A question...

[SpeedingFirebird]

Originally posted by MTMike:
[ Friction is what would move the plane on the treadmill with no engine thrust. As SOON as the engines make enough thrust to overcome the small amount of friction allowing the plane move backwards on the treadmill, it will propel forward.

Objects in rest remain at rest until a force is applied on it. As soon as the treamill starts to move, the friction is the force that keeps the wheels from turning and would allow the plane to move backwards. If there was absolutely no friction in the wheels, the plane would sit stationary as the treadmill moved because there would be no force exerted on it causing it to move backwards

Physics 101.... live it. Learn it. Love it.

OHHHHHHH! I get it now. The force is applied to the air, NOT the wheels. For the love of dog, somebody [img]graemlins/twak.gif[/img] me.

I have SEEN the light! And the light is Good.

thanks for that good explination. I slept through college physics. It was at 8am after all.

[MTMike]

Real world example, proof it will take off for all the same reasons I've (and many others) have said

http://www.avweb.com/news/columns/191034-1.html

[teal99camaro]

my physics professor says the plane will not lift.

[MTMike]

Originally posted by teal99camaro:
my physics professor says the plane will not lift.

He's wrong :D

[teal99camaro]

my friend whose a junior at embry riddle aeronautical engineering school says you're wrong.. hes an aeronautical engineer major

[MTMike]

Originally posted by teal99camaro:
my friend whose a junior at embry riddle aeronautical engineering school says you're wrong.. hes an aeronautical engineer major

A degree means nothing if you don't understand simple physics

Have him prove it in a real world application then. Someone already proved me right in my link above.

[Merlin]

I am doing my PhD in Aerospace at Georgia Tech (precisely in aerodynamics) but it is not like it takes a rocket scientist to figure this one out since this is one of those DUH! questions.

If the treadmill is moving at exactly the same speed but in opposite direction then the effective velocity over the wings is ZERO and there can be no lift produced through a classical wing. No effective velocity, no circulation, NO LIFT.

Want more proof? Go run in a treadmill and stretch out your arms like wings and tell me if you feel air flowing over and under your arms. The answer is NO.

[MTMike]

Originally posted by Merlin:
I am doing my PhD in Aerospace at Georgia Tech (precisely in aerodynamics) but it is not like it takes a rocket scientist to figure this one out since cause this is one of those DUH! questions.

If the treadmill is moving at exactly the same speed but in opposite direction then the effective velocity over the wings is ZERO and there can be no lift produced through a classical wing.

Want more proof? Go run in a treadmill and stretch out your arms like wings and tell me if you feel air flowing over and under your arms. The answer is NO.

Running on a treadmill and wearing free-rollling rollerskates on a treadmill with jet engines under your arms are two totally different things. Read all 7 pages, i'm not describing it again.

http://www.avweb.com/news/columns/191034-1.html

Someone proved it with a real plane and a real 3000' treadmill. What more do you people need?

[teal99camaro]

dude
MTMike get on aim. I have an engineer who wants to talk to you
elvinerau187 is his screenname

[LD]

Originally posted by Merlin:
I am doing my PhD in Aerospace at Georgia Tech (precisely in aerodynamics) but it is not like it takes a rocket scientist to figure this one out since this is one of those DUH! questions.

If the treadmill is moving at exactly the same speed but in opposite direction then the effective velocity over the wings is ZERO and there can be no lift produced through a classical wing. No effective velocity, no circulation, NO LIFT.

Want more proof? Go run in a treadmill and stretch out your arms like wings and tell me if you feel air flowing over and under your arms. The answer is NO.

lol duh
did you even read mtmikes link?
read that... then try to disprove it

[Merlin]

Originally posted by MTMike:
</font><blockquote>quote:</font><hr />Originally posted by Merlin:
I am doing my PhD in Aerospace at Georgia Tech (precisely in aerodynamics) but it is not like it takes a rocket scientist to figure this one out since cause this is one of those DUH! questions.

If the treadmill is moving at exactly the same speed but in opposite direction then the effective velocity over the wings is ZERO and there can be no lift produced through a classical wing.

Want more proof? Go run in a treadmill and stretch out your arms like wings and tell me if you feel air flowing over and under your arms. The answer is NO.

Running on a treadmill and wearing free-rollling rollerskates on a treadmill with jet engines under your arms are two totally different things. Read all 7 pages, i'm not describing it again.

http://www.avweb.com/news/columns/191034-1.html

Someone proved it with a real plane and a real 3000' treadmill. What more do you people need? </font>[/QUOTE]No it is not, ultimately what matters is the effective speed over the wings. PERIOD. Unless he is using the jet engines to affect the flow over the wing through a suction or blowing.

I am not disagreeing that the plane flew or not but it is pointless because my point stands. No flow over the wing means no lift. Plain and simple, unless he managed to get the air moving some other way using the engine aka blowing or suction. Which is technology that has been used OVER and OVER again, hardly any WOW! there

[Merlin]

I can't believe I am even bothering with this sh-it

[MTMike]

My dad who is a pilot and an engineer agrees with me.

I'm not near a comptuer w/ IM right now

No it is not, ultimately what matters is the effective speed over the wings. PERIOD. Unless he is using the jet engines to affect the flow over the wing through a suction or blowing.

I am not disagreeing that the plane flew or not but it is pointless because my point stands. No flow over the wing means no lift. Plain and simple, unless he managed to get the air moving some other way using the engine aka blowing or suction. Which is technology that has been used OVER and OVER again, hardly any WOW! there

Tell me then how fighter jets take off THE BACK of a moving Air Craft Carrier? The aircraft carrier's already going 50 knots forward, so according to you that plane could never get moving fast enough to take off because it would never get moving with it sitting on the deck of the ACC already moving backwards.


Forget the wings forget the lift, answer me this

All things else the same, could the plane move forward on the treadmill while being pushed with a jet engine?

[teal99camaro]

the only reason the plane in the experiment flew is because the treadmill started once the plane was already at 25 mph. This is cheating the question. they have to start at the same tme and have the same acceleration throughout


excerpt from the article

A few moments later, the roaring Continental, spinning that wooden Sensenich prop, has accelerated the J-3 and Manfred to 25 mph indicated airspeed. He and the airplane are cruising past the cheering spectators at 25 mph, while the conveyor has accelerated to 25 mph eastbound, yet it still has no way of stopping the airplane's movement through the air. The wheels are spinning at 50 mph, so the noise level is a little high, but otherwise, the J-3 is making a normal, calm-wind takeoff.

[ December 01, 2005, 05:59 PM: Message edited by: teal99camaro ]

[teal99camaro]

dude, i'm in highschool and i know tis not possible for a plane with no ground speed to take off unl;ess there is a headwind that is strong enough to lift the plane.