Part two of the Quest for Power series breaks down rotary and radial engines, why circular layouts solved cooling and reliability, and why they also came with nasty tradeoffs. From WWI rotaries to ...

Add Yahoo as a preferred source to see more of our stories on Google. GettyImages 528673160 Michael Cole Corbis via Getty Images 2 Powerful and dependable, the Rolls-Royce Merlin aero engine was ...