Wow, there are so many reasons this is a terrible idea.
1. It doesn't actually solve the problem it sets out to solve (crosswind landings). To the contrary, a circular runway guarantees that if you have any wind at all then you will have a crosswind at some point in the landing. Not only that, but the apparent wind direction will be constantly shifting during the landing, making the landing even more difficult than a normal crosswind landing.
2. Flying in a circle at a low airspeed and at low altitude is absolutely the single most dangerous thing you can do in an airplane. When you are flying in a circle, the outboard wing is moving faster than the inboard wing, and so if you are flying close to stall speed the inboard wing will stall first, resulting in a spin. It is possible to recover from a spin but you have to descend in order to do it. If the spin starts at low altitude there is nowhere to descend to, so you will crash. Spins on approach to landing are one of the leading causes of fatal crashes in small general aviation aircraft.
3. Airport approach and departure procedures are designed around the fact that runways are aligned in particular directions.
4 a rolled plane to match banking will move sideway in the direction of the lower wing. to correct that the plane will need to touch down pointing outward the circle, then quickly steer to correct
Edit
5 optimal banking changes with speed and all plane takeoff and land differently. More to the point while accellerating for takeoff the plane will literally go everywhere but in the runway direction
The circular runway is banked so I would assume crosswinds aren't as devastating due to this banking. However, I am curious as to why you so adamantly believe that circular banked runways guarantee crosswinds. Is this based on scientific research that have proven this or is this just a guess?
Well that's interesting. They seem to be arguing that the bank angle is super high, causing the planes to pull massive Gs just to land or take off, and that's terrible.
Even if it's true all that means is,
(a) planes achieving takeoff instantly have better than stall speed in the open air and can safely get up and away from the city,
(b) planes landing can come in at any angle, have infinite space to negotiate a decent landing and no specific window to hit as far as retaining enough runway, plus the landing speed is significantly higher than stall speed in free air. That directly improves the controllability of the aircraft.
The guy's right, this would work just fine. Even without a bank and increased G forces, it's not a bad idea, but when you include the reality of the banking increasing takeoff/landing speed over normal stall speed, it becomes a slam dunk. Very good idea anywhere you can afford to build three or more runways in your airport.
A lot of idiots on that forum. "Hey, in just two minutes of casual thinking about this, I've identified a flaw which a professional working on this for years has been unable to see!"
Um, yeah, not so much. The concept may have problems, but that's not how it'll be debunked.
For fixed-wing drone airports, I feel like you'd have better luck making an inclined runway for landings, and a railgun-assisted runway for takeoff. Given that the biggest challenge is finding clearance at both ends of the run way, it would be nice not to have to find 360° clearance for both takeoff and landing.
How would a circular runway affect inbound emergency aircrafts?
My intuition tells me that a straight runway would be less burdensome on the flight crew. You set up for your approach then you can go back to dealing with the issues at hand.
Okay only slightly related, I had an idea a long while ago for putting satellites into orbit where you just fling them? I didn't think it good for humans because of the G but for stuff. The win being that the power required is all on earth and you don't have to carry fuel with the payload. You could spin them up on a centrifuge and then let go at just the right time (and angle). I was going to mention it to Elon one day...
The main limitations are surviving the hypersonic launch and short trip through the atmosphere, and you still need a second stage to get into a stable orbit. Your launch vehicle would basically be an upwards-travelling meteor.
Considerably more viable on the moon; lunar escape velocity is "only" 2.38km/s and there's no atmosphere. There's lots of 70s moonbase concept art depicting the use of rail launchers to return mined material to earth. Although I'm not sure it would be economically viable even if the moon were made of solid platinum.
that works well on the moon because there isn't an atmosphere to speak of but on the earth trying to accellerate to 26km/hr at sea level is both very energy intensive, and the vehicle experiences intense heating due to the atmosphere. Atmospheric drag makes this idea impractical for pretty much anything.
You know I've been researching the very same idea. And guess what none of the math I've tried so far rules it out!
You do need a very big cable though. Think miles.
There are actually many promising technologies to get mass into space with much lower marginal cost. I think the problem is that they all have high capital costs and no one wants to take the risk on a new technology.
Most commercial aviation airports (Class-B and Class C) separate commercial and general aviation traffic. The landing speed difference along (let along the camber as you suggested) make it impossible to stagger 7x7 traffic with general aviation traffic.
[+] [-] lisper|9 years ago|reply
1. It doesn't actually solve the problem it sets out to solve (crosswind landings). To the contrary, a circular runway guarantees that if you have any wind at all then you will have a crosswind at some point in the landing. Not only that, but the apparent wind direction will be constantly shifting during the landing, making the landing even more difficult than a normal crosswind landing.
2. Flying in a circle at a low airspeed and at low altitude is absolutely the single most dangerous thing you can do in an airplane. When you are flying in a circle, the outboard wing is moving faster than the inboard wing, and so if you are flying close to stall speed the inboard wing will stall first, resulting in a spin. It is possible to recover from a spin but you have to descend in order to do it. If the spin starts at low altitude there is nowhere to descend to, so you will crash. Spins on approach to landing are one of the leading causes of fatal crashes in small general aviation aircraft.
3. Airport approach and departure procedures are designed around the fact that runways are aligned in particular directions.
[+] [-] LoSboccacc|9 years ago|reply
Edit 5 optimal banking changes with speed and all plane takeoff and land differently. More to the point while accellerating for takeoff the plane will literally go everywhere but in the runway direction
[+] [-] bitmapbrother|9 years ago|reply
[+] [-] ouid|9 years ago|reply
[+] [-] yock|9 years ago|reply
[+] [-] bitmapbrother|9 years ago|reply
[+] [-] handedness|9 years ago|reply
[+] [-] Nrsolis|9 years ago|reply
http://www.airliners.net/forum/viewtopic.php?t=1357935#p1941...
[+] [-] Applejinx|9 years ago|reply
Even if it's true all that means is,
(a) planes achieving takeoff instantly have better than stall speed in the open air and can safely get up and away from the city,
(b) planes landing can come in at any angle, have infinite space to negotiate a decent landing and no specific window to hit as far as retaining enough runway, plus the landing speed is significantly higher than stall speed in free air. That directly improves the controllability of the aircraft.
The guy's right, this would work just fine. Even without a bank and increased G forces, it's not a bad idea, but when you include the reality of the banking increasing takeoff/landing speed over normal stall speed, it becomes a slam dunk. Very good idea anywhere you can afford to build three or more runways in your airport.
[+] [-] nkoren|9 years ago|reply
Um, yeah, not so much. The concept may have problems, but that's not how it'll be debunked.
[+] [-] yock|9 years ago|reply
radius is 3500m velocity is 82m/s
82^2/3500 ~ 1.92
atan(1.92/9.81) ~ 0.19 or 10 degrees of bank.
Where have I gone wrong?
[+] [-] strathmeyer|9 years ago|reply
[+] [-] gayprogrammer|9 years ago|reply
[+] [-] saycheese|9 years ago|reply
[1] http://paleofuture.gizmodo.com/these-circular-runways-were-d...
[+] [-] dingaling|9 years ago|reply
It rested on a dolly secured by a cable to the central post and whirled around until take-off.
I think a couple of installations were built but most customers chose a more conventional rocket-boosted dolly for straight runways.
[+] [-] microcolonel|9 years ago|reply
[+] [-] cadab|9 years ago|reply
[+] [-] mrfusion|9 years ago|reply
[+] [-] nayuki|9 years ago|reply
[+] [-] jason_wang|9 years ago|reply
My intuition tells me that a straight runway would be less burdensome on the flight crew. You set up for your approach then you can go back to dealing with the issues at hand.
[+] [-] nthcolumn|9 years ago|reply
[+] [-] pjc50|9 years ago|reply
The main limitations are surviving the hypersonic launch and short trip through the atmosphere, and you still need a second stage to get into a stable orbit. Your launch vehicle would basically be an upwards-travelling meteor.
Considerably more viable on the moon; lunar escape velocity is "only" 2.38km/s and there's no atmosphere. There's lots of 70s moonbase concept art depicting the use of rail launchers to return mined material to earth. Although I'm not sure it would be economically viable even if the moon were made of solid platinum.
[+] [-] avian|9 years ago|reply
https://en.wikipedia.org/wiki/Space_gun
[+] [-] binarymax|9 years ago|reply
https://www.kickstarter.com/projects/391496725/the-slingatro...
It didn't get backing but was a fun idea!
[+] [-] ChuckMcM|9 years ago|reply
[+] [-] mrfusion|9 years ago|reply
You do need a very big cable though. Think miles.
There are actually many promising technologies to get mass into space with much lower marginal cost. I think the problem is that they all have high capital costs and no one wants to take the risk on a new technology.
[+] [-] nkoren|9 years ago|reply
[+] [-] atonse|9 years ago|reply
[+] [-] hirundo|9 years ago|reply
[+] [-] jason_wang|9 years ago|reply