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Soren - by the same logic LW leaders could not believe a single engine fighter like the Mustang, with extremely high performance, could escort daylight bombers past Berlin..
I've never heard of the Germans displaying any disbelief on that subject, esp. seeing they had captured quite a few examples of this a/c and thuroughly tested it in both flight and windtunnel tests. The tests ending with the conclusion the airfoil was disadvantaguous in all other aspects but drag reduction in straight flight.
The range of the Mustang was mostly due to its fuel capacity, a/c with similar fuel capacities flying similar distances.
32 hours 6000 milesYou'd need to know either the time or cruise speed along with distance to establish this Pbfoot.
So where did you get the 187 knot figure from ?
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...
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 don't have the Mean Chord for either but the Span>>2/Area gives 10 for the 390 and 11.5 for the 29, so it is significant.
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.
As for the P-51, we agree.
drgndog said:
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'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.
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.
2) The Ju 390 did at least use the G-2, you can't use a D-2, geared for small and fast aircraft, in an aircraft that big and slow.
Thank goodness I missed this ridiculous bun fight.
The Ju-390 has been quoted as using both the BMW-801D and BMW-801E engine. The "E" engine was experimental and never saw widespread use. The "E" engine had 2.5% better fuel performance.
And your irrefutable source for this is?
The "E" engine differed in gearing for higher altitude and a better cooling fan/compressor. The figures for a BMW-801E are so marginally different as to be minimal and if you insist on the Ju-390 having flown to New York with BMW-801E engines then so much the better because that engine had slightly better fuel performance.
Depends on who you think is insisting?
Until i see cruise figures for the Ju 390, designer specs for fuel, real cruise settings for the BMW 801E for both max endurance and max distance - all of this discussion is essentially a 'legend'? IIRC You were the one that jumped in, insisted that it did and proceeded to screw up the math for your own assumptions
Drgndog you've quoted figured like 56 inches boost. That's claptrap!
??? are you referring to the P-47D-10 test figures I posted for Soren? Otherwise what are you talking about
I see however where you've made the mistake drgndog and it is understandable.
Yes you've published a report on BMW-801D performance in a range of rpm settings from 2150rpm to 2750rpm. (post#93)
Wiki - you have established three things so far.
1.) you can't do math to validate your own assumptions, 2.) you can't post anything of relevance to back up your assumptions, and 3.) you can't sort out who did what in this discussion.
I haven't posted ANYTHING on either the 801E or D or D-2 other than to refer to multiple references citing the multiple versions that independently claim the Ju 390 only flew in the V1 version, then the A1 version, then an A1 and A2 then a V1 and V2 then one cited the only one to fly of the V1 had a BMW801E.
Soren posted a performance chart for the D-2. So far you have posted nothing to back up your statements>
What you seem unaware of Drgndog is the BMW-801D (and E) had an automatic fuel control system.
You are correct. What I KNOW about the 801E can be written on the back of a matchbook cover with a paintbrush. I have not claimed expertise in the 801 of any series. You and Soren are having the expert discussion. So far he has posted data to back up the D-2, and you???
When run above 2150rpm the automatic fuel control switches the supercharger from low to high gear and fuel from lean to rich. That is why you have a table with much higher fuel consumption. It pays to cite facts in context.
Agreed. See above. Also note that facts without source of 'facts' is often dealt with some degree of scepticism.
The context is that this engine would not have been run at such settings by the Ju-390 except on take off and even then only for limited time.
On the other hand a P-47D-10 with an R-2800 might..
You've cited a table for a fighter plane performance at high boost, high rpm and rich fuel mixtures. That does not translate to a Ju-390 at lower rpm with lean mixture and low boost.
Maybe because the table for fighter performance at high boost, high rpm and rich fuel mixtures were for a P47D-10? Last time I checked that WAS considered a 'high performance' fighter in its day?
As I have stated before I did not get the math wrong. I rounded down because I did not accept given the low wing loading that the climb would have been so protracted.
You got the math wrong. This is a fact. You cleverly walked us through your own calculations
An Fw-190 A5 would reach 20,000ft in 15 minutes. I calculated that a Ju-390 would reach 20,000ft in 25 minutes because that is the time a fully laden B-29 needed to reach 20,000ft.
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?
Then I rounded it down as you say by 20% because the Ju-390 has only 55% of the B-29's wing load and 18% more power. The Ju-390 also had an 85% better power to weight ratio than the B-29.
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.
A realistic figure for the ju-390 to reach 20,000ft would be about 20 minutes, so please stop misleading people.
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.
I did not get the maths wrong. I rounded down because I knew that the fuel consumption for a 25 minute climb was excessive and not supported by fact.
So far everything you have written falls short of 'fact'
The math which you say I got wrong was an "ESTIMATE" for the climb. The maths for the cruise was essentially correct. the climb to altitude was an estimate... nothing more ...nothing less.
I fully understand a.) you were making assumptions, b.) you have nothing to back up your assumptions, and c.) your math based on your own assumtions was wrong
If you want to split hairs drgndog, had I assumed the same 15 minute time to altitude figures I could have halved the fuel estimate for the climb and you'd be none the wiser so please stop engaging in cheap shots.
My lack of wiseness in this discussion is based soley on conflicting references, no data from an accomplished pilot like yourself, no credible flight plan for a Ju 390 attempting a flight to New York, etc - THAT WOULD SUPPORT anything you have written so far.
If you want an honest debate then don't use intellectual dishonesty to win the debate.
Go find 'dishonesty' if you please?
In an altitude range of 14,000ft to 20,000ft with the early two stage supercharger used on "D" and "E" engines the manifold pressure at cruise settings of 1700hp and leaned fuel was 27 inches of mercury.
The supercharger did not change gear until 2150 rpm.
I am glad to hear that drgndog because NACA performed the tests you've referred to on the BMW-801D2
ROFLMAO - find ANY spot in the universe where I posted that!!
My information comes from the National Advisory Committee for Aeronautics (NACA) forerunner to NASA, Memorandum report #E5D19 "Characteristic of the BMW 801D2 Automatic Engine Control."
Flying at lean cruise settings and supercharger low gear up to 20,000 ft, the BMW-801D engine only burned 56.66 US Gals per hour. The "E" engine used 2.5% less fuel per hour.
Soren the BMW 801D2 would reach 36,000ft if pushed, but that tripled the fuel consumption. Critics of the New York flight cite BMW-801 fuel consumption at maximum power with rich fuel mixtures and high boost to justify claims that the flight couldn't have happened.
It sure wouldn't take a Ju 390 to 36,000 feet... not if Soren's figures on the D-2 are correct
It's intellectually dishonest to cite such power settings as typical of a New York flight. No aircraft cruises at maximum power on a long range flight.
Finally you have made a statement I agree w/o facts to base it
Through a process of logical deduction the cruise speed for such a mission appears to have been a very slow 167 knots at 20,000ft.
And you arrive at this how?
BMW-801E
The BMW801E engine: Version E was in fact modified D-2 used for prototype testing. It would have developed 2000hp in bench tests. It seemed to be produced in small number and to be delivered under designation TG and/or TH.
At take off power the BMW-801D used 200 US Gal per hour but could only maintain this for 3 minutes before overheating required throttling back.
At take off power the BMW-801E used 195 US Gals per hour. It also used water methanol injection to the supercharger intake at take off.
The biggest difference was a centrifugal air compressor which pushed air pressure from 1.39 atmospheres for the BMW-801D up to 1.62 atmospheres for the BMW-801E.
This site gives a run down of distinctions in BMW801 engine types.
focke wulf 190 moteur bmw bmw801 bramo
There may also be confusion about the BMW-801E and BMW-801G because the BMW-801E was also known as the "TG"
Not quite correct Denniss as the Ju-290 sisters of the Ju-390 all had the BMW-801D engines.
I have seen references that the Ju-390 had both D and E type engines and one supposes that the E type was introduced after the first Ju-390 flights as an attempt to get better performance.
The gearing was in the supercharger and I have read of 4 stage superchargers late in the war.
You took me a little too literally.
On the other hand the Luftwaffe didn't capture a Mustang until 3 months after the first Berlin escort mission. June 6, Cambrai. So they performed zero wind tunnel tests on the airframe until after June, 1944. The first one crashed and both the pilot and a/c were lost after Lerche flew it for some time. Look to pages 117-119 of his book.
Note his comments that of all the Me and Fw series of piston engine fighters flown by Luftwaffe aces in comparative tests, only the Dora and the 109G-10 'could more or less keep up with it.
As to the analogy I used. It was only after wind tunnel tests that they had a true understanding of the extremely low drag of the Mustang.
May I also draw your attention to the flat plate and wetted drag comparisons you showed a couple of weeks ago? The range was Definitely not Only due to fuel capacity.
Look to P-38, P-47 and F4U internal fuel capacity versus Mustang and re-think the point?
As to 'quite a few'captured, the number was IIRC two or three B's and one or two D's... the very first example on D-Day as noted above. The one picture I have seen of the first P-51D before LW colors were applied indicated September-October timeframe based on the Invasion stripe scheme and lack of nose cowl/rudder color scheme assigned to each fighter Group
The site you linked has lots of errors. No large (bomber) aircraft used a 801D-2 or similar fighter engines, they all used the G-2 or similar bomber subtypes.
And your irrefutable source for this is?The Ju-390 has been quoted as using both the BMW-801D and BMW-801E engine. The "E" engine was experimental and never saw widespread use. The "E" engine had 2.5% better fuel performance.
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.
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.
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?
You got the math wrong. This is a fact. You cleverly walked us through your own calculations
An Fw-190 A5 would reach 20,000ft in 15 minutes. I calculated that a Ju-390 would reach 20,000ft in 25 minutes because that is the time a fully laden B-29 needed to reach 20,000ft.
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?
Then I rounded it down as you say by 20% because the Ju-390 has only 55% of the B-29's wing load and 18% more power. The Ju-390 also had an 85% better power to weight ratio than the B-29.
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.
A realistic figure for the ju-390 to reach 20,000ft would be about 20 minutes, so please stop misleading people.
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.
See above. A realistic figure would be Never if the data are correct for the Service Ceiling.
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 prototype BMW801TS (BMW801D2V15) was tested in July 1942. Many of the changes were simply incorporated into the BMW 801D2. There is little to choose between the motors with the exception of the BMW801TS 1.65ata "Start-und-Notleistung" rating. "Start-und-Notleistung" rating is reserved for the engines highest output without an antiknock agent injection. Since the BMW801D2 received the pistons and sleeves of the TS series in 1943, it is pure speculation, it may very well have been cleared for 1.65ata "start-und-notleistung" as well sometime later during the war.
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.
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?
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.
...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?