So, I watched "The Wind Rises" not too long ago, and during the film, the prototype [is showed](Caproni Ca.60), but just like the article said, it failed.
Now, is there any other recorded used of three fixed wings like this thing? Why Caproni even used three, and not the usual two wings?
There have been plenty of tri-plane designs. The famous Red Baron, Manfred von Richthofen, flew a Fokker tri-plane in the early part of 1917. However, the plane you are asking about is much more than a tri-plane. It has three sets of tri-plane wings, for nine wings total. It also was powered by eight motors, with a combined power of 3,000 horse power. The wings were attached to a flying boat hull that had 100 seats for passengers. It was supposed to be the prototype of the first Trans-Atlantic airliner.
It was an abject failure. It could only lift off of Lake Gardo to an altitude of 18 meters and it crashed on its first and only test flight. Caproni knew it was underpowered and added the third set of wings amid ship to give the plane more lift. However, it just did not have enough power to be successful. Planes as large as the Caproni Ca60 needed to have aero motors that could produce more than 750 horsepower to be successful. As it was, the Caproni Ca 60 could not generate enough lift to climb over the hills that surround Lake Gardo.
Source: "The World's Worst Airplanes" by Bill Yenne