C-108

There were several B-17 modifications such as the XB-38 (a B-17 fitted with Allison V16 liquid cooled engines), the YB-40 (a B-17 airframe equipped with armor plating and thirty[!] 50 caliber machine guns), and the C-108 (a transport version of the airplane.) A couple C-108s were equipped with luxury interiors as the personal planes for General Douglas MacArthur.

The first C-108 built (designated XC-108) was a B-17E (41-2593) converted to a V.I.P. transport for General Douglas MacArthur in 1943. With the exception of the nose and tail turrets, all armament was removed, as was all armor. The interior of the plane was made into a flying office for MacArthur, with extra windows, cooking facilities, and living space. Other changes included moving the radioman and navigator behind the pilot and copilot in the area where the top turret was previously located, opening up the bulkhead door in the rear of the bomb-bay leading to the former radio room. Hardware was added for litters, cargo or troops. To facilitate entry and exit, a drop-down door with steps was installed in the rear fuselage. A similar conversion as in XC-108 was made on a B-17F-40-VE (42-6036).

Later, similarly, for General MacArthur, the B-17F-40-VE (42-6036) was converted, designated YC-108. The next aircraft, the XC-108A, based on the B-17E (41-2595), was subjected to a more serious alteration. With it, they removed all weapons and armor, changed the crew accommodation, increasing the maximum space for the passenger cabin. The aircraft was used to deliver cargo and personnel for the B-29 base located in Chengdu (China) and operated over the Himalayas.

In connection with the problems of engines, in October 1944 it was returned to the United States, and was soon disassembled. In 1985, the surviving parts of the XC-108A were assembled by an enthusiast of aviation antiquity and taken to Galt Airport, Illinois, where the aircraft is supposed to be rebuilt.

The last transport variant of the XC-108B was redesigned from B-17F (42-30190). As with the XC-108A, all the weapons and armor were removed from it and large fuel tanks were installed. It was not used for a long time in the role of a tanker. There were also two transport modifications B-17G - CB-17G, capable of transporting up to 64 soldiers (25 such vehicles were built) and VB-17G - VIP transport for higher officers (8 aircraft).

When considering the suitability of the B-17 airplane for troop carrier operations, it was assumed that combat airplanes would be used and diverted for this type of work only for the length of time necessary to perform the mission. For this reason a stripped B-17 airplane was not tested. However, a B-17F airplane stripped of 4,000 lbs. of armor, armament and turrets was used for towing gliders by the Glider Branch, Aircraft Laboratory, YJright Field, Dayton, Ohio, and had proved satisfactory as a tow plane. The B-17F was tested, towing respectively one CG-13A glider grossing 16,500 lbs., one Horsa glider grossing 15,000 lbs., and two CG-4A gliders grossing 7,500 lbs. each. When towing the various combinations, the airplane had to fly at a very high angle of attack both while climbing and in level flight. Restricted forward visibility from the pilot's compartment is the result of this flying attitude. The restricted forward visibility and high angle of attack . attitude of the B-17 airplane when towing either two CG-4A gliders or one CG-13A glider would make flying in a troop carrier formation impracticable.

The only possible exits for parachute troops are the waist gun windows, the bomb bays, and the small door on the right rear of the waist guns. The waist gun windows, although suitable for emergency exits, would not do for parachute troops. The use of bomb bays is not considered feasible except for a very small number of men. Exits would have to be made from the walks and movement thereon is very restricted. The small door at the right rear of the waist gun compartment is not feasible for mass parachute exits because of its size and location. Although suitablo for single emergency exits, it is so small and in such position as to make its uso by parachute troops impracticable.

A total of thirty (30) fully equipped parachutists could be seated and transported in the B-17 without regard to weight and balanco. Of the thirty parachutists twenty (20} wauld havo to be soated in the bomb bay fitted with a temporary flooring. It would either be necessary to remove the flooring in order to make exits from the bomb bays, or move men to the rear and out the small door. Neither solution is satisfactory.