It's really simple, your WRONG. I think people keep posting just to piss people off. If "the plane wont move", how does a pontoon or ski plane take off? THEY DONT EVEN HAVE WHEELS. I suppose when the plane wants to descend and land, it just engages the wheel brakes? The plane will fly and the wheels will be moving as fast as they usually do, plus the speed of the conveyor. It will take off as the propeller pulls it into lift off. I suppose if you are saying the plane cant take off on a moving runway, it couldnt land on a moving runway either. If it did, it would come to an instant stop where it couldnt take off from in the first place. I guess the whole concept of landing on an aircraft carrier would be out the door with this.
Actually - this was my very first thought when the thread first came to be. But, then I thought... "Ah, the ol' Vacuum Propeller trick, aye?" http://en.wikipedia.org/wiki/User:West_London_Dweller/Vacuum_propeller
Don't be so sure, as I don't think you have seriously studied the original question. How can the wheels be moving at any given speed, PlUS the speed of the conveyor, if the conveyor is to MATCH the speed of the wheels? You have just violated a requirement of the original question. It is pretty obvious to most people that the relative motion of the runway to the plane is irrelevant. A plane flies because of the wings relative motion to the air, not the landing gears relative motion to the runway (or water, or ice or whatever the plane is sitting on). However, that is not where the problem with the original question arises. Re-read this part of the original question: "The conveyor belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation" Does this mean the conveyor matches the "rotational" or "linear" speed of the wheels? What does "moving in the opposite direction of rotation" really mean? The conveyor surface is generally considered to be moving in a linear fashion, not a "direction of rotation". If the conveyor simply moves along under the plane, matching the planes forward acceleration, then the wheels have no "rotation", so what speed is the conveyor " exactly matching" so as to satisfy the question? This is not a clearly worded question. It introduces contradictory, or unclear requirements. "The plane flies" does not stand as an answer.
It doesnt matter. The implications of the question are clear. Most people think wrongly that a plane cant take off because it is on a conveyor, but it will. I have seen planes take off when they are in storage on a runway here at cessna and a gust of wind picked them up off the ground. They werent moving. They werent running. If you term the question as you say and the conveyor will match the wheel speed, the wheels would be spinning faster and faster until the plane is finally off the ground. The props will provide the wind, pull the plane, and the wheels will turn on the conveyor. When they conveyor catches up, the wheels will spin faster as the plane is still accelerating to takeoff. Its like the feedback in a microphone getting amplified. I have friends that are engineers at cessna, boeing, learjet, raytheon/hawker/beachcraft, and bombarier. They all said it would fly about 5 years ago. I agree with them. http://www.youtube.com/watch?v=0ul_5DtMLhc&feature=related
It won't fly..think about it...Just for a second.. The plane a stationary no matter what amount of throttle you apply.She just won't move. Mythbusters show you can throw into the trash, regarding this one.
"If "the plane wont move", how does a pontoon or ski plane take off? THEY DONT EVEN HAVE WHEELS. I suppose when the plane wants to descend and land, it just engages the wheel brakes?" They don't need wheels, they just need thrust. How do you think a rocket flies? "The plane will fly and the wheels will be moving as fast as they usually do, plus the speed of the conveyor. It will take off as the propeller pulls it into lift off." The OP said nothing about a propeller or even an engine running. "It's really simple, your WRONG.I think people keep posting just to piss people off." Me thinks you've made a fool of yourself! No insult intended.........well, maybe just a little!
Ditto Ditto, put simply the question states: "If the plane is stationary will it take off?" Other questions similar to this one ask: "If the plane is on a moving conveyor will it take off?" Its all in the wording and I think this version has either been written with some thought, or they "got it wrong" - all good fun though.
People who attempt to answer the question fall under 1 of 5 categories: 1) just doesn't get the simple concept of flight and says "No, plane won't fly" 2) gets "it", and thinks anyone who disagrees falls under category 1 3) gets "it", but doesn't think plane flies due to factors like friction and conveyor acceleration 4) truly gets "it" at a fundamental level and discounts friction and other forces 5) actually read the question and realize the flaw in the wording
6) Those that don't answer [like me] and fall into the category of categorizing the answers, like you...shoot, does this count as an answer?...then there is a #7
I changed my original opinion and believe the plane may fly. The conditions stated in the original posting: No wind. Thus no airflow to lift plane. Conveyor is as long and wide as a runway. So the plane has enough room to takeoff. Plane is on the beginning of the belt. Now which side is 'beginning'? With no wind, this should not matter, unless you postion plane so it's 'hanging ten'. But if the plane 'intends to takeoff' it should be facing the full length of the runway. Intends to takeoff. Kind of hard to take off without a means of locomotion. Prop, jet, rubber bands.... Not stated, but the wheels of a plane are not driven. If they were then plane would get to takeoff speed, lift, drop back down after losing speed, lift, drop back down, lift.... So there are 3 possible states the wheels can move. 1) Forward movement, so belt is moving backwards. Depending upon which camp you belong to, it flys or won't fly. Wheel speed, friction, gearing, airflow, laws of physics..... 2) Backward movement, so the belt is moving forward. Backward flying plane???? 3) Zero movement. If the wheels are locked and not rolling, the belt speed is also zero. But if enough thrust is generated, the wheels will skid down the runway/belt until a) pneumatic tires may blow, which may crash the plane. b) solid tires get flatspotted, if it flys apart may crash the plane but if tires survive, or remaining landing gear supports keeps plane semi-straight (lots of sparks and runway/belt repairs) the plane can get enough airflow to cause it to fly. Landing with bad/broken tires...well that's another conundrum. (flame suit on)
= wheels moving at a different "speed" to the belt - so this state is not allowed by the wording of question. = wheels moving at a different "speed" to the belt - so this state is not allowed by the wording of question. = stationary wheels / moving belt - wheels moving at a different "speed" to the belt - so this state is not allowed by the wording of question. I suggest: 4) Zero movement. If the wheels spin, being driven by the belt, at the same "speed" as the belt then the plane stays stationary to the air and hence can generate no lift therefore it won't takeoff. As soon as the pilot applies the external force of thrust from the engines the plane will move and takeoff but will no longer be within the limits of the (flawed) question, hence it cant takeoff whilst staying within those limits. Come on everyone, 100 pages here we come
flawed question: but here goes: WILL NOT FLY. no lift due to differenctial in pressure. basically no movement from the plane or from wind across its wings. that's why on the carrier, we use cats, and make a wind differential by a couple point off the stb. bow. we can launch CODs via just a take-off, dead full throttle off the stern, but if not enought wind [air differential pressure] accross the wings, they'll get CAT'd too. The OP stated NO WIND on the treadmill. and bascially it would be like having the plane on the mill standing still. [now I'll sleep and change my answer tom. but for now correct] Reasons I give is that the question is flawed here: Does not give the wing specs or the treadmill speed, which between the two can determine the lift coeff. IF one stood on a cliff, holding toothpick in each hand outward [wings spread] and now movement or wind how much lift would it take to make you fly [flawed visual right?] now same person, with wings the size of Texas on each arm, outwards, and about the weight of, say, two ozs. then 'perhaps' a slight movement differntial might lift him, but doubt it still. So, the question is flawed.....just can't say either way but the bottom line seems to be NO LIFT. and, to rest anyone's mind: Good thing I gave up my pilot's license....scares the hell out of me at times...that's no way to fly even with a good glide ratio.
That is correct, Sir. And why the plane will not fly. There's a REASON a certain physics board has 4 separate threads on this basic premise, each having a slightly different scenario. Search for: airplane http://www.physforum.com/index.php?showforum=20 On FerrariChat, there is but 1 thread, and it is flawed from the beginning, thereby preventing flight.
