JUNKERS G.38

Junkers G.38 probably the first serious attempt to make an airplane capable to cross the Atlantic carrying with a number of passengers ever carried before.
Its creator; Hugo Junkers, a German businessman owner of an aircraft factory ho tried many times before this challenge. was made in 1929 developed of an earlier design called J-40 made for the German air army. Even though anyone else before did it he was convinced of its project and after many problems like the idea of the German air army to do one which could be used also in the air and the water, he bet per this G.38 which only couldn't land in water. It was a very risky bet cause the German air army was going to support economically the project. 
the Junkers G.38 was built with duralumin. Its wings made with a multitubular crossbar also of duralumin. They carried four useful engines responsible for carrying the sum of, at least 16800kg the weight in the vacuum. The tail like in many other planes consisted of two symmetric parts to rest the strength of the aerodynamic effect. 
This airplane was made also to rate the comers of the zeppelins, they were at the moment a very comfort transport hard to dethrone. But the G.38 did it because inside and for the passengers was the first high-class airplane, as you can see a sumptuous intent. at the same time, another impressive fact is that each wing could carry 3 passengers because in the wing root the aircraft has a height of 170cm.
Here I bring you some data taken from the internet that I think you might be interested:

General characteristics:

• Crew:  7
• Capability: 34 (D-2500/D-APIS)
• Length: 23,20 m
• Wingspan: 44 m
• Height: 7,20 m
• Aerofoil: 290 m²
• Weight in the vacuum: 16.800 kg
• Power plant:  Lineal V12 supercharged and  cooled with water Junkers L88a.
• Power: 588 kW (811 HP; 800 CV) each one.
• Propellers: four junkers wooden blades.
• Propeller diameter: 4,5 m

Performance:

• Top speed: 220 Km/h
• Cruising speed (V_c): 175 Km/h
• Autonomia: 1.950 km