Throughout the early 1940's Thiel and his team sought to produce a single chamber 25 tonne thrust engine in place of the kludged prototype engine for the A4 that used 18 separate 1.5 tf chambers. They managed to demonstrate a 60 second burn time in the 18-chamber design, but the engine itself was considered too complicated to fabricate in production, requiring thousands of hand-assembled tubes to introduce fuel and oxidiser into the chamber. Thiel sought to replace these thousands of tubes with a simpler injection system - rows of simple bored holes on a flat injector plate at the head of the chamber. But this could not be accomplished before the A4 went into production, and the 18-chamber design was what flew in thousands of production V-2's.

German design of advanced rocket chambers for the A4 was centered at the Technical College in Dresden. The team there was led by Georg Beck, and included Karl Zinner (inventor of the "shower-head" injector), Hans Lindenberg, and Konrad Dannenberg. They shuttled between Dresden and Peenemuende during the long trial-and-error process of producing a rocket engine injector that would produce stable combusion. One design after another resulted in engines that created resonant vibrations during combusion that tore the engines apart, or uneven combusition that burned through the injector face. The team finally managed to produce the B7 injector plate for an 8-tonne thrust engine, and this was used for the Wasserfall surface-to-air-missile. It was only in 1945 that the Dresden team perfected the B8 injector plate, intended for use in the model 39a tapered head combustion chamber engine for the A4 production series C. The B8 used a circular slotted injector plate, with orifice holes arranged in complex radial, parallel and circular patterns. This design never went into production in Germany, but formed the basis for successful post-war American and French rocket engines.

• Used on stage: A-9. on launch vehicle: A9/A10.

• Used on stage: A-9. on launch vehicle: A9/A10/A11.

• Used on stage: A-9. on launch vehicle: A9/A10/A11/A12.