1:05 target Su-27 speed 0.8M
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So there is what, some sort of magic Russian sauce that makes their grid fins better than US ones? Despite the fact that American studies were done with at that point knowledge of the R-77’s configuration, and that the R-77 includes no obvious optimizations to reduce flow choke(i.e. sweep of the lattice leading edges, coarse grid geometry).
Also saying “the Russian document” is ludicrous when no-one has even said what document it is, let alone actually presented an excerpt from it.
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Interestingly, we can see the fins maneuvering in the same way the Phoenix does (“X” config) here. I think this is proof it maneuvers in combined plane, should have a 50G overload in-game.
Russian engineer Belotserkovsky is the founder of this technology
perhaps, but I will give no more than 40 on the strength of the case
It does 40G in single plane iirc from the Korean document so presumably if it maneuvers in “X” config it should require a higher tolerance. Or perhaps it is 40G in combined plane, either way it is highly maneuverable.
the fact is that the ratio of length to diameter also affects the strength of the structure.You need to look at books on calculating the strength of rockets
yes Amraam is quite maneuverable
It’s possible it cannot handle higher AoA and has variable acceleration limits for guidance system similar to AIM-54 which maneuvers in “X” configuration as well. It limits AoA based on speed as the instability margins vary wildly from 0.6 - 6 mach.
Sure, and I’m fascinated to find out about the state of the technology in the USSR circa 1985, but you know maybe I don’t think that the resources and knowledge they had is comparable to the USA as of the mid to late 2000’s.
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I won’t remember now I need to get into the documents
Not only is he using drag values from 1985 for his CFD, but the fin design changed since especially for R-77-1 which improves it further. If you have an issue with the CFD, create your own using the US information and then compare to his later.
Also, let’s begin to move this discussion to the dedicated R-77 thread…
there is a new book of the 2004 edition.But it can not be found on sale
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Please let me know if you do find it for sale
I mean the sources I’m citing literally did the CFD(and actual wind-tunnel verification) so conveniently I don’t have to! And they’re also by credible institutions and not some random person on the internet. And they correlate with each other and cite other studies that correlate with them(unfortunately paid-access, but if anyone wants to shell out 25 bucks for Numerical Study on Drag Reduction for Grid-Fin Configurations | Aerospace Sciences Meetings (aiaa.org) and post the details be my guest.
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interesting from just that little information offered. I am temped. Flow choking was a term I was trying to remember the other day. What does the swept back configuration look like? this is it right?
or more like this
The latter, the former is a more recent direction from what I’ve seen.
One of the authors of the paper posts some stuff on his personal website, Grid Fins (marcodebiasi.website)
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That video just shows both sets of fins deflecting at the same time. It doesn’t appear to show the missile rolling in order to maneuver, so it doesn’t confirm it can keep the target between the two missile planes. That seems to be the requirement Gaijin have set for combined plane maneuverability.
The AIM-9L Sidewinder can also deflect both sets of fins at the same time like in that video, allowing it to pull up to 45g. But it cannot roll to keep a target between the missile planes, so the amount of g it pulls varies between 32g and 45g depending on the angle of the turn (most turns it will pull somewhere between 32g and 45g). As a result Gaijin have only given it the single plane g capability (and not even got that correct).
Well, as you know the AIM-54A was doing combined plane (X config, stabilizing roll towards target vector). It is actually almost required of tail configurations to reduce instability caused by the “+” configuration losing lift from one of the control surfaces any time it goes beyond some mild AoA. It is HIGHLY likely the AIM-120 uses such a configuration as well.
I’ll read them in the morning, regardless I accounted for the full range of 0.8 to 1.3 mach in my original comment. (And it was a bit more conservative than @BBCRF 's)
It’s quite dangerous to drop any thing from pylon at this speeds. Shock wave distribution and overflow change a loot. Sonic launch even in 5 gen planes have heavy restrictions on terms g or horizontal (upside down) and vertical (high climb rate or descend).