Jay481985 Posted November 14, 2006 Share Posted November 14, 2006 ( the tires explode due to the high forces involved, setting the aircraft on fire, which then crashes and burns like the Concord did. That was a sad situation where something on the ground punctured the tires in which it was sucked into the turbojet. Also some fun tibets of airplanes: The tires are filled with nitrogen. The braking system was first to have used ceramic brakes prior to race cars and now some expensive sports cars. Also if a 747 were to land I believe 2-3 times within an hour, the wheels would explode due to the vast amount of heat. Quote Link to comment Share on other sites More sharing options...
Macho Nacho Posted November 14, 2006 Share Posted November 14, 2006 Ok it will take off, but the real question is will it be on time and will they loose my luggage? Quote Link to comment Share on other sites More sharing options...
rplace Posted November 14, 2006 Share Posted November 14, 2006 Was this too much to read through? No, it was perfect! I have been trying to convince some people I work with that it will fly but can't make them see it. You did an excellent job. I will surely pawn your work off as mine [] Nice Job! BTW, Ray's take was an interesting and good one too. Quote Link to comment Share on other sites More sharing options...
Andy W Posted November 14, 2006 Share Posted November 14, 2006 [Joe Pesci]OK, OK, OK, OK[/Joe Pesci] Lets imagine that the conveyor is really really really big, and the conveyor is moving 1,000 miles per hour in the direction opposite that the plane is pointing, and the plane is moving with the conveyor - backward to an obsever standing on a motionless obect hovering above this huge conveyor. The conveyor is so big it has its own gravity and pulls the air along with it. The pilot starts the engine and attempts to take off. Can the plane take off? The earth itself is that conveyor, folks! If you think that the plane in the original question can't take off, then planes would only be able to take off when they are facing EAST! The ground at the equator of the earth is moving ~1,000 mph to the east. In fact, most planes in the northern hemisphere take off facing WEST (prevailing winds). I am not saying you are wrong but isn't the plane and earth rotating at the same time so the relative speed = 0? To an observer standing on the runway, the plane is not moving. To an observer floating in space the plane is moving at the speed of the rotation of the earth. A plane heading west on a runway at the equator (with the earth is spinning east at 1,000mph), and assuming that the plane needs to be going 200mph to lift off, to an observer in space, the plane will be going 800mph BACKWARDS when it takes off. As said by those in both camps, the only thing that matters is the speed of the plane relative to the air. Quote Link to comment Share on other sites More sharing options...
PhilMays Posted November 14, 2006 Share Posted November 14, 2006 [Joe Pesci]OK, OK, OK, OK[/Joe Pesci] Lets imagine that the conveyor is really really really big, and the conveyor is moving 1,000 miles per hour in the direction opposite that the plane is pointing, and the plane is moving with the conveyor - backward to an obsever standing on a motionless obect hovering above this huge conveyor. The conveyor is so big it has its own gravity and pulls the air along with it. The pilot starts the engine and attempts to take off. Can the plane take off? The earth itself is that conveyor, folks! If you think that the plane in the original question can't take off, then planes would only be able to take off when they are facing EAST! The ground at the equator of the earth is moving ~1,000 mph to the east. In fact, most planes in the northern hemisphere take off facing WEST (prevailing winds). That's all it took. I get it now. The earth is a big conveyor! Very nicely explained. Sometimes an explanation can be so complicated that I loose it pretty quickly. Nicely done. And by the way, I did not waste my time in college. Let's see...frat parties, booze, women...a guy has to have his priorities ya know! OK the damn plane will fly, where are we going? Quote Link to comment Share on other sites More sharing options...
oldenough Posted November 14, 2006 Share Posted November 14, 2006 Well Good mornin', must admit i was suprised to see that this baby has'nt been put to bed yet. Surely out of all the members on this forum, and the diversity of occupations we have, theres gotta be a pilot or two out there. Or maybe there just looking in with total dis-belief rolling around laughing in their g-suits. Hey but having said that if an Admiral can't get it right.....Well!!! Quote Link to comment Share on other sites More sharing options...
JetJockey Posted November 14, 2006 Share Posted November 14, 2006 The wing or airfoil has to be going fast enough (airspeed over and under the wing) Bournoulis theorem, to offset and be more than the weight of the aircraft. Lift must exceed weight Thrust must exceed drag. For once a topic I actually do know something about! Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted November 14, 2006 Share Posted November 14, 2006 [Joe Pesci]OK, OK, OK, OK[/Joe Pesci] Lets imagine that the conveyor is really really really big, and the conveyor is moving 1,000 miles per hour in the direction opposite that the plane is pointing, and the plane is moving with the conveyor - backward to an obsever standing on a motionless obect hovering above this huge conveyor. The conveyor is so big it has its own gravity and pulls the air along with it. The pilot starts the engine and attempts to take off. Can the plane take off? The earth itself is that conveyor, folks! If you think that the plane in the original question can't take off, then planes would only be able to take off when they are facing EAST! The ground at the equator of the earth is moving ~1,000 mph to the east. In fact, most planes in the northern hemisphere take off facing WEST (prevailing winds). I am not saying you are wrong but isn't the plane and earth rotating at the same time so the relative speed = 0? To an observer standing on the runway, the plane is not moving. To an observer floating in space the plane is moving at the speed of the rotation of the earth. A plane heading west on a runway at the equator (with the earth is spinning east at 1,000mph), and assuming that the plane needs to be going 200mph to lift off, to an observer in space, the plane will be going 800mph BACKWARDS when it takes off. As said by those in both camps, the only thing that matters is the speed of the plane relative to the air. well since the earth and person are moving at the same time yes, the person from space will see it that way, as is always, everything is relavent. Quote Link to comment Share on other sites More sharing options...
sheltie dave Posted November 14, 2006 Share Posted November 14, 2006 If you consider the conveyor to be the Earth(an infinite size compared to the plane), it will fly. The plane will have a positive or negative displacement vector no matter how it takes off. If you consider the conveyor to be finite, and the plane has a zero displacement vector from the ground(the model the admiral stated,) then the plane most definitely will not take off. The constraints must be defined to determine a correct answer. Have the same question and place it at the space station. A vacuum will not support gas or diesel combustion. It won't fly. Quote Link to comment Share on other sites More sharing options...
sputnik Posted November 14, 2006 Share Posted November 14, 2006 ......If you consider the conveyor to be finite, and the plane has a zero displacement vector from the ground(the model the admiral stated,) then the plane most definitely will not take off. I would love to hear the explanation for your (and the admiral's) conclusion. Why is there a "zero displacement vector"? How is the force from the conveyor transmitted to the plane?Feel free to use math and physics. Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted November 14, 2006 Share Posted November 14, 2006 I think this is completely relavant. Quote Link to comment Share on other sites More sharing options...
sheltie dave Posted November 14, 2006 Share Posted November 14, 2006 Sputnik, you are standing on the ground. The nose of the plane is on the fifty yard line of a hundred yard long football field. The football field actually is a freewheeling conveyor belt, one like UPS uses. The plane fires up, and the brakes are released. Whatever speed the plane would normally go down the football field is transferred to the freewheeling conveyor, closing the loop on an equal and opposite reaction to the initial force. The nose of the plane will never advance beyond the 50 yard line, hence there is no displacement vector in this example, and thus the plane will not get off the ground. In this model the admiral is correct. Other models obviously lead to other results. It all depends on the paradigms of the model you use. Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted November 14, 2006 Share Posted November 14, 2006 "Whatever speed the plane would normally go down the football field is transferred to the freewheeling conveyor..." ??? The plane is acting upon the *AIR* by using props to accelerate the air rearward, or jet engines to exhaust combustion products out the back of the chamber, producing a thrust vector in the opposite direction, neither of which has *ANYTHING AT ALL* to do with the motion of the football field. It can be going frontwards, sideways or backwards for all the plane cares (providing the proper gimbals are in the wheels in the event of the sideways motion) - the plane only cares about its velocity relative to the air mass in which it is embedded, an air mass unaffected by the motion of the ground below it. Come on, people. Fire up a few neurons. This is really getting depressing. Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted November 14, 2006 Share Posted November 14, 2006 What would happen if I where wearing roller skates standing on a tread mill going full tilt with a GE F110 jet engine strapped to my back, that would produce any where between 27,000 to 32,000 lbs of thrust? Would I fly? Now mind you that tread mill is going full speed. Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted November 14, 2006 Share Posted November 14, 2006 JetJockey, Planes fly because the wing pushes the air down. Read Stick and Rudder. If the Bernoulli principle were responsible for aircraft flying, they couldn't fly inverted, could they? Bernoulli's effects reduce drag and add some minor amount of lift (under certain conditions) but the angle of attack of the wing diverting the airmass downward is what results in the force vector supporting the weight of the aircraft. Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted November 14, 2006 Share Posted November 14, 2006 "What would happen if I where wearing roller skates standing on a tread mill going full tilt with a GE F110 jet engine strapped to my back..." You'd set your a$$ on fire and appear on America's Funniest Home Videos, thus ensuring fame and fortune beyond your wildest dreams. Quote Link to comment Share on other sites More sharing options...
oldenough Posted November 14, 2006 Share Posted November 14, 2006 Ray Garrison wrote: Planes fly because the wing pushes the air down. Read Stick and Rudder. That might possibly be true, but my understanding as a layman is that a wing generates lift by it's shape having the ability to move air faster over its top surface, this in turn produces an area of low pressure therefore producing lift. Yes you can produce lift in other ways (angle of attack) but the trade off is drag, something that you most certainly can do without. Come back Jet Jockey being an airline pilot puts you in a better position to explain this....John Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted November 14, 2006 Share Posted November 14, 2006 If you consider the conveyor to be the Earth(an infinite size compared to the plane), it will fly. The plane will have a positive or negative displacement vector no matter how it takes off. If you consider the conveyor to be finite, and the plane has a zero displacement vector from the ground(the model the admiral stated,) then the plane most definitely will not take off. The constraints must be defined to determine a correct answer. Have the same question and place it at the space station. A vacuum will not support gas or diesel combustion. It won't fly. not if you add oxygen to the mixture! or an oxidizer of some kind Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted November 14, 2006 Share Posted November 14, 2006 JetJockey, Planes fly because the wing pushes the air down. Read Stick and Rudder. If the Bernoulli principle were responsible for aircraft flying, they couldn't fly inverted, could they? Bernoulli's effects reduce drag and add some minor amount of lift (under certain conditions) but the angle of attack of the wing diverting the airmass downward is what results in the force vector supporting the weight of the aircraft. most do not "fly upsidedown" or do so very seldomly...... Mind you are we talking about military crafts or jetliners..... There is a big distinction as many military planes can use the angle of attack as the military plane is strong enough, try to do a 5 g sustained on a jetliner and you will set off every alarm telling you that the plane will break apart. Not being political or anything but the 9/11 terrorists put the planes in such strain while on the last part that the plane most likely if they missed would have broken apart. Quote Link to comment Share on other sites More sharing options...
sputnik Posted November 15, 2006 Share Posted November 15, 2006 What would happen if I where wearing roller skates standing on a tread mill going full tilt with a GE F110 jet engine strapped to my back, that would produce any where between 27,000 to 32,000 lbs of thrust? Would I fly? Now mind you that tread mill is going full speed. I saw Wyle E. Coyote try that in a Road Runner cartoon...........It didn't turn out well. Quote Link to comment Share on other sites More sharing options...
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