Spitfire XIV vs Bf-109 K-4 vs La-7 vs Yak-3

[ponsford]

Numbers don’t reflect on performance in my opinion and this shouldn’t be held against LW aircraft. Alfred Price cites April 45 figures of Luftwaffe serviceability showing JG 26 and 27 could muster a little over 100 Fw 190s and Bf109s between them, which was less than either the Spitfire XIVs or Tempests facing them in NW Germany. Most all the other LW units were facing the Russians or 9th AF in south west Germany. I remember seeing a German document of serviceability for April 45, I forget where (maybe here), but it was similar to Price’s data.

[Kurfürst]

Spitfire XIV (all types) production per month, originally compiled by milian:

First number production in that month, second number cumulative production by the end of the month.

Total Delivered by end of month - Number delivered that month

1943 : 18 18

01-44 : 30 12
02-44 : 45 15
03-44 : 50 05
04-44 : 56 06
05-44 : 68 12
06-44 : 101 33
07-44 : 129 28
08-44 : 151 22
09-44 : 185 34
10-44 : 245 60
11-44 : 300 55
12-44 : 341 41

01-45 : 399 58
02-45 : 511 112
03-45 : 648 137
04-45 : 743 95
05-45 : 815 72
06-45 : 844 29
07-45 : 873 29
08-45 : 891 18
09-45 : 898 7
10-45 : 904 6
11-45 : 911 7


Bf 109K production

09-44 : 15 15
10-44 : 293 308
11-44 : 221 529
12-44 : 325 854

01-45 : 338 1192
02-45 : 233 1425
03-45 : 168 1593
April missing.

By ponsford:

Alfred Price cites April 45 figures of Luftwaffe serviceability showing JG 26 and 27 could muster a little over 100 Fw 190s and Bf109s between them, which was less than either the Spitfire XIVs or Tempests facing them in NW Germany.

The problem is that a lot more was facing the 2nd TAF than just JG 26 and JG 27. There were a lot more other units on the West, not to mention that in April 1945, there was hardly a seperate 'Western' and 'Eastern' front. The Reich itself was the battleground.

I believe what you recall seeing was just the newest of Mike Williams`s brainchilds - he tries to exclude half a dozen LW unit from the unit strenght count, claiming that they weren`t in North-West Germany, but say, 100km further south or east - waving a strenght lists which shows the Luftlotte Reich only he pulled off from Holm`s site and arriving at his usual dubious conclusions.

Apart from that, I seriously doubt the RAF could muster more then 100 Tempests and Mk XIV Spitfires for operational sorties at all, there were simply not enough in Squadrons for more, and the reason for that was that they simply could not produce more, for whatever reason.

I doubt they just didn`t want to have more - that would be rather silly in view that they were still producing ca. 320 Spit IX/XVI a month early 1945, even if that Mark was obviously a bit old to meet new requirements.

[Soren]

Soren misquoted his original comments that started this long running debate to Gene - he pulled out the original context 'of designing elliptical distribution' for a high G turn and inserted mine regarding 'aeroelastic effects combined with the tip design' were the causes of the stall.

Sorry Bill but hat's just pure BS, I didn't take "your" opinion. I put it the way I've done throughout the thread.

The full elliptical lift distribution I have always maintained was achieved in turns, i.e. where aeroelasticity affects the wing and "bends" back the orginial 2 degree's of twist causing the whole wing to stall at the same AoA. That has been my argument from the start Bill.

[Marcel]

[Hop]

Total Delivered by end of month - Number delivered that month

1943 : 18 18

01-44 : 30 12
02-44 : 45 15
03-44 : 50 05
04-44 : 56 06
05-44 : 68 12
06-44 : 101 33
07-44 : 129 28
08-44 : 151 22
09-44 : 185 34
10-44 : 245 60
11-44 : 300 55
12-44 : 341 41

01-45 : 399 58
02-45 : 511 112
03-45 : 648 137
04-45 : 743 95
05-45 : 815 72
06-45 : 844 29
07-45 : 873 29
08-45 : 891 18
09-45 : 898 7
10-45 : 904 6
11-45 : 911 7

One of the documents Neil got from the NA shows deliveries of aircraft to the RAF, up to 3rd September each year.

From 4th September 1943 to 3rd September 1944, 202 Spitfire XIVs.
In the next year, again up to 3rd September, 726, which means a total of 928 by early September 1945. Your figures are about 50 short by the start of September 1944, and about 37 short by September 1945.

The problem is that a lot more was facing the 2nd TAF than just JG 26 and JG 27. There were a lot more other units on the West, not to mention that in April 1945, there was hardly a seperate 'Western' and 'Eastern' front. The Reich itself was the battleground.

I believe what you recall seeing was just the newest of Mike Williams`s brainchilds - he tries to exclude half a dozen LW unit from the unit strenght count, claiming that they weren`t in North-West Germany, but say, 100km further south or east - waving a strenght lists which shows the Luftlotte Reich only he pulled off from Holm`s site and arriving at his usual dubious conclusions.

Well, looking at the Luftwaffe claims list, scores 02/01/1945 until the end of the war against Spitfires, Typhoons and Tempests:

JG26 - 46
JG27 - 28
JG54 - 4
JG53 - 3
JG7 - 3
JG301 - 2
JG1 - 1
JG3 - 1
JG11 - 1
JG4 - 1
JG51 - 1
JG77 - 1
EJG2 - 1

(the reason for chosing the 2nd of Jan as the start date is Bodenplatte. Jan 1st wasn't typical of what units did what, either in the months before or the months after)

So 93 in total, 74 of them by JG 26 and JG 28. That's 80% by those 2 geschwader, 20% by the rest of the Luftwaffe. So the effective stregth of the Luftwaffe day fighters against the RAF was 25% larger than JG 26 and JG 27 combined.

Apart from that, I seriously doubt the RAF could muster more then 100 Tempests and Mk XIV Spitfires for operational sorties at all, there were simply not enough in Squadrons for more, and the reason for that was that they simply could not produce more, for whatever reason.

Hardly. On the 26th April 1945 the RAF had 500 Spitfire XIVs in the UK and Europe, 62 in India (or en route)

On the same date they had 426 Tempest Vs, 32 Tempest IIs.

[drgondog]

Originally Posted by Soren

Sorry Bill but hat's just pure BS, I didn't take "your" opinion. I put it the way I've done throughout the thread.

The full elliptical lift distribution I have always maintained was achieved in turns, i.e. where aeroelasticity affects the wing and "bends" back the orginial 2 degree's of twist causing the whole wing to stall at the same AoA. That has been my argument from the start Bill.

This is precisely what you said in post 64 page 5

However in the case of the 190 you will note that the wing twist was applied to such a degree as to provide elliptical lift distribution under G's (which btw is the reason for the violent departure), it was purposely done so to achieve the maximum 'e' factor and therefore L/D ratio in turns. Now ofcourse you wont see that on Lednicer's comparison as his simulation was done under 1 G, something you seem unable to grasp.


Summary of your first post which I took exception to
A. "wing twist was applied to such a degree as to provide elliptical lift distribution under G's (which btw was the reason for violent departure..


In the case of A I pointed out two things repeatedly - The departure was caused by aeroelastic effects to the wing under G loading and that the Fw 190 had an unusual twist concept - namely 2 degrees from root to zero at 81.5 percent of span - then stayed zero to the tip.

But, I pointed out, twist is applied to (ALL) trapezoidal wings to attempt to approach an elliptical wing efficiencies for lift distribution and induced drag

Here is what I said on Post 77 to support my thesis

From pages 550-551 - chapter Elements of Finite wing theory, "Principles of Ideal-Fluid Aerodynamics", Krishnamurty Karamcheti, Professor of Aeronautics and Astronautics- Stanford Univesity.. Published by John Wiley and Sons -1966

"To obtain an elliptic lift distribution on a (geometrically and aerodynamically) untwisted wing, the spanwise distribution of the chord should be elliptic"

Point 1. Elliptical Wing is the optimal planform for minimum Induced Drag
Point 2. Varying the tip ratio to approximately .4 will closely approach an Elliptical Wing as far as reducing the induced drag at the sacrifice of adding more weght (for same aspect ratio)
Point 3. The downwash corresponding to an elliptic lift distribution is a constant all along the span, further the rolling and yawing moments on such a wing are zero no matter how the chord, the angle of attack and the wing section are arranged.

Further, from 12:8-9 Spanwise Lift Distribution under Load "Supersonic and Subsonic Airplane Design" by Gerald Corning Professor Aeronautical Engineering Department - University of Maryland 1960

Point 4. The downwash corresponding to a trapezoidal wing planform varies along the span
Point 5. The spanwise lift coefficient for a trapezoidal wing planform changes with the downwash along the span.
Point 6. The G forces have bearing only on the elastic properties of the wing - and have nothing to do with lift distribution Unless and Until the wing twists or bends to change the relative angle of attack from 'no load' angle.
Point 7. The changes which tend to throw lift load Outboard are a function of bending rigidity, while the changes which tend to throw lift load Inboard are a function of torsional rigidity.

Therefore - pulling high G's seemed to affect the Fw 190 for two reasons (not known when designed) a.) aeroelastic bending of the Fw190 wing, moving the lift distribution outboard, and b.) not having twist in the outboard 20% of the span. As Lednicer quotes the LW report dated January 1944 you may presume he knows more about the German explanation than you do.

Page 89 of Lednicer's Report.

Summary-

I state unequivovally that "G forces have nothing to do with lift distribution, per se", that G forces DO affect the elastic properties of the wing which in turn DO affect the lift Distribution.

I conclude that the Fw 190 experienced the violent stall in high G turns because Aeroelastic effects combined with the lack of twist in the outer 20 percent of its span

You did not understand the reason for the violent stall until I quoted the German Report dated January, 1944 and Lednicers observations on page 89 of his report. You subsequently copied the paragraph from his report and posed it as 'your find' explaning what you had said all along on Page 6, Post 89

Oh and next time read all of what Lednicer says in his article:

Lednicer:
"A wartime Focke Wulf report (Ref. 14) indicates that at higher loading conditions (i.e. when pulling more gs) elastic deformation of the Fw 190 out wing shifts the load distribution outboard [elliptical effect = entire wing generates lift at the same angle of attack]. This would cause even more of the wing to reach its stalling lift coefficient simultaneous. Combined with the sharp stalling features of NACA 23000 airfoils, this would produce the harsh stall found in by Capt. Brown. A gentle stall would be evidenced by a more gradual progression of the 2D stall spanwise. "

Hmmm.. you turn Bill!


Summary -
Here you quote from page 89 of Lednicers Report (my reference to you in my post 77 above and present it as your idea!!

Then you quote from Gene in your Post 87
"Aeroelasticity is simply a byproduct of flying and all aircraft experience it. The NACA 23000 series of airfoils have a harsh stall with no washout due to the fact they produce elliptical lift along the entire airfoil. That means with no washout the entire wing stalls at once. This is why the FW-190's wing is twisted to prevent it.

When aeroelasticity removes this twist then the FW-190 exhibits a harsh stall."


I restate what Lednicers page 89 says

"A wartime Focke Wulf report (Ref 14) indicates that at higher wing loading conditions (i.e. when pulling more gs) elastic deformation of the Fw 190 outer wing shifts the load distribution outward. This would cause more of the wing to reach its stalling lift coefficient simultaneously. Combined with the sharp stalling features of the NACA 230xx airfoils, this would produce the sharp stall found by Capt. Brown.

Summary-
I say the issue is more related to the elastic deformation (aeroelastic effect) in the outer wing than just simply the fact that it had zero twist..

Then in your Post 89 you quote Lednicer's report paragraph word for word as I just stated it and tell me "You can't wiggle out of this one"

A wartime Focke Wulf report (Ref 14) indicates that at higher wing loading conditions (i.e. when pulling more gs) elastic deformation of the Fw 190 outer wing shifts the load distribution outward. This would cause more of the wing to reach its stalling lift coefficient simultaneously. Combined with the sharp stalling features of the NACA 230xx airfoils, this would produce the sharp stall found by Capt. Brown

Summary - so Far you appear to have moved to Lednicer from your Original Thesis below..

A. However in the case of the 190 you will note that the wing twist was applied to such a degree as to provide elliptical lift distribution under G's (which btw is the reason for the violent departure), it was purposely done so to achieve the maximum 'e' factor and therefore L/D ratio in turns. to

How did you get there?

You checked with Gene first, and quoted him directly.. but even a very good as Gene is he didn't remember the part of the Lednicer report about aeroelastic efffects - and you 'parroted' his observation about no twist was the cause for CL max being reached simultaneously (BTW I believe he is right but he forgot the part about elastic deformation in the tip region accelerating the issue)

Finally you write to Gene

Hello Crumpp,

I (Or we) need your knowledge on something, you see recently I got into an argument with a member at another forum for saying this:

The Fw-190's wing achieved elliptical lift distribution during G's because of aeroelasticity negating the original 2 degree twist applied to the 190's wing. This is what caused the violent departure in turns when pulling G's as compared to when stalling at 1 G.


This is your final 'modification' after my repeated bashings of your earlier statements and BTW is is Still Wrong in one respect.

The aeroelastic effect was Not to Negate the 2 degree twist, it was to affect the outer zero twist tip area..

I suspect that the torsional load created by the aileron, combined with the lack of twist in the outer 20% is what did it - and was TOTALLY unanticipated by any Focke Wulf structural engineers who did not have the analytical methods today to model the airframe under complex loads.

So, look at your original statements, look at my rebuttals including specifically the content from aero texts at the beginning and Lednicer's report, Look at my corrections to your statements, look at Gene's contributions and see your 'position statement above evolve -

from 'eliptical lift under high G's' to 'aeroelastic effect negating the original 2 degree twist' ... that is a long reach Soren and you still didn'tget it right.

I rest my case.

[parsifal]

I wish I knew what you just said.

[Hunter368]

Don't we all!!! LOL

Just smile and nod your head like you know WTF he said, like me. They will never know.


LOL

[parsifal]

I will never argue aviation technology again, never, never, never

[bada]

Hop:

spit14(all series) production:

MK14 :482
MK14E: 44
FR14:423 (photo recco armed but still main role is photo recco!)
FR14E:8

And the reason, at least for me, that there were so few of them is simply because the Griffon was more a complicated (also to build) engine than the Merlin, but that stays my OPINION and nothing else.(don't have any numbers or factory repports on this)

Btw: at high alt, the mk14 would have been dead meat for the k-4.
Down there, it would have been another story.

[Marcel]

Originally Posted by Hunter368

Don't we all!!! LOL

Just smile and nod your head like you know WTF he said, like me. They will never know.


LOL

Or just fall asleep Even if they said they would quit, they still can't

[drgondog]

Originally Posted by Marcel

Or just fall asleep Even if they said they would quit, they still can't

I just have unless someone a.) wishes and explanation, or b.) wants to discuss the 'art' versus 'science' of Aeroelasticity during WWII through 1960's

In which case set up another thread - this one has been trashed enough - for which I apologise

[Hunter368]

Thanks Bill.

[kool kitty89]

But Bill Gene's statement was that the NACA 23000 series airfoil featured an elliptical lift distribution when there was no washout, not that twist/washout was applied to create elliptical lift.

A Complete Waste of Space

Aeroelasticity is simply a byproduct of flying and all aircraft experience it. The NACA 23000 series of airfoils have a harsh stall with no washout due to the fact they produce elliptical lift along the entire airfoil. That means with no washout the entire wing stalls at once. This is why the FW-190's wing is twisted to prevent it.

[drgondog]

Originally Posted by kool kitty89

But Bill Gene's statement was that the NACA 23000 series airfoil featured an elliptical lift distribution when there was no washout, not that twist/washout was applied to create elliptical lift.

A Complete Waste of Space

KK - first - that wasn't Gene saying that - it was JG14_josf.. and he inserted the reference to 'elliptical' in brackets in the very same paragraph we have been using from Lednicer's report on page 89. I took Soren to task on that 'quote' as it was not accurately lifted from Lednicer.

KK - go back to I think - #77. I state (a quote from the Karamcheti text) - that only an elliptical wing will give you a wing in which there is no downwash for the entire span - without twist.

That means for a 230xx airfoil, it will exhibit elliptical lift distribution if the planform of the wing using that airfoil is a.) elliptical, and b.) untwisted. The Fw 190A (and D) both have Trapezoidal Wings and have twist (from 0 to 81.5% span).. so Zero chance of being close to 'True' elliptical... and always less than that of a Spitfire wing using the same airfoil.

A trapezoidal wing has a spanwise downwash unless it is twisted. With that twist it will 'better approximate' an ellitical wing with respect to lift distribution, but have more induced drag than the same airfoil in an elliptical planform.

The trapezoidal wing however, if given a tip chord close to .4 will result in lowered induced drag and again closely approximate an elliptical wing with No twist with respect to induced drag.. this is a simple statement overlooking the fact that it is a blanket statement with caveats.

The Spitfire wing was 'close' to being an elliptical wing and had a lift distribution 'closer' to elliptical than the Mustang and the Fw 190. But it was NOT a true Elliptical Wing and NOT a true Elliptical Lift Distribution - but definitely better than both the 51 and the 190.

The Spits also featured twist that was constant from root to tip, IIRC, but went all the way to the tip. It started at 2.0 degrees, then twisted to -.25 degrees at the tip. The twist had the effect of 'screwing up the elliptical' from optimal by shifting the Lift Distribution to higher than elliptical 'optimal inboard of the .50 spand then lower than elliptical 'optimal outboad of the .50 span. The Twist reduced the lift distribution below lowest induced drag but gave the Spit nice aileron/tip control at low speed/high angle of attack relative to the Fw 190 and the Mustang

The Fw 190 had the aforementioned 230xx airfoil which has nice lift profile, and an unusual wing with respect to the spanwise twist of its Trapezoidal wing planform. It ranging from +2 to zero at 81.5 % of span - then stops - with zero twist and zero angle to the aerodynamic chord.

That outside 20%, I believe, would give the wing a nicer lift profile in cruise and low to medium angles of attack - than it would if twisted all the way out.

But it sacrificed some margin of error in the much debated discussion, when elastic deformation under high g turning loads caused the tip area to stall below the predicted angle of attack by FW engineers (My Opinion Only).. it stalled I believe because the torsional 'deflection' twisted the mean aerodynamic chord of that area 'positive' relative to the inboard negative twist.

I could be wrong but that is my theory.

Bill