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.
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.
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?
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:
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.
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.
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.
This isn’t entirely true, they have modeled the booster and sustainer. There is no dynamic thrust plot, as you said… but we know the AIM-54 to be a long sustainer-only type burn at a constant thrust.
The document referenced states 4,000 pounds for 30 seconds. We know thanks to primary documentation that it does not have a boost-sustain type motor, rather that it burns for a constant thrust over a long period of time. The in-game thrust is approximately a total of ~96,780s impulse. This is slightly short of the 97,000s quoted in the currently known materials… but it is not 25% off as claimed.
One could make the assertion that to properly model the drag, the thrust would need to be increased maybe 10-15% above normal levels to simulate the reduced drag during motor burn time though. This, and the drag is already too high as it cannot reach its’ top speeds by altitude of around mach 6.
The Aim-54 has and ACM (air combat maneuver) active mode the pilot himself can switch to for close range dogfight situations. The Aim54 was utilized this way on several occasions during the Iran/Iraq war. The Aim54 has proven record of killing small fighter sized targets. There is YouTube videos of radar intercept officers specifically speaking on the ACM active mode.
Whoever typed the description for the devblog is intentionally misleading the Aim-54 capability and unfortunately its evident they may intend to keep it in that state. Hope not.
