Aviation thread

Discussion in 'General Chat' started by DIGGS, May 31, 2017.

  1. What are the things under the wing a sticking back. And what are their purpose. I am sure I could Google it easily but I figured I'd ask you.
    20170530_191739.jpg
     
  2. Edit: chemicals to sterilize everyone/mind control.
     
    DIGGS likes this.
  3. That was one of my guesses. Or something to do with the flaps or something.
     
  4. That's my third guess. Its the tank and nozzle assemblies for Chem trail production
     
  5. #6 HippoCrushEverything, May 31, 2017
    Last edited: May 31, 2017
    Mystery tanks
     
  6. fun fact: canadian airplanes use bags of fuel
     
  7. Daphoque you on about?
     
  8. And bags for milk. It's like they have some creepy bag fetish.
     
  9. There's a pretty serious mechanism involved in extending the flaps on the back of the wing for takeoff and landing. Those are just a fairing to hide the flap guides. The purpose of a fairing is just reducing drag, of course, and since the aircraft operates primarily at transonic speeds the fairings are designed around the so-called area rule, giving them a kind of peculiar shape for a fairing (versus say, a fairing found on a car or a low-speed aircraft).
     
  10. Fuel tanks on a commercial aircraft are indeed in the wing and wingbox, but they keep them well away from the leading an trailing edges where a lot of mechanical linkages are found. If they need more fuel space (ie: when a narrow-body jet is converted to private use), they'll shove them in the cargo holds before they'd go anywhere near nacelles.
     

  11. Perfect. I though it may have had something to do with the flaps.
     
  12. Wait, the fuel goes where?
     
  13. In the bags
     
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  14. can someone photoshop a canadian airplane with big testicular bags of fuel hanging off its wings to prove my theory
     
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  15. Fairings to support the flaps. Those things are fucking loud on an a380 btw.



    Every time i hear that sound when i fly on the a380 i get a heartattack
     
    Veyronman likes this.
  16. [​IMG]
     
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  17. vanilla ice
    these rockets dont require fins? is thrust vectoring all that is needed to prevent tumbling or anything weird? from my extensive experience in kerbal space program, fins are required

    about 2:45 separation happens

    why grid fins? why dont we see these in many other applications

    at 6:10 some debris flies by really fast

    landing almost seems like a reverse gif or something, its so graceful

    why dont they use parachutes? or airbrakes? too imprecise letting air grab a hold of the rocket?
    seems like youd be able to save quite a bit of fuel weight
     
  18. Click through the pictures of modern launch vehicles and try to count how many have fins. I think the Chinese Long March is the only one with pronounced fins, and even then it's only on the solid boosters. Most rockets are designed to be inherently stable - a small perturbation in their attitude results in a restoring moment, or a force opposing that disturbance. This allows the rocket to remain stable without any specific control system for that purpose. Fins, by contrast, are heavy, produce a lot of drag, and don't work well at higher altitudes (which can be seconds after liftoff). Most modern rockets use thrust vectoring to determine a specific desired trajectory, as opposed to stability, which ought to be inherent in the system.

    Grid fins stow very compactly against the vehicle they're meant to control, and are actually quite common in applications where the fins have to be deployed as opposed to fixed fins (ie: rockets, bombs, and missiles; folding fin rockets are a notable exception).

    Parachutes have several issues for SpaceX. The biggest being that they have to stages on the return trip: a hypersonic correction burn, and a slow descent burn, plus small corrections. A parachute can shed a lot of velocity cheaply, but they aren't easily steered. SpaceX want to hit a 20 meter target from the edge of space, and so this makes parachutes a bad choice for the high velocity correction. For slow descent, they want to land with nearly zero velocity while parachutes only function with some vertical speed (drag is proportional to v^2), making them difficult to use for the slow descent stage. All in the interim, the grid fins can be used for small corrections on the way down (supersonic and subsonic, transonic they basically coast cause grid fins suck at those speeds).

    I believe I read somewhere (although I can't quickly Google it to confirm) that parachutes would actually be heavier than the extra fuel they need to carry. The rocket is nearly empty, and so they have to throttle down the Merlin engines by a huge amount because they produce a vast amount of thrust relative to these more precision corrections.
     
  19. #20 Vanilla Ice, Jun 5, 2017
    Last edited: Jun 5, 2017
    Also, this isn't the 1960s. Reaction engines and thrust vectoring are incredibly precise.



     
  20. very cool

    thanks
     
  21. Planes amaze me and freak me out at the same time.
     
  22. Same here, i'm afraid of flying yet it's so incredibly interesting and awesome at the same time. It's weird.
     
  23. Another aviation question to Vanilla

    I know airplanes with their modern turbofans can fly on 1 engine just fine and land safely. But for how long? If you are above the ocean at the farthest place from land, can the plane still manage to safely land at an airport? Does flying on 1 engine take considerably more effort?
     
  24. Sometimes I get all tensed up mid-flight, from the scope of whats actually happening. But seeing awesome things out of the window, like islands, or cities, makes me forget about it and feel amazed. Its weird.
    Hate not being next to a window, or taking night flights over the ocean :(
     

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