WWII MISTERIES: What happened with the JU390?

Soren raises a valid point that the Ju-390 was in response to an RLM specification for the so called Amerika bomber issued about 1942 and it was dated by 1945.

Better aircraft were available by 1944/45 including the He-177 with many engine overheating issues and the French built He-277. A conventional four engined version of the He-177

Soren you may have heard of the airport built near Oslo in the middle of a forrest called Gardermoen ?

At the end of the war 40 large bombers were found at the airfield in preparation for a mission to attack the United States. They were described as He-177 but may have included about 6 or 7 missing He-277. There is little accurate information available about Gardermoen, except that it had a very long purpose built runway for attacks on USA.

Re earlier Ju-390 posts, I can't recall the source at present but I understand the Ju-390 had a cruise around 240 knots. The maximum speed is often cited, but maximum speed is unhelpful.

Warbirds Resource Group refer to the Ju-390 with external bomb load at 267 knots cruise. The Ju-390 V1 coded RC+DA had a bomb aimer's gondola and appears to have been the maritime patrol bomber.

drgndog asked:

So either the specs as given are wrong, or the aircraft was an enormous hog and NEEDED that much hp just to get it to 20,000 feet.

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The wing loading is easily calculated from the Ju-390's wing area and MTOW, both of which are well known and documented with corroboration by the test pilot after the war.

The issue is limited engine performance at altitude. The B-29 for it's faults had massively supercharged air intakes optimised for high altitude.

And why is that? Did Leonard fumble his figures also? And what assumptions that you made are any more valid than his. So far this whole discussion including mine, are laced with 'assumptions' - said assumptions leaning to one side or the other in the debate - but assumptions nevertheless?

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I slightly rounded down the climb figures. The Ju-390 could undoubtedly reach 20,000 feet much faster than a B-29 with 18% more power, 55% lower wing loading and 85% better power to weight ratio than the B-29

You should note that even by including the slightly extra fuel for climb which you calculated the total fuel still does not exceed the Ju-390's known fuel capacity of 65,000lb.

On the other hand Richard Leonard's miscalculation is gross and excessive. He calculated fuel burn for the cruise at 500% more than was correct.

Thank goodness Richard Leonard is not a pilot, least I hope not.

The same is true of modern jet aircraft that you can optimise aircraft and engines for high or lower altitudes. The Rolls Royce Tay engine is built on the same core engine but has different versions with different fan sizes.

As an example the Fokker F-100 airliner used the Tay 650 engine with a wider Low pressure fan for shorter flights at lower altitudes has a service ceiling of just 35,000 feet.

The Gulfstream IV private jet designed to fly higher and for longer range uses the Tay 611 with a much narrower LP fan, but it can reach 45,000 feet service ceiling on basically the same engines with similar thrust and similar gross weights.



At Nationwide Air we flew ATL.98 Carvairs. They had astonishingly good fuel consumption. People who have never flown old radials just don't understand how much more fuel efficient a piston radial is over turboprops.

Kiwikid said:

The wing loading is easily calculated from the Ju-390's wing area and MTOW, both of which are well known and documented with corroboration by the test pilot after the war.

Yes if the data is correct, the wing loading is easily calculated

The issue is limited engine performance at altitude. The B-29 for it's faults had massively supercharged air intakes optimised for high altitude.

So you are willing to say that the BMW801E essentailly 'stopped' performing at 20,000 feet. the same engine used in the Fw 190A-9 and you believe this why? And did the personal account of a former test pilot have anything to say about this curious characterisic of an otherwise fine engine?

I slightly rounded down the climb figures. The Ju-390 could undoubtedly reach 20,000 feet much faster than a B-29 with 18% more power, 55% lower wing loading and 85% better power to weight ratio than the B-29

But you somehow find it plausible that the aircraft engines delivered 10,000+ plus hp, but failed to deliver enough to get past 20,000 feet?

Which set of figures do you believe - 10,000+ combined hp at some unspecified altitude, but not past 20,000 feet?

Or significant performance issues with the airframe design that was more than 6 robust engines could not compensate for lower wing loading despite 20+ more hp than a B-29

Or the data is wrong.

BTW if the BMW801E was failing to deliver its rated hp at 20,000 feet, where else was it 'short' and why would any data regarding performance be believeable? If the engines couldn't deliver the Hp at 20,000 feet, where did it fall off from design specs?


You should note that even by including the slightly extra fuel for climb which you calculated the total fuel still does not exceed the Ju-390's known fuel capacity of 65,000lb.

I did note that. Somehow I struggled my way through that to arrive at approximately 10,000 US gallons based on your suppositions. Now, having said that can you point to a surviving desing spec that states that 10,000 gallons were part of the design, or failing that a modification to create a 'tokyo tank' in the fuselage?

On the other hand Richard Leonard's miscalculation is gross and excessive. He calculated fuel burn for the cruise at 500% more than was correct.

.

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I honestly don't know who is correct. You haven't showed any engine performance data, no fuel consumption vs altitude or output horsepower

No cruise speeds as function of Gross weight for either max range or max endurance.

Why are you more believable if you can't produce optimal cruise speed and altitude?

I don't doubt your intelligence, or flight experience, but you are trying to suspend belief in this discussion by pointing to an alleged personal account which to this day has never been cooroborated by either surviving Junkers test data or another series of credible witnesses.

I am really agnostic on this subject but how in heck do you expect to prove your thesis? BTW your figures for 40-55 is about right for lowest cruise fuel consumption on a Packard Merlin 1750-7 at 48gal hour.

Is the same 'flawed' BMW801E that low on fuel consumption, and if it is what is the rated hrosepower and altitude for 40 gallons (or 55) gallons per hour.

Kiwikid,

The He-277 is like the He-177 a German built a/c made designed by the Heinkel Flugzeugwerke, the French had nothing to do with it.

As for the He-177 or He-277 attacking the US, well that would've been a one way trip seeing that max range was 6,000km.

If any bomber was going to bomb the US it would've been either the Me-264 with its 15,000 km range, or the Ju-390 with its 9,700 km range. (Would've been some VERY tiring missions though, flying for that long)

Bill,

The Ju-390 used the BMW-801D series engine, NOT the E series as in the FW-190 A-9. And the performance of the D-2 engine as we know fell off VERY sharply at high altitudes, hence the Ju-390's low ceiling.

This is pretty tiresome hairsplitting Drgndog. You yourself refer to the Mustang having hi fuel flow on take off and dropping to quite low fuel flow in cruise.

I'm quite well aware of that, but thanks for helping me further understand. The fuel flow from max power to optimal cruise varies quite a bit. For a P-51D the max is around 240 Gallons per hour and minimum cruise fuel consumtion was approx 48gph at 18K/1800rpm and 23" for a combat load

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Bit of an own goal don't you think ?

Kiwi - data from a single source, and a personal one at that, unmatched by other sources would lead me to at least hold belief in suspension. I'm glad you aren't a cynic like me

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A single source ?

Hans Joachim Pancherz and his wartime notes which are published only happen to be the single most authoritative source in the world on the Ju-390 and you say the aircraft's test pilot is not a good enough source.

You just seem to be arguing for the sake of arguing.

Or the data is wrong.

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Drawing a long bow based on nothing more than your conjecture.

BTW if the BMW801E was failing to deliver its rated hp at 20,000 feet, where else was it 'short' and why would any data regarding performance be believable? If the engines couldn't deliver the Hp at 20,000 feet, where did it fall off from design specs?

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More conjecture by you. Who said the BMW801 failed to deliver it's rated hp at 20,000ft ?

It was limited to that altitude and could not blow enough air into the cylinders above that altitude. It was a known fault of the engine. You're trying to build a thesis that the Ju-390 could not reach USA because you personally don't accept an aircraft with limited engine performance could fly that far.

May I remind you of the giant Dornier Do X which flew the Atlantic pre war never climbed much above 1500ft ?

the flying boats

So you are willing to say that the BMW801E essentailly 'stopped' performing at 20,000 feet. the same engine used in the Fw 190A-9 and you believe this why? And did the personal account of a former test pilot have anything to say about this curious characterisic of an otherwise fine engine?

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I wouldn't dare say it myself. Just to prove to you drgndog that this is not just what I say let me refer you to what others say about the BMW801 characteristics.

The BMW801 was well known for limitations at altitude because of it's engine driven superchargers. This was addressed late in the war with the BMW801G and that model's hydraulically driven 4 stage supercharger, but that engine was not fitted to the Ju-390 in early 1944.

BMW 801: Information and Much More from Answers.com

The supercharger was rather basic in the early models, using a single-stage two-speed design directly geared to the engine (unlike the DB 601's hydraulically-clutched version) which led to rather limited altitude performance, in keeping with its intended medium-altitude usage.

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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.

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The BMW 801 Radial Engine

The BMW 801 twin row radial engine formed the basis of the Focke Wulf fw190 design. This engine has the reputation as being among the better engine designs of WW2 regardless of limitations in German supercharger technology which lead to some failings at high altitude.

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I don't know some of the facts you demand answers to. The warbirds resource group is the only reference point which i can point to from off my head that refers to a cruise speed as opposed to maximum speed for the Ju-390 and that was 267 knots which i find a bit excessive.

The DC-4/Carvair cruised about 220 knots. I recall reading somewhere that the Ju-390 cruised at 240 knots but can't give you the source.

I expect the Ju-290's cruise was similar to a Ju-290's so that may be a starting point for investigation.

I'm not trying to close down debate Drgndog. If Rich's claim were subjected to the same scrutiny it would be obvious that he overestimated the fuel consumption.

Take some equivalent aircraft like the DC-4 and look at their fuel consumptions because you'll find the same applies.

The He-277 is like the He-177 a German built a/c made designed by the Heinkel Flugzeugwerke, the French had nothing to do with it.

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Hiya Soren, I can't quote a source at the moment but before the invasion of france He-177 airframes were sent to a French aircraft manufacturer and had the wings modified for a conventional 4 engine installation.

I stand to be corrected but I am pretty confident that I have read an authoritative source on this. No arguments that it was the best German bomber.

Had Ernst Udet not persuaded Goering to drop the 1936 specification for a Urals bomber after Webel's death and instead focus on tactical dive bombers like the Do-17 and Ju-87, Germany would have had a fleet of strategic bombers in 1939.

I have read that the Ju-390 was originally fitted with the BMW 801D and at some point later was fitted with the BMW 801E, but the altitude issues were not fully solved until the BMW 801G and BMW 801R.

I have no idea which engine type was fitted in January 1944 and you may well be correct Soren.

My fuel calculations and comparison with the B-29 incidentally were based on the BMW 801D of 1730hp per engine.

The He-277 is completely German Kiwikid, designed in Germany by the Heinkel design team as a further development of the He-177. The aircraft itself was built in Austria.

Regarding any French involvement you must be remembering wrong Kiwikid, cause the French didn't get a hold of any He-177, and by the time the invasion was over the French completely ceased designing a/c. The He-177 first entered service in 1942. Another a/c, the He-274, was however built by Heinkel in France, but the design was completely German, the labor being only thing French. It was simply a case of the Germans utilizing captured production facilities instead of spending funds on building them themselves.

As for the Ju-390, it was powered exclusively by BMW-801 D-2 engines.

The French Air Force had one He 177 - after the war.

Kiwikid said:

This is pretty tiresome hairsplitting Drgndog. You yourself refer to the Mustang having hi fuel flow on take off and dropping to quite low fuel flow in cruise.

Yes I did. I gave them to you in the conditions and altitudes and rpms and boost for a very efficent in line engine which has 15-20% less hp than the 801E. You have given me zero in return for a very large and powerful radial engine

You said the following to start this discussion


Now that you've read Richard Leonard's figures... here's the true figures:

The Ju-390 used six BMW 801E engines which were identical to the BMW 801D except the E version was geared for better performance at altitude. The 801E was geared for lower engine revolutions.

Nice statement, rich in promise..

In all other regards one can consider fuel consumption the same or slightly superior fuel consumption for the 801E. The E version had about a 100hp superiority at altitude.

But where is the 'beef' - Nice assumption, no facts

The BMW 801E also had a boost function for take off, by injection of a water methanol mixture into the left supercharger inlet. This could only be used for 10-15 minutes. Only at these boost settings does the fuel consumption rise to 221 US Gals PH.

So, at what altitudes do the BMW 801E operate most efficiently? and at what boost settings, rpm and fuel flow - for the Ju 390 V2 - to either obtain maximum range or maximum endurance. As a pilot you will know those are usually two different settings, (and altitudes and cruise speeds)

A single source ?

Hans Joachim Pancherz and his wartime notes which are published only happen to be the single most authoritative source in the world on the Ju-390 and you say the aircraft's test pilot is not a good enough source.

You just seem to be arguing for the sake of arguing.

I'm arguing because you haven't produced the above detail that would make it possible to verify either endurance or range. Apparently neither has the test pilot? This story has been around a long time w/o corroboration.

Drawing a long bow based on nothing more than your conjecture.

Skepticism based on many claims, vague assumptions and few facts,

More conjecture by you. Who said the BMW801 failed to deliver it's rated hp at 20,000ft ?

Actually - Soren did, then you.

This illustrates the above skepticism.

Actually I find it extremely hard to believe that a 801E 'dies' at 20,000 ft. Soren just stated that the E had 'well known' altitude problems but I hadn't heard that. Hell, that engine was designed to go into Fw 190s as well as other applications - so No I don't believe this

But when performance data of a 'marvelous' aircraft with nearly 50% more horsepower than a B-29, has a wing loading 10% less than a B-29, (according to all the sketchy references available so far) BUT ONLY HAS A SERVICE CEILING of 20,000 feet - well below a B-29 - doesn't that give YOU pause that something is fishy??


You're trying to build a thesis that the Ju-390 could not reach USA because you personally don't accept an aircraft with limited engine performance could fly that far.

Well, No. I'm building a thesis that either the aircraft was very dirty aerodynamically if it couldn't go past 20,000 feet with six very powerful engines, or

The published ceiling data is wrong (and what else is wrong), or

The published engine for the aircraft is wrong, or

The engines actually failed altogether with second stage boost and ceiling WAS severely limited - I'll check your references for the latter... but if true the V1 with BMW801D should speculatively cruise farther than a V2

May I remind you of the giant Dornier Do X which flew the Atlantic pre war never climbed much above 1500ft ?

Ah, no. The Panama Clippers did not fly very high of very fast either

the flying boats



I wouldn't dare say it myself. Just to prove to you drgndog that this is not just what I say let me refer you to what others say about the BMW801 characteristics.

The BMW801 was well known for limitations at altitude because of it's engine driven superchargers. This was addressed late in the war with the BMW801G and that model's hydraulically driven 4 stage supercharger, but that engine was not fitted to the Ju-390 in early 1944.

BMW 801: Information and Much More from Answers.com





The BMW 801 Radial Engine



I don't know some of the facts you demand answers to. The warbirds resource group is the only reference point which i can point to from off my head that refers to a cruise speed as opposed to maximum speed for the Ju-390 and that was 267 knots which i find a bit excessive.

Actually, the other resources show the Max speed with external weapons as 267 mph. That is a far cry from optimal cruise speed either for range or for endurance.

The DC-4/Carvair cruised about 220 knots. I recall reading somewhere that the Ju-390 cruised at 240 knots but can't give you the source.

IF true, that would represent a range close to 7500 miles. Is that your thesis? A very clean, no bomb load B-29 was capable of 5400 miles ferry - similar to a Recce -

I expect the Ju-290's cruise was similar to a Ju-290's so that may be a starting point for investigation.

The Ju 290 with four engines should be cleaner. Having said that with the four BMW801G, it seemed to also have a 6000m ceiling



I'm not trying to close down debate Drgndog. If Rich's claim were subjected to the same scrutiny it would be obvious that he overestimated the fuel consumption.


I have no problem with this statement. On the other hand we have yet to establish any solid data for the Ju 390.

Take some equivalent aircraft like the DC-4 and look at their fuel consumptions because you'll find the same applies.

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If we go to trying extrapolate the performance against the DC-4, we have to establish the baseline for Both ships to determine actual reasonableness

1. Either the Test Cruise curves for altitude, sfc, rpm, boost, TAS as a function of payload, or

2. Published data for optimal cruise speed for a.) endurance or b.) range

But as a pilot you know that you need far more than fuel consuption data for the engine - you have to know how the aircraft as a SYSTEM performs with respect to engine, payload, aerodynamics and altitude.

Listen are you guys interested about knowing the truth or do you just want to argue ??

For the last time the Ju-390 was equipped with the BMW-801 D-2 series NOT the E series!

And here's the power curve of the BMW-801D2, as you can see performance decreases rapidly at high alt:

Compare the above to the power available to the B29 at that altitude and you'll quickly realize why there was such a big difference in service ceiling.

Soren said:

Listen are you guys interested about knowing the truth or do you just want to argue ??

Interesting question Soren - what is the 'truth' - your truth or the sketchy details provided by other equally vague sources?

uboat.net - Technical pages - Junkers Ju 290 and Ju 390

The Ju-390
Two prototypes flew of a radically modified derivative, the Ju 390. The idea behind this was simple: The wing center section panels, complete with engines and landing gear, where fitted twice. The fuselage was elongated. In this was the four-engine Ju 290 was modified into the six-engine Ju 390. The Ju 390V1 was equipped as as a transport aircraft, and the Ju 390V2 as a long-distance maritime patrol aircraft.
They flew in August and October of 1943. The V2 was delivered to FAGr.5, and it demonstrated its potential by flying from Mont-de-Marsan to a point 20km from New York, and back. [Editor: many believe this is a rumor and that the flight was never undertaken]



Specifications
Junkers Ju 290A-5
Nine-seat long-distance reconnaissance aircraft

Four 1700hp BMW 801D radial engines Wing span 42.00m, length 28.64m, height 6.83m, wing area 203.6m2. Maximal take-off weight 44970kg. Max. speed 440km/h at 5800m, cruising speed 360km/h. Service ceiling 6000m Range 6150km

Armament: Two dorsal turrets, each with a 15mm MG151, one MG151 in the tail, two in beam windows, and one in the front of the under nose gondola. One 13mm MG131 in the aft section of the gondola.



Specifications
Junkers Ju 390V2

Six 1970hp BMW 801E radial engines Wing span 50.32m, length 33.6m Empty weight 36900kg, max. take-off weight 53112kg Max. speed 515km/h at 6200m, cruising speed 357km/h. Max. range 9700km.

Armament: Two dorsal gun turrets, each with a MG151, and one MG 151 in the tail. Aft and front MG131s in the gondola, and two MG131 beam guns.


For the last time the Ju-390 was equipped with the BMW-801 D-2 series NOT the E series!

And here's the power curve of the BMW-801D2, as you can see performance decreases rapidly at high alt:

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And yet another 'truth' to lay on top of so many 'truths' on this subject

http://www.warbirdsresourcegroup.org/LRG/ju390.html

Type: Long Range Bomber or Reconnaissance aircraft.
Origin: Junkers Flugzeug und Motorenwerke AG
Models: V1 to V3 and A-1
Crew: N/A
First Flight: Prototypes only
Final Delivery: None
Number Produced: V1 and V2 Only

--------------------------------------------------------------------------------
Engine:
Model: BMW 801E
Type: 18-Cylinder two-row radial
Number: Six Horsepower: 1,970 hp

--------------------------------------------------------------------------------
Dimensions:
Wing span: 165 ft. 1 in. (50.30m)
Length: 112 ft. 2.5 in. (34.20m)
Height: 22 ft. 7 in. (6.89m)
Wing Surface Area: N/A

Weights:
Empty: 81,350 lb. (36,900 kg)
Loaded: 166,448 lb. (75,500 kg)
Performance:
Maximum Speed:
Clean: 314 mph (505 kph)
With Max. Eternal Weapons: 267 mph (430 kph)
Initial Climb: N/A
Service Ceiling (Typical): N/A
Range in Recce configuration:
6,027 miles (9700 km)
Endurance in Recce configuration: 32 Hours

--------------------------------------------------------------------------------
Armament:
Eight 20mm MG 151.
Eight 13mm MG 131.

Payload:
Transport (V1): 22,046 lb. (10,000 kg)
Bomber (V3): 3,968 lb. (1800 kg)

Avionics:
FuG 200 Hohentwiel Radar.

So, once again - what are the facts? what is the truth?

Where will anybody get a clue regarding the Ju 390V1 or V2 with respect to facts.

I'm willing to believe any performance figures based on either well founded calculations based on exhaustive wind tunnel results with at least one test flight to reference areas of agreement versus differences from the theoretical.

None of those factors are present here. Period.

Now - what is YOUR source for BMW810D for the Ju 390(either V1 or V2) so that Kiwi and I shall know the 'truth'? What is your source for bomb bay existence vs wing racks?

What is the source for internal fuel of 65,000 pounds? If true, were there special mod for Recce Version to get the loiter? What was the cruise speed to attain 32 hours endurance? what was the cruise speed to get 6000-6200 miles of range? was the range an actual or a theretical? what would a flight profile and loading look like to a.) make a 32 hour Recce, b.) fly 6200 miles with a bomb load - or no bomb load? or what?

You believe a Truth but you don't have any of this to demonstrate you have an assembly of relevant facts? Nor does Kiwi.

I got involved because I saw an analysis that seemed reasonable to me based on the numbers presented. I got into this in more detail when Kiwi posed that nobody knew what they were talking about and proceeded to a.) get the math wrong by nearly 20% on his own figures and assumptions - much less any assumptions based on a referencable source that applied to the case in question.

I AM NOT an expert on the Ju 390 but I damn sure know how to plan an IFR flight plan at the outer range of my airplane's limits - you should also as well as Kiwi - but I didn't see either of you asking fundamental questions to test or demonstrate your own belief.

Now - just suppose that the BMW801 E WAS used on the Ju 390 - what are the performance figures for that? Then Soren we have one leg of the analysis that you and I could do together.

After that we need to know how much actual fuel could be loaded onto this beast and safely take off.

After that we would like to know where the best altitude and speed is for a.) minimum fuel consumption, and b.) best altitude and cruise speed for best cruise mile per gallon consumed.

Then we could figure out what mission we want - Recce with no payload, Recce with payload, Ferry with no payload, Bomb mission at max range and the payload which could be carried to max range.

If then, the payload must draw from fuel (if max fuel - max gross weight), then we have another set of condition for range.

etc, etc.

So, where do you suggest we get facts for a mission profile?

The V1 V2 were equipped with the D-2 engines, the A-1 was supposedly to be equipped with the E engine.

Junkers Aircraft of WWII

Now since you're not aware of it, the E engine was no better at high alt than the D-2 engine, the extra power only giving the FW-190 A-9 a service ceiling some 200m higher than that of the D-2 powered A-8.

From German Leistung charts:
FW-190A-8, service ceiling: 10.6 km
FW-190A-9, service ceiling: 10.8 km

Wow! What an improvement!

Now if you still don't understand that the BMW-801 was the reason for the lower ceiling then I must say you've lost your touch in this area quite abit Bill.

No Soren it is not

He is only asking what everyone else asks for and that is a source...

did the 390 actually fly for 32 hours or is that a should number

DerAdlerIstGelandet said:

No Soren it is not

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I just dislike the suspicious tone, that's all...

He is only asking what everyone else asks for and that is a source...

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Which he has now recieved.

Soren said:

I just dislike the suspicious tone, that's all...

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It only mirrors yours...

I don't recall being suspicious about anything like this.

It's a quite simple and well known fact that the BMW-801 didn't perform well at high altitude, the FW-190A suffered from this throughout its service life. So that the Ju-390, which is powered by BMW-801 engines, has a low ceiling is a no brainer really. However despite this Bill somehow comes to conclusion that the airframe was draggy

Soren said:

The V1 V2 were equipped with the D-2 engines, the A-1 was supposedly to be equipped with the E engine.

Junkers Aircraft of WWII

Soren - two points. I found no reference to Ju 390V1 or Ju 390V2, nor BMW801D-2 engines for any version (specifically) in your link.

Second point, the link you provide references in its Technical Data table a Ju 390 (no V1, V2, A1 or A2 - just "Ju 390") with two engine configurations, namely 8x 801D or 6x 801E. Which do you prefer since only one Ju 390 was built and flown?

Below the Technical Table in your link is the last reference to the Ju 390 finally referencing a Model number - but not the V1 and V2 you referenced in your above statement.

"Ju390A1 transporter aircraft with 6 x BMW801E, one built in 1943, second not completed. "

So - what is the Model Number you propose for the Ju 390 or since only one flew and is the alleged New York Bomber shal we just refer to it as THE Ju 390?

And last - since the photos I look at seem to have only six engines and the Tables you linked to describe "6 x 801E", may we refer to 801E instead of 801D-2 from now on?

Is my request OK so far?

Now since you're not aware of it, the E engine was no better at high alt than the D-2 engine, the extra power only giving the FW-190 A-9 a service ceiling some 200m higher than that of the D-2 powered A-8.

From German Leistung charts:
FW-190A-8, service ceiling: 10.6 km
FW-190A-9, service ceiling: 10.8 km

Wow! What an improvement!


Observation - you stated earlier that the BMW 801E had well know altitude issues when I 'wondered' why a B-29, with greater WL and far less horsepower than a Ju390 - still had a service ceiling (with a 20,000 pound bomb load) 14,000+ ft higher than a Ju 390. Then you just make a statement that the 801E improved the ceiling of the Fw 190A-9 to 10.8 Km?

Question - you have a reason that an engine (BMW801E) that only increased service ceiling to 10.8 Km on an Fw 190A-9 was somehow deficient in enabling the Ju 390 to beyond 6 Km service ceiling? Where did the 801E encounter the 'high altitude' problems you alluded to at the 6Km mark?

Now if you still don't understand that the BMW-801 was the reason for the lower ceiling then I must say you've lost your touch in this area quite abit Bill.

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Well, obviously you have confused me Soren. You said the BMW 801E had well known altitude problems but you point out it still enabled a higher service ceiling for the Fw 190A-9, over the service ceiling of the Fw 190A-9 with the 801D. What did I miss? Did it run into it's "well known altitude problems" with the Ju 390 at 6 Km, but somehow struggle up to 10.8Km with the Fw 190A-9.

You are an aerodynamicist, correct?

Then what is your explanation for this paradox of an alleged aircraft that has a lower wing loading, much higher base Hp with Six BMW 801E engines, but can only climb to 6 Km - when a slug of an aircraft like a B-29 with a 10% higher wing loading and 40% less power can climb to 10Km with a 20,000 pound bomb load.?

It must be clear that I have lost my touch in this area quite a bit Soren.. could you please help me find the way back to reality?

The FW190A-9 is a fighter for crying out loud, and its power-loading is significantly lower than that of the Ju-390, as-well wing loading, hence the higher ceiling.

Also the increased horsepower provided by the E series over the D-2 series only increased the ceiling of the FW-190 a mere 200m! Therefore there'd be no difference between a Ju-390 equipped with D-2 engines and one equipped with E series engines! Is that so hard to understand ???

Furthermore the V1 was the only one to ever fly, and it was equipped with the D-2 series engine. The A-1 was the version which was to have the E series engine, but IT NEVER FLEW!

Finally the B-29 featured four 2,200 HP turbo-supercharged engines, with excellent high alt performance, hence the higher ceiling!

If you still don't understand that the BMW-801 engines were the reason behind the Ju-390's low ceiling, then yes, you have lost your touch.