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As an airline pilot flying Boeing 757 and 767 I think this concept is really cool but it does overlook some fundamental principles of the unreliability of weath
by esemor 9y ago
As an airline pilot flying Boeing 757 and 767 I think this concept is really cool but it does overlook some fundamental principles of the unreliability of weather in order to be practical.
This week I have landed in variable winds gusting up to 45 knots and then every inch of wingtip clerance counts, a drawback of this design.
What if the aircraft makes a long landing (floats) and suddely faces a different wind component that subjects it to a tailwind.
Also, the full circle would only be useable on zero wind days which makes me wonder about the economical reality of having a large part of the pavement be unusable most days.
- anotheryou 9y agoand conventional runways are ok with all wind? because the angle stays constant?
- esemor 9y agoYou never land with a tailwind and if the wind shifts the airport simply change the runway to the opposite one. If you use a circular runway and landing with a cross wind you would during your landing roll be subjected to a tailwind. Sure, you could stop using that part of the runway but then we're back at the practical economical argument for this design.
- EliRivers 9y ago"Sure, you could stop using that part of the runway" Would you have to stop using that part of the runway, or stop using it within a certain height? That is to say, while landing, if at that part of the runway the aircraft was already solidly on the ground would it still be a problem? Likewise taking off; if the take off point was simply well before that part of the runway, would that be fine (have to think it would be, because after taking off the plane has no reason to follow the runway - it's already gone)? If that's fine, then would you actually have to stop using that part of the runway? Could you just rotate the landing/launch points so that nobody was landing/launching at that part?
- anotheryou 9y agoGood thought, savety margins and taxi way to the next exit add even more space.
- EliRivers 9y agoWould there be taxiways to the next exit? I would have thought that a level interior ring of the runway would basically be one big circular taxiway; entrances and exits would basically be lights and markings, and planes would get directed to the appropriate entrance/exit depending on traffic, weather and the plane's own characteristics.
- rpmcmurphy 9y agoI am also a pilot. I'll add to this by explaining a couple of basic principles in flying aircraft. The #1 reason this is a very bad idea is it is not compatible with flying what's called a stabilized approach, which is fundamental to safe landings. What this means simply is you fly your last (final) leg of approach on a straight line aligned with the centerline at a shallow glide angle. The moment before touch down you reduce engine power and flare (bring the nose up) and stall the wings just above the runway. If you are flying into a crosswind, you crab (fly with the nose angled into the wind to stay on centerline), then kick out of the crab angle just prior to touchdown (you control the rudder with foot pedals). A banked circular runway is totally incompatible with this. If you misjudge your approach a bit and land long, you miss the runway. You have to go from wings level to a banked turn at exactly the right moment. Lots of potential for things to go wrong. It's just a bad, unsafe idea. Another reason this is bad, higher landing speeds. If you are flying in a banked turn, your wing will stall at a higher airspeed. Heavy aircraft already land fast, and anything that adds to that creates problems, wear on tires and brakes, etc. These people also seem to be unfamiliar with basic geometry. A "circle-ish" runway configuration would do the job while retaining long straight runways. For example, just arrange eight runways in an octagon configuration, with the airport terminal etc in the center. If you have enough land area to work with, this is easy. The problem, of course, is that land in large metro areas is expensive, so you end up with compromises such as intersecting runways as you see at airports like San Francisco (SFO). So while this may be fun as a flight simulator challenge, it is a bad, unsafe idea for the real world.
- tropo 9y agoI don't think you need to "go from wings level to a banked turn at exactly the right moment" for this. There are two ways to make it work. As proposed, the runway is banked. You bank your aircraft well above the runway surface. You fly above the runway, possibly following it as your holding pattern prior to landing. You can keep going around, banked already. When it is your time to land, you continue around in that bank and descend to the runway. Alternately, it could be unbanked with straight landings. This makes the circle considerably thicker. Landing is quite normal, aside from the runway markings. BTW, your "kick out of the crab angle just prior to touchdown" method may be standard, but it is pretty bad. The B-52 gets this right, with 4 pairs of wheels that touch the ground at the same time and are all capable of being rotated.
- exabrial 9y agoCorrect me if I'm wrong, but I thought the whole idea behind the circular part was so that doing a crosswind landing would be "easier", because you could setup the landing so the crosswind pushes your towards the center...