It wasn't until summer of 1965 that the USAF's Air Rescue Service finally had a helicopter capable of sustained combat search and rescue operations in the expanding war in Vietnam. Previous helicopter rescue efforts relied on either the short-ranged Kaman HH-43 Husky or Air America's Sikorsky UH-34s, both of which weren't well-suited to the role demanded by the ARS. The transport version of the Sikorsky SH-3 Sea King, the CH-3C, had an aft loading ramp and boasted significantly better performance and load-carrying capability than anything else in-theater for CSAR. Due to their green and tan camouflage, the CH-3Cs got the nickname "Jolly Green Giant" which became their radio callsign, JOLLY GREEN.
But the Air Rescue Service wanted more out of the CH-3C despite the leap it presented. The USAF and Sikorsky developed a modified CH-3C version custom-tailored to combat search and rescue designated the HH-3E that had more powerful engines, titanium armor plating, gun mounts for M60s or GAU-2B Miniguns, and most importantly, more fuel. Not only did the HH-3E carry 200 more gallons of fuel over the CH-3C, but the landing gear sponsons were also plumbed to carry 200-gallon drop tanks. But the great technological and operational leap would be the ARS's desire to be able to refuel the HH-3E in midair.
No helicopter had been refueled in midair- the USAF had standardized on the Boeing flying boom which would have been impossible to use on a helicopter in addition to the speed mismatch between the KC-135 Stratotanker and the HH-3E. It was decided to use the Navy's probe and drogue method, but the slipstream of the tanker and rotor downwash made airborne refueling still tricky.
Sikorsky's engineers developed a telescoping refueling probe that when fully extended, put the tip of the probe just outside the rotor downwash. The USAF borrowed a US Marine Corps KC-130 Hercules for flight trials at Wright-Patterson AFB in Ohio. Pilots found that the boat-like hull of the HH-3E could in effect "float" on the Hercules' slipstream. Tests were completed in 1966 and Lockheed was contracted to convert 11 C-13oHs into HC-130 aerial tankers that also functioned as airborne controllers for any rescue operation. The first HC-130Ps arrived in SE Asia in November 1966 to join up with the HH-3Es already in theater since late 1965 (with the CH-3Cs being phased out by January 1966).
The Sikorsky HH-3E "Jolly Green Giant" would be the world's first helicopter equipped for aerial refueling, giving USAF combat search and rescue a quantum leap in capability at a time when the war effort in Vietnam was expanding daily.
Source: Wings of Fame, Volume 14. AIRtime Publishing, 1999, "'That others may live': USAF Search and Rescue, Part Two, 1958-1975 - The war in Southeast Asia" by Larry Davis, p22-25.
