, BMW-801D, DB 605AS, even the DB 603A was unreliable during it's 1st year.
 

Deleted member 1487

What you've said is true for an non-supercharged engine.
In supercharged engines, the compressor does plenty of the compressing, trying to ram as much of the air in cylinders as possible. Compressed air is very hot, and is further heated du to engine compression, so it might spontaneously ignite the fuel-air mixture much before the piston reaches the top dead position, thus trying to revert the engine rotation with cathastrophic result. Hi-oct fuel will not be so easily ignited, 'waiting' for the spark plug to make the spark when piston is in proper position.
The increased CR here is a problem since the air-fuel mixture will undergo the increased in-engine compression, with now greater temperature rise, so sponatneous ignition might happen even if the hi-oct fuel is used. That defeats the main benefit of using the hi-oct ratio - increasing the boost. Increased boost (= we have more air rammed in the engine) increases the power in more or less linear fashion. Increased CR barely increases power.
We might recall that most of the times German engines went for increased CR, the reliability suffered - DB 601N, BMW-801D, DB 605AS, even the DB 603A was unreliable during it's 1st year.
So how did the Allies do it?
And why did the Germans not focus on 2 stage supercharging?
 
So how did the Allies do it?

How did they do what exactly?

And why did the Germans not focus on 2 stage supercharging?

Who knows - perhaps they were of opinion that 1-stage supercharged engines will do it?
Junkers was making stratosphere flights in 1930s with aircraft powered by engines with 2- and even 3-stage compressors - that is two or three impellers in series. Intecooler was also incorporated. Well-known were also Bristol's stratosphere flights, their powerplants featured a separate compressor stage that could be clutched in above certain altitude, while Junkers engines featured more compact layout of impellers. Farman (company) made known their design for 2-stage S/C in 1937 for all the word to see.
The DB 601C and D engines were to be 2-stage supercharged, however nothing came out from that.
We can also recall that neither Bristol nor Napier didn't produced a 2-stage supercharged engine, apart from possible prototypes, for ww2.
 

Deleted member 1487

How did they do what exactly?
Achieve higher compression ratios than the Germans were able to.

Who knows - perhaps they were of opinion that 1-stage supercharged engines will do it?
Junkers was making stratosphere flights in 1930s with aircraft powered by engines with 2- and even 3-stage compressors - that is two or three impellers in series. Intecooler was also incorporated. Well-known were also Bristol's stratosphere flights, their powerplants featured a separate compressor stage that could be clutched in above certain altitude, while Junkers engines featured more compact layout of impellers. Farman (company) made known their design for 2-stage S/C in 1937 for all the word to see.
The DB 601C and D engines were to be 2-stage supercharged, however nothing came out from that.
We can also recall that neither Bristol nor Napier didn't produced a 2-stage supercharged engine, apart from possible prototypes, for ww2.
I know intercoolers were expensive and somewhat complex to include, so perhaps it was just cost?
 
Achieve higher compression ratios than the Germans were able to.

Allies were using lower compression ratios than Germans. RR used 6:1 from supercharged Kestrel to Griffon (almost a 20 year span), V-1710 was at 6.65:1 (so we see Merlins using greater boost than V-1710s in most of the cases = more power for the Merlin). Of the German enfgines, Jumo engines were with lowest CR, 6.5.1 for vast majority of the types.

I know intercoolers were expensive and somewhat complex to include, so perhaps it was just cost?

Intercoolers are inexpensive. Air-to-air intercoolers are even less expensive than water-to-air types, and simple - Jumo 211J used the air-to-air intercoolers, so did the American-designed engines where applicable (I'm not counting prototypes).
New, 'clean sheet' engine is much more expensive than additon of an improved S/C to an existing type.
 

Deleted member 1487

Allies were using lower compression ratios than Germans. RR used 6:1 from supercharged Kestrel to Griffon (almost a 20 year span), V-1710 was at 6.65:1 (so we see Merlins using greater boost than V-1710s in most of the cases = more power for the Merlin). Of the German enfgines, Jumo engines were with lowest CR, 6.5.1 for vast majority of the types.
How did they get improved performance out of the fuel then?

Intercoolers are inexpensive. Air-to-air intercoolers are even less expensive than water-to-air types, and simple - Jumo 211J used the air-to-air intercoolers, so did the American-designed engines where applicable (I'm not counting prototypes).
New, 'clean sheet' engine is much more expensive than additon of an improved S/C to an existing type.
Why weren't they used more then in German designs? AFAIK the Jumo 211J was the first that had one.
 
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