Science!! Fucking magnets, how do they work?
- Thread starter Flunklesnarkin_sl
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No, there is a million and one fucking problems, but arguing physics about magical instruments is my last straw. You win, real plane doesn't take off when Gandalf decrees it so.
It's like you recognize the problem the whole time, and then just decide out of nowhere that they don't exist. I was allowing a lot of suspicious "ifs" to even entertain this last notion, but I'm sick of it.
It's like you recognize the problem the whole time, and then just decide out of nowhere that they don't exist. I was allowing a lot of suspicious "ifs" to even entertain this last notion, but I'm sick of it.
Tuco
I got Tuco'd!
- 47,386
- 80,809
I'd say that describes me pretty well. Bottom line is the plane doesn't take off, but if you assume N things, what speed would the treadmill have to go to ground the plane? The best answer is 470mph.
When I learned to fly seaplanes, my instructor explains the takeoff: "We open the throttle, lift up the water rudders (maybe these first two are reversed. It's been awhile), increase speed, ride up on the water bubble that forms in front of us, then move to the top of it and hydroplane." At which point I stopped him and said, "If we are hydroplaning, how can we control where we're going?".
He laughed and said, "The air surfaces (air rudder, etc) of the plane will be handling that. We're good."
Turns out that hydroplaning on takeoff and landing is fun as hell.
He laughed and said, "The air surfaces (air rudder, etc) of the plane will be handling that. We're good."
Turns out that hydroplaning on takeoff and landing is fun as hell.
Palum
what Suineg set it to
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No, because the thrust to weight ratio of one of those little balsa airplanes is like 280 trillion to one...
Weight is a huge issue with real airplanes. Even if you maintain your CG, being overweight will cause you to run out of runway even if you nurse the thing to keep the wings from shearing off from dynamic load. You have to generate enough lift to counteract gravity, obviously. The more lift you have, the higher your drag and the slower you go. Hence using flaps on short field take offs. But you still have to actually reach vR, you are just trading airspeed for lift in order to reduce runway length. Point being, a treadmill which gives you this 'unlimited' theoretical runway by spinning super fast is irrelevant because the only thing it is putting force on is the bearings in the wheels. It must also be physically long enough for the airplane to achieve a high enough RELATIVE WIND over the wings to cause lift. This is therefore a magical treadmill, speed issues notwithstanding.
An airplane will take off at zero velocity with enough wind over the wings. See jetliners flipping entire GA ramps full of small airplanes because they goose the engines on a corner without realizing it. The airplanes would simply slide without the airfoils. The treadmill speed is a red herring, the plane will never take off because treadmills aren't long enough.
Tuco
I got Tuco'd!
- 47,386
- 80,809
(though this isn't really a treadmill, it pulls the plane and has little to do with the wheels)
Void
BAU BAU
- 9,813
- 11,730
Every one of us that gets this problem already understands that. That's why it is a hypothetical problem. No one is going to build any kind of treadmill under a full-sized plane, let alone one long enough for it to actually take off...but if they DID, it most certainly would take off as we have described it. That's why it is called a *mental* exercise.
Tuco
I got Tuco'd!
- 47,386
- 80,809
Did you not see the mythbuster's "treadmill"? Because they did just that. And they found a pilot who didn't think the plane would take off and he ate crow as soon as he landed.
Kuro
Naxxramas 1.0 Raider
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Void
BAU BAU
- 9,813
- 11,730
No, I've never actually watched it because I always knew it would take off, given the correct real-world applications of the theories. I guess I need to watch it, because if they built a huge treadmill, well that would be impressive on its own.
EDIT: Ok watched it, not the treadmill I was expecting, but got the job done. I would say the one thing they lacked was a more clear portrayal of the surface being pulled by the truck. It makes sense and everyone knows it was being pulled, but you couldn't really tell. They should have painted numbers on it or something so you could see it whipping by a fixed point on the ground. That's about all I can think of to make that test perfect.
Cybsled
Naxxramas 1.0 Raider
- 17,087
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Let us move past this dumb argument and look at this cool stuff: Brain to Brain interface!
http://www.bbc.co.uk/news/science-environment-21604005
http://www.bbc.co.uk/news/science-environment-21604005
Tuco
I got Tuco'd!
- 47,386
- 80,809
Pretty cool. I doubt we'll ever use a brain to brain interface over verbal or written communication though. I'm no neurologist but it seems like it'd take a tremendous change in the human brain in order to quickly encode and decode messages sent via wire.
Still, any kind of 'automatic' input to the brain is an exciting topic.