riddle
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torbs wrote:
Here's oneSo there's two friends driving in one of their cars. They line up to race one of their buddies when all of a sudden both people in car suddenly die. Hint, the car isn't moving and nothing hit the car.
What happened?
I farted:icon_porc:
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They get shot yo
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they were in a dsm and it burst into flames and blew up andthey both died.
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XJHEAD wrote:
It will take offNo it won't.
Don't start with me on this one, either. Ask Faber.
EDIT: I'll make it quick and painless.
Unless there is sufficient windspeed to lift the aircraft off the ground, it will not leave the pavement. Wheel speed has nothing to do with it. As an aircraft mechanic, they teach you that the landing gear is there for the sole purpose of supporting the aircraft as it is on the ground, and during take off and landing.
However.
An airplane can run it's engines at full throttle and go nowhere. Every plane I have witnessed take off at Grand Forks AFB, RAF Mildenhall and Al Udeid AB will always power their engines to the max, and apply full brakes. When the brakes release, the plane moves forward with a pretty decent amount of force. Riding on a civilian passenger jet won't show that because of the seat cushions. Riding in a KC-135 will show you that, because you sit on the side of the jet, and it throws you back like a subway train would, but with more force.
If the wheels are spinning, and the fuselage is not moving, no lift will take place. There has to be airspeed working against the leading edge of the wing for the bernouilli effect to work. If it's sitting on a conveyor belt, it will not move. Period.
-Peter
1991 240SX
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AFSil80 wrote:
No it won't.Don't start with me on this one, either. Ask Faber.
EDIT: I'll make it quick and painless.
Unless there is sufficient windspeed to lift the aircraft off the ground, it will not leave the pavement. Wheel speed has nothing to do with it. As an aircraft mechanic, they teach you that the landing gear is there for the sole purpose of supporting the aircraft as it is on the ground, and during take off and landing.
However.
An airplane can run it's engines at full throttle and go nowhere. Every plane I have witnessed take off at Grand Forks AFB, RAF Mildenhall and Al Udeid AB will always power their engines to the max, and apply full brakes. When the brakes release, the plane moves forward with a pretty decent amount of force. Riding on a civilian passenger jet won't show that because of the seat cushions. Riding in a KC-135 will show you that, because you sit on the side of the jet, and it throws you back like a subway train would, but with more force.
If the wheels are spinning, and the fuselage is not moving, no lift will take place. There has to be airspeed working against the leading edge of the wing for the bernouilli effect to work. If it's sitting on a conveyor belt, it will not move. Period.
What people fail to see is that it says the conveyor belt moves backwards at the same speed as the plane moves forward....basically the wheels spin twice as fast because of this and so long as the wheel bearings don't overheat and seize up before the plane generates enough airflow over the wings to achieve lift, the plane will fly. PERIOD.
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http://fargostreet.com/forums/showthread.php?t=5245&highlight=plane+conveyor+belt
Think about it this way if you are driving a motorcycle with a side car on it at 50MPH and the conveyor is ONLY on the side car you can still drive the motorcycle at 50MPH, however the sidecars wheel(s) will be traveling 100MPH. Same principal applies here. The planes motors providing thrust would be the motorcycle in above analogy and the planes wheels would be the side car. It is very possible for the plane to take off.
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The one thing I don't get is what the wheels have to do with anything, so they are moving 100mph, how is that moving any air over/under the wings?
Edit: Or in other words, how is the airplane moving forward relative to its static spot on the ground? How do the wheels moving at some speed have anything to do with lift?
I see it as like a treadmill. If you are running at 7mph, and the tread is going backwards at 7mph, you are in fact staying in the same spot relative to the ground, no matter how fast your feet are going.
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XJHEAD wrote:
Engine thrust is propelling the craft not the wheelsLift has nothing to do with how much thrust. Different aicraft require different amounts of thrust per weight.
It's all about the windspeed hitting the leading edge.
So again, if the wheels are freerolling and the conveyor belt is doing the same, the plane won't move. The wheels keep the airplane supported until it builds up enough airspeed for the bernoulli effect to take place.
If it can't hit that speed, and it won't while it sits on a belt that can keep up, there will be no forward motion.
-Peter
1991 240SX
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nissankingcab wrote:
I see it as like a treadmill. If you are running at 7mph, and the tread is going backwards at 7mph, you are in fact staying in the same spot relative to the ground, no matter how fast your feet are going.Exactly!
There is no wind flowing against you as if you were running on a track! Therefore, lift cannot occur!
-Peter
1991 240SX
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XJHEAD wrote:
Engine thrust is propelling the craft not the wheelsI never said it was.
However, the wheels are relative to the aircraft's speed. It's an odd situation, because they are directly involved because of their purpose in takeoff, but at the same time, they aren't the determining factor in flight since they have nothing to do with the aircraft's airflow, which causes flight.
-Peter
1991 240SX
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Oh, and I am off work now for the weekend. I have no plans since I am on standby.
If it takes me creating MS paint masterpieces to illustrate what is in my head, so be it. You have to think out of the box on this, and a little knowledge of aircraft helps. Faber presented this problem to me last night, and he'll tell you, I went on for the better part of an hour or so, debating with myself and reading the shit on MNSportCompacts. When I woke up, I stood firm in my beliefs that it cannot get off the ground.
-Peter
1991 240SX
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AFSil80 wrote:
Exactly!There is no wind flowing against you as if you were running on a track! Therefore, lift cannot occur!
Yes, but Peter, the wheels do not create any thrust of any kind. Think of it like this: Before the landing gear retracts, the wheels are spinning by the wind movement, although not as fast as say the treadmill will make them spin, they are still moving in the same fashion and will theoretically increase with wind speed but the plane will be unbothered. If the plane starts moving, which it will, it will take off. Yes, it won't take off without moving forward, but I don't think thats what people are trying to prove. If they are, then thats a totally different story and yes you are right. I think you might be trying to prove the wrong thing. If a runway was a HUGE treadmill, it will take off. The wheels will not provide enough resistance to keep it from moving.
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a harrier doesnt need to be moving forward at all to take off, its all about thrust. with enough of it, it will move forward because hey, three pieces of rubber are no match for 90000lbs of thrust
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