109 sustained turn performance

[JG7_X-Man]

On 8/18/2020 at 5:17 AM, Aurora_Stealth said:

And 0:44 for the following video.

 

 

 

I love that! This has slats!

 

Actually, Chuck Yeager and Bud Anderson both said the P-51 was faster and had more range than the Fw 190 and Me 109, but they were all equally maneuverable.

 

Proof that history belongs to the victor.

Edited August 24, 2020 by JG7_X-Man

[JG7_X-Man]

4 hours ago, Holtzauge said:

First part essay 500 words. Second part multiple choices of the type "What is the maximum lift coefficient of the Me-109 K4?" (1=below 1.1, 2=About 1.4, 3=Well in excess of 5) which is why I suspect some will fail miserably.

 

Actually this bring up a very good point. I have always wondered if the game's FM was too heavily dependent on Wing Load and not enough on Power/Mass ratio.

[RedKestrel]

4 hours ago, Holtzauge said:

First part essay 500 words. Second part multiple choices of the type "What is the maximum lift coefficient of the Me-109 K4?" (1=below 1.1, 2=About 1.4, 3=Well in excess of 5) which is why I suspect some will fail miserably.

Just always choose C, its a winning strategy if I ever heard one.

[Floppy_Sock]

I think the discussion was somewhat derailed from the original intent by me when asking about Cl values. 

 

We were originally interested, specifically, in induced drag's effect on the 109's turn sustained performance. 

 

Using these sustained turn tests is only part of the answer though since we need to understand how the devs in IL2 model thrust. 

 

I'm sure @Holtzauge can provide some input here but with my limited understanding I feel we need to come up with some more fundamental tests to approximate thrust and Cd0 such that induced drag can be singled out as a culprit. 

 

For Cd0 - one could attempt a deceleration test. If performed at high speeds, induced drag can be assume to be small w.r.t. parasitic drag. Though this will introduce Mach related considerations (maybe you can chime in here holtz, I'm not familiar with aero theory to comment off the cuff.)

 

To measure thrust, one can *attempt* to calculate the dynamic thrust by measuring acceleration. Of course this is a poor idea from the outset since thrust varies with forward airspeed, as do drag values, especially at slow air speeds during the transition from predominantly lift induced drag to parasitic drag. Maybe someone can come up with a better way. 

 

Once those 2 values have been pinned down, then sustained turn times can give an indicator of whether or not the 109's FM has a CDi problem. 

 

Edited August 20, 2020 by Floppy_Sock

[Panthera]

@Floppy_Sock It can't actually be a Cdi issue as the Cdi is directly tied to Cl, so it has to be either a Cd0 or thrust issue, and I doubt it is thrust as then accurate level speeds wouldn't be possible.

 

My suspicion is that for some reason extra parasitic drag has been added by the devs for when the slats pop out, eventhough in reality there is no measurable increase in Cd when this happens.

 

This would also explain why the DCS K-4 is able to sustain a such higher G load (+0.4 G's) than the IL2 K-4.

[Floppy_Sock]

18 minutes ago, Panthera said:

@Floppy_Sock It can't actually be a Cdi issue as the Cdi is directly tied to Cl, so it has to be either a Cd0 or thrust issue, and I doubt it is thrust as then accurate level speeds wouldn't be possible.

 

My suspicion is that for some reason extra parasitic drag has been added by the devs for when the slats pop out, eventhough in reality there is no measurable increase in Cd when this happens.

 

This would also explain why the DCS K-4 is able to sustain a such higher G load (+0.4 G's) than the IL2 K-4.

 

Why can it not be an induced drag issue? Do we have another data point somewhere that rules out Cdi?

Edited August 20, 2020 by Floppy_Sock

[III/JG52_Otto_-I-]

On 8/16/2020 at 6:19 PM, Talon_ said:

Slats are designed as nothing more than a landing aid, confirmed by historical pilot accounts. One popping out before another in a high-AoA turn is a recipe for disaster, and one wing is always flying faster than another in a turn unless perfectly coordinated.

You're late to tell it to the Americans, because they copied the automatic LE slats of Messerschmitt for the NAA F-86 Sabre, and Douglas A-4 Skyhawk. 
You are completely wrong, because the asymmetric opening of the LE slats is only dangerous problem during landing and take off at low speed, but in rest of air combat manoeuvring is and advantage.
Automatic LE Slats allow to recover a stalled semi-wing lift in tight turns and spins almost instantly.
A lot of WWII aircrafts, and onward inproved his tight turns behavior adding LE slats in theirs wings, such as, LAGG-3, MIG-·3, La-5, Curtiss SB2, F-86 Sabre, etc.  
 

Spoiler

 

 

On 8/15/2020 at 8:04 PM, Cpt_Siddy said:

What model, are slat drag involved?  (people think that slats are "free lift" at low speed, well kids, lift = drag, more lift = more drag)

This physic law is the same for ALL aircrafts in game, not only for the BF-109. ..Casually allies fanboys forget it. 
By the way, this law is applicable too for guys who fly aerobatic combat maneuvers with FULL FLAPS down.
 

Edited August 20, 2020 by III/JG52_Otto_-I-

[III/JG52_Otto_-I-]

5 hours ago, 71st_AH_Barnacles said:

Is this of any use?

 

Yes, you can see in this charts that F-51 with 8,000 lb TOW (3,630kg) is not able to turn same as P-51 D-15 in game with 10,000 lb (4,535 kg) of typical TOW.
This F-51 stalls at 200 Mph (320 kph) IAS with 4.5 G´s pull out manoeuvre.... At that speed you can pull about 6 to 8G´s without pilot blackout in game with the P-51D-15, what is 2,000lb  (907 kg) heaviest.
That mean the Pony stall behaviour is clearly overmodelled  

Edited August 20, 2020 by III/JG52_Otto_-I-

[Barnacles]

4 minutes ago, III/JG52_Otto_-I- said:

Yes, you can see in this charts that F-51 with 8,000 lb TOW (3,630kg) is not able to turn same as P-51 D-15 in game with 10,000 lb (4,535 kg) of typical TOW.
This F-51 stalls at 200 Mph (320 kph) IAS with 4.5 G´s pull out manoeuvre.... At that speed you can pull about 6 to 8G´s without pilot blackout in game with the P-51D-15, what is 2,000lb  (907 kg) heaviest.
That mean the Pony stall behaviour is clearly overmodelled  

It'd be good to see why. Like you pointed out the F51 is actually lighter, so the argument that it is a slightly different model doesn't support the 51 in game being able to pull so many G, as this graph is radically different.

[III/JG52_Otto_-I-]

29 minutes ago, 71st_AH_Barnacles said:

It'd be good to see why. Like you pointed out the F51 is actually lighter, so the argument that it is a slightly different model doesn't support the 51 in game being able to pull so many G, as this graph is radically different.

My point is that the Pony in game is more heavy, and the P-51 D-15 in game would be worst in stall behavior  than this chart explain. 

 

[Talon_]

16 hours ago, Holtzauge said:

I just realized that this whole discussion about Clmax and turn rates is actually a bit of a groundhog day since it was all covered exhaustively already back in 2016 here.

 

This certainly makes me feel more confident in considering this thread to be normal 1-0-whine.

[Barnacles]

7 hours ago, III/JG52_Otto_-I- said:

My point is that the Pony in game is more heavy, and the P-51 D-15 in game would be worst in stall behavior  than this chart explain. 

 

Yes, that's what I said.

 

Now we have a g meter in game it's possible to draw up a similar chart for the in game plane.

Edited August 21, 2020 by 71st_AH_Barnacles

[Panthera]

LE slats were actually invented around  the same time by both the Germans & British, the first patent being filed in 1918 by Gustav Lachmann. Handley Page came up with the same idea independently. But the mechanism allowing them to operate reliably under G's didn't arrive until later. 

 

13 hours ago, Floppy_Sock said:

 

Why can it not be an induced drag issue? Do we have another data point somewhere that rules out Cdi?

 

Because if the lift induced drag (Cdi) is increased then so is the lift (Cl), and the aircraft only needs a specific amount of Cl to maintain a certain rate of turn. 

Edited August 21, 2020 by Panthera

[Holtzauge]

14 hours ago, Floppy_Sock said:

I think the discussion was somewhat derailed from the original intent by me when asking about Cl values. 

 

We were originally interested, specifically, in induced drag's effect on the 109's turn sustained performance. 

 

Using these sustained turn tests is only part of the answer though since we need to understand how the devs in IL2 model thrust. 

 

I'm sure @Holtzauge can provide some input here but with my limited understanding I feel we need to come up with some more fundamental tests to approximate thrust and Cd0 such that induced drag can be singled out as a culprit. 

 

For Cd0 - one could attempt a deceleration test. If performed at high speeds, induced drag can be assume to be small w.r.t. parasitic drag. Though this will introduce Mach related considerations (maybe you can chime in here holtz, I'm not familiar with aero theory to comment off the cuff.)

 

To measure thrust, one can *attempt* to calculate the dynamic thrust by measuring acceleration. Of course this is a poor idea from the outset since thrust varies with forward airspeed, as do drag values, especially at slow air speeds during the transition from predominantly lift induced drag to parasitic drag. Maybe someone can come up with a better way. 

 

Once those 2 values have been pinned down, then sustained turn times can give an indicator of whether or not the 109's FM has a CDi problem. 

 

 

13 hours ago, Floppy_Sock said:

 

Why can it not be an induced drag issue? Do we have another data point somewhere that rules out Cdi?

 

You are quite right: It may very be well be a Cdi related problem and it really creates a lot of friction when people state things as facts when in reality it is simply their opinion and conviction and not a fact at all. In addition, it does not help when they are plain wrong:

 

While it is true that Cdi is coupled to Cl, there is also in the denominator a term ”e” sometimes referred to as the Oswald factor. This factor denotes how well aligned the lift distribution over the wing is to an elliptical pattern which is defined as e=1. However, wings are usually not elliptical in shape and even those that are usually has washout built in (e.g. like the Spitfire). So ”e” is usually also in IRL less than 1 and is commonly set to a fixed value, say 0.8 which gives good approximations in most cases. However, what happens at high angles of attack is that the flow partly breaks down which then means that the lift distribution over the wing departs even further from elliptical meaning that the factor ”e” goes down even further.

 

This is why in my simulation e is a function of Cl meaning you have to have an idea of how e is connected to Cl. So in many cases my low Cl e is around 0.8 but then at higher Cl e goes down substantially. This means that if I model this optimistically or pessimistically I can totally different results meaning there is every possibility that a model of the induced drag can be right or wrong.

 

So if someone says it can’t be a Cdi issue as the Cdi is directly coupled to Cl they are plain wrong even though the statement is presented as a fact.

 

Now about the thrust being off I think when it comes to the best turn rate issue evidence as I see it points to thrust being correctly modeled at those speeds after all since if it was related to the thrust modeling, then the climb rates would be off as well which as far as I know they are not. Rationale: If the thrust model for turning at 300 Km/h IAS was off then so would the climb rates at 300 Km/h IAS.

 

In addition, as I see it all in-game measurements posted so far for both the P-51D and Me-109K4 align well with my simulations meaning I don’t see a problem but that of course does not rule out that both my simulations and the modeling in IL2 is off but so far I have seen nothing that convinces me of this.

 

However, as I said before, there may be an issue with the thrust or drag modeling below speeds for best turn and climb rate but in that case I think all bets are off if it’s a thrust or drag issue because you can’t use the climb rates anymore to check the thrust modeling. One way to test this though would be to test acceleration from speeds below best climb rate (basically prop hanging) and then see how long time it takes to reach say 400 km/h IAS. I can do acceleration estimates in my simulator but I’m not going to post too much here since I nurture a vain hope to publish a book on aircraft performance some day and if I reveal everything now no one will bother to get it.

 

[Panthera]

@Holtzauge I don't see a reason to suspect a difference in "e" , usually it is assumed to be around the same for these aircraft, just like you did yourself.

 

I think you're a little too obsessed with trying to prove me wrong atm instead of actually trying to be constructive and helping to figure out the issue. I don't know if it's because I proved you wrong about the slats and Cd and that this somehow hurt your pride, but you certainly took a 180 deg change in mood after that. 

 

 

 

1 hour ago, HomicideHank said:

Actually, Handley Page came up with the idea first and built the worlds first operating slat in 1917. He also filed the first successful patent for a controllable device in which the slot could be opened and closed by the pilot.

 

Lachmann on the other hand failed to patent his version of the slat in 1918 after which he gave up on the idea. Only in 1921 when he read about Handley Page's slats he got interested in them again.

 

Close but no cigar. Still an impressive feat to be the second guy in the world to come up with the idea.

 

Seems pretty odd for Handley to seek an ownership agreement with Lachmann then  

 

 

Edited August 21, 2020 by Panthera

[Holtzauge]

1 hour ago, Panthera said:

@Holtzauge I don't see a reason to suspect a difference in "e" , usually it is assumed to be around the same for these aircraft, just like you did yourself.

 

I think you're a little too obsessed with trying to prove me wrong atm instead of actually trying to be constructive and helping to figure out the issue. I don't know if it's because I proved you wrong about the slats and Cd and that this somehow hurt your pride, but you certainly took a 180 deg change in mood after that.

 

Well you see this is exactly what gets you into problems: Either you simply did not understands what I wrote when I said e was a function of Cl or you are willfully misrepresenting the situation when you say we agree about e. About proving you wrong I don't need to do that since you are doing an admirable job of that yourself. I just point out the inconsistencies that's all. Being wrong is bad enough but assuming a superior attitude and asking people like you did earlier if they have formal education in aerodynamics when they air different opinions than yourself just digs you deeper down that credibility hole. Putting you on ignore would probably be the best course of action but since you insist on framing your hypothesis and conjectures as facts this could do untold damage. That being said don't expect any more replies to me. I will just intervene if it's absolutely necessary.

[Panthera]

That's certainly an attitude. 

 

I had a hunch it wasn't all ZachariasX's own words back there, seems I was right, so I see where it is I angered you now. 

 

Shame to see you stoop like this Holtzauge, as I really do like your C++ simulations and general input. 

Edited August 21, 2020 by Panthera

[AndyJWest]

This 'how good is the BF-109 at turning' forum dogfight is boring. It just goes around in circles endlessly. I blame the AI... ?

[unreasonable]

 I admit when I saw this video - actually an extract from one - I was reminded of the Il-2 forum.

 

 

[AndyJWest]

The turn performance would be better if the outside middle wheel stayed on the rails. Though derailments can be entertaining...

[Holtzauge]

That car would complete that circle much faster if BRIO put slats on it.

[Panthera]

Nah, the oswald efficiency factor isn't high enough. 

[LukeFF]

6 hours ago, AndyJWest said:

This 'how good is the BF-109 at turning' forum dogfight is boring. It just goes around in circles endlessly. I blame the AI... ?

 

I've been following this topic as well and have been wondering what exactly the whole point has been all along. If I had enough time to type all of these verbose replies, I'd much rather be spending my time actually flying the game than debating things like (checks notes) when slats were first invented. ? 

[Mitthrawnuruodo]

46 minutes ago, LukeFF said:

 

I've been following this topic as well and have been wondering what exactly the whole point has been all along. If I had enough time to type all of these verbose replies, I'd much rather be spending my time actually flying the game than debating things like (checks notes) when slats were first invented. ? 

 

I'm convinced that many people find the discussion or debate (if you can call it that) more interesting than the game itself. In fact, I wouldn't be surprised if there were a few frequent posters on the forum that almost never actually play the game.

 

Most are here just for the flying, but some enjoy things such as research, testing, skinning, mission design, or server admin. All these activities can require a lot of time. Ultimately I think it's good that people with a wide variety of interests participate.

 

Of course certain topics just go around in circles forever, but that's not always the case.

Edited August 21, 2020 by Mitthrawnuruodo

[Panthera]

At this point I'm just really interested in how there can be such a big difference in the sustainable G between DCS & IL2 for these two aircraft, it's like two different realities.

 

Only thing I can say in addition to that is that DCS's FMs tie more closely with pilot opinion as well as my own understanding of how these two aircraft should fly.

 

 

 

 

 

 

[Floppy_Sock]

49 minutes ago, Panthera said:

At this point I'm just really interested in how there can be such a big difference in the sustainable G between DCS & IL2 for these two aircraft, it's like two different realities.

 

Only thing I can say in addition to that is that DCS's FMs tie more closely with pilot opinion as well as my own understanding of how these two aircraft should fly.

 

 

 

 

 

 

 

Panthera, I have some scripts written to make EM diagrams in DCS as well. 

 

I will run a test with the DCS 109 in a similar configuration to P_s = 0 curve I posted earlier in the thread. 

 

The only test I've done between il2 and DCS is the spitfire and sustained performances were very close. Of course, that's a completely different module so things might be very different in the 109. I should have some time this weekend to do it.

[Panthera]

6 hours ago, Floppy_Sock said:

 

Panthera, I have some scripts written to make EM diagrams in DCS as well. 

 

I will run a test with the DCS 109 in a similar configuration to P_s = 0 curve I posted earlier in the thread. 

 

The only test I've done between il2 and DCS is the spitfire and sustained performances were very close. Of course, that's a completely different module so things might be very different in the 109. I should have some time this weekend to do it.

 

Sounds good floppy, looking forward to seeing your results

 

Edit: Should note that the K4, amongst others, appear to be struggling with an MW50/engine bug since last patch to DCS's open beta, the cockpit shaking when you go past 1.42ata, and the aircraft refusing to go past 550 kmh or so. So you'll have to run the tests on the stable version for now.  

 

 

Edited August 22, 2020 by Panthera

[III/JG52_Otto_-I-]

14 hours ago, unreasonable said:

 I admit when I saw this video - actually an extract from one - I was reminded of the Il-2 forum.

 

Spoiler

 

 

 I think that we can consider this post as a perfect TROLLING by book

Edited August 22, 2020 by LukeFF

[Aurora_Stealth]

Here's a brief follow-up from the tests I did earlier in the thread, to complete this dataset at the lower speed range - now including from 300 km/h down to 240 km/h in increments.

 

I've also added another comparative one at 290 litres for Holtzauge.

 

 

The lowest I was able to record was 240km/h, which was teetering on the stall and below that it was looking sketchy... at 230km/h there was typically a wing drop at these bank angles.

 

Hope some of the data is useful anyway.

[Floppy_Sock]

On 8/21/2020 at 7:37 PM, Panthera said:

 

Sounds good floppy, looking forward to seeing your results

 

Edit: Should note that the K4, amongst others, appear to be struggling with an MW50/engine bug since last patch to DCS's open beta, the cockpit shaking when you go past 1.42ata, and the aircraft refusing to go past 550 kmh or so. So you'll have to run the tests on the stable version for now.  

 

 

Unfortunately there's a bug with the 109 in DCS atm where everything's shaking in the cockpit. Not sure if it's purely superficial but it makes testing a pain so I'm going to wait until that's fixed. 

 

Edit: I did it anyway @Panthera

 

 

 

DCS doesn't really allow for sustained turn rates below about 200 mph TAS because at full power the plane wants to roll so badly it's not possible to keep the plane level enough to get good data.

 

Test conditions for both aircraft:

 

altitude: < 300m

fuel: 50%

Ammo: full

Power settings: 1.8 ata

 

Standard atmosphere in both sims. 

 

Conclusion - there's almost no discernible difference. Certainly not the 0.5g that was proposed above. At least my tests do not see anyT

Edited August 24, 2020 by Floppy_Sock

[Panthera]

3 hours ago, Floppy_Sock said:

Unfortunately there's a bug with the 109 in DCS atm where everything's shaking in the cockpit. Not sure if it's purely superficial but it makes testing a pain so I'm going to wait until that's fixed. 

 

Edit: I did it anyway @Panthera

 

 

 

DCS doesn't really allow for sustained turn rates below about 200 mph TAS because at full power the plane wants to roll so badly it's not possible to keep the plane level enough to get good data.

 

Test conditions for both aircraft:

 

altitude: < 300m

fuel: 50%

Ammo: full

Power settings: 1.8 ata

 

Standard atmosphere in both sims. 

 

Conclusion - there's almost no discernible difference. Certainly not the 0.5g that was proposed above. At least my tests do not see anyT

 

Might have to wait until the K-4's engine power is back Floppy, or you can try the stable version.

 

My results are 3.6-3.7 G's sustained at 200 kts TAS (370 km/h) for the K-4 in DCS (before the cockpit shake/power loss bug), full fuel (400 L), sea level. In IL-2 it was 3.3 G's, same conditions. Also don't forget to test the P-51 in both sims as well.

 

I'll redo my tests once the aircraft bugs have been fixed, which will probably be soon.

 

PS: To keep things simple please stick with 400 L fuel, so we're testing the same weights.

 

 

Edited August 24, 2020 by Panthera

[Holtzauge]

12 hours ago, Aurora_Stealth said:

Here's a brief follow-up from the tests I did earlier in the thread, to complete this dataset at the lower speed range - now including from 300 km/h down to 240 km/h in increments.

 

I've also added another comparative one at 290 litres for Holtzauge.

 

 

The lowest I was able to record was 240km/h, which was teetering on the stall and below that it was looking sketchy... at 230km/h there was typically a wing drop at these bank angles.

 

Hope some of the data is useful anyway.

 

Thanks for doing the additional low speed turn rate testing @Aurora_Stealth. That the Me-109K4 was under performing at very low speeds was just a subjective feeling on my part based on how I perceive it to behave in-game but comparing your measured numbers to what I was expecting based on my simulations it does not look like there actually is anything off in-game at speeds ”behind the curve” because I don’t get any shorter turn times at speeds below the speed for best turn rate for the K4.

 

TBH, I’m really impressed how well the planes in BOX are modeled given that everything has to be done in real time while in my simulations I have no such constraints and while turn rate estimates just take a few seconds for me to run, time to climb estimates take minutes. So we can be very happy with what we have and that the developers are doing such a great job continuously developing this fine simulator.

[Aurora_Stealth]

Seems like I've already used up my up-votes for the day. So I'll just put it into this message - thanks for checking using your simulations/calculations @Holtzauge and I'm glad to hear you're satisfied with the data.

 

I agree the Dev's do an excellent job, and applaud their continuous improvement efforts. This game and its spin-off's cover quite a bit of ground.

 

That is reassuring... and I'm glad to hear it - but still it unfortunately doesn't answer the fundamental concern behind this thread. The data provided by Panthera shows a significant contradiction with the G's pulled (will be interesting to hear what Floppy Sock gets on his charts once reliable engine performance is restored in DCS). I also think there is weight behind this concern as we know that the flight modelling is more...  sophisticated in some regards with DCS but this should not be viewed as a significant criticism to IL-2 - the development priorities and focus are different.

 

There may be an underlying issue with energy bleed and we're not seeing this play out from individual turn times in the dataset due to maintaining of a set speed and adjusting the bank angle accordingly - this is not the same as performing a minimum turn radius. Ultimately the Bf 109 K turning performance in IL-2 is known to be disadvantageous to the P-51 which is false, so we shouldn't be celebrating early. We know the extreme CLmax number with the Tempest is responsible regarding that particular comparison, so the next question is to tie down where the disparity is coming comparatively with the P-51.

Edited August 24, 2020 by Aurora_Stealth

[Aurora_Stealth]

Okay, cheers Hank.

 

We're going to see some differences - as we're using different maps and season setting which will affect temperature and pressure I imagine.

[Holtzauge]

My apologies @Aurora_Stealth: Parallel to this Me-109K4 issue I’m modeling the Pfalz D.VIII and unfortunately I did the latest run of the Me-109K4 in the wrong C++ module which has different propeller characteristics modeled (the K4 ported but not tuned in that module) so in fact my estimates in the correct simulator model are lower than the ones you measured: 19.8 s with full fuel load, 1.8 ata at 1 Km and 18.5 s at SL.

 

In fact I already published the 19.8 s turn time for the Me-109K4 with full fuel load in this post: 360/18.2=19.8 s so I should have reacted myself when I posted the longer turn time estimates. To excuse myself, the C++ compilator I use has a tab GUI so all it required was to choose the wrong tab.

 

That being said, I still think this is a damn good simulator: However, sometimes things need to be tuned that’s all. However, the jury still seems to be out on that one because as far as I can see you, @HomicideHank and @[TLC]MasterPooner seem to be getting somewhat different results measuring in-game so maybe more testing is needed. However, as you pointed out above, theirs (and my simulations) are done with autumn conditions and yours were I believe done on a summer map and that does impact results.

[Panthera]

1 hour ago, Aurora_Stealth said:

Okay, cheers Hank.

 

We're going to see some differences - as we're using different maps and season setting which will affect temperature and pressure I imagine.

 

Yes, I think the standard we should aim for is the ICAO std. atmosphere (15 deg C, sea level, no wind), 400 L of fuel. That's nice and simple, and allows us to just run the 109 at full fuel.

 

Also we should ofcourse remember to turn on unlimited fuel.

Edited August 24, 2020 by Panthera

[Aurora_Stealth]

No apology required @Holtzauge, any support is appreciated and I don't claim to have all the answers here - just trying to contribute as best as I can with the limited time I have to offer.

 

Yeah I've heard Lapino, (Autumn not Summer) is used as default for testing but unfortunately was only made aware of it after I had started testing. I may do another round of testing on an autumn map later on.

 

I don't wish to be funny (honestly), but one thing I can't understand from that chart you posted is how the P-51 is matching or outperforming the K-4 at the slowest speeds, considering its using a laminar flow wing ... I'd expect this to be the area of greatest weakness for the Mustang.

 

Yeah agree about tuning things, I don't think the game is necessarily miles apart but there is a significant differential somewhere which is causing the reverse to what would be expected - at high altitudes and high speeds its a different story.

Edited August 24, 2020 by Aurora_Stealth

[Panthera]

1 hour ago, Aurora_Stealth said:

I don't wish to be funny (honestly), but one thing I can't understand from that chart you posted is how the P-51 is matching or outperforming the K-4 at the slowest speeds, considering its using a laminar flow wing ... I'd expect this to be the area of greatest weakness for the Mustang.

 

That is because he is using a similar lift coefficient for both, 1.4 for the P-51 and 1.43 for the 109. 

 

I am of the opinion that the 109 has a higher lift coefficient than this however, albeit the difference should be largest power on and at dogfighting speeds. 

 

If you ask me this also ties best with what Skip Holm, Mark Hanna and Dave Southwood have mentioned when comparing these two aircraft, that is the 109 is a much better turning aircraft at slow speeds. Something that wouldn't make sense to say if they were close in this respect.

 

 

Edited August 24, 2020 by Panthera

[JG7_X-Man]

On 8/17/2020 at 5:36 AM, Holtzauge said:

... problem I’m having is that you are making sweeping statements about the benefits of full span slats for Clmax and then applying that to the Me-109 like that was the intention of the designers when they put the slats on the Me-109 evidence for which is still missing as far as I can see.

 

@HoltzaugeInteresting - I will say since the Messerschmitt engineers implemented the idea before the North American engineers, I think they both had the same "intention" regarding the use of slats: Lower stalling speeds (i.e. increasing the aircraft's lift coefficient during low speed maneuvers). 

 

https://www.456fis.org/F-86_SABER.htm

"...It would do no good to build an aircraft capable of high speeds that would be so unstable that it would fall out of the sky at low speeds. The cure for the low-speed stability problem that was worked out by North American engineers was to attach automatic slats to the wing leading edges. The wing slats were entirely automatic, and opened and closed in response to aerodynamic forces. When the slats opened, the changed airflow over the upper wing surface increased the lift and produced lower stalling speeds. At high speeds, the slats automatically closed to minimize drag."

[-=PHX=-SuperEtendard]

About the atmospheric conditions, a good map to test standard atmosphere is Kuban Autumn, which has 15ºC at sea level, and you can fly at sea level in the Black Sea.

The Summer maps have 25ºC at sea level, and the winter maps around -20ºC

Edited August 24, 2020 by -=PHX=-SuperEtendard