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.
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.
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.
What you describe needlessly adds complication to the approach, which adds risk, which will certainly result in accidents and fatalities. It's just a bad idea, and there is a reason airport designers never considered this (it is not as if the idea of banked curved roadways is new).
Sorry as a pilot, I can say this is not just a bad idea, it is a lethally bad idea. A fun simulator challenge, but not something that will work in the real world. If you are doubtful, I would suggest you try circling around a point in IFR conditions within 50' lateral tolerance above a circular runway. Be sure to add zero visibility and a 10-20 knot cross wind to simulate doing so in the clouds above the runway as you descend.
With a circular approach to a circular runway, aren't all winds cross winds (and, also, headwinds and tailwinds)?
All I'll say is if I was the head of the programming committee for the air transport association conference, I would invite the designer to keynote, as comic relief.
Even if they do, I don't see why it can't be done with an awareness system like the F-35 helmet. That would let you see the outline of the runway through arbitrary fog.
There is no special "rejected landing turn". You rise up just a bit, keep following the runway, and retry when you wish.
Because automated systems fail.
> Even if they do, I don't see why it can't be done with an awareness system like the F-35 helmet.
Because most aircraft aren't F-35s and expenses and fallible systems that are appropriate and sensible for combat aircraft that may have to operate in conditions in which civilian aviation would not aren't necessarily something you want to make civilian aviation dependent on in conditions in which, with sensible things like straight runways, it would not be.
Because a human driving the plane has a vested interest in surviving the landing.
A person who writes buggy landing software, or an operator "piloting" it from the ground can get another job if they fail.
This sort of thing works for planes too.
That might produce other problems for landing, though.
There can be pretty severe shear at different altitudes on the way down, and the wind can flip direction any time it wants.
Sure, you could stop using that part of the runway but then we're back at the practical economical argument for this design.
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?
That's such an eloquent way of highlighting the need for conceptualisation in engineering but also the struggle to convince others (investors perhaps) that you're not a complete nutcase when you think outside the box.
Just because something was thought to be ridiculous in the past and now we know better, that doesn't mean that your seemingly ridiculous idea is just as misunderstood and underestimated as that other idea was at the time.
We're already trying to build a space elevator when we don't even know what material can possibly withstand those forces. It's something over the horizon, but we're hopeful we'll find it. Likewise, powered flight was possible, the only problem was finding lighter, stronger materials for the airframe and a lighter, more powerful engine to fly it.
Frankly, the circular design isn't ambitious enough, as initially proposed.
Then slow down the disk enough to allow taxiing toward the center exit drain.
Look at Boston for example. I wonder if they take the opportunity cost of having an airport there into the cost of flying? That land could be worth 100 billion??
One interesting data point in that regard is Berlin's Tempelhof Airport (which you might remember from Indiana Jones 3). It's extremely central because it was one of the first commercial airports and was shut down a few years ago.
It's a park now and will probably remain–the plan to build even a few houses was killed by a referendum. It's also a really fascinating place, because it feels entirely unlike a normal park. There are very few trees, so it's much more open. The runways remain unchanged, and it's quite an experience to jog there, with all the history that place has seen always on your mind. (https://firstname.lastname@example.org,13.3994616,3a,75y,279...)
It's too early to tell if experiments like Lilium are successful (http://www.theverge.com/2017/4/20/15369850/lilium-jet-flying...) but that could completely upend the entire aviation industry if proven more cost-effective.
Things are conventional because they tend to work well. And part of working well is being resilient to errors and non-optimal situations.