Judging by the research that you brought. I have never seen such a mediocre performance of the steering wheel. The thickness of the profile c = 0.1 is a lot for a lattice steering wheel
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here’s 2 research papers
PL12 and SD10A keep using the 9B-1103M till 2018
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the 50-65% figure seems ballpark correct, again, impossible to say exactly without CFD. Personally I would have guessed a little higher, but the exact number wasn’t my point, but merely to backup the general analysis you’ve made. Weather intentional or not, this picture captures what’s happening quite well.
To explain it a bit further, the first diagram represents the flow passing through the grid reaching a choked flow state, capped at 1.0M, which means mass flow rate is also capped. This doesn’t mean its a literal airbrake, as in a flat plate, that would indeed be even more drag. because even in the choked condition, as the diagram illustrates, there is a certain amount of air represented by the flow vector, that still passes through the grid, just not everything being asked of it. the remainder must inefficiently flow around the grid, which is where the huge drag penalty comes from.
its only until the the vehicle reaches a high enough Mach number, that shockwaves begin forming which compresses the air, solving the mass flux problem. and even then, the shockfront must be oblique enough, based on the grid geometry and vehicle mach number, such that it doesn’t form 2 shock fronts, thereby double shocking the air (another drag penalty)
Hope this helps.
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AIM-7M:
Caliber 0.2m
Length 3.662m
CxK 2.3
R-77:
Caliber 0.2m
Length 3.6m
CxK 1.85
The numbers that affect the overall drag of the missiles in-game are the caliber, potentially the length, and the “CxK”. As we can see, due to the fact that the missiles have similar caliber and length… the CxK should directly coincide. From this we can tell that the R-77 in order to meet the range criteria given in available datapoints must have a significantly lower drag coefficient, even when lofted.
Additionally, according to datamine information, the AIM-7M has roughly equal deltaV to the R-77… at 955 m/s vs 952 m/s.
Anyhow, what we see is that the R-77 in-game has a 24% lower CxK number than the AIM-7M in order to meet basic range data, even with inefficient lofting that the missile is not known to have. Clearly if the drag of such fins should be 50% of the missiles’ drag this would not work… but it does.
Unless you have performance data of the R-77 to show that the currently available datapoints are vastly incorrect… then the conjecture you’ve assessed without utilizing the better primary data available is nonsense. @BBCRF as you can see, their erroneous assessment doesn’t hold up in practice.
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So the missile will over perform at transonic speeds.
I can live with that if its really that hard to code for the devs. It is in the end just a game, and its overall very far from reality. Also seems like too much work for them to code since basically no other missile we will get will have these type of fins anyways.
Another study out of many comparing grid and planar fins.
Fin models used.
Comparison of the axial force coef during the wind tunnel testing at 7 Mach numbers. Planar fins have an overall lower coefficient.
And finally the composition to see how much the fins add to the axial force coefficient at Mach 3. At 0° we see that clean body has a Ca of ~0.26. and the complete fins rise it up to Ca of 0.52. Compared to the planar fins of the chart above the missile with fins has a Ca of 0.34. At this incidence angle, the drag coefficient of the fins is 0.26 meanwhile the fins is 0.08. Grid fins were responsible for 50% of the total drag force at this incidence angle.
And Drag coefficient plotted against mach number( Ca at 0°)
Not just transonic. more.
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order to meet the range criteria given in available datapoints
Which datapoints?
You are using war thunder as proof it can and you come with this conclusion…
The rank dishonesty here is just hilarious. I know you left this out on purpose.
AIM-120A:
Caliber 0.178m
Length 3.66m
CxK 1.6
So the AIM-120A has signficantly lower CxK… and it is also smaller. For those who don’t know(which MiG-23M 100% does, btw), smaller missiles have higher CxK. For instance the R-27R has a CxK of 1.9 and a diameter of 0.23m, but the 0.26m R-27ER has a CxK of 1.455.
So for the AIM-120A to have a lower CxK despite being smaller means in effect it is much less draggy. Hard to say exactly without knowing why this occurs in Gaijin’s model, but it’s there, and any sort of testing of the missiles shows this.
As for why the AIM-7M has such a higher drag, it’s because its wings are so much bigger. The body wings have a wingspan of 40 inches(100cm) and a chord of 18.6 inches(47 cm), and the tail 31 inches(80cm) and a 18.5 inch chord(47cm). The R-77’s midbody strakes have a span of only 40cm, if we say they have a 65cm chord that means that the AIM-7M’s wings have 45% more area than R-77’s. I’ll leave it to others to figure out what the reference area for the R-77’s grid fins is in comparison, but I would bet it’s smaller as well.
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I compared two missiles’ of equal values that have an effect on the CxK so you can see that the R-77’s drag is lower comparatively. This is nothing but an honest comparison. I explicitly stated that the CxK is comparable between the two BECAUSE the other values are very very similar.
You want to believe what the others are saying that the grid fins should account for 50% of the overall drag of the missile, if this was the case it should be higher than the AIM-7M. The area of the AIM-7M’s wings is bigger, this is true… but is it 25% higher overall drag than the R-77?
Please address my argument instead of comparing other designs with relatively higher CxK. The AIM-120 has a lower CxK, this is not entirely unusual. The fin angles of attack and available overloads are far less on the missiles with higher CxK. What we could be seeing, and why the R-77’s overall drag is lower is an attempt at getting around the inefficient lofting and more specifically, the wobbling issue that is causing the performance in-game to become erratic depending on conditions. However, I would remind you that the AIM-7M and R-77 have VERY similar caliber, length, overall deltaV. The R-77’s performance data suggests that even without lofting, the missile has equal to or better range. If the grid fins were so much more detrimental, this would not be the case.
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Seems like the Meteor missile has a very thick booster smoke but the ramjet is smokeless. 2-2.5 seconds of thick smoke and an immediate difference of no more smoke after those few seconds, indicating that the ramjet has started. It’s also clear that the booster has an absurd acceleration to get it up to speed.
(Timestamp of 1:35)
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Even slowed, it appears acceleration is less than initial for AMRAAM or MICA imo
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I mean 45% > 25% So it is perfectly consistent that the AIM-7M’s planar fins can have lower drag coefficients but the missile has more drag because it has large wings. And also you yammer on about how similar AIM-7M is, but there’s another big difference: Sparrow is a wing-control missile. That makes it aerodynamically very different from tail-control R-77 or AIM-120, but the game doesn’t explicitly represent that so CxK is forced to swallow that difference as well.
MBDA did state that Meteor missile does worse than MRAAMs in the shorter ranges (I presume it to be less than 30km), so that is expected.
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You’re ignoring what I asked. Is the overall drag of the AIM-7M frontally going to be 25% higher than a missile with grid fins? Let’s specify at their top speeds for comparison, as we know the grid fins will have a higher coefficient in transonic region. We can assess them at mach 3.
You claimed they have 45% higher wing area, I have not checked your math. Assuming that is 100% accurate… it is not all exposed looking at static conditions. Is the frontal area higher or lower than the R-77? Looking past this - is the drag going to be higher or lower when the CFDs and studies for grid fins are accounted?
When you come up with the answer, explain further how the R-77 matches or exceeds the range of the AIM-7F/M in spite of a boost only motor and higher drag?
Yes, the initial speed on Meteor is lower than that of AMRAAM (and similar missiles). Once the boost stage of those missiles burns out Meteor rapidly overtakes them though:
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I think it is pretty reasonable it will be, given its wings are much bigger. Sparrow is also a very old platform with aerodynamics that date to the 50’s, so chances are there are further inefficiencies in terms of how its wings/tail interact with the body and each other.
Do you think that because wings do not have huge frontal area they are dragless? They are not, especially at supersonic speeds where wave drag is an issue. Gravity also exists, so the missile must always have some AoA in order to generate lift and airborne. That you ask about frontal area is really revealing as to your actual level of knowledge here.
Body shape is similar, has few protrusions, and the wing was been re-designed periodically over time. Even the various lots of AIM-7M have different weighted wing tips depending on variations for improved stability. To claim it’s 50’s aerodynamics would suggest that few improvements were ever made since.
Now, you could argue that while the body shape is similar the AIM-7’s middle wing being the control surfaces is outdated but again… that doesn’t change the fact that the static drag coefficient is higher than that of the R-77 in-game. Performance between the two doesn’t suggest any kind of severe detriment regarding overall drag.
You are trying to argue the maneuvering energy loss when addressing a static coefficient used to calculate drag without factors such as fin deflection.
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