At what point is research just plane stupid?

[Ttaskmaster]

Umm.... helicopter?

[Xlucine]

It's worth considering how much of an issue crosswinds are for modern large passenger aircraft - i.e., a very very small one. It used to be that runways generally came in 3s, set out in a triangle - so you'd always be within 30 degrees of the prevailing wind. Here's solent airport, not quite a triangle but you get the idea:


However, as aircraft got bigger (needing bigger runways, and becoming more resistant to crosswinds), this fell out of favour and all modern airports have just one runway. Here's southampton airport for reference:


Even larger airports that need more than one runway to keep up with demand don't bother worrying about crosswinds, as this diagram of the planned heathrow expansion from the BBC shows:


The only reason you get crazy videos of planes landing in extreme crosswinds in the first place is because planes can land in extreme crosswinds easily, and it's much more economical to bring everything on one runway!

[peterb]

Umm.... helicopter?

Yes, who in their right mind would try lifting something with a rotating blade on top of it?

And lasers, what possible use could there be for pumping light into a ruby crystal just to get light out?

[MaddAussie]

They are already using giant fans in many parts of the US to increase the speed of the earth's rotation. This is why the days are shorter now. It's about stopping global warming.

I heard most of the hot air for global warming comes out of Trump...

[Gerrard]

Here's solent airport, not quite a triangle but you get the idea:

Lee-on-Solent; I used to fly gliders there when I was at Uni and was one of the examples I was thinking of regarding landing into crosswinds. There are quite a lot of old RAF stations in a similar layout.

[EndlessWaves]

Next I want to see a circular aircraft carrier

The Russians has a circular battleship. It wasn't very seaworthy.

[peterb]

Lee-on-Solent; I used to fly gliders there when I was at Uni and was one of the examples I was thinking of regarding landing into crosswinds. There are quite a lot of old RAF in a similar layout.

Except Lee-on-the-Solent was a Royal Naval Air Station - HMS Daedalus!

However all military airfields used to have a similar layout. There is an old Wartime RAF station in the New Forest. The runways have gone, but if you take a photo from the air you can see the triangular layout.

[Top_gun]

*ahem*

https://xkcd.com/123/

*cough*



You know the cartoon is plain wrong as everyone knows James Bond never dies.

[scaryjim]

"every action has an equal and opposite reaction"

Or has someone recently disproved Newton and I just missed the memo?

[Top_gun]

"every action has an equal and opposite reaction"

Or has someone recently disproved Newton and I just missed the memo?

Not at all. For example, if you swing the ball from a string in a circular motion then it's the tension in the string which gives equal and opposite reaction.

ETA: There is no such thing as centrifugal force unless you're watching fiction films or washing machine adverts.

[Jonatron]

I downloaded some FSX scenery (#141) for the Nardò Ring, which is about 4km in diameter, bigger than the 3.5km in the circular runway video.
Here's some screenshots: http://imgur.com/a/ZKJhf .
It looks very scary and difficult to land on. I didn't bother reading the research, but I would read the part about how to land on it if pointed directly to it

[wazzickle]

Next you guys will be saying there's no such thing as Coriolis force.

[DanceswithUnix]

Top tip: When not in use as an airfield, a circular runway could make the most boring track day event ever for car drivers

The Russians has a circular battleship. It wasn't very seaworthy.

Aww awesome, like some sort of Unidentified Floating Object!

I was thinking for comic effect a carrier would be shaped like a polo mint, and if it tried moving would just spin around and around, but once again real life out does me. A nice looking ironclad with maximal frontal area for people to shoot at, smooth, but respect for your navel knowledge I had no idea such a thing ever existed

[Ttaskmaster]

Yes, who in their right mind would try lifting something with a rotating blade on top of it?
And lasers, what possible use could there be for pumping light into a ruby crystal just to get light out?

I meant helicopter as in the ideal (and possibly only suitable) aircraft for circular runways... not that it was a stupid idea. I *love* the darn things!!

[scaryjim]

... if you swing the ball from a string in a circular motion then it's the tension in the string which gives equal and opposite reaction. ...

So explain how the ball causes tension if there's no force moving it away from the centre point...?

[ik9000]

Newton's laws (for general mechanics ie not quantum/atomic level stuff)

An object at rest will remain at a state of rest unless compelled to change that state by a force acting upon it
An object in motion will remain in a state of uniform linear motion unless a force acts upon it to change that state
For every action there is an equal and opposite reaction
The rate of change of momentum (ie the acceleration) of an object is directly proportional to the force acting upon that object.

The moving object would move in a linear fashion were it not for the force acting upon it, provided by the string (pendulum) or outer hoop (disc model). The change in the momentum of the object (acceleration - in this case angular) requires a force - and the two forces must oppose each other. The string or hoop imparts a force on the object compelling it to follow an angular path, the object pulls on the string/pushes on the hoop in accordance with Newton's 2nd law.

That people get their knickers in a twist over centrifugal vs centripetal is a joke to me. The point is better made that a centrifugal/petal force is not a distinct class of force such as magnetic, nuclear strong/weak force, van der waals, gravitational etc. It is simply a mechanical force (tension/compression) applied in such a way as to maintain a circular motion in an object. That the governing equations involve angular momentum and radial/tangential accelerations, etc does not change this. This is where SFAIK the pedants have a point, but I don't think it extends to trying to differentiate between centripetal vs centrifugal. It's more complicated when it's angular motion sure, eg Coriolis effects when there is a change of radius during the motion, and the like, and conservation of angular moment of momentum starts to come into things, but fundamentally it is still dealing with rates of change of momentum due to linear forces.