NASA 1998 SBIR Phase I

PROPOSAL NUMBER: 98-1 03.01-2800A

PROJECT TITLE: A Low-Noise 3-Blade Composite Propeller for General Aviation Aircraft


The proposed innovation is a 3 blade composite propeller optimized for low noise. This will use the Quasi-Constant Speed (QCS)flexible composite propeller concept developed by Global for 2-blade propellers. The QCS propeller changes the pitch of the blades, without the complexity of existing constant speed propellers, by use of flexible composite blades that deflect to the optimum blade angle for takeoff and the optimum angle for cruise. The design of QCS propellers has been difficult since the interaction between aerodynamics, acoustics, structures, and manufacturing limits are inter-related. This has required exhaustive iterative design work by various specialists which took 6 months before all of the requirements for a single blade design were satisfied. In the proposed program, a PC based optimization method will bring together the experience and software needed to do the tasks in previous designs and allows these tasks to run iteratively to define an optimum QCS blade design. The potential of the method will be demonstrated in Phase I in a preliminary design of a 3-blade QCS propeller that meets stringent European noise certification requirements. In Phase II, the method will be completed and an optimum QCS propeller will be designed, tested, and publically demonstrated. The proposed project meets the objectives of Subtopic 03.01 for improvement in the environ-mental compatibility of subsonic aircraft through reduction of noise and improvement of passenger comfort.


The direct commercial potential for the proposed project is the manufacture and sale of: A GA airplane incorporating the proposed low-noise, 3-Blade composite propeller. Production and sale of low-noise 3-Blade composite propellers to existing aircraft owners. Production and sale of low-noise 3-Blade composite propellers to other light aircraft manufacturers. Global Aircraft Corporation is currently certifying its GT-3 Trainer airplane under FAA Part 23 Regulations. The Company currently has available funding to construct the initial production facility by November 1998. Global has adequate financial reserves in the current credit facility to finance production of the low-noise 3-Blade composite propellers to be developed and FAA certified in Phase II.


Michael R. Smith
Global Aircraft Coporation
P.O. Box 850
Starkville , MS 39760


Global Aicraft Corporation
P.O. Box 850
Starkville , MS 39760