The R-77 'ADDER' - History, Design, Performance & Discussion

Machinery of War Discussion Aircraft
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85

Sure, but its still not looking good for the 100km+ theory thats been argued about a ton.

Theres also aerodynamic consideration to be had.

At short ranges and midling speeds, particularly those seen in WT 9/10 times, i think TTT is a toss up, seeing as the bad transonic drag characteristics of the R-77 will hamper it greatly.

At medium ranges, itll likely have a better TTK, its advantage will still be in the improved seeker though, and the range/TTK will likely suffer from the short motor burn if the target maneuvers.

At long range, I doubt the TTK will be particularly different tho there the F&F portion of the missile will be its biggest advantage. The R-77 will likely exceed the AIM-7F in batter life but qurstionnable if it would in range.

The more we learn about the R-77, the less it seems to actually match the all seeing god slaying perfect ARH from 1994 its been sold as before, and more like, yanno, a proper competitor to the early AMRAAM…

Much better seeker than the SARH’s we have, marginally better kinematic range, most likely more from trajectory shaping and slight structural differences than from magic stalinium infuzed rocket motors, better maneuvrability.

86

I dont think its that far fetched the R-27 employment manual gives a max range of 90km and thats just for the regular R-27R, though this is at a very high speed at a very high altitude with a target in similar conditions, but I dont think it would be hard to believe the R-77 can go a similar distance especially since it has a much better impulse to weight ratio and is arguably more aerodynamic in those conditions

Also the AIM-7 sparrows max range of 45km is a seeker limitation not an aerodynamic limitation its aerodynamic range is recorded as being 98km.

I dont think the R-77 is “the all seeing god” but more like an AIM-120A/B/early C with slightly better stats all around (40g vs 35g, slightly more range, etc) Sorta like the early PL-12s. But I wont get much into opinionated performance comparisons

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87

Using the information from Gaijins source that was used for R-27R/ER and the calculated thrust you gave I’m going to make an R-77 missile file with no lofting and an active radar. It will have the same drag coefficient as the AIM-7F which I think is fair. If you disagree please recommend some changes and we’ll see how it does. I’m going to set the guidance time to 120s, it seems that is the limit for R-77-1 and R-77 is likely lower but I’m looking to see what the maximum kinematic range is. If the AIM-7F+ can do 98km, I’m certain the R-77 is capable of that as well.

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88

I set up a mission with 80km starting distance, targets co-alt at 15,000m and closing at ~1.15 mach towards each other. The R-77 custom missile file I made reflects the same statistics shown below and I copied the AIM-7F drag coefficient since they are both 200mm missiles. This also gives a more impartial result since R-77 would realistically have a lower coefficient thanks to the grid fins when flying at speeds above mach 2. (Which it averaged for most of the flight).

Spoiler

Mass - 177kg
End of burn mass - 118kg
Caliber - 200mm
Length - 3.6m
Thrust - 30473.284 Newtons (30828 lb-f converted to newtons, divided by burn time of 4.5s)
Burn time - 4.5s
Drag CxK - 2.3 (same as AIM-7F)

The result was ~80s time to target at a ~75km launch (47 miles).

At higher launch speeds or against much faster targets and higher altitudes, this missile can 100% hit things beyond 100km provided the guidance time is sufficient… Or, perhaps the public data is wrong.

Excuse the AIM-120 model, I don’t have one for the R-77 (yet).

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89

IRL is likely a battery limitation not aerodynamic notice how the range graphs have a wall at the end
image
this is due to the missile running out of battery not energy, if you’ve seen R-24R range graphs the battery wall should be familiar

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90

Yes, I figured as much earlier in the thread and when discussing on the AMRAAM thread.

Oh, and forgot to mention that they would likely increase the thrust a small amount more than what I have in the file to overcome the fact that it lacks the reduction in drag during burn time experienced by missiles. Looks like there is a lot of room for improvement on top of the fact that it can most certainly do 100km provided it has proper battery life.

91

image

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92

That graphs already been discussed before, its from a book that predates the R-77’s entry into service and is likely a guess on its capabilities based on those of the R-27ER, not an actual accurate source.

93

Lines up with in-game testing even before adding the additional thrust for drag reduction during motor burn time and using the AIM-7Fs drag coefficient… and the R-77 has reduced drag in comparison to the Sparrow. So we can expect the R-77 to easily surpass 80km, approaching 100km at those altitudes and speeds let alone higher and at mach 2.

94

nah it seems pretty accurate to the missiles impulse and drag, plus its not like the R-77 just spawned in during 1994, the final prototype wouldve been making flights years before hand. first AIM-120 deliveries began in 1987 though the missile didnt get approved for initial operational capability until 1992.

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95

gaijan doesnt model changing drag at different speeds for missiles afaik, and the R-77 while having much lower drag at high speed also has higher drag at lower sub mach speeds and BVR missiles often fly under that speed during flight since they hit long distance forward shots by collision. So if you average drag between those 2 radicals it may be similar though hard to say since this is basically just vibes based assumptions

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96

RVV-AE trials were ended in 1991, first delivery in 98

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97

R-77 would also have substantially higher base drag from its short burn time

As for it being accurate, it exceeds the stated max range by both the manufacturers parent company and the export company by over 25% and is only ~10% away from the stated max range of the RVV-SD which has a larger motor.

I have my doubts that it performs that much better than the most up to date manufacturer claims, and I have SERIOUS doubts that a hand drawing in a book about missiles prior to the introduction of said missile, regardless of it already existing, with the drawing not even providing altitude, but providing a loosey goosey range estimate of “something beyond 80km” would be an accurate source on range.

I also have major doubts about the grid fins as a whole as they are typically used for ballistic missiles, reusable rockets, or unpowered bombs carried in internal stowage like on the B-2, NOT in air to air missiles. And despite all the advantages they are claimed to have, they are used on the R-77 and R-77-1 missiles only for air to air role afaik, with even the R-77M abandoning the grid fins DESPITE their largest advantage being their packing, which is critical for internal storage like on the Su-57, which they are designed for, and no other nations afaik using them either. It makes me question why they are almost entirely unseen in air to air missiles, even hypersonic ones like the R-37M which would presumably make use of them much better than the R-77.

My theory on the grid fins, through some cursory reading, is that they were more of a holdover from the missiles development, as it seems it initially began development to be the missile of a future jet replacing the MiG-29/Su-27, which eventually became the Berkut and eventually, the Su-57. A key feature here being that both the Su-47/57’s had internal weapons bay which happens to be what grid fins are ideal for (packing). From a quick read, grid fins offer no real drag difference from planar fins at most flight speeds (subsonic or supersonic), offer better drag and control at high supersonic speeds (defined by NASA as 3 < M <5) and SIGNIFICANT drag penalties at transonic speed ( 0.8 < M < 1.3) with it being considerably worse within the 1.0 < M < 1.3 range.

With this information, I suspect grid fins are not typically seen on air to air missiles because air to air missiles don’t typically spend extended periods of time between M3.0 and M5.0. This would explain why something like the R-77M, which I’d bet money has fins designed to fit within the Su-57’s internal storage space, abandons grid fins as its REAL advantage over plannar fins (packing) can be designed around. I also suspect that the advantage of grid fins in drag at high supersonic speeds is likely also drastically reduced, if not eliminated, by the substantial increase in base drag caused by the short motor burn.

I’ll also point out that grid fins drag in the transonic region is SO BAD they are used as airbrakes in application like reusable space rockets.

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98

And significantly less drag above 2 mach thanks to grid fins, hence why I used the AIM-7F coefficient.

99

Karpenko made the graph in '93, no?

100

Yes. At least it’s the year the book was published.

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101

What is your take, should I change anything and re-test?

102

I don’t have anything to add currently

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103

Afaik the fins do not unfold prior to launch, they are manually unfolded on the ground. The switch to conventional fins was an attempt to reduce RCS of the missile itself more so than anything else.

104

Can you make similar for R-27EA

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