R - Rotary Wing Aircraft

Model	Designation	Manufacturer	Engine(s)	Crew	Other
XR-1		Platt-LePage	2 Pratt & Whitney R-985 Wasp Junior
XR-1A		Platt-LePage	2 Pratt & Whitney R-985 Wasp Junior
XR-2		Kellett	1 Jacobs R-915-3	2	YG-1C
XR-3		Kellett	1 Jacobs R-775-1	2	YG-1B
XR-4	Hoverfly	Sikorsky	1 Warner R-500-3	2
YR-4A	Hoverfly	Sikorsky	1 Warner R-550-3 Super Scarab	2
YR-4B	Hoverfly	Sikorsky	1 Warner R-550-1/3 Super Scarab	2	YH-4B
R-4B	Hoverfly	Sikorsky	1 Warner R-550-1/3 Super Scarab	2	H-4B, HNS-1
XR-4C	Hoverfly	Sikorsky	1 Warner R-550-1 Super Scarab
XR-5	Dragonfly	Sikorsky	1 Pratt & Whitney R-985-AN-5 Wasp Junior	2
XR-5A	Dragonfly	Sikorsky	1 Pratt & Whitney R-985-AN-5 Wasp Junior	2
YR-5A	Dragonfly	Sikorsky	1 Pratt & Whitney R-985-AN-5 Wasp Junior	2	YH-5A
R-5A	Dragonfly	Sikorsky	1 Pratt & Whitney R-985-AN-5 Wasp Junior	2	H-5A, HO2S-1
R-5B	Dragonfly	Sikorsky			cancelled
XR-5C	Dragonfly	Sikorsky			cancelled
R-5D	Dragonfly	Sikorsky	1 Pratt & Whitney R-985-AN-5 Wasp Junior	3	H-5D
YR-5E	Dragonfly	Sikorsky	1 Pratt & Whitney R-985 Wasp Junior	2	YH-5E
R-5F	Dragonfly	Sikorsky	1 Pratt & Whitney R-985-AN-5 Wasp Junior	2	H-5F
XR-6	Hoverfly II	Sikorsky	1 Franklin O-405-9	1
YR-6A	Hoverfly II	Sikorsky	1 Franklin O-405-9	1
R-6A	Hoverfly II	Sikorsky	1 Franklin O-405-9	1	HOS-1
R-7		Sikorsky	1 Franklin O-405		cancelled
XR-8		Kellett	1 Franklin O-405
XR-8A		Kellett	1 Franklin O-405		XH-8
XR-9B		Firestone	1 Lycoming O-290	2
XR-10		Kellett	2 Pratt & Whitney R-985 Wasp Junior		YH-10A
XR-11		Rotorcraft	1 Continental A100		XH-11
XR-12		Bell	1 Franklin 6V4	1	XH-12
R-12A		Bell	1 Franklin 6V4	1	cancelled
XR-12B		Bell	1 Pratt & Whitney R-1340 Wasp		XH-12B
YR-12B		Bell	1 Pratt & Whitney R-1340 Wasp		YH-12B
YR-13	Sioux	Bell	1 Franklin O-335	2	HTL-1
YR-13A	Sioux	Bell	1 Franklin O-335-1		YH-13A
R-14		Firestone			H-14, cancelled
XR-15		Bell	1 Continental O-470 and Reaction Motors LR32		XH-15
YR-16	Transporter	Piasecki	2 Pratt & Whitney R-2180-11 Twin Hornet		YH-16