Douglas XCG - 17 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 successful in testing , 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 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 . 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 . Trials conducted using a conventional , powered C - 47 , first conducting ordinary deadstick landing s , then being towed by another C - 47 , indicated that the scheme was feasible . Therefore a C - 47 - DL was taken in hand for conversion into a glider , which was given the designation XCG - 17 . The aircraft , formerly a Northwest Airlines DC - 3 that had been impressed into military service at the start of World War II , 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 . Other equipment , no longer necessary with the conversion to an unpowered configuration , was also removed to save weight ; items removed included the aircraft ' s wiring and bulkheads , along with the navigator ' s and radio operator ' s positions . Operational history . 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 . The flight testing of the XCG - 17 proved that the aircraft was satisfactory ; compared to 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 . 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 in tandem and the leading aircraft detaching following takeoff . This configuration was dangerous for the " middle " C - 47 , however , and it was determined that a single C - 54 was the optimal tug aircraft . The XCG - 17 ' s cargo hold had a capacity of ; alternatively , up to 40 fully equipped troops could be transported , these figures being significantly larger than conventional gliders ' capacity . The XCG - 17 was also capable of carrying three jeeps in a single load , or alternatively two howitzer s . Regardless of the aircraft ' s load , no ballast was required to maintain the aircraft ' s center of gravity , a trait unique among American assault gliders . Despite the satisfactory results in testing , however , the aircraft failed the Army ' s requirement that it be capable of landing on unimproved fields ; in addition , by the time the evaluation of the XCG - 17 was completed the need for such a large assault glider had passed . 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 required . 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 . 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 . Some sources , however , indicate that the XCG - 17 was re - converted to C - 47 configuration in 1946 . Following its restoration to powered status , the aircraft was transferred to Mexico , where it remained in civilian service until 1980 . Field conversion . 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 a glider configuration by the Fifth Air Service Area Command , located at Nichols Field on Luzon in the Philippines , during January 1946 . 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 . Referred to as " XCG - 47 " as well as " XCG - 17 " , and named " Nez Perce " , the aircraft undertook its initial flight following conversion on June 17 , 1946 , towed by a C - 54 . The flight tests of the field - converted aircraft proved favourable , and an ambitious flight , towing the aircraft from Luzon to Tokyo in Japan , was planned . This flight was intended to prove the suitability of large gliders to act as an " aerial freight train " for regular transport . The flight , conducted in late June 1946 , took 11 hours of flight time and included an overnight stay on Okinawa ; covering , it concluded at Tachikawa Airfield near Tokyo . 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 .