Even the gridfins on the Soyuz was simply used as deployable stabilizers. They did not deflect they simply deployed as stabilizers. Not airbrakes.
Sukhoi Su-27/30/33/35/37 Flanker series & Su-34 Fullback - History, Design, Performance & Dissection
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A grid of this shape was used as an aerodynamic brake
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A summary is fine. As far as I understand, lattice wings are used best for subsonic and supersonic flight envelopes with poor performance at transonic speeds. While I’m not oblivious it would make for a poor airbrake and its purpose is flight control, does Space X’s specific design of the lattice wings contribute to higher than usual drag on reentry compared to a standard design? I notice they are more curved.
Maybe I am oblivious, I would like your insight.
Interesting so Soyuz Space Capule did. I only find literature stating Stabilizer.
The only mention of emergency air brake is a paper written by a guy in Pakistan in a sigle sentence.
The Drag of the grating depends very much on the relative thickness of the grating profile. The number of plans, i.e. cells and shapes. They can be used both to improve handling at high M numbers and for braking. It depends on which grid you install
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What does higher than usual drag mean to you?
Look at the mass of the Falcon 9. Of course, they need to be larger than the R-77s…
Larger size equal more drag. The Weight & mass of the Falcon 9 would necessitate & larger control surface (Grid Fin). They are optimal for control surfaces at supersonic & hypersonic speeds.
This all comes down to what is your definition of higher than usual drag?
Beat me to it, might as well do the Chinese ones.
relative grid pitch
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The process of stabilizing would happen through the grid fins inducing a very large amount of drag thereby ensuring the aft section of the stack will always point 180 degrees away from the velocity vector. It’s the same principle as seen in ejector seats that deploy a tiny parachute to stabilize the glide until the main parachute deploys
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Mil 157 kg in 48 sec 3,27 kg/s
AB 363 kg in 30 sec 12,1 kg/s
It seems to be fine
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Appreciate that explanation. Make sense.
I believe the increase in fuel I noticed during live matches is rooted in the increased defensive flying. However, I do not feel any increase in performance carrying R-77s as opposed to R-27ERs.
“One after the other” means that STT is carried out on two targets in turn to guide the missile into the terminal semi-active radar guidance stage.
It undoubtedly shows the process of the Su-27 using the N001 (N001V) radar, using semi-active radar guided missiles to attack two targets simultaneously through the TWS + datalink remote control method.
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well yes… like any object.
i’m saying that object of the same size/area can have drastically different drag depending on the “front” facing shape.
(and to add to that; the “roughness” of the “sides” and “back” of the object also matters, like a golf ball and a sphere of the same size/area)
Like this:
Edit:
that is why the “front” of the grid isn’t flat but rather has “peaks” like these:
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fuel lags at high consumption rate at altitude for some reason
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但你需要不断更新数据直到打中目标，先打中远的，然后才是近的
This is because the modification factory changed the R-77 data on the radar to the R27 data, so you can play R-77, which means you have to play R-77 like R27, only one data link, can not be guided at the same time
The data link serves two missiles in turn, rather than serving two missiles at the same time, which can only be said that the J11A foundation is not good, and if it is J11B, there is no such problem
Grid Fins are not used for air brakes.
Soyuz used grid fins for emergency stabilization. There is no such thing as grid fin airbrakes.
The grid fins passively stabilize the spacecraft while the LES is firing during an abort. They deploy by pivoting outward but aren’t otherwise movable.
In an abort situation, the booster may be in the process of tumbling or exploding or both when the spacecraft separates. Having draggy fins toward the back of the package quickly straightens out its flight. providing the maximum separation from the booster during the powered portion of the escape and allowing the fairing to separate cleanly from the spacecraft after the escape tower burns out.
Stable flight of a rocket requires that the center of aerodynamic pressure be behind the center of mass. The Soyuz LES abort has to carry both the orbital module (uncrewed during launch) and the reentry module (crewed) with it because the orbital module is stacked above the reentry module. The service module below that is left behind during an LES abort.
As for the Falcon 9.
No, NEVER. They are not designed with excessive drag. They are specifically designed to control the Falcon 9’s attitude. Pitch, Yaw & Roll.
Falcon 9’s first stage is equipped with hypersonic grid fins which manipulate the direction of the stage’s lift during reentry. The fins are placed in an X-wing configuration and are stowed on ascent and deployed during reentry.
In the atmosphere, RCS thrusters aren’t powerful enough to steer the rocket, and the engine isn’t ignited everytime. The body of the rocket can generate a little bit of lift when moving at the right angle, like a Soyuz. Grid fins are strong enough to resist to the hypersonic flow, that means the air goes by with a speed greater than Mach5 = 6150km/h or, for scientist, 1710m.s^-1. They can control the attitude of the Falcon even at high speeds.)
While the fins are relatively small – they measure just 4 feet by 5 feet (about 1m by 1.5m) – they can roll, pitch, and yaw the 14-story stage up to 20 degrees in order to target a precision landing.
Grids Fins acts like classic control surfaces we can find on an airplane. If they roll 2 by 2 in the same direction (“up - down” and “left- right”) they can control Yaw and Pitch. If you roll the 4 of them in the same direction, the Falcon9 has an excellent roll rate.
SpaceX grid fins are controlled by an open circle, that means that the liquid doesn’t come back in the tanks. During one of the firsts landings attempts, the hydraulic fluid was entirely used and the grids fins were stuck, causing the crash of the Falcon stage on the Droneship.
Theses Grid Fins need to withstand several types of airflow: hypersonic and supersonic, transonic and or course subsonic.
When going through a hypersonic flow, the air goes through the lattice at high speed and isn’t annoying at all because the shockwaves meet behind the fin.
Nevertheless, when going through transonic air stream, the air is going to bounce on the grids and generate a lot of drag and force on the fin. When going close to Mach 1, the Grid Fins aren’t really useful, because the shockwave is located before the grid fins, and no air stream through it equals stalling.
This applies directly to the R-77 as the missile should have zero issue in supersonic flight or demonstrate any issues maneuvering under increased physical vector quantities such those generated in high Mach launches in a dive etc.
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