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OK Pilots....got a few questions here....a few things I have always wondered about...

Discussion in 'The Okie Corral' started by ATL Peach Girl, Jun 23, 2004.

  1. ATL Peach Girl

    ATL Peach Girl ♥Meezers♥

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    Excuse my ignorance for a bit........but I have a few questions about big jets and weights and how they work and other things about planes.......

    While sitting at the gate before they push off the thought always hits me "how in the hell can this bird get off the ground with all these people, the fuel and bags crammed into it"??? Yeah I fret about it in my mind...and grip the seat a little at take off......(I don't read or do anything during takeoff....but I sometimes take some pics with my digi cam!!)

    Is the plane on a scale of some sort at the gate and they know how much fuel to pump in according to how much the plane weights when fully loaded and do some math by how far they have to go???? I have a friend who works for AirTran here in Atlanta and he mentioned there being some sort of a balance system???

    It's true, and I have noticed that when my flights are packed we seem to go down the run way LONGER before we lift off.....and earlier if there is less passengers aboard.......(I like 1/2 full flights--but I know the airlines don't!!!!!) One thing I have noticed too is on the Airliners.Net website is that when a plane is heavy the wings are flipped up on the ends slightly.....not so much if the plane is fairly empty.

    And then landings........

    Excuse me while I ask, what exactly goes on....?? I hear those darned engines roar really loud at touch down and it seems the rotors inside turn the opposite way they were going.....am I right??? Reverse thrust??? They thrust out the front to get the plane to slow down and stop??? Funny thing is that I don't fear the landings at all.......but rough touch downs kinda scare me some .......

    I recall a time when I flew in a prop plane from SLC to IDA (Idaho Falls, Idaho) in December. Idaho Falls' run way was crusted ice.....all the way.......as we landed I could see the runway and I was screaming inside myself "why is this %$#@&^%$ runway NOT plowed"????.....I gripped the seat extra hard and prepared for a total skid off the runway.......but we didn't!!! Can someone explain why we didn't??? If you landed a car on such ice it would have been a nightmare for sure!!

    Sorry for such elementary questions. I fly again July 14th and 19th (going to Salt Lake City again).......and having some answers to these questions will help me understand it all more........
     
  2. AK_Stick

    AK_Stick AAAMAD

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    I'm not a pilot but I can answer atleast one thing.


    Peach, when you hear the engines spool up after touch down, they have a cup that closes over the exaust and re-directs the air forward, to use as a brake, the engine itself doesn't spin the other direction, it wouldn't work that way, it would push air away from the combustion chamber.....

    Yes, the plane will take off faster if it has less passengers, there is less total weight. When you figure a plane may haul upwards of 400 people. Thats 200 people who aren't on the plane, figure about 180-200 lbs per man, and about 110-130 for women, thats a lot of weight isnt it? then luggage and all that. Without the weight, the plane can get off the ground much faster.

    The wing tips will be up with a fully loaded plane because the whole wing is acheiving lift, but there is little weight on the very tips of the wings, so they bow up. Maybe a pilot or someone with more knowledge can answer the rest
     

  3. SlimlineGlock

    SlimlineGlock

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    Peach, you must above all remember that pilots value their own lives and if it isn't safe, they aren't gonna go fly.

    The weight and balance system for airliners is straightforward. The airplane weighs a specific amount without fuel or cargo. The weight of the fuel and cargo are also computed so that you know how much the airplane weighs for takeoff.

    Heavy airplanes need long runways to accelerate to a safe flying speed for liftoff. The length of the runway is known, so the maximum weight for that runway can be computed (with safety factors thrown in). Using those figures, the maximum weight for that airplane and runway is used to limit the cargo for your flight so it isn't overweight for a safe takeoff.

    The balance part of the system insures that the weight of the cargo is evenly distributed so that the airplane is not nose or tail heavy.

    The weight of the fuel is important too, because enough fuel to get to your destination plus safety factors must be in the tanks. That can sometimes limit the passengers or cargo if the runway is short.

    There are a lot of folks employed to make sure that this all works out right. Relax and enjoy your flight!
     
  4. Tennessee Slim

    Tennessee Slim Señor Member CLM

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    ATL Peach Girl, all wings flex; it’s just more noticeable with longer wings. And you’re right, they flex more the heavier the A/C is loaded. The wings on the B-52 bomber, for example, flex down so much when full of fuel that the wing tips can droop and touch the ground when parked, so they put an extra landing gear right on the tip of each wing!

    The engines don’t actually reverse direction of rotation when they reverse thrust. With jet engines, there’s some kind of mechanical gizmo (it varies depending on the engine) to redirect the jet exhaust to make the thrust go forward instead of backward. With turboprop A/C, the pitch of the propeller blades can be changed so that they’re pushing forward instead of backward. In both cases, using reverse thrust means a whole lot of additional friction, which is the source of all the extra noise.

    You’re not likely to see it done but jets and turboprops actually can back up on the ground by using reverse thrust. I don’t know of any piston-engined A/C that can reverse thrust.

    And I wouldn’t worry about snow in Salt Lake City in July. ;)
     
  5. Glenairguy

    Glenairguy

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    Aircraft fly because of thrust and a curved wing. The wing creates lift while being pushed because of a principle named Bernoulie (sp).
    The principle actually says that air going over the top curve of the wing goes faster and has less pressure than the air going under the flat bottom of the wing. When you see the moving parts of the wing: slats in the front and flaps on the back, it makes the wing more curved for more lift at slower speeds.

    The pilots have all kind of weight and balance charts for the specific aircraft available, they get a report from the gate officer with a passenger manifest, they have weight of cargo/fuel and know distance that they are going plus reserve fuel needed after landing. The weight of the aircraft determines the configuration, ie. degree of slats and flaps, which determines the speed of lift off and final approach. If the airplane is light, it takes off at a slower speed. If it is heavy, more speed is needed.
     
  6. papasmurf

    papasmurf

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    Well, about the ice on the ground, all I can say is that if there is enough air moving over the control surfaces, you are still flying the aircraft even when it's on the ground, and it will go where you fly it. As to the load problem, wings work by suction on the top, rather than from air striking the bottom. The faster you go, the harder the wings get "sucked up" and the rest of the aircraft with them, so the higher the speed, the more weight it can carry. An irresistable force. But wings bullt for high lift do lose efficiency at higher speeds(more drag). Always in life, we compromise. Modern airliners also have tricks such as leading edge slats that grow the wing size for more lifting ability and spoilers etc. to give them an edge. Pilots in general, I believe, care more about their passengers safety than about their own and might fly a marginally safe aircraft if they where risking only their own life(kind of a thrillseeking bunch, but responsible). This is just what I believe. Jeez, I love planes. Always have, always will.
     
  7. Tennessee Slim

    Tennessee Slim Señor Member CLM

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    I don’t agree. As a pilot, I am obsessed with the safety of the A/C because I know that, if there’s a crash, I’ll be the first to arrive at the scene.
     
  8. M2 Carbine

    M2 Carbine

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    Peach,

    Airplanes fly by magic and helicopters are kept in the air by a determined pilot.;)
     
  9. Tennessee Slim

    Tennessee Slim Señor Member CLM

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    Actually, there are two prevalent theories on the subject:
    1) Since helicopters were invented by a Russian, they fly by means of a commie plot, and
    2) They don't really fly so much as vibrate so hard the earth rejects them.;a
     
  10. FLMarine

    FLMarine

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    Actually helos beat the air into submission. lol
     
  11. Wulfenite

    Wulfenite The King

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    Typically the plane will have enough fuel to fly to its destination, fly to an alternate airport if the destination were weathered in or closed for some reason, and still enough more fuel to stay in the air for another 45 minutes.... AT LEAST. That pretty much the rule for small planes. I wouldent be suprised if the big boys have even more generous safety margins.

    WRT runway lengths. The commercial airliners have "balanced field" requirement. What this means is that they have enough runway that they can accelerate to take off speed and abort the take off and still have enough runway left to stop. This requirement virtually guarantees that there's enough runway even if the craft is badly overloaded.

    You really need to get out on a discovery flight. Talking to flight instructors you find quite a few that have had students that were there to overcome fears about flying. They dont usually go all the way to get their license but they will often go as far as solo. Its kind of hard to be afraid of somthing that you've achieved a level of mastery over. Also as you get into the process you are exposed to how much overkill is built into the airplanes and pilots.
     
  12. F14Scott

    F14Scott Luggage CLM

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    Don't forget what really makes all aircraft fly:

    Lifties!
     
  13. ATL Peach Girl

    ATL Peach Girl ♥Meezers♥

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    I am learning alot guys!!! Great thread!! Thanx for the replies!!

    About getting me in a small plane again for a flight lesson.......ummm......well......I don't like little planes......I was in one twice now and didn't like it one bit.......
     
  14. Wulfenite

    Wulfenite The King

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    I think if you took a lesson you'd find that planes are very similar to guns in that they're a lot less scarry when you're at the controls.
     
  15. M2 Carbine

    M2 Carbine

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    That's OK Peach.
    A little fear of flying is good for your health.


    Years ago I was loading my helicopter for a hundred mile trip offshore.

    One of the passengers came up to me and said, I don't like this sh**.

    I said, What sh** don't you like?

    He said, This riding in these helicopters sh**, it scares me.

    I said, Don't let it worry you. I've got 10,000 hours in this helicopter and this sh** scares me too.

    He got in his car and left.:)
     
  16. Tennessee Slim

    Tennessee Slim Señor Member CLM

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    But not as much as hang gliding. That usta give me the willies worse than skydiving.
     
  17. gamegod86

    gamegod86 Male Lesbian

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    My understanding was that helicopters were actually a "collection of parts flying in close formation."
    .
    .
    .
     
  18. M2 Carbine

    M2 Carbine

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    One of my least favorite ones is,

    Helicopters don't fly,
    it's just that they are so ugly the Earth repels them.;f
     
  19. Dig

    Dig

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    Years ago I was loading my helicopter for a hundred mile trip offshore.

    One of the passengers came up to me and said, I don't like this sh**.

    I said, What sh** don't you like?

    He said, This riding in these helicopters sh**, it scares me.

    I said, Don't let it worry you. I've got 10,000 hours in this helicopter and this sh** scares me too.

    He got in his car and left.


    M2, thats beautiful. spoken like a true helo bubba.
    :)
     
  20. Patriot328

    Patriot328 B756

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    I always thought it was money that made planes fly... :)



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