Following the A model, the USAF ordered 168 H-21Bs [51-15854..15880, 52-8665..8679, 52-8681..8709, 53-4322..4402, 54-4000..4008, 55-5127..5131, and 57-2610..2611]. From this USAF contract, the French received 12 H-21Bs [54-4000..4008, 55-5127..5131]. The B model was equipped with the R-1820-103 Cyclone engine developing 1425 HP and had a pilot-activated, two-stage, electrically engaged supercharger. 
List of Operators of H-21B |
| Years | Model | Org | |||||
|---|---|---|---|---|---|---|---|
| 1952/74 | H-21 |  US Air Force | |||||
| 1955- | H-21 |  Royal Canadian Air Force (1945-1968) | |||||
| 1956/60 | H-21 |  Aéronautique Navale | |||||
| 1956- | H-21 |  Japan Air Self-Defense Force | |||||
| | H-21 | Spartan Air Services Ltd | |||||
| H-21 | Aviation Légère de l'Armée de Terre | ||||||
Global Distribution of H-21B |
|
Construction Numbers |
| C/N | Year | History | |
|---|---|---|---|
| B-1 | 51-15854 | ||
| B-2 | 51-15855 | ||
| B-21 | 02-4751,51-15874 | ||
| B-24 | 02-4752,51-15877 | ||
| B-26 | 02-4753,51-15879 | ||
| B-31 | 02-4754,52-8668 | ||
| B-61 w/o 1964 | 02-4755,52-8699 | ||
| B-72 | 53-4322,FG-322 | ||
| B-74 | 53-4324 | ||
| B-76 | 1955 | 53-4326,N6792 | |
| B-117 | 53-4367,N4367M | ||
| B-129 w/o 1961 | 53-4379 | ||
| B-136 w/o 1956 | 1954 | 31.F.1,53-4386 | |
| B-137 scrapped 1968 | 1954 | 31.F.2,53-4387 | |
| B-138 w/o 1956 | 1954 | 31.F.3,53-4388 | |
| B-146 | 1956 | 53-4396,9641,CF-JJO | |
| B-148 | 1956 | 02-4756,53-4398,8 000 108 | |
| B-149 w/o 1966 | 1956 | 02-4757,53-4399,8 000 109 | |
| B-150 scrapped 1968 | 1955 | 53-4400,8 000 110,F-YDCE | |
| B-154 | 1956 | 54-4001,8 000 114,F-YDCB,N64606 | |
| B-159 w/o 1963 | 02-4758,54-4006 | ||
| B-160 | 02-4759,54-4007 | ||
| B-161 | 02-4760,54-4008 | ||
| B-162 | 1956 | 31.F.3,55-5127,8 000 xxx,FR15 | |
| B-163 scrapped 1968 | 1956 | 31.F.4,55-5128,8 000 yyy | |
| B-164 w/o 1957 | 1956 | 31.F.5,55-5129 | |
| B-165 w/o 1957 | 1956 | 31.F.6,55-5130 | |
| B-166 scrapped 1968 | 1956 | 31.F.7,55-5131 | |
| B-167 | 1958 | 57-2610 | |
| B-168 | 1958 | 57-2611 | |
| B-439 | 9594,CF-JJV | ||
| B-459 | 9595,CF-JJW | ||
| C.304 | 1957 | 56-2142 |
