Inspired by the take off catapult postings: If an airport were to be built in a natural bowl or valley, the runways could be arranged so that aircraft can approach on the downhill side, touch down somewhere near the bottom and slow down on the uphill side with less need for brakes & reverse thrust (which are ineffecient and stressful to the airframe). Takeoff is assisted by the initial downhill acceleration, followed by the uphill section, acting as a much less aggressive version of the ramps used on aircraft carriers.

The airport would look like a giant skate park, with terminal buildings at each and of the runway, or a perimiter track around the top of the valley, local topography permitting.
-- Twizz, Nov 19 2009

To properly represent a skate park, should there not also be a giant pipe or half-pipe and a ramp or 'grinding rail'?
-- hippo, Nov 19 2009


...and the pilots would have to wear jeans, hanging down behind their knees.
-- shudderprose, Nov 19 2009


...and instead of "Welcome to London Heathrow airport, where the local time is 7:47" they'd say "Woah! Gnarly landing!!"...
-- hippo, Nov 19 2009


You are going to need the mother of all drainage systems, and clean outs. I don't even want to think about snow loads.
-- 2 fries shy of a happy meal, Nov 19 2009


The landings are going to be a bugger. The pilot would have to touch down exactly at the right place, or hit either the rim of the bowl or the up-sloping far side.

I learned to fly in my dad's Cessna 150 off a grass strip that had a slope at one end. That end was lower than the middle of the runway, not higher, and was really handy. One day I kept messing up my approach to the flat end of the runway, so I circled around and landed on the upslope, easy-peasy, by just flying nearly flat until the hill came up for me. For take-offs, when the wind required it, we'd taxi down to the bottom of the hill and come snarling up the slope, then lift off on the flat middle portion.

The other strip we had available was almost all on a slope, with a little flat area at bottom and top. Everybody took off downhill and landed uphill.

I'd build an airport on a big dome, but not in a big dish.
-- baconbrain, Nov 19 2009


I learned to fly in a Swallow motorglider, also on a domed grass airfield. The high lift and light weight of the motorglider combined with the extra windspeed over the hill often made it difficult to get the aircraft down at all, it wanted to float on right over the hill.

I had envisaged the 'bowl' airport built in a natural horseshoe valley, possibly modified with some additional earthworks. Drainage would be by the natural means, i.e. a river which would run under the runway at the bottom of the valley.

Rather than sharp 'lips' at the top, the runway would curve smoothly to horizontal.

When landing, the approach angle is maintained slightly steeper than the runway angle, so no flare out required and no period when the aircraft is close to stall and difficult to control.

Touchdown may be anywhere on the downhill section of the runway. On reaching the bottom, full flap may be used again to slow the aircraft without the risk of going light on the wheels and losing the steering stability provided by the tyres.

The whole experience places less stress on the airframe and passengers, as the force vectors are closer to those experienced in normal flight.
-- Twizz, Nov 20 2009



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