/sci/ - Science & Math

derp

>>1532767
srs?

engine speed < or = to treadmill speed, no flight
engine speed > treadmill speed, flight

engine speed > 0 : flight

THE GOD DAMN WHEELS DO NOT POWER THE PLANE FORWARD. THEY WILL ROTATE AS FAST AS THEY NEED TO FOR THE PLANE TO PICK UP SPEED.

>>1532796
the wheels would only spin as fast as the treadmill if something were holding the plane in place. Therefor the engine output must first counterbalance the treadmill

>>1532800
assuming the treadmill is infinite, it would eventually overcome the treadmill at any level of thrust

>>1532796
THIS. The whole point of WHEELS on a plane is they don't transmit friction forces from the ground to the plane.

>>1532802
which is essentially what i meant with
>engine speed > treadmill speed, flight

>>1532811
you should get better at meanting things

>>1532809
you put a roller skate on a treadmill and turn the treadmill on, does the skate stay in the same place? No it moves backwards.

Plane wouldn' take off, for the wings would break thanks to treadmill.

>>1532814
Sure, you can't eliminate all friction, but a well lubed scake takes very little force to keep it on the treadmill.

Back to the plane, the force needed to overcome the pull of the treadmill at any speed is tiny compared to the thrust of the plane.

Can we assume frictionless bearings in the wheels OP?

>>1532828
You don't have to, real world bearing as low-friction enough.

i five year old could tell you it would not take off because air is not hitting the wings. it needs propulsion from the air hitting it. 17fag reporting in.

recaptcha: the resentful

>>1532945
Five year olds get a lot of things wrong. Seventeen year olds too apparently.

The obvious solution is turn the plane around.

Retards.

bernoulii effect how does it work?

> It would not take off because air is not hitting the wings. it needs propulsion from the air hitting it.
Lolwut?

>>1532945
14yearoldfag

it flies with airspeed, not fucking ground speed. OP's principal can be redone if you replace the treadmill with a giant fan of a sort.

>>1533005
what? Who are you quoting, because no one in the thread said that.

Wait..... woudldn't the plane go from 0-70 in a fraction of a second once the wheels leave the treadmill?

Why do planes fly?
Lift.
Figure the rest out yourself.

>>1533015
>>1532945

>>1533021
Lift comes from air flow over the wings.
Air flow comes from forward air speed.
The treadmill can't transmit enough rearward force to overcome the thrust of the engines. Wheels are designed to transmit almost no friction from the ground to the plane.
Net force is forward, producing acceleration, airspeed, air flow, and lift.

>>1533033
Lets ask mythbusters to be sure, they deal with bullshit science day in and day out

>>1533023
I hereby apologize to you. Have a lulz, pic related.

>>1533041
they already did

the plane takes off, even to the pilot's surprise

people in general are pretty stupid

>>1532814

Rollerblades don't have jet engines attached. Or wings.

TL;DR: Rollerblades != airplanes.

>>1533141

>TL;DR: Rollerblades != airplanes.

Best post I've seen on the internet in a long time. I lol'd

>>1533120
No it didn't, don't lie.

If it's staying in the same place there is no air moving under and over the wings, which is how a plane leaves the ground

http://www.howstuffworks.com/airplane.htm

captcha:cockpits oak

>>1533201
We all know that. But it doesn't stay in the same place. Thrust from the engines overcomes friction from the ground, because of the wheels. Wheels are friction reducing devices.

Replace wheels with skis, does it take of?

Barring stupid oversights like the wings fitting past the handles at the front, the realistic answer is, "depends."

If the treadmill is run up to some critical speed, the plane will take off, because the engines don't care what speed the treadmill runs at: the treadmill doesn't change the position of the air, and it's the engines manipulating the air that causes forward motion.

However, if the treadmill is fast enough, the friction in the wheels' bearings will eventually melt or damage the wheels, causing them to lock or otherwise lose their ability to spin. Suddenly, the treadmill's backward speed becomes relevant, and if running fast enough, the plane's engines won't overcome the ground friction. Most likely the plane in this case would tumble forward and get wrecked.

>>1533236
Anotherfag here, but you and him are both right.

The differing opinions are caused by differing points of view.

While you think the question like this "Can a plane take off if the runway is moving under it?", he sees it as "Can a plane take off if the only thing moving is the runway under it?", the engines having nothing to do with the second scenario.

Both viewpoints are valid, owing to the lack of boundaries and also the implied conditions of the original picture.

>>1533246
Also: back when this first was a big hit on /b/, I made this picture to put the issue to rest once and for all.

It can't take off, because the aeroplane wighs it down.

captcha is getting a bit... militaristic: re-enlist US

Ask people that post stupid shit like this if they can fly by carrying themselves.

>>1533292

I tried to lift myself up while standing in a basket once, it didn't work. Empiric science at its best.

>>1533300

YOU'RE NOT AN AIRPLANE EITHER