Mitsubishi Ki-21, part three

 

To compensate for the heavy losses against both the Hawker Hurricane and the Curtiss P-40 which the Ki-21 had to fight after Pearl Harbor, the Imperial Japanese Army Air Force (IJAAF) introduced the Ki-21-IIb, which replaced the long greenhouse style dorsal canopy by a turret equipped with a single 12,7 mm (0,5 in) Type 1 machine gun. Cockpit canopies were redesigned as well and fuel capacity was also increased. Although the Ki-21 was used in every front of the Pacific War, it was obvious that by, as early as 1942, the design was starting to be obsolete and was increasingly being shifted away from front-line service. 

In spite of its obsolescence, it remained in service until the end of the war in various roles, like transport, bomber crew and paratroop trainer, liaison and communications, special commando and secret missions and kamikaze operations. 

Near the end of the war, during the Battle of Okinawa, the remaining Ki-21s were used by Giretsu Special Forces (Giretsu was an special forces unit comprised of paratroopers) were used in strikes in Okinawa and American targets on Ryukyu islands. One noted operation was an strike on the American-held Yontan and Kadena airfields on the night of 24th May 1945. Twelve modified Ki-21-IIb with their turrets removed, of the Daisan Dokuritsu Hokutai were sent to strike, each airplane loaded with 14 commandos. Five Ki-21s managed to crash land on Yontan, only one landed successfully. The remaining raiders, armed with sub-machine guns and explosives wrought havoc on the supplies and nearby aircraft, destroying 264.979 L (70.000 US Gal) of fuel and nine aircraft, and damaging 26 more on what was the last operational usage of this Japanese bomber.

The Allied codename for the type, initially was "Jane", but it was quickly changed to "Sally" as "Jane" was the name of Douglas McArthur's wife. When the Ki-21-IIb entered service, the absence of the long greenhouse canopy confused Allied observers, who thought it was a completely new type and named it "Gwen", however, it was quickly switched back to "Sally" when they realized their mistake. 

A total of 2.064 units of every variant were manufactured,  between March 1938 and 1944 when the last Ki-21-IIb was completed.

Sources:

1. https://en.wikipedia.org/wiki/Mitsubishi_Ki-21

2. https://www.valka.cz/Micubisi-Ki-21-Sally-t31499 (translated)

3. http://www.asisbiz.com/il2/Ki-21-Sally/Mitsubishi-Ki-21-Sally.html