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March 1982

NASA CR–3505

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NAS3–20769

128

Evaluation of Wind Tunnel Performance Testings of an Advanced 45o Swept

Eight-Bladed Propeller at Mach Numbers From 0.45 to 0.85

C. Rohrbach, F.B. Metzger, D.M. Black, and R.M. Ladden

Advanced turboprop; Prop-fan; Energy efficient; Propeller

Unclassified -Unlimited

Subject Category: 02

Hamilton Standard

Division of United Technologies

Windsor Locks, Connecticut 06096

A07

Project Manager, Robert J. Jeracki, Propulsion Systems Division, NASA Lewis Research Center, Cleveland, Ohio 44135.

The increased emphasis of fuel conservation in the world and the rapid increase in the cost of jet fuel has stimulated a

series of studies of both conventional and unconventional propulsion systems for commercial aircraft. The results of these

studies indicate that a fuel savings of 15 to 30 percent may be realized by the use of an advanced high-speed turboprop

(Prop-Fan) compared to aircraft equipped with high bypass turbofan engines of equivalent technology. The Prop-Fan

propulsion system is being investigated as part of the NASA Aircraft Energy Efficient Program. This effort includes the

wind tunnel testing of a series of 8 and 10-blade Prop-Fan models incorporating swept blades. Test results indicate

efficiency levels near the goal of 80 percent at Mach 0.8 cruise and an altitude of 10.67 km (35,000 ft). Each successive

swept model has shown improved efficiency relative to the straight blade model. The fourth model, with 45 degree swept

blades reported herein, shows a net efficiency of 78.2 at the design point with a power loading of 301 kW/m2

(37.5 SHP/D2) and a tip speed of 243.8 m/sec (800 ft/sec).