Questions about the Me-262

[syscom3]

Soren, so can you list the production figures (for 1944) of the Jumo, as accepted by the LW?

 

[HoHun]

Hi Syscom

>can you list the production figures (for 1944) of the Jumo, as accepted by the LW?

Here is a graph showing early Jumo engine life data.

The diamond signifies the acceptance run of each engine, the coloured bar the use (blue: flight testing, red: ground testing, green: not explained, must be delivery). An X means the engine was "terminated".

Time is on the left-hand axis, engine serial is on the top axis, grouped by engine type.

The graph was on display in the Luftfahrtmuseum Hannover-Laatzen, who have Jumo 004A-022 on display.

Regards,

Henning (HoHun)

 

[kool kitty89]

I'm not sure I see the green marks, whaich ones are you referring to?

And the diamons you are reffering to are at the top of the bars? (they look more like circles)
Or are you reffering ti the dots at the bottom of the bars?

 

[HoHun]

Hi Koolkitty,

>I'm not sure I see the green marks, whaich ones are you referring to?

It's my impression that the marks on the right-hand side of the diagram are green, starting around Jumo 004B-020. However, using the colour-analysis tool with the full-size original reveals that there are more blue pixels than green pixels in there, so I guess my "green" is actually supposed to be blue, too.

>And the diamons you are reffering to are at the top of the bars? (they look more like circles)

Yes, the diamonds are the circles at the top of the bars

Regards,

Henning (HoHun)

 

[kool kitty89]

What does the dot at the bottom of some the bars mean? (opposed to the X which would mean a failure or an otherwised compromised engine)

 

[HoHun]

Hi Koolkitty,

>What does the dot at the bottom of some the bars mean? (opposed to the X which would mean a failure or an otherwised compromised engine)

I could only guess. Even the X is uncertain, "Absetzung" is not really an accurate term if you don't know the specific Junkers usage.

LEO Results for "absetzung"

Regards,

Hennnig (HoHun)

 

[kool kitty89]

I got "Joggle" when I tried to translate it using Yahoo! Babel Fish - Text Translation and Web Page Translation

 

[syscom3]

According to this chart, it looks like the LW only had enough engines (by the end of April 1944) to only equip ALL of their jets in the test units.

A more telling figure would be to see the number of engines on hand and available for use at the end of Aug 1944.

 

[kool kitty89]

Also note that in the graph's timeline the latesest engines are the pre-production 004B-0's so we haven't even gotten to the first production models. (B-1)

 

[HoHun]

Hi Syscom,

>According to this chart, it looks like the LW only had enough engines (by the end of April 1944) to only equip ALL of their jets in the test units.

Note that the graph only indicates engines accepted until March.

So how many jets were in the test units by the end of April 1944?

Regards,

Henning (HoHun)

 

[syscom3]

Ok, this is what I have figured out from all of your opinions and facts.

1) The LW didn't have a lot of airframes untill the end of 1944. And even then, the availability rate must have been low to begin with, thus the number of 262's available on any given day was quite low.

2) Inadequate training and poor tactics meant that it had a low kill per sortie untill 1945.

Now , I am wondering this. If the 262 had been employed more effectively in Dec 1944 or Jan 1945, would the allies been able to limit its effectiveness by saturating with a CAP over the airfields and hitting them with medium bombers prior to the heavy bombers entering German airspace?

 

[HoHun]

H Syscom,

>And even then, the availability rate must have been low to begin with

Why "must"?

>2) Inadequate training and poor tactics meant that it had a low kill per sortie untill 1945.

"Low" meaning "not more than 1 kill per sortie" in your book?

>If the 262 had been employed more effectively in Dec 1944 or Jan 1945, would the allies been able to limit its effectiveness by saturating with a CAP over the airfields and hitting them with medium bombers prior to the heavy bombers entering German airspace?

That's what they historically did.

Regards,

Henning (HoHun)

 

[razor1uk]

IIRC, as stated already by some, they're's many reasons as to why the 262 and in particular the manufacturers of both airframes engines not always being able to do they're jobs more effectively.
I think if the connected sub thread topic with regards the 04's 03's, gets more... I'd maybe have to show some info from a book I have; German Jet Engines Gas Turbines 1930 - 1945, it is an engineering devolopment history, technically very good, but a boring read if your after a good read.

I wouldn't knock musical experts helping 'tune' aspects of the engines, back then before electronic computers, with regards to resonance, vibration and however you wish to term it, fluctuations within something be it air, metal etc, are stll fluctuations, and as such, equivelent in an analogeous way to sound - music.

The support spiders had there own fairings - seperate to the once used for engine control/regulation by hydraulic, pneumatic, geared shaft or other means.
Due to resonance, the later designs of how the outer arms of the spiders passed through the engines airflow was changed from equally spaced and the uniform hormonics created by them.
To having the arms unequally aligned/spaced to cancel or to shift their harmonc range they imparted in to the airflow away from other problematic engine vibrations and airflow cavitations ranges in an attempt to provide better running at.. general operating speeds/usual harmonics and the like, this gave a slight increase in fuel efficenecy, lessened combustion fluctuations at which also gave some benifits to engine life from more stable combustion.
Apologies, I have summed up a few years of technical back and forth of early German jet development into a few paragraphs.

 

[johnbr]

The book German Jet Engines Gas Turbines 1930 - 1945 sat on the shelf for or 20 yrs before it was published and when it was it got no updating.It was to have rocket engines in it to but the publisher said to take it out.

 

[TomM]

The book German Jet Engines Gas Turbines 1930 - 1945 sat on the shelf for or 20 yrs before it was published and when it was it got no updating.It was to have rocket engines in it to but the publisher said to take it out.

Do you have a copy? Any chance it has a schematic for the Reidel starter motor???

 

[GregP]

Me-262 pilots claimed a tiotal of 562 Allied kills against a loss of about 100 aircraft. As we know today, the real kills are considerably less than claims. So it is likely the real kills are in the neighborhood of 150 -200, if Me-262 claims follow the claims from other types. That is a kill ratio of about 5.6 : 1 for claims and probably near 1 : 1 to 2 :1 in real life. Unimpressive for a new "technological wonder." Even if the real kills are as high as, say, 350, the ratio is unimpressive, especially since the losses are much better documented.

The Me-262 had a 60 pounds per square foot wing loading, and was easy for any piston fighter to out-turn. Of course the real vulnerability was during takeoff or landing where the Me-262 was unmaneuverable and unresponsive in the extreme. In the Me-262's best performance, it cost the Allies 12 planes from a 1200 plane raid, a 1% loss. It never got that good in another engagement. Even the Brewster Buffalo (in Finnish service) did better.

That, of course, is with hindsight since I KNOW the results. To me, the Me-262 was a neat look at the future that was relatively ineffective. It did little to win the war and cost a lot of resources. Of course, the results could not have been known in advance and the Germans probably needed to expend the Me-262 effort in order to try to make a dent in the large daily Allied bomber streams.

In the end, although it pointed heavily to the future, the Me-262 was a failure as a fighter, a failure as a bomber destroyer, and a failure as a weapon. It was a wonderful experiment that was simply not ready for the challenge in time to make be effective enough to make a difference.

I know many in here revere the Me-262 and that is OK. I am simpy not one of its admirers, except as the "first of the beed" of jet fighters that owed a lot to the Me-262's design and combat tactics. For that, it deserves its place in history as an innovative aircraft that was ahead of its time.

 

[Siegfried]

Me-262 pilots claimed a tiotal of 562 Allied kills against a loss of about 100 aircraft. As we know today, the real kills are considerably less than claims. So it is likely the real kills are in the neighborhood of 150 -200, if Me-262 claims follow the claims from other types. That is a kill ratio of about 5.6 : 1 for claims and probably near 1 : 1 to 2 :1 in real life. Unimpressive for a new "technological wonder." Even if the real kills are as high as, say, 350, the ratio is unimpressive, especially since the losses are much better documented.

The Me-262 had a 60 pounds per square foot wing loading, and was easy for any piston fighter to out-turn. Of course the real vulnerability was during takeoff or landing where the Me-262 was unmaneuverable and unresponsive in the extreme. In the Me-262's best performance, it cost the Allies 12 planes from a 1200 plane raid, a 1% loss. It never got that good in another engagement. Even the Brewster Buffalo (in Finnish service) did better.

That, of course, is with hindsight since I KNOW the results. To me, the Me-262 was a neat look at the future that was relatively ineffective. It did little to win the war and cost a lot of resources. Of course, the results could not have been known in advance and the Germans probably needed to expend the Me-262 effort in order to try to make a dent in the large daily Allied bomber streams.

In the end, although it pointed heavily to the future, the Me-262 was a failure as a fighter, a failure as a bomber destroyer, and a failure as a weapon. It was a wonderful experiment that was simply not ready for the challenge in time to make be effective enough to make a difference.

I know many in here revere the Me-262 and that is OK. I am simpy not one of its admirers, except as the "first of the beed" of jet fighters that owed a lot to the Me-262's design and combat tactics. For that, it deserves its place in history as an innovative aircraft that was ahead of its time.

1 It was certainly possible for a piston engined fighter to turn inside an Me 262 when at full speed, it was however NOT possible for say a P-51 to out turn the Me 262 and get on its tail. The Me 262 could simply fly faster around the outside of the circle. Turn radious and turn rate are different. The Me 262 had full span leading edge slats, which apart from increasing coefficient of lift by 40% probably helped with spanwise flow issues from the wing sweep but also gave it a slightly higher Mach than the P-80A and Meteor III since Mach dimmimishing wing twist (washout) was unnecessary; moreover it gave the aircraft a gentle well annuciated stall in all conditions.

The Me 262 was not a failure, by the time it was fully ready, around October/November 1944 the D-day invasions had created an impossible situation for it. The over claims of Me 262 pilots need to be considered in the context of all of those overclaims of allied aircraft that claimed to have bagged an Me 262 but simply fired their guns in anger and saw the small group of Me 262 (often only two) disengage witth the typical soote produced by early turbojets. Their common sense tactics involved full use of their stunning speed advantage precluded interest in a dogfight except perhaps to rescure a buddy. Me 262 shot down several Mustangs but I doubt they were silly enough to repeatedly use their speed advantage to position themselves for repeated boom and zoom tactics while the Allied fighters mustered their superior numbers.

Some of the technology designed to support the Me 262 was simply stunning: The Elfe gunnery computer which integrated a FuG 248 ranging radar with the EZ-42 or EZ-45 lead computing gun sight would have made the Me 262 a monster as it allowed accurate long range and flank attacks by both unguided missile and gun. The TSA-2D toss bombing sight, which did see some trials level combat service, allowed accurate bombing attacks from the jet.

The Me 262 was delayed by its engines protracted development. It's likely that the Jumo 004 could have been made available several months earlier in a reliable form. The engineering mistake was not to fully develop the fuel control system to moderate throttle demanded fuel flow in consideration of actual engine air mass flow conditions. This was a mistake typical of all of the early jet engines; allied and German. In reality the fuel controls needed to be about as complicated as the fuel injection system and integrated propeller rpm and pitch system used on a typical German mid war fighter engine. Another decision was to be excessively frugal in use of refratory materials, bearings etc. These decisions were all forced errors caused by shortages of specialist materials, labour and damage to factories. The allies, particulary the Americans who were safe on the other side of the Atlantic with a plentifull nickel supply in Canada never had to face.

Erhardt Milch is said to have stated that the Me 262 needed to be ready by 1943 for it to change the course of the war, he was probably correct though even then if the aircraft had of been advanced by 6 months to say 3 months before the d-day landings to 3 months after its impact would have been considerable: especally in the area of photo reconaisance.

German alloy development as well as turbine blade design did apparently progress. In addtion there were two other avenues; water cooled turbine blades and ceramic turbine nozzle blades. Both were in an experimental stage. Both systems work quite well but have not found much use in modern engines as alloys have allways managed to stay one step ahead of ceramics and avoid the complications of a water recirculation system.

 

[Siegfried]

Also note that in the graph's timeline the latesest engines are the pre-production 004B-0's so we haven't even gotten to the first production models. (B-1)

The B-0's were reputadly more reliable than the B-1's, a reversal of the usual order, since the engines experienced quality issues from mass production. A major improvement in reliabillity came around November with the introduction of deep drawn hollow aircooled blades of the same tinidur alloy in the B-4 (or B-3) engines. Febuary also sees supllimentary service use of hollow trailing edge seam welded turbine blades of the alloy Cromidur; this inferior alloy was actually somewhat superior in actual use due to ease of m. April was supposed to see introduction of a new fuel control system, which would have maintained turbine temperature conditions within tighter parameters as well as prevented flameouts from throttle handling as well as prevent turbine damage from excess fuel burn. Such a system did make it into service on the little used BMW 003 engine (on He 162 and Ar 234C)

 

[riacrato]

Me-262 pilots claimed a tiotal of 562 Allied kills against a loss of about 100 aircraft. As we know today, the real kills are considerably less than claims. So it is likely the real kills are in the neighborhood of 150 -200, if Me-262 claims follow the claims from other types. That is a kill ratio of about 5.6 : 1 for claims and probably near 1 : 1 to 2 :1 in real life. Unimpressive for a new "technological wonder." Even if the real kills are as high as, say, 350, the ratio is unimpressive, especially since the losses are much better documented.

Wrong way to look at it. The kill-loss ratio of other German fighters in the same time period those 562 claims (allegedly) were made was certainly much, much worse. I dare say that, even though I have zero data at hand. I have read claims from former USAAF pilots it was as bad as 1:10, maybe the real figure is 1:5, hard to say. So the Me 262 was a vast improvement over the current piston engined LW fighters (including Fw 190 Ds) and that is what counts. The fact that any LW daytime fighter was at all able to score an even ratio under those circumstances is astonishing.

Relatively speaking.

Regarding the total outcome, the Me 262 was but a drop on the hot stone, as we say in Germany.

 

[Milosh]

Over claiming of Me262s

March 24 1945

31 Me262s took off in 2 groups, Stab and 11./JG7, and 9. and 10./JG7
The first group claimed 5 B-17s. The second group claimed another 5 B-17s.

The USAAF 31st and 322cd FGs claim 8 Me262s. Only 4 Me262s were lost.

Uffz Giefing 11./JG7 in WNr 110968 near Grussen
Lt Ambs 11./JG7 in WNr 110999 near Wittenberg
Oblt Worner 9./JG7 in WNr 111676 near Northeim/Harz
Oblt Kulp unknown WNr

All survived.

I./JG7 claimed 2 P-51s and a P-38 near Neumunster though no P-38s were lost.

Obslt Bar III.EJG2 claimed a B-24 and P-51.