Strategic Technical Aerospace Resources LLC

Power Conversion

Experience the seamless transition from traditional piston-powered aircraft to state-of-the-art electric propulsion systems with our Electric Power Conversion service.

Energy Efficiency

Maximize your aircraftʼs performance with our Energy Efficiency service, designed to optimize power usage and reduce fuel consumption, while enhancing the overall sustainability of your aircraft.

Future-Proofing

The Mark-15 PSRU: High-Power Propeller Reduction Gearbox

1. Overview:
   • The Mark-15 was a high-capacity PSRU designed by EPI Inc. for aircraft engines.
   • Its primary purpose was to efficiently reduce the output revolutions per minute (rpm) from the higher input rpm of the engine, allowing it to drive propellers within the desired speed range.
   • The Mark-15 achieved this through geared reduction, making it an essential component in aircraft propulsion systems.
2. Key Features:
   • Torque Handling: The Mark-15 could handle input torques of up to 1600 lb-ft while maintaining safety margins.
   • Bulletproof Reputation: Users often described the predecessor, the Mark-9 PSRU, as “bulletproof.” The Mark-15 drew heavily from the success of the Mark-9.
   • Vibration Absorption Technology: It incorporated refined vibration absorption technology, which had proven effective in applications like NASCAR, INDY-CAR, and military systems.
   • Improved Gearing Design: The Mark-15 featured enhanced gearing design for optimal performance.
   • Cost-Effective Housing: EPI Inc. designed a less expensive housing for the Mark-15, making it easier to machine and assemble.
   • Single-Mesh and Two-Mesh Versions: The Mark-15 was available in both single-mesh and two-mesh configurations.
3. Historical Context:
   • EPI Inc. completed the design and analysis of the Mark-15 gearbox in 2009.
   • The prototype system was under development, including critical components like heat-treated housing castings.
   • However, EPI temporarily put the manufacturing of the M-15 prototype on hold to prioritize other projects.
   • Eventually, the intellectual property and all tooling and parts inventory for the Mark-15 were sold to a client working on a custom V-12 engine design.
   • This client produced a limited number of Mark-15 gearboxes.
   • Subsequently, the rights to the Mark-15 were acquired by AeroSport Engineering A/S, a European company, which now serves as the source for Mark-15 gearboxes globally¹².

In summary, the Mark-15 PSRU played a crucial role in optimizing aircraft engine performance, ensuring safe and efficient flight. Its legacy lives on through its robust design and impact on aviation technology!