Primarily for general aviation discussion, but other aviation topics are also welcome.
By cockney steve
#1528423
You were supposed to post on the FIRST of April, G :twisted:


Whilst we're on flights of fancy /fantasy. a scaled-up leaf-blower, of the type where a long trunking has air under pressure ,delivered to a deflector which shoots the airstream down a parallel return-path and simultaneously creates a strong vacuum where the airflow changes direction 160*.......now, mount this device so the return-stream flows along, above, a huge conveyor-belt and you have the bones of a STOL - runway-system,

Landing aircraft would enter the "return" airflow, which, you'll remember, is augmented by the venturi-effect, this airflow, directly over the "conveyor-belt" could be matched to the flying-speed of the aircraft, which would become virtually geo-stationary and settle gently on the belt.
This would overcome 2 of the major problems with the circular runway....tyre-wear , even on a banked circle, would increase dramatically. Landing-gear would also need to be dramatically strengthened,due to the centrifugal (centripetal? ) forces pressing the aircraft into the banking...In turn, a much higher takeoff speed would be needed , to overcome the centrifugal force, by generating increased lift.


Well, OK, but you started it! :oops: must get out more.
By Nick
#1528425
A very interesting analysis. The concept has been tried as the report states.

I'm sure that if they wanted to test the theory in more depth, earth banks with grass surfaces could be cheaply constructed. I bet there would be no shortage of private pilots of all and varying aircraft/abilities from microlight to lager GA types willing to take part in any trials.

I for one would be up for it.

Nick.
By cockney steve
#1531201
Lack of lateral thought, here. put the complete ring on wheels, on a circular track. Aircraft lands into- wind, track revolves into- wind direction, thus assisting braking (and the gear/ braking drag assists the rotative effort)...."clean" section of runway presented to the next into-wind lander...easy-peasy.......There are Roulette-wheel manufacturers who have plenty of building- experience, albeit on a slightly smaller scale. :wink:
By ChrisRowland
#1531214
No, the other way round.

Aircraft lands on section that is rotating forwards at it's speed. There's no braking needed, all you do is open the spoilers, taxi inwards and stop near the hub. You need not so much a rotating runway, more a rotating disk. You don't change the rotation rate, passengers, freight and supplies are managed through the hub. The speed should be low there, no different to getting on and off a moving walkway. For take off you taxi out to where the rotation speed is equal to your take off speed. Set take off power, close the spoilers and rotate.

No wear and tear on the undercarriage or brakes. Maybe no need to choose to land into wind. Aircraft with different take off or landing speeds use different disk radii.

The people to go to are the ones building fairground roundabouts, they could even arrange for it to play tunes to divert people's attention from the aircraft noise.
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By Morten
#1531228
Not quite, I fear.

There are still some basic laws of conservation of energy which will sooner or later give rise to some pretty hefty forces at play here.
After 'touchdown' you still have the same mass travelling at the same speed, albeit now on a curved track.
Unless you want to stay on the disc and spin around for ever, you would need to taxi inwards (in an equivalent crosswind to your touchdown speed - say 130knots for a 737...). If you (gently!) turn inwards you would see yourself starting to go forward on the disc and you'd need to brake (with a sideways load on the UC). Overall, the forces the UC would need to dissipate would be the same + plus the fact that you are also rotating.

But then you get to the hub... what do you do?

Unless the hub is infinitesimally small, or the radius of your disc is extremely large in proportion to that of the hub, the 'small step' between the rotating disc and the static hub will be significant. Human beings can get on and off a moving walkway because we step - less easy with a CAT behemoth travelling at tens of knots. Trying to do the 'Nightrider into truck' trick - sideways - would be interesting :-)

Getting out from the hub to your 'rotation radius' on the disc would raise the same issues but in reverse - whilst trying to dodge the poor souls who have just arrived but have not yet managed to get off the disc.

Would make for a cool display, though :-)
Its the kind of thing which Gerry Anderson would have made look cool 8)

Morten
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By Pete L
#1531246
GrahamB wrote:
Dave W wrote:..Or sequencing.


S'obvious innit.

Overhead join.


Luton used to have an overhead join for airliners, but that was in the days of Vintage Atco.