Ta-152C equivalent to Tempest?

[stona]

I don't know why people always compare things from different times. The Me262 from 1945 compared to the Meteor from the fifties.
cimmex

The best Time Between Overhaul (TBO) for any Jumo 004 was 30 hours. Both the Welland and Derwent, which were contemporary engines, had passed type tests of 500 hours and had a service TBO of 150 hours. I would suggest that this puts the Germans at a bit of a technical disadvantage, certainly in a practical, in service, front line sense.

BTW the B.41 'Nene' first ran at 5000lb thrust on 28th October 1944, so it is not a completely irrational comparison with the Jumo. Again, I'm not seeing a large German advantage a few years down the line.

As I said before this was largely due to the inferior materials that the German engines were being forced to incorporate in their construction. The German engineers made some very clever compromises but these drastically reduced the life of many vital components. I'm sure they would have liked a limitless supply of the alloys (like the Nimonic alloys used in the turbine blades and 'cans') being used by the British and Americans.

Cheers

Steve

 

[delcyros]

30 hours, more or less, yes.
It depends on the specific version, early B1 had less down to 7 to 10 hours, late B4 or D4 versions were somehow better at 50 hours (due to better fuel flow regulation, it was now more difficult to burn out the turbine blades by accelerating to fast). But 20 to 30 is a reasonable mean for most of the engines which saw service in 44 and early 45.
Still, I want You to keep in mind that You better not generalize the JUMO-004 data for all german jet engines. The design was choosen intentionally because it was a low risk design timely aviable. The better performing BMW-003, for example, had a significantly longer service lifetime than the JUMO-004. German jet engines had one very practical advantage over allied ones in this period: They could be relighted in flight after flame-out.
Dervent and RR after end of ww2 exploited the BMW-altitude jet engine test facilities and expertise of german engeneerers to finally sort their own problems with flame out, which frequenty beset 1st geneation jet engines, and allowed them safely to be relighted in flight.

The DB-company was running a dual flow, 2800lbs jet engine (Db-007) in 1943. It was abandoned, correctly because of complexity. I am also not certain that it could be relied on that the HeS011 would be bound for a successful design.
The german jet engine project was delayed by approx. 2.5 years due to the necessarity to find replacement but heat resistent materials and invent new cooling technologies (film cooling, hollow blade cooling with bleed air from the compressor) as well as sorting out harmonic vibration and the problems with automatic exhoust nozzle controll and fuel flow gouvernors.
After all, it was still a new technology.

 

[Shortround6]

What concentrating on the centrifugal compressor allowed the British and Americans to do was to work on all the other "stuff" " sorting out harmonic vibration and the problems with automatic exhoust nozzle controll and fuel flow gouvernors" combustion chambers, ignitors and so on. Granted there were design teams working on axial compressors in Britain and America Like Westinghouse.

"The Westinghouse J30, initially known as the Westinghouse 19XB, was a turbojet engine developed by Westinghouse Electric Corporation. It was the first American-designed turbojet to run, and only the second axial-flow turbojet to run outside of Germany.

They did get it up to 1600lbs of thrust in the Production version post war but with a 3 to 1 pressure ratio it had the same miserable fuel consumption as the German engines. Westinghouse was unable to capitalize on this early engine and their later engines fell increasingly behind their competitors ( both centrifugal and axial)

 

[Milosh]

Didn't the Metropolitan-Vickers F.2 run in Nov 1941. The 19XB first ran in March 1943.

 

[stona]

German jet engines had one very practical advantage over allied ones in this period: They could be relighted in flight after flame-out.

I would add the word 'theoretically' before 'be relighted in flight'. The accounts of many men who actually flew with the engines strongly suggests that it was rarely possible to accomplish this.

I think that the German engineers came up with some very clever solutions to overcome their lack of ideal materials, some of which you mentioned. These solutions might have enabled the engines to function but they did nothing for their longevity. For an engine in the hurly-burly of service life the TBO is an important factor and the TBO for the British engines is longer than the life of a Jumo 004. This is a significant problem in practical terms for units attempting to operate a type equipped with such engines. Serviceability rates for the Me 262 were, unsurprisingly, woeful.

The Me 262 had an Achilles heel and it was the power plants, under developed and unreliable.

It has often been said that pilots preferred a decent aeroplane which would allow them to fly relatively safely over a hot rod which was more likely to kill them than the enemy.

Cheers

Steve

 

[stona]

Didn't the Metropolitan-Vickers F.2 run in Nov 1941. The 19XB first ran in March 1943.

It did and is the grand daddy of the Armstrong Siddeley 'Sapphire' which ran in early 1948.

I think you mean the X19A which gave 1200 lb thrust. The 19XB was an engine derived from this which became the J 30 as mentioned above.

Cheers

Steve

 

[Milosh]

S6 said: "Westinghouse 19XB"

 

[stona]

S6 said: "Westinghouse 19XB"

S6 correctly referred to the Westinghouse 19XB as the predecessor of the J30 but it didn't run in 1943. The X19A did and I assumed that was the engine you were referring to. It did not become the J30, the 19XB, with an extra 400 lbs of thrust, did.

Just to confuse things almost exactly half of the 261 J30 engines produced were built by Pratt and Whitney, not Westinghouse

Cheers

Steve

 

[Milosh]

The Westinghouse J30, initially known as the Westinghouse 19XB....

He quoted Wiki. So Wiki needs to be corrected.

 

[stona]

The Westinghouse J30, initially known as the Westinghouse 19XB....

He quoted Wiki. So Wiki needs to be corrected.

No, that's right, the 19XB did become the J30. What it didn't do was run in 1943.

The X19A ran in 1943 and is a different engine (6-stage rather than 10 stage compressor and 400lbs less thrust for a start)

I haven't looked at the Wiki text, I'm looking at Gunston.

Cheers

Steve

 

[davparlr]

The US tried to get its P-80 into service in Italy in 1945, but it was totally non-operational due to engine issues.

Of the seven pilots killed in P-80s up to Aug. '45, two were caused by fuel pump failure although both had a backup fuel pump but were not operated properly by the pilot, one of these was Bong, one was caused by a midair collision, one was a failure of the tail pipe flange (this was one of the planes sent to Europe), one by over rotation and stall on takeoff, and one due to possible trim tab failure. An earlier, non-fatal, accident was caused by impure metal used in manufacturing of the turbine wheel. So, of the first seven fatal accidents of the P-80, none can be attributed to failure of the engine itself. One non-fatal accident that was an engine failure was a manufacturing quality problem. Additionally, the deployment to Europe was considered successful and the P-80 assumed rapid procurement. The one loss to these four was due to tail pipe separation. So I don't think your comment can be supported.

The Jumo 004H would have offered 3970 lbs thrust and been in service some time before the Nene, as it was just an enhancement of the 004 rather than a bigger Derwent, like the Nene was. Yes, the Nene would have been better than the Jumo 004H (though the Nene would have lost to the Jumo 012, which was a bigger 004 like the Nene was a bigger Derwent), but the Nene wouldn't fit on a Meteor, so would require a new jet fighter.

At the end of the war the Jumo 004H was only a few drawings and a pile of parts on the garage floor. It was nowhere near running much less meeting any performance requirements. The Nene had already been running for over six month with at least 4000 lbs thrust and probably 5000 lbs thrust. There is no way the 004H could have been developed faster than the Nene unless dangerous shortcuts were taken.

the Nene was a bigger Derwent), but the Nene wouldn't fit on a Meteor, so would require a new jet fighter.

Like the very capable Vampire?

German jet engines were ahead of the British ones by about a year or so. Even with the Jumo 004 being a dead end there were still developments of it that would have kept its edge if the war had gone on for a few more years until it could be replaced by something better, of which there were several other designs still having their problems worked out. I find it interesting that so many here seem to think that the post-war designs of the Allies were indications of their superiority of the Germans, while ignoring the other engines which also had not reached service yet that were under development with German firms. Comparing the Jumo 004 to post-war designs is not comparing apples to apples.

I think that German jet engine technology had fallen behind the Allies by the end of the war in thrust and thrust to weight. German jet aircraft integration was still ahead by six months or so and their theoretical aerodynamics was probably a year ahead, but not their engines, which hampered their advantage in aircraft integration.

That would have given the Jumo engine greater performance until 1946, by which time the Mark IV Derwent would be around, but then so would the 004H and probably the Jumo 012.

You mean the previously cancelled Jumo 012?

The P-80 was not able to get into service, despite being deployed to Italy in 1945; its engines were a mess and it couldn't even fly.

Not true.

The entire point of the Axial flow design was it was easier to get into service quickly, even though the Centrifugal design was more efficient; it was more difficult to get into service quickly and needed many more years to get it into widespread service.

The axial flow engine is much more complicated with multiple compressor stages. The reason the British had to catch up, and did, was because of the late start of the effort. If the Germans had started their work on the centrifugal compressor at the same time they did the axial, they would easily have been a year ahead of Britain, maybe more, an could have fielded much more powerful production jets much earlier than they did, in my opinion.

That was a first test, that means nothing about getting an engine ready for production and service. Otherwise the Jumo 222 would have been ready in 1941 along with the Jumo 004.

There is a huge jump between having a paper design and a production jet engine. A major hurdle is a working prototype, which, when it came to thrust improvements, the British and the Americans did, and the Germans DID NOT.

 

[drgondog]

The US tried to get its P-80 into service in Italy in 1945, but it was totally non-operational due to engine issues.
The P-80 was not able to get into service, despite being deployed to Italy in 1945; its engines were a mess and it couldn't even fly.

What you can say about the YP-80 is that few were deployed to ETO/MTO, one was lost due to the tailpipe failure, and as far as any documented example no air to air combat was experienced while deployed to Italy.

If you believe its engines 'were a mess' and 'it couldn't even fly' you should document why you think so - and elaborate why the USAAF was stupid to buy such a defective fighter.

 

[stona]

If you believe its engines 'were a mess' and 'it couldn't even fly' you should document why you think so - and elaborate why the USAAF was stupid to buy such a defective fighter.

.......More than 9,000 of all types and derivatives. Surely some of them could fly

Cheers

Steve

 

[silence]

so... yeah, about that Ta-152C thingy....

 

[Shortround6]

Well, we have thread creep and thread swerve or skew and then we have thread gallop and/or careen over a cliff.

 

[parsifal]

apparently not enough discussion material to comparre probably the best German piston engined fighter to the best allied piston engined fighter......hmmm

 

[davparlr]

Okay, back to the old thread. There is so little data on the Ta-152C and so few ever built that comparisons are difficult. The C appears to just be a slightly larger and more powerful Fw-190D-9. The first comment is that the Ta-152C, first flown Nov, '44, and the Tempest V and II are generations apart, the Tempest V first flying in Sept. '42, the II flying in June, '43. From my data (again limited on the Ta), shows that both Tempest versions would out perform the Ta 152C in speed and climb (although I have no really good climb data on the Ta), up to about 25k ft., the Tempest II being significantly so. Above 25k the Ta 152C begins to have the advantage in speed. Again my poor climb data shows the Ta 152C still struggles. As a side note, the Ta 152C contemporary, the P-47M, with its flat-rated 2800hp up to 33k, out performed the Ta 152C in both speed and climb from SL to ceiling, significantly so at altitude.

 

[delcyros]

I am not sure but the only primary data speed curves I have ever seen referring to Ta-152C0 performances based upon the DB-603L are referring to 1.75 ata and B4 fuel. 1.75 ata is roughly 2,240HP max. That´s not max power with MW-50 ("Sondernotleistung"=1.95ata with MW-50 injection, "Start-und Notleistung" 1.75ata for Db-603L without MW-50 injection). -just to keep in mind. Critical altitude should be lower and speed better with MW-50 at and below crit alt.
If compared with P47M, one should therefore use the curves without water injection, too. e.g. the curves with 54.5" instead of 72" hg. For these power ratings we do have comparable data, for MW-50 injection performances in the Ta-152C we would need to rely on speculation, which I would reject in absence of sources.

But aside from this, the example shows pretty clearly that the limit of piston engined A/C was approached by all powers. The only justifyable progress in performance loomed with jet propulsion.

 

[davparlr]

I am not sure but the only primary data speed curves I have ever seen referring to Ta-152C0 performances based upon the DB-603L are referring to 1.75 ata and B4 fuel. 1.75 ata is roughly 2,240HP max. That´s not max power with MW-50 ("Sondernotleistung"=1.95ata with MW-50 injection, "Start-und Notleistung" 1.75ata for Db-603L without MW-50 injection). -just to keep in mind. Critical altitude should be lower and speed better with MW-50 at and below crit alt.
If compared with P47M, one should therefore use the curves without water injection, too. e.g. the curves with 54.5" instead of 72" hg. For these power ratings we do have comparable data, for MW-50 injection performances in the Ta-152C we would need to rely on speculation, which I would reject in absence of sources.

I will admit to being significantly handicapped because I cannot read German. This also manifests itself in translating poor resolution copy, which I probably could if I knew what words were likely to apply. Anyway, the chart I was using is titled "Horizontalgeschwindigkeit uber der flughohe mit Sondernotleistung", and rates the Ta 152 C-1 with a DB 603LA engine but does indeed reflect B4 fuel and a 1.75 ata so your comments are valid.

But aside from this, the example shows pretty clearly that the limit of piston engined A/C was approached by all powers. The only justifyable progress in performance loomed with jet propulsion.

I fully agree.

 

[tomo pauk]

If I may ask something:
-"Sondernotleistung" will always mean that MW system is used; in case the fuel is B4, the manifold pressure is 1.75 ata max, in case C3 fuel is used, the manifold pressure is 1.95 max (for the DB-603LA)?
-What kind of manifold pressure was possible with C3 fuel only, ie. without using the MW-50?
-What are main differences between the 603L and 603LA engines?
-No matter whether C3 or B4 fule is used, the power will be about the same above 10,5 km (with full ram)?