Circular Runways

[Shpaget]

Wind is important, especially if there are obstacles in the vicinity and the direction of the runway.

Flaps are quite tricky beasts and climb rates are quite affected by them.

Edited April 4, 2017 by Shpaget

[Exploro]

On 4/1/2017 at 0:25 PM, Shpaget said:

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

Other than "poorly"...

One could fly a DME arc into or out from the runway environment. The only problem of course would be the vertical guidance down to the runway environment in the case of landing. Further I would find establishing routes to clear terrain and other obstacles another incredibly difficult challenge to surmount.

[kerbiloid]

Airport Maelstrom

[YNM]

On 4/4/2017 at 8:32 PM, 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).

Well, you can always make planes fly without flaps, but the roll out distance will be too far than the specification. (for all reasons this shall never happen IRL, but sometimes while playing FSX or so I forgot that, and the plane would just nicely hit some buildings the opposite side of the runway...)

Fighter planes aren't normally equipped with flaps/slats (some do). Standard commercial airplanes would need specifications from the manufacturer, but again, for a lot of reasons it's better to have some flaps down than none - you can just have some 1.5 km runway instead of a 3 km runway for example.

But as @Shpaget mentioned - you need to really take into account the details of what's on your path. It's why to land on London City airport they have to make a permit for usage of certain aircrafts - maybe some movements would have to be done in a way different than standard guide (like, I don't know, flaps 10 instead of the specification's 20 and fast climb to ensure clearing the highrises ?)

If anything fixed, flaps helps you to keep a different AoA than without, so you can be in slow landing descent and not stalling while still able to see the runway...

14 hours ago, Exploro said:

One could fly a DME arc into or out from the runway environment. The only problem of course would be the vertical guidance down to the runway environment in the case of landing. Further I would find establishing routes to clear terrain and other obstacles another incredibly difficult challenge to surmount.

The conditions they're simulating it in is all standard, if not optimistic. Real world are way harsher than what they've simulated I suppose.

Edited April 6, 2017 by YNM

[Ketatrypt]

On 3/29/2017 at 10:39 AM, YNM said:

As I've saw this surfaced up in another forum I'm member of (surprised to see this comes on here late !) I'll just "repost" :

It's an Amsterdamer, what do you expect ?

Fair amount of problems :

- On straight runways, the aircraft doesn't experience changes in wind heading during takeoff / landing rollout. On circular one, they will.

- On straight runways, pilots have clear cues to take. How'd they do it on a circular one ?

- Performance is still limited to 1 (at most 2, but I'm sniffing tenerife^2 there) aircraft landing / takeoff simultaneously - you want to be upwind during descent / ascent.

- Tangentially sloped landing surface ? Sounds fishy...

- What about "IFR is foggy" ? How'd they do the ILS/Localizer ? I bet they haven't simulated in heavy gust there !

- Surrounding environment restrictions - I mean, airports today suffer from glideslope obstacle restrictions or noise restrictions. Their circular runways will suffer from the same problem, unless you want crosswind approach to a circular runway !

Having Kai Tak / Isafjordur approach is still more feasible than having to use the rudder pedal just to keep yourself going around a runway !

 Absolutely agree. Just way to many points of failure to be realistic.

It would be much more efficient to just use the same area and make a few straight runaways. A curved runway would be particularly challenging to program navigation around. By nature, a circle has an infinite amount of vertices. Even if you were to break it down into 1/2 degree increments (which is a very wide angle in context of aircraft navigation) that would mean that the runway would need over 700 different radio beacons, and someone (or something) would have to change the nav modes as they passed by (about 1 beacon for every 130m of runway, or, at a landing speed of 300km/h, one beacon every second and a half.. If even 1 beacon were to fail, the plane would likely careen off the runway)  Even with 2017 tech we have issues with predicting localized weather phenomena that may interfere with the conventional straight in glideslope. Add those complications in with the complications that come with landing on a curved slope, where the inside wing will be prone to stalling.. Just no thanks. There is just not enough built in failsafe. If you mess up on this sort of runway, its a huge messup. Even something as simple as a blown tire would be hugely amplified on a curved/sloped runway. 

Edited April 13, 2017 by Ketatrypt

[0111narwhalz]

But if it's curved and sloped just so, you can't tell that it's either.

[sevenperforce]

45 minutes ago, 0111narwhalz said:

But if it's curved and sloped just so, you can't tell that it's either.

Only for a specific speed. While you're still on the ground. 

[kerbiloid]

A flightplan will include a choice:
Plane type:
[  ] Clockwise
[X] Counterclockwise

Advanced idea: eight-shaped runway. It allows to change the turn direction right on the runway,

[p1t1o]

Pictured: a better airport design