An idea from a guy in the Netherlands. He is undertaking computer testing. Wonder if it’s worthwhile. (Link is a BBC video).
I can’t see it happening any time soon (or ever). I fully admit that I don’t know much of anything about flying (and even less about landing), but it’s got to take a lot of training/retraining to land on a banked surface. I’d also be curious if it’s even possible to do with a crosswind. On a normal runway, if there’s a sudden perpendicular wind, it shoves the plane over, but it’s still on the runway. What happens here? Does one wheel hit the tarmac? Does a wingtip hit it? I’m sure all this would be tested first, I doubt I’m the first to think of it.
I’d also be curious as to if it’s economically feasible. The video said it’s the length of 3 runways but acts like 4 and will help with congestion. IIRC, O’Hare has a section with 4 overlapping runways, so they could put in this system and turn that into 5 or 6 effective runways*. But it’s not just ripping up and putting down concrete like redoing a road, it has to be built up like a race track. They’d have to land quite a few more planes each year to pay for it.
Maybe all of that is no big deal, maybe it’ll pay for itself in a few months. I really don’t know, these are just the things that popped into my head.
*I don’t fully understand what he meant by it acting like 4 runways. 3 runways can have 3 planes on them at any given time (not taking off, I know, but on the tarmac, getting ready). I’d be surprised if the FAA/local airport would allow 4 planes on this single, circular runway at the same time. Also, ISTM the time/cost savings would come show up if they could find a way to have planes landing and taking off while others were doing the same and, again, I really don’t see that happening.
Oh, and that reminds me of another thing, I didn’t look to hard, so maybe it was mentioned in the video, how big is this and are there straightaways? Or, IOW, how easy is it to deal with a plane running out of runway. Can a plane galloping along at take off speed take a banked turn? Have planes even been tested for that?
Sorry, one last thought, I wonder how this setup will handle the flyover/go-around situation. It shouldn’t make a difference, but some of those planes get pretty close to the runway before going back up, and with that, I’m curious (and assume it’s the case) there are ‘long’ parts of the circles in both NS and EW directions to deal with wind.
Yeah, lots of questions and thoughts, but it’s late, I’m rambling and that video and 'article, wasn’t much more than ‘hey, how about a circle runway dude’.
Just use a treadmill.
A turntable has fewer moving parts.
But you’ve really gotta nail that sweet spot. 
He says the idea was inspired by watching planes land in difficult crosswind situations - and that this will solve it by creating a continuous choice of landing directions, so there’s only headwind to deal with. (on its face, this sounds like it may be wrong - because flying a curved path into landing means the plane will experience a change in the relative direction of wind as it lands)
Then he goes on to explain that the continuous choice of landing directions means that environmental noise can either be fairly shared across all residential areas surrounding the airport… (which is in direct conflict with the idea above)
— or that it would offer the ability to route air traffic over less populated areas to minimise impact (which can be achieved with a straight runway - you just need to think about it before you build it.
Why not just make the runway a giant flat disc of concrete - still gives you the choice of landing direction, but without the obvious risk of landing on a curved bank, and even though a flat disc probably requires more concrete surface, it doesn’t need the engineering of a curved bank.
It’s great to dream, but this has the smell of a solution looking for a problem (as well as ignoring its own drawbacks).
More thoughts:
What would it be like in heavy rain or snow?
Isn’t it a problem that planes taking off are ready-banked in toward the centre of the circle?
The video said the ring diameter was about 3 kilometers. Assuming a speed of 150 MPH, that’s a lateral acceleration of about 0.3G. I think this would effectively preclude the use of a flat ring, but with the correct bank angle, the landing gear would see a perfectly normal (i.e. perpendicular to the tire tread surface) loading of 1.05G, i.e. just slightly above what they would experience sitting still. I expect this would be tolerable for the plane and for passengers. With a progressive bank angle from zero at the inside edge of the runway to 17 degrees at the outside edge, you could always find the right bank angle to achieve neutral steering, no matter what your speed is.
Planes can land in pretty ridiculous crosswinds, so ending up on a crosswind portion of the ring isn’t a huge deal considering the benefit of the ring is having essentially infinite runout if you have a braking problem on landing, or need to abort a takeoff right before (or even right after) you rotate.
I’m sure there are big drawbacks to a circular runway, but benefits like that certainly justify exploration in a simulator, as they are doing.
Bravo!
Regarding the noise, I don’t like that idea. I live VERY close to an airport, like within feet of it. I almost never hear planes. I also work very close to the airport (on a different side) and hear planes all day long, as do a lot of the people in that area. In fact, many of them had their houses soundproofed by the airport about 20 years ago. It seems to me that it makes more sense to keep the noise limited to very specific areas instead of spreading it all over the place.
In fact, if I mention to someone where I live, they’ll ask me about airport noise and I can honestly tell them I almost never hear it. However, back when I lived in a different house that was [checks map] about 9 miles away, I’d have to wait for planes to fly over to finish conversations. The difference being that the old house was under a flight path and my current one isn’t.
Personally, I don’t think ‘we’re going to make it suck for everyone instead of just a few people’ to be a good selling point for this.
Another thing is that the airport property would be huge. Currently, there’s crash fields* at each end of the runways. They take up a substantial amount of property that’s essentially unusable since it’s reserved for planes that land to soon or overrun the runway. With this plan, instead of a few of these properties, they’d almost have to own all the property around the airport for a few hundred feet.
Again, maybe, I don’t know, I haven’t really thought this out yet.
:dubious: I think it would be the same amount of real estate, or possibly less. Right now, runways are 8,000-12,000 feet long (1.5-2.2 miles), not including overrun zones. Altogether, for example, Detroit’s airport is about 2.9 miles x 2.9 miles. The circular runway in question would have a diameter of 3km (1.9 miles), and according to what we see in the video, it would basically define the perimeter of the airport. Moreover, it would be a circular boundary, not a square/rectangle/trapezoid, so the corners of the old airport grounds would be available for other development.
ILS (Instrument Landing System) would be a challenge to re-design.
Also, Marker Beacons.
You’d have to have predefined touch-down points at intervals around the ring, with an ILS system installed at each point.
Or maybe you just scrap ILS altogether, and go with a precision-GPS guided approach: you tell the plane’s computer where the assigned touchdown point is, and it either manages the automatic landing, or paints ILS indicators on your HUD or instrument panel.
That’s sort of what I’m saying. With airports as they currently are, at each end of all the runways there’s another few hundred feet of unused area designed for planes to crash, for whatever reason, on take off or landing. If the runway is circular, a plane coming in for a landing and over shooting the runway is going to go be on a tangent to the runway, right? Same with a plane that comes in short or one that takes off gets 100 feet in the air and nose dives, they’ll all be on a tangent. So with a regular runway we just have an open field at either end since we can take a good guess as to where it’ll be, with a circular one, ISTM, we’d need another ring around it as a crash space since the crash could happen anywhere. At least that’s how I’m picturing it.
And a big-ass bug net, even fewer.
It’s impossible to overshoot, or come in short, on a runway that has no beginning or end, so you don’t need a giant runout annulus on the outside edge of the ring. You just let your straight/tangent approach path take you in high until you fly over the point of tangency, then bank to follow the path of the runway ring and continue your descent until you touch down. You don’t need to fly low over the surrounding neighborhood and try to touch down as soon as you reach the point of tangency; touchdown could be 45, even 90 degrees away from the point where your straight-and-high approach path contacts the ring.
The video says up to 3 planes can take off and land at the same time. But wouldn’t only 1 of those planes be at the optimal angle relative to the wind??
I think the plane is supposed to spiral in towards the runway, eventually flying in a tight circle that matches the runway. I’ll leave it to the real pilots to comment on how difficult this is.
Has anyone tried this for real? If not using airliners, then perhaps fighters, or Cessna type small aircraft?
Crosswinds aren’t a problem unless they’re blowing pretty hard. A headwind during takeoff/landing is handy for reducing the length of runway used, but when your runway is basically infinite in length, it’s not a big problem if the prevailing wind manifests as a tailwind instead (for reasonable wind speeds); you just roll a little farther around the ring before rotating (or turning off to a taxiway). OTOH, if part of the ring is experiencing a 20-knot tailwind (this appears to be beyond the official limit for at least some aircraft), well, just don’t use that part of the ring today as the takeoff/touchdown point. You can still use it for starting your takeoff roll or ending your landing runout, though, since your touchdown/liftoff points will be somewhere else around the wring, at some less problematic angle relative to the wind.
Why am I seeing this in glorious over-saturated color on the cover of a Gernsback magazine?
With a large-breasted dame hanging on the stick arm of her rugged pilot BF, foreground?