Which technology helps increase exhaust velocity by retaining heat within the primaries?

• A. Thermal Barrier
• B. Pipe Length
• C. Formed
• D. Tri-Y

Answer: (A)

Retaining heat in the hot primary section keeps the exhaust gases hotter, so they carry more energy into the expansion that produces thrust. A thermal barrier provides insulation on the primary surfaces, reducing heat loss to surrounding parts and allowing the combustion products to stay hotter longer. That sustained high temperature translates into higher exhaust velocity as the gases expand, boosting performance. Other options describe exhaust-path configurations that affect flow and backpressure rather than directly keeping heat in the primaries to raise gas temperature.