The Sikorsky R-4 would gain the distinction of being the first helicopter to be mass produced and the first one to serve the USAAC, USN and U.S. Coast Guard. Seen here is the XR-4 during naval testing. (USCG photo)
The Sikorsky R-4 would gain the distinction of being the first helicopter to be mass produced and the first one to serve the USAAC, USN and U.S. Coast Guard. Seen here is the XR-4 during naval testing. (USCG photo)