Here is what I have in one of my books for the Dornier Do-18D.
Function: Longrange reconflyingboat
Crew: 4
Engines: 2X 6 cylinder Junkers Jumo 205D inline engine with 656 kW
Max. Speed: 267km/h @ 2000m
Climbrate: in 7.8 min. at 1000m
Range: 3500km
Ceiling: 4200m
Empty weight: 5980kg
Max. weight: 10795 kg
Armament: 1 13mm machine gun and 1 20 mm cannon and 2 50kg bombs
Wing span: 23,70m
Length: 19,38m
Height: 5,32m
Wingarea: 98.00m2