US 11,718,403 B2
Extremely quiet short take-off and landing (STOL) aircraft
Kyle Rahrig, El Segundo, CA (US); Geoffrey Sommer, El Segundo, CA (US); and Barnaby S. Wainfan, Long Beach, CA (US)
Assigned to NORTHROP GRUMMAN SYSTEMS CORPORATION, Falls Church, VA (US)
Filed by Northrop Grumman Systems Corporation, Falls Church, VA (US)
Filed on Apr. 15, 2015, as Appl. No. 14/687,277.
Prior Publication US 2016/0318606 A1, Nov. 3, 2016
Int. Cl. B64C 39/06 (2006.01); B64C 11/00 (2006.01); B64D 29/02 (2006.01); F02K 1/34 (2006.01); B64C 15/14 (2006.01); B64D 35/08 (2006.01)
CPC B64C 39/066 (2013.01) [B64C 11/001 (2013.01); B64C 15/14 (2013.01); B64D 29/02 (2013.01); B64D 33/06 (2013.01); B64D 35/08 (2013.01); Y02T 50/40 (2013.01); Y02T 50/60 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A short take-off and landing (STOL) aircraft comprising:
two wings,
wherein each wing comprises an engine system;
a fuselage structurally connected to each wing;
channel shrouds surrounding at least one of the engine systems, at least one of the channel shrouds filled with a sound attenuating material, at least one of the channel shrouds providing lift to the STOL aircraft, at least one of the channel shrouds reflecting acoustic energy upwards, at least one of the channel shrouds being elongated to provide enhanced noise shielding, the engine systems driving a propeller, the channel shrouds located outside the fuselage, wherein the channel shrouds hemi-cylindrically surround a lower half of the propeller, the propeller located at a longitudinal center of the channel shrouds, wherein a chord-wise location of the propellers minimizes an associated acoustic signature and maximizes acoustic shielding of radiated acoustic energy; and
a ducted fan thruster positioned on the fuselage in an orientation that is rotated relative to the typical orientation of a main rotor on a helicopter, wherein the STOL aircraft is configured to approach a landing zone substantially inaudibly, wherein ingress and egress of the STOL aircraft are both substantially inaudible, wherein the STOL aircraft is configured to do one or more of land in an ultra-short takeoff and landing zone and take off from the ultra-short takeoff and landing zone even if required to clear an obstacle of up to approximately fifty feet in height, wherein a representative radius of operation for the STOL aircraft comprises approximately 500 nautical miles, wherein a representative velocity of the STOL aircraft on takeoff is approximately fifty knots, wherein a representative payload for the STOL aircraft is between approximately 2,000 pounds and approximately 3,000 pounds.