BBS: TELESC.NET.BR Assunto: Re: Conveyer belt question De: Rug Rat Data: Thu, 26 Feb 2026 14:47:59 +0000 ----------------------------------------------------------- You are still in box created by the comparing it to a car. The wheels on an airplane have nothing to do with propelling the aircraft forward. The motive force (Thrust) is provided by a completely seperate sorce (Propeller or jet). The wheels just freespin (Or are just along for the ride). Since they don't provide the force pushing it forward the belt is not acting against this force. Aircraft moves forward and will reach takeoff speed. If you want to compare it to the car, since this is what hangs people up. Let's do this experiement with the car. Belt matches motive force caused by engine transfering power to the wheels and friction on between the tires and treadmill cancel each other out, car does not move... With out changing anything. Acelleration force on the car or treadmill speed (Or those metal rollers on a speedometer calibration or smog check station). Now get behind the car and push it.. What happens? The car will move, because you are applying a second force which will become additive to 2 other forces in opposition to each other. Lets assign this an arbitrary value of 2. so say car moving forward is 60 treadmill is 60 60-60=0+2=2. You have a net positive force of 2. Airplane. Wheels have ZERO motive force, but we will still assign them a speed value (You will see why in a second..) SO everyting is at idle. treadmill is not moving, engine isn't providing thrust, tires are not spinning. So we apply thrust so that number will go up exponentionally. Tread mill and tires match their speed. increasing exponentionally, Your Cesna lets say has a Vr of 80kts. WHEELS 80 - Treadmill 80 = 0. However we are not done... Becaue like you pushing the car from behind with have the thrust value for the propeller of +80 0+80 still = 80 and you will take off. (That is the visual demonstration), because in the real world the wheel rotational speed would be twice as fast. The aircraft will take off. If STILL won't listen. There are plenty of Youtube videos on it. https://www.youtube.com/results?search_query=airplane+treadmill+mythbusters Rug Rat (Brent Hendricks) Blog and Forums - www.catracing.org IMAGE BBS! 3.0 - bbs.catracing.org 6400 C-Net Amiga BBS - bbs.catracing.org 6840 --- CNet/5 * Origin: The Rat's Den BBS (1:135/250) ----------------------------------------------------------- [Voltar]