Session: 01-12 Propellers and Open Rotors

Paper Number: 123719

123719 - QCSEE — Design and Test Contributions to the Rise Open Fan Program 

After the successful introduction of commercial turbofan engines with medium bypass ratios (5 – 6) by aircraft engine manufactures with products such as the CF6, JT9D and RB211 in the late sixties, NASA’s Lewis Research Center (later renamed NASA Glenn Research Center) spearheaded an aircraft propulsion development program in the early 1970’s called “Quiet Clean Short-Haul Experimental Engine” now commonly referred to as QCSEE. In addition to the goal of doubling the bypass ratio relative the early production engines, QCSEE led in pioneering (a) reversible-pitch composite fan blades, (b) a geared fan/turbine, (c) digital electronic engine controls and (d) extensive use of composites in the fan frame and nacelle. This paper reports on the design, fabrication and testing of two experimental propulsion systems for QCSEE by GE Aviation under contract from NASA in the mid-1970’s. The first concept designated as Under-the-Wing (UTW) engine, incorporated a 2.46 ratio high-speed gearbox to drive the fan with variable pitch to further improve fan efficiency along with elimination of the thrust reverser. The variable pitch fan was used for modulating forward as well as reverse thrust. This concept utilized a fan with take-off pressure ratio of 1.27 (lower tip speed) and a bypass ratio of 12. The other concept entitled as the Over-the-Wing (OTW) engine also used a 2.06 ratio high speed gearbox to drive a fixed pitch fan. The OTW engine configuration had a fan pressure ratio of 1.34 (higher tip speed) at take-off and a bypass ratio of 10. Description of three alternative fans for the QCSEE program designed, built, and tested on the component stand will be presented. Two of these fan designs were tested in engines. Variable pitch mechanism and operation are summarized in the paper. Key design features of the composite fan blade and the variable pitch mechanism are presented. The QCSEE concept was based on a lightweight, high-speed, power turbine driving a slower speed, quiet fan that required a compatible, compact, lightweight, high-power-capability, main reduction gear. Performance results of two reduction gears designed, manufactured, and rig-tested are summarized. A summary of the development of the composite frame and nacelle is presented. Limited highlights of the digital engine control are shown. Finally, overall engine aerodynamic, acoustic, and mechanical test performance are reported in this article. The impact of each of these key QCSEE technologies to existing GE/CFM products, and their contribution to CFM’s current RISE technology program will be discussed.

Presenting Author: Aspi Wadia GE Aerospace

Presenting Author Biography: Retired.
40 years in the aircraft engine industry
PhD from University of Texas
Worked at Garrett Turbine Engine Company, Phoenix, Arizona
Worked at Allison Gas Turbines, Indianapolis, Indiana
Chief Consulting Engineer - Aerodynamics, GE Aerospace (Retired), Cincinnati, Ohio (35 years)
Currently with Belcan Corporation, Cincinnati, Ohio, Chief Engineer - Aero Systems

Authors:

Aspi Wadia GE Aerospace
Jan Schilling GE Aerospace
William Solomon GE Aerospace
Gregory Steinmetz GE Aerospace
Daniel Mollmann GE Aerospace