Fw190C technical question

[wiking85]

Why did this adaptation fail while the FW190D succeeded? My understanding was the 'kangaroo pouch' turbosupercharger had too many problems so they dropped it and moved on to the D and Ta-152. But why didn't they go for a supercharger like they did with the 190D? Also why didn't they go for a medium altitude FW190C without pouch? Could they have had a low/medium altitude fighter like the Hawker Typhoon in 1943 had they continued with a turbosupercharger-less Fw190C?

 

[tomo pauk]

Why did this adaptation fail while the FW190D succeeded?

Don't think that Fw 190C 'failed' - it just was not pursued. Saying that Fw 190D-9 was success requires a good leap of faith IMO, it was way too late in fray, and did not brought performance parity vs. best of the Allied fighters, while sacrificing the heavy punch the Antons have had.
There were two 'lines' of the Fw 190C - turboed and non-turboed, BTW.

My understanding was the 'kangaroo pouch' turbosupercharger had too many problems so they dropped it and moved on to the D and Ta-152. But why didn't they go for a supercharger like they did with the 190D?

The turbocharger installation was too draggy, eating all of performance gain vs. the bread'n'butter DB 603A installation. The DB 603 already have had (the gear-driven, or engine-driven) supercharger, as any ww2 piston engine worth talking about.

Also why didn't they go for a medium altitude FW190C without pouch? Could they have had a low/medium altitude fighter like the Hawker Typhoon in 1943 had they continued with a turbosupercharger-less Fw190C?

Why there was no 'plain' Fw 190C? Answer might be two-fold: the engines were earmarked for the Me 410 and Do 217 (same as the Jumo 213A was earmarked for the Ju 188), while brass (both in LW and RLM) was probably of opinion that radial-engined Fw 190 can do the job on un-escorted bombers, as it was the case in 1943 and earlier. The DB 603 A was having reliability problems during the best part of 1943, so this might've influenced stuff.

The Fw 190C would've been every bit as good as Fw 190D, perhaps even better since it would be possible to install the prop cannon, hence increasing the firepower vs. cowl HMGs, while cutting the drag in the same time.

 

[wiking85]

BTW what's the difference between a clean Fw190C and the Ta-152C?

 

[tomo pauk]

By clean you probably mean that it has no turbo and it's anciliaries?
Differences are numerous. Engine was installed at a greater distance from firewall, so bigger guns can be installed in the fuselage, along with bigger ammo boxes for bigger ammo. The new position of egine also meant the wing need to be moved forward, so the CoG is 'undisturbed'. The wing can have fuel tanks installed, the type was not self-sealing though. The engine is two-stage supercharged DB 603L (no intercooler,fuel C3 only) or DB 603LA (has intercooler, can use B4 fuel). Armament package is exceptional on the 152C, four 20mm cannons and one big MK 103 cannon, the Fw 190C was to feature three 20 mm cannons and two MG 15 LMGs initially.
The main shirtcoming of the 152C is the weight and decreased G limit vs. the earlier FWs, and obviously the timing.

 

[EKB]

Why did this adaptation fail while the FW190D succeeded? My understanding was the 'kangaroo pouch' turbosupercharger had too many problems so they dropped it and moved on to the D and Ta-152. But why didn't they go for a supercharger like they did with the 190D? Also why didn't they go for a medium altitude FW190C without pouch? Could they have had a low/medium altitude fighter like the Hawker Typhoon in 1943 had they continued with a turbosupercharger-less Fw190C?

" It seems likely that the Fw 190C-1 series might have become a very effective high-altitude aircraft if the Hirth turbo-blower installation had proved satisfactory. It's failure can only be blamed on the desperate shortage of high-temperature steels, and was but one of many powerplant projects that broke down due to this cause.
The turbo-blowers themselves worked quite satisfactorily; failure occurred in the tubes used to conduct the exhaust gases from the engine to the turbo-blower assembly, the material used in their construction being unable to withstand the high temperature of the exhaust gases.
The whole installation was constructed at the Eberspraecher factory, using Sicromal 8, but in the first report on the equipment, issued to HMZ on May 23rd, 1944, they stated quite openly that the Sicromal was unable to stand up to the temperatures involved and that the exhaust tubes were damaged after as little as ten hours of operation.
Their second report, issued on October 26th, 1944, told the same sad story, this additional five months of development having only raised the operational life to some 20 hours. Altogether 81 turbo-blowers were installed, mostly of experimental construction ... Because of the lack of a suitable powerplant the decision was taken to end the development of the 'C' series ... The failure of the German aero-industry to produce a first-class high-performance engine was a continual and limiting factor to the performance of their aircraft during both the 1914-1918 and 1939-1945 wars."

See p.59
Nowarra, Heinz. The Focke-Wulf 190: A Famous German Fighter. Aero Publishers, 1965.

 

[rinkol]

Why did this adaptation fail while the FW190D succeeded? My understanding was the 'kangaroo pouch' turbosupercharger had too many problems so they dropped it and moved on to the D and Ta-152. But why didn't they go for a supercharger like they did with the 190D? Also why didn't they go for a medium altitude FW190C without pouch? Could they have had a low/medium altitude fighter like the Hawker Typhoon in 1943 had they continued with a turbosupercharger-less Fw190C?

I have a recollection that the reliability of the early versions of the DB 603 was so poor that the engine was considered only usable for twin engined aircraft, and even then, with reservations. The turbosupercharger would have added further problems as noted in the other posts. Aside from this, I suspect that the ME 410 and DO 217 had priority, in part due to preferences given to the production of offensive weapons. Nowarra's book on the DO 217 describes persistent problems affecting both the delivery and serviceability of DB 603 powered DO 217s. In some cases the DB engines were even removed and replaced by BMW 801s.

 

[Koopernic]

Although the DB603 entered service in mid 1943 (probably on the Me 410, possibly the Do 217) it did not break the 100 hour MTBO mark till 1944. This was a normal trajectory for a new engine in its first year of service. The DB603 was offered to the RLM, I believe as early as 1937, but was not accepted though Ernst Udet allowed a low priority development contract. The question will always be whether if the effort put into developing the Jumo 222 and DB604 had of been put directly into the Jumo 213 and DB603 whether the Luftwaffe would have had a 2000hp class engine earlier. Otto Marder at Junkers seemed to think so, saying that the Jumo 213 was a step that could not be skipped on the way to getting to Jumo 222 class engines.

 

[EKB]

Although the DB603 entered service in mid 1943 (probably on the Me 410, possibly the Do 217) it did not break the 100 hour MTBO mark till 1944. This was a normal trajectory for a new engine in its first year of servivce.

" On 8 June 1944, III./JG 300 was declared operational in defense of the Reich. For a period of four of five days our Gruppe carried out the final training flights in cooperation with the Messerschmitt 410 aircraft of Zerstörergeschwader 26. I felt sorry for their pilots as they seemed to suffer constant engine failures and even before we could form up into battle array, a good half of them had turned for home."

Arnulf Meyer
JG 300

See p.177
Jean-Yves Lorant Richard Goyat. JG 300 "Wilde Sau", Volume One. Eagle Editions Ltd, 2005.

 

[johnbr]

How about the db-624 in the fw-190c.

 

[SpicyJuan11]

Although the DB603 entered service in mid 1943 (probably on the Me 410, possibly the Do 217) it did not break the 100 hour MTBO mark till 1944. This was a normal trajectory for a new engine in its first year of service. The DB603 was offered to the RLM, I believe as early as 1937, but was not accepted though Ernst Udet allowed a low priority development contract. The question will always be whether if the effort put into developing the Jumo 222 and DB604 had of been put directly into the Jumo 213 and DB603 whether the Luftwaffe would have had a 2000hp class engine earlier. Otto Marder at Junkers seemed to think so, saying that the Jumo 213 was a step that could not be skipped on the way to getting to Jumo 222 class engines.

Could they have skipped to a de-rated Jumo 222? Or do you disagree with your previous statement?

Jumo 222 was never given a chance. It might have produced a viable 2000hp engine at the end of 1942 given that it was flying at the end of 1941.

 

[Koopernic]

Could they have skipped to a de-rated Jumo 222? Or do you disagree with your previous statement?

A 20% reduction in mechanical and thermal load is a considerable reduction in engine and bearing stress. It is also the initial design target. Having been able to use C3 fuel (about 95/125) rather than B4 ( mere 87 octane) also would have helped. The Jumo 222 was considered a viable engine for the Ta 152.

 

[wiking85]

A 20% reduction in mechanical and thermal load is a considerable reduction in engine and bearing stress. It is also the initial design target. Having been able to use C3 fuel (about 95/125) rather than B4 ( mere 87 octane) also would have helped. The Jumo 222 was considered a viable engine for the Ta 152.

Those two statements are at odds though, C3 fuel was only useful if you tune the engine to increased compression, which means a bigger bang and thermal load, plus stress on the engine parts, that would offset anything gained by slowing down the revolutions.

 

[tomo pauk]

C3 fuel does not require increase in compression ratio; increasing the CR is a self inflicted wound that, indeed, increases thermal load and stress on engine parts. The Jumo 222 restricted by 20% (from 2000 down to 1600) loses badly vs. BMW 801C, let alone vs. 801D, even vs. a fully rated DB 605A.
The 2-stage 801, Db 601/605 or Jumo 211 will provide far more for less.

 

[wiking85]

C3 fuel does not require increase in compression ratio; increasing the CR is a self inflicted wound that, indeed, increases thermal load and stress on engine parts. The Jumo 222 restricted by 20% (from 2000 down to 1600) loses badly vs. BMW 801C, let alone vs. 801D, even vs. a fully rated DB 605A.
The 2-stage 801, Db 601/605 or Jumo 211 will provide far more for less.

Isn't the entire point of high performance fuel that you can compress the fuel more before it detonates and drives the cylinder, allowing for greater energy transmission per revolution?

 

[dedalos]

C3 fuel does not require increase in compression ratio; increasing the CR is a self inflicted wound that, indeed, increases thermal load and stress on engine parts. The Jumo 222 restricted by 20% (from 2000 down to 1600) loses badly vs. BMW 801C, let alone vs. 801D, even vs. a fully rated DB 605A.
The 2-stage 801, Db 601/605 or Jumo 211 will provide far more for less.

Hi tomo,
i believe that by 20% derated jumo222., he means from 2500 ps down to 2000ps, not from 2000 to 1600 ps
And indeed ,in 1942, a 2000ps,1080 kgr jumo 222 would be extremely useful for the ju88 family, and the do217
However c3 is out of the question for a LW bomber. Even the Bmw s 801 when used on bombers had b4 fuel and reduced horsepower
I feel , of course i am just an amateur, the problems of the ju222 were more of political nature than technical
Kurt tank, in 1942, did propose the serial production of the Fw190C, in the form of the non turbosupercharged V13-V16 prototypes.
RLM rejected the proposal.Despite the problems of the db 603 in 1943, its quite reasonable to expect initial service for the Fw190C in september 1943 and full servise by early 1944. Of course that means cancel the me410.
But the main influence in RLM decisions was not of technical nature. The simply did not want ANY delay of production.They refused even improvements to the standart fighters , let alone introduce radical diferent subtypes. They kept producing obselete vertions of the 109 and 190 in order not to delay the production. Today we know the disastrous results of this policy. Not only the Fw190C was victim of this. The FW190D and Ta152A were almost ready for production in the spring1944 and still, the rlm delayed their production another 6 months.
My opinion is that the installation of the db 60A in the light Fw190A4 airframe with c3 fuel and an armament ofm 3 MG151s, would result in a formidable air superiority fighter until 8000m. With future use of the db603EM would be formidable until the very last day of the war.

 

[tomo pauk]

Isn't the entire point of high performance fuel that you can compress the fuel more before it detonates and drives the cylinder, allowing for greater energy transmission per revolution?

Nope, at least not in a supercharged engine tailored for reasonably high altitudes.
The point in having a high performance fuel is that the manifold pressure can be upped (without fear of detonation/pre-ignition that will quickly destroy the engine), and with it the greater power is produced by the engine. The power gain is almost in linear relationship with fuel performance number, while upping the compression ratio quickly gives diminishing returns. Among the engines with under 7:1 CR are not just major Allied types (Merlin, Hercules, V-1710, R-2800) but also German (Jumo 211, 213) and Soviet (Mikulin AM 38 and subsequent). Allison was reducing the CR of it's (way too) late models of the V-1710 from 6.65:1 down to 6:1 in order to be able to withstand greater boost, and heance to produce more power.
We can recall that AM 42 engine have had CR of 5.5:1, while managing more than 2 ata of manifold pressure on 95 oct fuel, without water-alcohol injection or intercooler.

2 ata is around +15 psig, 3 ata is around +28 psig:

 

[wiking85]

What's the difference between manifold pressure and compression ratio?

 

[tomo pauk]

Hi tomo,
i believe that by 20% derated jumo222., he means from 2500 ps down to 2000ps, not from 2000 to 1600 ps

Okay, roger that. However, reading about the 222 in the 'Flugmotoren und flugtriebwerke', pg. 90-92, that even the 2000 PS variant have had several problems, from rough running, corrosion, damaged impellers, problems with master slave rod arangement etc. Sure enough, the RLM request for 2500 PS version didn't helped out with situation.

And indeed ,in 1942, a 2000ps,1080 kgr jumo 222 would be extremely useful for the ju88 family, and the do217
However c3 is out of the question for a LW bomber. Even the Bmw s 801 when used on bombers had b4 fuel and reduced horsepower

For the Do-217, it would've probably, but for the Ju 88 it would probably take away much from bomb/fuel load?

I feel , of course i am just an amateur, the problems of the ju222 were more of political nature than technical

Both, methinks

Kurt tank, in 1942, did propose the serial production of the Fw190C, in the form of the non turbosupercharged V13-V16 prototypes.
RLM rejected the proposal.Despite the problems of the db 603 in 1943, its quite reasonable to expect initial service for the Fw190C in september 1943 and full servise by early 1944. Of course that means cancel the me410.

I'm the fan of the Fw 190C. So, yes, press on with it, even accepting problems with engine in all of 1943 (the BMW 801 have had that, so did the Sabre, they both eventually matured into useful engines), by 1944 those problems will be solved as realistically possible.

But the main influence in RLM decisions was not of technical nature. The simply did not want ANY delay of production.They refused even improvements to the standart fighters , let alone introduce radical diferent subtypes. They kept producing obselete vertions of the 109 and 190 in order not to delay the production. Today we know the disastrous results of this policy. Not only the Fw190C was victim of this. The FW190D and Ta152A were almost ready for production in the spring1944 and still, the rlm delayed their production another 6 months.

Let the Ju 188 have the BMW 801, so the Jumo 213A can find it's way on the Fw 190 (initially as an insurance vs. problems with DB 603), hopefully with 4 cannons and no fuselage MGs.

My opinion is that the installation of the db 60A in the light Fw190A4 airframe with c3 fuel and an armament ofm 3 MG151s, would result in a formidable air superiority fighter until 8000m. With future use of the db603EM would be formidable until the very last day of the war.

The C3 is not necessary with DB 603 on board. But I agree with other stuff you wrote

 

[tomo pauk]

What's the difference between manifold pressure and compression ratio?

Manifold pressure is measured in the intake manifold, and it is listed either in absolute terms (ata, in Hg, mm H2O, mm Hg) or in relative terms - ie. how much different vs. standard air pressure (eg. +12 psig, but also -2 psig, for example). Standard air pressure at sea level is 1 ata, or 29.90something in Hg, or +0 psig. Compressor helps when people wanted to increase manifold pressure, while water-alcohol injection and/or intercooler can help the compressor in that job. Different engines can accept different increase in manifold pressure before they fail, though.
Compression ratio is measured, or rather calculated in cylinder - didvide the volume in the cylinder when the piston is in the 'low point' with the volume in cylinder when the piston is in 'high point'. Merlin have had the CR of 6:1, most of V-1710s were at 6.65:1, DB 605A was at 7.5:1 for one cylinder bank, but 7.3:1 for another cylinder bank, the AM 38F was at 6:1, R-1830 was mostly at 6.7:1 etc.

 

[wiking85]

Manifold pressure is measured in the intake manifold, and it is listed either in absolute terms (ata, in Hg, mm H2O, mm Hg) or in relative terms - ie. how much different vs. standard air pressure (eg. +12 psig, but also -2 psig, for example). Standard air pressure at sea level is 1 ata, or 29.90something in Hg, or +0 psig. Compressor helps when people wanted to increase manifold pressure, while water-alcohol injection and/or intercooler can help the compressor in that job. Different engines can accept different increase in manifold pressure before they fail, though.
Compression ratio is measured, or rather calculated in cylinder - didvide the volume in the cylinder when the piston is in the 'low point' with the volume in cylinder when the piston is in 'high point'. Merlin have had the CR of 6:1, most of V-1710s were at 6.65:1, DB 605A was at 7.5:1 for one cylinder bank, but 7.3:1 for another cylinder bank, the AM 38F was at 6:1, R-1830 was mostly at 6.7:1 etc.

So that's how its measured, but what is the actual difference?