The first Messerschmitt Me-155 design (Source: Messerschmitt "O-Nine" Gallery)

The designation 155 was used for a number of very different designs intended for a number for very different purposes.

As originally conceived in 1942 , the Me-155 was intended as a carrier fighter as a replacement of the Me-109T which was based on the Me-109E. This coincided with the resumption of the work on the carrier Graf Zeppelin which had been suspended for two years. In order to proceed quickly the Me-155 used many components of the Me-109G. The fuselage was a G-1 fuselage but fitted with an arrester hook and attachment points for a catapult. The wing was a new design however. The aircraft was to have been powered by the DB 605A engine and armed with three MG 151's and two MG 131's. Delay in the construction of the Graf Zeppelin meant that construction of the prototype was delayed indefinitely. Construction of the Graf Zeppelin was abandoned in 1943.

Messerschmitt Me-155A (Source: Messerschmitt "O-Nine" Gallery)

At the end of 1942 Messerschmitt tried to adapt the Me-155 design to a new RLM specification. This adaptation, the Me-155A, was designed as a high speed tactical bomber carrying a single 1000kg bomb under the fuselage. In this design all carrier equipment was removed and a tall tail wheel was envisaged to give enough ground clearance for the bomb. This design was rejected by the RLM however.

Messerschmitt Me-155B-1 (Source: Messerschmitt "O-Nine" Gallery)

In December 1942 Messerschmitt was requested by the RLM to submit a design for a high altitude interceptor. Messerschmitt again reworked the Me-155 design, this time into the Me-155B-1. This was powered by the DB 628 engine and armed with three MG 151. After the flight tests of the DB 628 in May 1943 in the Me-109 V-50 the RLM decided that the DB 628 was not yet ready for production and asked Messerschmitt to rework the Me-155B to utilize the DB 603A with a TKL 15 supercharger. This redesign resulted in the Me-155B-1a with a larger fuselage to house the supercharger. By now the design showed very little similarity to the original Me-155.

In 1943 the RLM concluded that Messerschmitt had to many projects on his hands and decided that the further design and development of the Me-155 should be handed over to Blohm & Voss. This meant that the design was renamed BV-155

Messerschmitt Me-155B-1a (Source: Messerschmitt "O-Nine" Gallery)