If KC-135Qs were unavailable, ordinary Stratotankers could be used to refuel the SR-71 Blackbird Mach 3+ spy plane.
If it weren’t for air refueling, the SR-71’s range would be relatively limited—roughly 2,000 NM. The aircraft’s range was increased by several air refuelings to the crew’s maximum endurance. Many missions have gone above 12,000 NM. The SR-71 and KC-135Q tankers’ forward basing allowed for increased overall efficiency, shorter range, shorter length missions, and faster responses.
There were various ways in which KC-135Q crews and their aircraft were different from other Air Force units. Col. Richard H. Graham, a former Blackbird pilot, explains in his book ‘SR-71 The Complete Illustrated History of THE BLACKBIRD The World’s Highest, Fastest Plane‘ that their boom operators were the only ones qualified to refuel the SR-71, and their aircrews were the only ones certified in Blackbird’s specific radio-silent rendezvous procedures. The Q-model tankers could move JP-4 and JP-7 fuel between different tanks because of the special plumbing between the tanks. They could use JP-4 or JP-7 fuel in their engines. In fact, KC-135Q tankers could carry up to 110,000lb of JP-4 and 74,490lb of JP-7 for their own engines at the same time.
If the SR-71 landed in an area without JP-7 fuel, the Q-model tankers would fly in with the fuel and refill the aircraft using ground-based transfer hoses.
However, as recently explained, in the case that KC-135Qs were unavailable, the SR-71 could also be refueled using conventional Stratotankers.
Earl Belz, former KC-135A crew chief, said:
‘In 1978, I was a Crew Chief on a KC-135A model tanker. We were TDY from Carswell AFB in Ft. Worth, Texas to RAF Mildenhall, UK. While we were there at Mildenhall there was some type of political election or changing of political parties (they were having an election of the Prime Minister or something like that). Because of that, there couldn’t be any foreign reconnaissance (spy) aircraft in England.
‘There were two SR-71s and one U-2 also TDY at Mildenhall. They couldn’t get a Q model there in time, so we were directed to defuel and purge some of our center body fuel tanks of the JP-4, and we were given instructions to load JP-7 in those tanks to support refueling one of the SR-71s (thus separating the JP-7 from our KC-135’s own fuel supply). It’s known as “flying dirty.”
‘We did as directed and took off with one of the SR-71s the following day. We accomplished two refuels. One immediately after getting airborne and a second one about an hour later. I believe the SR-71 was going to Zaragoza, Spain, to remain overnight, at which point it was going to get Q model support to return to Beale. We returned to Mildenhall to finish the reminder of our TDY.’
He continues;
‘I’ve got a couple of photos [shown below] I took while hooked up to the SR-71. Pretty awesome.
‘I took these pictures with my Kodak 110 camera. The one taken from the boom pod has a couple of spots were the photo got stuck to the plexiglass picture frame, but this was the first refuel immediately after we took off. He was moving into position for hooking up. We only refueled it twice. The SR-71 was going to Zaragoza, and a Q model was supposedly going to be there the next day.
‘The second SR-71 photo was another one that took off the day before.
‘The third photo was a U-2 that was at Mildenhall at the same time the two SR-71s were there.’
Belz concludes;
‘Sorry about the quality of the pictures but I was just an E-4 Crew Chief.’
Photo by U.S. Air Force, Tony Landis Lockheed and Earl Belz