How is varying levels of thrust achieved in the propulsion system?

Varying levels of thrust in the propulsion system are primarily achieved by changing the propeller pitch. The T-6 aircraft utilizes a constant-speed propeller, which means that the propeller can adjust its blade angle to maintain a specific rotational speed while varying the thrust output. When the pitch of the propeller blades is increased, the blades bite into the air more aggressively, generating more thrust. Conversely, by decreasing the pitch, the blades have a less aggressive bite, leading to reduced thrust. This mechanism allows pilots to optimize performance across different flight conditions and achieve the desired thrust without necessarily increasing engine speed.

While adjusting fuel flow does affect engine power output and ultimate thrust levels, it does not directly control the thrust delivered through the propeller in the way that changing the propeller pitch does. Therefore, changing propeller pitch is the most direct and efficient method of varying thrust in the T-6 propulsion system.