On Soviet turning time tests. Comments Please

[VG-33]

Originally Posted by Soren .
Odd with the results though, considering the very poor results achieved in the Soviet tests.
Just goes to show that these tests are infact very unreliable, just like I've pointed out a multitude of times by now.

Why do you think that soviet or other tests are inreliable?

The tests are probaly much more reliable, if conducted over time by professional test pilots - than the aero models presented in these forums as the last word in turn modelling as I have noted multiple times also..

Thank you. It's time to have a look at those famous soviet tests.

1) it looks like that the Mustang was not on it's best health, and from memory it was tested at 3740kg.
2) operationnal P-40 and P-39 never exceed 3300/3500kg in units, were they were relieved from extra equippements, extra guns, extra armor plates, extra fuel. So i don't see the reason why should the fly at 3800 kg for the tests.
3) Soviets recognised the exceptionnaly small Cd of the Mustang, but also have found that it was too big and too heavy for it's engine. Just like Hurricane, P-40, and partially the P-39.
4) 90% of the airfights took place in the eastern front under 4000m. Soviets knew about the P-47 and P-51B/C, that they were altitude fighters (by eastern standards) and never provide any interest for them. 198 P-47 joined the USSR, none of them was used in operations, AFAIK.

Regards

 

[Kurfürst]

109 Weights, for clean aircraft, at full take off load (ammo, fuel, pilot etc.)

F-4: 2890 kg (probably without stuff added later, like dural armor, windscreen armor)

G-2: 3037 kg

G-6: ca. 3100 kg

G-6/trop: 3150 kg

G-10 / U4
Weight : 3343 kg

G-10
Weight : 3297 kg

G-14
Weight : 3247 kg

G-14 / U4
Weight : 3318 kg

G-14/ASM
Weight : 3272 kg

K-4
Weight: 3362 kg

Soviet G-2 used 1.3ata, not 1.42, lower or higher turn figures are for turning in left or right.

The Soviet turn times are waaaaaay higher for the 109E, looking at the climb curves (which show an extreme fallback in rate of climb towards sea level, but pretty normal above that), I suspect something was not kosher with the 1st supercharger speed... the figures are BTW not compatible with British estimates (no turn time tests were done, figures were extrapolated from Spit's measured Cl) , the Russian ones were for 1000m, the British ones were for 12k feet (~4000m). German specs give 18.92 sec for a sustained turn at SL for the Emil, at 5 min rating, w/o using the 1-min special low-alt augmented rating.

 

[Soren]

J'm not a Me-109 specialist.
Can you explain us why G-10 was just as heavy as the G-2 since he was carrying 70 kg (?) MW system (pump, ducts, valves), 70 (?) kg empty bottle and 70 kg (?) chemicals?

Or am-i wrong? It's just a question...

VG you obviously have some kind of agenda so I'm not going to discuss this with you.

 

[Soren]

109 Weights, for clean aircraft, at full take off load (ammo, fuel, pilot etc.)

F-4: 2890 kg (probably without stuff added later, like dural armor, windscreen armor)

G-2: 3037 kg

G-6: ca. 3100 kg

G-6/trop: 3150 kg

G-10 / U4
Weight : 3343 kg

G-10
Weight : 3297 kg

G-14
Weight : 3247 kg

G-14 / U4
Weight : 3318 kg

G-14/ASM
Weight : 3272 kg

K-4
Weight: 3362 kg

Soviet G-2 used 1.3ata, not 1.42, lower or higher turn figures are for turning in left or right.

Thanks Kurfurst, that solves some of the issues. The G-2 would've no doubt done just as well as the F-4 if run at 1.42 ata, that's 19.6 secs. Again reasonable. With 400 to 525 more hp the G-10 K-4 would've no doubt been around 19.3 to 18.8 sec respectively.

Again thanks for the info Kurfurst, a pleasure to have you around

 

[claidemore]

As far as weights for the 109F4 and G2,and G14 I agree.

For the G6 I have a climb chart for a G6 Trop that listed it as 3250 kg and there is a chart on Kurfursts site, here: Kurfrst - Flugleistungen Me 109G - Baureihen
,that shows the G6 at 3350. The Finnish manual shows the G6 at 3500 kg, 3800 with wing cannon. I'd be interested in seeing which documents show the G6 at 3100 and 3150 kgs.

G10 afaik should weigh pr3etty much the same as the K4, 3400 kg (weight varied depending on which tail unit the plane had according to Erich Hartmann). There are multiple climb and level speed charts for the K4 that show 3400 kg. Maybe there are other docs that show 3364 or 3362.

In any case, subsequent models of the Gustav were definately heavier than the G2, as we have all been told since we first started reading about warbirds. Whether or not the additional horsepower made up for the weight increase during combat turns is debatable. It doesn't seem to have helped the G2 turn better than the F4.

 

[Juha]

Soren
Look the tread, I and m kenny asked several times your sources on Kursk losses, I asked they once even in the Best truck or something like that tread, again no answer.So I asked you many times. And I agree that Germans lost far fewer tanks and StuGs in Kursk than Soviets.
OK I'm complete ready to leave this subject behind and move forward.

Juha

 

[Juha]

My info agreed with Kurfürst's info on those version's I recall, I checked my table of 109 specks yesterday morning and G-2, G-10 and K-4 were same.
Kurfûrst thanks a lot fo posting the complete list and the info on 109E tests.

Hello Claidemore
IMHO the Finnish weights are for max T/O weights so they are higher. IIRC one German docu on tyres used in 109s gave max T/O for G-2 3300kg and for G-6 3650kg, I cannot recall the weight for G-6/R6 with droptank. Kurfürst weight are for clean a/c as he wrote.

Juha

ADDUM

Hello Kurfûrst
A couple of questions
If Soviet tests were at 1.3 ata they were exceptionally fast, especially the G-2/R6, German normal speed for the version at 1,3 ata was 636km/h at 6600m, so 660km/h at 7000m for a plane not fresh from factory was rather spectacular. Even the 666km/h for clean G-2 was a bit higher than any of the 13 tested production G-2s from Erla achieved in April43, thanks for this info from your site. One at least partial explanation is of course that the German figures are compression corrected and Soviet are not.

In your site in the table of various early versions Gs with different installations G-6/R6 is 90kg heavier than G-2/R6. Can you comment that?

And fetched my 109 spec table from my attic,
And yes, G-2 and K-4 weights are same than those in Kurfürst's list, my G-10 weight is the same than that for G-10/U4 in Kurfürst list, probably K's figure is correct.

But the figure for G-6 is 3196kg
A couple weights for versions not in Kurfürst list, I'd appreciate, if Kurfüst would comment these.
109G-6/U3 3320kg(R2), I know this wasn't an official designation but it gives info on what was installed in the a/c.
109G-6/AS 3221kg.

And the tyre table
Max allowed T/O for G-2 3400/3500kg depending on tyre type and normal 3200/3300kg.
For G3-G6 max 3650kg, normal 3500kg. But IMHO these weights are for different purpose than weights above or in K's list, IMHO this info only highlighted that a/c weight is a complex question and we can find documented but conflicting info on subject.

 

[Juha]

BTW, GL/C-E2 FLUGZEUG-ENTWICKLUNGS-BLATT Bf 109 (J) 20.8.1944 gives the T/O weight of Bf 109G-6 as 3,2 metric tons.

Juha

 

[drgondog]

Why do you think that soviet or other tests are inreliable?



Thank you. It's time to have a look at those famous soviet tests.

1) it looks like that the Mustang was not on it's best health, and from memory it was tested at 3740kg.
2) operationnal P-40 and P-39 never exceed 3300/3500kg in units, were they were relieved from extra equippements, extra guns, extra armor plates, extra fuel. So i don't see the reason why should the fly at 3800 kg for the tests.
3) Soviets recognised the exceptionnaly small Cd of the Mustang, but also have found that it was too big and too heavy for it's engine. Just like Hurricane, P-40, and partially the P-39.
4) 90% of the airfights took place in the eastern front under 4000m. Soviets knew about the P-47 and P-51B/C, that they were altitude fighters (by eastern standards) and never provide any interest for them. 198 P-47 joined the USSR, none of them was used in operations, AFAIK.

Regards

VG - the Allison V-1710 references shows it was clearly a Mark I (NA-73)
.. The curious question is why a Mustang I only while the P-47D-10 came into the 8th AF in (IIRC) in late 1943. Maybe the USSR never tested the Mustang III-IV.

BTW - Thanks for the turn test data - I was suprised at even 60%. What is the CLmax of that wing and are any flaps deployed, etc to maintain that CL at those bank angles

 

[Juha]

Hello Drgondog
SU got 196 P-47D and 7 were lost during delivery, 3 D-10, 100 D-22 and 100 D-27.
On Mustangs
SU got from UK 4 or 10 Mustang Mk Is, that's why it was the tested version.
On later models, SU restored to airworthy conditions some left behind during Frantic ops. And some others found during advance to West. According to Gordon's and Komissarov's US A/C in the SU and Russia p.141. Several P-51Ds were subjected to a limited amount of flight testing. "Test pilots noted again the Mustang's easy handling. As performance comparisons, the P-51D was found to be inferior to Soviet fighters in climb and horizontal manoeuvrability at low and medium altitudes. Conversely, at altitudes above 5000m the P-51D was clearly superior to Soviet fighters, as well as to the German Bf 109K."

Juha

 

[VG-33]

VG - the Allison V-1710 references shows it was clearly a P-51A..

It was. Tested in NII from april to june 1942

The curious question is why a Mustang I only while the P-47D-10 came into the 8th AF in (IIRC) in late 1943. .

The P-47D-10 R-2800-63 was tested from april to june 1944. Some sources are quoting 26s ToT. Maybe at different weights. Soviet data: usual 6000kg, max 6780 kg.

Maybe the USSR never tested the Mustang III-IV

Some soviet test pilots ( Gallaï, Taroshine, Stepanenko...) flew P-51D during shuttle raids, not in official trials. No report was found about that, only numerous memors...

BTW - Thanks for the turn test data - I was suprised at even 60%. What is the CLmax of that wing and are any flaps deployed, etc to maintain that CL at those bank angles

No problem. For 73,8%, n(y) = 3.6g; n(z) = 1; n(t) = 3.736


n(t).m.g = 1/2 .(rhô) .V².S.Cz

Cz*= 2mg/(rhô) V²S

Cz = 2 x 3.73 x 1700 x 9.81 / ( 0.971x 1.225) ** x 70² x 22.15

Cz = 124 410,4 / 131 139,5

Cz = 0.95***


*I'm French, i use metric system ; Cz = CL in american

** at 1000m altitude

*** Why don't you try to do it with Soviet P-51A for fun, since i gave you all datas on P-40 vs Me-109 treat?


Moreover, from the same scientist work (Pyschnov) it was found that due to it's partition of gull wings the fuselage side had in fact 3,5-4 L/D ratio, and was giving more than 2000 kgf (19 700N) side lift. Unfortunately no speed indicates: between cruise and max speed i suppose...
That mean if inclinating its fuselage, the pilot was able adding some lift (5-10 000 N ? on vertical axis) to the previous figure making plane either to climb on the same ToT, either to reduce apparent loading n (t) and making the ToT and radius even more better, flying on that modified asymetrical position!

Best Regards

VG 33

 

[VG-33]

Thank you Kurfurst

Soviet G-2 used 1.3ata, not 1.42, lower or higher turn figures are for turning in left or right.

Fine! Can you show us soviet original test reports?

The Soviet turn times are waaaaaay higher for the 109E, looking at the climb curves (which show an extreme fallback in rate of climb towards sea level, but pretty normal above that), I suspect something was not kosher with the 1st supercharger speed...

It seems that soviets have baught 5 Bf 109E, but recieved only 3. Do you mean all of them had kosher problems?

German specs give 18.92 sec for a sustained turn at SL for the Emil, at 5 min rating, w/o using the 1-min special low-alt augmented rating.

Have you got german specs for the other planes, please?

VG-33

 

[VG-33]

Now regarding the Clmax of the P-51, I would agree on ~1.5, eventhough I remember NACA saying 1.35 (Report 829). By comparison the Spitfire's was 1.36, Bf-109F/G/K was 1.7 and FW-190's was 1.61. All three a/c also have lower landing stall speeds, the Spitfire Bf-109 considerably so, and the Fw-190 being very close and pretty much the same as the P-51.

So my assessment has largely derived from the standpoint of lift generated vs the weight of the aircraft plus the amount of power available.

.

Your assessments will be less ridiculous the day you would use realistic Cl values.

So on ToT(mini):

P-51's Cl = 1.095

Spit's Cl = 1.08- 1.14

Me 109 G2 Cl = 1.1-1.15

FW 190 Cl = 1.44



I complete soviet ToT for 1943


Plane: Yak-9, La-5FN, Bf 109G-2, FW190A-4

weight: 2873, 3158, 3023, 3989

speed at SL: 520, 562/595*, 524, 510
speed at heigh: 599, 648, 666, 610

Power: 1180, 1700/1850, 1475, 1730
Wing aera: 17,15, 17,56, 16,20, 17,70

Time to 5000 m, мин 5,1, 4,7/_*, 4,4, 6,8
Tot at 1000м, 17-18, 18-19/_*, 20,8, 22-23

But, unfortunatly for soviets serial La-5/La-5FN were havier, loosing about 1s on ToT.
So the best turners in 1943, in europe and maybe off the world were lightened Yak-1 series:
16-17s for 2780kg weight

Regards

 

[Soren]

Sorry but you're the one using ridiculous Clmax figures VG-33, not me.

Or are you to suggest that you know more than the guys at the National Advisory Committee for Aeronautics??

Also I suggest you leave this argument until you start accepting the reality of things.

 

[VG-33]

Sorry but you're the one using ridiculous Clmax figures VG-33, not me.

.

Who said that it was CLmax figures? CLmax aren't of any kind of interst here since, we speak about real Cl used on minimal time of turn (during flight tests or in the reality of things using your proper worlds).

So on ToT(mini):

as i wrote

 

[Kurfürst]

If Soviet tests were at 1.3 ata they were exceptionally fast, especially the G-2/R6, German normal speed for the version at 1,3 ata was 636km/h at 6600m, so 660km/h at 7000m for a plane not fresh from factory was rather spectacular. Even the 666km/h for clean G-2 was a bit higher than any of the 13 tested production G-2s from Erla achieved in April43, thanks for this info from your site. One at least partial explanation is of course that the German figures are compression corrected and Soviet are not.

If you take a look at the Erla figures, there is a thick line showing the official specs for the 109G - 660 km/h at 7000m @ 1.3ata, with +/- 3% tolerance. This is also what the early datasheet, Datenblatt IV/42/42 from May 1942 shows. The avarage of the tested, accepted aircraft (3 aircraft did not meet tolerance requirements) shown was IIRC 652 km/h, but take note the Erla specs refer to the coolant radiator flaps being 120mm open - the standard was 50mm open, so the get comparable specs, add about 10 km/h (see Leistungzusammenstellung 109G from Jan 1944) to get comparable figures.

Soviet figures were 666 km/h at 7000m, so I don't think there was exceptional about the plane, it was probably in fairly good condition, and it was pretty close to the offical specs. Moreover if you do an overlay of climb figures with the Finnish tested G-2 MT 215, the figures are almost a complete match, 'cept for low altitudes where the Finnish test shows higher figures, but this can be explained by the fact that the Finnish trials were done at higher climb speed and the radiator flaps opened at only about 2000m (above which the figures are pretty much the same with Soviet trials).

In your site in the table of various early versions Gs with different installations G-6/R6 is 90kg heavier than G-2/R6. Can you comment that?

But the figure for G-6 is 3196kg

I have no idea why the first table shows different figures. I have several weight and loading tables for the G series, and it has to be said that even German tables are somewhat chaotic, or just outright sloppy.

Weight given for the G-2 w. Rüstsatz VI (gondola cannons) is 3260 kg, for the G-2 w. Rüstsatz VI is 3350 kg. The gondalas, incl. ammo, weighted 215 kg, so that would give 3045 kg for clean G-2 and 3135 kg for clean G-6.

I am puzzled why the later GLC datasheets give 3196 kg for the fighter G-6, though I can speculate that some additional radio navigation system was added. For example the G-6/trop Ladeplan gives 3154 kg as take off weight, and as per butch2k, the /trop version was some 50 kg heavier because of extra equipment (sand filter, survival kit etc.). The addendum to the GLC datasheets from 1944 on the other hand gives "Startgewicht - 3,1 t" for G-6.

Though I am pretty sure the weight of the early G-6 was around 3.1 tons. The MG 131s added +40 kg (see LZStg 109G), the other weight difference should come from increased tyre size and the FuG 16 and FuG 25, but I can picture these adding to 3196kg.

A couple weights for versions not in Kurfürst list, I'd appreciate, if Kurfüst would comment these.
109G-6/U3 3320kg(R2), I know this wasn't an official designation but it gives info on what was installed in the a/c.

Its a fighter-recce version with MW 50 system and cameras.

 

[Juha]

Hello Kurfürst
Thanks for answering. One must be careful not to place unduly reliance to Finnish climb tests, the warning in the original test reports says that climbtest results were somewhat inaccurate because flight test instruments were not installed.

Quote:" it has to be said that even German tables are somewhat chaotic…"

Yes, I have noticed that also, but it is true also to at least some countries a/c info, different a/c of exactly same type tended to give a bit different test results and weight increase during the service was also very common.

Quote:" Its a fighter-recce version with MW 50 system and cameras."

Yes, I know that. I was asking your opinion on its weight, sounds it reasonable? To me its OK, G-14 weight plus camera installation weight gives almost the same as it IMHO should.

Juha

 

[Juha]

Hello VG-33
Thanks for the engine power info in your message #73.

Juha

 

[VG-33]

Hello Juha

Hello VG-33
Thanks for the engine power info in your message #73.

Juha

The turn trials were made at 1000m as usual for soviet tests.
1180; 1700/1850*; 1475; 1730 are sea level power values.

At 1000m it should be ~ 1240 for the 105PF and 1750 at nom for the 82FN, 1900 at 10-20 min combat power* for test conditions...

It's also possible that soviet 109G-2 ran at 1.42 ata boost for max speed an 1.3 for climb and turn. Anyway on soviet sources for engines (Samoletostroenie, TsAGI edition 1994) both power curves are indicated on draw.

I confess that soviet 109E-3 used 1.26 ata on ToT for the datas i gave.
But 1.33 boost was also used for climb ans turn, with better results of course.

Regards

* very strange question in fact, since the same engine used in La-5F had no time limitation only cylinders and oil heat. La 5 FN flight manual shaws limitation but it was send to units a year later. In fact, nobody had never respected intake pressure limits on all La-5/7, only temperature...

Cf Alexeiev on airforce.ru. And Valoucek interviews in mid-70ies.

 

[Juha]

Hello VG-33
thanks for the extra info.

Juha