COULD A PLANE TAKE OFF FROM A CONVEYER BELT? - PLEASE READ

[marine ices]

 definitely, if it can take-off vertically

[hard]

fuck mao man like mannnnnnnn

[enwiabe]

I might have made some critical errors though. I don't have enough time to think this over again in terms of energy, but I have a feeling that the extra rotational energy of the wheels come from the energy of the conveyor belt, which has a driving force, and things should balance. But again taking off can be considered as a 'collision' between Earth and the plane, and there need to be consideration on how this 'collision' takes place in terms of momentum as well... so...

As far as I'm aware, the wheels of a commercial liner are powered by an internal combustion engine, and it's only right before takeoff that the turbines kick in and produce that quarter million pounds of thrust.

I could be wrong though, we don't do undercarriage design for 2 years.

[Mao]

I might have made some critical errors though. I don't have enough time to think this over again in terms of energy, but I have a feeling that the extra rotational energy of the wheels come from the energy of the conveyor belt, which has a driving force, and things should balance. But again taking off can be considered as a 'collision' between Earth and the plane, and there need to be consideration on how this 'collision' takes place in terms of momentum as well... so...

As far as I'm aware, the wheels of a commercial liner are powered by an internal combustion engine, and it's only right before takeoff that the turbines kick in and produce that quarter million pounds of thrust.

I could be wrong though, we don't do undercarriage design for 2 years.

mm, yeah.. If that's the case then I am very wrong. I'm relying purely on the fact that the wheels are freely rotating.

However, having been on commercial flights many times, I'm fairly sure that on take off run, the main engines are going full from the start of the run [at which point you are thrown against the back of your seat... or when you get good at it, you stay in the position uncomfortably reading the extremely boring magazine while trying have that 'Ive-done-this-so-many-times' look].

But again, I don't know.

[excal]

 definitely, if it can take-off vertically

OH YEAH

[excal]

I might have made some critical errors though. I don't have enough time to think this over again in terms of energy, but I have a feeling that the extra rotational energy of the wheels come from the energy of the conveyor belt, which has a driving force, and things should balance. But again taking off can be considered as a 'collision' between Earth and the plane, and there need to be consideration on how this 'collision' takes place in terms of momentum as well... so...

As far as I'm aware, the wheels of a commercial liner are powered by an internal combustion engine, and it's only right before takeoff that the turbines kick in and produce that quarter million pounds of thrust.

I could be wrong though, we don't do undercarriage design for 2 years.

My lay understanding is that the wheels are indeed powered, but used only to taxi into position. I think the wheels would be fairly useless as the propelling force when airborne.

Seeing as the 747 is already in a position to fire its jet engines on the conveyor belt, I don't see why it couldn't take off (notwithstanding any mechanical issues around the wheels being spun in the opposite direction). If anything, it will result in an increase to the amount of friction on the jet.

Also, I like the way it's put in this quote:

In contrast, a plane's wheels aren't motorized; their purpose is to reduce friction during takeoff (and add it, by braking, when landing). What gets a plane moving are its propellers or jet turbines, which shove the air backward and thereby impel the plane forward. What the wheels, conveyor belt, etc, are up to is largely irrelevant.

Source: http://www.straightdope.com/columns/read/2638/an-airplane-taxies-in-one-direction-on-a-moving-conveyor-belt-going-the-opposite-direction-can-the-plane-take-off

[dcc]

HARRIER JUMP JET!!!

[StephenBM]

It won't work

[schnappy]

Bumping a thread without reason is one thing, bumping a thread just to troll is another.

I pondered this for a while actually, i understand perfectly that the driving force in the typical question (light aircraft - no fancy turbines and powered wheels) posed is from the propellor and not the wheels. I do protest however that the motion from the propeller has to push air over the airfoil to create lift - the propeller cant just provide the forward force and have the airfoil do its bit against still wind.

[StephenBM]

Then what do turbine a/c do such as the F-22 for example...It's all because of the forward momentum. The prop/turbo-prop/turbine or whatever just supply the forward force for the a/c, then the air flow over and under the wing does the rest.

LOL I'm pretty sure this is right! I want to be a airline pilot so lets hope so!!