Could the Jumo 004 project have been started in 1937?

[wuzak]

Perfectly correct. It took years further development to get axial flow engines up to same levels of power, fuel economy and power as the centrifugal ones.

Au contraire. The Metropolitan-Vickers F.2 was both more powerful and more economical (lower sfc) than the equivalent era centrifugal flow engines.

Its problems were weight (680kg vs 385kg), reliability and complexity. The complexity caused manufacturing problems.

Plus, whole new manufacturing technologies had to be developed, instead of being to springboard off of the existing supercharger manufacturing.

I would think that in some ways that was not the case. The British centrifugal gas turbines all still used an axial flow turbine, so that was the same for both.

The blades for an axial flow compressor are, in some ways, similar to turbine blades. They are aerodynamic profiles, which have to be formed by some method.

The difficulty with axial flow compressors was matching each of the stages to avoid surging and/or stalling of individual stages.

Also, as work on centrifugal compressors progressed they too became more complicated and required new construction techniques.

 

[wiking85]

Other way around. Junkers engineers went to Heinkel-Hirth, where they developed the 109-006 (HeS 30) along side von Ohain's HeS 3.

The HeS 30 was cancelled in favour of the 109-011 (aka HeS 011), which incorporated axial and centrifugal (actually "diagonal") compressor stages.

What about the Germans keeping the HeS 30 program going? From what I've been reading it could have been in service in 1943.

 

[Shortround6]

They were aware of the concept of embedding the engine in the fuselage to reduce drag. The problem was two-fold, the first being the lack of apreciable thrust-to-weight and the other was they were simply out of time in regards to development.

A few examples:
Messerschmitt P.1101 which ironically, had a HeS 011A
Focke-Wulf Ta183 which was designed for the HeS 011 or Jumo 004

Putting two early centrifugal engines in the fuselage took up too much room and would leave little space for other things, like fuel. The centrifugal engines being about 3 1/2-4ft in diameter.

The two examples you provide used a single engine that was NOT a centrifugal

And was supposed to offer 2700lbs thrust which is around 50% more than what some of the earlier engines were offering.

 

[nuuumannn]

The axial flow compressor idea goes back to before WW I for naval and industrial use (shaft turbine). While more than a "theoretical" concept it wasn't of much use as the best of the experimental rigs could barely keep themselves running let alone actually provide power to do something (propel ship, run generator, run fans for steel mills, etc).

I'm paware of the non-aviation use of axial flow engines prior to 1937 (Parson and his Turbinia at the Spithead Review - naturally), Shortround and would have thought you might have had the prescience to figure out that it was in reference to the use of axial flow engines in aircraft, that I mentioned their theoretical use, but I guess not.

What about the Germans keeping the HeS 30 program going?

Possibly, but from what I've read, the RLM cancelling the He S 30 in 1942 was as much a political decision as it was because the Jumo 004 was producing greater thrust at an earlier stage of development than the He S 30. After Max Muller left Heinkel in May '42, Heinkel with the aid of Wagner's team from Junkers worked on the He S 011, but its development was quite protracted and by 1945 whilst under test in a Ju 88 it could not manage its projected thrust output.

See the picture that Shortround posted above; That's an He S 011; it had a combined centrifugal/axial compressor, visible in the cutaway.

 

[wuzak]

Basic Data for Heinkel-Hirth 109-006 (HeS 30)

Planned Thrust: 1125kp (2481lb) @ 800km/h (497mph)
Thrust Obtained: 860kp (1896lb) to 910kp (2006lb) static thrust
Speed: 10,500rpm
Weight: 390kg (860lb)
Pressure Ratio: ~3:1
Diameter: 0.62m (24-3/8")
Length: 2.72m (107-1/8")

Data for Heinkel-Hirth 109-011 (HeS 011)

Thrust: 1300kp (2867lb)
Speed: 11,000rpm
Weight: 950kg (2095lb)
Height: 1.08m (42-1/2")
Width: 0.864m (34")
Length: 3.455m (136")


Data for 109-004 B-0 (Jumo 004 B-0)

Thrust: 840kp (1848lb) static
Speed: ~8700rpm
Weight: 730-750kg (1610-1654lb)
Diameter: 0.96m (37-3/4")
Length: 3.80m (149-5/8")


Data for 109-004 B-1 (Jumo 004 B-1)

Thrust: 900kp (1985b) static
Speed: ~8700rpm
Weight: 720kg (1588lb)
Diameter: 0.80m (31-1/8")
Length: 3.864m (152-1/8")


Data for 109-004 C (Jumo 004 C)

Thrust: 1000kp (2205b) static
Speed: ~8700rpm
Weight: 720kg (1588lb)
Diameter: 0.755m (29-3/4")
Length: 3.83m (150-3/4")


Data for 109-003 A-0 (BMW 003 A-0)

Thrust: 800kp (1764b) static
Speed: 9500rpm
Weight: 570kg (1257lb)
Diameter: 0.690m (27-1/8")
Length: 3.565m (140-3/8")

Data from Antony L. Kay, German Jet Engine and Gas Turbine Development 1930-1945.

It would seem that the 109-006 was not lacking for thrust when compared with its contemporaries, the 109-003 and 109-004, considering that it had only had a few bench tests when it was cancelled.

 

[GrauGeist]

Putting two early centrifugal engines in the fuselage took up too much room and would leave little space for other things, like fuel. The centrifugal engines being about 3 1/2-4ft in diameter.

The two examples you provide used a single engine that was NOT a centrifugal

And was supposed to offer 2700lbs thrust which is around 50% more than what some of the earlier engines were offering.

My post was in regards to the embedding of the engine in the fuselage as opposed to external nacelles and they were designed for a single engine and I'm fairly sure I never specified axial or centrifuge.

 

[wuzak]

Other way around. Junkers engineers went to Heinkel-Hirth, where they developed the 109-006 (HeS 30) along side von Ohain's HeS 3.

The HeS 30 was cancelled in favour of the 109-011 (aka HeS 011), which incorporated axial and centrifugal (actually "diagonal") compressor stages.

Reading a bit further, work on the 109-006 did indeed begin at Junkers before development of the 109-004 commenced, but the latter borrowed nothing from the former. Parallel developments, you might say.

 

[Shortround6]

I'm paware of the non-aviation use of axial flow engines prior to 1937 (Parson and his Turbinia at the Spithead Review - naturally), Shortround and would have thought you might have had the prescience to figure out that it was in reference to the use of axial flow engines in aircraft, that I mentioned their theoretical use, but I guess not.

The Turbina used a steam turbine. As a "turbine" engine it leaves a lot to be desired trying to compare it to a "gas" turbine engine unless you count the fans pressurizing the stoke hold as compressors.

The Turbina replaced reciprocating pistons with an axial flow turbine, the boilers stayed the same.

People were working with gas turbine engines before WW I, that is engines that sucked in air, compressed it using an axial flow compressor (and other compressor types) , injected fuel into the air stream and burned it in a combustion chamber and sent the exhaust through a power turbine that was used to drive the compressor. They were trying to get usable power out of a drive shaft rather than use the exhaust gas for propulsion but much, much closer to an aircraft turbine in basic operating theory than a steam turbine and boiler.

The getting the gas turbine (internal combustion engine) to run on it's own turned out to be a bit difficult compared getting a steam turbine ( external combustion engine) to produce power.

 

[Shortround6]

My post was in regards to the embedding of the engine in the fuselage as opposed to external nacelles and they were designed for a single engine and I'm fairly sure I never specified axial or centrifuge.

The Hes 011 was a later engine with more power, it was much more suitable for a single engine installation. The earlier engines of 1000-2000lbs thrust needed two engine to give the needed performance and once you are into two engine than the diameter of each engine becomes more important. Germans went with the axial compressor not just because of the smaller diameter/lower drag but it was one of the reasons. The fact that a later engine allowed a single engine option with the desired performance doesn't change the reasons for the earlier decision.

 

[Milosh]

I would say the steam turbine would be closer to a turbo-prop engine.

 

[GrauGeist]

The fact that a later engine allowed a single engine option with the desired performance doesn't change the reasons for the earlier decision.

The He178 kind of disproves that theory

 

[Shortround6]

Actually it kind of proves it

Rather lacking in room for fuel or armament. Useful proof of concept, lousy fighter prototype. Gloster E.28/39 wasn't any better.

 

[GrauGeist]

Wasn't intended to be a fighter, it was, as stated, intended as a proof of concept. It perfomed to that end well.

The point I was making was that the Germans were aware of parasitic drag caused by external engine housings and were in the process of migrating the engines into the fuselage. The two airframes I previously mentioned were intended for a single engine, the second generation Me262 (HG series) was to have the engines (2) embedded as well.

 

[pattern14]

Wasn't intended to be a fighter, it was, as stated, intended as a proof of concept. It perfomed to that end well.

The point I was making was that the Germans were aware of parasitic drag caused by external engine housings and were in the process of migrating the engines into the fuselage. The two airframes I previously mentioned were intended for a single engine, the second generation Me262 (HG series) was to have the engines (2) embedded as well.

Spot on there GrauGeist. If you look at the me 262 development programme, and there is a truckload of info on this plane, the proposed HG model had better aerodynamics, streamlined inlet ducts at the wing roots and much improved performance. Even Professor Willy himself saw the production model as an "interim" design, but the fortunes of war made it operational as it was. There were other Luftwaffe single engine jet fighters very close to being produced, with better performance again, but time ran out. In terms of applied aerodynamics, the German engineers had the jump, even if the rest were catching up fast. The He 162 was a failure operationally, and something of a desperation dead end design, but still the only single engine jet fighter to see combat. Its' performance was better than the 262 as well. As for the He 178, it really was proof of concept, even if the Nazi leadership took little interest. Frank Whittle had similar disinterest shown to him by the British Government, and his prototype was a flying test bed as well. They were both never intended to be anything else.

 

[OldSkeptic]

Spot on there GrauGeist. If you look at the me 262 development programme, and there is a truckload of info on this plane, the proposed HG model had better aerodynamics, streamlined inlet ducts at the wing roots and much improved performance. Even Professor Willy himself saw the production model as an "interim" design, but the fortunes of war made it operational as it was. There were other Luftwaffe single engine jet fighters very close to being produced, with better performance again, but time ran out. In terms of applied aerodynamics, the German engineers had the jump, even if the rest were catching up fast. The He 162 was a failure operationally, and something of a desperation dead end design, but still the only single engine jet fighter to see combat. Its' performance was better than the 262 as well. As for the He 178, it really was proof of concept, even if the Nazi leadership took little interest. Frank Whittle had similar disinterest shown to him by the British Government, and his prototype was a flying test bed as well. They were both never intended to be anything else.

Good point. Basically the British had the better engines, while the Germans had the better airframe (with the possible exception of the DH Vampire).

 

[wiking85]

Good point. Basically the British had the better engines, while the Germans had the better airframe (with the possible exception of the DH Vampire).

Only due to the lack of access to quality metals. If say the HeS 30 was built, then the British would have had inferior engines, but with metals being a concern and the Jumo 004 being designed around not having much of quality, it got the production nod.

 

[Shortround6]

Wasn't intended to be a fighter, it was, as stated, intended as a proof of concept. It perfomed to that end well.

The point I was making was that the Germans were aware of parasitic drag caused by external engine housings and were in the process of migrating the engines into the fuselage. The two airframes I previously mentioned were intended for a single engine, the second generation Me262 (HG series) was to have the engines (2) embedded as well.

As I said, in the early planning stages it looked like two engines would be needed to get the required thrust for a service fighter ( actual armament and worthwhile endurance). A BMW 003 A2 had a diameter of 27.2in and a frontal area of 4 sq ft. The Jumo 004 B4 had a diameter of 29.9in and a frontal area of 4.9 sq ft. A R-R Welland had a diameter of 43 in and a frontal area of 10.1 sq ft. The Derwent is about the same. The engine used in the He 178 had a diameter of about 36.3 in and a frontal area of about 7.3 sq ft.
Obviously an axial flow compressor engine would offer much less frontal area and drag than a Centrifugal one. The Germans biased their programs to the axial engines.
Once the engines began to show more power then single engine fighters could be considered.

Things were changing faster in the jet engine sector than in the piston engine sector. But since production decisions often have to be made months if not 1 -2 years before production starts old programs or old decisions often influence things for a number of years.

 

[OldSkeptic]

Only due to the lack of access to quality metals. If say the HeS 30 was built, then the British would have had inferior engines, but with metals being a concern and the Jumo 004 being designed around not having much of quality, it got the production nod.

Nope. It was because the British went (correctly) for a centrifugal design, which could be levered off the well developed supercharger experience, knowledge and manufacturing ability.

The Germans went for the theoretically better axial flow, but that involved far more engineering and production challenges.
It took years more work for the British and Americans (despite having all the materials available) to create axial flow engines of comparable power/weight/economy/reliability as the increasingly well developed centrifugal ones.

Read Hooker's book (Not Much Of A Engineer) about how heartbreaking it was to solve the challenges of getting an axial flow engine working and this was after he and his team had developed the 5,000lb centrifugal Nene in only a few months.

The HeS 30 was way too ambitious a design, a real "what were they thinking" job. If the war had gone onto 1950 then it might have been useful.... though it was well outperformed by the later 4,000lb Derwent V ( a scaled down Nene) In fact even the Derwent IV (2,400lb thrust) had a higher power to weight ratio.