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Doesn’t this assume that the airflow is uniform(e.g. is not being disrupted by anything upstream)?
The bow shockwave creates a flow boundary with subsonic air downstream and surfaces behind it like the strakes in the R-27’s case obviously have some sort of impact on the flow otherwise they woldn’t be included.
As an aside I did find a somewhat tangentially related paper (Effect of Tail-Fin Span on Stability and Control Characteristics of a Canard-Controlled Missile at Supersonic Mach Numbers) looking at the Sidewinder(AIM-9J / -9P) under similar circumstances
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You’re missing the point that Ziggy claimed initially that the fins created zero lift whatsoever only to transition his argument towards claiming that equal lift both above and below the wing would hold it steady in level flight… somehow counteracting gravity without some form of positive lift.
He went as far as to claim initially that the tail section creates lift and the “rudders” (wings) don’t create any lift at all. This is in spite of the fact that they share the same type of supersonic diamond shaped symmetrical airfoil.
Anyhow, BBCRF was just using the source above as reference to indicate that when we refer to lift it is generally towards “positive” lift and not the net-zero lift applied at zero angle of attack for such an airfoil.
You do not understand what Lift is & what flight control surfaces are because you do not have an education outside of K-12. Even when armed with the full weight of the internet at your fingertips you still cannot comprehend what they are.
You continue to troll and derail anyone from discussing & seeking the truth of a matter with your poor comprehension just to be right.
Supersonic compression is how lift is generated at the speeds the missile flies.
Secondly, you do not know English or even the Russian meaning of the word Rudder. A Rudder does not mean wings!!! hahaha!
Rudder is just a generic term for steering in both English and Russian. Even an automobile’s steering wheel is sometimes referred to the rudder informally.
The formal definition in both Russian and English as follow: A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, airship, or other vehicle that moves through a fluid medium (usually air or water). On an airplane, the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane.
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The “tail section” as you try to refer to them is the wings. Even your “Google patent” states this.
The R-27s wings is a modified-double wedged clipped delta. They are diamond shaped at the tips to produce lift in supersonic flight. I can name the exact patterns on the missile. You cannot.
The “rudder” is the control fins and they are flat, they do not produce enough change in pressure to generate lift, only to steer the missile. That is why even your source uses the word rudder. It controls the ability to “steer” the missile.
They are both symmetrical diamond shaped airfoils, neither produces positive lift until it has some angle of attack.
You can see the ridges that form the “diamond” along the base and it extends at a slant towards the progressively thinner tip. The tail remains uniform in thickness along the thickest point from base to tip but not along the length.
Even the destabilizers have a very small degree of “camber” (diamond shaped, since it is a supersonic airfoil).
The shape, design, and use of the wings (‘rudders’) are well known and your explanation is nonsensical. Anyone can very clearly see the wing is not flat and has chord, therefore also produces true lift when angle of attack is applied.
The source says rudder because that is the translation to English. The use of this word in the Russian language is used to describe lift producing devices that can pivot whereas standard ‘wings’ do not move. This is why the wings of any missile are called “rudders”. They refer to the tail section of the AMRAAM or other missiles the same.
Would the pressure differential above and below the fins (at 0 degrees AoA) cause any non-negligible lift? Not entirely sure what the thread argument is, this is more a general question.
If the airfoil has equal camber on both sides, airflow will not be going faster or slower on one specific side. This will cause equal amounts of lift at 0 degrees AoA. The airfoil requires some angle of attack to produce positive lift.
Wrong, you do know what how lift is obtained in supersonic flight. Get an education.
Even your own source states there are only 4 wings. Can you point directly to them?
Rudders are not wings & do not provide Lift for the entire aircraft in any language. Even your own source. Nice try.
This is the part you will continue to spam more false information to drown out your lack of education, right?
There is no camber you are making that up. Supersonic airfoils do not have camber. You do not understand the word camber means either.
There is no curvature, convex or rounded arch to their design but straight angle edges.
Because that would cause wave drag.
This discussion is far beyond your comprehension. Just admit it. Move on with your life. It would do everyone including yourself only positive.
The source uses this word for the wings in the middle of the body, “рулями”. This on its’ own is “steering wheel” when translated directly to English.
When they reference them however, they mention them as “isolated” in the sense that each has an actuator that rotates on its’ own and they are not connected. When you translate this full term, 'изолированными рулями" it becomes “insulated handlebars” or “isolated rudders” in English.
In the context of the sentence it is generally translated by translation services such as Yandex as “isolated rudders” or just “rudders”. These are wings.
They have a supersonic diamond shaped camber airfoil - matching the ones at the rear with the exception that they get thinner towards the tip as it gets longer. It is a unique airfoil design and the reason they chose this was outlined in the patent.
Even in the patents’ own translations these funny terms are seen. Your inability to understand that the translation does not mean literally that they are ‘rudders’ does not change the fact that they truly are wings and produce lift. You initially claimed they did not produce any lift at all and that the “air pressure” produced by the fins at angle of attack was not the same thing as lift.
Right, the camber line is the correct terminology for the shape of the exterior portion of the airfoil. They are supersonic airfoils, hence the sharp leading and trailing edges with the double wedge. Here is an example;
This is clearly seen in my above post.
They are convex by nature as they have interior angles less than 180 degrees. This is the leading and trailing edges which form a sharp point to avoid a boundary layer of air.
You are literally claiming that these are not supersonic airfoils and that they server only to act as a “rudder” based off your misunderstanding that the translation must have been literal. You clearly learned any of this information in the last week after the fact that you claimed it wasn’t a real airfoil but a flat fin.
Simple google search would have shown you pictures of the fin where you’d have been able to view the supersonic airfoils’ shape.
You are having a total meltdown and contradicting your own statements. Its rather sad to see.
I did not ask you to explain your logic. I asked you to point to the 4 wings on the missile.
Just answer the question.
Where are the 4 wings located in your mind?
Point to them.
The translation clearly explains that there are 4 fixed wings and 4 aerodynamic wheels (movable wings).
I beg to differ, they are not flat plates either even on the wings at the rear. There is curvature to these wings plates. They are more complex than a simple flat 2 dimensional shape as you want to believe. Certainly more modern and complex than the simple AIM-7 style double wedge airfoils seen in the mid section.
You’d rather I stop debunking your absurd statements.
I actually find it humorous - your claim that it doesn’t produce lift because it is a flat plate (it isn’t) is also wrong because a flat plate style fin ALSO produces lift. The expansion fan is seen when AoA is applied at both the leading and trailing edge.
@SpeclistMain To further answer your question see the above photo. The wings of the R-27ER can be categorized as the double wedge supersonic airfoil design whereas the tail is more of a hexagonal (modified wedge) design. These are on the bottom left and bottom right of the image respectively.
The wing at the rear produces two expansion fans, and is much thicker. The lift provided from the rear is more than from the front. This is required as the missile needs to remain statically stable with the ‘rudders’ (movable wings, control surfaces) being further forward and closer to the center of mass.
I will ask you again, where in your mind is the 4 wings located in your mind.
Point to them.
What is this magical nameless tail section I keep referring to?
I do appreciate that you are adopting my classification of the airfoil. Thats a start, but that description is for the “tail section” not the control fins.
“Movable wings” is not an actual definition in aviation.
Just a made-up word in your uneducated mind.
Variable Sweep Wings & forewings of an aircraft are the only wings that can actually move.
The R27 has 4 aerodynamic control wheels. I love how you left out the word CONTROL.
You intentionally left out their only sole purpose. For control. Not to provide lift. That is why they are not called wings but referred to as rudders.
Rudder is a generic term used to control steering.
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The full quote:
The tail section has four fixed wings and the movable wings are placed in the mid section. The total number of airfoils on the design is actually 12.
You did not classify anything, rather are using more complex terminology to put forth a pretense that your original arguments were valid. They were not. You did not think the movable wings were an airfoil so we must be getting somewhere.
I have highlighted here the airfoil from side-view. This is also visible in pictures (please see below).
Below this is another supersonic wedge shaped airfoil from top view with the same portions highlighted.
The leading edge is red, the wing is yellow, and the trailing portion is blue. The yellow section could be considered the “point” of a normal diamond wedge shaped supersonic airfoil.
Now, according to those shapes the correct terminology for the airfoil would be again a modified hexagonal for both the wing and the tail section airfoils.
Even the destabilizers on the front fit nearly perfectly the (General) hexagonal shape outlined.
Generally this is what we would call “implied”. How do you control a plane? It isn’t exactly drag that causes the plane to steer when trim devices, elevons, ailerons, rudders, etc are deflected. In the case of the missile the only difference is that none of these surfaces produce any usable lift until angle of attack is involved.
The same airfoils pictured side-by-side:
That is your assumption.
They are not there to provide lift. Only to control steering of the missile.
At the speeds the missile flies the sharp edges on the control fins prevent the formation of a detached bow shock.
You are the only person that says they are wings. Not even your own sources state this.
You do not know the definition of the word imply is either.
It’s not implied. Its directly stating they are for control. Please get an education.
Again, you are the only person that says they are wings. Not even your own sources state this.
Not even your sources on the Old Forum state this either.
Correct, that is the case for both the wings at the rear and the movable wings in the middle… not to mention the destabilizers at the front. It’s a missile. Slicing through air is what it is intended to do.
They quite literally state this.
If I state that trim devices are used to control an object designed to fly through the air what force do you suspect it uses to do so? Air pressure?
According to Rosoboronexport (State export company of air-to-air missiles for Russia)
It states clearly “rotary wing” when discussing these parts together, or as a “rudder” when discussed individually for the movable wings in the mid section.
You cannot fathom that translation errors occur when documentation is translated literally online. The shape and design of these “control fins” speak for themselves;
You can repost the same massive pictures 400 times & highlight them all the colors of the rainbow.
It makes no difference.
You do not know what flight control surfaces are. They do not produce enough airflow deflection or air pressure change to be considered lift & are used only to control the aircraft/missile’s direction in 3 dimensions.
This all comes down your lack of education of what Lift is. This is taught to us in the 4th grade which you still cannot comprehend.
The R27 Patent does not whatsoever call them wings. They call them control wheels & even referred to as rudders.
Because rudders control steering.
The R27 patent supersedes what any export company calls them.
I mean the very slight differences in air pressure due to the air above the fin being subject to less vertical atmospheric pressure than the air below the fin.
Edit: Idk what the argument is at the moment, I’m just wondering if that small pressure differential is negligible in general or not.
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