Thursday, March 30, 2017

Circular Runways?

It's an idea, I guess, to build airports with circular runways.  The innovator says that it has several advantages over a straight runway.

I remember studying the history of flight in high school.  Early airfields were just that, large flat, grassy areas where the pilot could determine the best azimuth for takeoff or landing.  The airplanes weren't restricted to narrow, straight, concrete strips.  Circular runways would certainly mitigate the risks of crosswind landings.

I'm no aviator, and the infrastructure costs would be huge, but if you're planning to build your own airport, maybe you should consider a circular runway.


Flugelman said...

I wonder about the ATC headaches when getting away from the old rectangular pattern standards. Where do you initiate your approach? Who has precedence in the pattern in a no-wind condition? What are the missed approach parameters? Methinks the FAA would be in a tizzy.

raven said...

As if cross winds from a constant vector aren't bad enough.
As if runways that have dips and waves aren't bad enough.

Is this the same guy who decided solar panels on a road made sense?

Grumpy OldMan said...

I'm not sure what he has been inhaling, but he really needs to stop it. Instead of preventing crosswind landings, it's going to make every landing that is not in still wind conditions end up being a crosswind landing in at least part of the landing. Maybe you'll intersect the circular runway at a tangent so that you only have a headwind, but as you flare, you are traveling further down this runway which means that your heading is also going to be changing (since you're going in a *circle*) and as such, you're going to start getting a bit of a crosswind with the amount of crosswind increasing as you continue around the circle. As you make it 1/4 of the way around the circle, you will have a direct 90 degree crosswind.

On, and let's not forget what is going to happen if the runway has some ice or the aircraft hydroplanes. With current straight runways, the airplane will most likely continue on in a straight line which has plenty of concrete in that path. With a circular runway, he's still going to be continuing in a straight line, but there won't be any runway. I'm a pilot and even though I only fly a small private plane, I think this idea would be a major headache for any pilots coming into such an airport. *Maybe* round-a-bouts are an acceptable idea for cars, but I really don't think they are a good idea for aircraft.

Ruth said...

It'd take up more physical space too. If you've ever looked at how many airports are shoe-horned into cities, there's a minimum of space for the runways. Circular runways would expand the space needed.

Grumpy OldMan said...

It's not that the airports are "shoe-horned into cities", but rather that the airports are created in areas where there is a lot of empty land, but once the airport gets there, other things (residences and businesses) start growing up around it. And, of course, those people (i.e idiots) who move into the houses next to the airport soon start complaining about the noise and expect the airport to limit operations.

With straight runways, if a plane lands slightly long, it is not a major issue as long as the runway is long enough for it to stop. With a circular runway, landing long would require the pilot to be flaring for a landing while also in a bank, trying to intersect the curving runway. From a safety standpoint, I just do not think it is a good idea. A 3.5 km diameter will mean a total circumference of about 11 km (6.83 miles). So, let's use LGA as an example of the shortest runway you would want to build for commercial airline traffic (and many pilots complain about LGA being too short). LGA's runways are about 7000 ft long. For the same amount of concrete that you can build the circular runway, you could build over 5 of LGA's straight runways. All in all, I think a circular runway is not a very good idea.