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About Boris-Barboris

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    I'll be right happy to

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  1. J-20 Fighter stable or unstable canard airframe?

    Problem of delta wing itself. On different designs: i'm pretty sure the balancing itself is the same for all modern fighters - as close to neutral as possible, but preferably stable. Every big player is already experienced enough to build reliable control systems. Wing plan however is closely related to tradition, existing industry and tactical requirements, imo. Yeah, looks like we just speak in different terms.
  2. J-20 Fighter stable or unstable canard airframe?

    You can perfectly make a flip-happy stable airframe. Faster to reach certain AoA? Yes. To reach and not exceed it? No, not really. Why would unstable airframe be less draggy than a stable one? Why would making an airframe unstable increase authority of it's control surfaces? Yes, but if you make that strong correcting moment very weak, you make abovementioned "advantages" of unstable design moot, while still being stable. Just because the craft is hard or impossible to fly manually doesn't mean it's unstable. If your airframe takes 1000 years to return back to prograde after small AoA perturbation, it's still stable. That's the only point I can stand besides. And it always implies, that the designers just coudn't find a stable way. I do not state that there was a stable way for each of those cases (let's assume F-16 is actually statically unstable when subsonic, though the sources are mostly unofficial), but I also doubt anyone can prove that there wasn't. Neutral airframe does all of this better. Not really, I just need to find someone who will point me to the exact research paper.
  3. J-20 Fighter stable or unstable canard airframe?

    Let's go on with this one, it's good enough for static. In all my posts above, and in this post, when I say stable\unstable\neutral, I mean it's static flavor. Now hear out my point: There is no reason to intentionally make airframe statically unstable for the sake of it. There may be airplanes out there that are st.unstable, but I do believe their designers would gladly make them neutral if they could. For example, I did read unofficial reports of people saying F-16 being st.unstable on subsonic, because they were forced to do it to keep supersonic performance in certain margin. If they could find the way to keep supersonic performance at bay while making subsonic phase neutral, the plane would perform generally better. Instability is a necessity, not a goal, because it brings larger risk with it and bears no reward in itself. Unstable craft is not more maneuverable than a neutral one. It has worse sustained turn rate. It has the same or worse aiming time (let's say you fly with stable pitch 0 and need to have stable pitch 10 deg. as soon as possible). It's even more risky than a neutral one. The only thing it can actually do better is to flip as fast as possible, and the place for such maneuver in modern doctrines is hard to be seen. This maneuver tears the plane to pieces or kills the pilot on high speeds, and on low speeds TVC is, imo, much more important.
  4. J-20 Fighter stable or unstable canard airframe?

    Define unstable and maneuverable please, so we can discuss things on common ground.
  5. J-20 Fighter stable or unstable canard airframe?

    The only reason I can think of is trans\supersonic shenanigans, in case designers have to optimise the regime (maybe to compensate for mach tuck, idk) so hard they are forced to make the design unstable on other regimes, but I have a feeling this problem was solved without making such drastic sacrifices.
  6. J-20 Fighter stable or unstable canard airframe?

    note the difference When you cross the point where you become statically unstable, there is nothing more to gain. Statically neutral airframe has the best L/D among it's slightly altered towards stable\unstable configuration siblings.
  7. J-20 Fighter stable or unstable canard airframe?

    There is nothing to gain from doing so, therefore I doubt that is the case. "inherently unstable" sounds like a buzzword.
  8. Что еще за фильтр имен? всё оказалось довольно банально, большинство термов в фильтре - просто некорректные грамматические конструкции
  9. Kerbal Space Program 1.3.1 is live!

    Such a horrible tease to proclaim the problem fixed without faulty examples. Does anyone have a bug report or some other leads? upd: [snip] A rather liberal filter, to say the least.
  10. [1.3] CorrectCoL - Stock Aerodynamics Design Aid Continued

    It is not easy to calculate one, and sometimes it does not exist.
  11. I saw your avatar and title and I near burst out laughing. Wow.

  12. Official FAR Craft Repository

    If anyone has the same problem: no, FBW does not do this. There is a "level snap" that snaps wings to level when your roll is very small, like a degree or so, but nothing more. Usual suspect: FAR wing leveler you somehow activated previously.
  13. Aircraft woes. Control issues.

    Stock aero has no stall per se. edit: it's not rapid, surfaces just smoothly loose lift with increased AoA. Not fast enough to make your canard weak and kick the plane back to prograde.