will a plane be able to take off on a conveyer belt? find out soon. (1 Viewer)

[diat150]

http://community.discovery.com/eve/forums/a/tpc/f/9801967776/m/5321919039/p/1

Airplane Hour
(Weds., December 12 at 9 PM ET/PT)
Adam and Jamie find out if either of them can safely land a Boeing 747-400 on a runway in varying weather conditions. Meanwhile, Kari, Tory and Grant risk life and limb to investigate skydiving myths regularly featured in Hollywood action films. Is it possible to catch up with someone in freefall if that person jumps out a plane before you do? Can you really hold a conversation during freefall? And would you survive if you opened your parachute only a few feet off the ground? Finally, Adam and Jamie carefully navigate their way through a myth that has baffled everyone from web bloggers to pilots. If a plane is traveling at takeoff speed on a conveyor belt, and the belt is matching that speed in the opposite direction, can the plane take off? Extensive small-scale testing with a super treadmill and a nearly uncontrollable model airplane don't completely resolve the myth, so our flight cadets supersize the myth with help from a willing pilot and his Ultralight flying machine.


Im not exactly sure how I feel on this one. at first I thought the plane would take off without a doubt. but after looking at the effects of a tailwind on a plane's takeoff I realize there are alot of factors that will come into play.

>>a tailwind that is 10 percent of the takeoff airspeed
will increase the takeoff distance approximately
21 percent.

if the conveyor is moving at the exact same speed as the plane is attempting to go forward, it seems like the tailwind that is produced will cancel out the momentum the plane is trying to achieve. should be interesting.

 

[CT Saints Fan]

http://community.discovery.com/eve/forums/a/tpc/f/9801967776/m/5321919039/p/1

Airplane Hour
(Weds., December 12 at 9 PM ET/PT)
Adam and Jamie find out if either of them can safely land a Boeing 747-400 on a runway in varying weather conditions. Meanwhile, Kari, Tory and Grant risk life and limb to investigate skydiving myths regularly featured in Hollywood action films. Is it possible to catch up with someone in freefall if that person jumps out a plane before you do? Can you really hold a conversation during freefall? And would you survive if you opened your parachute only a few feet off the ground? Finally, Adam and Jamie carefully navigate their way through a myth that has baffled everyone from web bloggers to pilots. If a plane is traveling at takeoff speed on a conveyor belt, and the belt is matching that speed in the opposite direction, can the plane take off? Extensive small-scale testing with a super treadmill and a nearly uncontrollable model airplane don't completely resolve the myth, so our flight cadets supersize the myth with help from a willing pilot and his Ultralight flying machine.


Im not exactly sure how I feel on this one. at first I thought the plane would take off without a doubt. but after looking at the effects of a tailwind on a plane's takeoff I realize there are alot of factors that will come into play.

>>a tailwind that is 10 percent of the takeoff airspeed
will increase the takeoff distance approximately
21 percent.

if the conveyor is moving at the exact same speed as the plane is attempting to go forward, it seems like the tailwind that is produced will cancel out the momentum the plane is trying to achieve. should be interesting.

It shouldn't be able to take off. How fast the wheels are turning have nothing to do with creating enough lift for the plane to get off the ground. What matters is the air moving over the wings. If the plane is stationary (on a treadmill), then there is no lift being generated.

The only way they may be able to make it happen is if the ultralight has a high hp/weight ratio. It's possible that with the engine running at full speed, it may be able to accelerate so quickly that it will create enough lift when the air does start moving past the wings, to lift what little weight it has.

But I would seriously doubt that any regular plane could pull it off.

 

[diat150]

yeah i dont think the wheels have anything to do with it, the main factor will be the tailwind that is generated by the conveyer going backwards wihile the plane tries to move forward. it should be interesting.

 

[bclemms]

There is no way a normal plane would be able to take off. It would be the same as a plane "power braking" and when letting off the brakes it takes off instantly. If it could be done our military wouldn't have to worry about buying planes like the Harrier.

 

[Taurus]

You could do it if the plane was in a giant wind tunnel.

 

[CT Saints Fan]

You could do it if the plane was in a giant wind tunnel.

Yep. And if you did, technically speaking, not only wouldn't you need the treadmill, you wouldn't even need an engine. You could lift a glider in a wind tunnel.

 

[CT Saints Fan]

And just in case anyone is wondering, Kari Byron is smoking hot. And on top of that, she can build cool stuff, and then blow it up too. What more could you ask for?

 

[Bundok Saint]

I'm glad they're finally tackling this myth! It's a subject that has been discussed ad nauseum on an aviation message board that I belong to, and the general consensus is that the plane does take off.

I'll have to dig through that thread on the other message board and post an explanation when I have more time.

 

[Taurus]

I'm glad they're finally tackling this myth! It's a subject that has been discussed ad nauseum on an aviation message board that I belong to, and the general consensus is that the plane does take off.

I'll have to dig through that thread on the other message board and post an explanation when I have more time.

Please do, because the idea of achieving takeoff when the airspeed indicator reads zero makes no sense to me.

 

[runDeucerun]

It shouldn't be able to take off. How fast the wheels are turning have nothing to do with creating enough lift for the plane to get off the ground. What matters is the air moving over the wings. If the plane is stationary (on a treadmill), then there is no lift being generated.

The only way they may be able to make it happen is if the ultralight has a high hp/weight ratio. It's possible that with the engine running at full speed, it may be able to accelerate so quickly that it will create enough lift when the air does start moving past the wings, to lift what little weight it has.

But I would seriously doubt that any regular plane could pull it off.

I might be wrong, but I don't think they are talking about the plane being stationary... this could be used reversed tho, for planes with their landing gear failing, landing ona conveyer belt could prevent alot of crashes caused by landing gear malfunction.

 

[Diabolik The Saint]

I would say you have to have enough thrust going through the turbines that would create lift with the flaps down. Kinda like a catapault lauching Kingfishers off the rear gun turrets of the Old Style Arizona class Battleships. Didn't the Wright brothers lauch from a belt with a weight

 

[diat150]

I really dont know what to think either way. if the plane can overcome the tailwind that is generated by the conveyer moving backwards it will takeoff. if it cant then it wont takeoff.

 

[gumbeau]

This one is so simple it is ridiculous.

Airplanes fly by generating air moving over the lift generating surfaces.

Go outside and run really fast.....check if there is a nice breeze on your face.

Now run really fast on a treadmill......note the absence of a breeze on your face.

The Navy already has tested this. Its called an aircraft carrier.

 

[Devildog]

Kinda like a catapault lauching Kingfishers off the rear gun turrets of the Old Style Arizona class Battleships. Didn't the Wright brothers lauch from a belt with a weight

The Vought-Sikorsky Kingfisher was launched off of battleships using a steam catapult.

 

[Bleu Raeder]

I really dont know what to think either way. if the plane can overcome the tailwind that is generated by the conveyer moving backwards it will takeoff. if it cant then it wont takeoff.

There is no tailwind created by the conveyor belt, nor is there any tailwind during a standard take-off. Typically all aircraft ake-off into the wind if there is any, that is a headwind.

This is also why there are measurements for airspeed and groundspeed. An aircraft flying into a 10 mile per hour headwind at 100 miles per hour has an airspeed of 110 MPH with a groundspeed of 100 miles per hour. A tailwind (from behind the aircraft) increases ground speed relatively.