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Riddle time! Airplane vs. conveyor
#31
10-28-2006, 08:49 PM
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Join Date: Feb 2005
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Posts: 13,574
RE: Riddle time! Airplane vs. conveyor
So, let's see if I got this right...
Lets say the aircraft needs 200 knots airspeed, or roughly 175mph, ground (I know, it's off by o.oowhatever... I rounded, OK?). If teh conveyor is matching the planes GROUND speed, in the opposite direction, then the "relative" air speed is somehwere close to 100kts (87.5mph), unless he's heading into teh wind, whch wasn't clearly stated, on way or teh other, in the original foumula.
Anyway, we're talking about a 2-1 ratio of thrust to "relative" air speed, given the fact that the "ground" is moving backwards in equal amounts relative to teh planes forward ground speed...
SOOOOO, 400kts is the speed I believe teh tires will be rotating at, or approximately 345miles/hour...
They'd BURST, and the landing gear would collapse, and something would rupture, and kerosese would go spraying all over teh place, and something would ignite it, and a BIG fireball would happen, and teh news organizations would beat the ambulances to the scene of the crash, and people who ought NOT to be on TV, speaking, WILL be on TV, speaking, and teh FAA would subsuquently make it illegal to have airlines take off while sittiing on a conveyor set to move opposite to teh relative forward motion/ground speed of passenger aircraft...
So, let's NOT do this, OK?
It could only ever end BADLY[&o]
Lets say the aircraft needs 200 knots airspeed, or roughly 175mph, ground (I know, it's off by o.oowhatever... I rounded, OK?). If teh conveyor is matching the planes GROUND speed, in the opposite direction, then the "relative" air speed is somehwere close to 100kts (87.5mph), unless he's heading into teh wind, whch wasn't clearly stated, on way or teh other, in the original foumula.
Anyway, we're talking about a 2-1 ratio of thrust to "relative" air speed, given the fact that the "ground" is moving backwards in equal amounts relative to teh planes forward ground speed...
SOOOOO, 400kts is the speed I believe teh tires will be rotating at, or approximately 345miles/hour...
They'd BURST, and the landing gear would collapse, and something would rupture, and kerosese would go spraying all over teh place, and something would ignite it, and a BIG fireball would happen, and teh news organizations would beat the ambulances to the scene of the crash, and people who ought NOT to be on TV, speaking, WILL be on TV, speaking, and teh FAA would subsuquently make it illegal to have airlines take off while sittiing on a conveyor set to move opposite to teh relative forward motion/ground speed of passenger aircraft...
So, let's NOT do this, OK?
It could only ever end BADLY[&o]
#32
10-28-2006, 11:01 PM
RE: Riddle time! Airplane vs. conveyor
ORIGINAL: karguy427
The airplane WOULD take off. The propulsion of the jet engines emits a force against the air. The plane's wheels are not powered. They would just be spinning a lot faster than normal when the plane hits its take-off speed.
The airplane WOULD take off. The propulsion of the jet engines emits a force against the air. The plane's wheels are not powered. They would just be spinning a lot faster than normal when the plane hits its take-off speed.
#35
11-01-2006, 02:53 AM
RE: Riddle time! Airplane vs. conveyor
Being an avaiation enthusist and a science major with somewhat special interest i know it would not take off. its just as if it were flying 120 knots into a 20 knot wind the plane would only be flying at 100 knots because the wind would create resistance, same deal here 2 bodies in motion moving at the smae speed in opposite directions, they cancel each other out.
#37
11-01-2006, 04:40 AM
RE: Riddle time! Airplane vs. conveyor
ORIGINAL: SAudi
Being an avaiation enthusist and a science major with somewhat special interest i know it would not take off. its just as if it were flying 120 knots into a 20 knot wind the plane would only be flying at 100 knots because the wind would create resistance, same deal here 2 bodies in motion moving at the smae speed in opposite directions, they cancel each other out.
Being an avaiation enthusist and a science major with somewhat special interest i know it would not take off. its just as if it were flying 120 knots into a 20 knot wind the plane would only be flying at 100 knots because the wind would create resistance, same deal here 2 bodies in motion moving at the smae speed in opposite directions, they cancel each other out.
#38
11-01-2006, 02:09 PM
RE: Riddle time! Airplane vs. conveyor
saudi.. sorry to break it to ya, but youre incorrect. Speed does not equate to force. Theyre two seperate systems that arent cancelling each other.. If a plane was flying 2 inches above the ground while the conveyor was going the opposite direction would it cnacel each other out?
A great example if you dont see it yet.. If a plane was landing on the conveyor that matched the speed instantly, would the plane instantly just stop? no.. it would land pretty much like normal while the wheels spun really fast.
A great example if you dont see it yet.. If a plane was landing on the conveyor that matched the speed instantly, would the plane instantly just stop? no.. it would land pretty much like normal while the wheels spun really fast.
#39
11-01-2006, 02:11 PM
RE: Riddle time! Airplane vs. conveyor
saudi.. sorry to break it to ya, but youre incorrect. Speed does not equate to force. Theyre two seperate systems that arent cancelling each other.. If a plane was flying 2 inches above the ground while the conveyor was going the opposite direction would it cnacel each other out?
A great example if you dont see it yet.. If a plane was landing on the conveyor that matched the speed instantly, would the plane instantly just stop? no.. it would land pretty much like normal while the wheels spun really fast.
A great example if you dont see it yet.. If a plane was landing on the conveyor that matched the speed instantly, would the plane instantly just stop? no.. it would land pretty much like normal while the wheels spun really fast.
#40
11-01-2006, 03:11 PM
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RE: Riddle time! Airplane vs. conveyor
i say...let's just all get ON the airplane, sit in first class and order up a few cocktails. we can argue about where the plane will land!
nice avatar change. you must like motion.
nice avatar change. you must like motion.