Circular....runways?

[Gregg_Seipp 565]

http://www.bbc.com/news/magazine-39284294

It'd be cool if someone would make one for a sim for folks to try out.

[anden145 2,282]

Quite an interesting idea... Would indeed be cool to try out.
But I don't think, that the sim supports it? Can you even be considered "on the ground" while in a 'bank'?

[ubersu 78]

Originally proposed years ago (1930s) for cities with flat space issues.

DJ

[ESzczesniak 128]

From a pure calculation perspective it seems interesting, but practically it seems like quite the challenge.  How much error do you have in your touchdown zone?  And you have to match the curve precisely while flying in to touchdown.  What about wing clearance as the bank levels out to flat ground?  I suspect this is one of those things that is very efficient in computer simulations, but loses a lot of it's edge in practice. 

[anden145 2,282]

Actually I think it's quite an interesting idea. Would be fun to try out in a simulator...

If you (took the time to) read the documents about the project which is posted here, you would find, that many of the 'concerns' are actually addressed. Probably why it has received EU funding for the project as well... this is not just some crack-pot (sorry, but I've read some comments on other forums, with people lashing out *sigh*) who thought of a good idea which doesn't have any merit... Whether or not, it could be done in real-life is another question, though...

On another note, I just found a report from EuroControl, which - among other suggestions to overcome/cope with the increasing demand for air-travel and congestion at airports - have for instance multi-level runways as an example... 

Go figure... In my opinion, we need people who think outside-the-box to overcome challenges like these... 

[Chock 17,769]

31 minutes ago, Anders Gron said:

Probably why it has received EU funding for the project as well...

Funding doesn't necessarily mean they'd ever consider it: It's far more likely the reason it got funding from the EU, is that it is probably a cheap funding option for them compared to other things they could have done, not necessarily the most practical one they could pursue. Large governmental organisations such as the EU have to be seen to be addressing concerns over such things as air pollution, air traffic congestion etc, as a result, paying someone to do 'some research' means they are able to claim that they are making an effort to address such matters. Loads of 'ideas' that are never going to be pursued in a million years get government funding for that reason, and yes, it's a stupid state of affairs, but it happens.

[Zikous82 5]

How could there be a three planes simultaneously, if wind is blowing from one direction?

Milan Zikmund

[fs4fun 366]

I'm not clear how this makes x-wind landing any easier or safer. With a straight, flat runway, the pilot crabs or slips to maintain a ground track along the runway centerline, then maneuvers the plane at touchdown to align with the runway. With a banked circular runway the pilot can fly directly into the wind until reaching the touchdown target but before touchdown the plane must be banked to match the runway's bank angle and turn radius at the calculated landing speed. Even ignoring variable and/or gusting winds this doesn't sound any easier to me, would be interested to hear what r/w pilots think.

There could be loads of practical problems such as construction costs and perhaps terrain or other obstacles limiting approach paths, and what would instrument approach procedures look like? Could autoland systems that depend on level terrain for radar altimeters be made to work? 

I agree that it would be fun to try it in the sim.

[hs118 707]

All takeoffs and landing have crosswind components. Doesn't seem very safe in gusty conditions.

[RichieFly 723]

Is it April 1st?

Is 'April Fool's Day' a thing in Europe? I ask because this is the kind of thing we in the US see around April the 1st.

Circular runway? ha ha. Very funny.

[Chock 17,769]

Kerching! Hmmm.. maybe I can get funding from the EU to do some 'research' into my 'underground airport' idea...

[RichieFly 723]

I just recalled that in the 30's someone (perhaps HH) proposed a steel mesh constructed above a given city as a means of supporting air traffic without the need for airfields.

IT COULD WORK!

[Matthew Kane 1,343]

Winds was my thoughts exactly as well, Snow wouldn't be good either as harder to clear the snow and greater chance of losing control while turning. I live in the windiest city and our airport is notorious for the windy landings and go arounds, wouldn't work here but maybe in a utopia with no wind, snow rain etc etc 

Also the slanted runway looks like it has a curvature that would increase the chances of a wing strike

[188AHC 2,138]

Fairly common to use circular takeoff and landing patterns with floatplanes in the smaller lakes in Florida. Probably elsewhere too. I've witnessed it many times. Not something I would like to experience in a 7X7 type of aircraft though. I can just envision numerous wingtip strikes occurring.

 

[Chock 17,769]

My concerns would be many:

Unless the runway had a massive radius, or the wind was obligingly blowing in a curve as you tracked around it, you would either be starting off in a crosswind, or hitting one midway on your take off roll, or getting one at lift off; the notion that there'd be no crosswinds to deal with is, frankly, untrue. More to the point, where do you place an ILS antenna, or the PAPI lights, or the approach markers on a runway which has no ends? It's all very well showing a nice simulation of it, but in practical terms, transitioning from instruments to visual in a low visibility approach is danerous enough as it is without adding to matters by having to pick up a visual reference for the flare whilst also flying a curved descent. That's an accident waiting to happen.

With a normal runway, it is easy to know where to place a bird scarer vehicle, but where do you put such a safety vehicle on a curved runway?

You'd presumably have asymmetric lift on the wings on a take off roll, since the outer wing would be travelling a bit faster than the inner one, and possibly some blanking effect from the fuselage on the outer wing's inboard flaps and inner wing area. So V-speeds would need to increase, and that means tires are going to undergo far more stress and wear, as well as risking overheating.

The sideways load on the tires would not be good either. Anyone who knows anything about NASCAR will know that those racing cars have bigger tires on one side of them and a different toe-in on one side, both of which are to help counter the effects of them being in a continuous turn on a banked raceway at high speed in order to reduce the stresses from a sideways load on a tire. You'd have to do that on the aeroplanes too, and it would mean that such an aeroplane could not land safely at any other airport unless that too had the exact same curve/direction of landing on its runway too. The expense and practicality of making literally every commercial destination for an aircraft around the entire world have a circular runway of a standard radius, and modifying/designing new aeroplanes to suit such operations, is a ridiculous notion from a practical standpoint. The airlines/aircraft manufacturers didn't even want to stump up the cash for smoke hoods or to get rid of kapton wiring, yet we're to imagine they'd pay for all those modifications?

The approaches would be needlessly complex; you'd have aircraft coming in from all over the place having to cross over to one FAF whilst planes were taking off through those tracks, and whilst it sounds in principal a good idea to allow aircraft to take off in the direction of their intended flight to speed up routing, it would mean a massive change to the entire SID/airways system, not to mention being a nightmare of proximity risks for ATC.

Everyone who knows anything about aerodynamics knows that the stall speed increases in a bank, so VRef speeds would have to be higher, as would touchdown speeds, and again there's more tire wear/risks of blow outs for you. Everyone who also knows about that is aware that there are more accidents in GA aeroplanes when they make their turn onto final than in any other phase of flight, with stalls and spins at low altitude almost always proving fatal. Thus the idea of having aircraft at low speed and low altitude, in a banked turn, is, quite obviously, an accident waiting to happen. The only practical way you can alleviate issues of adverse yaw and asymmetric lift on aircraft with a long wingspan at low speeds, is to make your turns really steep at very high speed. I know this from flying gliders with a long wingspan, where I'll very often crank that thing around onto final in the kind of banked turn that makes it look like I'm trying to avoid a Messerschmitt on my tail lol (this is usually done at well over twice the level stall speed of the aircraft, then using the spoilers and AoA to kill that speed on the approach), and I whilst don't mind that personally, nor would air force pilots, no passenger is going to want their holiday jet to be pulling those kind of moves.

These are just the problems which spring to mind, I'm sure there would be many others.