Advanced Flight Model for other aircrafts!
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Hello there Mav,
First of all i’m sorry for making you people wait so much for the data that i promised to share and worked on!
Thank you for the reply regarding the engines thrust values, which now i understand why they weren’t the values at Mach=0, alt=0. This also explains why my MIG-23, MIG-21 and F-4E which i worked on, did seem to accelerate a bit more than the manual says! So now i have my answer and i’ll begin to rework them as soon as possible. I’m very glad to hear that with those thrust values, the F-16C accelerates (within the given conditions of air density, weight and airspeed) in a par with the real one, so now i have a good reference point for my further work on the F-4E, MIG-21 and MIG-23, which i want to finish.
I’ll try to upload the 4 files now, let’s hope this time it works, because i’m still getting the “invalid file” error when i try to upload a file (from my computer or url) using the attachment function!
The F-4E: http://speedy.sh/td5gD/f4e.dat
The MIG-21: http://speedy.sh/PExjv/mig21.dat
The MIG-23ML: http://speedy.sh/6Mzbn/mig23.dat
MIG-23ML’s AFM test: http://speedy.sh/mHuGN/mig23-afm.dat
I’m not too used with file upload servers so far, so if the above aren’t easy to access, try the following:
http://www.fileconvoy.com/dfl.php?id=gf2d3c0e6c6644f66999347860ab5844ad6b9be9c6
Have a good day!:-)
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Hello there Mav,
First of all i’m sorry for making you people wait so much for the data that i promised to share and worked on!
Thank you for the reply regarding the engines thrust values, which now i understand why they weren’t the values at Mach=0, alt=0. This also explains why my MIG-23, MIG-21 and F-4E which i worked on, did seem to accelerate a bit more than the manual says! So now i have my answer and i’ll begin to rework them as soon as possible. I’m very glad to hear that with those thrust values, the F-16C accelerates (within the given conditions of air density, weight and airspeed) in a par with the real one, so now i have a good reference point for my further work on the F-4E, MIG-21 and MIG-23, which i want to finish.
I’ll try to upload the 4 files now, let’s hope this time it works, because i’m still getting the “invalid file” error when i try to upload a file (from my computer or url) using the attachment function!
The F-4E: http://speedy.sh/td5gD/f4e.dat
The MIG-21: http://speedy.sh/PExjv/mig21.dat
The MIG-23ML: http://speedy.sh/6Mzbn/mig23.dat
MIG-23ML’s AFM test: http://speedy.sh/mHuGN/mig23-afm.dat
I’m not too used with file upload servers so far, so if the above aren’t easy to access, try the following:
http://www.fileconvoy.com/dfl.php?id=gf2d3c0e6c6644f66999347860ab5844ad6b9be9c6
Have a good day!:-)
Ok you absolutely need to draw the EM charts for your models, comparing in flights with other models is not the way to go …
I think topolo has a program to draw them , contact him
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I would be very interested in this tool aswell, unless its “doghouse” …i have that already.
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The MIG-23ML: http://speedy.sh/6Mzbn/mig23.dat
MIG-23ML’s AFM test: http://speedy.sh/mHuGN/mig23-afm.datDo not mind if I say a word?
Great work, but there are a number of comments.
MiG-23ML
I just checked the dat files (without using the program).
Cl, CD, Trust far from reality, especially Cd and Trust. EM charts maybe similar in some cases.
there is another point
if the coefficients Cl, Cd are used as-is. Then in OFM (mig23).dat
DRAG COEFFICIENT CD
Table Multiplier should be set to 0.66666
but if used AFM, then Table Multiplier should be set to 0.66666 in mig23.dat and in mig23_afm.dat Table Multiplier should be set to 1
if I’m wrong request to the Mav-jp, correct me -
I missed this thread in the past, just found it……nice someone is interested in Flogger and Fishbed FMs - I flied them often in the past…even tried to respect varioust flight regime limitations - for example there is G load limit for Flogger during sweep change (it was quite attention intensive “voluntary penalization”) or structural speed limit for low flying Fishbed - especially BIS version on second stage AB …there was also time limit I set for myself - 90s (it is 1-3min? in RL) + high limit <4000m for this regime IIRC
This is not easy to constantly check speed, angels, G-load ect when avoiding Amraams, trying to find firing solution with weak radar and almost zero ECCM missile capability…
so it would be really nice to include damage penalizations or even AC destruction in future BMS code…I allways desired to have nice designed PvP scenario, where matured RED pilots (Mig nerds), flying eastern jets are making nice, rich and realistic environment for F-16 nerds :mrgreen:
BTW - F4AF has various 21 dat versions modeled - Mig-21-93 is the only R-25 2nd stage AB capable FM, not 21BIS IMO (of course,there are no MIG stages modeled - the engine is just stronger on AB)…but file format is coded…
…also 21F13 is usually the weakest modeled Fishbed in all Falcon versions - it almost does not fly- but according to real pilots opinion, this very first version is the most comfortable to fly, including the BIS…it has even much better visibility -
@OSD:
Do not mind if I say a word?
Great work, but there are a number of comments.
MiG-23ML
I just checked the dat files (without using the program).
Cl, CD, Trust far from reality, especially Cd and Trust. EM charts maybe similar in some cases.
there is another point
if the coefficients Cl, Cd are used as-is. Then in OFM (mig23).dat
DRAG COEFFICIENT CD
Table Multiplier should be set to 0.66666
but if used AFM, then Table Multiplier should be set to 0.66666 in mig23.dat and in mig23_afm.dat Table Multiplier should be set to 1
if I’m wrong request to the Mav-jp, correct meThis is correct for multiplying coefficient
OFM code multiplies the drag coefficient by 1/0.6666 , don’t ask me why this oddity….
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Hello again,
Thanks for telling me about these aspects…, so as i’ve also noticed, there is a great difference in drag between OFM and AFM and now i have my answer in that multiplier (only for CD). About the lift (CL) values…, i can’t obtain some better ones at the moment, but i’ll keep trying to get them to more correct areas, while the drag values, as far as i know, are a bit higher than they should, though i hope they respect a realistic form as they travel from -90 to +90 AoA and from Mach = 0 to 2.5. About the thrust tables, Mav also gave me a more clear view and as it seems i confused the static thrust with the one at a higher Mach number, so i’ll try to correct that as well.
Have a good day!
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Hello again,
Thanks for telling me about these aspects…, so as i’ve also noticed, there is a great difference in drag between OFM and AFM and now i have my answer in that multiplier (only for CD). About the lift (CL) values…, i can’t obtain some better ones at the moment, but i’ll keep trying to get them to more correct areas, while the drag values, as far as i know, are a bit higher than they should, though i hope they respect a realistic form as they travel from -90 to +90 AoA and from Mach = 0 to 2.5. About the thrust tables, Mav also gave me a more clear view and as it seems i confused the static thrust with the one at a higher Mach number, so i’ll try to correct that as well.
Have a good day!
Again you need to draw EM charts:-)
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wasn’t there mig-21 MF, BIS and Mig-23 MF and ML flight model by Topolo for FF with EM charts already done?
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Hello again,
Thanks for telling me about these aspects…, so as i’ve also noticed, there is a great difference in drag between OFM and AFM and now i have my answer in that multiplier (only for CD). About the lift (CL) values…, i can’t obtain some better ones at the moment, but i’ll keep trying to get them to more correct areas, while the drag values, as far as i know, are a bit higher than they should, though i hope they respect a realistic form as they travel from -90 to +90 AoA and from Mach = 0 to 2.5. About the thrust tables, Mav also gave me a more clear view and as it seems i confused the static thrust with the one at a higher Mach number, so i’ll try to correct that as well.Have a good day!
So it will be easier.
Add a few charts from practical aerodynamics of the MiG-23ML.23_Cl_local_AOA
X-axis = Cl.
Y-axis = local_AOA (units); localAOA= 2 * trueAOA – 5.523_Cl_to_M
X-axis = Cl
Y-axis = Mach number.23_Cdo
X-axis = Cd0 with different sweep of wing.
Y-axis = Mach number.23_Cl_to_Cd
X-axis = Cl
Y-axis = Cd (total)
The top chart for wing sweep = 45 with two R-23
The bottom chart for a clean aircraftwith different swept wing.23_AC
for Mach number = 0.6
X-axis = aerodynamic quality (Cl/Cd)
Y-axis = Cl23_trust
X-axis = Thrust with lossy in the inlet and nozzle (installed trust)
Y-axis = Mach number.
the dotted line – Thrust Full AB
dashed line with a point - military power -
Again you need to draw EM charts:-)
I can provide the original russian EM charts for Su-27, Mig-23ML, Mig-25RB and Mig-29 if that helps.
Text is russian, but the graphs are understandable. -
In the same “classical form” as used in US? I really wish to see their measured parameters. My PM box is open.
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I’d really like to see
@A.S:the original russian EM charts for Su-27
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I up them next free time for you guys. KGB stlye :mrgreen:
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Hello again,
I had those charts too, and i was willing to upload them here right away as a starting reference, but then i saw this last post containing exactly that!:eek:
I’ve used those for a while as a comparison method with my results, because those charts don’t contain all the data ranges we need (ex: CL2AoA for a given Mach number, or CD), data which i couldn’t yet find anywhere, otherwise things would’ve been done easily long before! So, for the moment at least…, i can only provide results that i’ve obtained with a software which uses 3D panel methods to obtain CL2AoA and CD2AoA for a given Mach of 0.1 (to avoid compressibility effects), values which have been later derived for the rest of the Mach numbers through transonic and up to 2.5!
Of course, as these values approach transonic regions which are mostly dominated by the normal shock presence, and beyond, where things get slightly better (in terms of reduced overall drag), where the oblique shocks and Mach cones rule the rest as speed increases…, there will definitely be a divergence in terms of increasing error margins…, yet i hope they won’t be alarmingly great in comparison to some real data, which hopefully the russians have archived at Tsagi.
Here are the charts that i’ve obtained after the last corrections:
Finally, PDF’s worked!
I’m not putting my hand into the fire to tell that these corrected thrust levels are appropriate and close to real, but at least i tweaked them so that the aircraft accelerates accordingly to what the manual says here:
http://backfiretu-22m.tripod.com/id16.html
Thus, even if i covered that area, it’s only a small one, so in all the other regions for which i don’t have this kind of data (longitudinal accelerations within some given conditions), i can only presume how it could be…, and even if i had that kind of data, it would mean tons to read for every condition and so on the time to tweak until i get the proper reactions. From this point of view, i honestly can’t help much more…, i’m only able to provide some better main aerodynamic coefficients (CL and CD to alpha), and replace them over the initial ones. Even if the MIG-23ML wasn’t the easiest choice because of the swing wings which drastically modify these coefficients with every position, i was able to obtain, from my perspective, some overall good and reliable data on the 23’s aero only. I feel sorry if this isn’t good enough, but i’m not able at the moment to provide more.
Thank you for your time,
Maverick! -
Some inflections, at least for the CL values near critical alpha values, are due to the spline function that i’ve applied to them in Excel, just to not have those sharp looking edges…, although the sim itself might also (i don’t know) interpolate values around those abrupt inflections within the data tables when playing!
Please correct me where you might think there is a problem and if you may…, tell me how should it be, otherwise i might actually make mistakes here or there without having a clear view of what could be so wrong. In terms of CD2AoA, i’ve reworked the data and made some significant reductions at lower AoA, and slightly increased them after the first (with wings swept forward at 16 deg.) and complete airflow separation (stall) that occurs around 11…13 deg AoA; after the first partial separation at around 10 deg AoA and second and full separation (stall) at around 22 deg AoA, when having the wings swept to 45, and finally and finally did the same for the wings swept at 72, with the fully developed stall at around 26…27 deg AoA. These critical angles of attack have been estimated according to the wing’s aspect ratio (which of course vary with the sweep angle). At 90 and -90 deg AoA though…, i’m pretty sure the CD values are very close to real now (depending on Mach number also), having any inaccuracy/error lowering as alpha travels from -45 to -90 and between +45 to +90.
The CL values that i’ve initially obtained were 2% to 8% higher than they should, so at least these weren’t too far from reality and now these are also corrected and much better.
I’d also like to share a very useful (more or less depending on everyone’s acknowledgement on aerodynamics alone) site which can give everyone some good clues about aerodynamics and more:
http://www.aerospaceweb.org/question/aerodynamics/q0194.shtml
Have a good day!
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Please correct me where you might think there is a problem and if you may…, tell me how should it be
Cd at Null Lift to low.
This is a major error, the rest of the sequence.Check again the lower chart 23_Cl_to_Cd.
Look for Cd at zero Cl. Cd with zero lift is always greater than 0.02, for any Match number and wing sweep.
can build a chart Cd with zero lift point by point directly from the lower chart on 23_Cl_to_Cd (31 page of aerodynamic MiG-23).
or can be made easier.
just take data from the chart 23_Cdo (page 25). Cd0 is the drag coefficient at zero lift force, but in the case of the MiG-23. Cd0 obtained when the angle of attack is less than 0 AOA (asymmetric profile). -
@A.S:
I can provide the original russian EM charts for Su-27, Mig-23ML, Mig-25RB and Mig-29 if that helps.
Text is russian, but the graphs are understandable.I’d be interested in the Su- charts
Thank you.
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Hello again,
I don’t even know how to start this as I haven’t shared any info in about years because I actually didn’t get the proper time needed anymore, but hopefully I’ve come up with some better aero and thrust data, not just for the MIG-23 ML, but also for 3 other fighters, trusting that these results would be a lot better! ntinue the purpose of gathering/obtaining the aero (also the thrust data, but I’m primarily capable for aero) tables needed to have these birds fly as authentic as they’ve ever been in our simulator.
I want to apologize to OSD and others for not paying too much attention on the lower AoA CD’s which indeed are erratically low…, I’ve done this mistake by confusing those those Cx charts that were written in russian (which I lack) and I mislead myself by interpreting them wrong. I misunderstood those charts, which were probably regarding the CD (Cx) increase due to some added stores or whatever and I can’t believe even now that I’ve let such low CD0 values like 0.002! Not even the aerodynamically shaped water drop can have such a low drag coef. These were the Cx(CD) diagrams/charts that I’ve confused I’m sorry because:
I already felt this was wrong and yet I just manually forced a function between zero lift alpha (AoA) and 15-20 alpha just to make this possible, but I was foul enough not to trust what I already knew:(, also waiting so much until I had this corrected!
The CL is also a bit refined and corrected for subsonic regimes where the function with Mach was inverse and is now corrected. I’ve uploaded 2 versions of the tables, one with CL drop beyond stall AoA (suitable for the AFM) and another version which works for the OFM (the OFM seems to not like CL reduction as the AoA increases) which has an almost constant CL gradient up to about 40…45deg. AOA from where any CL would start to drop. So it won’t simulate a stall for the OFM, but the critical AoA must be somehow limited on the OFM depending on wing sweep (as it’s the case with the variable geometry wings) to the known or calculated critical AoA for each wing position, otherwise we’d witness these aircraft manoeuvre much better than normal which is not the point for a good simulation, that’s why it would be more appropriate to use the correct aero tables on the AFM which accepts CL drops as AoA increases, although for the AFM I don’t know how to make it simulate a wing stall and/or wing rocking at a given AoA.
Now regarding the thrust tables, I have to admit that I’ve used some more empirical functions (that keep increasing thrust as the dynamic pressure and IAS increases) for altitudes >10000 feet which neglect the possible supersonic airflow (mach/shock waves ingestion) that may occur within the air intake of the engine, which in reality would lead to hazardous vibrations which could damage the engine, yet by thinking that the design of these intakes with the dimensions and positions of the splitter plate (boundary layer separator) should not allow such problems occur up to about 2.1 Mach (at least for the F-16), I would neglect the appearance of such situations even for an addition of further 0.4 Mach, thus continuing with the same functions to Mach 2.5 where our tables stop, presuming that between 2.1 and 2.5 there won’t be great changes in the airflow at the engine’s intake! Below 10000 I it would’ve been exaggerated to let the thrust continue to rise with Mach, so I manually tweaked it there (making the thrust slope become negative) to have it more appropriate.
Everywhere I’ve modified some default values/data, I have written “#MODIFIED” in order to tell what has been touched!
With the giving CL’s and critical AoAs (I’ve determined the stall/critical AoAs with some empirical equations with acceptable error) of the MIG-23 ML to say the least, the turn rates achieved are in a nearly perfect match with the real life ML’s manual, so at the moment there isn’t much that there can be done to increase the accuracy of the CL tables for the aircraft that I’ve worked on so far! At least these are the most correct values that I could obtain for the CL in particular! The CD tables might be reworked as needed, as well as the thrust tables, cause these give me a harder time in order to get them better and I can’t be sure of how accurate they are, but even so, from my opinion they should already provide more than 85-95% accuracy, which should be better than the default/actual tables.
You will notice that the CD for AoA +/-90 is 1.15 as arbitrary for Mach=0 and all aircraft start from this value as a general CD for those angles and from those angles of attack, the CD develops accordingly throughout the rest of the AoA range as they are calculated individually for each aircraft. We should know that a flat plate would produce a CD of about 2 at 90 degrees AoA having an infinite wingspan (so that’s only the case of a 2D airflow), yet for a real 3D 1 meter square flat plate (is a rugged example but not too wrong compared to any aircraft in such a situation) the CD would not get any higher than 1.2 at 90 alpha, while the best parachutes only manage to reach 1.55 or so…! According to size and wake flow generated behind the aircraft that would either fall vertically or reach a +/-90 deg. AoA, the most appropriate value would be around 1.15…1.2, which I used. The CD is expected to vary according to AoA/CL and Mach number. The hardest thing is finding the correct slopes/derivatives for each case, which is also a hard time for any CFD anyway, but hopefully I’ll be able to correct them with small but fair steps when I get the time.
I’ve attached the files for all 4 aircraft (F-4E, F-14’s, MIG-23ML and MIG-21) with their respective OFM/AFM model and the aero/thrust charts for MIG-23ML and F-4E which I managed to work on so far:
Here are the tables:
Here are the charts:
OSD, when you have the time, please check these values again! Thank you!
A great day to all the community!:)