Large-scale advanced propfan (LAP) program progress report

Abstract

The propfan concept, which has been the subject of much research since the mid 1970's, is an advanced propeller concept which maintains the high efficiencies traditionally associated with conventional propellers at the higher aircraft cruise speeds associated with jet transports. The Large-scale Advanced Propfan (LAP) program extends the research done on 2 ft diameter propfan models to a 9 ft diameter article which is representative of the size and construction that would eventually be installed on a new aircraft. This program includes design, fabrication, and testing of both an eight bladed, 9 ft diameter propfan, designated SR-7L, and a 2 ft diameter aeroelastically scaled model, SR-7A. The LAP program is complemented by another NASA sponsored program, the Propfan Test Assessment (PTA) program, which takes the large-scale propfan (developed under the LAP program) and mates it with a gas generator and gearbox to form a propfan propulsion system and then flight tests this system on the wing of a Gulfstream II testbed aircraft. This paper is declared a work of the U.S. Government and therefore is in the public domain.