Now, with his comrades listening intently, Franz revealed the engine’s secret flaw. He told them the engine’s fan blades were made from inferior metals that could not resist heat the way they should. Germany could no longer access minerals like cobalt and nickel to make strong blades. If a pilot throttled forward too quickly, heat would build in the engine and melt the blades. “It won’t always kill you,” Franz said. “It will kill the next guy.”
