Mostly_Harmless 0 #1 December 28, 2006 Ok I am in a bit of a debate with this question: A plane is standing on a runway that can move (like a giant conveyor belt). This conveyor has a control system that tracks the plane's speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction). Will the plane be able to take off? I say no since the plane needs speed to get air to flow over it's wings to create lift. The plane would have to travel twice as fast as the conveyor to take off. Opinions?_________________________________________ www.myspace.com/termvelocity Quote Share this post Link to post Share on other sites
piisfish 135 #2 December 28, 2006 QuoteA plane is standing on a runway that can move (like a giant conveyor belt). This conveyor has a control system that tracks the plane's speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction)... The plane would have to travel twice as fast as the conveyor to take off. Opinions?no it won't take off flying, no it can't go double the speed as the conveyor belt matches the speed. Yes it will get airborne whe it reached ludicrous speed and the conveyor belt blows up.scissors beat paper, paper beat rock, rock beat wingsuit - KarlM Quote Share this post Link to post Share on other sites
piisfish 135 #3 December 28, 2006 Oh just thought of another option. Apply full brakes on the plane to fool the conveyor belt tracking system. The system will not counter the speed and the plane will be able to take off.scissors beat paper, paper beat rock, rock beat wingsuit - KarlM Quote Share this post Link to post Share on other sites
ChrisL 2 #4 December 28, 2006 QuoteOk I am in a bit of a debate with this question: A plane is standing on a runway that can move (like a giant conveyor belt). This conveyor has a control system that tracks the plane's speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction). Will the plane be able to take off? __ My mighty steed Quote Share this post Link to post Share on other sites
drudchen 0 #5 December 28, 2006 lol The plane will take off easily The plane's prop pushes from the air creating airspeed. The only thing the speed of the conveyor belt will change is the rotation speed of the wheels, which will be rotating at double the speed comparing to usual ground takeoff. Does this make sense so far? This is all considering no friction on the axis of the wheel, assuming the wheels can rotate freely. If there is some friction, it will slow down the plane a little bit, but the real-life effect will still be minimal. So, yes - plane will take off. A car wouldn't go anywhere as it uses ground to 'push from', but the plane uses air. Now - the more interesting question, if you can create 90mph wind in plane's face, it will be able to take off vertically just like a heli? cool! Quote Share this post Link to post Share on other sites
playgroundguy 0 #6 December 28, 2006 WRONG!Good, Better, Best, never let it rest 'till your good better and your better best Quote Share this post Link to post Share on other sites
labrys 0 #7 December 28, 2006 5 pages of debate on the question here: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?do=post_view_flat;post=2005988;page=1;sb=post_latest_reply;so=ASC;mh=25;Owned by Remi #? Quote Share this post Link to post Share on other sites
freeflir29 0 #8 December 28, 2006 I wish I had this kind of free time. Quote Share this post Link to post Share on other sites
labrys 0 #9 December 28, 2006 QuoteI wish I had this kind of free time. Kind of an odd comment considering that you post stuff here about 30x more often than the OP. Owned by Remi #? Quote Share this post Link to post Share on other sites
SkydiveStMarys 0 #10 December 28, 2006 Damn!!! BobbiA miracle is not defined by an event. A miracle is defined by gratitude. Quote Share this post Link to post Share on other sites
sundevil777 93 #11 December 28, 2006 Quote5 pages of debate on the question here: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?do=post_view_flat;post=2005988;page=1;sb=post_latest_reply;so=ASC;mh=25; The absolutely-positively-bet the ranch on it correct answer is YES, it will be able to fly, the wheels will spin at twice the normal speed, so the plane will have a little extra friction to overcome. The problem statement does NOT say that the conveyor is capable of keeping the plane still relative to the ground.People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
divnswoop 0 #12 December 28, 2006 LOL.....what 32,500 posts is a lot? Planes need airflow....propwash isn't airflow QuoteThis conveyor has a control system that tracks the plane's speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction). Quote Share this post Link to post Share on other sites
sundevil777 93 #13 December 28, 2006 QuoteLOL.....what 32,500 posts is a lot? Planes need airflow....propwash isn't airflow Actually, propwash is airflow, but it doesn't go over much of the wing, so its contribution is minimal. Nothing prevents the aircraft from moving forward relative to the ground. The wheels will just be spinning twice as fast as normal.People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
willard 0 #14 December 28, 2006 Quotelol The plane will take off easily The plane's prop pushes from the air creating airspeed. The only thing the speed of the conveyor belt will change is the rotation speed of the wheels, which will be rotating at double the speed comparing to usual ground takeoff. Does this make sense so far? This is all considering no friction on the axis of the wheel, assuming the wheels can rotate freely. If there is some friction, it will slow down the plane a little bit, but the real-life effect will still be minimal. So, yes - plane will take off. A car wouldn't go anywhere as it uses ground to 'push from', but the plane uses air. Now - the more interesting question, if you can create 90mph wind in plane's face, it will be able to take off vertically just like a heli? cool! What he said. Since the aircraft operates in one medium, air, and on another, the ground, it must overcome the drag imposed by both. The air isn't doing anything out of the ordinary in this scenario, so the prop easily does it's job as always with just a small bit of additional rolling friction to overcome from the wheels which must now roll at twice their normal speed. 90 mph headwind? The plane sure will take off vertically, as long as it is producing enough thrust to fly at 90 mph. Any less and it will fly backwards, any more and it will fly forward. Ever watch an AN-2 land in a 20 knot headwind? The bugger comes down almost vertical. Just remember, the aircraft doesn't care what the ground is doing, only what the air around it is doing. Quote Share this post Link to post Share on other sites
jonstark 8 #15 December 28, 2006 I'm sorry but this has to be about the dumbest debate going when you consider that most if not all of you fly in airplanes on a regular basis! An aircraft flies because the wing is moving thru a fluid -not- because it's wheels are rolling. Apply prop or jet thrust and the a/c WILL start to move forward. The rolling conveyor will not keep the thrust from moving the a/c! The wheels will spin faster than normal but the a/c will accellerate to flying speed and FLY. (if the little wheels don't burn up first) Imagine a wind tunnel which would give the appearance of not flying when the a/c is not in relative motion with the tunnel but it is in fact generating lift and flying within the airstream created by the fan inside the windtunnel. Is that what you can't get your brain wrapped around? jon Quote Share this post Link to post Share on other sites
pilotdave 0 #16 December 28, 2006 I've seen this question a bunch of times, but each time it gets presented a little differently. Gotta define how the speed of the plane is measured... if you're measuring the speed by the rotation of the wheels, it gets a little more complicated. Dave Quote Share this post Link to post Share on other sites
sundevil777 93 #17 December 28, 2006 QuoteI've seen this question a bunch of times, but each time it gets presented a little differently. Gotta define how the speed of the plane is measured... if you're measuring the speed by the rotation of the wheels, it gets a little more complicated. Dave Even if the speed of the plane were measured by a mechanism that is related to the rotation speed of the wheels (as opposed to the speed of the body of the airplane relative to the ground), it still wouldn't change the conclusion.People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
playgroundguy 0 #18 December 28, 2006 I stand corrected, this answer is 100% positively correct. The plane will take off nearly normally.Good, Better, Best, never let it rest 'till your good better and your better best Quote Share this post Link to post Share on other sites
freeflir29 0 #19 December 28, 2006 QuoteKind of an odd comment considering that you post stuff here about 30x more often than the OP. Yes but each one of my posts is well thought out and relative to vitally important topics.........like BOOBIES. Quote Share this post Link to post Share on other sites
TMPattersonJr 0 #20 December 28, 2006 Considering there's no drivetrain connecting the wheels to the engine, and the prop wash or jet blast is all that keeps your ass in the air. Yes it will take off and normally, the only difference being the bearings are going to try to explode from spinning so fast to counter the oppisite moving treadmill. For what most of you were saying is that the tires control how fast you move... the only thrust generated by an airplane is from the prop, or fan, which are driven by the engine or turbine.Blue SkiesBlack DeathFacebook www.PLabsInc.com www.SkydiveDeLand.com www.FlyteSkool.ws Quote Share this post Link to post Share on other sites
playgroundguy 0 #21 December 28, 2006 BOOBIES are infinately more important than anything else in this thread.Good, Better, Best, never let it rest 'till your good better and your better best Quote Share this post Link to post Share on other sites
funks 1 #22 December 28, 2006 QuoteQuoteKind of an odd comment considering that you post stuff here about 30x more often than the OP. Yes but each one of my posts is well thought out and relative to vitally important topics.........like BOOBIES. No. Not really. But you go on thinking that while everyone else continues to laugh at the fact that you actually have 32,000 posts on this website. Life meet freeflir29, freeflir29 meet life. You're not going to shoot me now are you? I was kidding, I really was. Quote Share this post Link to post Share on other sites
labrys 0 #23 December 28, 2006 QuoteYes but each one of my posts is well thought out and relative to vitally important topics.........like BOOBIES. Indeed. Owned by Remi #? Quote Share this post Link to post Share on other sites
