The Short Brothers (sometimes shortened to "Shorts") concern was formed in 1908 with operations settled out of London (having since moved to Belfast, Ireland). The company made a name for itself in World War 1 as a manufacturer of floatplane aircraft and airships. Throughout the 1920s and 1930s, they became renowned for their series of flying boats that saw extensive service throughout World War 2 and in the subsequent Cold War. The Short concern continues operations today despite its sale to Bombardier in 1989 as a manufacturer of aircraft, aviation parts and systems.
With this long-running, storied history in place, Short developed the Short 330 in the early 1970s, the type eventually adopted into civilian service beginning in 1976. The 330 was a further evolution of the SC.7 Skyvan though given a lengthened fuselage and larger dimensions overall. Originally known under the SD3-30 designation, the 330 was marketed as a low maintenance product and retained the former's high-mounted wings, deep slab-sided fuselage and noticeably raised empennage. The aircraft were developed as rather compact, transport-minded, twin-engined airframes with good Short Take-Off and Landing (STOL) characteristics, allowing it to operate from shorter airfields than other aircraft of this class. The first 330 went airborne on August 22nd, 1974.
The United States Air Force took note of the type and placed an order for eighteen units in March of 1983 as part of Military Airlift Command (MAC), intended to serve primarily across American bases in Europe. The models were designated as C-23A "Sherpa" and did not feature fuselage windows while also being outfitted with a conveyor system and hydraulically-powered rear loading doors as well as a portside loading door. This variant of the Sherpa is powered by 2 x Pratt & Whitney Canada PT6A-45-R series turboprop engines, each delivering 1,200 horsepower for a maximum listed speed of 280 miles per hour and a listed cruise speed of 255 miles per hour. Operational range is approximately 770 miles with a service ceiling of 27,000 feet. The first C-23A began operational service with the USAF in 1985. USAF Sherpas operated until 1990.
The Sherpas were crewed by three personnel made up its two pilots and a cabin manager. The fuselage could be arranged to seat 30 passengers in the traditional sense or 18 medical litters with associated personnel for when in the MEDEVAC role. Beyond this, the cabin was also set up to accept cargo of varying sizes. The Sherpa certainly displayed a most unique profile and retained much of the appearance of the preceding Short 330 series including its pointed downward sloping nose, strutted shoulder-mounted wings, boxy fuselage design and underslung engine nacelles. The undercarriage was wholly retractable though rather short, allowing the hold to be accessible from the rear without much height difference.
The C-23B designation was used to recognize Sherpas handed down from the USAF to the Army National Guard. The ANG also accepted 10 new-build units for a grand total of 16 examples. While essentially similar to the C-23A before it, the Army National Guard version incorporated a span of rectangular windows along the fuselage sides and power was served through 2 x Pratt & Whitney Canada PT6A-65AR turboprop engines of 1,425 horsepower each. These have seen operational service in Iraq since the 2003 coalition invasion.
Some twenty-eight preowned Short 360 models were procured by the United States Army and promptly converted to a new C-23B+ / C-23C "Super Sherpa" standard in line with the C-23A and C-23B before it. The US Army contracted West Virginia Air Center to modify the airframes from their original single vertical tailfin state to the C-23A/B-style twin-rudder configuration. The process also added the powered loading ramp of the of the preceding marks as well as modernized military-grade avionics. The conversion process spanned from 1994 to 1997.