Yes, there’s a bit of explanation here: Community Bug Reporting System
You are. You were oh-so-happy to support the chart when it agreed with your conclusion, but now that I pointed out that the performance on the deck indicates serious drag issues, you are tossing around reasons to discredit it. It is obvious, obvious intellectual dishonesty.
Here, have an obvious critique: the missile’s average velocity will be very different from the amount of time it spends at any particular velocity. Let’s say the missile accelerates to a speed at burnout of Mach 4 at 15km, about 1200 m/s from its starting velocity of 339 m/s in 4.5 seconds. It travels a total of 49 km, about 45.5 after burnout. Treating the drag as a function of v^2 times a constant, we can say the missile impacts traveling about 340 m/s, or mach 1.15, and deccelerates through Mach 1.5 at 50 seconds after burnout, and Mach 2 at around 30 seconds. So the missile actually spends a great deal of time at speeds where the drag impact of grid fins is signficant.
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I saw sources that suggested ranges greater than 80km, it does not make sense for the missile which on paper should clearly outperform the AIM-7F (with 98km kinematic range). This source claims 100km, and was originally shown to me and referred to as a primary source. Once it was shown it was not a primary source I discarded it as a primary source. This is not intellectual dishonesty at all.
Later on, when I had found sufficient (more proper) sources to model the missile and test it in the game I did so with extremely conservative values. I gave it the higher drag coefficient of the AIM-7F, and I did not increase thrust in consideration of the reduced drag during motor burn time. Despite these drawbacks, the missile performs better than expected based on other public sources… and in fact better than Karpenko had thought as well. I imagine with the lower drag and higher thrust it will perform significantly better still. You’ll need to calculate the drag model of the missile before making presumptions on how fast it loses speed. I’d welcome the analysis.
You already knew all of this though, I’ve said as much and now you’re being intellectually dishonest. Please take this discussion more seriously, I’m not going to feed trolling any further.
He’s continuously played with sources, tried to pass of questionable sources as fact, modified his analysis of the missile, etc… all to suit the “the R-77 is equivalent to the AIM-120-C5 and can exceed 100km easily” idea he’s been set on.
Its why I’ve blocked him so I dont waste more time arguing with him. There is a very VERY clear bias towards proving the R-77 is vastly superior to what its official numbers say.
He’s even accused Rosoboronexport and KTRV of reverse propaganda, which was an… interesting… argument.
The fact of the matter is, grid fins primary advantage in drag are at speeds air to air missiles simply dont spend much time on, and having the missile kneecap itself hard in terms of drag and controlability at transonic speeds also seems questionnable as a design decision for air to air missiles. Grid fins offer hinge moment advantages which requires smaller servos for deflection at high supersonic speeds, and packing advantages which was likely the initial reason for their design as the missile was allegedly initially designed for jets which would carry weapons internally, but dont seem to offer much real advantages over planar fins otherwise.
Grid fins have been under reasearch for decades and have been used rather extensively for ballistic missiles and re-entry vehicles, both applications spending a large portion of their time at high supersonic speeds, and one of which (the reentry vehicle) likely enjoying the massive drag during transonic speeds for reentry, but have only been found (afaik) on the R-77(-1) with ALL other air to air missiles, of varying speeds and ranges adopting standard planar fins instead.
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I’m using your own data, go ahead and give me an arbitrary drag coefficient to test and justify it, we’ll see how the missile performs in that scenario.
In fact, give me multiple scenarios to test with this data and I’ll test it.
Better yet, you can test it yourself and if you’d like to know how or participate instead of trolling feel free to DM me so we can get it set up for you.
No, I don’t, because it’s well known that drag is a function of v^2 at high velocities like this. The missile flies a straight trajectory at low AoA for its flight, so we can essentially reduce this to a differential equation problem. There’s literally one drag coefficient for Gaijin’s missile model, so this is the best we can do.
What is the point? There’s plenty of research evidence that grid fins have a strong change in drag around transonic speeds, different from that of conventional fins. Because of this there is no value for Gaijin’s drag model that will produce appropriate results, presuming it’s tuned for conventional fins and has correct transonic behavior. Which maybe is worth a bug report itself given R-77 is likely to show up soon.
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I am sure Gaijin can easily model the wave drag issue, but it is not so much a concern for the time being.
Regardless, you have provided zero proper sources and no better information to test. Instead you’ve just made accusations and spammed up the thread with more useless bickering instead of assisting further with the research. If you have any real suggestions as to how we can further test the missile please forward them. Until then, I’m not going to continue entertaining your nonsense.
Even with the conservative figures, the missile well exceeds the performance of the AIM-120A as tested in my other thread. Everything so far has aligned itself with my original hypothesis that the R-77 (RVV-AE) has performance much more in-line with the AIM-120C-5.
This thread exists because you have a particular case to make. The timing on that should be obvious to everyone. You can quit hiding behind “it’s about assisting with research.”
WRT grid fins, this is well-studied. Take a look at https://apps.dtic.mil/sti/pdfs/ADA426637.pdf or https://arc.aiaa.org/doi/abs/10.2514/6.2000-937, or Analysis of Grid Fins for Launch Abort Vehicle Using a Cartesian Euler Solver (nasa.gov). All indicate that grid fins experience signficantly increased drag at transonic speeds.
That you uncritically swallow your first-pass results because they align with the conclusion you expected is obvious and a huge point against your analysis. You complain about how everyone keeps bringing up the chart as a non-primary source you thought was primary… well maybe you should have been more cautious. And the fact that you weren’t indicates that you’re biased.
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There is no case to make, the data shows what it shows. If you have data with more credibility or want something further tested please make it evident. I was given the source by someone who perpetuated it as more credible than it really was. I thought I was being cautious, and indeed it was wrong. I corrected it myself once it was made evident.
That source is not used in any of the data or testing done since, rather just referred to as one of the first times someone was remotely correct about the absolute maximum launch range as evident by the subsequent testing.
Should I model the drag as higher than the AIM-7F’s and if so, what do you think is a reasonable coefficient? How much should I increase the thrust to overcome the drag reduction not modeled during motor burn time?
These are questions that will further the testing. If you’d like to help, help. Anything else such as these ridiculous accusations does nothing for the purpose of the thread. It’s not even relevant to the topic.
If you want some actual advice, use the pamphlet that @DracoMindC posted. That gives a 60km head-on range for R-77. Figure out the conditions based on the R-27R and R-27ER there, then figure out the drag coefficient from there.
I’d say my accusations do something very valuable for the thread: they inform everyone else that you are not to be trusted. You don’t get to claim that people pointing out your errors and biases and holding you to account for them are off-topic, especially when your case depends on your own original research effectively.
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All information used has been provided by you guys. The source that stated 100km was provided by y’all and posed to me as a primary source. When I posted it, the same people then ridiculed me for doing so and portrayed me as dishonest. This isn’t the first time someone has done this to someone, won’t be the last. My opinions about the missile’ performance have changed based on the information provided and I’m not holding out or trying to make it meet some standard I have in my head.
Instead, I have continued to ask for you to bring forth sources in good faith and yet because this is an English forum I have noticed a trend. When someone asks for eastern or more specifically, Soviet and Chinese missile information… it is not provided willingly. One must research for themselves. When I ask for evidence that the AMRAAM can exceed “X” range, it is provided on short notice. The only bias I’ve seen here is from the community whom desperately wants me to not post these results. They don’t want to believe that other countries (especially Russia, China) have capable ordinance.
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Or, as a much more reasonable cause rather than an accusation of bias, maybe the reason is that on this English-speaking forum, most users do not have easy access to or ability to interpret Russian primary source documents?
This is also a blatant attempt to shift the burden of proof. You’re the one claiming 100km range, prove it. Go find some source documents. People have posted sources, for that matter, that show less than 100km range, but you consistently try and argue against them, rather than accepting the evidence. That’s not good faith.
Участие самолётов Су-35 ВКС России в специальной военной операции - YouTube
This video’s an interesting take, R-77-1 with loft and a more powerful motor has against a target on the horizon 90km DLZ, when launched at 12.9km and mach 0.95. This is another thing to toss on the R-77 having 100km range being very suspect- the R-77-1 should have a considerable range advantage and yet even in a hot, high shot lacks 100km range(and requires 100 seconds to travel around 50-60km).
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I am not claiming, that is what the results show. That is what they suggest. Already, the primary sources stating information on the missile show the weight and size is not indicative of a missile with such short range. The secondary sources with credible information such as CAT UXO and the one Gaijin has used so far show the thrust, burn time of the missile is more in-line with a missile that has >80km range. The only exception might be excessive drag coefficients but I have not gotten anything from you when I have requested this. You have the sources, but you have not made any suggestions as to how I should modify the missile file.
The sources that state less than 100km range have not yet provided any semblance of launch parameters. If the missile in-game with the AIM-7Fs drag coefficient and without the additional thrust to overcome the lack of reduced drag during burn time is reaching 75+ km at just mach 1 launch and 10.5km altitude… surely even a hefty drag penalty will not stop it from doing >80km at mach 2 and with nearly twice the altitude.
Conveniently, in that video target information is not presented. We do not know enough information to make a direct comparison and I’ve honestly already tried to make one with the other videos presented. The results were inconclusive due to lack of information.
Do you really honestly believe this missile’s maximum range is only 80km with this information? Seriously? You say I’m turning the tables to shift the burden of proof but you’re presented with this information and it astounds me that you’re not on the same page as me. It’s evident that the missile short of some significantly shorter battery life should be capable of exceeding 80km in such scenarios.
It generally appears that you hopped on Wikipedia, saw the claimed range, and have since done everything short of going to russia and hunting for primary sources to prove Wikis erroneous claim.
That’s an interesting claim seeing as all the data used in the custom missile file and testing has since been provided by y’all. Oh, and wiki claims 80km just like y’all did.
https://cdn.discordapp.com/attachments/955829235493273680/1145170593562509432/image.png
I’m here to find out what the real performance of the missile looks like. My original claim was that (imo) the R-77 has range more comparable to the AIM-120C-5 than the earlier AIM-120A/B. This is also based on testing over in my AMRAAM thread where I’ve cited sources for all the metrics used in the testing. Since it’s a more conventional missile, and is American, I have not gotten nearly as much kickback.
It’s also annoying that y’all keep dragging my character and forcing me to come back and defend myself over this. The data is here, you guys aren’t directly denying the results of the data and instead are attacking me for believing the results despite them being contrary to the seemingly popular opinion on the maximum range of the missile.
Your results aren’t worth shit because the drag value is arbitrary. Like ingame the CxK values range from 1-3 and there’s no clear correlation as to why. The TEMP has a lower drag value than other sparrows. R-23, R-24, and R-27ER are all over the place. There’s no grid-finned missile ingame, so it’s impossible to make an actually appropriate guess at what the drag ought to be. You’ve just grabbed a CxK, got results you like, and biased your way into thinking that’s good.
I gave you a way to try modifying the missile file, and you ignored it. If you want “a number” then maybe if we compare Microsoft Word - Draft-Final-Signed.doc (dtic.mil) and /tardir/tiffs/a384590.tiff (dtic.mil) we can take a stab, the AMRAAM model had a peak parasitic cd0 of 0.45 and the grid fin missile 0.69. So proportionately we might guess that increasing the CxK by a factor of 1.53 might be an appropriate correction, which would give something like 3-3.5 CxK That is really just a WAG though.
We know it’s a hot target because the bugged target has a vector indicator. And like, even for a slow target the time of flight to 50-60km is quite long. I very much doubt that a target clearly above the horizon would be going much slower than Mach .8 or so, given how valuable speed is for BVR. Again, you see something that disagrees with you and dismiss it. And yet you were not so discerning when presented with evidence that supported your preconceptions.
100km is an arbitrary number. I’d believe it if the missile was thrown by an aircraft at a high enough altitude and speed(like a Mig-31 or something), a command/active missile’s range isn’t capped by seeker limits. Now what I don’t believe is that the missile has more than a slight advantage over the AIM-120A/B(I do think that it’s credible that the R-77 has some advantage in a very hot/high shot). In an ordinary BVR shot, that is not doing too much more than Mach 1 or at extreme altitudes, no, I don’t think more than 100km.
Well, if you didn’t want to be attacked about your character, maybe it would have been smart not to do so many things that put it in question. Also double standard much? You have had no compunctions about attacking the character of anyone else.
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Your opinion is arbitrary. My drag coefficient used is based on facts. The missile diameter is the same as the AIM-7F. The drag coefficients in-game are pretty linear and affected by more than just the number. They are affected by caliber.
The R-77 has slightly smaller diameter irl, and the same in-game (200mm). Lower drag wings, and the point of contention is on the grid fins. Using the same coefficient as the AIM-7F is actually quite conservative imo. If you think otherwise we can probably math it out once the CFD is done by the DCS devs. Until then, I’m inclined to believe that the drag coefficient I used netted a conservative analysis of the data.
Heck, I can even test the missile with the obscenely higher R-23R drag coefficient of 2.55 (vs 2.3 for AIM-7F and 2.1 for R-24R). I’ll even test it at an arbitrarily huge number like 2.75.
Iteration 1 test, 2.3 drag coefficient (75km in ~79s) Direct impact.
Iteration 2 test, 2.55 drag coefficient (75km in ~80s) Direct impact.
Iteration 3 test, 2.75 drag coefficient (75km in ~80s) Direct impact.
Iteration 4 test, 3.0 drag coefficient (75km in ~80s) Direct impact.
Seems that Gaijin models very little drag at altitudes of 15km (crazy, I know). Could be other issues with the testing though if there is an issue. I saw the edit to your last post about the CxK and I can do further testing with 3-3.5 CxK though I really doubt it could be that high as the average would be lower due to the reduced drag during periods above mach 2 in comparison.
Also, a reminder that I have yet to adjust the thrust to account for the reduction in drag during burn time. Do you have a recommendation for how much the motor would reduce drag during burn time so I can adjust the thrust?
-edit- I have added the 3.0 drag coefficient test.
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I wouldnt pay much attention to the head on ranges given they are for slower launch speeds and arent a max range, for example the R-27R is given a head on range of 60km, but the R-27 user manual gives the R-27R a maximum range of 90km (which is at a very high altitude and launch speed)
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Facts? What facts? I see a whole lot of supposition and very little in terms of actual facts. For that matter CxK isn’t the only parameter that needs looking at- you could note that there’s also max Fin AoA, wing area mult, max lat accel. I don’t think there’s any clarity at all to how these values impact performance or what they ought to be set to.
Also I like how you’ve realized that having such widely varying coefficients have almost no impact on range is highly suspicious and suggests that there’s something being missed, but proceed to just dismiss it as drag being ignorable at 15km. Like air density is 1/6th that of sea level at 15km, which is less but that drag coefficient has no impact at a point where the air is still reasonably dense makes me suspect there’s some major error here. Particularly given that obviously the missile slows down a great deal from its peak speeds given the overall flight time.
If you want to do a sanity check, make the CxK like 30 or 100 or something and see what happens.
