When we first became interested in improving the Cheyenne’s performance, we focused our attention on the cowlings. First, our aeronautical engineers analyzed the existing cowling system and identified the areas that needed improvement. Then we designed a new multicomponent air pressure recovery system combining; (1) a newly designed cowling inlet repositioned to maximize the recovery of the ram air velocity from the propeller, (2) computer designed aerodynamic inlet ducting to minimize air separation and flow losses, (3) fore and aft variable air flow deflectors and a fixed inlet turning vane which function together to direct and minimize flow losses in icing conditions, and (4) a positive air pressure seal system designed to prevent leakage.
As a result of this new design, the amount of ram recovery dramatically increases in cruise, climb and during icing conditions. TAS is increased up to 15 knots without increasing engine ITT’s. The aircraft’s critical altitude is increased approximately 3,000 feet with additional torque maintained throughout the remaining climb to altitude, resulting in reduced time to climb. In addition, performance is significantly increased during flight into visible moisture with ice doors deployed.