some aim54c loft test
all M1.2 9000m 75km launch vs M1.2 9000m
1.in game, 17.5° loft
2.old game (from 2.17) , 7.5° loft
3.tested 35° loft
4.derby loft
the missile dive too late, and miss target due to strange LOFT code
4 Likes
Very interesting, thanks for testing these out! So looks like a ~36% increase in impact velocity with your 35° loft vs the games 17.5° loft with those specific launch parameters and range to target
Random bit of curiosity, could you test the same M1.2 9km launch but do a 10° manual loft along with the 35° loft code you made, and maybe a 45° loft test too? I’m curious about how a 45° loft might effect it, and how much a manual loft might change the results as well.
Sorry for asking you to test all these things, and thanks for performing all these tests, I don’t know how to do it myself. I wish I knew how, there’s so many things I wanna test lmao.
seems that compared to 35° LOFT, 45° LOFT does not provide more kinetic energy gains, and the flight time is also longer.
1 Like
Good to know, thanks!
It’d be interesting to see how the AIM-54C with 35° improved loft profile and the AIM-54C with the current in-game loft profile fares against the other ARH missiles when compared to this chart you posted as well:
With the 35° improved loft profile it has considerably more energy at impact than the rest of the missiles seen here from the looks of it, but with the current in-game loft, I’d guess they’re likely similar.
3 Likes
I think that will be more significant when launched at sea level, and it will be affected by loftTargetElevation and loftTargetOmegaMax. If max altitude reached by loft in 35 and 45 degrees are similar, then 45 degrees loft won’t benefit from less drag from the higher altitude.
I think the max loft altitude is determined by loftTargeElevation and loftTargetOmegaMax, the loftElevation only affects how aggressive it is on reaching the desired altitude.
With -15 degrees as loftTargetElevation, assuming missile is trying to keep target -15 degrees below horizon, this will yield a max loft altitude delta of ~19km, which remain unchanged for both 35 degree and 45 degree launch that were conducted. This explains why kinematics remain mostly unchanged when loft angle is increased.
My hypothesis is, to get more kinematics out of 45 degree loft, loftTargetElevation need to be -18 degrees or a bit higher, which yield a max loft altitude delta of 23km. The missile will try to climb to 23,000+9,000 (target altitude) = 32,000m when launched against a target at 9000m altitude, instead of previous 28000m.
loftTargetElevation=-20 should yield ~25km altitude delta, which means missile will try to climb to 34000m when launched against a 9km target.
3 Likes
Something else im interested in is the implementation of energy management code like every radar missiles after the AIM-7F except the AIM-54’s got.
Code:
Energy management code from the AIM-120:
Missing energy management code for the AIM-54:
I mentioned this a few times, but I think the AIM-54’s are flying much less optimized flight paths due to them having access to 100% of their fin deflection regardless of time to target. This likely leads to much less “smooth” trajectories, which wastes energy.
Another thing is energy management code likely limits how much the missile will try to adjust to every small flight trajectory change of the target.
2 Likes
Yes, more aggressive pull up maneuver can reduces time spent in lower altitude, thus reduces energy loss due to drag.
Manual lofting on Phoenix is very useful because of what you mentioned.
Where as Phoenix was supposed to be very aggressive at climbing even when launched horizontally, as seen from IRL footage.
Also, sorry, I read your post wrong. For the first part, yes having 100% fin deflection during entire flight will waste more energy since minor avoidance maneuver of target will cause Phoenix pull hard to compensate.
2 Likes
And don’t forget the missing thrust which was reduced on the first “fix” aswell
Missing 24% of the current thrust
6 Likes
Oh yikes, that’s a lot of missing thrust wtf. What document is that excerpt from if you don’t mind me asking? Looks like its about the AIM-54A considering the warhead?
Also, seeing as gaijin typically models higher thrust to model drag reduction during motor burn, isnt the missile missing an excessive amount of thrust?
4 Likes
Ada142508 1984 weapons file
3 Likes
Idk why i havent been sniffing around the DTIC website for new AIM-54 info, look of potential goodies in there.
AIM-54A has home-on-jam and, contrary to what some devs and what gaijin has stated publicly and believe, is an effective missile against small maneuvering targets:
Spoiler
5 Likes
If I had to guess, 4000 lbs is likely the peak thrust and not average thrust. A constant 4000 lbs thrust for 30 seconds with 170kg of propellant would suggest a specific impulse of over 330 seconds, which is not realistic for a solid propellant motor.
Thrust is more or less accurate in-game. The weapons file is not a good source as there are other sources (even primary ones) stating lower thrust figures. It is possible that the thrust reaches 4,000 lb-f… but the overall output deltaV would be too high if this was for 30 full seconds at that thrust rating. The rating is allegedly around 99,000 to 100,000 lb-s with 25-30 second burn time. This would indicate an average thrust rating of 4,000 pounds for 25 seconds or 3,300 pounds for 30 seconds depending on conditions.
Was not realistic at the time, but is possible today with some very experimental propellants. Nonetheless, the figure is wrong. Outsider’s view states the AIM-54 to have approximately 97,000 lb-s total impulse. This is not possible with 30 seconds burn time and 4,000 lbf thrust.
Thrust model in game is simplistic where it assumes thrust is constant for entire duration of burn. The thrust of solid rocket motor depends on the shape of propellant and their composition, this changes over time.
It is entirely possible to craft a single stage solid rocket motor that match all of these figures in its thrust curve, by adjusting propellant shape.
For example, a star shaped hollow cone, with 10 or more pointy arms, in propellant will yield higher thrust during first few seconds of burn, then reduces to a stable level of thrust.
Also, solid rocket motor don’t just turn off at the end of burn, there is always some propellant residuals that takes rocket motor few seconds before its thrust drop to zero. Base drag reduction still exists during this time period and missile enjoy few more seconds of reduced drag after burn ends.
Sadly these info probably never will be released to the public.
So quoting total impulse is more reliable than thrusts X over Y seconds.
2 Likes
He said 4000lb may be peak thrust.
If Aim54 starts the burn at 4000lb force, then reduces and reaches 2500lb at end of the burn, then the total impulse will be around 97,500lb-s = 30x2500 + 30x1500/2.
This also means the average thrust is 3250lb, which translates to 14456N of force, very close to in-game value.
On the other hand, the higher thrust at the beginning of the burn will significantly improve missile’s kinematics; since the reduced thrust at the later portion of the flight acts as a “sustainer”.
It is possible the “too much drag” issue mentioned earlier in the post wasn’t due to missile having too much drag, perhaps it was rocket motor in game uses average thrust as constant thrust, where IRL it had much higher thrust at the beginning of the burn.
2 Likes
Such as?
1 Like
I read it twice, it said nothing about small manuevering targets. Only made the distinction that it has had successful targeting against small targets as well as manuevering targets. It didn’t combine both.
Yes my bad, my point was that gaijins statements about the AIM-54 being ineffective against anything but high altitude strategic bombers is patently false, this is just another document to support that.
3 Likes