Funny, Strange, Random Pics

[SalaciousTunare]

Originally Posted by Xurlitil

^Hey look, I just countered every point you just made in that post while I was making mine. Look at how stupid you are.



PhysOrgForum Science, Physics and Technology Discussion Forums -> Plane on conveyor... Will it ever take off?

Somewhere in that 600 page thread there is a post that mathematically proves beyond any doubt that the plane will take off. Someone got all the specs on a commercial jet's landing gear, very expensive bearings included, and calculated out how much drag they create.

The answer is: the drag created by landing gear is so insignificant compared to the thrust from the planes engines that it doesn't make a fucking bit of difference.

So even if the conveyor belt could move in the opposite direction at a thousand miles an hour, the wheels would just be spinning that much faster as the plane moves forward and gains enough speed for takeoff.

Directly from your link...
Posted by Justavian

This is really the only relevant thing to consider. The ground speed of the aircraft is not important, nor is the amount of thrust the engines develop. If a plane's take off speed is 140mph, that is the speed the air must flow over the wing in order to develop the lift required to take off. If a plane has a ground speed of 140 mph, but also has a tail wind of 140mph, that means the plane will not be moving relative to the air. If the plane were to turn around, into the wind, it could take off with zero ground speed and zero thrust.

This is why aircraft carriers turn into the wind before launching any planes (and why they will generally get up to full speed, to add to the air speed over the deck). It allows the planes to take off with a lower 'ground' speed, so that the catapault can exert less effort. The plane may only be moving about 100mph relative to the deck, but the extra 35mph of the ship + 10mph wind will allow the planes to get airborne. Turn the catapault around, and now that 100mph deck speed is only 65mph air speed. You're gonna lose that aircraft.

This is ENTIRELY what the whole experiment is about. A runway in motion, the exact fucking same as an aircraft carrier.

This is the exact fucking same.

How you cannot see a moving runway would have this effect on a takeoff is beyond me.

If a fucking aircraft carrier was infinitely long in this example... and traveled 140mph against the direction the plane was trying to takeoff, the plane would reach 140mph while still on the aircraft carrier (treadmill, conveyor whatever), it would have an effective air speed of 0 and would not have sufficient lift to go airborn. It is that simple.

[aychamo_aycono]

Wheels are decoupled from the plane. I love the use of pseudo-physics in people's answers saying it wouldn't take off.

[dy fey]

Originally Posted by SalaciousTunare

not fsr pics

no way, hey there's some guy on the internet i just saw who said time is real and not a construct created by man to quantify change omg you can still catch him if you go now

[Screamfeeder]

Originally Posted by SalaciousTunare

Directly from your link...
Posted by Justavian


This is ENTIRELY what the whole experiment is about. A runway in motion, the exact fucking same as an aircraft carrier.

This is the exact fucking same.

How you cannot see a moving runway would have this effect on a takeoff is beyond me.

If a fucking aircraft carrier was infinitely long in this example... and traveled 140mph against the direction the plane was trying to takeoff, the plane would reach 140mph while still on the aircraft carrier (treadmill, conveyor whatever), it would have an effective air speed of 0 and would not have sufficient lift to go airborn. It is that simple.

pictures>words

[aychamo_aycono]

^^ Brilliant

[Screamfeeder]

Yeah but I forgot to mention that the force acting against the wheels is TINY compared to the rest of the plane.

Oh well.

WILL IT TAKE OFF?!?!?!?!

[Tallyn]

Exactly. As far as the examples with the aircraft carrier, the catapult is equivalent to the treadmill only if the plane's brakes are on. There's a reason they attach the catapult cables to the body of the plane and not the wheels.

[TheOkapi]

God, I can't believe people are STILL arguing about that shit. Who the fuck cares?

[lendarios]

Also if it help visualize the reason picture this. It also helps separate the similarity or a car and an air plane.


Imagine plane in a ice field. A perfectly surface where everything will slide off, with almost zero friction.

Now put a car and a plane next to each other.
The plane will move forward even if its wheels are not turning ( brakes on, wheels sliding on ice) since it does not generate movement from friction.
Car will spin like crazy never moving forward due to lack of friction.
So, the place Does not require Any friction from the ground to generate movement, or air flow. It generates enoghh from its engine.

Now if you have a tread mill, you have eliminated the horizontal movement of the plane, but the plane is still moving air using its turbines, It will take off when enough air provides lift.

[Tallyn]

Originally Posted by SalaciousTunare

If a fucking aircraft carrier was infinitely long in this example... and traveled 140mph against the direction the plane was trying to takeoff, the plane would reach 140mph while still on the aircraft carrier (treadmill, conveyor whatever), it would have an effective air speed of 0 and would not have sufficient lift to go airborn. It is that simple.

The aircraft could indeed reach 140 mph relative to the deck and have 0 airspeed. This is achieved when the output of the engine exactly counters the friction on the wheels generated by the moving deck. However, this is not the experiment in question. The question is, can an airplane take off AT ALL, to which the answer is yes. The force of friction on the wheels is tiny when compared to the actual output of the engine. Engaging the engine to point where you would achieve 140 mph relative to a stationary runway would probably net you 138 or 139 mph (numbers from my ass) on a moving deck, and you'd still take off.

[Kais[]]

Originally Posted by Tallyn

Exactly. As far as the examples with the aircraft carrier, the catapult is equivalent to the treadmill only if the plane's brakes are on. There's a reason they attach the catapult cables to the body of the plane and not the wheels.

yeah, the reason being the wheel supports can't handle the stress the catapult generates. How wheels works has nothing to do with the catapult system, are you people seriously this retarded?

[Kais[]]

Originally Posted by Tallyn

The aircraft could indeed reach 140 mph relative to the deck and have 0 airspeed. This is achieved when the output of the engine exactly counters the friction on the wheels generated by the moving deck.

Except that the thrust of the engines is acting on the plane, not turning the wheels. The wheels have 0 power applied to them, they have the leisure to rotate freely regardless of groundspeed (treadmill) or relative speed of the airplane to the ground. The engine thrust works on the body of the plane as a whole, moving the plane forward until enough air moves over the wings to produce lift.

aaaaaaaaaaaaaa

fuck you for making me explain applied middle school physics. This is why these debates happen, the temptation to correct falsity is too great.

[Abysmal]

ffs why doesn't someone just build a model fucking airplane and stick it on a treadmill? in real life i don't think this would work because the wheels would break off or pop at some speed and the plane would tumble backwards once the body makes contact with the treadmill. if we have imaginary wheels that can run forever and not explode then maybe it would work. real life: no. imaginary super wheels: yes.

[Vatoreus]

VVVVVVVV

[Dethfang]

this applies: