What is your take, should I change anything and re-test?
I don’t have anything to add currently
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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.
Can you make similar for R-27EA
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Giving the R-27ER an active seeker and adjusting the weight would be a really simple task actually. Finding accurate information on the seeker ranges and whatnot would be the hard part.
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Really? So with the same drag as the AIM-7F and a lighter missile, it has less than 20km of range on the deck, as the graph shows?
I was primarily concerned with the maximum launch ranges of the graph, but you’re right. The bottom end seems to be far from accurate. There’s simply no feasible way the missile has such low range at that altitude. If you have better information for me to plug in and test please share so we can further our discussion.
I mean there is a very obvious answer- the missile has bad transonic drag and it spends much more time transonic in thick air at low altitude.
The missile acceleration would allow it to exceed mach ~2s post-launch even from 0 launch speed. The thrust to weight is far more than sufficient to overcome wave drag as well, so I think this is more of an error on the part of Karpenko.
It’s possible either the source is wrong, in which case, don’t use it, or your understanding of how the grid fins effect drag isn’t 100% accurate.
Karpenko doesn’t list any launch parameters and such for his source. He only indicated that the missile has a maximum range of 100km . When I was first passed the source it was inferred that it was a primary source. Now we know better, it is not well cited. Regardless, other better (and primary) sources gave me sufficient information to model and test the missile outside the parameters wherein wave drag would have some bearing on the performance of the missile. In these conditions, we can easily show the missile is capable of exceeding 80km range. In fact, if the missile was launched at higher speeds at a higher altitude target it would be more than capable of exceeding the 100km range estimated by Karpenko.
Drag can be a huge factor at low altitude, making missile acceleration much slower, and the transonic impact of grid fins extends well above Mach 1, starting around Mach 0.8, peaking at about Mach 1.15 and then falling off slowly. R-27ER from what I know doesn’t exceed Mach 3 from a low-altitude launch, and I doubt R-77 significantly exceeds Mach 2.
So the instant a source starts to indicate something you don’t like, you turn against it. Wow, such integrity. Shall I also point out that the brochure DracoMindC used to get estimates of impulse gives the launch range of R-77 as 60/20km(presumably head/tail aspect).
In general the biggest advantage of grid fins from my research is not drag at any speed, but rather the reduction in control moment forces allowing for less powerful servos. Which would align with the R-77 having a smaller aft control section.
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I’m not tossing sources I don’t agree with. If that’s what you think, please show me a better one. ROSOBORONEXPORT claims 80km range but the public data suggests the missile has more. Indeed, the in-game testing shows it is more than 80km.
It’s possible you are overestimating the battery life then.
Or underestimating the wave drag, or underestimating the base drag or a mix of all 3.
Incidentally, I was going to try to help estimate gaijins modelling of base drag by checking the Aspide 1 drag (3.5 sec burn) vs the AIM-7F drag (15.5 sec burn) but it seems gaijin has modelled them to be the same, which likely means the Aspide is heavily overperforming
Isn’t it the other way around? AIM-7F is “underperforming” but Gaijin compensated for it by giving it extra thrust.
The Aspide is configured the same (in terms of drag value) as AIM-7E-2 and both have short burn times. The AIM-7E-2 is modeled after performance charts. So it is the AIM-7F that’s out of place.
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I haven’t found a source on it, we know the R-77-1 is 120s based on the video. I’m only looking at kinematic ranges here for the most part. If there is a battery life limitation later it would be an interesting wrench to throw in the mix.
Even if you are only concerned with kinematic range, it is intellectually dishonest to not realize how much the grid fins effect drag.
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The grid fins are a well known and well studied subject, I’ve already explained how the grid fins are more aerodynamic at high supersonic speeds. In fact, the average time to target in my tests suggests the missile spends the entire flight above mach 2 which would indicate it has a drag coefficient lower than that of the AIM-7F’s in-game. I tested it with the higher drag coefficient as to be conservative, and it still performs better than expected with the public data used.
So no, there is no dishonesty. I’m asking for you guys to critique my testing and sources. No one has done this yet, instead they accuse me of being intellectually dishonest without properly reading into what they are discussing.
Very possible actually, didnt think about that
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