Rob Posted February 7, 2008 Share Posted February 7, 2008 How can you tell the difference between the jet engine and the power being put through the rear wheels? In a fully controlled environment you can't, as the body that is excerting the force is still the same body. Because the Jet is not acting against the rollers, it is against against the air. Therefore if you put a jet car on rollers, the car WILL move forward off the rollers. The jet engine is held in the car body, and its weight is transferred to the ground through the wheels, but that is a vertical force, and all the horizontal force pushes the air Quote Link to comment Share on other sites More sharing options...
JustGav Posted February 7, 2008 Share Posted February 7, 2008 This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction). I've now read this again and again and discussed with friends, the flaw in all of this is the wording. The conveyer has control system that tracks the plane speed, it doesn't specify that it measures wheel speed. As such any forward motion be it rotary through the wheels in the case of a car, or thrust in the case of a plane will be counteracted by the belt. The big HOWEVER is, it all depends on the plane type.. if the engines can pull sufficient air over the wings it may be possible to create lift in the same way a helicopter generates lift. Turbo prop engines perhaps... Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 7, 2008 Share Posted February 7, 2008 Because the Jet is not acting against the rollers, it is against against the air. Therefore if you put a jet car on rollers, the car WILL move forward off the rollers. The jet engine is held in the car body, and its weight is transferred to the ground through the wheels, but that is a vertical force, and all the horizontal force pushes the air Yes but you've only explained why jet motors are more powerful, not proven me wrong. Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 7, 2008 Share Posted February 7, 2008 I've now read this again and again and discussed with friends, the flaw in all of this is the wording. The conveyer has control system that tracks the plane speed, it doesn't specify that it measures wheel speed. As such any forward motion being it rotary through the wheels in the case of a car, or thrust in the case of a plane will be counteracted by the belt. The big HOWEVER is, it all depends on the plane type.. if the engines can pull sufficient air over the wings it may be possible to create lift in the same way a helicopter generates lift. Best post so far. In these circumstances, although I don't like it, we'll have to agree to disagree. Quote Link to comment Share on other sites More sharing options...
Rob Posted February 7, 2008 Share Posted February 7, 2008 Where does this idea come from that the propeller blows air over the wings? The propellor drags the body of the plane through the air and the air passing over the wings creates lift. Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 7, 2008 Share Posted February 7, 2008 Where does this idea come from that the propeller blows air over the wings? The propellor drags the body of the plane through the air and the air passing over the wings creates lift. But with my model/idea the plane doesn't move anyway so no lift. Quote Link to comment Share on other sites More sharing options...
JustGav Posted February 7, 2008 Share Posted February 7, 2008 Where does this idea come from that the propeller blows air over the wings? The propellor drags the body of the plane through the air and the air passing over the wings creates lift. I know that... however I am no expert aircraft person, and wondered if it is all possible for a propeller driven plane to push enough air over the wings? Was just a general question... Can they or can't they? Quote Link to comment Share on other sites More sharing options...
JustGav Posted February 7, 2008 Share Posted February 7, 2008 Best post so far. In these circumstances, although I don't like it, we'll have to agree to disagree. But with my model/idea the plane doesn't move anyway so no lift. Hmmm, given my intepretation of it, I do in fact agree with you...it won't take off (unless powered by some silly engine that can theoritically move sufficient air to provide lift) Quote Link to comment Share on other sites More sharing options...
Rob Posted February 7, 2008 Share Posted February 7, 2008 Yes but you've only explained why jet motors are more powerful, not proven me wrong. No, it doesn't matter about the power of the jet, it's the way it delivers the power. Lets say the jet has only 200bhp, or whatever that is in lbs of thrust. It's certainly enough to move the body of a supra. The car moves because the thrust from the jet pushes against the air, not against the surface of the earth or the rear wall of the building, it pushes the air and that equal and opposite force drives the car body/jet forward. This is why seaplanes work, if your argument were correct, seaplanes coould not take off because the water that bears their weight would not be stable enough to take the force applied to it. it would swirl around the the seaplane would remain stationary. But seaplanes DO take off because the propellors push the air, not the water, in the same way that jetboats push the water, not the air, and hovercrafts push the air, not the water. Quote Link to comment Share on other sites More sharing options...
johnnyknox Posted February 7, 2008 Share Posted February 7, 2008 But with my model/idea the plane doesn't move anyway so no lift. how does your model work? How can the conveyor belt be acting against the thrust produced by the engines on the plane? Quote Link to comment Share on other sites More sharing options...
Rob Posted February 7, 2008 Share Posted February 7, 2008 same way a helicopter generates lift. ... Hang on, don't assume that a helicopter takes off because it blows air down against the ground, it takes off because its wings are moving through air, generating negative pressure on the top side of each blade sucking it up into the sky. Quote Link to comment Share on other sites More sharing options...
Pixelfill Posted February 7, 2008 Share Posted February 7, 2008 I'm just glad that the Ralphster didn't post a public poll, because I misread the question, and picked the wrong answer. because it wasn't a public poll nobody will know what answer I put, so I won't look stupid. Mike Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 7, 2008 Share Posted February 7, 2008 No, it doesn't matter about the power of the jet, it's the way it delivers the power. Lets say the jet has only 200bhp, or whatever that is in lbs of thrust. It's certainly enough to move the body of a supra. The car moves because the thrust from the jet pushes against the air, not against the surface of the earth or the rear wall of the building, it pushes the air and that equal and opposite force drives the car body/jet forward. This is why seaplanes work, if your argument were correct, seaplanes coould not take off because the water that bears their weight would not be stable enough to take the force applied to it. it would swirl around the the seaplane would remain stationary. But seaplanes DO take off because the propellors push the air, not the water, in the same way that jetboats push the water, not the air, and hovercrafts push the air, not the water. Seaplanes work because the air displaced by the engine/prop creates forward thrust against the water. This means that the plane moves forward, because it is moving against the medium it's pushing against. You're situation won't work because at the end of the day we are talking about an object creating power against another object. Be it the atoms in air or the rollers of a rolling road the principles are the same. End of the day, every action has an equal and opposite reaction. It doesn't matter how big the object or how small the force, if one thing is pushing one way and one thing pushing another way then your object won't move. Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 7, 2008 Share Posted February 7, 2008 how does your model work? How can the conveyor belt be acting against the thrust produced by the engines on the plane? Because thats how the hypothetical situation is posed. Read the 1st post again. Quote Link to comment Share on other sites More sharing options...
JustGav Posted February 7, 2008 Share Posted February 7, 2008 The burst into flames, is correct answer, it has to be and here is why... Lets assume stage 0. Plane is not moving and there is no force excerting acceleration, therefore the belt does not move. Agreed? Next bit. The engine is powered up, and provides x amount of thrust, resulting in an accelerating force upon the aircraft. Due to the engine pulling the aircraft forward by your own admission as above, the aircraft will begin to move forward, however in this example we have specificied that the conveyer belt will match plane speed. Therefore the quicker the plan attempts to accelerate it will be counteracted by the conveyor belt. This is of course assuming that the conveyor belt is in perfect synchronicity with the plane speed (theoritical) will ensure that the plane will always remain in the same position relative to somebody outside the test scenario. Every reaction of the plane will be matched with an equal reaction of the belt system. Since the plane does not move forward and assuming no other forces acting upon the plan, it will not experience any airflow over the wings (using the previous statement that the engines pull the plane's body). Therefore the pilot will turn up the power of engines and be counteracted, turn them up, they will get hot because of no air flow and CABOOOM In a real world example the above is not applicable as external variables will affect the outcome. Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 7, 2008 Share Posted February 7, 2008 Hang on, don't assume that a helicopter takes off because it blows air down against the ground, it takes off because its wings are moving through air, generating negative pressure on the top side of each blade sucking it up into the sky. Which can't happen in this situation because the plane won't go anywhere. Quote Link to comment Share on other sites More sharing options...
Rob Posted February 7, 2008 Share Posted February 7, 2008 End of the day, every action has an equal and opposite reaction. It doesn't matter how big the object or how small the force, if one thing is pushing one way and one thing pushing another way then your object won't move. Well sir, you are plainly wrong, since what you have just described would therefore mean that all motion is impossible. Quote Link to comment Share on other sites More sharing options...
JustGav Posted February 7, 2008 Share Posted February 7, 2008 Well sir, you are plainly wrong, since what you have just described would therefore mean that all motion is impossible. Dude.... For every action there is an equal and opposite reaction is a scientific FACT, proven MANY times overs with hard facts. Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 7, 2008 Share Posted February 7, 2008 Well sir, you are plainly wrong, since what you have just described would therefore mean that all motion is impossible. No. I'm saying that there are forces moving the other way, not that all force is equal to every other force. How can someone walk down a moving runway if the runway moves at the speed they walk? Jet engine or not, thats impossible. Quote Link to comment Share on other sites More sharing options...
johnnyknox Posted February 7, 2008 Share Posted February 7, 2008 Because thats how the hypothetical situation is posed. Read the 1st post again. Granted...wording is not great But you put a plane on a giant sized treadmill...what part of the plane is in contact with the treadmill? Quote Link to comment Share on other sites More sharing options...
johnnyknox Posted February 7, 2008 Share Posted February 7, 2008 No. I'm saying that there are forces moving the other way, not that all force is equal to every other force. How can someone walk down a moving runway if the runway moves at the speed they walk? Jet engine or not, thats impossible. No..but put that person on rollerskates and strap a rocket to their back...would they move down the runway? Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 7, 2008 Share Posted February 7, 2008 Granted...wording is not great But you put a plane on a giant sized treadmill...what part of the plane is in contact with the treadmill? The wheels. So whatever that plane does, it will be in relation to the wheels. If the plane creates thrust, it will spin the wheels faster. This will mean the runway moves faster, hence the plane won't move. According to this situation. Quote Link to comment Share on other sites More sharing options...
Rob Posted February 7, 2008 Share Posted February 7, 2008 The burst into flames, is correct answer, it has to be and here is why... Lets assume stage 0. Plane is not moving and there is no force excerting acceleration, therefore the belt does not move. Agreed? Next bit. The engine is powered up, and provides x amount of thrust, resulting in an accelerating force upon the aircraft. Due to the engine pulling the aircraft forward by your own admission as above, the aircraft will begin to move forward, however in this example we have specificied that the conveyer belt will match plane speed. Therefore the quicker the plan attempts to accelerate it will be counteracted by the conveyor belt. This is of course assuming that the conveyor belt is in perfect synchronicity with the plane speed (theoritical) will ensure that the plane will always remain in the same position relative to somebody outside the test scenario. Every reaction of the plane will be matched with an equal reaction of the belt system. Since the plane does not move forward and assuming no other forces acting upon the plan, it will not experience any airflow over the wings (using the previous statement that the engines pull the plane's body). Therefore the pilot will turn up the power of engines and be counteracted, turn them up, they will get hot because of no air flow and CABOOOM In a real world example the above is not applicable as external variables will affect the outcome. No, I keep stating it, and other have all through this thread. The action being exerted by the planes engine has no reaction from the belt, they are not related or connected in any way. The belt moves under its own power to match the spinning of the wheels. The plane moves forward because its action/reaction is with the air. the wheels spin faster and faster but the plane always moves forward in relation to the air, and to the stationary ground either side of the belt. Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 7, 2008 Share Posted February 7, 2008 No..but put that person on rollerskates and strap a rocket to their back...would they move down the runway? No. Because the runway has already reacted and compenstated for the speed. Quote Link to comment Share on other sites More sharing options...
Rob Posted February 7, 2008 Share Posted February 7, 2008 No. Because the runway has already reacted and compenstated for the speed. No, the runway "reacting" is a misnomer, it "reacts" in that it tries to match the reverse speed, which makes the wheels spin twice as fast, but it does not react against the thrust from the jet pack. Quote Link to comment Share on other sites More sharing options...
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