Written by Jerri Bergen, with Torrey Larsen, June 2006 May-2007
Torrey Larsen, formerly of hangar 219, passed away recently, leaving us saddened by our loss, and the familiar sight of his blue van trolling Cable Airport. Torrey had a long and fruitful career at Lockheed Aircraft as a Flight Test Engineer, and especially enjoyed sharing his recollections of the flight test operations of the YF-12A, a predecessor to the SR-71.
What follows is an excerpt of an article that Torrey and I had planned to publish in The Journal of the American Aviation Historical Society. Although not completed, it will give you just a taste of the varied and intricate assignments that resulted in many of the wonderful hangar conversations Torrey and I shared as I worked in our hangar (218) next door.
The fastest, highest flying reconnaissance aircraft in the world designed in the late 1950s by the Lockheed Corporation also became the highest, fastest air-to-air interceptor in the world, then and now. The A12 Program proved concepts of Mach 3+ flight at operating levels exceeding 80,000 feet, while its variant the YF12A program successfully proved the design also provided the supreme ‘look-down-shoot down’ capability unmatched then or today. Torrey Larsen, senior Flight Test Engineer for the YF12, and others remember the many obstacles overcome and the validation of its hard-earned technical success.
The YF12A was a progression of the A12 program, created by legendary Lockheed Aerospace design leader Kelly Johnson, Vice President and first Director of the Lockheed Advanced Development Company in Burbank, California. In 1955, Lockheed had provided the US government with a high flying spyplane, the ‘Dragon Lady’ U2, that collected detailed fly-over military data until May 01, 1960, when Major Francis Gary Powers was shot down near Sverdlovsk, Russia. Overflights of Russia ceased, but other world conflicts continued to raise the need for valid, accurate reconnaissance information.
YF12 Specifications: Wingspan: 55 feet 7 inches Maximum weight: 127,000 pounds Wing Area: 1,605 square feet Maximum speed 3.2 mach Length: 105 feet, 2.5 inches Service ceiling 85,000 Height 18 feet, 3 inches Rate of climb Classified Empty weight 60,730 pounds Maximum range 2,250 miles (not inflight fueling)A higher and faster flying aircraft was needed to outrun the increasingly powerful surface-to-air missile threat. Efforts were initiated to design aircraft with much lower radar signatures, thus lower targetability. Lockheed’s designated ‘A- 11’ design proposal was selected, and project OXCART began (the A11 didn’t become the A12 officially until after the program was completed.)
In the meantime, the Air Force contracted with Lockheed to develop three interceptor versions of A-12 on October 31, 1960 . Johnson realized the potential of the A12 airframe, powerplant and flight characteristics that could outperform the Air Force’s existing or proposed air defense interceptors Johnson was directed to equip an A-12 variant with a missile and radar system.
The YF12A had many of the same characteristics as the A12 with some significant differences. And Torrey was happy to go into details of each and every one! But here’s the basics (written for someone without 40 years of engineering background..):
The YF12A had it’s forward fuselage ‘chines’ or lateral fins cut back to allow a 40 inch radar scanning dish. Existing camera and surveillance equipment bays were re-designed into three missile bays . Design computations of airflow around the missile bay doors opening at Mach speeds indicated significant directional stability degradation. This destabilizing force would multiply as Mach increased, so designers added a folding ventral fins centerline on the fuselage and smaller ventral fins on either engine nacelles, to provide more directional stability at Mach speeds. The large ventral fin dropped well below landing gear clearance. Thus it was designed with reciprocal action to the landing gear; or, when the landing gear was up, the central fin lowered, and when landing gear was dropped, the central fin retracted.
The pilot’s seat was also raised for better visibility, and a Radar Systems Operator (RSO) seat was installed further back into the forward fuselage.
The right front bay was comprised entirely of flight test equipment and radar equipment controlling the AN/ASG-18 missile, made by Hughes. An Airborne Observation (AO) panel was installed containing a bank of lights that designated ‘on/off’ status of the cockpit instruments. A 35mm color camera snapped pictures every 2.3 seconds, capturing instrument status. At times, disagreement occurred between flight test engineers and pilots on instrument readouts, and if the AO was activated or not. Torrey solved the problem by including in the camera view an ‘on/off switch of the AO camera itself and a clock, quelling any disputes on instrument readings.
Torrey Larsen joined Lockheed after completing the Aerospace Engineering program at California Polytechnic University at San Louis Obispo in the winter of 1962. Prior to college, Torrey spent 3 years in the Army, gaining an Airframe and Powerplant (A&P) license. He maintained H21 helicoptors in the 153rd Field Maintenance detachment at Davidson Army Airfield, Fort Belvore, Virginia. At the Davidson Army Airfield Torrey managed sheet metal and rotor blade repair, engine overhaul anlysis and high speed runups. for functional flight checks. He was also responsible for verifying the unit’s helicopter rigging controls.
The Davidson Army airfield was detailed to transport high level military personnel between the Pentagon and classified retreats. This tour of duty necessitated all personnel to pass a rigorous security and background check. Lockheed counted this a valuable asset, as they sought to implement one of the most secret military projects of the decade. Still, Torrey had to go through additional security checks.
Torrey began work in Burbank in March of 1963, building test plans for several ground systems tests for the A12 aircraft. . A key initial focus was the confirmation of the placement of fuel pumps, based on center of gravity, the aircraft’s cruise angle of attack and other factors. All aircraft systems required pre-flight tests, that included creating test environments, documenting test procedures, and coordinating appropriate ground equipment.
In the early 1960s, Lockheed had several aircraft designs in some phase of design,test or production. Lockheed’s Burbank facility was searching for qualified flight test engineers, with few found to have relevant skills & experience to plan for, test and manage the vast amounts of complex flight data collected from numerous design tests.
Soon after hiring in as an associate flight test engineer, Torrey was placed in a Lockheed flight test course, or the ‘Joe Weir Acadamy’to gain a detailed understanding of specific flight test engineering theories. Lockheed students designed flight test plans and requisitioned aircraft from the Lockheed fleet to implement their theories. Lockheed maintained two Queen Airs, a Twin Bonanza, and a Lockheed L60 (Cessna 180), Lockheed Constellations and a few helicopters for company transportation needs.
Young flight test engineering students reviewed their test plans with Joe Wier, Lockheed Flight Test department head, who had extensive experience in several Lockheed flight programs. Then they met with Lockheed test pilots like Ray Goudie, an airshow formation pilot who’d been a military test pilot in the Navy at Pax River and had Lockheed test pilot experience that went back before World War II. Sammy Mason, another Lockheed test pilot, had been a prominent barnstormer pilot of the 1930s in Southern California.. These and other talented pilots guided Lockheed aircraft through the student-designed maneuvers to test out theories in real life flight time.
Much classroom time was spent on properly collecting the details of the test results, to include all elements of the ships records, what should be contained, who should participate in collecting document data, and form and format for a complete ship’s record. Managers of the current test programs would be guest speakers. Flight test instrumentation, and how to interpret results were also covered. The fifteen week course was a comprehensive, synthesized immersion into the intricate, creative world of Flight Test.
Torrey then moved into the centralized Flight Test Engineering team, under management of Larry Bohanan, Division head. A chance meeting in an engineering building hallway with Hank Stokham, head of the YF12A Flight Test led to a flight test engineering position on YF12 program reporting to Ted Chanaurd, Group Engineer. Flight tests were scheduled to begin within a few weeks.
First flight was scheduled for August of 1963, in Groom Lake, Nevada. Torrey and other flight test employees arrived at Groom Lake from Burbank via a Lockheed Constellation a few weeks prior to set up offices, test equipment and get themselves settled in. They would be living onsite for the duration of the flight test program. YF12A personnel rooming at Groom Lake numbered about 35 - data analysts, test engineers, communications specialists, design engineers, production personnel, management and administrative staff. The total population at the facility was much larger.
The YF12A flight test office was a small lean-to adjoining one of the large hangar bays. Nine employees shared the approximately 12 x 30 foot shed. Torrey eventually moved his desk underneath YF12A delta wing , to better track and manage the fast-paced engineering change traffic. One side of the lean-to included a large plastic window, allowing radar tests between the flight test lab and the aircraft sitting in the hangar nearby.
Living quarters were austere. YF12 A employees shared rooms in small bunkhouses situated 200 yards from the flight line. In between the bunkhouses and the hangars was the mess hall. It was routine to get up at 5:30am, eat a hot breakfast enroute to the hangar and not return until 11:00pm, as everyone was on a 16 hour shift. A Lockheed Constellation made regular ferry trips between Groom Lake and Burbank, shuttling non-essential employees home for the weekend. Employees finishing schedule-critical jobs or performing time-sensitive ground tests (such as missile firings) stayed over weekends.
Torrey maintained the integrity of engineering work order changes, critical to ensuring the configuration of the aircraft was documented, and used as the basis for any changes. Kelly Johnson insisted on drawing release systems that were flexible and allowed for quick changes. Work orders could be updated several times per day as engineering design fixes were implemented. To reduce the opportunity for work order mixups, Torrey maintained sole responsibility for work order change authorization, resulting in most weekends being spent at ‘The Ranch’.
A number of the prime objectives for the basic airframe had been proven out in the A12 program. The YF12A test plan then focused on tests of the airframe and new missile systems integration while spot checking flight test elements of the A12 program
The airframes officially moved from the Design phase and prototype to the Flight Test phase when the aircraft was physically moved to Groom Lake from production facilities in Burbank. However, the airframe didn’t arrive in any shape to start actual flight test activities. Ship 1001 for example, didn’t have it’s air conditioning units installed, and fuel tank sealings and curing had yet to be completed. The major gear box for both left and right hydraulic generating systems were not yet installed, as persistent design problems caused delays. Mock up units were used to fabricate the tubing between the new hydraulic units. When the actual generating systems arrived, the tubing required extensive rework to fit. Boxes of parts continued to trickle in for installation on the flight test aircraft even while flight plans were being developed.
Flight tests of YF12 were initially performed at Groom Lake, Nevada, along with the active A12 program. First flight of the YF12A, tail number 60-6934 (ship number 1001), flew on August 7, 1963, by Jim Eastham, chief pilot of Lockheed’s Skunk Works. The second, 60-6935 (ship number 1002) made its first flight on November 26, 1963, flown by test pilot Lou Schalk, also of Skunk Works. The third YF12A (60-6936, ship number 1003) first flew on 13 March, 1964, flown by Skunk Works pilot Robert J. Gilliland
Official first flight was carefully planned, with Torrey Larsen (as Senior Flight Test engineer) in the control tower to lead the operation. Kelly Johnson was present observe, as was his custom for all first flights). Systems Engineer, Harry Hahn was present in the event of on-board problems. Airframe 3964 (ship 1001) was fueled with and its J58 engines ignited on the flightline. Preflight check of aircraft systems took about 30 minutes, while engines quickly heated to over 500 degrees. Any excessive time on the runway would result in costly engine overheating, to be avoided under any circumstances. The initial test flight went flawlessly, and Torrey received kudos from Kelly Johnson himself for the excellent preparations.
The first 13 test flights of ship 1001 were accomplished in about two months. Flight test objectives for each flight were defined by the master test plan and input from prior flight tests. The final test card for each flight was confirmed with the senior test engineer. Once confirmed, the master test card was duplicated and the copy went to the Flight Test Department Head and then to the flight analysts. A preflight briefing was always held with the pilot and the flight test engineer confirming the pilot’s understanding of the functions. After the first 13 flights, Torrey Larsen handed over flight test engineering duties for ship 60-6934 to another Flight Test engineer while he transferred his flight test activity on the second ship (60-6935) now ramping up its flight test schedule.
Test flights in the YF12A were focused, precision effort for all concerned. The pilot and RSO had sometimes hundreds of test elements to cover, documented on 10-inch wide rolls of test paper, fed through their pilot’s kneeboard. A standing joke ensued that the flight test wasn’t a real day’s work unless the test plan checklist was as tall as the pilot…
Flight test time was precious, every moment was used in collecting, testing and re-testing design or flight performance elements. It was imperative to acquire a clear, accurate accounting of every aspect of the flight. Torrey Larson would meet the pilot and RSO at the flightline with the Personal Equipment Van (PEV) to reduce distractions. A strict rule of crew isolation was instituted to ensure the pilot and RSO debriefed their perceptions in a methodical, consistent fashion after each flight, before engaging in communications that might color their memory of flight activity
While Torrey remained with the YF 12A testing at Groom Lake through the fall of 1963, Kelly Johnson maneuvered through the procurement politics of Washington. Lyndon B. Johnson was briefed on the YF12 program a week after taking office. The program was still operating at the highest levels of secrecy when Johnson held a press release on February 29, 1964 stating in part “The United States has successfully developed an advanced experimental jet aircraft, the A-11, which has been in sustained flight at more than 2,000 mph and at altitudes in excess of 70,000 feet. …..Several A-11 aircraft are now being flight tested at Edwards Air Force Base, in California’. At this time Senator Barry Goldwater, in his bid for the presidency, was criticizing Johnson for not continuing to develop the United States’ jet aircraft capability. Project managers of the YF12A program had known about the potential for a press announcement. Kelly Johnson had drafted the release, but it was unclear when or if the President would make the statement.
Torrey and the entire Flight Test organization was put on alert that the YF12A program may be moving to Edwards, and that an announcement by the President was imminent. On the morning of February 29th, 1964, Torrey and Kelly Johnson were in the control tower while Ships 1001 and 1002 idled on the Groom Lake runway. A small, low-power radio receiver in the control tower was tuned to Johnson’s public address, but most of it wasn’t audible through the static. The tower radio operator, using a much higher power radio receiver at the base of the tower relayed the President’s message over the public address system. At the end of the radio announcement the operator added ‘we better be on our way’. A few moments later Kelly gave the directive ‘lets go’ - and the aircraft were released for the short flight to Edwards and the public reception assembling there.
Shortly thereafter, transport aircraft arrived to pick up packed boxes and transport the rest of the program down to the Palmdale facility. Torrey and other YF12A employees were moved to housing off base in Palmdale and the Rosemond area. By this time Torrey had been transferred to oversee the flight tests of the second YF12A, ship 1002.
With the YF12A program now public knowledge, military brass, before unfamiliar (or unaware) of the program descended on Palmdale to check out the outrageous claims made in Johnson’s statement. Several YF12A test flights incorporated short flights to familiarize military command personnel with the YF12A’s immense capabilities, and report back to the Pentagon the program progress.
Colonel Fox Stevens, a former Air Force pilot was assigned a minor navigational system flight test. Several training briefings were held with Colonel Stevens to familiarize him with cockpit controls and YF12A flight characteristics. He was suited out and briefed for the flight along with his assigned RSO. Torrey created a basic flight test plan with directions to test the on-board navigation system (something like ‘Fly over Wendover, Utah, make a right, come home’). The way points to be recorded by the pilot to correlate the on board navigation system were large geographic points and would be easy to see from the air. .
Col. Stevens got lost however, and did not follow the flight path defined by the nav system. Colonel Stevens was tracked circling over eastern end of Bonneville flats, Nevada for some time. He was provided directional coordinates to return to base, and on the downwind leg, and requested permission for a touch and go. The YF12A burned an average 10,000 gallons of fuel per hour, per engine, using full afterburners. A planned fuel calibration test was scheduled for the next day, so it was unclear exactly how much fuel he had on board, even after calling out fuel system readings. Torrey directed the flight to land. The next day the YF-12A tanks were drained for the fuel calibration test, to find only 55 gallons of fuel remaining in all tanks (Colonel Fox Stevens went on later to pilot YF12A 60-6936 to world altitude record).
Actual flight test times were a tightly controlled secret. There had been evidence of unfriendly governments attempting to listen or look in on Groom Lake operations. The Control Tower would receive daily updates of satellite fly-overs, and periodically Torrey, along with others, would all dash outside to cover the aircraft and other airframes on the flight ramp to disguise their outline.
Russian trawlers routinely plyed the waters off Point Mugu up to the Monterey Penninsula, pointing powerful listening equipment towards US military bases. Implementing a test flight included coordinating the planned flight path with several other government agencies to ensure secrecy and airspace safety. The FAA had an assigned controller at Palmdale with appropriate security clearances to handle Groom Lake flight test activity. Because of the high speed nature of the test flights, it was impractical to keep very large areas of air space clear. The FAA created the Moving Intercept Training Area (MITA), that would ensure the YF12A was at least 10 miles from any other traffic when below 39,000 feet. Flight tests above this altitude were less concerning, as the YF12A would not encounter non-Lockheed aircraft.
On one occasion, prior to a planned missile flight test the program was informed that a Russian trawler that was tracked earlier moving north away from Point Mugu, had now turned a 180 degree turn south and was steaming at very high speeds back down toward the coast of Nicholas Island, immediately under the planned flight path. Fortunately, the YF12A program had the support of the Navy, who upon request would deploy P2Es and P3s configured with electronic scrambling equipment, to disable any listening devices that might be present.
At the time of the YF12A’s flight test program, radar tracking of the aircraft’s position was triangulated between three 30 foot radar receiving disks located at Edwards AFB in Palmdale, at Point Mugu Naval Station and the China Lake military installation in Ridgecrest, California. These disks were capable of tracking how far away an object was with a high degree of accuracy. Persistent location errors were present, however, and the flight program was forced to use pilot visual references to confirm aircraft positions. Later, it was discovered (during the SR71 flight test programs) that the recorded physical location (latitude, longitude, elevation) of the transmitter and receivers was based on imprecise 1800’s era geographic surveyor data, resulting in radar tracking positions inaccuracies of up to several miles. The existing radar system was recalibrated using satellite based GPS points at all three military sites. Accuracy increased to place the aircraft’s position within inches of actual.
Kelly Johnson’s design philosophy of ‘keep it simple, stupid (KISS) extended to flight test operations as well. Nothing additional was designed or built in the program if something existing would do. For example, a 1930s era temperature sensing device, known as a Brown Recorder, was used to collect temperature information from points around the airframe.
The Brown Recorder utilized thermocouples – two dissimilar metal wires fused together and attached to an insulated box (‘bath’) containing about 12 pounds of ice chips. The ice water was used as a constant temperature reference of 32 degrees. Wires extended from the ice bath to points on the airframe. The different metals created a current differential at the measurement point (on the wing, under the missile bay doors, etc.), which was measured by transducers of the Brown recorder and compared with the reference temperature of the ice bath. One of Torrey’s jobs was to ‘fill the bucket’ with ice chips prior to a flight test.
Flight tests were always accompanied by a chase pilot to assist in monitoring aircraft performance. The YF12A chase planes were usually F104 Starfighters piloted by Lockheed test pilots. F104s could fly just under mach 1.0. On one flight test, the chase pilot radioed in that the central ventral fin had sustained damage on the leading edge. Torrey, directing the test flight from the control tower, directed the chase pilot to get a better look before deciding to abort the mission. The pilot radioed back that the leading edge had been reduced by 7 inches. When Torrey asked how the pilot could confirm the missing segment with such precision, the pilot responded that he tucked up under YF12A and simply counted the screws of the remaining leading edge material (at over 600 miles an hour!).
The Air Force brass had yet to see the YF12A perform in it’s primary interceptor role. Torrey and the YF12A team were told to ferry ship 60-6934 to Eglin Air Force Base, Florida for a live target demonstration. Torrey prepared the test plan and a few days before the live test did a ‘practice run’, successfully deploying the YF12A from Palmdale, California to sight a target over Florida. When Air Force brass phoned from Florida to determine their readiness, the Flight test team responded in the affirmative, they’d already performed a successful test, launched from the Palmdale facility. The response was a frosty “ it is impossible to deploy an successful missile assault from 3,000 miles away. Get out to Eglin, Florida for the demonstration!”
On April 25, 1966, ships 60-6934 and 60-6936, were taken to Eglin AFB in Florida for firing trials. Torrey, as lead flight test engineer, followed via a Lockheed Constellation along with other Lockheed and Palmdale Air Force personnel. Ship 60-6934 was prepped as the primary for the mission, with ship 60-6936 as backup. Torrey assisted Jim in preparing 60-6934 on the flight line. A Boeing QB-47 drone was circling off the coast at an altitude of about 200 feet off the water
Jim Eastham lifted off and set up the YF12A for a direct head-on hit. 10 seconds prior to missile launch, Jim radioed that there was a radar system failure, and the mission was called in. The awaiting Air Force, hearing of the malfunction, requested the back-up aircraft to deploy.
Torrey assisted with 60-6936 preflight as well. Several seconds before the second scheduled missile launch, the pilot announced a missile systems failure, and the mission was again aborted. After a quick review of viable systems on the two aircraft, Torrey and the flight team cannibalized the missile components from ship 60-6934 and placed them in 60-6936 and the trial resumed that day. (interview, T. Larsen)
The third attempt was successful. Jim Eastham, fired an unarmed AIM-47 against the QB-47 from 75,000 feet, from a distance of 120 miles away. The missile passed through the QB-47’s horizontal stabilizer; a direct hit.
Back at Palmdale, the YF12As maintained a steady flight test schedule, but the end of the program was drawing near. The Air Force had run out of money, even though Congress had appropriated funds for YF12B production three years in a row. Secretary of Defense Robert McNamara blocked the Air Force use of these funds for the YF12B, stating in a joint hearing of the Senate Armed Services Committee and Appropriation SubCommittee “ I felt quite confident that it is not necessary to appropriate money that can’t be justified for the weapon system itself, simply to keep the production line open”. Only three were ever built.
The YF12A, its predecessor, the A-12 and the superstar SR-71 have captured the world’s aviation imagination like few other aircraft families have. The YF12A Interceptor was and still is one of the highest performing interceptor aircraft yet built. In 1966 it was calculated that 93 YF12A Interceptors could defend the entire United States continental perimeter from any low-flying foreign bomber attack.
Upon retiring from Lockheed, Torrey continued his association with the famed Blackbirds, volunteering his time to design and orchestrate the physical moves of the SR71s out of storage in Palmdale to museums across the world. Torrey has provided all the structural design data and installation leadership for the mounting of SR71 ships all over the country, including the one installed in front of the Colliseum, Los Angeles.
Torrey was an accomplished pilot, having owned several types, including a Beech Staggerwing, a Bonanza and a Mooney M20A model. … any other stats, Tony?
We’ll miss Torrey, and his stories!