Brain teaser
12-08-2006, 03:19 PM
#102
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I changed my mind. The plane will take off. The wheels just support the weight of the airframe before the airframe makes enough lift to take off. It makes no difference how fast the wheels below the plane spin, as long as they do spin (assuming magic indestructable wheels, bearings, and tires). It makes no difference if we explore frictional forces or not.
The plane below could NOT take off if we switched a magic current in place of the magic treadmill.
The plane below could NOT take off if we switched a magic current in place of the magic treadmill.
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12-08-2006, 03:29 PM
#104
4 pages?
Somebody send this in to the Mythbusters please.
Do wheel bearings become more inefficient the faster they spin? No (well too a point I supposed heat would play into it at the extreme).
Take a rollerskate and hold it on a treadmill while it is moving say 1mph. If I increase the speed of the treadmill to 25mph is there anymore effort needed to hold the rollerskate from going backwards? No move the rollerskate from the back of the treadmill to the front against the direction of the belt at 1mph, now do the same thing at 25mph. No more effort other than keeping it stable should be required.
So once the drag of the bearing is overcome the plane is free to take off.
Someone better try this with rollerblades and a treadmill!
Somebody send this in to the Mythbusters please.
Do wheel bearings become more inefficient the faster they spin? No (well too a point I supposed heat would play into it at the extreme).
Take a rollerskate and hold it on a treadmill while it is moving say 1mph. If I increase the speed of the treadmill to 25mph is there anymore effort needed to hold the rollerskate from going backwards? No move the rollerskate from the back of the treadmill to the front against the direction of the belt at 1mph, now do the same thing at 25mph. No more effort other than keeping it stable should be required.
So once the drag of the bearing is overcome the plane is free to take off.
Someone better try this with rollerblades and a treadmill!
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12-08-2006, 03:35 PM
#107
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Yes, the bearings have a design limit, and their friction/drag would increase (or at least heat would skyrocket) as they moved faster and faster and further outside of their design envelope.
Then again, if you have a magic treadmill runway, you'd have to assume magic bearings, too, I suppose...
Fuckkkkkkkkkkkk!!!
Then again, if you have a magic treadmill runway, you'd have to assume magic bearings, too, I suppose...
Fuckkkkkkkkkkkk!!!
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12-08-2006, 03:43 PM
#110
All right, we have a real world test.
I went in to my Airframes shop this morning and told a couple 2nd Class Petty Officers the I bet they couldn't erect a 100ft wide treadmill the entire length of the runway. They laughed and said "come back after lunch, sir."
Well, I did my morning sim and went back to the hangar after lunch. One of the guys had a brother over at Little Creek who is a SeaBee. They brought their entire battalion over and IN FACT built a 8,000 foot long treadmill on the runway. It was powered by an engine they stole out of a C-130 left unattended and could get the entire runway spinning up to about 140 knots... conveniently just above takeoff speed of a Hawkeye. I was impressed to say the least.
I told the Skipper about out little discussion here on the forum and he said, "We'll show those hippy non-believers how it's done. Freakshow (my callsign), you take our best plane and go for a spin."
So I grabbed two pilots who were in on the discussion the night before, one believer and one not. We fired up the plane and eased it out on to the treadmill... we gave the word and when we released the brakes, they engaged that C-130 engine and we were off... and we were moving down the runway... past the taxi-way and the hangar and the crowd of onlookers... then just before we were about to take-off at normal airspeed speed, the left tire exploded because it was going just under 300knots of groundspeed. We ran off the treadmill and into the previously mentioned unattended 3-engine C-130. We all survived uninjured, but as you can imagine... there's some fallout.
The three Mazda dealerships in town have been blacklisted.
The non-believers won't talk to me and are screaming about a conspiracy.
Popular Mechanics called and wanted to talk to the SeaBees about the runway they built, but they'd already disassembled it and had made a barbeque out of the engine they'd stolen.
I'm not allowed down in the Airframes shop anymore.
But at least i was right.
I went in to my Airframes shop this morning and told a couple 2nd Class Petty Officers the I bet they couldn't erect a 100ft wide treadmill the entire length of the runway. They laughed and said "come back after lunch, sir."
Well, I did my morning sim and went back to the hangar after lunch. One of the guys had a brother over at Little Creek who is a SeaBee. They brought their entire battalion over and IN FACT built a 8,000 foot long treadmill on the runway. It was powered by an engine they stole out of a C-130 left unattended and could get the entire runway spinning up to about 140 knots... conveniently just above takeoff speed of a Hawkeye. I was impressed to say the least.
I told the Skipper about out little discussion here on the forum and he said, "We'll show those hippy non-believers how it's done. Freakshow (my callsign), you take our best plane and go for a spin."
So I grabbed two pilots who were in on the discussion the night before, one believer and one not. We fired up the plane and eased it out on to the treadmill... we gave the word and when we released the brakes, they engaged that C-130 engine and we were off... and we were moving down the runway... past the taxi-way and the hangar and the crowd of onlookers... then just before we were about to take-off at normal airspeed speed, the left tire exploded because it was going just under 300knots of groundspeed. We ran off the treadmill and into the previously mentioned unattended 3-engine C-130. We all survived uninjured, but as you can imagine... there's some fallout.
The three Mazda dealerships in town have been blacklisted.
The non-believers won't talk to me and are screaming about a conspiracy.
Popular Mechanics called and wanted to talk to the SeaBees about the runway they built, but they'd already disassembled it and had made a barbeque out of the engine they'd stolen.
I'm not allowed down in the Airframes shop anymore.
But at least i was right.
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12-08-2006, 03:44 PM
#111
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Yes, and since the only part of the aircraft that couples it to the runway are the tires. The tires are only coupled to the aircraft through free spinning bearings. Thrust is applied and the ****** effer takes off.
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12-08-2006, 03:48 PM
#113
All right, we have a real world test.
I went in to my Airframes shop this morning and told a couple 2nd Class Petty Officers the I bet they couldn't erect a 100ft wide treadmill the entire length of the runway. They laughed and said "come back after lunch, sir."
Well, I did my morning sim and went back to the hangar after lunch. One of the guys had a brother over at Little Creek who is a SeaBee. They brought their entire battalion over and IN FACT built a 8,000 foot long treadmill on the runway. It was powered by an engine they stole out of a C-130 left unattended and could get the entire runway spinning up to about 140 knots... conveniently just above takeoff speed of a Hawkeye. I was impressed to say the least.
I told the Skipper about out little discussion here on the forum and he said, "We'll show those hippy non-believers how it's done. Freakshow (my callsign), you take our best plane and go for a spin."
So I grabbed two pilots who were in on the discussion the night before, one believer and one not. We fired up the plane and eased it out on to the treadmill... we gave the word and when we released the brakes, they engaged that C-130 engine and we were off... and we were moving down the runway... past the taxi-way and the hangar and the crowd of onlookers... then just before we were about to take-off at normal airspeed speed, the left tire exploded because it was going just under 300knots of groundspeed. We ran off the treadmill and into the previously mentioned unattended 3-engine C-130. We all survived uninjured, but as you can imagine... there's some fallout.
The three Mazda dealerships in town have been blacklisted.
The non-believers won't talk to me and are screaming about a conspiracy.
Popular Mechanics called and wanted to talk to the SeaBees about the runway they built, but they'd already disassembled it and had made a barbeque out of the engine they'd stolen.
I'm not allowed down in the Airframes shop anymore.
But at least i was right.
I went in to my Airframes shop this morning and told a couple 2nd Class Petty Officers the I bet they couldn't erect a 100ft wide treadmill the entire length of the runway. They laughed and said "come back after lunch, sir."
Well, I did my morning sim and went back to the hangar after lunch. One of the guys had a brother over at Little Creek who is a SeaBee. They brought their entire battalion over and IN FACT built a 8,000 foot long treadmill on the runway. It was powered by an engine they stole out of a C-130 left unattended and could get the entire runway spinning up to about 140 knots... conveniently just above takeoff speed of a Hawkeye. I was impressed to say the least.
I told the Skipper about out little discussion here on the forum and he said, "We'll show those hippy non-believers how it's done. Freakshow (my callsign), you take our best plane and go for a spin."
So I grabbed two pilots who were in on the discussion the night before, one believer and one not. We fired up the plane and eased it out on to the treadmill... we gave the word and when we released the brakes, they engaged that C-130 engine and we were off... and we were moving down the runway... past the taxi-way and the hangar and the crowd of onlookers... then just before we were about to take-off at normal airspeed speed, the left tire exploded because it was going just under 300knots of groundspeed. We ran off the treadmill and into the previously mentioned unattended 3-engine C-130. We all survived uninjured, but as you can imagine... there's some fallout.
The three Mazda dealerships in town have been blacklisted.
The non-believers won't talk to me and are screaming about a conspiracy.
Popular Mechanics called and wanted to talk to the SeaBees about the runway they built, but they'd already disassembled it and had made a barbeque out of the engine they'd stolen.
I'm not allowed down in the Airframes shop anymore.
But at least i was right.
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