05/31/2011. The Hamburger Flugzeugbau was the aircraft deparment of the Blohm & Voss shipyards, hence the 'Ha' in the designation. The first prototype Ha 138 V1 (D-ARAK) first flew July 15, 1937, the second (D-AMOR) a few months later having a number of hull changes and an increase in the vertical tail projecting below the tailboom. After considerable flight testing discovering inadequate stability, poor hydrodynamics and weak hull construction the company decided to abondon work on the third prototype.
A complete redesign retained only the basic configuration and had a
new and much larger hull. In process of the redesigning, the name
Hamburger Flugzeugbau was dropped and the designation changed to Bv
138. The first of 6 pre-production aircraft, Bv 138 A-01 (D-ADJE c/n 148) flew
for the first time in February 1939, it was later coded TW+BC.