Some opinion about maneuverability of Bf109K-4

[GrapeJam]

:doh:

1. Even P-51D climb with empty weight(3,465kg-1630HP), still Bf109K-4 with maximum fuel(3,362kg-1823HP) have better P/M ratio. It means better climb rate.

 

3. Stop teasing me anymore. I don't have time to waste for a groundless dimishing. There are some good advice and opinions I have to care.

 

Oh God you still don't get it?

 

It means that because of the bad climb rate, we P51D pilots usually use more time to climb, in the meanwhile burning more fuel and lighten our aircraft further. Understand? Seriously you need me to do a ELI5 to you after the earilier post?

[gomwolf]

Oh God you still don't get it?

 

It means that because of the bad climb rate, we P51D pilots usually use more time to climb, in the meanwhile burning more fuel and lighten our aircraft further. Understand? Seriously you need me to do a ELI5 to you after the earilier post?

 

Ah... I know what you said. At first, you said about winglaoding with 100 gal fuel. Any that calculation was worng. And now you trying to say P-51 spend more fuel when It combat. Even start comfiguration was reduced 100 to 90(45gal each wing).

 

When I playing game, sometime I did combat over enemy base cuz they do not come to our side. Sometimes they come to our base. You just want to get every situation you want but it does not happen.

 

This is last answer for you.

Edited April 13, 2015 by gomwolf

[GrapeJam]

Ah... I know what you said. At first, you said about winglaoding with 100 gal fuel. Any that calculation was worng. And now you trying to say P-51 spend more fuel when It combat. Even start comfiguration was reduced 100 to 90(45gal each wing).

:doh:

We spend more fuel and time trying to get altitude, understand?

Seriously, fly the P51D for once and see if it can outturn the 109 in most scenarios, or it's just your own fault.

 

Or you know what, try to get a firm grasp of English first before getting into discussion. And when nobody has any trouble outturning the P51D except you then you should probably had started by questioning yourself 1st.

Edited April 13, 2015 by GrapeJam

[ArkRoyal]

Also the reason that Messerschmitt didn't go with full span slats is simple: It wouldn't do much good on a prop fighter. (A jet is a different matter, explanation below)

 

The span of the slats was carefully established around the knowledge that the wing root always stalls at a later AoA than the outboard section, and that the higher CLmax of the wing root is increased even further as air is accelerated over the wing by the prop when power is turned on.

 

As a result the slats were designed & placed so as to cover the areas which are out of the accelerated airstream and don't benefit from the extra lift generated in this area, the slats increasing the lift of the outboard section to match that of the root section. End result is that the overall lift of the wing with power on is increased by as much as 20%.

 

Thus that the P-51 even comes close to the turning capability of the 109 in this game is a mistake (even at 35% fuel), and one that needs correcting.

 

The 109s slats weren't full span because manufacturing processes at the time made it impractical for production, the things you mention only explain why they were outboard instead of inboard.

[Yo-Yo]

Anyway, the P51D at standard load doesn't outturn the K4 in either direction, those that do have 35% fuel loaded(around 100 US Gallons, the same fuel load as the K4), and only to the right, with flaps, but if the K4 also pop flaps then no way the P51D can outturn the K4.

 

In case you didn't know, at 35% fuel the P51D had 24km/m2 lower wings loading than the K4.

 

Also, btw, you're comparing airfoil drag but forgot airframe drag.

 

And all of you have forgotten induced drag that is much more than non-induced drag in loaded turns. :)

[Yo-Yo]

Yo-Yo, I think, that you're overlooked many important things about the automatic Slats.

 

1/ The automatic slats was added to the wing design of Bf-109 for ensure the maneuverability in combat, at low or medium speed, and high AoA. Not only for landing such as; Storch, An-2 o that you say.

I think, you must studying, why the Lavochkin La-5 and LAGG-3 (35 series) was equipped with automatics slats, copied from Bf-109 for fighting against Bf-109.

 

In the book " DESIGN FOR AIR COMBAT" by Ray Whitford -1987- The benefits of automatic slats in combat, are well explained:.

""" Slat with a slot (slotted stat)

Though complex, requiring rails and rollers in addition to actuators, this is probably the most widely used leading-edge device for combat aircraft. However, when account is taken of the resulting increase in maximum lift and its favourable effect on lateral/directional flying qualities, the extra complication is amply justified.

....

The slotted leading edge was originally proposed by Handley Page and Lachmann around 1920 and proved extremely beneficial in extending the lift curve, as shown in Fig 64. Designed to operate automatically, it consists of a slat quite free to move on tracks. At low AOA the slat is held flush against the leading edge. At high AOA the high local suctions on the slat create a forward chord-wise force, pulling out the slat. The slot so formed allows the wing to continue lifting to a higher AOA. significantly increasing the maximum lift coefficient. A slight chord extension also occurs. """""

Fig. 64

 

 

2/ the abrupt wing drop and ailerons low effectiveness that you say, was not a worrying case or usual case flying a Bf-109, due to it may occur only at landing at very low speed.

On contrary, wing drop and ailerons low effectiveness was a very important problem in the P-51 in tightened turns, and this was well know by the pilots, but this stall behavior of P-51 is poorly modelled in DCS too.

 

Moreover. you can turn with ailerons to 45 degrees of bank or more, then and pull for a tight turn with elevator and high AoA, and aileron flushed in the wing, and applying the rudder as necessary, whitout wing drop or any ailerons negative effecs.

 

Stall can be encountered AT ANY SPEED and aileron become less effective regardless of speed but depending on AoA.

[Yo-Yo]

as it is now, the flaps give you no advantage in turning with the 109 at all it seems.

we did a couple of test turns against each other, and we were all quite surprised that the flaps didnt help at all...usually even the 109 with flaps down stalled first.(we tried several different position of flaps)

 

Flaps rarely helps in sustained turn but could be useful to reduce turn radius pulling maximal tight turn. And not more than 10-20 degrees.

[gomwolf]

And all of you have forgotten induced drag that is much more than non-induced drag in loaded turns. :)

 

That is good point. I think induce drag of both aircraft almost equal. Both aircraft use taper-wing and P-51 have longer wingspan but Bf109 have round wingtip. I don't have documents about it but I think I can find something.

[gomwolf]

Flaps rarely helps in sustained turn but could be useful to reduce turn radius pulling maximal tight turn. And not more than 10-20 degrees.

 

Hmmm... Afaik there is enough thrust in there, flap is good for sustain turn. stalling earlier when lowered flap is natural. There is no problem because flap make CLmax high but it make stall angle smaller. This link shows effect of flap.

 

http://www.simhq.com/_air/images/air_002b_10.gif

 

There are lots of situation in sustain turn fight, but AoA in sustain turn is not quite big. It cannot over stall angle I think. Because its low speed(around 200mph 3~4G).

[ArkRoyal]

Hmmm... Afaik there is enough thrust in there, flap is good for sustain turn. stalling earlier when lowered flap is natural. There is no problem because flap make CLmax high but it make stall angle smaller. This link shows effect of flap.

 

http://www.simhq.com/_air/images/air_002b_10.gif

 

There are lots of situation in sustain turn fight, but AoA in sustain turn is not quite big. It cannot over stall angle I think. Because its low speed(around 200mph 3~4G).

 

Since he specifically mentioned that it reduces radius, he most probably meant that it does not improve turn rate........so he isnt contradicting anything.

[OutOnTheOP]

Thus that the P-51 even comes close to the turning capability of the 109 in this game is a mistake (even at 35% fuel), and one that needs correcting.

 

The P-51 DOESN'T come close to the turn rate of the Bf109 in DCS at low speed. Unless you are a particularly incompetent pilot, or have not actually *flown* the P-51 in DCS, you would have noticed this.

 

At *high* speed, the Mustang can turn with (or inside) the Bf109. This is completely accurate.

 

Conversely, if the Bf109 chooses to turn tighter than the Mustang can turn, it may do so, but does it at the cost of extremely high airfoil drag due to the high alpha. Mustang can't follow this turn, but would be stupid to try. Blow through, go high yo-yo, and get the Bf109 while it wallows in low energy state.

[OutOnTheOP]

:huh:

 

Actually, this thread for the performance(one more actually, not even in game performance) not my skill.

 

Here is my answer.

 

First, yes I love scissors, rolling scissors, high and low yo-yo, continuous loof, and that kinds of interwinding manevers. If I can get good point for BnZ, I did it. However, in most case I play this game with more than 350 ping and in DCS as you know wing structure of Bf109 is too weak for it. I lost my wing several times for it.

 

Second, I agree that difficulty of maintaining turn with Bf109 in high speed is quite good. I really satisfied about stick movement in high stick force situation. However I think Bf109K-4 in history does not have serious fluttering at low speed turning like game and have better stall performance.

 

Holy crap, way to still miss the point.

 

Let me break this down real simple:

 

Bf109 turn fast.

Fast turn cost speed.

Fast turn cost speed regardless of wing type.

[OutOnTheOP]

And all of you have forgotten induced drag that is much more than non-induced drag in loaded turns. :)

 

Hardly; reference my point about the rapid turn ability of the Bf109 being self-defeating because of the high drag that accompanies it. I may not have explicitly delineated that high alpha= high induced drag= huge speed loss, but I thought that could be assumed to be implied in a forum specializing on combat aircraft.

 

Perhaps I should not assume this, considering the last person that tried to argue why the Bf109 should be better at turning didn't understand that AoA in a flat spin is NOT, in fact, zero :music_whistling:

[9.JG27 DavidRed]

Flaps rarely helps in sustained turn but could be useful to reduce turn radius pulling maximal tight turn. And not more than 10-20 degrees.

 

in the p51 they help quite a bit.

[ArkRoyal]

in the p51 they help quite a bit.

 

They have almost no effect on the sustained rate, mostly the radius. Also the P-51s flaps are nearly twice as big.

[gomwolf]

Holy crap, way to still miss the point.

 

Let me break this down real simple:

 

Bf109 turn fast.

Fast turn cost speed.

Fast turn cost speed regardless of wing type.

 

Are your point of former thread is the reason of high AoA turn is not good choice in air combat manerver?

 

So I explain the maneuvers I prefer and why I didn't use energy fighting in this game. I think it is right answer about your opinion, but you don't.

Edited April 14, 2015 by gomwolf

[Kurfürst]

Out of curiousity, did anyone tested the best sustained turn time of the 109K in DCS?

[messermeister]

If I am not misinformed, the BF-109 V-24 (VK+AB) was a pre-production prototype of Bf-109F with clipped wings as Bf-109E.

As a result of the tests in the wind tunnel, the effect "aileron drops" of "Emil" series was removed, but the automatic slats were not eliminated.

When the slats are deployed drag is increased, .. if the Slats would not increased the CL properly, surely the Dr.Eng. Willy Messerschmitt would have eliminated the slats without hesitation from the biginning.

 

 

I'm not sure to follow you, but wind tunnel tests on V24 showed small or no influence at all for Cl max, and also no appreciable difference on Cd.

 

Oh, and while OT, the aircraft in your photo is W.Nr. 5604, not V24 (W.Nr. 1929).

 

I think my illustration is not exaggerated, because it is very similar to the areas of influence of the slats marked on the sketch you've shared from the report of Bf-109G6 of 1944.

Please, If you want, share the full report of that Bf-109G6 from 1944, so we can see what final results are reporting.

 

What is exaggerated is the effect of slats on Cl max, at least in relation to Bf 109, as this is not backed by known primary sources.

 

The report 109 09 E 44 is about change of bearings in slats (kugellager/gleitlager). It contains no Cl measurements, but has this sketch illustrating the effect of slats over the airflow in different stall phases.

[gomwolf]

Hummm.. It is my fault. I didn't explain it first.

 

I started this thread with turning performance of Bf109K-4 and P-51D in this game, because here is DCS forum. However my intent of this thread is turning performance of Bf109K-4 and P-51D "in history".

 

Of course, here is DCS forum and if you want to talking about in game performance, that is no problem, but I just want you guys know my intent when you writing something.

Edited April 14, 2015 by gomwolf

[NineLine]

I started this thread with turning performance of Bf109K-4 and P-51D in this game, because here is DCS forum. However my intent of this thread is turning performance of Bf109K-4 and P-51D "in history".

 

Well ED's goals are that they are one in the same ;)

[Teapot]

Well ED's goals are that they are one in the same ;)

 

Indeed; and it's why ED are (and always have been) the finest flight simulation creators/designers on the planet ... bar none!

 

(Fond memories of Flanker 1.1 / 1.2 ... The perfectly poised statuesque & beautiful Sue with those pendulum like air intakes ... my first love ... and I remember the raging debates in those days too!)

[OutOnTheOP]

Are your point of former thread is the reason of high AoA turn is not good choice in air combat manerver?

 

So I explain the maneuvers I prefer and why I didn't use energy fighting in this game. I think it is right answer about your opinion, but you don't.

 

If you understand the relationship between AoA and drag, and the resultant impact on airspeed, then stop complaining that the Bf109 isn't maneuverable enough. If you use it inefficiently and stick to a band of the performance envelope in which you are unlikely to gain an advantage, that is no fault of the aerodynamic performance of the aircraft

[Hummingbird]

The 109s slats weren't full span because manufacturing processes at the time made it impractical for production, the things you mention only explain why they were outboard instead of inboard.

 

That is just ridiculous, full span slats would've been just as easy to produce and were infact manufactured and used on several other aircraft designs where the wing was raised above the prop wash. Putting full span flaps on a prop job with the wings situated directly in the middle of the prop wash would've been an extremely bad move as the slats deployment would then be counteracted during a large part of the AoA range, which in the end would only result in an actual loss of lift when it was most needed.

 

In short your theory is false and completely illogical.

Edited April 14, 2015 by Hummingbird

[Hummingbird]

The P-51 DOESN'T come close to the turn rate of the Bf109 in DCS at low speed. Unless you are a particularly incompetent pilot, or have not actually *flown* the P-51 in DCS, you would have noticed this.

 

Well that's not what a bunch of people are saying atm, they are saying that the P-51 can keep flying at speeds where the Bf-109 stalls out, which is ridiculously unrealistic. People are saying that the 109 outturns the P-51 only at medium speeds ingame, and that this is due solely to the 109s extra engine power, implying that the 109's ITR is lower than the P-51s, which again is whoefully unrealistic.

 

At *high* speed, the Mustang can turn with (or inside) the Bf109. This is completely accurate.

 

Define high speed. Also the reason for this has nothing to do with lift or drag (unless you wanna use the same source as Yo-Yo ofcourse and pit a P-51 with filled, waxed & polished wings against a 109 in operational condition :lol: ) , but with control forces. In short you'd have to go VERY fast to be able to turn inside a 109 in the P-51 in reality, as the speed at which the 109 pilot cannot pull full deflection with two hands on the stick is somewhere around 400 mph.

 

Conversely, if the Bf109 chooses to turn tighter than the Mustang can turn, it may do so, but does it at the cost of extremely high airfoil drag due to the high alpha. Mustang can't follow this turn, but would be stupid to try. Blow through, go high yo-yo, and get the Bf109 while it wallows in low energy state.

 

This is true for any aircraft that turns tighter, like a Spitfire, and like a Spitfire the Bf-109 doesn't have to choose to turn tighter, he can simply choose to pull the same AoA and speed around the same size circle a lot faster than the P-51 due to a much lower power loading AND drag penalty (the latter because being lighter he needs less lift and thus drag to achieve the same turning circle). But do we see this ingame? I don't think so.

 

The main reason is that atm the game is using assumed lift & drag figures that combine to an incorrect L/D ratio for all three ww2 prop jobs, which in addition are giving us some of those funny performance anomalies we see so many complaining about. That combined with incorrect flight behavior, such as the 109's extremely twitchy behavior near stall completely unlike anything it has ever been described as featuring and more akin to how a 190 would behave, results in a very inauthentic experience.

Edited April 14, 2015 by Hummingbird

[gomwolf]

If you understand the relationship between AoA and drag, and the resultant impact on airspeed, then stop complaining that the Bf109 isn't maneuverable enough. If you use it inefficiently and stick to a band of the performance envelope in which you are unlikely to gain an advantage, that is no fault of the aerodynamic performance of the aircraft

 

 

 

1. Of course I already know relationship between AoA and drag.

2. I am not complaining about Bf109 is not maneuverable enough.

3. My kill ratio is not bad like you think. Even I play with 350 ping.

 

You completely does not understand my point. The reason I written this thread is not talking about pilot skill or complain about FM of DCS. If I want complain about DCS, I told it more clearly and does not care anymore like the other thread about MK108 because my english is not good. I just want discuss about historical aircraft performance in flight sim forum.

Edited April 14, 2015 by gomwolf