Circles - what a great idea

[Nick]

Perhaps the fuselage could be curved left or right which would determine whether it needed to land clockwise or anti-clockwise, this could also aid aircraft to follow Great Circle routes worldwide.

😂

[Nick]

Well I won't be diverted. You are all sceptical but you never know..! If the idea is there the 'how' will follow. If fuel is no longer liquid?  People on planes will no longer drink from glasses?  You lot simply have no vision!  There was I thinking you were all really clever clogs!

😝, I spend half my life at airports, if it was in any way a reality I would know about it. 😉

[Barry]

Perhaps the fuselage could be curved left or right which would determine whether it needed to land clockwise or anti-clockwise, this could also aid aircraft to follow Great Circle routes worldwide.

[T00ts]

Well I won't be diverted. You are all sceptical but you never know..! If the idea is there the 'how' will follow. If fuel is no longer liquid?  People on planes will no longer drink from glasses?  You lot simply have no vision!  There was I thinking you were all really clever clogs!

[Nick]

A planeload of chavs on their way to Benidorm would not be impressed with that. Might spill their Cherry Bs or upset their extra curricular activities in the conveniences.

And the engines tend to get starved of oil. 😉

[Nick]

Many innovative ideas are good ones, but I can't see that circular runways fall into this category.

Re the competing theories about how planes fly, I thought that both theories had been known to be correct for a long time and planes fly because of a combination of the two. The angle of the wing deflects air downwards, increasing pressure under the wing AND the curved upper surface reduces pressure above the wing, causing lift.

The article says that a plane with a flat wing can still fly, and indeed planes can fly upside down. But I'm not sure a plane with a flat wing that is also mounted level would fly unless the whole plane flies at an angle.

A plane with a flat wing can fly in a straight line using a combination of flaps and elevators. Also add in the fuselage using the area rule.
This is exactly the same for flying upside down.

[Barry]

and indeed planes can fly upside down

A planeload of chavs on their way to Benidorm would not be impressed with that. Might spill their Cherry Bs or upset their extra curricular activities in the conveniences.

[HDQQ]

Many innovative ideas are good ones, but I can't see that circular runways fall into this category.

Re the competing theories about how planes fly, I thought that both theories had been known to be correct for a long time and planes fly because of a combination of the two. The angle of the wing deflects air downwards, increasing pressure under the wing AND the curved upper surface reduces pressure above the wing, causing lift.

The article says that a plane with a flat wing can still fly, and indeed planes can fly upside down. But I'm not sure a plane with a flat wing that is also mounted level would fly unless the whole plane flies at an angle.

[Borg Refinery]

Some guy who was an engineer posted this elsewhere:

https://www.scientificamerican.com/article/no-one-can-explain-why-planes-stay-in-the-air/

I just thought it may hold some interest for some... my head isn't screwed on well enough to reread it again right now.

[T00ts]

Sorry T00ts, it's never going to happen. It's just the rambling of a madman.
LHR already has a plane land or take off every 45 seconds as it is, that's excluding the mad science.

Oh don't burst my bubble. 

[Nick]

Isn't this a fab innovation? Imagine how it would change airports and runways. Can the engineers, blue sky thinkers and boffins on here see it working?

I've thought of one potential problem. Drivers living at Milton Keynes apparently wear their tyres unevenly constantly going around all those awful roundabouts. Are planes built to go around bends at speed? I do think it looks beautiful.

https://www.dailymail.co.uk/news/article-9050845/Could-CIRCULAR-runways-Aerospace-tests-circle-designs-increase-capacity.html

Sorry T00ts, it's never going to happen. It's just the rambling of a madman.
LHR already has a plane land or take off every 45 seconds as it is, that's excluding the mad science.

[T00ts]

Admittedly, I've only ever played flight simulators (although they were marked for their attention to detail) with poor graphics, but I am told by folks who really have flown - and who enjoy the games - that it's 1% as hard as the real thing. And you should try landing one of those things on a straight runway in a good flight sim, if that's only 1% as tough as the real thing then I don't imagine landing on a circular runway, at night, in dangerous conditions is going to be much fun, but hey I could be wrong. We will see if and how it pans out (no pun intended).

I should imagine the camber would be absolutely crucial, but something is telling me in most circumstances it would make it easier.

[Borg Refinery]

An expert:

https://www.google.com/amp/s/www.businessinsider.com/why-the-circular-runway-concept-wouldnt-work-2017-3%3famp


Phil Derner Jr., NYC Aviation
Mar 26, 2017, 12:00 PM

Why the circular runway concept wouldn't work
NYC Aviation attribution logo
Phil Derner Jr., NYC Aviation
Mar 26, 2017, 12:00 PM
   
circular runway
Screenshot/BBC
I honestly thought it was a joke at first. It raised so many questions and concerns in my mind that I thought it was a satirical piece in The Onion.


But alas... This video has been going viral, even among those that do not follow the aviation industry.

To learn that the Netherlands Aerospace Centre has been researching a circular runway for years with government funding, I must concede that they may have answers and solutions to my below issues that were not provided in the short BBC report.


Netherlands Aerospace Centre
The researcher behind the circular runway concept does his research at the Netherlands Aerospace Centre. Screenshot/BBC
Though I can see why this idea may sound appealing, I feel that the moment that conditions are not absolutely ideal in that best-case bubble, the concept collapses, opening up the probability of delays, and the possibility of an increase in accidents.
It is worth noting, however, that circular runways are not a new concept.


Today, any airport can be referred to with the technical term of "aerodrome," but in the early days of aviation it specifically referenced airports that had large round runways.

circular runway
The runway concept seen in the BBC video. Screenshot/BBC
Not a turning, perimeter runway, but instead comprised of a giant circle that allowed aircraft to land straight and flat, in any direction across the middle of the circular field. This, of course, would occupy an absurd amount of space at modern commercial airports.
Banked Runway Issues
This designer says the aircraft can land at a slower speed, which I don't see as necessarily safe. Wings will generate the most efficient lift when level to the ground, perpendicular to the demands of gravity. Any rolling or banking affects that, increasing the stall speed of the aircraft, making it more dangerous to fly slower.

banked runway
The runway in the circular concept is banked. Screenshot/BBC
This is concerning when planning for the event of engine loss during takeoff, which is a part of pre-flight calculations before every single departure. An aircraft already working hard to climb in this scenario would now be faced with getting away from the runway at a bank angle that is not generating its most efficient lift. Though you could conceivably let it land right back down on that same runway, sudden thrust differential on a banked and curving runway adds two variables to stopping the ailing aircraft.
This is not to mention that you may have other aircraft on other sections of this perpetual runway that this aircraft would now be encroaching on. That means that what would otherwise be a well-practiced and non-issue engine loss instead receives more possible contributing factors to an accident.

Another big concern to me is traction.


For every single flight, a large variety of factors is calculated to determine braking distance, and one of the more important ones is "contamination," referencing precipitation or moisture that is on the runway.

A runway that is wet, even without standing water, increases stopping distance, as does patchy snow, compacted snow, ice and all of the different variables we consider. The centrifugal force they advertise would lose effect as the aircraft slows, further killing traction.

Now imagine something remotely slippery, on a slanted runway. An aircraft trying to stop on a sideways slide that must also slowly turn down pavement that's curving as well. How many runway excursions would be caused by aircraft sliding off of the edge during winter operations?

Curved Runway Issues
Aside from the curve affecting stopping on a contaminated runway, I have a concern about the curve making it difficult for the aircraft to even touch down on the centerline. While almost every landing is safe, not all landings are perfect.


It is not uncommon for flights to get down to the runway and float some feet above the surface for a little, captured in what is called "ground effect."

runway
No landing is perfect. Screenshot/BBC
On a curved runway, while the pilot is trying to comfortably plant the wheels down (while in a bank above the slanted runway, mind you), the centerline of the curved runway will be drifting off-center to its side, now adding the need to also turn the aircraft to the pilot's workload.
This level of challenge is the airline equivalent of landing on an aircraft carrier.

Navigation Issues
A claimed big selling point of the circular runway theory is that, because an aircraft can land anywhere in the circle, they can always land into the wind, ending the need to battle crosswind landings.

"Anywhere in the circle" becomes a challenge when considering how the aircraft will navigate to that specific, ever-changing touchdown zone.


Unless visibility and cloud cover is wonderful, having precision guidance systems and visual aid lighting in place is vital to a safe (and delay-free) operation. With this new runway, how would that equipment be moved and adjusted, possibly flight by flight or hour by hour as winds change, to that moving landing zone?

Airspace Issues
When it comes to airspace, the two biggest "selling points" of the circular runway are being able to operate into the wind and also allowing 3 aircraft to land at once, brings about tremendous contradiction.

First, if wind is anything less than calm or very light, there is no way that 3 aircraft can land simultaneously in different areas of the circular runway if you are trying to avoid crosswind.

airspace
Screenshot/BBC
If attempted, though one may be lined up nicely into the wind, the other 2 would then be landing with crosswind, with 1 of those experiencing both a crosswind and a tailwind (tailwinds are usually not permitted when over 10 knots). This makes this giant stretch of round pavement a single runway operation in any singnificant wind. So, congratulations, your extra special runway just took on an arrival rate worse than Newark.
Second, and more importantly to me in terms of safety, what about go-arounds?


What if 3 airliners are landing, something goes wrong and they abort landings. Their prescribed go around procedure would likely take them dangerously close to the other aircraft also trying to land or go around themselves in more congested airspace than conventional runways with a parallel approach.

And yes, multiple go arounds at once can and do happen, as Murphy demands.

Too good to be true
Keep in mind that one of the main motivations behind this is for it to be a solution to "tricky" crosswind landings.

This is confusing to me, because aside from my feeling the idea doesn't even do that effectively because of new threats it brings to the table, crosswind landings are not the safety threat that sensationalized headlines would make you believe. Though wind can and does cause delays at certain airports, crosswind landings have not caused an epidemic of accidents, or even small amount of fatalities in recent times by any measure.


Crosswind landings look scary for sure, but they are example of skilled airmanship that you should be in awe of, not frightful of. Clearly defined crosswind limitations and the ability to easily execute a go around if an approach becomes unstable are why air travel is as incredibly safe as it is.

Those videos are examples of aviation safety working effectively.

Websites that post videos of "wild," "scary," and "frightening" crosswind landings are clickbait. The creator of the circular runway concept even admits that he was "inspired by watching scary crosswind landings on YouTube," not from any challenge or need that the aviation industry is actually facing.

See the vids in the article; like he says it sounds equiv to landing on an aircraft carrier.. ah the fond memories of going 'splashoo' in F/A-18 Korea attempting that, twas highly difficult.

[Borg Refinery]

Admittedly, I've only ever played flight simulators (although they were marked for their attention to detail) with poor graphics, but I am told by folks who really have flown - and who enjoy the games - that it's 1% as hard as the real thing. And you should try landing one of those things on a straight runway in a good flight sim, if that's only 1% as tough as the real thing then I don't imagine landing on a circular runway, at night, in dangerous conditions is going to be much fun, but hey I could be wrong. We will see if and how it pans out (no pun intended).

[T00ts]

April the 1st come early?

Science from the daily mail. Just saying is all..

Two stick in the muds then. I think it's a lovely idea.