Two H-21B used for engine test, 1958-1960. Piston engine replaced by either one or two gas turbine engine of two different marks. Both later retrofitted with piston engines and delivered as UH-21B, 1962.
List of Operators of Piasecki H-21D
|From||Organisation with model H-21D|
|Construction Numbers on database of H-21D|
|B-167||1958|| 57-2610 : h-21b Vertol V-42A, cn B-167, ff:?; ordered by USAF as H-21B + |
|B-168||1958|| 57-2611 : h-21b Vertol V-42A, cn B-168, ff:?; ordered by USAF as H-21B + |