Missile aerodynamics project
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In this case pls. explain how can it be that you do not get negative weight in game when set bigger prop weight than empty weight…? As I can remember I tired that I set 0 for weight of missile and somehow the code works. Also strange that if I treat as sum the two weight I got better results. I do not understand the situation.
exactly for the reason i was telling you
weight = inputData->wm0 + wprop;
inputData->wm0 is the weight you put in the data file, so here the EMPTY weight should be placed
after that the weight is an ADDITION of empty and prop weight
SO you can never have a negative value…
your argument is the exact demonstration that the code works indeed with empty value while your reasoning would be correct IF the code was Weigth = total weight - prop ….see ?
as far as better results are concerned, the reason is simple, you are all working with wrong code asumptions, so basically all your conclusions might be wrong as well
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so if i summarize correctly
the code working OK
The DATA are wrong, empty weight should be place in data file whereas since 1997 total Weight have be placed
So in short, the best thing to do is to put empty weight, then readjust impulse in order to match the same top speed.
After that of course, the weight beeing reajusted correctly lighter, the flight caracteristic are better, so to match again SPx behavior, CX/CZ should be changed accordingly
so this is not easy game to change initial weight and change everything else to match same behavior, this is why we didnt change them…
now if you want to redo all missiles, feel free but start from correct code
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Good point, but isnt there a way to automatize this ? Compute correct database inputs once, then change them ?
The formula you briefly described are not that hard to compute. Especially since lift and drag forces are independent from atmosphere state…
Edit : incorrect, please disregard.
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after that the weight is an ADDITION of empty and prop weight
+The DATA are wrong, empty weight should be place in data file whereas since 1997 total Weight have be placed
Just for clarification.
375 # Weight of Missile (lbs) ––>this is the burnout weight
135 # Weight of propellant (lbs) ----> weight of rocket fuelThe addition of these values are the total weight. If this is statement is right means what I have discovered about 3 years ago. All missiles have wrong values in current dat files but I correted the weight in my mod as I explanied above.
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Just for clarification.
375 # Weight of Missile (lbs) ––>this is the burnout weight
135 # Weight of propellant (lbs) ----> weight of rocket fuelThe addition of these values are the total weight. If this is statement is right means what I have discovered about 3 years ago. All missiles have wrong values in current dat files but I correted the weight in my mod as I explanied above.
and i think you did not read my first post entirely.
yes we know all DAT files were wrong in this aspect, but as original devs and SPx devs have set up their models taking into account this bug if you want to get same results than SPX data while fixing the bug, you need to REDO all VALUES of ALL MISSILES
keeping the same impulses and CX / CZ but fixing only the weight bug is leading to a missile FM that will not match what original devs were seeking…
NOW, if the assumption is that the original devs , or SPx devs were not aware of this bug AND have done their FM by CALCULATING them outside the F4 code and not by TEST/TRIAL in game, that means you mod is correct, if not your mod is incorrect.
clear now ?
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Good point, but isnt there a way to automatize this ? Compute correct database inputs once, then change them ?
The formula you briefly described are not that hard to compute. Especially since lift and drag forces are independent from atmosphere state … :oops:
INCORRECT statement.
lift and drag are dependant from atmosphere because density , pressure , dynamic pressure and speed of sound is compute each frame taking into account atmosphere and Altitude
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Ah, I read somewhere else missiles performance was unrealistic because didnt depend on altitude, drag and lift being only dependent upon the speed of the missile. But if in missile data, there is a table of drag/lift COEFFICIENT per AOA, then it is multiplied by speed squared and density (together, dynamic pressure), then I withdraw my previous statement.
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and i think you did not read my first post entirely.
I did it.
keeping the same impulses and CX / CZ but fixing only the weight bug is leading to a missile FM that will not match what original devs were seeking…
Of course, I know. Did you read my aspect and estimation process…?
I did slighly or no changes on red SAM aero data. I just set the thurst, impluse and weight data well and voile, the speed-thrust char. was 5-10% within the RL test launches.
SA-2 without Cx/Cz change.
https://www.benchmarksims.org/forum/showthread.php?8230-Suggestion-for-database-data-supply&p=107477&viewfull=1#post107477SA-2 with Cx/Cz change.
https://www.benchmarksims.org/forum/showthread.php?8230-Suggestion-for-database-data-supply&p=114975&viewfull=1#post114975Of coruse this method - by altering the Cx/Cz only by experimental way - is anything but not scientific but the result is generally us qiite close to RL. I rather accept this result than waiting forever for 100% scientific method with 5-6% more percent accuracy. This is not a military grade simulatior to train RL pilots. The method why I used provide lightyears better kinematics modeling than current considering only the range and speed-time (distance) charateristics. Modeling the available lift for turns according to RL limits requires calculations because in Falcon guidance values and targets simply do not make possible the testing.
Guidance valus also have issues because in RL even the stone age Russian SAMs had multiple guidance mode with different leading…
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Ah, I read somewhere else missiles performance was unrealistic because didnt depend on altitude, drag and lift being only dependent upon the speed of the missile. But if in missile data, there is a table of drag/lift COEFFICIENT per AOA, then it is multiplied by speed squared and density (together, dynamic pressure), then I withdraw my previous statement.
This likely concerned on DCS. Falcon 4.0 since the beginning has areo modeling - as I know, because the basic structire of the game is still close to original - while DCS/LOMAC had scripted behavior until recent times.
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Of coruse this method - by altering the Cx/Cz only by experimental way - is anything but not scientific but the result is generally us qiite close to RL. I rather accept this result than waiting forever for 100% scientific method with 5-6% more percent accuracy. This is not a military grade simulatior to train RL pilots. The method why I used provide lightyears better kinematics modeling than current considering only the range and speed-time (distance) charateristics. Modeling the available lift for turns according to RL limits requires calculations because in Falcon guidance values and targets simply do not make possible the testing.
Guidance valus also have issues because in RL even the stone age Russian SAMs had multiple guidance mode with different leading…
I get your point, man, but dont be stubborn either. Your experiments are really useful but programming is not physics, the code works in a theoretical way which can be fully understood provided you have programming knowledge and some time. This theoretical way can be wrong (ie : not modelizing sth properly), that’s a bug ; but the source code IS how BMS works, period.
In physics, experiments are always right, and theory try to modelize it.
In a sim, the code is always right, experiments are useful to try to understand how the code works if you dont know how (or not perfectly), and to detect bugs. For bugs, you then check the code for its origin.Just my 2 cents….
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Fix all the dat files by adjusting the weigths to the correct empty weight, which would require a complete rewritten of the other values of the dat file in order to match again the correct intended behavior
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Adjust the code , to read weight as total weight, but then that would require to keep same weight in the dat file but to change all the other values of dat fil to match again the correct intended behavior (this is VERY HACKISH)
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Dont touch anything and keep the correct intended behavior.
IMO, Do not go option n°2 …. As you well know, coder has already a lot of work vs time available …
This is a work for datamen… I think it is time to go on option 1 … Together.
I kept an eye on Monli’s thread and by comparing results to my documents (unable to share them as they are confidential) I have good faith on Monli’s analysis. Sure… Not always 1000% exact (who can give a 100% truth model in a simulator … Nobody), but by look at he said about missile energy, flight profil, global perfo and trajectory diagrams … My conclusion is that his work on the .dat makes them close to RL than the one we had before… I deeeeeply consider and respect and admir RP team work, it dosen’t mean it can’t be improved… Especially using the materials that Molni has on Soviet systems.
Time to go forward together … But step by step and progressively. No need to hurry and no need to do everthing in one shot.
Actually, we are already in touch. And some of BMS missile.dat already fit with code requirement about missile weight and aero data… At least … Experimental results in-game fit (quite good) with RL diagrams as Molni showed.Step by step …
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I think i will create a working group on this . I am waiting for someone to give me an answer for a tool we need…plus another tool.that falcas has to make
Keep tuned guys i will recruit soon
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hey molni,
can you point me in the direction of your missile database? i’m somewhat impatient! :uham:
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I think i will create a working group on this . I am waiting for someone to give me an answer for a tool we need…plus another tool.that falcas has to make
Keep tuned guys i will recruit soon
If you need any automation tools let me know, I can write one for this purpose quite quickly going by the requirements…
That is, if you don’t already have something.
Would just need to let me know what type of operations you need, on what data set.
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hey molni,
can you point me in the direction of your missile database? i’m somewhat impatient! :uham:
http://www.mediafire.com/download/p2chwrif72eccnn/Misdata.zip
To get the same SAM behavior what my MOD has a lot mor is required than only missile dat files.
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you have made an impatient person very happy!
what more is needed? do you think i can use the Generic Mod Enabler jag mentioned to accomplish this? i am looking for something non-permanent so i can easily switch to MP standard.
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Radar dat files are also changed and range for missile in database and launcher and battalion modeling values should be recalculated with F4B.
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how important are the modeling values? that sounds kind of important. something i probably shouldn’t be messing with.
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Whithout changing the range in DB the SAMs simply do not launch from higher distance the missiles and from my aspect the old SAMs in radar modeling values was not enogh good I also changed values for radars. Range, chaff sensitivy, beam modifiers, etc.
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that sounds like something i can leave alone. i am more concerned with realistic flight models than AI behavior. much thanks!
and Jags. thanks for the GME hint. i am now going to try out all sorts of things i was afraid to do. keep working!