Why does the AIM-120D-1 (for simplicity and to not confuse with D-3) have 185 km range, but still uses the exact same burn time of ~7 seconds as the AIM-120C-5, effectively giving it worse performance over the AIM-120C-5 due to the added weight? Isn’t it supposed to be better than the C-5?
Look, I’m no rocket scientist, but I do work with numbers all day and the OCD queen in me is not understanding this at all: How do you get over 50% increase (~54%) in maximum range/performance with a heavier missile weight?
I would like to think that that is, to use a technical term, physically impossible.
Lastly: there are claims it uses, and I’m not joking here, “special fuel grain” to burn hotter. I won’t dismiss this because this is entirely possible. However, the problem comes from the fact that if it indeed did and wasn’t just some rumour passed around, then why isn’t it de facto proven by official sources by now even if with vague language as other products of theirs have? This should be the least believable reason and the more common sense reason is to assume that there was simply more fuel added for the existing rocket motor to justify any weight increase.
I can see 3 possible avenues (as also discussed in this bug report:
Increase rocket burn time to ~9.11 (mathematically the most “this makes complete sense” figure).
Increase thrust produced within the same burn time (the “compromise”; also explains the “denser propellant” theory)
Increase both power and burn time in a 50/50 fashion.
Either way, this 9 kg discrepancy has to show up in a tangible way for people to actually see a difference between the AIM-120C-5 and AIM-120D-1.
So the AIM-120s from the very beginning had a kinetic range of 250km and the only range limitation was battery. The conditions being two planes having a range of Mach 2.5 heading towards each other.
Maximum range increased happened for AIM-120C-5 through the use of new booster motor and increased battery time. But since then the Americans have stated that they increased battery time significantly for aim-120D series allowing for the software to not limit the range of the AIM-120 series anymore. It is also the case that in test shots, aircrafts are extending the range of the AMRAAM by flying higher and faster before release.
“The propulsion and aerodynamic properties off the missile … in that F3R variant … always had the capability to go further. We just had not been able to take advantage of it. So at this point, it’s the way we’re flying it. It’s flying higher and longer. We can fly at a much faster speed at release, which just improves the performance of the missile.” A company spokesperson said this is called “fly-out optimization.”
The “Software and Battery” argument explains how the missile stays “alive” longer, but it doesn’t explain the physical mass increase.
If the AIM-120D is 9 kg heavier than the C-5, but uses the same 7.75s motor, it has a lower thrust-to-weight ratio. Software cannot fix a lack of kinetic energy. In War Thunder, a heavier airframe with the same thrust will always perform worse kinematically. Currently, the game is modeling the AIM-120D as a C-5 carrying 9 kg of lead ballast.
For a direct comparison: look at the R-77-1. It is 15 kg heavier than the base R-77, and Gaijin correctly modeled that mass as additional propellant (and the overall missile weighing more) to reach (or explain) its 110 km maximum range. To be consistent, the 9 kg mass increase on the AIM-120D must also be modeled as propellant (longer burn or higher thrust) to reach/explain its 185 km maximum range. You cannot have a 54% range increase while adding “dead weight” to the same motor.
AIM-120D in Dev now was similar like a C-5, Its worst and easy to notch even hold TWS to datalink then C-5. The lates AIM-120D or even C-5 model should have a better seeker then the B model, but now its completly useless and uncorrect porformance that its should get. No HOB no 40G and worst seeker then A and B model. If F-22 come in near future that would make it useless if AMRAAM didnt get a correct or better performance then now.
We still have AIM-260 which should enter service in 2026-2027. It is speculated to have TVC, dual pulse motor, speed around Mach 5 and two seekers. It does sound good if it will have all these thing but again that is fully speculated and not actually confirmed
This is prob the most nonsensical thing iv read in a while missile ranges are never set based on 2 targets flying at mc 2.5 towards each other considering the test drones are subsonic. and the article you posted is also talking about a shot made with the D-3 anyway not the base D nor dose it also say that software are the only changes nor is it an official source anyways so it wouldn’t even matter.
yes and no
the flight envelope from the manual for an F4e with slats just extends to ~2.05
however, in testing, corrected to standard day conditions it achieved faster
and including temperature correction factor, it could achieve even higher
with both the engines and air frame rated for up to 2.4 for transient operations,
with the transient limit being 5 minutes, which is more than enough for missile testing
the official mach 2 limit is likely a result of this steady state limit, with the QF-4 being able to go past that
however, it is known that the longest publicly acknowledged AMRAAM tests have been conducted on subsonic targets
That is correct, but no one said exactly that the AIM-120D’s 185km range is still the kinetic range when that is still limited by battery time. You can still get a range increase from a missile that is performing worse kinematically compared to its predecessor if you add battery time to it when the missiles as a whole are battery limited and not kinematic limited.
In the case of R-77 and R-77-1, there are explanations to how they were modeled and I explained it in another thread. It is impossible in the case of R-77-1 to model its increase in range over the R-77 without the increase in kinematics, that is not the case here for the AIM-120D. In fact, sources imply the AIM-120D base model did not have a kinematic improvement over the AIM-120C-5 .
literally impossible to hit that range with the current missile even with the increased battery time and an ideal shot at altitude vs an non notching target flying right at you at 1200kph
