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
Sukhoi Su-27/30/33/35/37 Flanker series & Su-34 Fullback - History, Design, Performance & Dissection
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.
1 Like
He is gaining speed, it is necessary that he does not do this
You don’t understand what you’re writing about.
Depending on the design, they can act as an aerodynamic brake.
3 Likes
There is no such thing as a grid fin airbrake. Makes zero sense.
My apologies, you are right about things here and there. Matter of fact very often. I respect what you post most of the time, even now. You always bring a unique perspective. I admire it. But like all of us we get it wrong once in a while.
You would not let me go on incorrect about something, right? Why would I let you? I appreciate correction it’s how you learn. You should too.
Soyuz did not need to slow down in emergency abort. They need to straighten & stabilize in a emergency. A higher drag grid fin accomplished that immediately.
Having draggy stabilizers toward the back of the package quickly straightens out its flight & provides 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.
Without the fins, most of the pressure would manifest at the point where the base of the LES tower meets the top of the spacecraft fairing, above the orbital module. The center of mass is near the top of the orbital module when the LES is ignited, moving backwards as the LES rocket propellant is expended. With the center of mass behind the center of pressure, the stack would be unstable. Adding the fins moves the center of aerodynamic pressure back, yielding a stable configuration.
I just showed you a diagram of the Soyuz in English and Russian. Did that say Stabilizer or Air Brake?
стабилизатор
РС-grid stabilizer
1 Like
Whats under that redline?
6 Likes
numbers
2 Likes
Quick question: Are you capable of understanding english sentences?
Because through the whole thread you always seem to completely misunderstand every source you look at and take things out of context whenever you feel like it.
The sentence you quoted is literally confirming what MiG-23 said, namely that SpaceX does NOT use any russian parts.
They had an opportunity BECAUSE they didn’t use them. Their competitors did so they had a problem, SpaceX did not. The only way they could have had this opportunity is with them not relying on any russian tech.
3 Likes
“can act as” and “are designed for” are two completely different things.
i think you two are discussing different things and trying to read the others texts as if they are about your thing and not theirs thus believing they are wrong.
When in fact i think both if you are correct.
-Grid fins are DESIGNED for guidance and steering.
-They INDUCE DRAG and have the POSIBILITY to be used as airbrakes if needed (even though that isn’t the primary use) by angling them to counteract each others rotational momentum.
Grid fins are not used as airbrakes as their ONLY function in any application where they are present. That would be an extremely bad design choice as there are far more efficient airbrake designs out there.
Non-moving grid fins are used in the exact same way the back end of a dart is; To use the off-angle induced drag to create momentum to right-angle the object whilst moving.
if you design them to be airbrakes then they are no longer grid fins.
no one designs them as air brakes.The “air brake” and the lattice wing is a conditional concept. Since it is possible to make a wing with a large resistance, or it is possible with a small one.
At the same time, they are also used for stabilization and control
And now calculate the thickness of the aerodynamic brake, the fastenings, the power of the hydraulic cylinder that releases the brake and the weight.And you’ll realize that at such speeds, a grid with a lot of plans and a thick profile looks better
How in the world is that nonsense?
no need for the attitude man.
well… again, why the attitude?
i fail to see in any way what so ever how i wrote anything wrong here.
It isn’t. you can’t change the name of something depending on what it does in the moment. it’s designed and named for a primary purpose.
I can use a plastic bag as a parachute, but that doesn’t make it a parachute.
I can use a fork to cut something but that doesn’t make it a knife.
Just because they can be used as brakes doesn’t inherently make them brakes.
at hypersonic speeds yes, but that isn’t its primary purpose. The primary purpose is guidance, that is why they are named fins instead of brakes.
The breaking is primarily done by angular re-entry, making the density of air increase at a slower rate than a straight entry would, utilizing the body of the craft for friction and at times of peak acceleration (or deceleration need) using the engines.
I don’t think the discussion needed to progress this far, Ziggy already proved himself wrong and followed it up with “I was always right”… Twice… Lmao
Let us focus on the Su-27.
5 Likes
Sometime ago I found a list of Su 27 accidents but I don’t know where , does anyone know where to find it ?
But you can make stabilizers with increased aerodynamic drag.
1 Like
They don’t understand that grid fins are more easily used in multiple roles than conventional fins. Let them be ignorant.
2 Likes
Which is exactly what my first reply to you was about?
@MiG_23M
i have made no claims as to anything to the contrary.
You replied to BBCRF and then tagged me…?
because you commented on his reply to me. so i answered you as well.
1 Like