Re: Circular runways
Posted: Thu Mar 23, 2017 3:00 pm
@Omega: Banking+centrifugal force should do the trick and make it actually easier. About the ILS problem, two thoughts: First of all, ILS stations are already now not always on the ends of the runways, ILS uses internally actually some shifting of the positions, it appears. But on the second thought, ILS will eventually anyway become obsolete the more GPS is used for virtually everything. With ILS you can bring a plane down actually plus/minus ten feet, with GPS+software in the flight computer, you can do basically about 0.1 feet. But more important, you can do non-linear approaches anyway. Means, on airports with a mountain in the way, you can actually guide the plane over the mountain and then in the descent. So, in longer terms, ILS as we know it today will be at least for the commercial planes become a thing of the past.
@HJ1AN: 15,000ft sounds wild, I know, but the point is, if you look at big airports and you measure from the most extreme points of all runways, those airports have actually almost now often a bigger diameter, only it's not round. As I posted some days ago, I don't think, this whole idea is feasible for smaller airports anyway, but those have usually not 747s and A380s coming in. Probably not even 777s.
What I try here is actually making up my mind. I see some pros and some cons. Omega is right to be worried about pilot training ... but then, as KL-666 pointed out a hundred times, we have already now, with straight runways a lot of reasons to be worried about that. Talking Air Asia and Airbus-philosophies here. We are currently in a stage of development, one wonders, shall we bet on badly trained pilots or badly programmed computers. In my experience, people develop ideas, like those circular runways, under an implicit assumption of optimal conditions and the firm belief, everything is built like it was planned and everybody does his job right under all conditions. Which in reality is rarely the case. So I am not so much worried about planes sliding sideways over some ice spot on the runway after they stopped already. I am also not so much worried here about a touch down of 150 tons of plane on such an ice spot. Since the plane comes in slightly banked anyway, it has enough turn momentum to get over it and to be pressed into the runway again by the bankment. No, what still worries me is the idea to have a big concrete thing with tunnels under it. See, some smart guy calculates, it is no problem. A plane of 150, even 200 tons at lets say 150 knots doesn't produce enough force to cave in the tunnel with the traffic way under the runway. Then, they build it and what happens? Actually, not one plane, but some hundred per week rumble over this spot of the runway. Each of them alone is not heavy enough or fast enough to cause significant damage. Some little cracks at best. Even the occasional emergency landing at 160 knots or the occasional overloaded plane and the superheavy taking off is not a problem in itself. But after say five years and ten-thousand plane movements later, all those little cracks add up and a plane disappears in a sinkhole. A very special sinkhole because at it's bottom is a four or six lane traffic way with some hundred cars. I think, the developers of this idea have thought about planes only, not the airport infrastructure as a whole. We all remember airports in some places in the early 80s when planes got bigger and the passenger numbers soared. They extended runways, installed bigger jetways, they even built more restaurants, but it took them ten years to actually organize the passenger streams in the terminals. The circular runway idea is similarly only focused on the planes. But you end up with having a concrete ring around an airport, a ring, the people getting to the airport can't cross. So there have to be tunnels and I would really like to see the static calculations and the dynamic load calculations for those.
@HJ1AN: 15,000ft sounds wild, I know, but the point is, if you look at big airports and you measure from the most extreme points of all runways, those airports have actually almost now often a bigger diameter, only it's not round. As I posted some days ago, I don't think, this whole idea is feasible for smaller airports anyway, but those have usually not 747s and A380s coming in. Probably not even 777s.
What I try here is actually making up my mind. I see some pros and some cons. Omega is right to be worried about pilot training ... but then, as KL-666 pointed out a hundred times, we have already now, with straight runways a lot of reasons to be worried about that. Talking Air Asia and Airbus-philosophies here. We are currently in a stage of development, one wonders, shall we bet on badly trained pilots or badly programmed computers. In my experience, people develop ideas, like those circular runways, under an implicit assumption of optimal conditions and the firm belief, everything is built like it was planned and everybody does his job right under all conditions. Which in reality is rarely the case. So I am not so much worried about planes sliding sideways over some ice spot on the runway after they stopped already. I am also not so much worried here about a touch down of 150 tons of plane on such an ice spot. Since the plane comes in slightly banked anyway, it has enough turn momentum to get over it and to be pressed into the runway again by the bankment. No, what still worries me is the idea to have a big concrete thing with tunnels under it. See, some smart guy calculates, it is no problem. A plane of 150, even 200 tons at lets say 150 knots doesn't produce enough force to cave in the tunnel with the traffic way under the runway. Then, they build it and what happens? Actually, not one plane, but some hundred per week rumble over this spot of the runway. Each of them alone is not heavy enough or fast enough to cause significant damage. Some little cracks at best. Even the occasional emergency landing at 160 knots or the occasional overloaded plane and the superheavy taking off is not a problem in itself. But after say five years and ten-thousand plane movements later, all those little cracks add up and a plane disappears in a sinkhole. A very special sinkhole because at it's bottom is a four or six lane traffic way with some hundred cars. I think, the developers of this idea have thought about planes only, not the airport infrastructure as a whole. We all remember airports in some places in the early 80s when planes got bigger and the passenger numbers soared. They extended runways, installed bigger jetways, they even built more restaurants, but it took them ten years to actually organize the passenger streams in the terminals. The circular runway idea is similarly only focused on the planes. But you end up with having a concrete ring around an airport, a ring, the people getting to the airport can't cross. So there have to be tunnels and I would really like to see the static calculations and the dynamic load calculations for those.