Northrop Grumman has released a photo of the Series Hybrid Electric Propulsion AiRcraft Demonstration (SHEPARD) XRQ-73 stealth drone X-plane that it has built for DARPA and is expected to fly by the end of the year.
Part of DARPA's X-Prime program, the XRQ-73A is a demonstrator prototype built by Northrop Grumman and Scaled Composites. The flying wing design is based on the Air Force Research Laboratory (AFRL) Great Horned Owl (GHO), an Intelligence Advanced Research Projects Activity (IARPA) program, which used a blended wing design and external ducted push propellers.
In contrast, the XRQ-73A is larger and stealthier. With a wingspan of well over 30 ft (9 m), it weighs in at 1,250 lb (567 kg) and can reach speeds of 250 kn (287 mph, 463 km/h) at an altitude of 18,000 ft (5,500 m) with a payload of 400 lb (180 kg).
Neither DARPA or Northrop Grumman have released many details about the craft, but the latest photo gives armchair aeronautical engineers some clues to play with. It has a broad, tapering shape that ends in clipped wingtips,
The hybrid electric propulsion system of four ducted fans is built inside the wing/fuselage, with two electric generators powered by diesel, gasoline, or aviation fuel. There are also two large air intakes forward and outlets aft. These are shaped to reduce visual and radar profiles to a minimum. Since it isn't a jet, the heat signature is likely equally small.
Another point are the two small holes in the fairing between the air inlets. These are likely mounting places for sensors or other payloads. In addition, there's a pitot boom, though that's likely to be for gathering data during flight tests.
Like the GHO, the XRQ-73A is intended to be an ultra-quiet, high-efficiency reconnaissance drone requiring both stealth and endurance for long flight times.
Source: Northrop Grumman
