Why not have a curved runway?

It is common in floatplanes to takeoff in a slight turn, lifting onto one float, and turning into the wind too if possible. Sometimes it’s necessary in a small lake. Landing a floatplane in a turn is less easy.

There were serious proposals to construct not only curved but fully circular runways, e.g. here:

https://www.nlr.org/news/the-endless-runway/

Google “circular runway” and a lot of articles debating this will come up.

Imho, it should be doable for GA aircraft, but the proposals were for CAT and I have a hard time imagining this to work.

I’m not sure just how realistic a circular runway is. Could you take off and land on one? Of course. However there are other considerations which would also apply to a curved runway to an extent.

I know one of the pluses of the circular runway was being able to take off and land into wind every time – but how does this work in practice? It is not just so relevant for a light single engine GA type which takes off and lands in <500m, but if you have a 2000m takeoff/landing run, how do you define start and end points? Where do you want your headwind to be? Mid roll? Threshold? Rotation? What about Vmcg? Do you have enough control authority to lose the outboard engine and now not as before keep straight, but keep a turn towards the live side to stay on the paved surface? What about obstacle clearance on the departure end? What is the departure end? That’s going to end up being a fairly massive obstacle survey to cover all the possibilities. How would the departure be decided? We estimate getting airborne on the 310 track, what happens if we are early or late?

I am very unconvinced.

For light GA though, curved isn’t really a problem as long as it isn’t too extreme. I think Ashcroft airfield as a slightly curved runway. Worth having a Google, as their website is a bit… different.

With P-factor takeoff need a well bent runway

I vaguely remember reading an article about a proposed circular runway in an old pop-science magazine, roughly from late 1960s.

Pirho wrote:

I am very unconvinced.

So am I. I guess tyre manufacturers would love the idea… it would enhance their business heftily.

You just can’t work out the reciprocal ends in your head

I think that airport is one way only like Courchevel. The question is how fast can a plane accelerate through a flat turn? Does it really help the plane to accelerate better? It was told many years ago that accelerating on a short runway with a turn will not help, better push back the plane and then accelerate in a straight line. Or the curved part of that runway has to be banked…

Landing in a turn is a useful skill to have in the bag.

With regards using a turn to gain speed before the turn, I think it is marginal either way, the advantage of keeping moving as the power comes up is that you’re less likely to pull rubbish into the prop than standing on the brakes and winding it up.

Landing straight on a straight runway, immediately after a turn, is NOT landing in a turn, on a curved runway.
Landing in continuous S-turns on a tarred runway must be easy, as many first attempt or out-of-practice Jodel pilots use it.