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Turning with the P51and tempest vs 109s. Changed on last path??

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Is there anything in the change log indicating that the 109s FM was tweaked for a single patch iteration that lasted what...a day or so? 

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11 hours ago, -[HRAF]Roland_HUNter said:

I would say: RIP 2019.
BF-109 had CL Max 2.0 Sadly we can't see this in the game.(Not suprised me)
https://www.scientistsandfriends.com/aircraft.html

(here the interview what is missing from the website: https://www.youtube.com/watch?v=t5vM4qtQqlM)

 

Wow, that site is full of hot, steaming horsecrap.

The wing-section they're showing for the 109 (slat + flap) holds true for about 5% of it's span.

 

They manage to write "Gustav" wrong, while putting up a performance-table they clearly pulled out of their rear end.

 

 

Quote

The performance of the Me109 and the Spitfire is almost the same.

However, the Spitfire had an average 25%C plain aileron which, despite differential control, gave it a very heavy stick force in roll compared to the light stick force of the Me109.  With a 50% span and narrow chord, Frise, aileron, the Me109 stick forces were very low in roll and it could roll quicker and was more evasive than the Spitfire which was slow in roll.  The control harmony of the Me109 could not be matched by any Allied aircraft in WWII

 

...said noone ever...

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@unreasonable testing with the planes I get around 1.75 for the 109 and 1.5 for the P-51. At 1000 meters in level flight I cut throttle and try to mantain altitude until one wing drops, note the speed, convert it to TAS and use your calculator, I am not fixing the AoA though as I increase it as the plane gets slower, eventually stalling out. Is my procedure correct or should I do it differently? 

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Are you testing flaps and gear up or down? Personally, reviewing my tests from years ago using a similar approach made me think I overestimated clmax, because it was very hard to maintain 1g down to the split second where you stall. You only need to lose a couple of meters of altitude in the last seconds and that means +0.2 clmax.

 

For what it's worth, I know of Messerschmitt figures ranging from 1.13 to 1.95 for clmax for the Bf109, depending on submodel, configuration, power and speed.

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3 hours ago, Bremspropeller said:

 

Wow, that site is full of hot, steaming horsecrap.

The wing-section they're showing for the 109 (slat + flap) holds true for about 5% of it's span.

 

They manage to write "Gustav" wrong, while putting up a performance-table they clearly pulled out of their rear end.

...

 

It gets worse. Whoever is behind that website thinks the Germans had "anti-gravity":  https://www.scientistsandfriends.com/about.html

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Well, they say the Germans discovered it and honestly, I am anti-gravity occasionally, but so far all my complaints went unanswered. I always had to pick up whatever I just dropped.

Edited by JtD
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23 minutes ago, AndyJWest said:

 

It gets worse. Whoever is behind that website thinks the Germans had "anti-gravity":  https://www.scientistsandfriends.com/about.html

Sry bro I don't care about CCCP opinion, I care about documents ;)
Who wrote that, was a pilot who flew the 109, then the second is a real german document.

So your sarcastic comment is nothing to do with it.
Next time please send me info about the topic.

3 hours ago, Bremspropeller said:

 

Wow, that site is full of hot, steaming horsecrap.

The wing-section they're showing for the 109 (slat + flap) holds true for about 5% of it's span.

 

They manage to write "Gustav" wrong, while putting up a performance-table they clearly pulled out of their rear end.

 

 

 

...said noone ever...

Are you flew with 109?
Because your  sturdiness in your  comment looks like you did.
If not, and you have no counter document about this. Then please keep in yourself  your opinion.

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Random graphs on websites created by idiots aren't 'documents'. Cite the original source. 

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4 hours ago, Pre said:

Is there anything in the change log indicating that the 109s FM was tweaked for a single patch iteration that lasted what...a day or so? 

 

No, there is nothing. 

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1 hour ago, JtD said:

Are you testing flaps and gear up or down? Personally, reviewing my tests from years ago using a similar approach made me think I overestimated clmax, because it was very hard to maintain 1g down to the split second where you stall. You only need to lose a couple of meters of altitude in the last seconds and that means +0.2 clmax.

 

For what it's worth, I know of Messerschmitt figures ranging from 1.13 to 1.95 for clmax for the Bf109, depending on submodel, configuration, power and speed.


Flaps and gear up, idle throttle. Yeah the last seconds it's hard to keep it constant, didn't know it could induce so much error.

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Gotta love the latest release and especially the P-51 which is absolutely lovely and my new favourite ride! :good:

 

Anyway, concerning the relative turn rate between the different planes it’s a lot to do about the assumed boost and weight of course and IMHO the Pony should not be penalized for a high internal fuel capacity so I assumed the same fuel load for the Me-109K4 and P-51D in the attached C++ simulation chart I did a few years back.

 

As can be seen, even at full internal fuel and even at 1.8 ata the K4 beats a Pony with a similar amount of fuel. Also interesting is how much better the K4 is at 8 Km.

 

IIRC then if you decrease the P-51 down to 67” boost (i.e. translate the right hand part of the P-51 curve down at bit) then the C++ simulation indicates that the Dora and Pony are pretty evenly matched in terms of turn rate but the P-51 will do it at a lower speed than the Dora.

 

However, when it comes to the stationary turn rate the K4 should have a slight advantage even at 1.8 ata so at 1.98 ata the difference will be even bigger with the right hand part of the K4 curve translated up to the right.

 

1780827500_P51DFw190D9Me109K4stationaryturnratePAFPA49.JPG.477d9d60771314a60404fcadd11333e4.JPG

 

 

 

 

 

 

Edited by Holtzauge
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@Holtzauge thanks for the info ^^ Tried to replicate it in game at 1km and roughly 320 km/h tas. And I get roughly 17.5 degrees/s with the K-4 and 18,5 degrees/s with the P-51 at the same conditions. That being said it is not so easy to mantain the constant speed/alt so there is some error to it.

Edited by -=PHX=-SuperEtendard

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Can someone clear something up for me? Is Clmax actually directly relevant when discussing maximum sustained turn rates in WW2 fighters? As I understood it, the limit on sustained turn is power, rather than lift - if you are at best turn speed you can generally increase the AoA without stalling, but will then slow down. 

Edited by AndyJWest

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1 hour ago, -=PHX=-SuperEtendard said:

@Holtzauge thanks for the info ^^ Tried to replicate it in game at 1km and roughly 320 km/h tas. And I get roughly 17.5 degrees/s with the K-4 and 18,5 degrees/s with the P-51 at the same conditions. That being said it is not so easy to mantain the constant speed/alt so there is some error to it.

 

OK, interesting that the P-51 is better. How much fuel (%) did you use in the test? Is there a way to get the exact weights you had in test (all up) because that is what I use in the simulation.

1 hour ago, AndyJWest said:

Can someone clear something up for me? Is Clmax actually directly relevant when discussing maximum sustained turn rates in WW2 fighters? As I understood it, the limit on sustained turn is power, rather than lift - if you are at best turn speed you can generally increase the AoA without stalling, but will then slow down. 

 

Both Clmax and power can get you a higher sustained turnrate: If you take any of the figures I posted above, increasing Clmax translates the left hand part of the curve up to the left, i.e. better turnrate at lower speeds (right hand curve stays in place) while keeping Clmax constant and getting more power keeps the left hand part of the curve in place while the right hand part gets moved up to the right, i.e. higher turn rate at higher speed. So the plane is at Clmax at the apex of the curve.

Edited by Holtzauge
Added "sustained"
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39 minutes ago, Holtzauge said:

 

OK, interesting that the P-51 is better. How much fuel (%) did you use in the test? Is there a way to get the exact weights you had in test (all up) because that is what I use in the simulation.

 

 

According to the in game specs, for the K-4 the total weight was 3361 Kg (400 liters of fuel), power 1.8 ata, for the P-51 the weight was 4134 Kg (also 400 liters of fuel) power 75" 3000 RPM.

I also got some other numbers at sea level and slower speeds in one of my previous posts if you want to check them with your simulation:

This is for around 280 km/h and sea level (20-30 meters):

For the K-4 at the same 3361 Kg, 1.8 ata: 19,05 degrees/s

Bf 109 G-14 3266 Kg (400 liters of fuel) 1.7 ata: 19,78 degrees/s

P-51D-15 4343 Kg (690 liters of fuel) at 67": 17,91 degrees/s

P-51D-15 4170 Kg (450 liters of fuel) at 75": 20 degrees/s

The P-51 and Bf 109 are in clean condition, without wing/fuselage bomb racks.

Edited by -=PHX=-SuperEtendard
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1 hour ago, -=PHX=-SuperEtendard said:

thanks for the info ^^ Tried to replicate it in game at 1km and roughly 320 km/h tas. And I get roughly 17.5 degrees/s with the K-4 and 18,5 degrees/s with the P-51 at the same conditions. That being said it is not so easy to mantain the constant speed/alt so there is some error to it.

Thats not what I get, at least relatively. Ive done it over and over now and I get 19.5deg/sec  a second for a 25% mustang and 50% 109. (150 for 51). I have not done a test yet where the 51 could out turn the 109 in il2gb.

 

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9 minutes ago, YIPPEE said:

Thats not what I get, at least relatively. Ive done it over and over now and I get 19.5deg/sec  a second for a 25% mustang and 50% 109. (150 for 51). I have not done a test yet where the 51 could out turn the 109 in il2gb.

 


Was it also at 1000 meters altitude in the Kuban Autumn map (standard atmosphere)? The 19.5 deg/sec looks closer to my sea level results, though you are using less fuel. I can tell it can vary depending on the ability of each one to hold the the turn the best way possible, which I don't claim I'm perfect at 😅. A hold altitude/hold speed autopilot command would be handy for these tests.

But we can agree the planes are rather similar, a close maneuvering fight will depend more on the skill of each pilot rather than the turn performance of the planes, unlike Spit vs 190 or Zero vs P-40.

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28 minutes ago, -=PHX=-SuperEtendard said:

 

According to the in game specs, for the K-4 the total weight was 3361 Kg (400 liters of fuel), power 1.8 ata, for the P-51 the weight was 4134 Kg (also 400 liters of fuel) power 75" 3000 RPM.

I also got some other numbers at sea level and slower speeds in one of my previous posts if you want to check them with your simulation:

This is for around 280 km/h and sea level (20-30 meters):

For the K-4 at the same 3361 Kg, 1.8 ata: 19,05 degrees/s

Bf 109 G-14 3266 Kg (400 liters of fuel) 1.7 ata: 19,78 degrees/s

P-51D-15 4343 Kg (690 liters of fuel) at 67": 17,91 degrees/s

P-51D-15 4170 Kg (450 liters of fuel) at 75": 20 degrees/s

The P-51 and Bf 109 are in clean condition, without wing/fuselage bomb racks.

 

OK, thanks for the info. I can't run the numbers today but tomorrow evening after work CET I will do a simulation with those numbers and see how that pans out. I think the comparison I did was originally to compare the Dora and Pony and that the K4 was added later at full fuel load which is more like 296 Kg according to Kennblatt but without the MW50 which adds another 63 Kg for a total of 359 Kg which is close but not quite 388 Kg the rationale for which now escapes me 5 years later......

Edited by Holtzauge
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5 minutes ago, -=PHX=-SuperEtendard said:


Was it also at 1000 meters altitude in the Kuban Autumn map (standard atmosphere)? The 19.5 deg/sec looks closer to my sea level results, though you are using less fuel. I can tell it can vary depending on the ability of each one to hold the the turn the best way possible, which I don't claim I'm perfect at 😅. A hold altitude/hold speed autopilot command would be handy for these tests.

But we can agree the planes are rather similar, a close maneuvering fight will depend more on the skill of each pilot rather than the turn performance of the planes, unlike Spit vs 190 or Zero vs P-40.

I forgot about the 1000m. Very hard to manually test anything other than sea level due to altitude gain and loss. I dont think and could do it!

 

I tested again at same power, sea level with fuel levels from the chart. I got 18.5 for 109 and 17.5 for 51.

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3 hours ago, Holtzauge said:

Gotta love the latest release and especially the P-51 which is absolutely lovely and my new favourite ride! :good:

 

Anyway, concerning the relative turn rate between the different planes it’s a lot to do about the assumed boost and weight of course and IMHO the Pony should not be penalized for a high internal fuel capacity so I assumed the same fuel load for the Me-109K4 and P-51D in the attached C++ simulation chart I did a few years back.

 

As can be seen, even at full internal fuel and even at 1.8 ata the K4 beats a Pony with a similar amount of fuel. Also interesting is how much better the K4 is at 8 Km.

 

IIRC then if you decrease the P-51 down to 67” boost (i.e. translate the right hand part of the P-51 curve down at bit) then the C++ simulation indicates that the Dora and Pony are pretty evenly matched in terms of turn rate but the P-51 will do it at a lower speed than the Dora.

 

However, when it comes to the stationary turn rate the K4 should have a slight advantage even at 1.8 ata so at 1.98 ata the difference will be even bigger with the right hand part of the K4 curve translated up to the right.

 

1780827500_P51DFw190D9Me109K4stationaryturnratePAFPA49.JPG.477d9d60771314a60404fcadd11333e4.JPG

 

 

Great stuff once more Holtzauge!:good:

 

I am getting slightly different results than you (my P-51 curve is slightly more to the right, and infront of the K4 instead of behind it), but I'm sure that's down to using a different CLmax for the P-51 & Dora. That said again your C++ simulation is matching my curves so beautifully, and I really have to commend you for your work on it, wish I had such a tool myself and didn't have to do each parameter at a time :)

 

Awesome as always!

Edited by Panthera
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8 hours ago, Bremspropeller said:

 

Wow, that site is full of hot, steaming horsecrap.

The wing-section they're showing for the 109 (slat + flap) holds true for about 5% of it's span.

 

They manage to write "Gustav" wrong, while putting up a performance-table they clearly pulled out of their rear end.

 

 

 

...said noone ever...

Also what is this lol chart. Like what....even...is this. 1941 G? 419mph! only 3300fpm? P-51 395mph? 1700fpm? WAT.

 

image.png.28b0ba8210e391cc627dc345acdcbb07.png

Edited by YIPPEE
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21 hours ago, YIPPEE said:

Except they are not compared at similar altitudes. The altitudes are all over the place. And there isnt a single chart in that report comparing them at low altitudes. Additionally, the F6F is the main one with an advantage. The P-38 wing, which is also a conventional airfoil, shows no advantage at all. And the bottom line is that at lower altitudes and lower mach numbers the CL is 1.4. And at low alts and low mach numbers the 109s was 1.4. Pointing out the relationship to certain other airfoils does nothing to change that.

 

 

Look at the graph from the report you posted yourself, there are curves for 25 kft there as well, and the trend is the same, the laminar flow airfoil produces less lift until above 0.5 Mach.

 

Also keep in mind that all these Clmax figures we've been quoting are with power off or at idle, where'as the 109's real advantage comes with power on where prop wash is energizing the inner wing section allowing it to match the outer slatted section in lift generation and thus providing for a significant net gain in lift.

With power off the 109's root section would stall first whilst the outer section is still flying due to the slats, and as such the net gain will be much smaller here.

 

i.e. with power off the outboard slatted wing should demonstrate a similar to slightly higher Clmax than the unslatted one, but with power on the difference should be significant.

Edited by Panthera

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17 minutes ago, Panthera said:

 where'as the 109's real advantage comes with power on where prop wash is energizing the inner wing section allowing it to match the outer slatted section in lift generation and thus providing for a significant net gain in lift.

The big assumption here is that the increase to the inner wing would match the outer slatted section. Additionally this is not the conclusion that the dcs devs, holtzauge, or the il2 devs came to. There is an entire thread on the dcs forums explaining why the slats on the 109 do not provide this big benefit.

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2 hours ago, Holtzauge said:

Both Clmax and power can get you a higher sustained turnrate: If you take any of the figures I posted above, increasing Clmax translates the left hand part of the curve up to the left, i.e. better turnrate at lower speeds (right hand curve stays in place) while keeping Clmax constant and getting more power keeps the left hand part of the curve in place while the right hand part gets moved up to the right, i.e. higher turn rate at higher speed. So the plane is at Clmax at the apex of the curve.

 

Thanks. Yes, that makes sense.

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Just subjective observation here, do with it what you will:  

 

QMB:   P-51 vs. 109 G6  (1v1)  

Settings: 50% fuel, 150oct, extra ammo

Difficulty:  unlimited ammo, all other realistic.

Ai difficulty: random

Enemy waves: until ammo out.

 

After multiple fights I did see that the G6 did, in fact have the ability to out-turn me and could even try to force head-on passes.  

If the P-51 got below 200mph there was a serious chance of being tailed with no escape.

However, if I kept the speed up and flew to achieve more advantageous flight path angles, not trying to directly follow from a distance, the G6 was hopeless. 

After getting directly onto the G6's tail at close range, applying the 10 degrees flap setting and the appropriate power, there was nothing it could do but try to make me waste ammo. 

 

Most of these fights started with me being low and slow from shooting down the last enemy, with the next less than 10km away from 1500m alt., to me being able to evade long enough to pretty systematically gaining the altitude and angle advantage. 

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7 hours ago, -=PHX=-SuperEtendard said:

@unreasonable testing with the planes I get around 1.75 for the 109 and 1.5 for the P-51. At 1000 meters in level flight I cut throttle and try to mantain altitude until one wing drops, note the speed, convert it to TAS and use your calculator, I am not fixing the AoA though as I increase it as the plane gets slower, eventually stalling out. Is my procedure correct or should I do it differently? 

 

Hi - not ignoring you: out for birthday dinner last night!

 

The figures I gave were not from testing, just using the numbers from the data tab in the game. Presumably these will be added to the tech specs page in due course.

Stall speed in flight configuration is given as a range, so I use the low end number with the minimum operating weight, and the top end number with the maximum take off weight. I assume IAS = TAS, ie the tests were at sea level. Game instruments have no PEC or AoA errors.

 

Testing this in game is always tricky as JtD points out: IIRC Han has said that the game numbers provided were produced using a robot, so I assume they are consistent between tests. 

 

The P-51 came about where I expected it but not the Tempest. Given that anyone with any sense will be keeping the speed up in a Tempest, and given @Holtzauge's explanation of the effects of CLmax and power on the turn rate chart, the Tempst's low stall speed may not have much effect in fighting, but it does look odd.  

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22 hours ago, AndyJWest said:

Can someone clear something up for me? Is Clmax actually directly relevant when discussing maximum sustained turn rates in WW2 fighters? As I understood it, the limit on sustained turn is power, rather than lift - if you are at best turn speed you can generally increase the AoA without stalling, but will then slow down. 

 

Not so much.   Which begs the question... why so much discussion about CLmax?   It only roughly shows max lift potential at max alpha, and approximate stall speed.  It doesn't really tell you happens at typical maneuvering angles.

 

At the moderate alphas you are most often turning in combat, including in sustained turns, excess power is much more important as you state - excess power being thrust minus drag.   I don't agree with anyone that says a mustang wing is inefficient in a turn compared to a conventional airfoil, because it doesn't achieve some improved degree of 'laminar-ness'.     It's a very low drag wing that produces as much lift as moderate angles as anything else.   The low drag wing, low drag airframe and cooling system, and class matching power, produce a very good maneuvering aircraft if you keep your speed up.

 

Edited by Barfly

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21 hours ago, -=PHX=-SuperEtendard said:

 

According to the in game specs, for the K-4 the total weight was 3361 Kg (400 liters of fuel), power 1.8 ata, for the P-51 the weight was 4134 Kg (also 400 liters of fuel) power 75" 3000 RPM.

I also got some other numbers at sea level and slower speeds in one of my previous posts if you want to check them with your simulation:

This is for around 280 km/h and sea level (20-30 meters):

For the K-4 at the same 3361 Kg, 1.8 ata: 19,05 degrees/s

Bf 109 G-14 3266 Kg (400 liters of fuel) 1.7 ata: 19,78 degrees/s

P-51D-15 4343 Kg (690 liters of fuel) at 67": 17,91 degrees/s

P-51D-15 4170 Kg (450 liters of fuel) at 75": 20 degrees/s

The P-51 and Bf 109 are in clean condition, without wing/fuselage bomb racks.

 

OK, so here are the numbers for sea level I get in my C++ simulation. I use standard atmosphere 15 deg C and IIRC then you use the autumn map right? If that is so then we are comparing same conditions.

 

I'm really surprised with how good Il-2 is: My C++ simulations run pretty quick (takes 5-10 s to get the numbers on i7 4 core 3.4 GHz) but in BoB all this is being done in real time so once again we can see what a good simulator this is! The level of accuracy is simply outstanding. When I started off doing these comparisons between my C++ models and the state of the art flight simulators more than 10 years ago the level of accuracy was nowhere near as good as this is.  We can be very happy with what we are getting for our money. :good:

 

I post both the results for the speeds you tested at and also what the simulation thinks are the optimum speeds for best turnrate.

 

For the K-4 at the same 3361 Kg, 1.8 ata:  280 Km/h 18.1 degrees/s, at 310 Km/h 19.3 degrees/s

Bf 109 G-14 3266 Kg (400 liters of fuel) 1.7 ata: 280 Km/h 18,7 degrees/s, at 300 Km/h 20.0 degrees/s

P-51D-15 4343 Kg (690 liters of fuel) at 67": 280 Km/h 17,2 degrees/s, at 273 Km/h 17.3 degrees/s

P-51D-15 4170 Kg (450 liters of fuel) at 75": 280 Km/h 19,0 degrees/s, at 286 Km/h 19.2 degrees/s

 

 

Edited by Holtzauge
Updated K4 and speeds for best turn rate which were wrong in first post
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1 hour ago, unreasonable said:

@Holtzauge do you have time to put the Tempest through your program?  

 

Sure, IIRC I have both +9 and +11 boost modeled so if you give me the weight I can do it after work today.

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Tempest Mk5 turn performance simulated in my C++ program yields these results at +11 boost sea level +15 deg C standard atmospheric conditions:

 

W=5221 Kg  best turn speed 293 Km/h gives turn rate 19.8 deg/s

W=4974 Kg (400 l fuel) best turn speed 299 Km/h gives turn rate 20.8 deg/s

 

@-=PHX=-SuperEtendard, Do you think you could test the Tempest in-game like you did the other planes for a comparison?

 

I think it was mentioned that the in-game Tempest currently has a Clmax of 1.75 modeled? Just out of curiosity and since the effect of Clmax has been discussed I did a run with this and while the best turn rate does not go up that much it turns out that you can keep a very high stationary turnrate down to very low speeds, all the way down to 230 Km/h in fact, which reduces the turn radius by a lot and gives you the option to cut a very tight corner inside someone's turn without loosing speed:

 

W=4974 Kg (400 l fuel) and Clmax=1.75 best turnrate pretty flat at 21.7 deg/s from 290 Km/h all the way down to 230 Km/h.

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6 hours ago, Holtzauge said:

Tempest Mk5 turn performance simulated in my C++ program yields these results at +11 boost sea level +15 deg C standard atmospheric conditions:

 

W=5221 Kg  best turn speed 293 Km/h gives turn rate 19.8 deg/s

W=4974 Kg (400 l fuel) best turn speed 299 Km/h gives turn rate 20.8 deg/s

 

@-=PHX=-SuperEtendard, Do you think you could test the Tempest in-game like you did the other planes for a comparison?

 


I did ^^  For the Tempest at sea level, 5221 Kg, +11 boost and roughly 280 km/h I got 19.35 deg/s, with the radiator shutter in the open position. What's the value you use for Clmax? Looks like it is hard to find that parameter for the plane.

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10 hours ago, Holtzauge said:

Tempest Mk5 turn performance simulated in my C++ program yields these results at +11 boost sea level +15 deg C standard atmospheric conditions:

 

W=5221 Kg  best turn speed 293 Km/h gives turn rate 19.8 deg/s

W=4974 Kg (400 l fuel) best turn speed 299 Km/h gives turn rate 20.8 deg/s

 

@-=PHX=-SuperEtendard, Do you think you could test the Tempest in-game like you did the other planes for a comparison?

 

I think it was mentioned that the in-game Tempest currently has a Clmax of 1.75 modeled? Just out of curiosity and since the effect of Clmax has been discussed I did a run with this and while the best turn rate does not go up that much it turns out that you can keep a very high stationary turnrate down to very low speeds, all the way down to 230 Km/h in fact, which reduces the turn radius by a lot and gives you the option to cut a very tight corner inside someone's turn without loosing speed:

 

W=4974 Kg (400 l fuel) and Clmax=1.75 best turnrate pretty flat at 21.7 deg/s from 290 Km/h all the way down to 230 Km/h.

 

I gave the 1.75 (1.746) number.  It comes from wing area 27.81m^2 and stall speed of 140kph, at minimum operational weight of 4585kg. If you use the upper range of the stall speeds - 163 kph - with the maximum take-off weight you 6190kg get 1.74  (1.739)

 

The numbers given in the manual are 85 mph IAS at 11,500lbs. ie 137kph @ 5216kg. That is CLmax of 2.08

 

These are some of the lowest stall speeds in the game: lower than the Spitfire IX.  The single seat fighter with the next highest minimum weight CLmax in the game is the MC.202 at 1.42

 

If you use figures from the manual to calculate CLmax for Spitfire I, Vb and P40E you also get numbers in the 2.00 area: but in game the developers have given us  stall speeds ~15-20% higher. I believe that is because they were aware of the RAE report about speed measurement errors in the Spitfire, but I do not recall seeing an explicit explanation.

 

 


 

 

 

 

 

 

 

 

 

 

 

 

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17 hours ago, -=PHX=-SuperEtendard said:


I did ^^  For the Tempest at sea level, 5221 Kg, +11 boost and roughly 280 km/h I got 19.35 deg/s, with the radiator shutter in the open position. What's the value you use for Clmax? Looks like it is hard to find that parameter for the plane.

 

OK, so basically identical results. I use Clmax=1.35 for the Tempest in the C++ model.

13 hours ago, unreasonable said:

 

I gave the 1.75 (1.746) number.  It comes from wing area 27.81m^2 and stall speed of 140kph, at minimum operational weight of 4585kg. If you use the upper range of the stall speeds - 163 kph - with the maximum take-off weight you 6190kg get 1.74  (1.739)

 

The numbers given in the manual are 85 mph IAS at 11,500lbs. ie 137kph @ 5216kg. That is CLmax of 2.08

 

These are some of the lowest stall speeds in the game: lower than the Spitfire IX.  The single seat fighter with the next highest minimum weight CLmax in the game is the MC.202 at 1.42

 

If you use figures from the manual to calculate CLmax for Spitfire I, Vb and P40E you also get numbers in the 2.00 area: but in game the developers have given us  stall speeds ~15-20% higher. I believe that is because they were aware of the RAE report about speed measurement errors in the Spitfire, but I do not recall seeing an explicit explanation.

 

Well if that is the Clmax clean wing then 1.75 is way to high. With some angle on the flap then sure but clean wing no way. Probably has to do with the IAS position error just like on the P-40 and Spitfire and the manual stating what you would see in the cockpit and not the actual calibrated speed. I recall some rather heated forum discussions about this (position error being a thing or not at stall speeds) a while back...... ;)

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52 minutes ago, Holtzauge said:

 

OK, so basically identical results. I use Clmax=1.35 for the Tempest in the C++ model.

 

 

There is something strange, because I get a stall speed of around 143 km/h at idle throttle with 5221 Kg, and apparently IL-2 doesnt take into account pitot errors, so in theory that would translate to a Clmax of around 1.9 but it doesnt seem to show in the turn performance. 

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5 minutes ago, -=PHX=-SuperEtendard said:

 

There is something strange, because I get a stall speed of around 143 km/h at idle throttle with 5221 Kg, and apparently IL-2 doesnt take into account pitot errors, so in theory that would translate to a Clmax of around 1.9 but it doesnt seem to show in the turn performance. 

 

It did not show in my simulations either (using 1.35 or 1.75) in terms of getting a better turn rate figure. What it did do was to extend the speed range in which I could get the max turn rate down to really low numbers. Have you tried going slower? Like at 250 Km/h IAS SL? What turn rate do you get at those speeds?

Edited by Holtzauge

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