Circular Runways

[mikegarrison]

It's somebody's fever dream. Classic case of people solving the wrong problem, worrying about crosswind instead of visual references, runoff safety, parallel capacity, etc.

[p1t1o]

I say they just concrete over a 10km x 10km square and just tell pilots to "fit on it".

The terminal, hangars and gates would be underground, and to depart, planes would be elevated on a lift into the centre of the square. "Just take off somehow".

Cuts down on air traffic control costs + complexity, you get all the benefits of no crosswind/optimum headwind, no problems with weird camber or steering on takeoff/landing runs.

There are literally no downsides as long as pilots keep their head on a swivel, which they do already. Might be useful to fit planes with horns. The beep-beep kind, not the stab-stab kind. Although...

[benzman]

On 3/31/2017 at 3:11 AM, p1t1o said:

I say they just concrete over a 10km x 10km square and just tell pilots to "fit on it".

The terminal, hangars and gates would be underground, and to depart, planes would be elevated on a lift into the centre of the square. "Just take off somehow".

Cuts down on air traffic control costs + complexity, you get all the benefits of no crosswind/optimum headwind, no problems with weird camber or steering on takeoff/landing runs.

There are literally no downsides as long as pilots keep their head on a swivel, which they do already. Might be useful to fit planes with horns. The beep-beep kind, not the stab-stab kind. Although...

This reminds me of a WW2 Catalina flying boat base over here called Lake Boga.  You can find it on google earth.  The lake is almost a perfect circle, so all takeoffs and landings could be made directly into wind.

 

[Nibb31]

That's how airfields used to be pre-WW2: a big flat field with no marked runways and a big sign with the name of the airfield. 

Just land in the direction of the windsock and try not to hit another plane.

Edited March 31, 2017 by Nibb31

[LordFerret]

Am I landing in London or New York ..... and then disaster.

[Green Baron]

2 hours ago, Nibb31 said:

 

Just land in the direction of the windsock

??

I hope you mean the opposite direction ...

Edited March 31, 2017 by Green Baron

[magnemoe]

2 hours ago, Nibb31 said:

That's how airfields used to be pre-WW2: a big flat field with no marked runways and a big sign with the name of the airfield. 

Just land in the direction of the windsock and try not to hit another plane.

During WW2 they found that launching and landing an huge number of planes required some coordination

 

[YNM]

On 3/30/2017 at 11:11 PM, p1t1o said:

I say they just concrete over a 10km x 10km square and just tell pilots to "fit on it".

Dry lakebeds. Maybe that's what they're really testing nowadays, not some secret flying contraption anymore.

[Nibb31]

This is what Berlin Tempelhof Airfield looked like during WW2:

The planes would follow the semi-circular taxiway and just take off in whatever direction suited them best.

Edited April 1, 2017 by Nibb31

[Green Baron]

Yeah, an airfield.

I mean, this is all very interesting, but the modern idea of a huge circular runway tries to address different problems than those of the 30s and 40s. Like traffic volume, separation and spacing, crosswind, noise reduction, space usage in metropolitan areas, handling in terminals and so on.

Besides the first hasty reactions and a few nonsense posts on this, i personally don't think it is realizable at all (right now), but mainly because many of the established procedures, standards and the related technology like approach and departure, navigation and landing aids had to be redone.

If i take into account how impossible it seems to switch to digital radio in air traffic ...

 

Edited April 1, 2017 by Green Baron

[Shpaget]

So, any ideas on how the ILS would work on it?

Other than "poorly"...

[Green Baron]

I don't think it would, can't imagine how. Microwave landing system wouldn't work either. They are all designed for a fixed threshold. One would need something much more flexible, that could project the threshold anywhere on the circle and that for multiple approaches on curved courses. Byebye ILS, you served us well ...

Also approaches and departures are based on fixed paths (it was 15 years ago, that still so ?), VORs or NDBs show the way. Holding patterns are designed for one way in and one way out. These also had to be rethought. I could imagine some futuristic installations on ground as well as in the aircraft that could calculate the paths for incoming and leaving traffic and transmit it to the pilots via projection or vr. Train the crews for that ...

Or (and i already hear you all shouting) kick out the crew and let the computer do it. It's not my idea :-)

Edit: the concept paper linked above says that such procedures have to be defined, but by 2050 technology should be able to transmit and present all necessary data to the crew in an appropriate way (p. 19).

 

 

Edited April 1, 2017 by Green Baron

[Shpaget]

Yeah, they still use SIDs (Standard Instrument Departure Route) and STARs (Standard Arrival Route) that are usually based on some radio equipment, but it doesn't need to be with with todays tech.

Anyway, AI would have no trouble flying any reasonable 3D pattern and satnav is more than capable of providing positioning, which is why modern autopilots do it on regular basis. Autopilots control the aircraft most of the time.

[Green Baron]

There are more mind boggling design proposals: the runway, 150m wide, could have a flat inner part and an increasing bank angle to the outside so that aircraft can choose their paths on take off and landing depending on conditions and what they want to expose the passengers to.

I can well imagine that operating this kind of design needs a precision that to handle should better be left to machines.

If it is a joke then a very thoughtful one. And less ridiculous than Musk's idea of "resistance is futile .." :-)

 

Edited April 1, 2017 by Green Baron

[YNM]

17 hours ago, Shpaget said:

Yeah, they still use SIDs (Standard Instrument Departure Route) and STARs (Standard Arrival Route) that are usually based on some radio equipment, but it doesn't need to be with with todays tech.

Some SID and STARS allows for usage of RNAV (ie. GPS / LORAN (?)) directly already, and at least, that's what most people in flight sims do. But not sure IRL - maaybe pilots prefer only AP during cruise ?

EDIT : to note, SIDs and STARSs are way better than vectors to final or localizer or so. They exist because it's an improvement.

17 hours ago, Green Baron said:

Or (and i already hear you all shouting) kick out the crew and let the computer do it. It's not my idea :-)

Well, as planes are mostly hydraulic - mechanic, I sort of asks the inherent faults of such systems... I mean, so far we only have elevators, automated trains and people movers on the list of commercial fully autonomous vehicles, those things generally don't endanger their occupants in faults (well not elevators maybe but there's no way to stop if that accident happens in any way). Planes however...

Edited April 2, 2017 by YNM

[magnemoe]

Problem with idea is first as someone pointed out you have dominant wind directions, 

This is why you tend to have an one or two runways in dominating direction, perhaps one H arrangement 
Now if you wanted better cross wind capacity you could make the I cross runway into an X if you had it do double duty as taxiway under normal wind conditions. 

This would take far less space and be more flexible than the circular idea and you would keep an higher capacity in primary wind directions 

[WestAir]

"Don't worry, the runway is inclined to prevent excessive G forces!"

Great. As if kicking the rudder at the last second wasn't enough, now I have to roll the plane!

I'm calling the union. Every landing on a circular runway should earn me an additional 3 flight hours pay above my monthly guarantee.

[wumpus]

9 hours ago, WestAir said:

"Don't worry, the runway is inclined to prevent excessive G forces!"

Great. As if kicking the rudder at the last second wasn't enough, now I have to roll the plane!

I'm calling the union. Every landing on a circular runway should earn me an additional 3 flight hours pay above my monthly guarantee.

I'm assuming that building such a thing for local airports would require such a tight radius to make things difficult for part-time pilots (the idea has been suitably trashed for big regional/international airports).  [kerbal mode on]How about a mountaintop?  Airline hubs might not be so popular anymore, but consider a "two mile high [~3km]" airport/hub.  Since gaining altitude consumes the most fuel, building a circular runway around a mountain top might make more sense.  Things might get complicated if you don't have room to park many planes, and have a fairly small airport at that.[/kerbal]

Edited April 2, 2017 by wumpus
kerbal tags

[Mad Rocket Scientist]

On 4/2/2017 at 8:28 AM, wumpus said:

I'm assuming that building such a thing for local airports would require such a tight radius to make things difficult for part-time pilots (the idea has been suitably trashed for big regional/international airports).  [kerbal mode on]How about a mountaintop?  Airline hubs might not be so popular anymore, but consider a "two mile high [~3km]" airport/hub.  Since gaining altitude consumes the most fuel, building a circular runway around a mountain top might make more sense.  Things might get complicated if you don't have room to park many planes, and have a fairly small airport at that.[/kerbal]

Ooh, and you could use smaller engines on the planes because you could take off downhill, then slowly climb to cruising altitude.

[Shpaget]

Planes have plenty of power for takeoff.

Airliners with two engines must be capable of taking off with only one.

[WestAir]

2 hours ago, Shpaget said:

Planes have plenty of power for takeoff.

Airliners with two engines must be capable of taking off with only one.

Sort of. I doubt you'll be controllable if you were sitting still then went for take of power on just one engine. 

[YNM]

2 hours ago, Shpaget said:

Planes have plenty of power for takeoff.

Airliners with two engines must be capable of taking off with only one.

At those points where an engine fails and you have to takeoff, your plane should flop off the runway easily. Before that you're advised to slam the brakes. It's not power, it's velocity. The interesting bits are how fast can you climb, which is where the constraints comes from. (hint : quite easy, V1 is fairly below Vrot and V2 is way above Vrot.)

EDIT : some planes do have to get their flaps extended to take off, if you wonder.

Edited April 4, 2017 by YNM

[wumpus]

3 hours ago, YNM said:

EDIT : some planes do have to get their flaps extended to take off, if you wonder.

Er, does that mean that some planes *don't* need their flaps extended?  I suppose an F-15 (and anything with thrust>weight) could simply muscle its way into the air, but I'd expect few others (maybe crop dusters).

[ment18]

How important is wind?  I would think that it doesn't really matter considering the size of airliners and their high speed and that we currently use straight runways in only a few directions.  It seems much more useful as a way to put a much larger number of runways in a smaller space, at which point it might be much easier to use an octagon instead of a circle.  Don't have to curve the edges of the runway or do any turning.

[Green Baron]

50 minutes ago, wumpus said:

Er, does that mean that some planes *don't* need their flaps extended?  I suppose an F-15 (and anything with thrust>weight) could simply muscle its way into the air, but I'd expect few others (maybe crop dusters).

Ask the flight handbook of each individual plane :-)

It's mainly a matter of speed if we ignore safety consideration like tyres, ground effects, ... If the airplane can reach the speed necessary for take off at a given weight, wind and athmopsheric conditions than it can take off without flaps.

Landings can be done with only little flap instead of full, at a higher speed and therefore more stability. This is done when it's gusty or windy for example. I am sure when you guys watch youtube videos of aircraft landing in adverse weather you will realize that many of them have the flaps only a little bit extended for landing.

Yeah, wind IS important. It's the medium the aircraft moves in. A lot of flights are redirected because of wind (weather). Aircraft have limits for tailwinds and crosswind components. On the other hand, with a strong wind on the nose an aircraft lands almost on its own ...

In the concept paper they consider aircraft types up to military bombers with a takeoff speed of 250knots.