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XCG-17
The XCG-17 during towed flight
Role Assault glider
National origin United States
Manufacturer Douglas Aircraft
First flight June 14, 1944
Primary user United States Army Air Forces
Number built 1
Developed from Douglas C-47 Skytrain
Type Prototype
Construction number 4588
Registration N69030
XA-JID
XC-0PS
Serial 41-18496

The Douglas XCG-17 was an American assault glider, developed by the conversion of a C-47 Skytrain twin-engine transport during World War II. Although the XCG-17 was successfully tested, the requirement for such a large glider had passed, and no further examples of the type were built; one additional C-47, however, was converted in the field to glider configuration briefly during 1946 for evaluation, but was quickly reconverted to powered configuration.

Design and development

With the introduction of the Douglas C-54 Skymaster four-engined transport aircraft, the United States Army Air Forces, observing that conventional gliders then in service [N 1] would be an inefficient use of the C-54's power and capacity, determined that a requirement existed for a new, much larger assault glider. [2] [3] It was determined that the best solution to the requirement was the conversion of the Douglas C-47 Skytrain, already in large-scale production, to meet the requirement. The C-47 could be converted to a glider configuration with minimal alteration to the airframe, and would provide the required capacity. [3]

Trials conducted using a conventional, powered C-47, first conducting ordinary deadstick landings, then being towed by another C-47, indicated that the scheme was feasible. [2] Therefore, a C-47-DL was taken in hand for conversion into a glider, which was given the designation XCG-17. [4] [5] [N 2] The aircraft, formerly a Northwest Airlines DC-3 that had been impressed into military service at the start of World War II, [7] [N 3] was modified by the removal of the aircraft's engines; the nacelles, containing the landing gear, remained in place, covered with aerodynamically profiled hemispherical domes for streamlining, containing fixed weight to compensate for the removal of the engines. [3] [7] [9] Other equipment, no longer necessary with the conversion to an unpowered configuration, was also removed to save weight; [3] items removed included the aircraft's wiring and bulkheads, along with the navigator's and radio operator's positions. [1] [7]

Operational history

The C-54 was the preferred tow aircraft for the XCG-17

The conversion, carried out at Clinton County Army Air Field, was completed on June 12, 1944, with the aircraft undergoing its initial flight test shortly thereafter. [7] The flight testing of the XCG-17 proved that the aircraft was satisfactory; compared with conventional gliders in service, the aircraft possessed lower stalling and higher towing speeds than conventional gliders, as well as gliding at a significantly shallower angle. [4] [10] Tow tests were conducted using a variety of aircraft; the most commonly used configuration was a tandem tow by two C-47s, with the towing aircraft coupled one in front of the other and the leading aircraft detaching following takeoff. [3] This configuration was dangerous for the "middle" C-47, however, [7] and it was determined that a single C-54 was the optimal tug aircraft. [2] [7]

The XCG-17's cargo hold had a capacity of 15,000 pounds (6,800 kg); [1] [7] [9] alternatively, up to 40 fully equipped troops could be transported, these figures being significantly larger than conventional gliders' capacity. [3] The XCG-17 was also capable of carrying three jeeps in a single load, or alternatively two 105-millimetre (4.1 in) howitzers. [7] Regardless of the aircraft's load, no ballast was required to maintain the aircraft's center of gravity, [3] a trait unique among American assault gliders. [7]

Despite the satisfactory results in testing, however, the aircraft failed the Army's requirement that it be capable of landing on unimproved fields; [7] in addition, by the time the XCG-17's evaluation was completed the need for such a large assault glider had passed. [1] [9] The primary role for the glider had been intended to increase the amount of supplies that could be carried to China over " The Hump"; the war situation had, however, become more favorable and the added capacity an oversized glider would provide was no longer necessary. [11] No further examples of the type were produced; the prototype, its trials complete, was placed in storage, being ferried to Davis-Monthan Air Force Base for disposal in August 1946. [7]

In August 1949, the aircraft was sold to Advance Industries, its engines being reinstalled to return the aircraft to powered status in DC-3C configuration. [7] Some sources, however, indicate that the XCG-17 was reconverted to C-47 configuration in 1946. [9] Following its restoration to powered status, the aircraft was transferred to Mexico, [7] where it remained in civilian service until 1980. [12]

Field conversion

"Nez Perce"
"Nez Perce" after conversion to glider configuration
Other name(s) XCG-47; XCG-17
Type Field-converted glider
Manufactured 1946
Serial 43-16229
First flight June 17, 1946 (as glider)
Fate Reconverted to C-47

Although the XCG-17 failed to lead to any production of a C-47 derived glider type, a single C-47 was converted in the field to glider configuration by the Fifth Air Service Area Command, located at Nichols Field on Luzon in the Philippines, during January 1946. [7] Carried out in much the same manner as the XCG-17, the conversion included octagonally shaped fairings over the engine mountings, with an auxiliary power unit from a B-24 Liberator bomber being installed. [7]

Referred to as "XCG-47" as well as "XCG-17", and named "Nez Perce", [7] the aircraft undertook its initial flight following conversion on June 17, 1946, towed by a C-54. [7] The flight tests of the field-converted aircraft proved favorable, and an ambitious flight, towing the aircraft from Luzon to Tokyo in Japan, was planned. [7] This flight was intended to prove the suitability of large gliders to act as an "aerial freight train" for regular transport. [7]

The flight, conducted in late June 1946, took 11 hours of flight time and included an overnight stay on Okinawa; covering 1,800 miles (2,900 km), it concluded at Tachikawa Airfield near Tokyo. [7] Despite the success of the flight, the "aerial freight train" concept did not catch on; the aircraft had its engines re-fitted in August 1946 and was returned to service as a normal C-47. [7]

Operators

Military (as C-47, then XCG-17)

  United States

Civilian (as DC-3C)

  Mexico

Specifications (41-18496)

Data from [3] [11] [13]

General characteristics

  • Crew: Two (Pilot and copilot)
  • Capacity: 15,000 pounds (6,800 kg) cargo or 40 troops
  • Length: 63 ft 9 in (19.43 m)
  • Wingspan: 95 ft 6 in (29.11 m)
  • Height: 17 ft (5.2 m)
  • Wing area: 987 sq ft (91.7 m2)
  • Empty weight: 11,001 lb (4,990 kg)
  • Gross weight: 26,000 lb (11,793 kg)

Performance

  • Maximum speed: 290 mph (470 km/h, 250 kn) max towing speed
  • Cruise speed: 190 mph (305 km/h, 165 kn) gliding speed
  • Stall speed: 35 mph (56 km/h, 30 kn)
  • Maximum glide ratio: 14:1
  • Wing loading: 26.3 lb/sq ft (128 kg/m2)

See also

Related development

Aircraft of comparable role, configuration, and era

Related lists

References

Notes

  1. ^ The Waco CG-4 was the glider most commonly used by the USAAF during World War II. [1]
  2. ^ In the U.S. Army Air Forces' designation scheme, the "-DL" suffix indicated an aircraft built at Douglas' Long Beach, California factory. [6]
  3. ^ A variety of DC-3 series aircraft were impressed into military service at the start of the war. While DC-3 series aircraft constructed for the military were given the designation C-47, impressed aircraft received a variety of designations, including C-47, C-48, C-49, C-50, and C-53, among others. Confusing things further is that the C-53 designation was also assigned to purpose-built military DC-3s, named Skytrooper, that were intended exclusively for personnel transport. [8]

Citations

  1. ^ a b c d Nigl and Nigl 2007, pp.16-17.
  2. ^ a b c Swanborough and Bowers 1989, p.274.
  3. ^ a b c d e f g h Taylor 1991, p.151.
  4. ^ a b Francillon 1988, p.233.
  5. ^ Davis 1995, p.40.
  6. ^ Bowers 1986, p.85.
  7. ^ a b c d e f g h i j k l m n o p q r s t u Day 2001
  8. ^ Davis 1995, p.31.
  9. ^ a b c d Grim 2009, p.17.
  10. ^ Serling 1997, p.62.
  11. ^ a b "XCG-17" (in Russian). Airwar.ru. Retrieved 2011-01-20.
  12. ^ a b Baugher 2010
  13. ^ Francillon 1988

Bibliography

External links

Media related to Douglas XCG-17 at Wikimedia Commons

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