On Soviet turning time tests. Comments Please

[VG-33]

The weight of the K-4 was 3,364 kg, and the weight of the Bf-109G-10 was 3,148 kg IIRC. Which is abit heavier than the 3,050 kg of the G-2, that's true.

Was it with the MW-50 injection system, or without?

Anyway a 18.8 sec turn time for the K-4 seems very reasonable for a 525 hp increase in power while weight increased only by 286 kg.

Might be, but how do you obtain your results. Can you show us used formulas and calculations?

Regards

 

[VG-33]

Like I've said before I'd take the Soviet data above with a large handful salt. But that's just my advice to you guys, you are free to believe in what you want ofcourse. I will however note that the Hurricance was in general considered a better turnfighter than both the Spitfire Bf-109.

If you want to know the true turn performance of these fighter aircraft then I suggest you take a look at the physics, in my experience it never lies, ever.

Ok, but what physics are saying about Hurricane's turn radius and Time of Turn?

Regards,
VG-33

 

[VG-33]

Hello
I updated my list according to the new info provided by VG-33 and Claidemore.
Many thanks to Claidemore and specially to VG-33
Juha

Soviet turning time tests



Hello Juha, j'm not sure that a new info should systematicly replace the older one. I think it would be better to build a full database on different sources, since we don't have access to original NII reports. And if there would be differences (and they are..), let's see the reason (type mismatch, different test condition etc...)

So I will share with pleasure my Shavrov's database
Year- Plane- Power- Lengh- Wingspan- wing Aera -Empty equipped weight- oil -full load-Take Of weight- Wing load- Po/We ratio-TO/empty Weight ratio-Ceiling-endurance-range- time of turn- take off-landing-max SL speed-max speed-landing speed- time to 1km- T to 3km -T to 5km- T to 7km - To 9km

1933 И- 15 (ЦК.Б) «Райт-Циклон» Ф-3 630 715 6,1 9,7 14,0 +7,9 965 177 409 1374 62,8 2,18 30 9800 2,6 500 8,3 4(70) 6(70) 318 368 90 1,1 3,4 6,2 11 24 .

1933 И- 15с М-22 480 6,1 9,7 21,9 1106 177 409 1415 7520 8—8,5 4(70) 6(70) 286 350 90 5,6 11

1934 И-15 (ЦКБ-3 бис)с М-25 630 715 6,1 9,7 21,9 960 177 409 1369 62,6 1,92 30 9800 2,6 550 8—8,5 315 367 90 1,1 3,3 6,1

1937 И-15бис (И- 152) сс М-25В 750 6,2 10,2 22,5 1310 420 1730 77 2,3 24,3 9000 2,6 530 10,5 9 (170) 15 (237) 321 370 6,7 28

It's data for Polikarpov I-15 experimental, I-15serial, I-15bis exp, I-15bis serial

Regards

 

[Juha]

Hello VG-33
thanks a lot for the new info.

BTW
the P-39 without info on subtype, 19 sec. I wonder if it is after all D-2 with wing armament, bacause we have P-39D-2 (with wing armament) - 17,7-18,7 sec and P-39Q-15, without gunpods.- 20-21sec. The higher end of D-2 turntime, 18,7sec, is pretty close to 19sec and if turntime of Q-15 is that, it was 94lbs lighter than D-2 even with gunpods, so probably the Q-15 was using 95 oct and 1200hp, not 100oct and 1420hp. Pure guesswork from my part, I know but otherwise the table looks rather consistent and in agreement with Finnish observations but the info on LaGG-3 series 28, but of course the quality of LaGGs varied. And of course Finns did not have own info on Mustang Mk I, Bf 109F-4 and Fw 190A-4.

Juha

 

[Soren]

I didn't forget about any weight growth really, not any appreciable one at least, and less so than I understated the weight growth of the Spitfire IX over the Mk.V, but you ofcourse chose to overlook that. So frankly I think you're the biased one here Juha, not me.

The aerodyamic improvements on the K-4 included the wheel well covers, front and back. And this alone had the cruising speed rise a lot. So if you're implying that it made no difference because of the wing bulges engine cover bulges, well then you couldn't be more wrong. The wing bulges added very little drag, as did the engine cover bulges.

 

[Soren]

Here is the USAAF tests of P-51A versus P-40F and P-39D

P-51 Tactical Trials

The operative phrase is none of these tested had an appreciable advantage over the other in turn performance..

Ah a P-51A, I was talking about the B, C D Bill.

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.

 

[Juha]

Soren
I don't complain on your Spit analyze, but how it happened that when you talked on P-51 you only mentioned wieght growht, not a word of some 400hp (for B/C) power rise and for 109 you mentioned only power rise and wrongly claimed that G-10 with MW50 system and all was as light as G-2? And remember that those G-2s Soviet used in their tests had semi-rectable tailwheels not the fixed ones. And BTW the extra underwing antenna, direction finder loop, deeper oil cooler, of course they generated no extra drag?

Juha

 

[Juha]

Hello VG-33
Didn't notice your follow-up question on the slots on LG-1, I own copies of a couple books in which there are photos in which the slots show up but no scanner.

But lets try, there was a row of 5 narrow slots side by side in each wing, the outermost hinge of aileron was more or less in line with the narrow gap between the outermost slot and the next slot inwards. Not very scientific but I tried to figure out this from a photo, not from drawings, if I find better info I'll post it.

Juha

 

[Soren]

No ofcourse you didn't have aproblem with my Spit analysis, cause I actually spoke in its favour. Yet somehow when'ever I say something good about something German you get all upset. Why is that ?

As for the P-51, all I ever said was I was interested in how the later versions would've done in the Soviet tests considering they didn't get any lighter. You somehow twisted that into me saying it should've done worse, I never said this.

You keep calling me biased and you trying to insult me with your snide remarks nomatter what I say, be it in favour of something Allied or Axis, and again my question is why ? Don't you realize it just makes you come across like a jerk ?

There's a reason I've been ignoring you for so long. Now I've decided to be kind and give it another chance. But if you continue your childish ways with snide remarks and accusations then I see no option but to just keep ignoring you.

 

[drgondog]

Ah a P-51A, I was talking about the B, C D Bill.

Odd with the results though, considering the very poor results achieved in the Soviet tests.

The published soviet tests had the P-40 and P-39 in sub 20's. The 51B/C/D with the extra Hp should compare well with those same ships despite a 200 pound growth in weight from P-51A to P-51B (w/o 85 gallon fuselage tank)

Just goes to show that these tests are infact very unreliable, just like I've pointed out a multitude of times by now.

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.

Neither Henning's or Davidson's excel models properly account for Cd0 changes from high speed/RN through the velocity reduction phase. Parasite drag is NOT a constant in such models... and it is only one of the variables that change with high AoA and velocity degradation.

 

[Soren]

Well all esle being equal a higher lift to weight ratio should mean a better turn performance Bill, that's all I'm saying here.

Let's also not forget that the P-51's wing wasn't so well suited for turn fighting, the laminar type airfoil would limit the Clmax as it was lower than that of ordinary airfoils. Drag was however ofcourse much lower in straight flight.

But to no surprise I'd expect the Bf-109 to perform a good deal better than the P-51 when it comes to turn performance, atleast at low to medium altitude. I'd expect the Fw-190 to only do a little better or similar at the same alts. But at high altitude the P-51 was however in its element, having a lot more power available than most 109's 190s, and I highly suspect that the P-51 would turn with most a/c at high alt.

Also regarding the US tests, maybe they were carried out at high alt. The Soviets however, being used to only flying at low alt, would've probably done their tests at low alt.

Just my thoughts.

Anyway low speed turn performance had so very little importance by mid 42 that it is largely to be ignored in most circumstances, esp. considering that all a/c in question would be capable of unsustainable amounts of G's at speeds as low as 350 km/h. And the P-51 did sport great controllability = maneuverability at high speeds, which is what matters. The Fw-190 was considered a better dogfighter than the 109 by some LW vets for the same reason, it was much easier to maneuver at high speeds.

 

[VG-33]

Hello VG-33
Didn't notice your follow-up question on the slots on LG-1, I own copies of a couple books in which there are photos in which the slots show up but no scanner.

But lets try, there was a row of 5 narrow slots side by side in each wing, the outermost hinge of aileron was more or less in line with the narrow gap between the outermost slot and the next slot inwards. Not very scientific but I tried to figure out this from a photo, not from drawings, if I find better info I'll post it.

Juha

God! SLOTS, not SLATS!

Sorry Juha for my english, i called them wing fences !

In fact all first LaGG series had slots, until the 1941th late summer early automn, when the feature was released in order to increase production numbers. They were also lighter because they used delta-drevesina instead ordinary wood for spars and some other strucural details. It's the reason why they were also much better turners than the latter ones. Until the 23 th series planes equipped with wing slats.

I'v got detailed LG-1 photos, in fact, from Fana de l'aviation and In action magazines.
Thank you

Best regards,

VG 33

 

[VG-33]

Well,

Browsing the web and considering it's not that difficult to find some general and performance data for soviet/russian plane (airwar.ru, airpages.ru, wiki...) i decided to make it clear and keep only ToT as Juha already did. Of course wing loading, power ratio might be useful...but also simply deduced from other data.

So

Polikarpov I 15 experimental : 8.3
Polikarpov I 15 serial: 8 - 8.5

Polikarpov I-15bis e: 8—8,5
Polikarpov I-15bis s: 10,5

Polikarpov I-153s/ M25V: 11,4-12,4
Polikarpov I-153s with BS/ M62: 11,4-12,4
Polikarpov I-153s with GK/ M63: 14
And finish tests from Juha have good reliability since they are correlating with soviet NII-VVS trials and also with studies from prof Pyshnov on I-153 ToT

But there is a little bug in the image corrected in the book's text:
Instead of 12 s at 65 m/s, read 11s
12s at 60 and at 68m/s too.

Considering 110m radius on Finish tests for 12s, they are exactly at 60m/s point .

Congratulations guys!

For Drgong

I would have to see some serious wind tunnel data to believe that it could maintain and sustain altitude in even a 60 degree bank angle

As you can see in that study we have acceleration n(y)> (or more than 60°) 2 from 45 to 100m/s.
The higher value is 3.6-3.7g so it's around 73 - 75°.

 

[VG-33]

Hello VG-33
thanks a lot for the new info.

BTW
the P-39 without info on subtype, 19 sec. I wonder if it is after all D-2 with wing armament, bacause we have P-39D-2 (with wing armament) - 17,7-18,7 sec and P-39Q-15, without gunpods.- 20-21sec. The higher end of D-2 turntime,
Juha

Just a mention, 17,7-18,7 it's not a range of probablities or uncertainlies, just Right Turn/Left turn values. Anyway for obvious reasons it's difficult to measure ToT's with some accuracy.



Regards

VG

 

[drgondog]

Well all esle being equal a higher lift to weight ratio should mean a better turn performance Bill, that's all I'm saying here.

lower wing loading is an important factor - but not the only important factore. Total wing body parasite drag is huge in energy retention

Let's also not forget that the P-51's wing wasn't so well suited for turn fighting, the laminar type airfoil would limit the Clmax as it was lower than that of ordinary airfoils. Drag was however ofcourse much lower in straight flight.

Drag was lower in all flight regimes. The CLmax was an honest ~1.5 at high AoA. What is not well known is what the CLmax values are for any of the aircraft we are debating while in a high AoA and steep bank angel.

But to no surprise I'd expect the Bf-109 to perform a good deal better than the P-51 when it comes to turn performance, atleast at low to medium altitude. I'd expect the Fw-190 to only do a little better or similar at the same alts. But at high altitude the P-51 was however in its element, having a lot more power available than most 109's 190s, and I highly suspect that the P-51 would turn with most a/c at high alt.

Also regarding the US tests, maybe they were carried out at high alt. The Soviets however, being used to only flying at low alt, would've probably done their tests at low alt.

Two of the USAAF comparisons and several USN comparisons were made at low, medium and medium high altitudes so the flight tests were made for a variety of combat conditions - which made sense as USAAF was fighting against Zeros at medium altitudes, 109s/190s at all altitudes

Just my thoughts.

Anyway low speed turn performance had so very little importance by mid 42 that it is largely to be ignored in most circumstances, esp. considering that all a/c in question would be capable of unsustainable amounts of G's at speeds as low as 350 km/h. And the P-51 did sport great controllability = maneuverability at high speeds, which is what matters. The Fw-190 was considered a better dogfighter than the 109 by some LW vets for the same reason, it was much easier to maneuver at high speeds.

Soren - so much of our arguments either reduce to 'piece by piece' individual data, questions regarding pilot familiarity of tested enemy aircraft and metrics derived from incomplete excel spreadsheet models.

I'm quite comfortable assessing the Mustang, Spit, Fw 190 and Me 109 as near equivalent single engine fighters throughout the war in their different stages of development - particularly after mid 1943.

Each had advantages, some more than others depending on the encounter circumstances - so the outcome was oftern factored by pilot skill primarily.

 

[Juha]

Hello Soren
Quote:" No ofcourse you didn't have aproblem with my Spit analysis, cause I actually spoke in its favour."
Now, IMHO you gave more or less right info, so I didn't have anything against it, I only noted that Spit F IX was a bit more heavier in comparison to Mk VB and in West later on Spit IXs had more power but you guess on power gain was about the same that I thought when we think the Soviet tests.

Quote:" Yet somehow when'ever I say something good about something German you get all upset. Why is that ?"

I'm here mostly to learn more, so any new piece of info is valuable to me What put me off in many of your messages is
a) tone which I think is sometimes propagandist, for ex from Bf-109 vs P-40 tread
Quote:" The La-5 has very small span slats …The Bf-109 is entirely different with long span slats…"
Now because slats of La-5 covered ca. 38% of span and those of Bf 109G a bit over 40% IMHO your tone was propagandist.
b) When you gave erroneous info you usually, when asked for your sources, first gave some evasive answers, look for ex. "Tank commanders, who was best?" –tread after your message #21, in which you gave clearly too low German loss figure (a bit under1/3 of the real one) and then only partial answer Kirosheev others. Which was in fact not really an answer, because we, who know something on Kursk know that modern Soviet loss figures come from Soviet docus, usually via Kirosheev's book and what was odd in your figures was the German loss figure. Further inquiries of your sources got no answer. What logical conclusion one should made from the fact that one didn't answer when asked where he had got his wrong figures? Or you simple disappeared from the thread without any answer. I can give an example on that also if you insist.

You asked and I answered.

Juha

 

[Juha]

Hello VG-33
again thanks a lot for the data and explanation.

Juha

 

[Soren]

There you go again Juha, you simply can't write a post without having to include some sort of insult. Drop it Juha, it really doesn't help you.

Regarding Kursk and German losses there, I truly can't even remember that argument. I remember an argument about the overall losses of WW2 where I spoke of Kirosheev, that's it. And then regarding Kursk, well the Germans did loose a lot less than the Soviets, and that's fact, you can read about anywhere nearly, but unlike the Soviets the Germans couldn't replace what they lost, again fact. So that is atleast something I know. Now if you feel you know more than me without having even asked me then be my guest, its not like I care really, I'm here to learn and help others where I can.

 

[Soren]

[QUOTE="drgondog]Drag was lower in all flight regimes. The CLmax was an honest ~1.5 at high AoA. What is not well known is what the CLmax values are for any of the aircraft we are debating while in a high AoA and steep bank angel.[/QUOTE]

Ofcourse, as the lower the lift the lower the drag, as we both know they have a very close relation to each other.

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.

But now we're again just talking turning, speed, climb rate, controllability at various speeds etc etc are even more important.

 

[VG-33]

The Bf-109G10 was just as heavy as the G-2, yet it featured over 400 more horsepower, now that would yield atleast a 1 sec improvement if you ask me.


Now I must admit that actually does make sense.

J'm not a Me-109 specialist.
Can you explain us why G-10 was just as heavy as the G-2 since it 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...