WWII MISTERIES: What happened with the JU390? (1 Viewer)

[drgondog]

Misquoting Soren

Now you're misquoting Soren to wad your argument. Actually Soren does not agree with you. That's yet another example of intellectual dishonesty. You are well aware that Soren believes the Ju-390 could exceed 20,000ft.

You are equally aware that you do not believe the Ju-390 could exceed 20,000ft.

Kiwi - you have a serious reading comprehension problem - Here is what Soren said when I commented that I was having a hard time believing that the service ceiling was only 6,000 M

"The high AR of the B-29's wing will increase lift whilst decreasing the drag, increasing the L/D ratio, a great advantage. I haven't looked into the difference in AR though, but even small differences have very noticable effects.

I too believe that the service ceiling of the Ju-390 was higher than 6 km, probably 8-9 km, but no more as the BMW-801 lost performance rapidly above 20,000 ft. "

Kiwi sez-"To say that Soren agrees with you is to distort the truth. If that is the lengths you're prepared to go to, then it is an act in futility debating with you , because the debate can't proceed on a rational basis".

Wiki - You have to be either 'rational, or able to read and faithfully regurgitate what you comprehend for this debate to make sense. Go look at the series of discussions between Soren and my self starting with this comment



Originally Posted by Soren
Soren sez -"Btw, the figures from U-boat.net are interesting, noting a top speed of 515 km/h at 6,200m. Now top speed is never anywhere close to the service ceiling so somehing aint right.

Sources are very different on this bird..."

Kiwi - What do you make of this?

Refusing to read evidence

Kiwi sez-"I provided you with facts from NACA testing of the BMW-801 engine. It seems to me that you're reacting in a huff because you don't want to address those facts. Are you refusing to read the NACA report before mouthing off against it ?"

Kiwi - have you gone back and noticed that a.) I'm not reacting in a huff 'because I don't want to address those facts' - simply because I wasn't the one to 'mouth off against ANY NACA report!! You keep confusing my statements with someone else. Actually I don't mind defending myself against you but you seem to want all offensive statements (to you) laid at my feet!

Kiwi sez- "The engine performance chart published earlier at your post #93 is for rpm settings which change gear in the supercharger and change the engine from lean fuel to rich fuel.

SOREN posted 93 Kiwi!!!!! as he did many you attribute to me!

" 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."


Do you comprehend the d i f f e r e n c e between SOREN and DRGONDOG?

Kiwi sez - "The engine performance charts in the NACA report clearly show a jump in fuel consumption above 2150 rpm and above 20,000ft.

Glad to hear this, and your point is?

Kiwi sez-"Much earlier in this thread you asked me if I knew the optimum cruise altitude for the Ju-390. The NACA tests disclose the BMW-801 had a sweet spot from 14,000ft to just above 20,000ft where the performance and fuel consumption was steady at 17000rpm and 27 inches boost.

I think you have a problem with either 'the math' or 'reading comprehension' again. The Rpms sound like a dentist's drill - not a BMW 80. As for the AIRPLANE/ENGINE SYSTEM, what was the "sweetspot" for the Ju 390?

So now you are ready to deliver a chart which reflects either manufacturer's specs for cruise for the Ju 390 or flight tests and will state the payload, the altitude, the specific fuel consumption? Great - we have ALL been looking for that.

Kiwi sez -"I have earlier given you a source for reading test pilot Hans Pancherz's own notes and charts for the Ju-390. I see that you've made no effort to read those either."

You are drawing from memory - it hasn't been great. You have drawn from 'reading Pancherz's notes' - but there is no evidence of notes. You are basing your entire claim of NY trip based on his notes - but there is only his word. He bases his notes and his data on what? Nobody is quoting Junkers! I don't have access to the book. You apparently don't either. Does anybody think it is a good idea to have a fact based discussion? where are the FACTS.

Kiwi sez "Instead you're mouthing off that everyone else in the world is wrong except you

Nah


Kiwi sez -Repeating a false statement

I did not get the maths wrong. As explained, I rounded down the time to climb. You are engaging in misrepresentation. That is intellectual dishonesty. You've been told the facts. You keep denying them.

Here is specifically how you performed the math and BTW introduced the BMW 801E into the discussion

Kiwi sez- "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.

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.

The B-29 which had 80% higher wing loading and less power, took 25 minutes to reach 20,000ft. Actually at 120,000 pounds the B-29 has a wing loading of ~ 69 and at Max Gross TO of 133,000, ~ 76.

The Ju 390 according to 117,092 and 166,400 have ~43 and ~66. Where do you find an 80% difference? Is it the math?

So run six engines at boost for 15 minutes is 331.5 US gallons (1989lb)

Normal max operating consumption is 90-103 US Gal per hour per engine so let's keep climbing for another 10 minutes at 90 US Gal/engine...(54lb)

Okay so to reach 20,000ft the Ju-390 needed 25 minutes roughly and about 2043lb of fuel.

OK Kiwi - the above is what you said and the math you performed

I see 221x 6 engines for .5 hr + 331.5 gallons x 6.5 pound/gal = 2154.. plus 90x 6 x 1/6 hr x 6.5 = 585 pound

= 2739 pounds and 421 gallons

Call me crazy and opinionated about your 'math". Does the difference between your calc with your assumptions yielding 2043lbs versus 2739lbs look like a round off error to you? Explain your definition of "round off".. anything less than say 25% Ok with you?
QUOTE]

Kiwi - we can argue the weight of gasoline based on additives as being between 6.1 and 6.5 pounds per gallon, we can argue that the weight of cool gasoline is greater than 'warm'' but can we argue 90 gallons per hour x 1/6 hour (10 min) x 6 engines/@221 gal/hr is NOT 54 pounds ?

Is my statement 'false' or did you screw up the math?

 

[drgondog]

Do you even know what point you are trying to make?[/B]

That's odd because both Richard Leonard and yourself have extensively posted what you appear to term proof that "there is no proof that the Ju 390 flew to NY and back"

Conversely - You have demonstrated that it did? - one of us is wrong!

Actually, no. What Rich questions raised, and I amplified in my own discussions, is that far too much is believed by too many people without any tangible proof of the event?"

When others have posted more accurate information you've either:

(A) attacked them
(B) attacked their information.

Actually NO again. I have questioned both your and Soren's Statements of facts not in evidence and the sources for the facts - neither of which are in abundance from you.

I pointed out to Soren that what is available on the web is largely contradictory with respect to even the version types and quantity built, much less the engines used, the quoted ceilings for an aircraft with perhaps 33% more power at SL than the corresponding B-29, with a lower wing loading than the same loaded B-29.. I think he and I are in some agreement that FACTs are hard to come by on this bird.

To date you have

a.) presented your arguments based on 'Belief system' that the notes and data presented by a former pilot of the Ju390 are accurate and reflect the 'facts' of the aircraft's performance and it's flight to NY.

b.) have no other flight test, design specifications by Junker, actual 'as built' configuration for the Ju 390 or any usually reliable reports from say the LW to corroborate your belief systems.

c.) no clue what the operating performance envelope is for the aircraft, what its' mission configuration was for the 'Ny Flight', no idea concering the actual specified cruise settings for the BMW801E (or D if it was used) in the Ju 390 for either max range or max endurance.

d.) no clue what the alleged fuel load, version type (passenger, recce, bomber) was for the 'trip'. Somehow for the mission, believe there was enough remaining load capacity to carry another 10,000 pounds as a bombload? And hang it where? and still fly for 32 hours?

e.) made many assumptions about the cruise and take off/climb fuel consumption rates when you have no data to support them (we still aren't sure which 801 engine was used) - and base them on your pilot 'credentials'?

f.) blown away Rich's analysis based on your own unfounded assumptions and poor math.. and ready to tell him the 'Real story"

But you question my skepticism (and Rich's) of those that present "better information"??

When are you going to get around to asking questions a 'real pilot' would ask if someone said 'Take this Ju 390 to New York - bring it back if you can?"

There are a LOT of 'real pilots' on this forum that would ask the same questions I have to just get to the point where
a.) I decide it is a credible accomplishment based on the facts, or
b.) I decide it is patent BS because there are no facts (much less 'plenty, but not enough') to support a conclusion.

To summarize'

Your math was bad - deal with it.
Your flight profile assumptions have no substance, no data and no credibility
Your 'belief system' is credible relative to the Ju 390 pilot - entered into evidence - but still not a verified fact!
You don't like me when I ask you tough questions about Real Flight Performance data necessary to generate analysis.
You didn't 'like' others questioning your flawless logic or 'information'.
You frequently confuse statements made by me with statements made by others!

And you accuse me of not being objective? Did I hurt your feelings? I am sorry about that.

 

[Soren]

The B-29 did not have a 80% higher wing-loading than the Ju-390, that's for sure. The difference in wing-loading was closer to 60%, which is still allot, BUT here's what I know:

The Ju-390 either used the BMW-801D or E engine, both were at a disadvantage at high altitudes, power decreasing rapidly above 22 - 23,000 ft. So although I do believe/know that the Ju-390's service ceiling was higher than 6km, it couldn't have been much higher than 8 to 9 km seeing that the performance of the BMW-801D E engines completely evaporated at those altitudes.

As for the B-29, well alone because that its engines are fitted with turbo-superchargers it's no surprise that its ceiling was higher. Furthermore the B-29 benefitted from a more efficient wing, the higher AR increasing lift whilst decreasing drag, raising the L/D ratio.

Here's the effect AR has on the lift drag of an a/c and thus the L/D ratio:

With similar CLmax figures let me demonstrate just how important wing AR is;

L/D ratio = Cl / Cd

Cd = Cd0 + Cdi

Cd0 = {Negligable as it always lies in the 0.02 -0.025 area}

Cdi = (Cl^2)/(pi*AR*e)

So for the comparison we assume a Clmax of 1.3 for both and Cd0 of 0.02 for both, now note the difference wing AR alone has on the L/D ratio (one of the most crucial factors to high turn performance), and the higher the L/D ratio the more efficient the wing is.

Wing with AR of 8

(1.3^2)/(pi*8*.85) = 0.0791093688

0.0791093688 + 0.02

Cd = 0.0991093688

1.3 / 0.0991093688 = 13.1168225

L/D ratio = 13.11

Wing with AR of 6

(1.3^2)/(pi*6*.85) = 0.105479158

0.105479158 + 0.02

Cd = 0.125479158

1.3 / 0.125479158 = 10.3602863

L/D ratio = 10.36
_______________________________

L/D ratio Differential: 35.9 %

Additionally two graphs showing the difference in L/Dmax between a wing with an AR of 4 vs a wing with an AR of 9:

AR 4

AR 9

Now the B-29's wing was of a very high AR, 11.53 infact, which meant it was a very efficient wing with a very high L/D ratio, something which was also needed if the B-29 was to be a good performer at altitude.

The Ju-390's wing was of 9.96, also high but still lower than the B-29's by 1.47, which is noticable in lift drag.

In short, the higher ceiling of the B-29 can attributed to its turbo-supercharged engines and more efficient wing. The Ju-390 no doubt could've gone higher than the B-29 had it had turbo-supercharged engines, however it didn't.

 

[drgondog]

Kiwi sez- "Well that's a very interesting assertion (that no Mustang was flown by Germans prior to 6 June 1944. Try this autobiographical account from Walther Dahl about a captured Mustang being flown by Zirkus Rosarius in 1943 complete with pictures.



Kiwi sez -"Walther Dahl flys the P-5During 1943 Hptm. 'Ted' Rosarius was tasked with forming a Versuchsstaffel of captured enemy aircraft that would serve to familiarise pilots of the Reichsverteidigung (German air defence) with the strengths and weaknesses of Allied fighter aircraft. Designated 2./Versuchsverband Ob.d.L and dubbed the Zirkus the unit demonstrated the latest captured Allied fighters in mock combat programmes that were an important aid during a period when German fighter pilot training programmes were under increasing pressure....the following is extracted from Walther Dahl's memoir and describes a visit by the Zirkus to JG 300..."

Kiwi - do you get tired of setting yourself up? Here is the article in its entirety!!!! from Dahl's writings as quoted by YOU in the above link!

{{Bill Note: MEMO TO KIWI - Dahl left IV./JG3 in May 1944 to organize and lead SturmGruppen in JG300}}

Now Kiwi - since you wish to use this as proof that Dahl flew the Mustang in 1943, let us read it one more time. There will be a quiz at the end!

Dahl recounts - "...despite the successes we had enjoyed over the course of our recent sorties, a number of gaps had started to appear in our ranks. Seasoned Staffelkapitäne, experienced Schwarmführer, Leutnante, Feldwebeln and Unteroffiziere - pilots who were the backbone of our unit - had all been posted missing in action . Men such as Oblt. Hirschfeld of 6./JG 300 who was lost in combat on 28 July 1944 and posthumously awarded the Knight's Cross.

{{Bill Note: MEMO TO KIWI - My father led the fighter escort for the 355th FG on this day and Lt James McElroy 358FS/355FG was the pilot that killed Hirschfeld and his wingman! The date, July 28, 1944 is correct and he was shot down in the Erfurt area}}


Dahl continues - " There were plenty of new young replacements, all volunteering to fly with the Sturmgruppe but virtually none with any front-line experience. Despite the constraints on time, fuel and aircraft availability, it was down to us to complete the training of these youngsters, to " fly them in " under operational conditions as it were. Fortunately our great fears of an on-going all-out offensive by the American bomber formations proved groundless. They had more than enough on their hands in Normandy. We flew few combat sorties during this period. A spell of bad weather also set in.

{{Bill Note:MEMO TO KIWI- does the above phrasing give you a clue that the time was after Normandy?? Were you aware of Dahl's command experience in being with IV./JG3 in April/May 1944 before he went to JG300?}}

Dahl further states - "..it was during this period of enforced inactivity on a gray overcast day that the "Zirkus" flew into Wörishofen. Evidently this was not the kind of circus that featured exotic animals and other attractions; the 'star performers ' here were a collection of captured enemy aircraft displayed by a Sonderkommando under Major Rosarius tasked with touring the bases of those units deployed in the west against the bomber formations. Formation leaders (Verbandsführer) were given the possibility of flying these machines in mock combat and thus becoming more closely acquainted with their characteristics, a factor that was not to be under-estimated in air combat with our opponents. Following this session, flight leaders would hold a series of training lectures with their men and were able to pass on recommendations from their own observations and experience at the controls of these aircraft. This was why one morning enemy fighters such as P-51s, P-47s, Lightnings along with the heavy bomber types, could be seen peacefully arrayed alongside our own machines, when their appearance over the field would normally have provoked anything but a friendly reaction.. ."

Mustang T9+CK was being tested at Rechlin long before the Normandy landings.

And your source for this is?

 

[drgondog]

Misquoting Soren

Now you're misquoting Soren to wad your argument. Actually Soren does not agree with you. That's yet another example of intellectual dishonesty. You are well aware that Soren believes the Ju-390 could exceed 20,000ft.

You are equally aware that you do not believe the Ju-390 could exceed 20,000ft.

Kiwi - you have a serious reading comprehension problem - Here is what Soren said when I commented that I was having a hard time believing that the service ceiling was only 6,000 M

"The high AR of the B-29's wing will increase lift whilst decreasing the drag, increasing the L/D ratio, a great advantage. I haven't looked into the difference in AR though, but even small differences have very noticable effects.

I too believe that the service ceiling of the Ju-390 was higher than 6 km, probably 8-9 km, but no more as the BMW-801 lost performance rapidly above 20,000 ft. "

Kiwi sez-"To say that Soren agrees with you is to distort the truth. If that is the lengths you're prepared to go to, then it is an act in futility debating with you , because the debate can't proceed on a rational basis".

Wiki - You have to be either 'rational, or able to read and faithfully regurgitate what you comprehend for this debate to make sense. Go look at the series of discussions between Soren and my self starting with this comment



Originally Posted by Soren
Soren sez -"Btw, the figures from U-boat.net are interesting, noting a top speed of 515 km/h at 6,200m. Now top speed is never anywhere close to the service ceiling so somehing aint right.

Sources are very different on this bird..."

Kiwi - What do you make of this?

Refusing to read evidence

Kiwi sez-"I provided you with facts from NACA testing of the BMW-801 engine. It seems to me that you're reacting in a huff because you don't want to address those facts. Are you refusing to read the NACA report before mouthing off against it ?"

Kiwi - have you gone back and noticed that a.) I'm not reacting in a huff 'because I don't want to address those facts' - simply because I wasn't the one to 'mouth off against ANY NACA report!! You keep confusing my statements with someone else. Actually I don't mind defending myself against you but you seem to want all offensive statements (to you) laid at my feet!

Kiwi sez- "The engine performance chart published earlier at your post #93 is for rpm settings which change gear in the supercharger and change the engine from lean fuel to rich fuel.

SOREN posted 93 Kiwi!!!!! as he did many you attribute to me!

" 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."


Do you comprehend the d i f f e r e n c e between SOREN and DRGONDOG?

Kiwi sez - "The engine performance charts in the NACA report clearly show a jump in fuel consumption above 2150 rpm and above 20,000ft.

Glad to hear this, and your point is?

Kiwi sez-"Much earlier in this thread you asked me if I knew the optimum cruise altitude for the Ju-390. The NACA tests disclose the BMW-801 had a sweet spot from 14,000ft to just above 20,000ft where the performance and fuel consumption was steady at 17000rpm and 27 inches boost.

I think you have a problem with either 'the math' or 'reading comprehension' again. The Rpms sound like a dentist's drill - not a BMW 80. As for the AIRPLANE/ENGINE SYSTEM, what was the "sweetspot" for the Ju 390?

So now you are ready to deliver a chart which reflects either manufacturer's specs for cruise for the Ju 390 or flight tests and will state the payload, the altitude, the specific fuel consumption? Great - we have ALL been looking for that.

Kiwi sez -"I have earlier given you a source for reading test pilot Hans Pancherz's own notes and charts for the Ju-390. I see that you've made no effort to read those either."

You are drawing from memory - it hasn't been great. You have drawn from 'reading Pancherz's notes' - but there is no evidence of notes. You are basing your entire claim of NY trip based on his notes - but there is only his word. He bases his notes and his data on what? Nobody is quoting Junkers! I don't have access to the book. You apparently don't either. Does anybody think it is a good idea to have a fact based discussion? where are the FACTS.

Kiwi sez "Instead you're mouthing off that everyone else in the world is wrong except you

Nah


Kiwi sez -Repeating a false statement

I did not get the maths wrong. As explained, I rounded down the time to climb. You are engaging in misrepresentation. That is intellectual dishonesty. You've been told the facts. You keep denying them.

Here is specifically how you performed the math and BTW introduced the BMW 801E into the discussion

Kiwi sez- "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.

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.

The B-29 which had 80% higher wing loading and less power, took 25 minutes to reach 20,000ft. Actually at 120,000 pounds the B-29 has a wing loading of ~ 69 and at Max Gross TO of 133,000, ~ 76.

The Ju 390 according to 117,092 and 166,400 have ~42 and ~66 for wing area 2730sq ft. Where do you find an 80% difference? Is it the math?

So run six engines at boost for 15 minutes is 331.5 US gallons (1989lb)

Normal max operating consumption is 90-103 US Gal per hour per engine so let's keep climbing for another 10 minutes at 90 US Gal/engine...(54lb)

Okay so to reach 20,000ft the Ju-390 needed 25 minutes roughly and about 2043lb of fuel.

OK Kiwi - the above is what you said and the math you performed

I see 221x 6 engines for .5 hr + 331.5 gallons x 6.5 pound/gal = 2154.. plus 90x 6 x 1/6 hr x 6.5 = 585 pound

= 2739 pounds and 421 gallons

Call me crazy and opinionated about your 'math". Does the difference between your calc with your assumptions yielding 2043lbs versus 2739lbs look like a round off error to you? Explain your definition of "round off".. anything less than say 25% Ok with you?
QUOTE]

Kiwi - we can argue the weight of gasoline based on additives as being between 6.1 and 6.5 pounds per gallon, we can argue that the weight of cool gasoline is greater than 'warm'' but can we argue 90 gallons per hour x 1/6 hour (10 min) x 6 engines/@221 gal/hr is NOT 54 pounds ?

Is my statement 'false' or did you screw up the math?

Aces of the Luftwaffe - Walther Dahl Btw - here is another reference on Dahl

 

[drgondog]

The B-29 did not have a 80% higher wing-loading than the Ju-390, that's for sure. The difference in wing-loading was closer to 60%, which is still allot, BUT here's what I know:

Do you want to calculate the Wing Loading at 'normal operating range' or Max Gross Take off? We are talking about a Ferry Range Calc I think.

The Ju 390 is at 42#/ft2 at 117,000 and 61#/ft2 at 166,000 pounds? The B-29 is 69#/ft2 @120,000 (3300 mi range w/20,000 # bombload) and .76 @133,000# (basically all fuel plus crew) for 5800 mi.



The Ju-390 either used the BMW-801D or E engine, both were at a disadvantage at high altitudes, power decreasing rapidly above 22 - 23,000 ft. So although I do believe/know that the Ju-390's service ceiling was higher than 6km, it couldn't have been much higher than 8 to 9 km seeing that the performance of the BMW-801D E engines completely evaporated at those altitudes.

In short, the higher ceiling of the B-29 can attributed to its turbo-supercharged engines and more efficient wing. The Ju-390 no doubt could've gone higher than the B-29 had it had turbo-supercharged engines, however it didn't.

I agree the part about the Wright 3350-23A engines. If Baugher's data is correct, they had more Hp at 25,000 feet than at SL for Max Take Off Hp boost. Clearly the D-2 data you showed had a remarkable fall off at 15-18K ft..still have no comparable data for the 801E

 

[Soren]

I used the following figures to calculate wing loading:

Ju-390:
Gross weight: 53,500 kg
Wing area: 254 m^2

B-29:
Gross weight: 54,000 kg
Wing area: 161 m^2

That gives a 60% difference in wing-loading.

 

[drgondog]

I used the following figures to calculate wing loading:

Ju-390:
Gross weight: 53,500 kg
Wing area: 254 m^2

B-29:
Gross weight: 54,000 kg
Wing area: 161 m^2

That gives a 60% difference in wing-loading.

from Uboat

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.

From Warbirds

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)

from Military Factor

Length: 112.20 ft | 34.20 m
Wingspan/Width: 165.03 ft | 50.30 m
Height: 22.60 ft | 6.89 m
Empty Weight: 87,083 lbs | 39,500 kg
MTOW: 166,449 lbs | 75,500 kg

From Wikipedia

Specifications (Ju 390 V1)
Data from[citation needed]


General characteristics
Crew: 10
Length: 34.20 m (112 ft 2 in)
Wingspan: 50.30 m (165 ft 1 in)
Height: 6.89 m (22 ft 7 in)
Wing area: 254 m² (2,730 ft²)
Empty weight: 39,500 kg (87,100 lb)
Loaded weight: 53,112 kg (117,092 lb)
Max takeoff weight: 75,500 kg (166,400 lb)
Powerplant: 6× BMW 801D radial engines, 1,272 kW (1,730 hp) each

In other words - at 166,000 pounds the WL of the Ju 390 is 10#/sq ft less than the 133,000 pound ferry condition of the B-29. In other words 11% difference for the 'NY Run" we have been debating?

what is the real story on anything to do with the Ju 390?

 

[Soren]

Errr, why are we comparing the a/c at different loads ?

The gross weights of both a/c were very similar.

As for the NY run, well that certainly wouldn't have been carried out at max take off weight.

Btw, if talking about bombing the US then the Ju-390 wasn't the ideal choice with its low ceiling. The Ta-400 would've been ideal, however funding was cut as the LW initiated the fighter program.

 

[drgondog]

Errr, why are we comparing the a/c at different loads ?

The gross weights of both a/c were very similar.

As for the NY run, well that certainly wouldn't have been carried out at max take off weight.

Btw, if talking about bombing the US then the Ju-390 wasn't the ideal choice with its low ceiling. The Ta-400 would've been ideal, however funding was cut as the LW initiated the fighter program.

Soren - I put them out for the very reason you just asked the questions..

1. We don't know what the alleged NY run load conditions were.
2. We don't know what Maximum Gross Take Off conditions were with respect to any version that actually flew... so we don't know W/L would have been for the 'Ny Trip" at takeoff and climb
3. We don't know if a flying Ju 390 had either a bomb bay, or auxilliary tanks to store additional fuel in the fuselage, and don't know what the weight would have been in that case.
4. We don't know if the Service ceiling was at minimum fuel to get to the highest altitude possible, or whether that was a Service Ceiling for planned combat load.
5. We don't know power loading because we don't know the engine or the flight conditions we are calculating
6. We don't know what any version specifications were for cruise as function of weight and range and engine setting/altitude to achieve the cruise value

So why should anyone get excited about speculation on W/L comparisons, or ceiling calculations, or cruise speed/altitude for maximum range, etc.

What we know is one person claimed to have made a run to NY in one version of this airplane and we have no facts to judge the veracity of the guy.

 

[Soren]

Fair enough.

However with no bombs the Ju-390 could've easily made to the US and back, but with a big bomb load I doubt it. If the US was to be bombed by bombers flying from Germany or France the Ta-400 would be needed.

As for the service ceiling, well all German figures are for full weight conditions, that I know. However since we don't have the service ceiling of the Ju-390 we can only speculate as to what it was, and my guess is 8 to 9 km.

What are your thoughts Bill ?

 

[Denniss]

Regarding the engines: Most authors focussed on the aircraft and their design but not on engines or specific subtypes. Many authors still believe the Messerschmitt Bf 110 was powered by DB605A engines were in fact it was powered by DB605B engines. The same is with the BMW 801 powered Ju 88/Do 217 types, they used the 801A/L subtypes of the 801C or the G-2 subtype of the D-2.

The initial Ju 290 (prototypes/A-1) used 801A or 801L engines (yes, the bomber/multi-engined subtypes). At least with the A-5 they switched over to the BMW 801TL (Triebwerksanlage L containg the 801G-2 engine).

 

[drgondog]

Fair enough.

However with no bombs the Ju-390 could've easily made to the US and back, but with a big bomb load I doubt it. If the US was to be bombed by bombers flying from Germany or France the Ta-400 would be needed.

As for the service ceiling, well all German figures are for full weight conditions, that I know. However since we don't have the service ceiling of the Ju-390 we can only speculate as to what it was, and my guess is 8 to 9 km.

What are your thoughts Bill ?

I have opinions, and questions.

The opinions are: At least one Ju 390 was built in a passenger version originally, was tested and accepted - but contract was cancelled somewhere between one prototype and two. If the second one was built I suspect it was in a Recce version with provisions for internal tanks to extend loiter and range.

Because there is so much confusion regarding engines, I Suspect w/o any shred of proof that the first one was built with 801D and never intended to climb higher than 6000 meters, with the design passenger load. I suspect this version was closer, but less than a B-29 Ferry range.

I further Suspect that if the second one was built (either A-2 or V2) that it was equipped with 801E's to attempt a higher ceiling and cruise range for the Recce version.. I also suspect this is the one that is theorized to make the flight to US and back.

Based on the large capacity above the empty weight, I suspect that the quoted figure was for a version with internal fuel in fuselage for Recce version where passengers was not a factor. If that bird ever lifted 166,000 pounds at take off, this was the reason - pure long distance 'Ferry' condition.

The data presented agree on 87,000 pounds empty and 117,000 Gross Take Off (which I take for 'design internal payload' weight. So speculatively 30,000 pounds of ammo, crew and fuel for the original prototype is my Opinion.

So it seems the difference between 117,000 and 166,000 has to largely be additional INTERNAL fuel from my perspective - close to doubling the fuel capacity.

Even with more powerful 801E's this airplane would neither fly very high nor be efficient in cruise until it burned 2/3 of its fuel... but if it could carry 7-8000 more gallons of fuel, and actually get off the ground, I suppose it is possible to make that trip...

Questions still come back to the fundamentals - max fuel load, cruise speed and fuel consumption and altitude for the initial leg of the trip while burning down the extra fuel, then remainder of trip at 'standard' cruise and altitude after half the fuel is burned at lower cruise speed, lower altitudes and higher fuel consumption rates.

I still ponder the efficiency of this airframe/engine combination for cruise optimals. The 51 was a VERY efficient airframe/engine combo and able to optimize cruise Range at about 48gal/hr, 18,000 feet at low boost and rpms.

Do we believe that a series of BMW801s at near that fuel consumption as the efficient/powerful Merlin? I have no inkling or clue. An R-2800 sure couldn't come close which is why the Jug had to have 2x the internal fuel to fo as far.

This would be an interesting Performance Test for students..

As to your first question - if we guessed right that a.) first version prototype with the performance based on 117,000 pounds and 6km service ceiling, and a second one was built with primary difference being internal mod for fuel and BMW801E's - and w/o a chart to show relative Hp/altitude between the two, I would guess that with 200hp 'extra per engine that another 1 - 2 Km could be stretched... but at 117,000 not the 166,000 pound gross weght.

The 801E sgould cruise slightly faster for same sfc as the 801D, and higher for same fuel consumption - giving it probably a little more range - all things equal.

 

[pbfoot]

I read a little bit on the 390 at the hanger today by a gent named Heinz Nowarra and he states the 390 ferry range was 6000miles at 218 mph and 4900miles with a load ,

 

[Kiwikid]

I read a little bit on the 390 at the hanger today by a gent named Heinz Nowarra and he states the 390 ferry range was 6000miles at 218 mph and 4900miles with a load ,

That puts it's long range cruise about the same as a DC-4 / Carvair.

the NACA report on a BMW 801D2 engine from 1944 tests:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930093290_1993093290.pdf

Since last being online I read some further data at another forum on the BMW801E.

Phillip Willaume is a leading authority on the BMW engine and has done extensive research from various archives including the Simithsonian and British Archives. Some commentary on the BMW 801E engine based upon the engine's manual is available here:

A Complete Waste of Space Forums-viewtopic-bmw801

I have compressed the essential detail into a table here:

I have elsewhere seen figures for the BMW801D with a fuel flow of 55 US Gals per hour at 1700 rpm which based on this data would be at lower altitudes.

The opinions are: At least one Ju 390 was built in a passenger version originally, was tested and accepted - but contract was cancelled somewhere between one prototype and two. If the second one was built I suspect it was in a Recce version with provisions for internal tanks to extend loiter and range.

The Ju-390 V1 was converted from Ju-90 V6 with civil registration D-AOKD. This may be where the suggestion of a passenger transport arises.

Ju-290 A1 werke nr J900155 became the second Ju-390 with converstion at the Letov plant near Prague.

 

[psteel]

As I understand it , this entire debate hinges around the question of how the so called Ju-390 could have even made a round trip from Europe to America given that its range is some what short of what would seem to be required.

After some internet searching I gave up on the military forums and warplane sites and read up on civil aviation sites. Back in the 1980s I used to get AWST weekly and know that most aircraft range figures are theoretical calculations. For prop driven planes, the wind is by far the greatest factor that determines range.

When I pulled up my aviation charts for 5000-18,000 feet, it became painfully clear that if you know you wind streams at altitude you can vary your altitude and ride the wind currents across the Altantic [since they head west] and add up to 120 knts to your air speed and then drop to lower altitude heading back in the direction of Spain and negotiate around the winds ranging from 5-35knts with wind directions ranging from westerlies swinging around to northerlies, that could eventually push you back towards France.It would require a skilled crew that knew their winds at altitude...so it could be done in theory.

On a heavy weather day you can add an average of 50-60 knts to any round trip from France to America, which means in theory Ju-390 should be able to do the round trip with extra fuel tanks etc. As I recall they added some internal fuel tanks when the modified the Ju-290 to the 390 design. In fact after some tinkering it was also possible to get the Ju-290 to do the trip.... at a pinch ...also econo cruise at altitude, often had only a couple of engines running to conserve fuel

 

[pbfoot]

As I understand it , this entire debate hinges around the question of how the so called Ju-390 could have even made a round trip from Europe to America given that its range is some what short of what would seem to be required.

After some internet searching I gave up on the military forums and warplane sites and read up on civil aviation sites. Back in the 1980s I used to get AWST weekly and know that most aircraft range figures are theoretical calculations. For prop driven planes, the wind is by far the greatest factor that determines range.

When I pulled up my aviation charts for 5000-18,000 feet, it became painfully clear that if you know you wind streams at altitude you can vary your altitude and ride the wind currents across the Altantic [since they head west] and add up to 120 knts to your air speed and then drop to lower altitude heading back in the direction of Spain and negotiate around the winds ranging from 5-35knts with wind directions ranging from westerlies swinging around to northerlies, that could eventually push you back towards France.It would require a skilled crew that knew their winds at altitude...so it could be done in theory.

On a heavy weather day you can add an average of 50-60 knts to any round trip from France to America, which means in theory Ju-390 should be able to do the round trip with extra fuel tanks etc. As I recall they added some internal fuel tanks when the modified the Ju-290 to the 390 design. In fact after some tinkering it was also possible to get the Ju-290 to do the trip.... at a pinch ...also econo cruise at altitude, often had only a couple of engines running to conserve fuel

the only problem is the LW would have no.... absoulutely no knowledge of those winds aloft the best info the might get would be surface winds from U boats flying the pond was a relatively new sport and the only ones that might be aware of those winds and their trends would be the Ferry Command guys and MATS

 

[Graeme]

the only problem is the LW would have no.... absoulutely no knowledge of those winds

The Focke Wulf Condor transatlantic flights of 1938 must have gleaned some information on the wind forces for the Germans?

On a heavy weather day you can add an average of 50-60 knts to any round trip from France to America

From..Transatlantic flight - Wikipedia, the free encyclopedia

"August 10, 1938 - first non-stop flight from Berlin to New York. The Focke-Wulf Fw 200 needed 24 hours, 56 minutes and did the return flight three days later in 19 hours, 47 minutes."

How did that Condor return faster on the return flight?

 

[pbfoot]

The Focke Wulf Condor transatlantic flights of 1938 must have gleaned some information on the wind forces for the Germans?



From..Transatlantic flight - Wikipedia, the free encyclopedia

"August 10, 1938 - first non-stop flight from Berlin to New York. The Focke-Wulf Fw 200 needed 24 hours, 56 minutes and did the return flight three days later in 19 hours, 47 minutes."

How did that Condor return faster on the return flight?

Prevailing winds but to know the winds aloft is still some what of a mystery to this day for example wind shear , look at the local winds aloft for your location they can vary a number of degrees from surface winds the winds here vary by 30 degrees at 3000 ft and are 20 knots faster at this location right now

 

[Graeme]

can vary a number of degrees from surface winds the winds here vary by 30 degrees at 3000 ft and are 20 knots faster at this location right now

Roger that pb.