109 it fly wrong

[HoHun]

Hi Gripen,

>That's exactly the problem; the chart might not be based on real tests or the test data  contains just couple test points.  

Well, that's standard operation procedure in flight tests. You'd probably do speed runs for example in 1 km intervals, plus one or two runs at the full throttle heights, and that's not quite enough to get details like the curvature perfectly right.

The Russians definitely tested several Gustav aircraft. According to Carl-Frederik Geust's "Under the Red Star" the NII VVS got 650 km/h @ 7000 m from a Me 109G-2/R6, and 16 - 19 km/h more from a clean Me 109G-2 (W.-Nr. 14513).

So the Tsagi book graphs showing around 670 km/h @ 7000 m seems very credible to me. As you already pointed out, the shape is not perfect, but I'd consider that a rather minor difference.

Regards,

Henning (HoHun)

[HoHun]

Hi Isegrim,

>Just checked the Soviet speed curves vs. real-life German testing of WrkNr 14026, and there is perfect agreement between the shape of the German curves, and the altitude of 'break points'.

Well, not quite perfect.

The Soviet curve starts off convex at minimum supercharger speed, then goes on straight from maximum supercharger speed to full throttle height.

It should rather be a straight start followed by a concave drop off.

I consider the Soviet curve good enough, though :-)

Regards,

Henning (HoHun)

[gripen]

Dear Isegrim,
The subject of talking was about allied superiority in the high altitude engines. The Spitfire IX had been in service about two years when the Bf 109 with the AS engine reached service. At that time (spring 1944) the Spitfire XIV was allready in service as well as the P-51B with V-1650-3.

And you should also study how the supercharger of the DB 605 really worked.

HoHun,
Well, the question is open until someone comes out with more detailed data on the tests in Russia. If the testing organisation was as professional as you seem to believe, they should have known how the supercharger of the DB 605 worked. The Russians studied DB engines very carefully and  actually they tried to develop variable speed supercharger for the M-106 (or something, can't remember). I have one Russian report on the DB605, very accurate report indeed.

Otherwise it's very unlikely that a Bf 109G-2 could reach 670km/h at standard condition, certainly not at 1,3ata 2600rpm. Generally many German datasets are created without proper compressebility corrections (also the others had similar problems with corrections), the best known example of this problem are those high speed dive tests on a Bf 109F/G hybrid; mach number values and speed values in km/h do not match. In the Russian dataset sea level speed is in right ballpark assuming 1,42ata 2800rpm and wing cannons (if compared to FAF tests) but high altitude speeds seems to be  off; typical for correction errors.

gripen

[Angus]

I belive Gripen is very very accurate there, - from the introduction of the Spitfire Mk IX, the Spits enjoyed almost 2 years of "ceiling supremacy".
I have a nice story of this somewhere, will try to dig it up and type it in here.

Still, they are faster/better up there for a reason.
1) More Hp at that altitude
2) Lower wingloading and lower spanloading

I know of a case where a pilot pushed what he said was a Spitfire IX (it was from memory, could have been a Mk IIX) up to 49K. That was an armed operational aircraft. That should give some idea about the quality at that altitude

[Angus]

Oh, noticed a typo...
MK IIX is of course a Mk VIII......

[VO101_Isegrim]

Originally posted by gripen
Dear Isegrim,
The subject of talking was about allied superiority in the high altitude engines.

How did this superiority manifest? Certainly not in aircraft performance at altitude, we would have notice that.

The Spitfire IX had been in service about two years when the Bf 109 with the AS engine reached service.

The Spit IX entered service the same as the 109G. As was shown to you above, they had pretty much identical high altitude performance - in fact the 109G was somewhat faster, even without GM-1 equipment, which it also employed (and boosted speed at altitude by 120 km/h) You can debate this as long as you want.

Bottomline again, the Spit IX was not widespread until late 1943, but the 109G was a common fighter in the LW already in 1942.
I guess even you wouldn`t argue the Spitfire V was not really up with the Gustav, or even the Friedrich in terms of high altitude performance.

As for the engines themselves, the power curves clearly tell the Merlin 61 had somewhat better HA output than the DB 605A, but not by much. The much more common Merlin 66 was practically identical at HA to the DB 605A.

At that time (spring 1944) the Spitfire XIV was allready in service as well as the P-51B with V-1650-3.

And how many of them, Gripen? Spring `44, there were about 2-3 Squadrons just equipping with Mk XIVs, not yet even seen combat. Their number did not increase later on, the XIV remained a rare plane - with stellar high altitude performance. So as the RAF stood by late 1944 - 95% of their Spitfires were Mk IXs with clearly inferior altitude performance to the, again, very common /AS types.

And you should also study how the supercharger of the DB 605 really worked.

I guess I have very detailed reports on that, thank you.
You should perhaps start to think how ram effect works with the fixed ratio 1st speed of the DB s/c.

[HoHun]

Hi Gripen,

>If the testing organisation was as professional as you seem to believe, they should have known how the supercharger of the DB 605 worked.

Small inaccuracies like the concave/convex mixup can be found everywhere in the books. The entire RAE Spitfire data consists of simplified climb charts, for example.

I don't believe the Tsagi comparison charts were drawn by the same people who conducted and evaluated the original tests, anyway.

>the best known example of this problem are those high speed dive tests on a Bf 109F/G hybrid; mach number values and speed values in km/h do not match.

Do you have the data that doesn't seem to match? When I checked the figures from Radinger/Schick recently, I didn't find anything unusual about them.

Compressibility correction was standard operation procedure in flight tests. Germany was leading the world in high-speed research, I'd be very surprised if they didn't knew about that.

Regards,

Henning (HoHun)

[Siaf__csf]

The FAF pilots quoted the russian spitfires 'clumsy and slow at altitudes under 5000m over which the plane excells.'

The comparison was made to the brewster that was equipped with a standard airliner engine wo supercharger. It was adviced to get the spit and hurri into a turnfight where they were quote: 'helpless and easily killed.' This statement looks rather interesting if you compare the game performance.

Another quote: 'One mg burst in the forward section of a hurricane usually puts the plane in flames which consequently burned the pilot as the fuel tank was located between his legs.'

I've read several books and late interviews of FAF pilots who flew the G-2 without GM-1 and none of them has commented that the plane was either heavy or outclassed against the several types the soviets launched against them (P51, spit, hurri, airacobra, I-16, mig XX, LaGG xx just to name a few.)

[HoHun]

Hi Gripen,

>Otherwise it's very unlikely that a Bf 109G-2 could reach 670km/h at standard condition, certainly not at 1,3ata 2600rpm.

On the other hand, you might be right on the Russian tests.

It seems the Kennblatt quoted 649 km/h @ 7 km.

Regards,

Henning (HoHun)

[HoHun]

Hi Angus,

>I belive Gripen is very very accurate there, - from the introduction of the Spitfire Mk IX, the Spits enjoyed almost 2 years of "ceiling supremacy".

The initial production Spitfire IX (Merlin 61, +15 lbs) was indeed specialized for surprisingly high altitudes.

Since early Gustav performance is not finally agreed on, my personal estimate is that this Spitfire mark outran the Me 109G-2 above 8 km. The Spitfire also held the climb advantage there.

(This degree of specialization in my opinion makes it rather difficult to consider the Spitfire IX as the antidote for the Focke-Wulf. It was actually the antidote for the Me 109G! :-)

The later Spitfire IX (Merlin 66, +18 lbs) gave up that high altitude specialization in favour of better medium-altitude performance. This Spitfire was a pretty exact match for the Bf 109G-2 (1.3 ata, 2600 rpm), and suprisingly its area of superiority was at sea level! :-)

Spitfire and Me 109 are really an example for convergent evolution in my opinion.

Regards,

Henning (HoHun)

[HoHun]

Hi Siaf,

>I've read several books and late interviews of FAF pilots who flew the G-2 without GM-1 and none of them has commented that the plane was either heavy or outclassed against the several types the soviets launched against them (P51, spit, hurri, airacobra, I-16, mig XX, LaGG xx just to name a few.)

According to Geust, the Soviets agreed:

"The new Yak-1, Yak-7b and Yak-9 in production since beginning of 1943 and all lend-lease fighters delivered to USSR were considered to be inferior to the Bf-109G-2."

When the La-5FN finally appeared, it was reckoned to be the first fighter in Soviet service to be superior to the Bf 109G-2. (The earlier La-5 had been considered inferior above 3 km, and superior only at sea level.)

(Of course, you always have to be careful about tactical conclusions like these as they usually have a subjective perspective.)

Regards,

Henning (HoHun)

[gripen]

Dear Isegrim,
Well, so far you have shown nothing which can be verified from the accurate test data. The Spitfire IX with the Merlin 61 performed better than the Bf 109G-2 above 25k. This can be easily verified from for example FAF test data and A&AEE data. Note that high altitude Spitfires used also quite similar system as GM-1 (LOX or something).

HoHun,
Original report on those dive tests should  somewhere in the  net. (one of those Bf 109 sites, can't remember which).  Pressure calculation for the IAS does not contain compressebility correction. Actually one writer might release a study on this in the future.

The Bf 109G-2 should be able to reach about 640-650km/h at bit over 6,5km (early spec sheets say 7km but later ones say 6,6km, which seem to be quite accurate if compared to the test data) with 1,42ata and 2800rpm in the clean condition but that power setting was not used in the beginning. For the 1,3ata and 2600rpm the FAF data set on Bf 109G-2 is very good, actually you can check and calculate all the corrections by your self.

gripen

[MiloMorai]

Seriously, the particular page can be hardly considered to be anything more than a byproduct of being a Spit zealot`s 109-envy, in which the extreme bias and the smell of primitive little tricks can be smelled a mile away.

Nice description of yourself Barbi with the reversal of the Spit and 109.. You are the master of twisting facts, untruths and data manipulation/misrepresention.

Mk IX, MA 648. Same trick by Mike, another prototype, this type with a experiment with the SU fuel pump. 411 mph, WOW, not bad for a prototype that never saw any service

Another example by Barbi of fact manipulation for it was also stated:

"These results compare favorably with those of other Spitfire LF Mk. IX aircraft, which fact is attributed cheifly to the higher full throttle height obtained with the S.U. pump."


LOL, lets use that 4.2 you are so fond off. The 3 other Spits had higher top speeds. Conclusion, JL165 was an abnormality. JL165 was a re-engined Mk V manufactured 27.3.43 with tests done 8+ months later. One has to wonder at what the previous 8-10 months had done to the airframe?

No, I wonder, why this classy selection misses good old JL 165, a 'standard Spitfire Mk IX LF' to qoute it`s perfomance trials, that managed to do... uhm... 388 mph.

Since the Spits were in the 2cd TAF, its opponents would not be the higher altitude 109s. B-17s, B-24s, P-38s, P-47s and P-51s were their opponents.

So as the RAF stood by late 1944 - 95% of their Spitfires were Mk IXs with clearly inferior altitude performance to the, again, very common /AS types.

For Reich and NW Europe.(Source: Alfred Price's Luftwaffe Data Book)

How many of the 342 flyable 109 were /AS types?(as of 31.5.44)

How many of the 446 flyable 109 were /AS types? (as of 10.1.45)


Nice to see HoHun, a rational discussion without the bigoted zealotness the 'brown shirted' Barbi shows.

[Angus]

A question for you all, regardless of speeds.
Would you think that a Spitfire (From Mk I to IX) would be able to invert the plane in the final approach, lower the gear while inverted, then roll onwards untill level and  very quickly settle to a three-point landing?

It is possible in AH. I am wondering about the roll rates, and the stalling characteristics...

[Staga]

Gripen;

Guess Finnish Bf109G-2's were having some strange powerups 'cause they achieved 640kmh with boost limited to 1,3ATA.
Aircrafts were dressed for battle (full fuel + ammo + radios, whole show).

http://www.kolumbus.fi/staga/scans/MT215_speed.jpg