The goal of the proposed NASA SBIR project is to design, develop, FAA certify, and manufacture an integrated aero/acoustic improvement to propeller driven General Aviation airplanes to reduce cabin and community noise and increase propulsive efficiency and fuel economy. The elements of the integrated propulsion system improvement include (1) modifying the engine cowl to be more axisymmetric to reduce propeller/cowl interference noise, (2) extending and aerodynamically refining the forward portion of the cowl to reduce the amount of acoustic disturbance caused by the cowl, (3) employing a modern propeller design to reduce susceptibility to inflow distortion, and (4) modifying the wind screen configuration to reduce separated flow that causes cabin broadband noise. Recent public surveys by the NASA AGATE Program have revealed that cabin noise and airframe vibration are two of the largest detriments to public acceptance of GA aircraft for transportation. The proposed project is consistent with the objectives of RFP Topic 02 to effect dramatic reductions in light aircraft reduce community noise by 10 EPNdB within ten years and to reduce cabin noise to increase passenger comfort. It is also consistent with the NASA Acoustics Program, the goals of the NASA AGATE Program, and the proposed NASA Small Airplane Transportation System (SATS).
Potential Commercial Applications:The direct commercial potential for the proposed project is the manufacture and sale of: A general aviation airplane incorporating the proposed aero/acoustic technology. Production and sale of improved engine cowls to existing aircraft owners. Production and sale of improved engine cowls to other light aircraft manufacturers. Global Aircraft Corporation is currently certifying its GT-3 Trainer airplane under FAA Part 23 Regulations. The Company is in the process of starting production of a revolutionary new composite propeller that has been developed under the NASA SBIR Program. The Company currently has available funding to construct the initial production facility by November 1999. Global has adequate financial reserves in the current credit facility to finance production of the Aero/Acoustic Cowl to be developed and FAA certified in Phase II. The proposed aero/acoustic cowl will be complimentary to the Quasi-Constant Speed Composite Propeller developed by the Company and currently starting production. The combined noise reduction of the propeller (5-8 dBA) and the aero/acoustic cowl will produce significant noise reduction in both community noise and cabin noise and should be well received by aircraft owners and the general public.
