Spoiler
Regarding your statements about my “napkin math” and the AIM-120’s thrust profile, the sustainer is essential to reach higher speeds and then maintain them for whatever time it can. At lower altitudes the booster will not be reaching mach 4 as the R-77s can. This is reflected in the relevant charts.
So no, this doesn’t contradict my earlier “assumptions”. The boost-sustain profile does allow for you to sustain the speeds of the initial boost, but at a certain point drag is much reduced and the sustainer can actually allow for higher top speeds. For the AIM-120 it seems that the top speed of mach 4 is only achievable in the same manner as the R-27ER’s top speed is only achievable. (At very high altitude and initial launch speeds). The R-77 is still the winner here, having a similar thrust profile to the AIM-120C-5 and lower drag grid fins for such high supersonic speeds.
Yes, you’re correct the R-77 is more similar to the AIM-7M in size but with much reduced electronics size, different warhead, tail guidance section instead of wings. It has more modern higher ISP propellant and a better burn profile. Now let me remind you that the AIM-7M has 100km range.
The R-77 is far from the second coming of Jesus, I think that could be quite an offensive statement to some… The R-77 is not better at lower altitudes where the aircraft would be unable to launch above mach 1.3 because wave drag could significantly impact the performance of the missile immediately. This is evident by the fact that it has some 33% less range than R-27ER at 1km altitude seemingly. The AIM-120A wouldn’t be any better, but as altitude increases the R-77’s advantages stack on.
You’ve read my assessments wrong, I think the AIM-120A in a 1v1 BVR situation would not be the breadwinner for engaging an aircraft equipped with the R-27ER. The R-27ER can out-range the AIM-120A and still give the launcher time to evade the AMRAAM. That is all. The fact that you can go full cold and turn around to launch another AMRAAM as the target gets closer kind of nullifies the advantages of the R-27ER. I think it’s a fair match-up and we should see the AIM-120A soon. In fact, I’d advocate for letting the AIM-120A come to the game and give Russia no fox-3 at all until a few updates (6-9 months) later.
Yes the export company overclaims the range of their missile. In no real world situation will it ever hit any target at 75km. No modern airforce is that idiotic that they’d allow such a thing to happen. The missile would be wasted with little to no remaining energy. Unlike the R-77 which seemingly has plenty of energy at the altitudes where it can hit 100km but fails to due to battery life.
They abandoned the R-27ER. It’s still used in training, but when you have massive stocks of things you tend to continue using them as necessary. There was a Harrier equipped with an AIM-120A/B in 2022. I seriously doubt them engaging anything in Syria requires the advantages of the R-77. Using the cheaper old missile stock would be wise.
Lattice fins are well studied, what I’ve claimed is true. The fact that they’d moved to conventional tailfins likely suggests that the missile wants better drag near the end of a lofting trajectory and supports the theory that earlier R-77s did not loft, whereas the newer models likely use such trajectory shaping. For a missile that looks at almost doubling the range of the original R-77 and in a similar sized package… this would be more ideal to move to conventional fins. Grid-fins would be better suited for what I’d call the “brute force missile” designs of Soviet era Russia such as the R-27ER or early R-77.
Also,
If they were to think the legacy style tailfins were better than the grid-fins they’d likely also replace the export models grid fins but they didn’t. They didn’t replace the grid-fins on the ramjet proposal model either.
You could have asked for the book but you didn’t. Instead you just used the fact that I failed to properly cite it as ammo to attack me for whatever reason because… behold… my napkin math was right. The R-77 is a 100km range missile by all means.
TL;DR
The R-77 is a 100km range missile, bar the export RVV-AE which we still do not have solid data to go off of imo. The grid fins are advantageous for a missile that lacks a lofting trajectory and no public knowledge really suggests it has any kind of loft. It looks like Russia was looking more for time to target than peak range. The new R-77M has traditional fins as it is a similar sized missile looking to reach nearly double the range of the original R-77. This requires lofting, and the older style fins do not suffer wave drag between 0.8 and 1.3 mach. At final approach at such ranges the missile can be expected to drop to those speeds and they don’t want it falling out of the air.
