11–20 of 44 posts
Opposite Opinion: REALITY CHECK: CIRCULAR RUNWAYS http://theavion.com/reality-check-circular-runways/
Earlier quoted context omitted.
and conventional runways are ok with all wind? because the angle stays constant?
You 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.
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?
> If someone one hundred years ago would have said that we would be transporting as many passengers in aircraft as we would in trains, people may have thought , "a steam engine would never fit in an aircraft made of wood and ropes". 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 w…
Earlier quoted context omitted.
You 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.
"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…
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 compo…
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.
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??
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 compo…
Under one of the original articles, in the comments section some military pilot pointed that lateral forces on big airliner on this runway would break the fuselage and gear of the plane. I'm disappointed that this argument wasn't addressed in todays article.
Given a radius of a curve and bank angle it is simple to calculate what the minimum required speed is to have 0 lateral force
Earlier quoted context omitted.
"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…
Good thought, savety margins and taxi way to the next exit add even more space.