Northrop Grumman RQ-72 Great Horned Owl
GHO (Great Horned Owl) was an IARPA (Intelligance Advanced Research Projects Activity) program to develop an extremely quiet surveillance drone.
The program began in 2011, and was supported by the USAF's Air Force Research Laboratory (AFRL). A core part of the concept was a hybrid electric propulsion, to combine the advantages of quiet electric motors with the endurance of modern combustion engines. In the GHO vehicle, the combustion engine would produce the power to drive an electric motor for the actual propulsion system.
Scaled Composites, a subsidiary of Northrop Grumman, reportedly received a contract to design and build the GHO airframe. Documents released by AFRL show a small flying wing design with four shrouded propellers on top of the wing. Separate contracts went to small companies to provide the power source and the propulsive system.
|Image: USAF, via The War Zone
Very little information about the timeline of the GHO program is available. The AFRL requested the assignment of an MDS designation only in early 2017, and the wording of the request indicates that the first flight of the vehicle was still in the future then. In March that year, the designation XRQ-72A was approved. No further information, like a first flight date or the termination of the program, has come forward. However, in 2018 IARPA started a program called LHO (Little Horned Owl), which is to create a very quiet miniature UAV, much smaller than LHO. By name and objective, LHO seems to be a follow-up to GHO, so that the latter may have been finished by that time.
Designation Note: When requesting an official MDS designator for the GHO vehicle, the AFRL asked for an X-plane designation (X-##A), which is quite usual for a purely experimental aircraft. However, the MDS approval authority apparently interpreted the program as the development of a potentially operational reconnaissance UAV, for which an XRQ prefix is more appropriate. But the design number 72 is out of range in the Q-series, and no explanation for the choice of that number is available.
Note: Data are availble for a notiomal GHO design only. Figures given below may therefore be inaccurate!
Data for XRQ-72A:
|3.4 m (11.2 ft)
|9.1 m (30 ft)
|1.2 m (4 ft)
|135-180 kg (300-400 lb)
|4 electric motors
 Joseph Trevithick:
Exclusive: Unmasking Northrop Grummanís XRQ-72A Great Horned Owl Spy Drone
 IARPA GHO
 IARPA LHO
Last Updated: 8 January 2024