Navy internally cooled recuperator (ICR)

Heat exchanger to preheat incoming air using stack gases on oil-fired surface ships, intended to raise cruise efficiency from ~10% to 30%, eliminating off-station refueling time. First built version lasted two minutes before tearing itself apart from transient thermal stresses. Eagar served on a Blue Ribbon panel investigating it.

This was ten years after that, and there have been some improvements in quality control in the mills, in understanding of the heat treatment and the water treatment, and in calculation of stresses. In some of the videos you're going to hear about the Navy's internally cooled recuperator on the surface ships, and how originally it was supposed to — this is just a big heat exchanger, take the stack gases from the oil-fired ships and preheat the incoming air so you get more efficiency. When you're just cruising along, a nice lazy stroll through the Pacific, you're operating at about ten percent efficiency because most of your heat's just going up the stack. You're not at full battle speed.