The Lockheed YF-12 was an American prototype interceptor aircraft developed and manufactured by American aerospace company Lockheed Corporation during the late 1950s and early 1960s as a potential replacement for the F-106 Delta Dart interceptor for the United States Air Force. The YF-12 was a twin-seat version of the then-secret single-seat Lockheed A-12 reconnaissance aircraft operated by the Central Intelligence Agency at Area 51. Unlike the A-12, it was furnished with the Hughes AN/ASG-18 fire-control radar and armed with AIM-47 Falcon (GAR-9) air-to-air missiles. Performing its maiden flight on 7 August 1963, President Lyndon B. Johnson revealed the YF-12’s existence on 24 February 1964; this move was to provide the CIA-operated A-12 fleet at Area 51 plausible deniability.

On 1 May 1965, five years to the day of the Russians shooting down Gary Powers,  I participated in the 1965 record-setting speed run while working as a field engineer at the NASA High Range’s Beatty station. The speed runs were the 8th US Secretary of Defense Robert McNamara’s strategy to lure the Russians to beat the YF-12 records with their Foxbat MiG 25. He restricted the speed to 2,000 mph and the altitude to 80,000 feet, 2% faster than the Russians.

YF-12A Article 936 set nine world absolute speed and altitude records on 1 May 1965. Following an engine malfunction in Article 934, Col. Robert “Fox” Stephens and Maj. Daniel Andre flew Article 934 on a closed-course flight at 2,070.101 mph and 80,257.65 feet. Lt. Col Walter Daniel and Maj. James Cooney set a closed course record in 936 at 1,688.891 mph. Daniel and Maj. Noel Warner set another record at a speed of 1,643.041 mph over a closed course.

AFFTC History Office

The Lockheed YF-12 conducted the speed and altitude runs, and an Air Force YF-12 the closed course with a payload of 2000 Kilos in five compartments.

The French Aerospace Agency monitored & verified the records, using visual references from the ground. To facilitate visual verification at 80,000 feet, the YF-12 had a white cross on its bottom. When Flight Test Operations signaled, the pilot activated a five-second fuel dump switch to identify the aircraft’s location by the fuel appearing as a contrail behind the white cross.

At the NASA High Range’s Beatty tracking station, we were on-site at 0420 hours to preflight the radar, communications, and data collection/transmission systems.

YF-12A Unveiling at Edwards
9/30/64
AFFTC History Office

The first flight occurred at 0530 with the Lockheed YF-12  Article 934, flown by  Systems Command Col Fox Stephens and Maj Dan Andre. At launch, Lockheed had 32 engineers at the plane checking their systems.

On the climb out over Las Vegas, Stevens and Andre experienced a fire warning light. They shut the engine down and returned to Edwards/Dryden, where they overshot the final, forcing Kelly Johnson and others to seek shelter behind a truck.

Stephens & Andre then replaced Lt Col Walt Daniel and Maj Noel Warner in YF-12 Article 936 to continue the speed run on a 15×25 Km course with one run east to west and the second west to east with a 300-foot restriction after the first run to keep from climbing and diving during the second run.

The first run was too slow, and the crew told them to increase their speed. They raised the rate to over 2,000 mph.

The observers from Washington, DC included a three-star general who called President Johnson to see if the speed was okay or did the president want a slower rate. The president approved the speed at 2,069.5 mph.

Lockheed determined Article 934’s firelight indication to be a faulty switch. Flight cut the wire to the controller, allowing Stevens and Andre to conduct the closed course altitude run carrying 2,000-kilo weight in five compartments, setting a sustained altitude record of 80,257.65 feet 2,070.101-mph closed course record.

We set the speed and altitude records on separate flights because of an altitude restriction. To get to Mach speed, the YF-12 had to exceed 80,000-feet.

What many don’t know is that the Air Force repaired 19 titanium cracks during the turnarounds.

Lockheed attempted another late altitude run but aborted the takeoff due to a brake problem.

These record-setting events were the first time for a Blackbird to make three turns at Mach speed in one day. The Air Force prepared and hoped to fly a fourth flight should Lockheed not make the altitude run. The Air Force wanted all of the records held by its YF-12. Stephens & Andre did get the Altitude Record, measured by radar at 80,202-feet.

The weight procedures required a specific type scale with a very current certification. The French verification team observed the loading and placed a sticker on each compartment to ensure that no one had removed the Mach 3+ record flights’ weights. After the third flight, they used magnifying glasses to determine if the seal had been removed or burned. They again weighed the payload to ensure it had not changed.

Lockheed presented a plaque signed by Kelly Johnson and his staff saluting the Air Force maintenance personnel headed by Maj. Don Donohue for seven records to Lockheed’s one.

I would be remiss if I didn’t discuss Blackbird speeds a bit further. As stated above, the president restricted the YF-12 to 2,070.101 mph and 80,257.65 feet as a new world record. The iconic SR-71 Blackbird, at 85,000-feet and 2,112 mph, is known for being the official record holder for the fastest jet-powered, piloted aircraft of all time. The CIA’s super-secret A-12, the first in the Blackbird family, flew at 95,000 feet and 2,221 mph. Faster and nearly a mile higher flying than the SR-71. The A-12’s secret existence prevented it from making these speeds and altitudes official. Logically, the speed superiority is beyond reproach. When the Air Force, using the same engines, converted a one-seat A-12 to a two-seat SR-71, adding a person and all the necessary life support equipment, the added weight cost the plane both speed and altitude.