A six-engined inverted sesquiplane the Caproni Ca.90 was designed as a heavy bomber and first flew in 1929. It had two tandem pairs of 1,000 hp (746 kW) Isotta-Fraschini Asso 1000 W-18 inline piston engines mounted above the lower wing, each pair drove a four-bladed pusher and a two-bladed tractor propeller. Another pair of engines was mounted above the fuselage. Only one Ca.90 was built.
Although the Dornier Do X flying boat that flew later in 1929 had a larger wingspan and weight it remained the largest landplane until the arrival of the Tupolev ANT-20 in 1934.