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Problem: The AI controlled MiG-15bis has unrealistic performance. Cause: Some of the aerodynamic characteristics of the SFM exceed those of the real aircraft. If we compare the SFM data in MiG-15bis.lua to the aerodynamic data from the real technical manual for the MiG-15bis. https://www.digitalcombatsimulator.com/en/files/2365583/ Some discrepancies are apparent. For example, the DCS MIG-15Bis SFM has 200 kgf more thrust than the real MiG-15 bis at low speed. This is because the thrust values for the SFM are based on bench tests of the VK-1 Engine and not on installed thrust data. The installation losses are given in Figure 84. The manual confirms this and notes figure 80, reflects these losses. Since thrust available defines many of the performance parameters of the aircraft. It is important that the SFM thrust parameters match this data. Using the data from the technical manual, I’ve updated almost all of the SFM of the MIG-15bis to more closely match the real aircraft. Feel free to try it out, I’ve placed a link below. The mod contains extensive notes. I cite a source for almost every change I’ve made to the SFM too. Link to Mod: https://drive.google.com/drive/folders/19cQXcBNfOdnoJkxlY2BFdUO3Zc77KESm?usp=sharing I’ve tested and validated the performance of this mod in a few different ways too. The max velocity at various altitudes, climb rates as given in table 5 of the technical manual. The SFM also matches the level acceleration data in figures 46. Below I’ll discuss some of the changes I’ve made to the SFM to more closely match the historical data below. Almost all of the aerodynamic table was changed to better match the source data. Drag: The drag polars Cx = Cx_0 + Cy^2*B2 +Cy^4*B4 Were changed to better match figures 55 and 54. A new data point was also added at mach 0.86. Which is important because the lift and drag become nonlinear here due to mach effects. LIFT: Cy max as function of Mach was changed to match Figure 185. The current values in SFM are too high, resulting in too much lift. The SFM Cy max values are drawn below in red, The mod’s Cy max are drawn in the green line. Cy Alpha was also changed to more closely match the actual aircraft. Cy0, the zero AOA lift coefficient, was set to match the lift polar in figure 51. Aldop was set to the AOA corresponding to CY max from fig 185 and Cy alpha at that mach. AOA = ((1/Cya)*Cy+((Cy0*-1)/Cya)) Engine: Some additional changes were also made to the SFM engine model. Dpdh_m was changed to more closely match the loss of thrust as a function of altitude. Thrust Kgf At Alt = Thrust Base (Kgf)-(dpdh*(Alt m*0.001) Above, the thrust available at 5000 meters for SFM is drawn in red. The mods values are drawn in blue. At low speeds the mod more closely matches real aircraft. The mod also changes to the idle rpm and thrust specific fuel to more closely data in table 19. Roll Rate: Omxmax, the max roll rate was changed to match Figure 40: Other Changes and Notes: V_opt = 367 / 3.6, -- velocity for L/D Max, Mach .3 at 0 m =367 TAS Kph Page 24 . Setting V_opt to high means the AI does not have enough excess thrust to maneuver. causing it to only do high speed loops. V_cruise = 1.31*V_opt .Def of Vopt from translation of Russian Aircraft Design book. https://archive.org/details/DTIC_AD0741485/page/62/mode/1up g_suit = 0.0, -- This Aircraft does not have a G suit, Default is 0.35, AI will sustain 6g turns all F-86 = 0.7 -- Performance Limiting Factors of AI SFM are AI Level, Cy Max, drag, Aldop, and g_suit, Vopt CAS_min = 50, -- This is Close Air Support time on station in Minutes. How long (the AI) will LOITER TIME, WEAPON CHANGES There are also some changes to the weapons parameters. I plan on doing a separate post on these changes. One of the most impactful of these changes was changing the value Tbl.effective_fire_distance to 600m to reflect the data on the 23mm and 37mm cannon uses as presented in Table 18 in The Flying Techniques and Combat Use of the MiG-17 Which gives the effective ranges when firing at fighter aircraft as 180 to 550 Meters. The previous value was 1km and resulted in a sniper bot. There are also changes to dispersion values, shell and fillers weights. These changes were made to match the data from Soviet Manual on Aircraft projectiles. https://disk.yandex.com/i/YVj0XI6O3Mu4LM That just about covers all the changes I’ve made to the MIG-15bis SFM. While these changes are not a miracle fix for the AI or the SFM. I feel the do represent a significant improvement to the AI MIG-15bis making the AI MiG-15 a much more realistic and engaging opponent. I believe this project illustrates that significant improvement to the AI performance can be made if one takes the time to realistically tune the SFM parameters. With a spreadsheet and an understanding of the SFM parameters it’s possible to create much more realistic SFM AI opponents. Eagle Dynamic could also do a lot to improve the situation by better explaining the SFM parameters. Many of the notes in various SFM files date back over a decade and are from unofficial sources, some are misleading others are simply incorrect. If you read this far, thanks for taking the time to do so. If anyone wants it, I will share the google sheet I used to help develop this MOD. Be forewarned though, it’s a hot mess and some of the units are in …Gasp! American units of insanity. I attached a track of a big dog fight mission, sabres V Mig15's down low. I know it's need for the report. Thanks for taking them time. MIG 15 Big Gun Fight.trk