US 12,275,533 B2
Inlet system for auxiliary power unit
Bruce Bouldin, Phoenix, AZ (US); and Adam Kowal, Phoenix, AZ (US)
Assigned to HONEYWELL INTERNATIONAL INC., Charlotte, NC (US)
Filed by HONEYWELL INTERNATIONAL INC., Charlotte, NC (US)
Filed on Jun. 2, 2023, as Appl. No. 18/327,965.
Prior Publication US 2024/0400219 A1, Dec. 5, 2024
Int. Cl. F02C 7/042 (2006.01); B64D 33/02 (2006.01); B64D 41/00 (2006.01)
CPC B64D 33/02 (2013.01) [B64D 41/00 (2013.01); F02C 7/042 (2013.01); B64D 2033/0213 (2013.01); F05D 2220/50 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An inlet system for an auxiliary power unit, comprising:
an inlet duct having a forward wall and a most aft wall;
a frame coupled about the inlet duct, the frame defining an opening configured to be in fluid communication with an ambient environment and the inlet duct;
a door having a first end opposite a second end, the door coupled to the frame at the second end, the door configured to move relative to the frame between at least a first, closed position in which the door cooperates with the frame to inhibit airflow into the inlet duct and a second, opened position, in the second, opened position the door is configured to enable the airflow into or out of the inlet duct, the door defining a ramp at the second end;
a hook extending from the most aft wall and coupled to the frame proximate the inlet duct and proximate the second end of the door, the hook located at least partially forward of the second end and spaced a distance apart from the ramp to define a first gap;
a second gap defined by the frame and the second end, the second gap aft of the second end, the first and second gaps to enable the airflow into or out of the inlet duct in the second, opened position, the enabled airflow including at least an airflow into the auxiliary power unit from the ambient environment and through the second gap at the second end.