It is a primary source as TsAGI did the aerodynamic design alongside Sukhoi for the Flanker.
Sukhoi Su-27/30/33/35/37 Flanker series & Su-34 Fullback - History, Design, Performance & Dissection
TsAGI did the aerodynamic design, Sukhoi adapted it (the conceptual design / theory) for a production vehicle later. Either way, the primary design institute behind the Su-27 and MiG-29 series.
We know MiG had to increase stability margin so they could get away with a simpler flight control system and reduce cost.
In other words document from Amazon will be worse from the same document from other souruce ?
Ps. It’s any TsAGI publication index ?? (Not in Russian language or at least translated)
I would argue that this would constitute your source as primary given the work TsAGI put into the Flanker.
The source MiG-23 provided was authored by the director of TsAGI under the title: High Maneuverability, Theory and Practice - G.I. Zagainov
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It was published here originally;
Whaaaat?
Static instability is the difference between the Center of mass and the point of aerodynamic focus, if it is positive then the aircraft is not stable
First thing:
Su-27 is tailed delta plane. Delta wing has an interesting property - the center of gravity of the wing changes in different speed ranges and AoA
Second:
Plane is full with fluid oils fuel etc. Center of gravity is not constant. And may vary depending from various reasons.
That’s why we have static stability and dynamic stability. Usually static stability not include weight of fluids or weapons.
For example P39 depending of ammunition weight and fuel can be unstable. That not change fact the design was stable
The “lift body” feature refers to the aircraft fuselage design that generates additional lift. In the case of fourth-generation fighter jets, such a solution can enhance aerodynamics and maneuverability, enabling better performance in air combat
There is a spanish Su-27 manual? lmao I want it
Few years ago in different game forum was used as source in dissuasion like this.
It’s was probably fake one…
I have manual Su 27SK in Russian and English.
do you have a link?
From the same ICAS2002 congress presented by Sukhoi, they said the T-10 has a longitudinal instability margin of 3% to 5% of mean aerodynamic chord. This is even less stable than the production aircraft.
So what kind of a Su-27 iteration it is that is stable at first?
Su 27 has a relaxed stability depending on the aircraft centre of gravity determined by the fuel. If it has full tanks it is statically stable, if the fuel drops below a certain percentage it becomes less stable. It’s simple, with a full forward tank the aircraft’s centre of gravity is more forward. As the fuel is used up, the center of gravity shifts to the rear and the plane becomes less stable.
The control system will ensure the aircraft is controllable to -5% beyond the neutral point ( that doesn’t mean the Su 27 will get there, I don’t know of course).
Why are all of you bothering with this ?
Whaat???
But as I wrote earlier, in almost the entire range of fueling, the Su-27 is not stable
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It will be stable at supersonic speeds, as well as at subsonic speeds with full fuel.
I think Sukhoi mentions static margin with the designed center of gravity in mind, and also the neutral point and aerodynamic center at low AOA and subsonic speeds. Otherwise the figure can be so dynamic.
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at supersonic speeds, all aircraft are stable.
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