While recovering from this virus from hell I was doing some reading and came across a reference in a 1952 Field Manual for the Airborne which listed the types of planes used for landing in small unimproved fields which the gliders land in - the C-153. This continues on an avenue of research I have been doing on the continued evolution of gliders during and after the war so down the rabbit hole I went. (If you are interested in the CG-13A or the CG-15A you can see my article Whisper Ships, National Soaring Museum Journal, Winter 2024)
A number of designs were produced after the CG-15A as glider tactics were updated and larger, more powerful tow planes were being used and towed the gliders at higher speeds. The C-47 was modified into a glider, the XCG-17 (Experimental Cargo Glider - Number 17) to fly the hump in the CBI with a cargo load of 15,000 lbs. The quickly changing situation in 1944 negated the need for it. There was also a need for a metal skinned glider which was reusable, this would substantially reduce the cost of production when weighed against the usage since the one-way flight of the CG-4A made it a very expensive glider.
The XCG-20 (Experimental Cargo Glider - Number 20) made another giant leap. It was a metal fuselage with aluminum siding and engines could be mounted. Like the CG-13A it had tricycle landing gear although in this further development it was retractable. The military also wanted a more versatile glider which could have engines mounted so that too was put into the design. The wingspan was 110 feet and although this sounds like a large change, I discuss in my book how the military originally wanted power pilots for gliders because they foresaw gliders being the size of bombers. In the end it was not used as a glider but instead became the C-123 referred to in the 1952 Field Manual for the Airborne which I was reading. It is no surprise the manual states it could land in unimproved fields that gliders landed in. The final bonus? According to James Mrazek it became America's first jet transport.
So if anyone tells you the WWII glider technology only lasted a short time period . . . . .
Finally found my copy of American Gliders of World War Two by Bill Norton and he lists the powered version as the C-123?