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What to expect from the new flightmodels
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Author:  Robert [ Sun Aug 20, 2017 4:42 am ]
Post subject:  What to expect from the new flightmodels

<S> all!
I thought I'd share with you what is different in the way we try to program the new flightmodels compared to how they have been modeled previously in Warbirds. This so that all customers know what they can expect when flightmodels get a fresh rehaul. For one we now put a lot of time and research into each airplane, trying to get everything as correct as possible with the data we can find. This is sometimes a hard task as data from different sources can show very different numbers, and we try to discuss this until we agree on which data that seems most logical. We try to work as a team where everyone's opinion has equal value. Also there is no "let's just get done with this flightmodel and move on to the next" thinking. Every airplane is allowed to take the time it needs to get finished, and if performance issues are found after an update, like the current P-47D's climb rate being to high, then it will be retweaked again for the next update. I for one really hope we can give you as historically accurate flightmodels as possible, and we are always listening to feedback and opinions that can be backed up by real facts and data.

Major differences in flightmodeling.

Max AoA
A big difference is that we now first put time into finding the correct max Angle of attack for each airplane. This determines at what an angle you can turn against the airflow without the wing stalling. Previously max AoA was usually set at 18-22 degrees, but now most airplaines will have a more historical max AoA of 14-17 degrees. We try to use data from sites such as:
http://naca.central.cranfield.ac.uk/rep ... rt-829.pdf
http://airfoiltools.com/airfoil/details ... 51droot-il
http://m-selig.ae.illinois.edu/ads/aircraft.html

Wing efficiency (Oswald factor)
This is probably the most major difference in how flightmodels will now be programmed. The wing efficiency factor is quite dependent on a wing's liftco, wingspan and induced dragco relation. Previously the induced dragco was often just used as a random slap-on parameter to adjust the climb rate of a fighter. (quick info about induced dragco: https://www.grc.nasa.gov/www/k-12/airplane/induced.html).
As a consequence some airplanes have turned out as "UFO's" while others have been considered as "hogs" by the community. After much testing I found that the induced dragco vs liftco correlation heavily affects an airplane's E-bleed in Warbirds. As this parameter has just been set arbitrarily until now, it very much explains why some fighters can flip around like crazy without losing their energy while others seem to fall out of the sky whenever making a simple turn.

Luckily Idunno and Bcamel have been able to share much of their knowledge on this subject, and the Wing efficiency factor (Oswald factor) is a way to measure how effective a wingshape is in reality vs if there wasn't any induced turbulence. For a truly eliptical wing this would be 100%, but in real life for a Spitfire or P-47 this is rather ~90% due to twists in the wingshape. The majority of ww2 fighters should have a wing efficiency factor of 75-85%. When giving a flightmodel a rehaul the new FM Team now first tries to determine this factor for the airplane before modeling the engine etc. We do this at the best of our ability, looking at wing shape, twists, aspect ratio etc. For all new flightmodels this will generally be set to in between 75-90 %. As such our new flightmodels will usually be better at retaining their energy than they previously were. This can be used to your advantage by more effectively performing climbing combat turns or better retaining speed while boom n zoom fighting etc, or it might force you to temporarily reduce the throttle if you want to tighten the turn when entering a turn fight at to high initial energy.

I just did a check-up of all fighters and the old models are very arbitrary modeled. I wasn't surprised to find out that the most popular models like the Spitfires, Bf 109's, F4U's, P-38's etc have a wing efficiency of 60-70%, while fighters that no one ever flies, like the Lavochkin La7, Mosquitos, Macchi C.205 etc, currently have a terrible wing efficiency of 30-40%. In real life such a mediocre wingdesign would never even have passed the drawingboard stage and it's no wonder that these planes are considered as hogs by the community.

Stall speed
The stall speed is now also set and tested at an early stage in the FM building process, and we always spend time pinpointing this by searching for historical data and logical puzzling by looking at airfoil thickness ratio, wingloading, wingshape etc when data is missing or seems suspicious. We find it vital to have a correct stall speed in order for the fighter to get a historical dogfight performance.

Realistic flaps
The flightmodels retweaked during the last few years were given a liftco four times as high as realistic data when using combat flaps. Also the liftco didn't scale with increasing flaps angle. As such around half of the fighters, like the A6M Zeros, gained a normal 3-5 mph stall speed reduction at combat flaps, while fighters like the Bf 109's reduced their stall speed by a whooping 10-20 mph. These FM's were quick-fixed in the last update though and all newly rehauled flightmodels will have a flaps performance based on historical data and calculations regarding added liftco, dragco etc.

Other performance
We do our best to have the new flightmodels perform even more accurately according to historical data regarding top speed, climb rate, fuel consumption, weight, stability in different axes, control effectiveness at various speed etc than before. The above subjects are probably the largest differences in what people can expect from our new fighters though from a pure gameplay perspective. Also once done with all flightmodels there should hopefully be no more UFO's, like the previous La5FN which could outfight it's adversaries while flying upside down, while the P-47 tumbled down from performing a simple 180° turn, or Mosquitos that now can barely even take-off with bombs. We hope the fighters will soon match-up against eachother like they would in real life, and even more importantly that they will all abide to the the same laws of physics.


Flightmodels rehauled by the new FM Team so far:
Fw 190A-1, Fw 190A-2, Fw 190A-4, Fw 190A-8, Fw 190F-8, Fw 190D-9
P-51D, P-51B, Mustang MkI, A-36
P-47D-25, P-47D-22, P-47C

Next update - Complete rehauls for the:
Lavochkin La5F, La5FN, La7's
Yak-9D and Yak-3
Also climb rate fix for the P-47's
Climb rate fix for the Fw 190's when using the MW50 injection WEP

Subsequent update - Complete rehauls for the:
Brewster Buffalo F2A-3, B339 and B239
Fokker D.XXI
MiG-3
I-16 "Ishak"

Future updates
To be decidied


<S> and see you all in the virtual skies! :D

Author:  bollok [ Sun Aug 20, 2017 5:38 am ]
Post subject:  Re: What to expect from the new flightmodels

Good to see some progress.

Many may not understand the significance but in really simple terms consider the spitfire and hurricaine.

The Hurricaine has a thicker wing that can fly at higher AOA than the Spit.
But the higher the AOA, the worse the drag penalty.

What this means in real terms is that the Hurricaine can pull its nose around a little more and therefore always "turn inside" the spitfire. This is instantaneous turn.
However the higher AOA also means more speed reducing drag, so the Hurri cannot maintain this higher AOA for very long without speed bleeding off rapidly.

Now lets consider the 109 with its leading edge slats.
The wing operated at lower AOA than the spitfire however, with the slats automatically deployed - it allowed the wing to temporarily operate at higher AOA (similar to the spit)

The conjecture is that the leading edge slats were off putting to many LW pilots and its likely that not all were able to get the best out of this aircraft.
But many maintain they could turn with a spit.

Author:  mSpiro [ Mon Aug 21, 2017 11:30 am ]
Post subject:  Re: What to expect from the new flightmodels

Thanks for time and effort guys. <S>s

Author:  olddog [ Mon Aug 21, 2017 1:23 pm ]
Post subject:  Re: What to expect from the new flightmodels

that sounds great, keep at it.

Author:  juice= [ Sun Sep 03, 2017 7:51 pm ]
Post subject:  Re: What to expect from the new flightmodels

(S) Robert

The time spent to make clear not only what has been done but the underpinnings about its process and the goals in doing so are enough for praise.
But, this is only the end of much more work to arrive at the explanation.

Thank you and of course so many others for the hard work.....excellent.

Juice

Author:  Robert [ Tue Sep 12, 2017 6:07 am ]
Post subject:  Re: What to expect from the new flightmodels

Thank you, sir! Doing our best one fighter at a time, and oftentimes it's pretty fun to do the modeling and see the results :D


Cheers!
/Robert

Author:  onisan [ Tue Sep 19, 2017 5:52 am ]
Post subject:  Re: What to expect from the new flightmodels

Cudos for all your work guys, hanging in there for a while now.
Nice to see things improve!

Cheers
Oni

Author:  grumpy [ Tue Sep 19, 2017 10:41 am ]
Post subject:  Re: What to expect from the new flightmodels

onisan,

Robert is now working on the Japanese set of aircraft. Hope you hang around until their done, so you get to give them a go.

<S>

Author:  Robert [ Tue Sep 19, 2017 3:01 pm ]
Post subject:  Re: What to expect from the new flightmodels

Yes sir, currently working on the Zeros and almost have them finished. Will also soon begin work on the N1K1. The A6M's are looking good so far, hitting real world data very nicely. It's also nice to see that as an effect of modeling them by realistic parameters, with a more correct stall speed, engine setup and wing efficiency, they seem to be very good turn fighters. They'll be better than the current models are. The new Zeros and Wildcats should be out in around 1.5 month, after the Macchi series. :)

Below is a comparison between the speed and climb of the Zeros I'm currently modeling, the A6M5 vs ww2 data, as well as their turn performance at sea level vs the other early war fighters I've been working on so far.


Image Image

Image Image


Image

Author:  -sakai [ Tue Sep 19, 2017 3:21 pm ]
Post subject:  Re: What to expect from the new flightmodels

Robert wrote:
Yes sir, currently working on the Zeros and almost have them finished. Will also soon begin work on the N1K1. The A6M's are looking good so far, hitting real world data very nicely. It's also nice to see that as an effect of modeling them by realistic parameters, with a more correct stall speed, engine setup and wing efficiency, they seem to be very good turn fighters. They'll be better than the current models are. The new Zeros and Wildcats should be out in around 1.5 month, after the Macchi series. :)

Below is a comparison between the speed and climb of the Zeros I'm currently modeling, the A6M5 vs ww2 data, as well as their turn performance at sea level vs the other early war fighters I've been working on so far.


Image Image

Image Image


Image


Well done, Sir. Looking forward to this.

Tell me...what was the verdict from the FM team on the SAKAE 12 carburetor?

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