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Overall view of the top thrust chamber.

Note that this was a very early rocket engine; its thrust chamber is conical rather than the more familiar bell shape. It was eventually determined that a bell shape allowed the nozzle to be a good deal shorter (which saved weight) with only a minor reduction in thrust.

The V-2 and Redstone engines were conical, as were the booster engines on the Atlas A. Starting with the Atlas B, the Atlas engines (and nearly all other large engines) were bell-shaped.