The Hamburger Flugzeugbau Ha 135 was the first aircraft produced by the new aircraft subsidiary of the German company Blohm & Voss.
The two-seat biplane manufactured by the Hamburger Flugzeugbau subsidiary of Blohm & Voss was a means of giving the company experience in making modern metal components for civil and military aircraft. It was developed as a trainer for the German Ministry of Aviation. After it proved unsuccessful in this role, the company sold it as a sport aircraft.[1]
The first prototype, designated the Ha 135 V1 (company production number 101, registration D-EXIL), made its first flight on 28 April 1934. After the company used it for flight development with a BMW-Bramo Sh 14A engine installed, the German Air Sports Association flew it as a sport aircraft.[1]
The second prototype, designated the Ha 135 V2 (company production number 102, registration D-EKEN), made its first flight on 30 April 1934. The Hamburger Flugzeugbau used it for flight characteristics and performance tests beginning on 14 July 1934. It also later flew as a sport aircraft with the German Air Sports Association.[1]
Hamburger Flugzeugbau manufactured four more Ha 135s before production ceased.[1]