Why R77 doesn’t have any sustainer? Is it historically accurate?
seems like AIM-120A AMRAAM seems to hit a lot sooner than the R-77
of all FOX-3, the R-77 is the worst, with the MICA being the best
The file data shows the length of missile, seeker performance, and engine performance matches standard R-77 / RVV-AE. Not R-77-1. Must be error in missile 3D modeling.
R-77 shouldn’t loft.
I think they modelled it, the R-77 has the most drag than all the other ARH missiles, and in side by side test firings it slows down much quicker and sooner too. For reference compared to the AIM-120 the R-77 has a higher drag coefficient value and higher diameter (typically for BVR missiles with larger diameters they have lower drag coefficient values).
Do you know what the pros/cons of the fins of R-77 are compared to normal fins? All I can find is more drag
The grid fins are more efficient at supersonic speeds however at sub and transonic speeds they act basically like airbrakes. If I had to guess I’d say at supersonic speeds they can provide higher lift-drag ratio but that quickly gets eaten up by the drag at any reasonable speed
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main pro is they require much less power to torque the fins which for soviet missiles was a big deal since battery limitations were always a problem. Also lighter weight electronics necessary to torque the fins.
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Doesnt the missile stay supersonic %90 of the time anyway? You wont be firing it while going 200KMH
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If you’re flying at M1.2 @ 30k against a co-alt target, yes. If you’re down low after defending and lining up for a snap shot the missile is going to start subsonic and stay subsonic for a pretty long time. All of the stats you can find on those missiles are from test shots at speed and altitude. I am not sure how much WT models it but in DCS for example launching a phoenix at M0.95 and M1.05 results in a pretty noticeable increase in range as the missile doesn’t hit the Mach barrier under its own power. The R77 is a decent (at best) missile under ideal conditions but the drag fins really hamper it in a realistic launch scenario. There probably is a reason the idea for grid fins was abandoned with the 77M
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Significantly reduced drag at high supersonic, equal in subsonic and only briefly does it have significantly higher drag in transonic region. They offer significantly improved stability and AoA over traditional fins but also a much larger radar cross section.
They modeled it with the lower end of thrust values given and the lower end of drag from my already extremely conservative estimates.
If we bug report the incorrect lofting they’ll need to increase thrust or reduce drag to meet the same performance metrics which should fix the missile.
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Significantly reduced radar cross section for these missiles is the primary reason. We have gone over this already.
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For some reason I trust DCS a wee bit more than your numbers, as for the grid fins, they act like bricks at subsonic speeds, nowhere near “equal” to normal fins. I’m not even sure where you got that from
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That’s from most well sourced studies…?
They’ve been posted here several times.
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the DCS R-77 isnt a good example, its on an ancient API from the Neolithic era and is really poorly modelled as a result
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So if you are firing from Mach 1+, and you don’t care about stealth, R-77 fins are better than conventional fins?
I do recall someone posting a paper here from the early days of the new forum showing that the grid fins were lower drag than conventional fins at subsonic and supersonic speeds, but higher drag than conventional fins at transonic speeds (something like Mach 0.8 to Mach 1.1).
Also, once the missile drops down in speed and gets close to the target, it would be in the transonic region where the higher drag would allow it to maneuver better and have a tighter turn radius in the critical moments before making contact.
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İt’s russian so everyone has to bash it, because Russian engineers couldn’t realize basic drag stuff about physics so they added garbage fins, while it was obviously a design choice with a goal in mind with some trade offs
Yes, that is the case.
Additionally, unlike all of these other missiles in DCS… The R-77 hasn’t been updated in like a decade. Newer information has been learned or revealed since about its’ performance.
This is important to note. They increased maneuverability while reducing cost and complexity. They knew it would hamper transonic drag … the benefits out weight the negatives, tho.
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The argument about lattice fins has been had over and over. There is a good reason why the only 2 air to air missiles that use lattice fins are the R-77 and R-77-1.
Here’s an exerpt from a 2006 paper from NATO regarding the use of grid fins for air to air missiles:
Here is the PDF in question: Defense Technical Information Center
TLDR: Lattice fins for air to air missiles look like a good idea at first, but are actually terrible. They are however undisputed kings of drag braking devices and stabilizers for bombs/dispensers.
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