You might have seen a concept video of a circular runway going viral on social media. This new radical airport concept was proposed by Dutch Engineer Henk Hesselink of the Netherlands Aerospace Centre under The Endless Runway Project. Check out his research paper here. Henk proposed to construct a circular runway with a diameter of approximately 3.5 km around an airport terminal.
Such an airport would take up only a third of the space of a conventional airport. Moreover, aircraft will be able to take off and land independently of the direction of the wind. The aircraft could be routed away from residential areas during take-off and landing. Finally, multiple aircraft can use the endless runway at the same time resulting in increased airport capacity.
This futuristic airport concept indeed looks spectacular on paper and in concept videos but can the endless runway be the future of aviation? Let’s dive deep into some technical aspects surrounding aviation to understand if the Endless Runway Concept will take off?
Obstacle Clearance Area in the direction of landing & take-off
Traditional runways are straight because, in the landing and take-off direction, there has to be an obstacle clearance area. With circular runways, the clearance area has to be the same for each of the 360 degrees around the airport. If the obstacle clearance area is not the same, there will have to be different performance calculations for each degree.
Problems with Aircraft Handling after an Engine Failure
With circular runways, there would be an extreme problem with aircraft handling if one of the engines fails just after taking-off. This is on account of the centrifugal force due to circular motion and the fact that the working engine will turn the aircraft towards the dead engine. It will get extremely difficult for the pilots to have the aircraft under control if such a situation arises.
Speeding Aircraft on a Slippery Circular Runway
Aircraft on wet and slippery circular runways at speeds over 300 km/hr will certainly not be any pilot’s dream. Slippery circular runways will not be safe for landing and take-off that makes them unusable during rainy, snowy, and stormy weather conditions. There will be more chances of the wing-tip hitting the circular runway if it is wet and slippery.
Wing-Tip clearance on account of Banking
Since the outer edge of the circular runway will be banked, the aircraft will face the issue of the wing-tip clearance. With the banked character of the runway, the wingtips and engines will be closer to the ground than currently is the case. Pilots will need automated support for take-off and landing on banked circular runways due to reduced wing-tip clearance.
Moreover, on account of the banked runway, an aircraft will need to land faster than its normal speed to avoid stalling the aircraft.
Changes in Holding Patterns of Adjacent Airports
If one airport switches to a circular runway, then the neighboring airports have to change their holding patterns. Moreover, they will need to switch to circular runways too.
In short, the circular runway is just a futuristic concept, and I don’t see it being implemented in the future.