Reviving this thread, I flew to the relatively recent airfield in Solheim/Frosta (the previous Frosta airfield has been moved there) and it has a curved runway which also has a slope, makes it a bit more interesting :-)
Landed up hill before and managed to follow the curve without even really thinking about it. Since there was almost no wind, we took off the opposite direction, downhill. During take off, I did have to notice the turning felt a bit less ‘automatic’ than on landing, but not particularly problematic either…
Silvaire wrote:
Once upon a time (1933)
He he, that was a really round airfield 
Found a picture of ENVA also from 1933. Some of the aircraft are F.F.9 Kaje, built at Kjeller. Don’t know what the larger ones are. The houses and hangars on that picture, the whole field and some of the town (my home town), were bombed to pieces by RAF bombers at the very start of the war. The exact same day bombers from Luftwaffe bombed an army facility just 10 km east of the airport. A perfect coalition attack 
4 days later, the German forces took ENVA and started rebuilding and building runways.
I learned to fly in 1964 at Thruxton, which had hard runways and taxiways, but enough grass for us to land and take off according to the signal square T. Crosswind was trained, as a deliberate exercise regardless of wind direction.
The taildraggers avoided tarmac, that was for complex aircraft with tailwheels and brakes.
Once upon a time (1933) at the birthplace of US Naval aviation…
Ibra wrote:
It’s only when the rest of the world introduced “1D runways” that the Brits/Canadians had to teach crosswind landings and their pilots, they took ages to go solo, to solve this problem RAF/RCAF introduced their famous “3 triangle grass runways”
I think this was pretty standard Luftwaffe configuration also. This is ENVA anno 1955. In 1940 the airfield was only a grass field, then the Germans came. They changed to hard runways sometime during 1940 and 1945. Still the same in 1955.
Today only the E/W strip is left although the original configuration clearly can be seen.
Sorry guys to spoil the party, the problem of circular runways has been fully solved by RAF/RCAF, their first airfields were plain big grass “2D surfaces” with one single windsock in the middle, you fly the Spit/T6 overhead, check the windsock and land into wind
It’s only when the rest of the world introduced “1D runways” that the Brits/Canadians had to teach crosswind landings and their pilots, they took ages to go solo, to solve this problem RAF/RCAF introduced their famous “3 triangle grass runways” but Brits kept that tradition of overhead joins
For practical purposes, “3 triangle grass 1D runways” is a nice approximation for the circular runway, some believe this works better than the “2 cross-runways solution”…
https://www.quora.com/Why-do-most-RAF-airfields-have-a-triangular-runway-configuration
Graham wrote:
I am not going to do the mathematics to work out how wide it would have to be to a give a 1,000m straight run
I’ll bite. 333m, assuming the diameter is measured centreline to centreline.
A 3km diameter circular runway gives you 9.4km distance before you are back where you started.
To get a comfortable 1,000m run (for light/medium GA) you would change direction by a little under 45 degrees over the course of that run and use slightly less than 1/8 of the whole circle.
If the runway is of significant width then you can cut the corner, going ‘out-in-out’ like a racing car, which would reduce your directional change and if it were sufficiently wide then you could accomplish it in a completely straight line, or something so close to a straight line that it became irrelevant.
I am not going to do the mathematics to work out how wide it would have to be to a give a 1,000m straight run, but by this point surely you might as well create a square airfield/runway and operate in any direction, like they used to!
There is one in Essex, NE of North Weald, actually more like a boomerang
We are al sort of negative! Let’s pull that into a positive spirit!
I’d fully support that all airports are rapidly switched to circular runways! Let’s do a global internet campaign on that!
Why? It would finally bring back to life one of my most favorite airplanes, the Bae-146 “Jumbolino”! As it is obvious that 2 engine jets would be a very bad idea on circular runways (as they would need hangar-gate size stabilizers to compensate loss of outbound engine at V1), we will se many cool new designs of 4 engine small jets ;-)
