WWII MISTERIES: What happened with the JU390?

[Kiwikid]

And your irrefutable source for this is?

And your irrefutable source that they did not is ?

Besides which you're arguing the toss about a pimple on a gnat's bum. If it was the BMW-801E engine then so much the better because the E engine had slightly better fuel consumption. You're really taking your arguments to immature lengths.

[drgondog]

Originally Posted by Kiwikid

You mean like you took me too literally about Ju-390 climb to 20,000ft to suggest I got my maths wrong ?

No, I took your incorrect math to be wrong

... 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.

If you are talking about a P-51B, check the dates again on Dahl

Walther Dahl flys the P-51

You may have a reading comprehension issue. The Zirkus was formed in 1943 as it stated but Dahl didn't fly the 51 until the next summer. The first ETO thunderbolt also mentioned in the article was Beetle Roach's 358FS/355FG P-47D 42-22490 "YF-U" - MACR 1281, ran out of fuel and landed nw Liege in November 1943

Hungarian pilots were taught mock combat against captured Mustang T9+HK. That would date these flights to before Hungary capitulated to the Allies in March 1944.

They didn't fly mock combats in a P-51B before March 1944..

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

Hans Lerche flew the first captured intact Mustang back from France on June 6, 1944, according to him, in his book, Luftwaffe Test Pilot. Your source would be what?

Strangers in a Strange Land recounts the same date

My understanding is that Dahl flew the 51 for the first time just about the time IV./JG3 was equipped with the Fw 190A8, when Rall was running the program while recovering from his May 12, 1944 WIA. I am NOT sure of this, but I will check

[drgondog]

Originally Posted by Kiwikid

And your irrefutable source that they did not is ?

Besides which you're arguing the toss about a pimple on a gnat's bum. If it was the BMW-801E engine then so much the better because the E engine had slightly better fuel consumption. You're really taking your arguments to immature lengths.

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

WRG - Luftwaffe Resource Group - Junkers Ju 390

The point that eludes you is that there are ZERO irrefutable sources regarding

a. Its engines (both of the above state 801E but I have seen reference to 810D also)
b. It design specifications including maximum fuel capacity (no, your 'unequivoval' statement of 10,000 gallons does not meet 'standard' of veracity or 'irrefutable'
c. ANY specifications regarding cruise speeds as function of payload, altitude, fuel consumption, throttle settings, etc
d. ANY data regarding fuel flow and/or rpms and/or boost for the 801D or the 801E for any aircraft in cruise condition - at least not in these discussions.

But you, (as a pilot) are quite happy to rattle away with flight profiles, cruise range, ceilings, specualtion about cruise speeds etc ????? to try to prove someone ELSE is wrong when they assert that there is no proof that the Ju 390 flew to NY and back?

Why?

[Kiwikid]

While Soren and I still believe the stated ceilings are wrong (6,000 m), that would suggest that 20,000 feet is un attainable under ordinary circumstances with a full load?

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.

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.

Refusing to read evidence

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 ?

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.

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

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 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.

Instead you're mouthing off that everyone else in the world is wrong except yourself. For example:

You got the math wrong. This is a fact. You cleverly walked us through your own calculations

While Soren and I still believe the stated ceilings are wrong (6,000 m), that would suggest that 20,000 feet is un attainable under ordinary circumstances with a full load?

If the stated 801E reference is more reliable than you, then 1970Hp was achieveable... so which Hp table for the 801E do you wish to use? and at what altitude? Please post a reference chart.

See above. A realistic figure would be Never if the data are correct for the Service Ceiling. If you wish to refute the stated service ceilings then produce a fact based reference to show they are wrong and you are right.

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.

Richard Leonard got the maths totally wrong yet you're selectively silent on this.

I have to walk you through my calculations because you're determined to see failed maths where I simply rounded down my own estimate.

20,000ft is not unobtainable. You have never responded to the fact that the Ju-390 has superior wing loading, superior power to weight and more horsepower than the B-29. That's just slightly inconvenient for you isn't it ?

You've also been told that the engines are altitude limited. Not based on what I say but based on published engine performance charts.

I have quoted to you an authoritative wartime intelligence report based on proper tests of the BMW-801D2 engine. The BMW-801E is merely a D2 with higher compression on it's centrifugal compressor.

You asked for a source. I have given you the NACA report.

See above. A realistic figure would be Never if the data are correct for the Service Ceiling.

Well how fascinating ?

So according to Drgndog, Hans Pancherz the Ju-390 test pilot is wrong.

So according to drgndog National Advisory Committee for Aeronautics spent months testing the BMW801D2 but according to drgndog they got it wrong too.

Given the superior weight and power ratios, if the Ju-390 couldn't reach 20,000ft then neither could the B-29 nor the B-36 with inferior ratios.

Ah but don't worry drgndog because I notice you're not letting a simple thing like facts get in your way.

[Kiwikid]

By Faustnik (acompletewasteofspace.com)This is from a thread in the ORR board. Crumpp, of the White One Foundation, has answered some important questions on the BMW801D, TS & TH powerplants. With his permission, I am reposting them here.

The BMW801D went through numerous technical upgrades throughout its lifespan. Everything from exhaust changes to redesigned piston and cylinder sleeves from the 801E development program added in early 1943. fuel improvements, timing adjustments, plugs, fuel pumps, exhaust changes both to the pipes and the exit ports all contribute to the growing power of the motor.

A Complete Waste of Space

But you, (as a pilot) are quite happy to rattle away with flight profiles, cruise range, ceilings, specualtion about cruise speeds etc ????? to try to prove someone ELSE is wrong when they assert that there is no proof that the Ju 390 flew to NY and back?

That's an interesting and self contradictory statement by you. Let me recall what you said at post #66:

Excellent analysis Rich - and to add to the equation, load another 10,000 pounds as a payload - and take 10,000 pounds of fuel off the table for the 'nuke' part of the story.

so when you say:

...to try to prove someone ELSE is wrong when they assert that there is no proof that the Ju 390 flew to NY and back?

...does that mean you exclude yourself and Richard Leonard from those trying to prove there is no proof ?

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"

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

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

You're hardly pursuing an objective debate drgndog

[drgondog]

[quote=Kiwikid;331922]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]

Originally Posted by Kiwikid;331932

Bill sez to Kiwi -"But you, (as a pilot) are quite happy to rattle away with flight profiles, cruise range, ceilings, specualtion about cruise speeds etc ????? to try to prove someone ELSE is wrong when they assert that there is no proof that the Ju 390 flew to NY and back?

Kiwi sez- "That's an interesting and self contradictory statement by you. Let me recall what you said at post #66:


Quote: (from Drgondog to Rich Post)
Bill sez -"Excellent analysis Rich - and to add to the equation, load another 10,000 pounds as a payload - and take 10,000 pounds of fuel off the table for the 'nuke' part of the story. "

Kiwi - "so when you say:

Quote:
Bill sez ..."to try to prove someone ELSE is wrong when they assert that there is no proof that the Ju 390 flew to NY and back?"

Kiwi sez "...does that mean you exclude yourself and Richard Leonard from those trying to prove there is no proof ?"

[B

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]

Originally Posted by Kiwikid

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.

[url=http://members.aol.com/kaczmarek190/rosarius.html]

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]

[quote=drgondog;331942]

Originally Posted by Kiwikid

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]

Originally Posted by 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:

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]

Originally Posted by 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.

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
<