Category . LOCKHEED’S BLACK WORLD SKUNK WORKS

By the middle of 1963 only 21 out of the original 55 U-2’s remained, most having been lost over the years to various accidents. Mindful of the U-2’s performance degradation, brought about by heavier payloads and the inability of engine improvements to compensate, Kelly Johnson embarked upon an investigation into ways of re-establishing the aircraft’s performance. These began on 2 February 1965 and were referred to variously as the VU-2C or U-2N; in-house however, they were known as the CL-351. The emerging aircraft was one third larger than its predecessors and eventually became the U-2R.

On 19 September 1966, the Air Force approved the construction of eight aircraft, placing a further order for four additional U-2Rs, four months later.

Final assembly took place in Building 309/310 at Burbank, after which Article 051 (the prototype) was trucked to Edwards North Base, for its first flight, an event that took place on 28 August 1967 – at the controls was Lockheed Test Pilot, Bill Park.

By February 1968, the second U-2R was dispatched to North Base, where it was received by a CIA unit desig­nated Det G. By December 1968, all twelve aircraft had been delivered and equally split between the ‘Agency’ and the Air Force. In keeping with other Air Force projects, the ‘Senior’ codename given to the U-2R programme was Senior Year.

Throughout the 1970s, U-2Rs were put to work moni­toring the Middle East and Cuba. In Southeast Asia,

Above and below Following extensive flight testing the P&W J75 engine has at last been replaced on the U-2 fleet by the General Electric FI I8-GE-I0I. All aircraft have accordingly been redesignated U-2S. The new engine is 1.300 lbs lighter and 16 per cent more fuel efficient, enabling the aircraft to gain another 3,500 ft in altitude and increase its range by l,220n miles (or alternatively increase its boiler time). (Lockheed Martin)

OL-20 moved in July 1970 from Bien Hoa to U-Tapao, Thailand. Here a Melpur Commit sensor and datalink from the Sperry company was integrated into a U-2R, giving rise to the Senior Book, Siglnt programme. These missions were flown mainly at night in racetrack orbits high above the Gulf of Tonkin, from where the U-2 eavesdropped on Vietnamese national and air defence communications, transmitting the data, in real time, to a ground station at Nakhon, Phanom, on the Thai border. These flights provided simultaneous communication relay facilities to other US aircraft in the region. By January 1973, operations increased to round-the-clock and OL-20 was redesignated the 99th SRS. Siglnt coverage contin­ued to improve and expand, giving rise to Senior Spear – this entailed antennas being moved from the fuselage into specially adapted pods faired into the wing. Then came Senior Stretch, where siglnt data collected by the U-2 was relayed from the ground station up to satellites and onward to the National Security Agency (NSA), Maryland. As the war in Vietnam drew to a close, followed by the inevitable cuts in defence spending, U-2s of the 100 SRW were, in July 1976, consolidated into the 1 SRW, at Beale AFB, California.

In August 1976, U-2R 68-10336 deployed to RAF Mildenhall, sporting two super pods. The pods housed spiral antennas for Elint collection, in a programme code­named Senior Ruby. As the decade drew to a close, the growing disparity between the size of Soviet and NATO conventional forces in Europe worried many western political and military leaders. It was thought that little could be done on a conventional battlefield to halt a Blitzkrieg type of attack carried out by the Warsaw Pact. The only counter to this would be a NATO pre-emptive strike, directed at such forces as they massed for attack. But this would require accurate all weather surveillance, extending well beyond the East-West border, which could then be made available to field commanders in near-real time. The hi-tech answer was to co-locate a system called Precision Location Strike System (PLSS), which identi­
fied air defence radar and communications sites by homing in on their emissions, with a long-range, high resolution radar, being developed by Hughes, known as ASARS-2 – Advanced Synthetic Aperture Radar System (ASARS-1 was deployed on the SR-71). All of this digi­tised information could then be downloaded as required. With its additional capacity, high-altitude capability and proven long loiter time, the U-2R was the natural plat­form choice in which to site all of these ‘black boxes’. Furthermore, in a move designed to shake off the ‘spy – plane’ tag once and for all, it was agreed that the aircraft would be renamed the TR-1, for Tactical Reconnaissance. But as Kelly Johnson’s successor, Ben Rich, later remarked, “The press simply called it the TR-1 spvplane instead!”.

Twenty-five TR-ls were ordered in the FY 1979 budget, at a cost of about S550 million, including sensors and ground support equipment. In addition, a further ten aircraft were ordered ‘in the black’, these would retain their U-2R designation and supplement those surviving from the earlier build.

The first Air Force TR-1, 80-1066, was publicly rolled out at site 7, Palmdale, on 15 July 1981 and was flown for the first time by Lockheed Test Pilot Ken Weir on 1 August. In-flight development of ASARS-2 had been conducted utilising U-2R, 68-10336 and early test results were remarkable.

Precision Location Strike System operation required three TR-ls to operate as a team. Loitering at high alti­tude with Elint sensors which were data-linked to a ground station they enabled threat emitters to be

Below The U-2R/S together with the RC-135 (depicted is an RC-I35U, Combat Sent aircraft, used for technical ELINT collection, complete with bogus serial numbers applied to the nose and tail) are without doubt the most sophisticated air breathing intelligence gathering platforms in the western world. (Paul Cnckmore Collection)

pinpointed immediately by triangulation. This method side-stepped the problems of emitters shutting down before the direction-finding process, conducted by Wild W’easel aircraft, could be completed. A similar system, known as the Advanced Location and Strike System (ALSS), had been installed together with datalinks on all seven remaining Air Force U-2Cs, back in 1972; however, it was plagued with problems and cancelled. The sophis­tication of PLSS brought with it similar difficulties and after a series of delays, it too was cancelled, in the late 1980s.

Northrop’s XST entry was similar in appearance to that of Lockheed’s; its design had been developed from a computer programme called GENSCAT. This also had its origins in mathematical equations associated with the physics of optics. McDonnell Douglas had been the first to determine what the RCS thresholds for the competi­tion were likely to be, however they were unable to design an aircraft that could achieve anything like those

goals. With RCS results from both Lockheed and Northrop verging on the revolutionary, DARPA deter­mined that the program should be developed into a two-phase, full-scale, flight test demonstration. Phase 1 would culminate in a ground RCS evaluation of large scale models, following which one contractor would be selected to proceed with phase two: the construction and flight testing of two demonstration vehicles. The estimat­ed cost for the XST programme was 536,000,000 and this would be split between the successful contractor, the Air Force and DARPA. On 1 November 1975, Lockheed and Northrop were each awarded contracts of SI.5 million to conduct phase one of the XST programme.

In early April 1976, Lockheed received word that they had officially’ won that phase of the competition. However the outstanding results also achieved by the Northrop team caused DARPA to urge them to remain together. Shortly thereafter Northrop successfully submitted studies for a Battlefield Surveillance Aircraft, Experimental (BSAX) which became Tacit Blue – the highly successful flight demonstration programme that provided vital data for the subsequent B-2 bomber program.

Phase two of the XST programme was code-named Have Blue, and was initiated on 26 April 1976, when the Skunk Works were authorised to proceed with the design, construction and flight testing of two technology demon­strator aircraft.

Have Blue had three objectives:

1. Validate, in flight, the four low observability- signatures identified earlier in the programme, (radar, infrared, acoustic and visual).

2. Demonstrate acceptable performance and flying qualities.

3. Demonstrate modelling capabilities that accurately predict low observable characteristics of an aircraft in flight.

.Manufacturing was placed under the direction of Bob Murphy and the entire Engineering, Fabrication and Assembly of Have Blue was carried out in legendary Building 82 (birthplace of the F-104, U-2 and A-12).

Above left Lockheed chief test pilot, Bill Park (in flight suit), was first to fly the Have Blue prototype HB1001. (Lockheed Martin)

Above Maj Norman ‘Ken’ Dyson was recruited into the Have Blue program whilst serving as Director of the F-IS Joint Test Force. (Lockheed Martin) below НВІ00І received this ingenious three colour-three tone camouflage pattern to hide the facetting from uncleared ‘onlookers’. (Lockheed Martin)

Just three assembly tools were used on the project; wing, forward fuselage and aft fuselage. The sub assem­blies were all made on a tooling plate left over from where the main frames for the C-5 Galaxy had been machined. On the morning of Wednesday 16 November the prototype Have Blue (HB1001) was flown by C-5 from Burbank to Area 51, where it was reassembled and readied for a final series of pre-flight tests. On 1 December 1977, Bill Park completed HBlOOl’s maiden flight.

The first five sorties in aircraft number one were completed by Bill, who was chased on each occasion by Air Force Test Pilot Ken Dyson in a T-38. On 17 January 1978, Ken completed his first flight in the Have Blue prototype. All was proceeding well and on 4 May 1978, Bill had conducted 24 flights on HB1001 and Ken, twelve. However, whilst returning to Area 51 that day,

Bill was involved in a landing incident which damaged one of the aircraft’s main undercarriage legs. Retracting the gear and going-around for another landing attempt Bill discovered that the damaged leg would only half extend. Despite several attempts to free the jam by pounding the other main wheel on the runway, it stead­fastly refused to budge. As fuel depleted, the decision was made to climb the aircraft to 10,000ft and for Bill to eject. However, on the climb, the aircraft ran out of gas and Bill was forced to eject, during the course of which he hit his head and was knocked out. Still unconscious when he hit the ground, he sustained back and leg injuries that forced an early retirement from test flying.

It would take a further six months to prepare HB1002 for its maiden flight; an event which took place early on the morning of the 20 July 1978. Ken Dyson recalls, “We

flew three flights to check the aeroplane out, then on 9 August 1978, we began to take the first airborne RCS measurements. І Пси against a ground based facility and on these first series of tests, they wanted to check-out the cross-section of the aeroplane nose-on, that’s with a look angle of zero. To achieve this, I climbed to a predeter­mined altitude and maintained a heading that would take me right over the radar test site. When I reached the test point, I configured the aeroplane in a decent, making sure my speed, angle of attack and rate of decent was exactly correct. I had to keep control movements to a minimum in order to provide accurate test data, so 1 switched in the autopilot. Well, as soon as I did that, the nose went right and the wing rolled slightly left. I later learned that Ben Rich, who was watching the test in the radar control room went crazy, asking, ‘What does that goddamn Air Force pilot think he is doing! Is he deliberately side-slip­ping the aeroplane to screw-up our test results?’ I decided to switch-off the autopilot and fly manually, something we’d planned not to do, because the test engineers didn’t think the necessary tight parameters could he achieved manually. Well it seemed to work pretty good, and after that, 1 flew all the tests manually – we never did resolve the problem with the autopilot. Virtually every flight in aeroplane two was associated with RCS measurements and if we weren’t measuring radar returns, we would be flying the aeroplane against operational systems to see if they could see us. To my knowledge, none did.”

On 29 June 1979, Dyson air aborted HB1002 shortly after take off, following a fluctuating hydraulic pressure reading. He continues, “On 10 July, we flew again and the aeroplane was OK. The next day I got airborne and had the chase aeroplane look me over, everything was OK, so I flew outbound to get to a point to run against an F-15 Eagle, to see how it performed against us. I was

Above HBI002 was the RCS test vehicle and was flown throughout its life by Ken Dyson. Its external appearance differed from the prototype: gone is the instrumented nose – boom and the drag ‘chute receptacle. (Lockheed Martin)

Below HBI002 accumulated 52 test sorties before being lost on 20 July 1978. (Lockheed Martin)

just short of the designated turn point, when 1 noticed the same hydraulic system begin to oscillate, again in the downward direction. 1 thought well, that’s the end of this flight and turned back. I started to tell test control about my problem, when I got a fire light. After pulling the pow’er back, and telling them of my troubles, I shut the engine down. All this was in short order. I had the aeroplane pointed towards home plate and configured at the right speed for single engine operation (it was not a

Above Despite initial skepticism over the ‘Hopeless Diamond’ concept, Dick Cantrell and his team of aerodynamicists worked tirelessly to ensure that the F-l 17 retained the smallest RCS and remained aerodynamically viable. (Lockheed Martin)

Below As president of the Lockheed Martin Skunk Works, Ben Rich was the driver behind the stealth concept; he passed away on 5 January 1995. (Lockheed Martin)

good performer on a single engine, not much thrust, and a lot of drag). I was coming home somewhere between 20 and 25,000 ft. Shortly after that, the remaining hydraulic system began to oscillate in a downward direction and I knew that was not good for our unstable machine. Just about the time the remaining hydraulic system went to zero, the plane pitched violently down, something like 7 negative ‘g’s, it then pitched up, the pitch rates were just eye watering, something only an unstable machine could do. I was somewhere around 225 knots and above 20,000ft and the aeroplane was tossing me up and down and actually got near vertical nose down and near vertical nose up. I began to try and reach for the ejection seat ring that was between my legs. I got my hand on it and pulled. The canopy blew off, the seat went out and I found myself floating under a ’chute at about 20,000 ft.” As Ken slowly descended by ’chute, the pilot of the F – 15 with whom he had planned to conduct further tests began orbiting above. Col Norm Suits, the Director of the F-l 5 Joint Test Force, saw the stricken Have Blue aircraft impact the ground and shortly afterwards, spotted two unauthorised cross country vehicles heading towards the crash site. Although the vehicle’s occupants were probably intent on performing their public duty and offering help and assistance to any survivors, the highly classified nature of the program and the materials used in its design couldn’t be compromised. Acting on his own

Left Unstable in all three axes – pitch, roll and yaw – it is essen­tial that this fly-by-wire platform receives accurate air data at all times. Therefore this unique four probe system was devel­oped. (Paul Crickmore)

Below Although ice encrustation was not an issue on the Have Blue research vehicles, much time, thought and effort was devoted to the problem on the F-117, before this simple wiper blade was developed. (Paul Crickmore)

Left The F-l 17 is at its most stealthy head-on, 25 degrees look – down and 25 degrees look-up. Note suck-in doors located above the intakes to supplement air flow at low engine oper­ating speeds. (Lockheed Martin)

initiative, Norm began a series of extremely low passes at the vehicles to deter their drivers from closing in on the wreckage. Just how low these passes were, can only be judged from the fact that he succeeded in his objective!

Ken continues, “I had noted my take off time, and while hanging in my ’chute I noted that ten minutes had elapsed from take-off. I watched the unstable machine flip flop slowly it seemed, as it descended vertically below me and I saw it hit the ground and erupt into a ball of fire, it still had a lot of gas on board. It took me quite a while to make my parachute descent down to the desert floor, after landing (that was my first and only jump to date), I again noted the time, I had been in the parachute for ten minutes”.

The cause of the crash was determined to be an engine exhaust clamp, which had become loose, allowing hot exhaust gases to enter the right engine compartment.

This had triggered the fire warning light, and as the temperature built up, first the left and then the right hydraulic lines failed, which in turn caused a complete loss of control.

Fortunately the program was within two or three sorties of its planned completion, which officially ended in December 1979. Having achieved all its test objectives, the Have Blue programme can be categorised as a stun­ning success.

With ad hoc deployments to RAF Mildenhall of both the U-2R and SR-71 having been made during the late 1970s, Det 4 of the 9th SRW was established at the base in April 1979 with a single U-2R. Its mission was purely Siglnt, however, as the year came to an end, 68-10338 was replaced by 68-10339. This latter aircraft was equipped with both Senior Ruby and Senior Spear, there­by combining both Elinr and Siglnt on a single airframe. Det 4 continued to fly the Siglnt mission, codenamed Creak Spectre until February 1982, after which the role was taken on by TR-lAs of the newly activated 17th Reconnaissance Wing, at RAF Alconbury. In March 1985, the 17th RW received three more TR-lAs together with the ASARS-2 capability. A major milestone was achieved by Lt Col John Sander on 9 July 1985, when he flew the first operational ASARS-2 sortie, marking a new begin­ning in battlefield reconnaissance. The wing was eventually assigned twelve TR-lAs before being deactivat­ed in June 1991.

In June 1977 the Air Force set up a special project office in the Pentagon; its objective, to exploit low observable technology then being demonstrated in phase one of the

XST program, and in addition, to initiate conceptual studies into a manned strike aircraft program, referred to as the Advanced Technology Aircraft (ATA) program.

Two sets of preliminary requirements for the ATA were developed: ATA ‘A’, a single scat attack aircraft, with a

5,0 lb payload and 400 n mile range; and ATA ‘B’, a two-seat bomber with a 10,000 lb payload and 1,000 n mile range.

An SI 1.1 million concept definition contract was awarded to the Skunk Works on 10 October 1977, for a one year study, based on these two sets of requirements.

As assimilation of the two proposals continued, it became increasingly apparent that ATA ‘B’ (despite being strongly favoured by Strategic Air Command, following cancellation by the Carter administration of the B-1A), w’as in the upper right corner of what was at that time considered realistically achievable.

Consequently in the summer of 1978, Air Force officials decided to terminate further studies involving ATA ‘B’ and instead, opted to proceed with ATA ‘A’ into full scale development (FSD).

Covert funds were established, and key individuals serving on various government committees were briefed on the programme. On 1 November 1978, production was authorised, the programme accorded the code name ‘Senior Trend’ and Lockheed were awarded a S340 million contract to cover the cost of building five full – scale development aircraft, plus, provide spares, support and flight testing (this amount did not include the cost of purchasing the aircraft’s General Electric engines).

The production timescales for this revolutionary aircraft program were tight; its first flight was planned for July 1980 – hence the last three digits of the prototype’s serial number, 780. Initial Operational Capability (IOC) was to be achieved in March 1982, with a planned production run of twenty aircraft. Construction of FSD1, the prototype F-l 17A, (Aircraft 780) commenced at Burbank in November 1979.

Technical Specifications

The F-117A Nighthawk is a survivable interdictor; the determinant in achieving this goal has been the develop­ment of Very Low Observable (VLO) techniques. To confound the principal detection medium – radar – design focused upon producing a low radar cross section (RCS). The reduction of an aircraft’s RCS to levels that would provide an explicit operational advantage had been the ‘holy grail’ for many military aircraft designers since the latter stages of World War Two.

Over subsequent years, development work had, by and large, been focused on producing materials capable of absorbing incident radiation to varying degrees. Although the use of Radar Absorbing Materials (RAM) certainly achieved a reduction in RCS, this was not enough to gain ‘an explicit operational advantage’; that could only be achieved when designers were able to build a shape both capable of performing an operational mission and produc­ing an RCS lower by several orders of magnitude than any current conventional aircraft. It was here that the odds were definitely stacked against the designers, as perfectly demonstrated by the radar equation which basi­cally states that, ‘detection range is proportional to the fourth root of the radar cross section’. That is to say, in order to reduce detection range by a factor of ten, it is necessarv to reduce the target aircraft’s RCS by a factor of 10,000, or 40 dBs.

Having established the required RCS signature levels from various look angles, together with the overall shape required to meet those goals, it then becomes necessary to consider other aspects of the aircraft’s design that will impact on RCS values. For a conventional jet aircraft, these include the air-intake and exhaust cavities, the aircraft’s cockpit, etc. Thus to prevent radar energy

Above All sixty F-l l7As were constructed within the Skunk Works facilities at Burbank. (Lockheed Martin)

Be/owThe F-l 17 is powered by two General Electric F404-GE – FID2 engines. (Lockheed Martin)

reflecting back from numerous corner reflectors inside the cockpit, the F-117A’s cockpit windows are metallised, much like metallised sunglasses; allowing the pilot to see out, but to all other intents, performing as a facetted panel in relation to electromagnetic radiation, reflecting energy away from its source.

The RAM coating applied over the rest of the aircraft was originally made up of 8 feet by 2 feet sheets (desig­nated BX210), which were glued onto the aircraft’s surface like linoleum tiles. The process was extremely

time consuming and expensive, costing S750,000 dollars just in labour to apply the material. As a result, a computer controlled spray coating was developed, which is environmentally safe, bonds satisfactorily to the aircraft and preserves the required radar attenuation characteris­tics. The original compound was known as BX199, but its durability and maintainability was improved upon and it evolved

In addition to producing a low RCS, the F-117A designers also paid good attention to reducing electromag­netic emissions and infrared radiation from the aircraft’s hot parts. An important feature regarding design for low observability is that in general, the design of an aircraft does not have to be compromised to negate the different ‘observables’. For example, if something is good for reducing radar returns, it can generally be made good for reducing infrared returns and vice versa. It was therefore appropriate to shield the exhaust nozzle for both radar and infrared reasons.

Range specifications of ATA ‘A’ dictated planning for the aircraft to be in theatre, which immediately identified the principal radar types to be deceived in order to significantly enhance survivability. These were airborne intercept and SAM radars, which typically operate on a wave length of between 3 and 10 centimetres. It was soon determined that flying at supersonic speed didn’t enhance survivability. Indeed, flying at high subsonic speeds actu-

Above Taken during a training sortie in the flight simulator, the cockpit layout is pre-OCIP phase 3. (Lockheed Martin)

Below The current, post-OCIP phase 3 cockpit includes an active liquid crystal display, incorporated in the Heads-Up Display (HUD). (Lockheed Martin)

ally increased survivability by reducing a defender’s abili­ty of detecting, and tracking the aircraft using infrared systems. It was therefore decided that the platform would be powered by non afterburning engines, which also reduced airframe temperatures, further lowering its IR signature.

Optimum weapon effectiveness was achieved by placing the aircraft at medium altitude, which, for a subsonic aircraft, touting a modest performance envelope, would be utter suicide – were it not for stealth. The aspect which presents a defender with the greatest chance of a success­ful intercept is the frontal zone. If the threshold of detection, by radars using wavelengths of between 3 and 10 cm, can be foiled to a point where the aircraft is just one minute flying time (about ten miles), from the radar head, then there is a good chance of avoiding a successful intercept. Pulling all the strands together therefore, an F – 117A, flying at an altitude of 12,000 feet and 500 knots, will achieve that one minute detection goal parameter by being at its most ‘stealthy’, head on, 25 degrees look down, and 25 degrees look up.

Powered by two General Electric F404-GE F1D2 two shaft, low-bvpass-ratio turbofans the F-l 17A Nighthawk

Right Target acquisition is achieved using this Forward Looking Infra red (FLIR) turret. As the ‘look-angle’ increases, the target is ‘handed-off’ to the Downward Looking Infra red (DLIR) turret, located within the aircraft’s underside, for final target tracking. Together, the two units are referred to as the Infrared Acquisition and Detection System (IRADS). (Paul Crickmore)

Below The F-1 17 is capable of hauling a wide variety of hard­ware, including the B61 nuclear weapon. (Lockheed Martin)

has a maximum sea level thrust rating of 10,8001bs. The engine gearbox drives the main fuel pump, the oil pump assembly, the engine alternator and the PTO shaft, which powers the Airframe Mounted Accessory Drive (AM AD). Total fuel capacitv is approximately 19,000 lbs or 2,800 US gallons of JP-8.

Senior Trend’s original avionics package was based around three Delco M362 F computers with 32k words of 16 bit core memory, as used in the F-16. However, in 1984, its avionics architecture was the subject of a three phase Offensive Capability Improvement Program (OCIP). Phase 1, the Weapon System Computational Subsystem (WSCS) upgrade program was initiated to replace the Delco M362F’s with IBM ЛР-102 MIL-STD-1750A computers. These new units boosted the capability of 1 million instructions per second, 16 bit CPU with 128k words of 16 bit memory expandable to 256k.

Phase II of OCIP, afforded greater situational aware­ness, and reduced pilot workload, by allowing a 4D Flight Management System to fly complex profiles auto­matically, providing speed and time over target (TOT) control. Also included in this phase was the installation of Colour Multi functional Display Indicators and a Digital Tactical Situation Display or moving map; a new Data Entry Panel, a Display Processor, an Auto Throttle System and a Pilot Activated Automatic Recovery System (PAARS).

OCIP phase III saw the replacement of the ageing SPN-GEANS, INS system, with a new Honeywell H – 423/Е Ring Laser Gyro (RLG). The original acronym for this programme was to have been RNIP, which stands for Ring Laser Gryro, Navigation Improvement Programme. However, the system was supplemented with a Rockwell – Collins Global Positioning System (GPS) thereby giving rise to the title RNIP plus. The new INS vastly reduces
alignment time from 43 minutes for SPN-GEANS, to just 9 minutes and considerably enhances overall reliabili­ty, increasing the mean time between failure from 400 to

2,0 hours. In itself, the H-423 may not boost enhanced accuracy (still believed to be 0.12 n m/h), however, when used in association with GPS, the system represents a significant advance in navigational accuracy.

Just fifteen days after Iraq invaded Kuwait, two U-2s arrived at King Fahad Royal Saudi Air Base (RSAB).

One aircraft, 80-1070, was equipped with Senior Span – a system for uplinking data from the Siglnt collection systems to satellites, which then relayed the data across the globe. The other aircraft was equipped with SYERS –

Above and below The dorsal mounted pod houses a small dish antenna, enabling data to be transmitted to virtually any spot on earth, thanks to satellite relay. During the recent Balkan Wars, this development, known as Senior Span, integrated with Senior Glass (a combination of Senior Spear and Senior Ruby) enabled effective use to be made of all communications intelli­gence to a hitherto unattainable level. (Lockheed Martin)

the Senior Year Electro-optical Relay System. This system, developed by Itek, utilises a long focal length camera of 110 inches, with Cassegrain or folding optics technology, to focus an image on a 10,240 clement, Charged Couple Device (CCD). This digitised image, like ASARS, is then downloaded, in near-real time, to a ground station. On 19 August, both aircraft conducted their first operational missions near the Kuwait border. Four days later, two TR-ls arrived at King Fahad RSAB, from RAF Alconbury and on 29 August the first ASARS mission was flown. The new operating location at King Fahad was initially known as Location CH (Camel Hump), this was later redesignated 1704th Reconnaissance Squadron (Provisional) and was a component part of the 1700th Strategic Wing (Provisional). Ground stations for SYERS – codenamed Senior Blade, and for ASARS – know’n as TADMS – TR-1 ASARS Data Manipulation System, were located in a compound of the US Training Mission at Riyadh, where they were joined by stations to support RC-135 Rivet Joint Elint aircraft and J-STARS.

A fifth U-2R (another SYERS equipped aircraft) arrived

on 11 October, having been despatched from Osan AFB, South Korea.

From mid September, Iraq began launching MiG-25s in response to the U-2 border flights and henceforth they were provided with an F-15 MiG-Сар. The high level of systems integration derived from SYERS and ASARS ensured that within 10 minutes of a target being imaged by either system, its co-ordinate were available to the Theatre Air Control Centre. Indeed the system worked so well that when coalition attacks began, the nine U-2s (which soon became twelve) were virtually high altitude Forward Air Control (FAC) platforms detecting the posi­tions of SA-2, SA-3 and AAA sites as well as ‘Scud’ missiles.

When the ground war began on 24 February, a TR-1 provided an hour-by-hour image ‘commentary’ of precise Iraqi front-line armour and troop movements, thereby contributing directly to the speed of the coalition advance. In all, the 1704th RS flew 260 missions, totalling over

2,0 hours. It was calculated that they had provided 50 per cent of all imagery intelligence and a staggering 90 per cent of the Army’s targeting requirement.

In 1977, Lt Col Dave Ferguson commanded the 6513th Test Squadron, a unit which had its administrative head­quarters together with a small number of F-4s and T-38s at Edwards Air Force Base. However, the 6513th had a black side, seven of its other aircraft were involved in a highly classified programme known as ‘Red Hat’, these aircraft were MiG-17s and MiG-2 Is based up at Area 51. It was whilst carrying out his duties at ‘a remote test site’, that Dave met Bill Park. At that time, Bill was the Director of Flight Operations for the Skunk Works, but he hadn’t flown military7 jets since his involvement in Project Tagboard, the M-21/D-21 drone evaluations that had taken place nearly ten years earlier. Bill was gearing up to fly Have Blue and Dave was asked to get him re­qualified. This was achieved in a T-38 and through this initial contact, Dave flew the occasional T-38 chase sortie during the Have Blue programme. In 1978, Bill offered Dave a job on the Senior Trend Programme, which he accepted following his retirement from the Air Force in 1979. Earlier that same year Bill Park hired Harold ‘Hal’

Below Having been delivered by C-5 Galaxy from Burbank to Area 51, the F-1 17A prototype (FSDI) is undergoing final assembly. (Lockheed Martin)

Above The prototype’s serial – 780 – would prove to represent an over-optimistic first flight target date, with FSDI completing that task on 18 June 1981. (Lockheed Martin)

Farley in as the projects chief pilot, having poached him from Grumman. Tom Morgenfeld became the third pilot recruited, having worked prior with the YF-18 project development team.

In addition to contractor pilots, it had been decided that developmental together with category I and II, opera­tional test and evaluation (OT&E) of the F-117A, would be conducted by a Joint Test Force. Tactical Air Command (TAC), controlled testing and initially provided three pilots and two analysts. The third party involved in this ‘tripartite’ force, was Air Force Systems Command. They provided three pilots, four engineers and approxi­mately forty aircraft maintenance personnel.

To prepare themselves for the first series of flights in the F-117A, the team contacted Calspan, and asked them to provide a flight simulation programme based on aerodynamic data acquired through wind tunnel tests and Have Blue. As the programme was so highly classified, the data was delivered to Rogers Smith of Calspan by Hal, Dave, Tom and Bob Loschke, in a restaurant out at Newhall. During that meeting they detailed their require­ments from Calspan, without telling Smith what he would be simulating; all he had to work from was a set of aerodynamic data of the predicted flight characteristics of the aircraft in the landing pattern. Rogers Smith took the information with him to Buffalo, New York, to create a simulation which would be programmed into the Lockheed/Calspan NT-33A.

This aircraft enabled the predicted stability and control aspects of different aircraft to be simulated, allowing pilots to familiarise themselves with the likely characteris­tics to be encountered prior to their first real flights. In keeping with earlier Skunk Works, blackworld, aircraft development projects, flight testing would be conducted at the now legendary Area 51. On 1 January 1979,

Be/ow Chief test pilot Hal Farley, prepares to vacate the cock­pit upon successfully completing the F-117’s first flight.

(Lockheed Martin)

preparations at the remote site got underway to receive the latest guest.

Back at Burbank, the first production engine arrived in April 1980 and on 2 September, the first engine run was conducted. The complex design and engineering of the exhaust nozzle caused more than a few headaches and on 22 December, the team suffered the first of several nozzle failures. This led to further delays with to first flight. However, on 12 February 1981, an improv. d nozzle was fitted, which helped to eradicate at least some of the problems.

On 16 January 1981, a C-5 from Burbank touched down at Groom Lake, onboard was Aircraft 780, FSD 1 – the combined test team at last had an aircraft. It wasn’t until 18 June 1981 that Hal Farley was finally able to

take Aircraft 780 on its first flight, an event cut short due, yet again, to a temperature build-up in the exhaust section. However, the significance of this event was such that film footage shot during the sortie was edited at the test area into a one-minute sequence. It was then flown by special courier aircraft to Andrews AFB, and then taken to the White House, where it was viewed by President Reagan.

The second FSD aircraft, ’781, was flown for the first time by Dave Ferguson, on 24 September 1981. After completing just four sorties however, it underwent considerable rework, which included retro fitting larger interim tail units and a ‘production’ nose section, which,. after further tests, housed the Infrared Acquisition and Designation System (IRADS) units. In addition, an asymmetric, four-probe, production configured air data system was added.

It was decided to qualify the aircraft for air refuelling (A/R), early in the programme; the first such sortie being flown by AFSC test pilot Skip Anderson, on 17 November 1981. Once A/R qualified, the test program further accelerated, as evidenced by a flight completed by Hal in ‘780, just two days latter, which lasted 2.8hrs. The first night flight of an F-117A was completed by Roger Moseley flying Aircraft ’782 on the 22 March 1982; he flew the same aircraft on the 19 April 1982, successfully conducting the first night air refuelling.

Low Observability airborne testing of the F-117A was exhaustive. For ’783’s fourth flight, TAC pilot Tom Abel went airborne on 15 July 1982 to conduct IR tests of Senior Trend with the help on an NKC-135, an exercise repeated the next day by Pete Barnes. Four flights were then flown against an F-4 to evaluate the IR threat from air-launched heat seeking missiles. By 13 January 1983, Air Force pilots had flown ’783 on no less than 21 RCS

Above After ten flights, FSD I was grounded for over ten months, while larger tail units were fitted to improve direc­tional stability. The earlier desert-camouflage paint pattern was also removed and replaced by an overall, low-visibility grey scheme. (Lockheed Martin)

Below For a month FSD I had wing leading edge extensions added during an evaluation of its handling qualities. (Lockheed Martin)

and IR sorties. These included cued and uncued tests against the best US detection systems available, in addi­tion to ‘Special Category’ tests, flown against Soviet-made equipment ‘acquired’ through various means by the United States. One particular test, flown by John Beesley on a December 1982, included taking RCS measurements while the aircraft’s right bomb-bav door was open – a period when the aircraft is at its most vulnerable.

Aircraft ’783 continued to be the ‘fleet’s’ RCS work­horse throughout 1984, with analysis of the air-air threat continuing. On 24 April, an F-16 made four radar passes against the aircraft, two days later, thirteen radar passes were made by the Fighting Falcon.

By late July, F-15s, F-14s and an EF-111 had conduct­ed similar threat tests against ’783. Thereafter, it was utilised alternately between low observability tests and evaluations, and the integration of improvements made to the navigation and weapons delivery systems.

Aircraft ’784, FSD 5, was the dedicated IRADS test and evaluation ship, consequently its first 106 flights were made in pursuit of this task; after which on 23 September 1983, it was placed in temporary storage.

At the end of November 1984, the aircraft was disman­tled and moved, via C-5, from Area 51 back to Burbank. The operational limitations of an infrared targeting

Right and below Having qualified the F-117 for air refuelling from а КС-135 on 17 November 1981, Senior Trend was cleared to tank from КС-10 Extenders on 8 September 1983. (Lockheed Martin)

Above FSD5, serial ’784, the final developmental aircraft, completed its first flight on 10 April 1982. It is seen here drop­ping a 2,0001b GBU-27 practice bomb during separation trials.

(Lockheed Martin)

Left Initially equipped with the GBU-10, the Paveway II guidance unit corrected the weapons trajectory using full deflection commands to the canards. This had a negative impact on the weapon’s performance. (Lockheed Martin)

Be/ow The GBU-27 featured an improved Paveway III guidance section and when dropped for the first time by Jim Dunn, from 783, the inert weapon scored a direct hit on the 55 gallon barrel target, splitting it in half! (Lockheed Martin)

system with which to aim weapons (however accurately), was already fully appreciated. Consequently, Aircraft 784 underwent modifications to install a low observable radar system to conduct both ground mapping and target acquisition.

It was returned to Area 51 and from September 1985, until the end of the year 34 sorties totalling 45.5hrs were flown, during which time all aspects of the radar mapping and targeting system in ‘784 were evaluated: RCS of the antenna and radome; the ability of the system to perform the ground mapping task; threat evaluation during system
operation; system resolution including four sorties which were flown by 4450th TFG pilot, Maj William Aten (Bandit 164), enabling the system to be evaluated from a front line pilot’s perspective. Those involved in this evaluation have stated that the system was remarkable and incredibly stealthy.

However, it wras not deployed operationally for reasons of cost and on the basis that, to date, Senior Trend as a concept, had not been tested under actual combat condi­tions, something of a Catch 22 – stealth still had its ‘doubting Thomases’.

After a three year programme to improve the aircraft’s RAM coating, a compound known as BX185 was developed. A one – quarter scale model is seen being made ready for RCS evaluations at Lockheed’s Helendale test range. (Lockheed Martin)

When the test detachment at Area 51 changed command on 14 December 1983, John Beesley completed a fly-by in ‘782 patriotically adorned. (USAF)

Tonopah

Formed on 15 October 1979, designated the 4450th Tactical Group, and referred to as А-unit, the Air Force’s first operational F-117 unit was commanded by Col Robert “Burner” Jackson and would be located at the Tonopah Test Range, located northwest of Nellis AFB, Nevada. A security cover story for the blackworld unit was provided by twenty Ling Tempo Vaught A-7Ds and a small number of two seat A-7K. S. These were based at Nellis AFB and referred to as P-Unit. The 4450th Test Squadron (established on the 11 June 1981), was referred to as І-Unit and Detachment 1 of А-Unit, based at Tonopah, was Q-Unit. In addition to providing the ‘avionics testing’ cover story, the A-7s were used to main­tain pilot proficiency until F-117As became available and were also used as chase aircraft.

Supplemental to overseeing the construction program, Col Bob Jackson also set about recruiting the initial cadre of pilots, as A1 Whitley, at that time a Major, recalls:

“My interview occurred in late 1980 at the Nellis AFB, Visiting Officers Quarters. When the time came for the interview, I proceeded to the designated meeting place – Colonel Jackson’s room. When I knocked on the door, it opened slightly and Colonel Jackson asked to see my identification card. I produced it, the door closed, and a few seconds later he opened the door and said ‘Yes, y ou’re Whitley, come in’. In the next few minutes.

Colonel Jackson told me very little about a program

which would involve significant family separation, yet the opportunity to not only remain at Nellis AFB for another full assignment, but also the chance to fly the A-7 again. He didn’t say much more, other than I would have no opportunity to discuss it with my wife and that I had five minutes to make up my mind. With no hesitation, I said, ‘Sign me up’. Colonel Jackson said he’d be contacting me in the future on specifics. That was the end of the inter­view.” In the spring of 1981, Lt Colonel Jerry Fleming the Squadron Commander called Whitley and a couple of the new members of the unit to a remote, secure location in Area 11 (or Lake Mead Base) of the Nellis AFB complex. There, for the first time, they were shown photos of what they would be flying. Whitley remembers: “I was genuinely excited and honoured to be part of something that was on the ‘leading edge’ of technology.

I quickly added a new word to my vocabulary that would have a significant impact on the rest of my Air Force career – ‘stealth’.”

The original plan was that the unit should achieve initial operational capability (IOC), forty months after aircraft ’780’s first flight, which was scheduled for July 1980. Therefore Q-Unit, nicknamed the ‘Goatsuckers’, were expected to assume a limited operational role in November 1982. This was not achieved owing to various design and manufacturing obstacles. In fact, the first production aircraft, number ’785, didn’t attempt its first flight until 20 April 1982. As with the previous FSD aircraft, aeroplane number one, from Lot 2, had been completed at Burbank and flown via C-5 Galaxy to Area 51. There it had been re-assembled and following various ground checks, Lockheed test pilot Bob Riendenauer

In March 1991, the combined test force put this formation together; it depicts ‘781, 782, 783 and ‘831.780 had already been retired. (Lockheed Martin)

The first home for F-117 operations was Tonopah. Note the ‘drive-through’ barns, grouped in blocks of six. (Lockheed Martin)

advanced the throttles and began his take-off* run. The aircraft rotated as planned, hut immediately after lift off everything went horribly wrong. 1’he nose yawed violently, it then pitched up and completed a snap roll which left it on its back before impacting the ground. It was nothing short of a miracle that Bob survived, not so though aircraft ’785, which was totally wrecked. A post accident investigation established that the pitch and yaw rate gy ro input to the flight control computer had been cross wired.

In September, detachment 1 of the 4450th was designated the 4452nd Test Squadron and it was while the unit had a complement of just two aircraft that another milestone was achieved. On the night of Friday

15 October, Major A1 W hitley conducted his first Senior Trend flight and in so doing, also became the first operational pilot to fly the aircraft.

The sporadic nature of the delivery schedule continued and by the end of 1982, the unit still only boasted seven aircraft. Col James S. Allen had assumed command of the 4450th, from Col Bob Jackson on 17 May 1982 and by 28 October 1983, Senior Trend was deemed to have achieved Limited Initial Operational Capability (LIOC). As the potential of Senior Trend became increasingly more apparent to those cleared into the program, the procurement plan was increased to a total of 57 aircraft (the final total was 59). The impact of this decision creat­ed the need for two additional squadrons, consequently in July 1983, І-Unit “Nightstalkers”, was activated, to be followed in October 1985 by Z-Unit, “Grim Reapers” (later redesignated the 4450th Test Squadron and the 4453rd Test and Evaluation Squadron respectively).

In 1988, Hughes was granted a development contract to add a Moving Target Indicator (MTI) capability to ASARS. However, the actions of Saddam Hussein inter­rupted operational tests of the system, by the 17 RW.

After the Gulf War, tests were successfully completed in October 1991 and the ASARS MTI became operational four years later. Now the system is capable of locating moving targets in search or spot modes.

After much Air Force deliberation, it was decided to upgrade the U-2 fleet with the General Electric F’101- GE-F29 turbofan engine. Of similar thrust to the J75, the newer engine promised to be much cheaper to maintain and was significantly lighter, with a much improved fuel consumption rate, thus restoring valuable performance lost through the expansion of the sensor package. It was first flown by Ken Weir in 80-1090 on 23 May 1989 and on 28 October 1994, a delivery ceremony w’as held at Palmdale, when the first three conversions were handed back to the Air Force, the engine having been redesignat­ed in the meantime the FI 18.

Despite President Bush’s optimistic remarks about the establishment of a new world order, following the collapse of communism in the Soviet Union, continued political instability in various parts of the world has ensured that the capabilities of the U-2 reconnaissance system are as much in demand today as they were back in 1956.

Below In all, 25 TR-1 As. two TR-1 Bs and two ER-2s were built using ‘White World’ money, at the Lockheed Martin Skunk Works plant at Palmdale – in addition, seven U-2Rs and a dual­control U-2R (T) were built ‘in the black’. (Lockheed Martin)

Mindful of the subsonic vulnerability of the U-2 to developing Soviet SAM systems, the Agency’s Richard Bissell contacted Kelly Johnson in the Autumn of 1957, and asked if the Lockheed Skunk Works team would conduct an opera­tional analysis into the relationship of an aircraft’s interceplibility, as a function of its speed, altitude and radar cross section (RCS). As Kelly was already immersed in related studies, he agreed to accept the project; the results of w hich concluded that flight at supersonic speed and extreme altitude, coupled with the use of radar absorbent materials (RAM) and radar attenuating design, greatly reduced, but not negated, the chances of radar detection and a successful interception. Encouraged by these results, it was agreed that further exploratory work should be conducted. During the closing months of 1957, the Agency invited Lockheed Aircraft Corporation and

Above right With studies conducted by Pratt & Whitney and the Skunk Works at an advanced stage, Kelly Johnson proposed a liquid hydrogen propelled U-2 follow-on design to Lt Gen Donald Putt, during a Pentagon meeting in early January 1956. This Special Access Required programme, codenamed ‘Suntan’ developed the original CL-325 design into the CL-400. On paper, capable of Mach 2.5 at 100,000ft it was finally cancelled in February 1959, due primarily to lack of design stretch and logistical problems concerning the positioning of its highly volatile fuel. However the proposal led directly to a series of hydrocarbon designs that would take aerospace into a new era. (Lockheed Martin)

Opposite top A shot taken early in the A-12 test programme depicts a bare titanium aircraft landing at Area 51.

the Convair Division of General Dynamics to field to – t

them non-funded, non-contracted design submissions for m a reconnaissance gathering vehicle, which adhered to the SJ aforementioned performance criteria. Both companies accepted the challenge and were assured that funding would be forthcoming at the appropriate time. For the next twelve months, the Agency received designs that were both developed and refined, all at no expense!

It was however, readily apparent to Bissell that the cost of developing such an advanced aircraft would be both high-risk and extremely expensive; government funding would be a prerequisite and to obtain this, various high – ranking government officials would have to be cleared into the programme and given concis, authoritative presentations on advances as they occurred. He therefore assembled a highly talented panel of six specialists under the chair of Dr Edwin Land. Between 1957 and 1959 the panel met on some six occasions, usually in Land’s Cambridge, Massachusetts office. Kelly and General Dynamics’ Vincent Dolson were at times in attendance, as w’erc the Assistant Secretaries of the Air Force, Navy and

Above When deployed to Kadena under operation Blackshield, A-12s sported an overall black scheme, carrying no national insignia and bogus serials. (CIA)

Below Agency pilot Ken Collins ejected safely from ‘926 on 24 May 1963. He is seen here wearing a David Clark S-901 full pressure suit. (CIA)

other select technical advisors. Code-named project Gusto by the Agency, Lockheed’s first submission, Archangel, proposed a Mach 3 cruise aircraft with a range of 4,000 nautical miles at altitudes of between 90-95,000 ft. This, together with his Gusto Model G2A submission, was well received by the Programme Office, as Kelly noted later. Convair on the other hand prepared the Super Hustler; Mach-4 capable, ramjet-powered when launched from a B-58 and turbojet assisted for landing. As designs were refined and re-submitted, the Lockheed offerings became shortened to A, followed by an index number, these ran from A-З to A-12. The design and designations from Convair also evolved and on 20th August 1959, final submissions from both companies were made to a joint DoD/Air Force/CIA selection panel. Though strikingly

different, the proposed performance of each aircraft was on a par.

On 28 August 1959, Kelly was told by the director of the programme that Lockheed’s Skunk Works had w’on the competition to build the U-2 follow-on. The next day they were given the official go-ahead, with initial funding of S4.5 million approved to cover the period 1 September to 1 January 1960. Project Gusto was now at an end and a new code name. Oxcart, was assigned. On 3 September, the Agency authorised Lockheed to proceed with anti – radar studies, aerodynamic, structural tests and engineer­ing designs.

The small engineering team, under the supervision of Ed Martin, consisted of Dan Zuck in charge of cockpit design, Dave Robertson fuel system requirements, Henry Combs and Dick Bochme structures, Dick Fuller, Burt Mc. Master and Kelly’s protege Ben Rich.

The ambitious performance sought in the new aircraft can’t be overstated: the best front-line fighter aircraft of the day were the early century-series jets, like the F-100 Super Sabre and F-101 Voodoo. In a single bound, the A-12 would operate at sustained speeds and altitudes treble and double respectively, of such contemporary fighters’ limits. The technical challenge facing the Skunk Works team was vast and the contracted time scale in which to achieve it was incredibly tight. Kelly would later remark that virtually everything on the aircraft had to be invented from scratch. Operating above 80,000 feet the ambient air temperature was minus 56 degrees Centigrade and the atmospheric air pressure just 0.4 pounds per square inch. But cruising at a speed of a mile every two seconds, airframe temperatures would vary from 245 to 565 degrees Centigrade,

Sustained operation in such an extreme temperature environment, meant lavish use of advanced titanium alloys, which account for 85 per cent of the aircraft’s structural weight, the remaining 15 per cent was comprised of composite materials. The decision to use such materials was based upon titanium’s ability to with­stand high operating temperatures. It weighs half as much as stainless steel but has the same tensile strength; in addition, conventional construction was possible using fewer parts – high strength composites weren’t available in the early sixties. The particular titanium used w’as B – 120VCA, which can be hardened to strengths of up to 200 Ksi. Initially the ageing process required 70 hours to achieve maximum strength but, with careful processing techniques, this was reduced to 40 hours. A rigorous (and expensive) quality’ control programme was set up, wherein

Top left Aircraft ‘932 was lost during a functional check flight (FCF) just prior to being redeployed back to the United States on 5 June 1968; its pilot. Jack Weeks, was killed in the incident,

(CIA)

Top rightThe classified unit designation of the CIA. A-12 desert dwellers, was the I 129th Special Activities Squadron, The Road Runners’. (Paul Crickmore Collection)

Above When the A-12 programme was cancelled, the remaining aircraft were flown from Area 51 to Palmdale and placed in storage. (Lockheed Martin)

for every batch of ten or more parts processed, three samples were heat treated to the same level as those in the batch. One was then strength-tested to destruction, another tested for formabilitv and the third held in reserve should processing be required. With more than 13 million titanium parts manufactured, data is available on all but a few. Using this advanced material involved a steep learning curve and it wasn’t long before problems arose. Titanium is not compatible with chlorine, fluorine or cadmium. A line for example, drawn on sheet titanium with a Pentel pen, will eat a hole through it in about 12 hours – all Pentel pens were recalled from the shop floor. Early spot welded panels produced during the summer had a habit of failing, while those built in the winter last­ed indefinitely. Diligent detective work discovered that to

prevent the formation of algae in the summer, the Burbank water supply was heavily chlorinated. Subsequently, the Skunk Works washed all titanium parts in distilled water. As thermodynamic tests got underway bolt heads began dropping from installations; this, it was discovered, was caused by tiny cadmium deposits, left after cadium-plated spanners had been used to apply torque. As the bolts were heated in excess of 320 degrees Centigrade, their heads simply dropped off. Remedy: all cadium-plated tools were removed from tool boxes.

Another test undertaken studied thermal effects on large titanium wing panels. An element 4ft x 6ft (1.2 x 1.8m) was heated to the computed heat flux expected in flight and resulted in the sample warping into a totally unacceptable shape. This problem was resolved by manu­facturing chordwise corrugations into the outer skins. At the design heat rate, the corrugations merely deepened by a few thousandths of an inch and on cooling returned to the basic shape. Kelly recalled he was accused of “trying to make a 1932 Ford Trimotor go Mach 3”, but added that “the concept worked fine”. To prevent this titanium outer skin from tearing when secured to heavier sub­structures, the Skunk Works developed stand-off clips, this ensured structural continuity while creating a heat shield between adjacent components.

Chosen powerplant would be the Pratt & Whitney JT11D-20 engine (designated J58 by the US military). This high bypass ratio afterburning engine was the result of two earlier, ill-fated programmes: Project Suntan (see p34, caption) together with Pratt & Whitney’s JT9 single­spool high pressure ratio turbojet rated at 26,0001bs in afterburner and developed for a US Navy attack aircraft, which was also axed. Nevertheless, the engine had already completed 700 hours of full-scale engine testing and results were very encouraging. As testing continued however, it became apparent that due to the incredibly hostile thermal conditions of sustained Mach 3.2 flight, only the basic airflow size (400 lbs per second of airflow) and the compressor and turbine aerodynamics of the orig­inal Navy J58 P2 engine could be retained (even these were later modified). The stretched design criteria, associ­ated with high Mach number and its related large air-flow turn-down ratio, led to the development of a variable cycle, later known as a bleed-bypass engine; a

Above Pictured at Area 51 with another A-12 just visible behind the gantry. M-21 .Article 134, serial 60-6940, is seen with a D – 21 mounted on its dorsal pylon. (Lockheed Martin)

Above right To aid ‘Mother/Daughter’ separation, a cylinder of compressed air was carried in the pylon. (Lockheed Martin)

Be/owThis shot, believed to be that of the ill-fated М-21, serial 60-6941, shows the aircraft in a later overall black scheme.

(Lockheed Martin)

concept conceived by Pratt & Whitney’s Robert Abernathy. This eliminated many airflow problems through the engine, by bleeding air from the fourth stage of the nine-stage, single-spool axial-flow compres­sor. This excess air was passed through six low-compression-ratio bypass ducts and re-introduced into the turbine exhaust, near the front of the after­burner, at the same static pressure as the main flow.

This reduced exhaust gas temperature (EGT) and produced almost as much thrust per pound of air as the main flow, which had passed through the rear compressor, the burner section and the turbine.

Scheduling of the bypass bleed was achieved by the main fuel control as a function of compressor inlet temperature (CIT) and engine rpm. Bleed air injection occurred at a CIT of between 85 and 115 degrees Centigrade (approximately Mach 1.9). To further minimise stalling the front stages of the rotor blades at low engine speeds, moveable inlet guide vanes (IGVs) were incorporated to help guide airflow to the compressor. These changed from an axial, to a cambered position, in response to the main fuel control, which regulated most engine functions. In the ‘axial’ position, additional thrust was provided for take off and acceleration to intermediate supersonic speeds, the IGVs then moved to the ‘cambered’ position, when the CIT reached 85 to 115 degrees Centigrade. Should IGV ‘lock-in’ fail to occur upon reaching a CIT of 150 degrees Centigrade, the mission was aborted.

When operating at cruising speeds, the turbine inlet

temperature (TIT) reached over 1100 degrees Centigrade; this necessitated the development of a unique fuel, devel­oped jointly by Pratt & Whitney, Ashland Shell and Monsanto, known originally as PF-1 and latterly as JP-7. Having a much higher ignition temperature than JP-4, standard electrical ignition systems were useless. Instead a chemical ignition system (CIS), was developed, using a highly volatile pyrophoric fluid known as tri-ethyl borane (TEB). Extremely flash sensitive when oxidised, a small TEB tank was carried on the aircraft to allow engine afterburner start-up both on the ground and when aloft; the tank was pressurised using gaseous nitrogen, to ensure the system remained inert. Liquid nitrogen carried in
three Dewar flasks situated in the front nose gear well was also used to provide a positive ‘head’ of gaseous nitrogen in the fuel tanks. This prevented the depleted tanks from crushing as the aircraft descended into the denser atmosphere, to land or refuel. In addition, the inert gas reduced the risk of inadvertent vapour ignition.

Oxcart received a shot in the arm on 30 January 1960, when the Agency gave Lockheed ADP the go-ahead to manufacture and test a dozen A-12s, including one two – seat conversion trainer. With Lockheed’s’ chief test pilot, Louis W Schalk now on board, work on refining the aircraft’s design continued in parallel with additional construction work at Area 51. A new water well was drilled and new recreation facilities were provided for the construction workers, who were billeted in trailer houses. A new 8,500 ft runway was constructed and 18 miles of off-base highway were resurfaced to allow half a million gallons of PF-1 fuel to be trucked in every month. Three US Navy hangars together with Navy housing units were transported to the site in readiness for the arrival of the A-12 prototype, expected in May 1961. However, difficul­ties in procuring and working with titanium, together with problems experienced by Pratt & Whitney, soon began to compound and the anticipated first flight date slipped. Even when the completion date was put back to Christmas and the initial test flight postponed to late February 1962, the first J58s would still not be ready. Eventually Kelly decided that J75 engines would be used in the interim to propel the A-12 to a ‘half-way house’ of

50,0 ft and Mach 1.6, this action took at least some of the pressure off the test team.

The flight crew selection process evolved by the

Pentagon’s Special Activities Office representative (Col Houser Wilson) and the Agency’s USAF liaison officer (Brig Gen Jack Ledford, later succeeded by Brig Paul Bacalis), got under way in 1961. On completion of the final screening, the first pilots were William Skliar, Kenneth Collins, Walter Ray, Alonzo Walter, Mele Vojvodich, Jack Weeks, Jack Layton, Dennis Sullivan, David Young, Francis Murray and Russ Scott (only six of the above were destined to fiv operational missions).

These elite pilots then began taking trips to the David Clark Company in Worcester, Massachusetts, to be outfit­ted with their own personal S-901 full pressure suits –

Bbove WhenTagboard was cancelled, two B-52Hs of the 4200th Test Wing, at Beale AFB, continued working with the D-2ls, which required rocket boosters to propel them to their cruise speed and altitude. (Lockheed Martin)

Be/owThe North American F-108 Rapier was to have been an Improved Manned Interceptor (IMI) capable of Mach 3. It was cancelled due to escalating costs. (Rockwell International)

just like those worn by the Mercury and Gemini astro­nauts. In late 1961, Col Robert Holburv was appointed Base Commander of Area 51, his Director of Flight Operations would be Col Doug Nelson. In the spring of 1962 eight F-101 Voodoos, to be used as companion trainers and to pace-chase, two T-33s for pilot proficiency and a C-130, for cargo transportation, arrived at the remote base. A large ‘restricted airspace zone’ was enforced by the Federal Aviation Agency (FAA), to enhance security around ‘the Area’ and security notices were brought to the attention of North American Air Defence (NORAD) and FAA radar controllers, to ensure that fast-moving targets seen on their screens weren’t discussed. Planned air refuelling operations of Oxcart aircraft would be conducted bv the 903rd Air Refuelling Squadron, located at Beale AFB, and equipped with KC – 135Q_ tankers which possessed separate ‘clean’ tankage and plumbing to isolate the A-12s’ fuel from the tankers’ JP4, and special ARC-50 distance-ranging radios for use in precision, long distance, high-speed join ups.

With the first A-12 now at last ready for final assem­bly, the entire fuselage, minus wings, was created, covered with canvas and loaded on a special 8100,000 trailer. At 2.30am on 26 February 1962, the slow moving convoy left Burbank and arrived safely at Area 51 at 1.00pm, two days later. By 24 April, engine test runs together with low – and medium-speed taxi tests had been successfully completed. It was now time for Lou Schalk to take to the aircraft on a high-speed taxi run that would culminate in a momentary lift off and landing roll-out onto the dry salt lake-bed. For this first ‘hop’ the stabili­ty augmentation system (SAS) was left uncoupled; it would be properly tested in flight. As A-12 article number 121 accelerated down the runway, Lou recalled:- “I had a very light load of fuel so it sort of accelerated

really fast… I was probably three or four per cent behind the aft limit centre of gravity when I lifted off the airplane, so it was unstable… Immediately after lift-off, I really didn’t think I was going to be able to put the airplane back on the ground safely because of lateral, directional and longitudinal oscillations. The airplane was very difficult to handle but I finally caught up with everything that was happening, got control back enough to set it back down, and chop engine power. Touchdown was on the lake bed instead of the runway, creating a tremendous cloud of dust into which 1 disappeared entirely. The tower controllers were calling me to find

Below Developed for the F-108, the Hughes ASG-18 radar intercept system, together with its GAR-9 missile, remained under development and both were flight tested in this special­ly modified B-58, nicknamed ‘Snoopy Г, due to its extended nose profile. Note camera pods under outboard engines to record missile separations. (Paul Crickmore Collection)

Bottom Kelly, up at Area SI, stands next to the third and final YF-I2A interceptor, Article 1003, serial 60-6936. (Lockheed Martin)

out what was happening and I was answering, but the UHF antenna was located on the underside of the airplane (for best transmission in flight) and no one could hear me. Finally, when I slowed down and started my turn on the lake bed and re-emerged from the dust cloud, everyone breathed a sigh of relief.”

Two days later Lou took the Oxcart on a full flight. A faultless 07:05am take off was followed shortly thereafter by all the left wing fillets being shed. Constructed from RAM, luckily these elements were non-structural and Lou recovered the aircraft back to Area 51 without further incident.

On 30 April – nearly a year behind schedule – Lou took the A-12 on its ‘official’ first flight. With appropriate government representatives on hand the 59-minute flight took the aircraft to a top speed and altitude of 340kts and 30,000ft. On 4 May, the aircraft went supersonic for the first time, reaching Mach 1.1. Kelly began to feel confi­dent that the flight test programme w’ould now progress rapidly, even recovering some time lost during the protracted manufacturing process. Another Lockheed test pilot, Bill Park joined the Skunk Works team to share the burden with Lou. On 26 June, the second A-12 arrived at Area 51 and was immediately assigned to a three-month static RCS test programme. The third and fourth aircraft arrived during October and November, the latter was a two-seat A-12 trainer, nicknamed ‘the Goose’ by its crews. The aircraft was powered throughout its life by two J75s. On 5 October, another milestone was achieved when the A-12 flew for the first time with a J58, (a J75 was retained in the right nacelle until 15 January 1963, when the first fully J58-powered flight took place).

When Randy Anderson’s U-2 was shot down by an SA-2 over Cuba on 27 October 1962, the U-2’s vulnera­bility was once again demonstrated in spectacular fashion. The significance of the incident was certainly not lost on

Above YF-12 A prototype, Article 1001, serial 60-6934, makes a low, fast pass for the cameras. Note the extended ventral fin together with the fins under its engine nacelles to improve longitudinal stability, together with the under-side camera pods to record missile separation and the IR sensor in the forward chine below the cockpit. (Lockheed Martin)

Below Boeing JQB-47E-45BO, serial 53-4256, was one of a number of remotely piloted B-47 drones used to evaluate missile and radar performance. It was operated by the 3214th drone maintenance Squadron, at Eglin AFB, during the YF-12 trials off Florida. Note stencilling. (Paul Crickmore Collection)

Right When the YF-12 programme was cancelled Col J Sullivan and Col R Uppstrom ferried the aircraft to Wright-Patterson AFB where it is now on permanent display at the Air Force Museum as the sole surviving example. (Lockheed Martin)

intelligence communities involved in Oxcart and the successful prosecution of that programme now became a matter of highest national priority.

A third Lockheed test pilot, Jim Eastham, was recruit­ed into Oxcart, but still the programme was beset with problems, most of which were focused around the engines and Air Inlet Control System (AICS). The AICS regulat­ed massive internal air flow throughout the aircraft’s vast flight envelope, controlling and supplying air to the engines at the correct velocity and pressure. This was achieved using a combination of bypass doors and trans­lating centre-body spike position. At ground idle, taxying and take-off, the spikes were positioned in the full- forward position, allowing air to flow unimpeded to the engine’s compressor face. In addition, supplementary flow was provided through the spike exit-louvres and from six forward bypass exit-louvres. Early tests revealed that the engine required an even greater supply of air when oper­ating at low power settings. This deficiency was overcome by installing additional bypass doors just forward of the compressor face. The size of these variable-area ‘inlet ports’ was regulated by an external slotted-band and could draw air through two sets of doors. The task of opening or closing these doors was manually controlled by the pilot initially, but this was accomplished much later automatically, when a Digital Automatic Flight Inlet

Control System (DAFICS) computer was developed. – i

Together, the forward bypass doors and the centre-bodv m spikes were used to control the position of the normal £

shockwave just aft of the inlet throat. To avoid the loss of ^ inlet efficiency, caused by an improperly positioned shockwave, the wave was captured and held inside the converging-diverging nozzle slightly behind the narrowest part of the ‘throat’, allowing the maximum pressure rise across the normal shock. Once airborne with landing gear retracted, the forward bypass doors closed automatically.

At Mach 1.4 the doors began to modulate automatically to obtain a programmed pressure ratio between ‘dynamic’ pressure at the inlet cowl on one side of the ‘throat’ and ‘static’ duct pressure on the other side. At 30,000ft and Mach 1.6, the inlet spike unlocked and commenced its rearward translation, completing its full aft movement of 26 inches at designated speed Mach 3.2 (the inlet’s most efficient speed). Spike scheduling was determined as a function of Mach number, with a bias for abnormal angle of attack, angle of side slip, or rate of vertical accelera­tion. The rearward translation of the spike gradually repositioned the oblique shock wave, which extended back from the spike tip, and the normal shockwave, standing at right angles to the air flow, and increased the inlet contraction ratio (the ratio between the inlet area and the ‘throat’ area). At Mach 3.2, with the spike fully aft, the

‘capture-airstream-tube-area’ had increased 112 per cent (from 8.7sq ft to 18.5 sq ft), while the ‘throat’ restriction had decreased to 46 per cent of its former size (from 7.7 sq ft to 4.16 sq ft).

A peripheral ‘shock trap’ bleed slot (positioned around the inside surface of the duct, just forward of the ‘throat’ and set at precisely two boundary layer displacement thickness) ‘shaved’ off seven per cent of the inlet airflow and stabilised the terminal (normal) shock. This was then rammed across the bypass plenum, through 32 shock trap tubes, spaced at regular intervals around the circumfer­ence of the shock trap. As the compressed air travelled through the secondary passage, it firmly closed the suck – in doors while cooling the exterior of the engine casing before exhausting through the ejector nozzle. Boundary’ layer air was also removed from the surface of the centre – body spike at the point if its maximum diameter. This potentially turbulent air was then ducted through the spikes hollow supporting struts and dumped overboard, through nacelle exit louvres. The bypass system was thus able to match widely varying volumes of air entering the inlet system, with an equal volume of air leaving the ejector nozzle throughout the entire speed range of the aircraft.

The aft bypass doors were opened at mid Mach to minimise the aerodynamic drag which resulted from dump­ing air overboard through the forward bypass doors. The inlet system created internal pressures which reached 181bs per square inch when operating at Mach 3.2 and 80,000ft, where the ambient air pressure was only 0.4lbs per square inch. This extremely large pressure differential generated

Above Between 11 December 1969 and ЗI October 1979, NASA and the US Air Force embarked upon a joint high alti­tude test programme which required the use of two YF-12s and an SR-71. YF-12 60-6936 however was lost on 24 June 1971; both Lt Col ‘Jack’ Layton and Systems Operator Maj Bill Curtis ejected safely. SR-71 A, Article 2002, serial 64-17951 was redesignated YF-12C for political reasons and given the serial number 60-6937. (NASA)

Below The NASA flight test team were (left to right) Ray Young, Fitzhugh Fulton. Donald Mallick and Victor Horton. (NASA)

Right This Skunk Works document dated 6 April 1967, shows what the Air Force could have had – a Mach 3.2 reconnaissance aircraft, SR-71- a bomber, B-7I – and interceptor, F-12. (Paul Crickmone Collection) .

a pressure gradient, which in turn created a forward thrust vector, resulting in the forward inlet producing 54 per cent of the total thrust. A further 29 per cent was produced by the ejector, while the J58 engine contributed only 17 per cent of the total thrust at high Mach.

Inlet airflow disturbances resulted if the delicate balance of airflow conditions that maintained the shock­wave in its normal position were upset. Such disturbances were called ‘unstarts’. These disruptions occurred when the normally-placed supersonic shockwave was ‘belched’ forward from a balanced position in the inlet throat, caus­ing an instant drop in inlet pressure and thrust. With the engines mounted at mid-semi-span, the shockwave depar­ture manifested itself in a vicious yaw toward the ‘unstarted’ inlet. Sometimes these were so violent that crew members’ helmets would be knocked hard against the canopy framing. To break a sustained unstart and recapture the disturbed inlet shock wave, the pilot would have to open the bypass doors on the unstarted inlet and return them to the smooth-flowing, but less efficient posi­tion that they had occupied prior to the disturbance.

Early A-12 test flights involved increasing the aircraft’s speed by increments of one tenth of a Mach number and manually selecting the next spike position. If the inlet dynamics worked well, the aircraft was decelerated and recovered back to ‘the Area’; there the dynamics would be further analysed and incorporated. More often howev­er there would be a mismatch between spike position and inlet duct requirements and a vicious unstart would result. In all, it took 66 flights to push the speed enve­lope out from Mach 2.0 to Mach 3.2 and it wasn’t until pneumatic pressure gauges, installed on the inlet systems to sense pressure variations of as little as one-quarter of a pound per square inch, were replaced by an electrically controlled system from aircraft number nine (60-6932) onwards, that the incidence of unstarts plummetted.

Unlike their Senior Trend counterparts at Area 51, the operational pilots at TTR lived a bat-like existence, – sleeping during the day and fly ing only at night, it was both highly demanding and chronically tiring. At 01:13 hours on Friday 11 July 1986, in excellent weather and good visibility, Maj Ross E Mulhare departed Tonopah in aircraft ’792, callsign Ariel 31. 31 minutes later, ’792 ploughed into a hillside 2,280 ft above sea level, killing its

Above A-7s were used to provide pilots with a cover story for the 4450th’s actual mission. (USAF)

Below Pilots of the 37thTFW, 4I6TFS (Ghost Riders),attend a training briefing. (USAF)

Above Ordinance specialists load a 2,0001b GBU-10 practice bomb aboard a 37 TFW aircraft (USAF).

Right In April 1986, two RAF test pilots from Boscombe Down were invited to evaluate the F-l 17 at Tonopah, a fact. that remained shrouded in secrecy for over ten years. One of them, Sqd Ldr Dave Southwood. is seen pictured in an ETPS Jaguar.

(Crown Copy DERA, Boscombe Down)

pilot. The prime reason behind this horrific accident was almost certainly pilot fatigue and spatial disorientation.

The 4450th lost a second F-117A and pilot on 14 October 1987. Major Michael C Stewart got airborne front Tonopah at 19:53 hours, in aircraft ‘815, callsign BURNR 54. In common with the loss of ‘792, the accident report failed to clearly determine the cause, but yet again, repeated references were made to pilot fatigue and disorientation.

Six days after the tragic loss of Major Stewart, the 4450th became the centre of more unwanted attention, prompted by the loss of yet another of its aircraft. On this occasion Major Bruce L Teagarden (Bandit 222) safe­ly ejected from an A-7D after the aircraft lost power. Disastrously, the A-7 crashed into the Rantada Inn Hotel, near Indianapolis airport, killing nine people in the process, h’ollowing a detailed accident investigation however, Bruce was cleared of all culpability surrounding

Above On 10 November 1988, moves began to ease Senior Trend out of the Black, when Assistant Secretary of Defence J Daniel Howard first showed off this grainy picture at a Pentagon press conference. (USAF)

Below In September 1989, the 37th traded in its A-7s for more fuel efficient T-38s. (Lockheed Martin)

the tragic incident. Although publicly acknowledged as being a member of the 4450th, the unit was not known to have any links with Tonopah, ensuring that Senior Trend remained in the black.

During a Pentagon press conference on 10 November 1988, Assistant Secretary of Defense J. Daniel Howard, revealed to the world an extremely ‘grainy’ photograph of the F-117 and Senior Trend was slowly eased into the ‘white world’.

Gone was the need to shelter the 4450th’s covert activi­ty behind a valid aircraft type. Consequently in September 1989, the Wing said farewell to the trusty ‘SlufF and instead operated far more economical T-38A Talons, and later AT-38Bs, in the chase pilot proficiency role. Yet another change took place on 5 October 1989: the 4450th TG, together with its component squadrons, was redesignated. The parent designation was changed to the 37th Tactical Fighter Wing, the 4450th (Nightstalkers) together with the 4451st Test Squadron, became the 415th (Nightstalkers) and the 416th (Ghost Riders) respectively. The 4453rd Test and Evaluation Squadron (Grim

Above F-117A 802. first flew on 7 March 1984, it is pictured here over Lake Tahoe. (Lockheed Martin)

Reapers) continued in its responsibility as the Wings train­ing squadron, becoming instead the 417th Tactical Fighter Training Squadron (Bandits). The new designations had a proud historical provenance, being the first US night – fighter squadrons of the Second World War.

During December 1960, a separate project group working independently of the A-12 team, under Rus Daniell, was organised in the Skunk Works. From joint 715, (a point perpendicular to where the inboard wing leading edge meets the fuselage chine), the entire forward fuselage forebody of an A-12 was modified to create a Mach 3.2 interceptor. Originally designated AF-12, its 1,3801b Hughes AN/ASG-18 pulse Doppler radar and 818 lbs GAR-9 missile, had been intended for the North American F-108 Rapier, however following cancellation on 23 September 1959, DoD officials decided that devel­opment of this outstanding system should continue on a ‘stand alone’ basis. Therefore Hughes continued R&D

Above Bob Gilliland completes a fly by in ‘950 on its maiden flight over runway 25 at Palmdale. He is being chased by Jim Eastham in F-104 60790. (Lockheed Martin)

Below Lockheed test pilot Bill Weaver survived a Mach 3.1 break-up accident at an altitude of 81,000ft, in SR-7IA, 64­17952, on 25 January l966.Tragically, his flight test engineer, Jim Zwayer was killed. (Lockheed Martin)

Below right SR-7IA 64-17953 crashed on 18 December 1969 after an inflight explosion. Lt Col Joe Rogers and RSO Lt Col Garry Heidlebaugh ejected safely. (Lockheed Martin)

Below, right and below right Lt Col Bill Skliar (pictured) and his RSO, Maj Noel Warner, had a lucky escape at Edwards on I I April 1969, when a wheel disintegrated on rotation and set

80,0 lbs of JP-7 ablaze. Luckily both men managed to escape uninjured. SR-71 A, 64-17954 however, was written off. (Paul Crickmore Collection)

work with both systems utilising a specially modified Convair B-58A Hustler.

On 31 May 1960, the Air Force conducted a mock-up review of the AF-12 and were duly impressed. By June, AF-12 wind turned tests revealed directional stability problems resulting from the heavily revised nose profile and cockpit configuration. As a result a large folding fin was mounted under the aft fuselage, as were two shorter fixed fins beneath each nacelle. A bomber version of the A-12, designated the RB-12, also reached the mock-up stage, but this would prove to be still-born, as it repre-, sented too much of a threat to the highly political North American XB-70A Valkyrie. On 7 August 1963, several weeks after being moved to Area 51, Jim Eastham climbed aboard the interceptor prototype and took aircraft 60-6934

(the seventh A-12), for its first flight; a flight he would later modestly describe as a ‘typical production test flight’.

On 24 May 1963, the program received a temporary set back when Agency pilot Ken Collins was forced to eject from A-12 60-6926, during a subsonic test flight. The crash occurred 14 miles south of Wendover, Utah; a press cover story referred to the aircraft as being a Republic F – 105 Thunderchief, thus preserving security. An accident investigation established the cause of the incident to be a pilot-static system failure due to icing.

As 1963 drew to a close, nine A-12s at Groom Lake had notched up a total of 573 flights totalling 765 hours. A year later, eleven A-12s had logged over 1,214 flights amounting to 1,669 hours – only 6 hours 23 minutes however was at Mach 3 and only 33 minutes at design

speed, Mach 3.2. As Oxcart grew in size and cost, concern was expressed within both the Agency and Air Force as to how much longer the program could be kept a secret. It was also noted that technological data accumu­lated during the project would be of immense value in conjunction with ‘white world’ feasibility studies into supersonic passenger transport. In November 1963, President Johnson was briefed on the programme, after which he directed that a formal announcement be prepared for release early in the new year. Kelly Johnson noted in his diary “Plans going forward for surfacing of the AF-12 program. I worked on the draft to be used by President Johnson and proposed the terminology ‘А-1Г as it was the non-anti-radar version.” On Saturday 29 February 1964, a few’ hours prior to the President announcing the existence of part of the programme, two AF-12s, 60-6934 and 60-6935 were flown from Area 51 to Edwards AFB, by Lou Schalk and Bob Gilliland, thereby diverting attention away from Area 51 and the ‘black w’orld’ A-12 programme. At Edwards a ‘buzz’ had gone out to a few senior staff that something special might be happening on the first morning of their weekend off. In consequence, a few1 dozen people witnessed the arrival of the extremely sleek interceptor, the like of which no one outside the programme had seen – except for a few desert dwellers and the occasional incredulous sighting by airline crews. Lou Schalk recalls taxying to their assigned hangar as eyes bulged and heads nodded in utter disbelief. Unfortunately, the arrival lost a touch of elegance w hen, to aid push-back into the hangar, they turned the aircraft through 180 degrees. Lou recalls “ This turnaround sent hot engine exhaust gases flooding into the hangar which caused the overhead fire extinguishers valves to open. These valves were big – like the flood valves on hangar decks of aircraft carriers – and the desert hadn’t seen so much water since Noah’s embarkation!”

Above The rear fuselage section, aft of joint 715, is moved on to the next jig. (Lockheed Martin)

Below Temperatures excountered whilst at cruise speed and altitude dictated the use of titanium. (Lockheed Martin)

Now an Air Force program, the aircraft’s designation was changed to YF-12A to suit their system. The third YF-12A, 60-6936, soon joined the other two at Edwards and Jim Eastham continued the envelope expansion programme. On 16 April 1964, the first airborne AIM-47 missile separation test was conducted. Unfortunately, as onboard cameras showed, the weapon’s nose-down pitch was inadequate: had the rocket motor ignition also been fired, the missile would probably have ended up in the front cockpit! Back at ‘the Ranch’, on 9 July 1964, Bill Park experienced a complete lock-up of his flight controls in aircraft 60-6939 as he descended for landing following a high Mach flight. Despite trying to save the brand-new aircraft from rolling under while turning on to final approach, he couldn’t stop the bank angle from increasing and was forced to eject. Punching out at 200kts in a 34 degree bank, no more than 200 ft above the ground, Park was extremely lucky to survive unscathed.

A milestone in the programme was reached on 27 January 1965, when an A-12 flew’ a 2,580 mile sortie in one hour forty minutes, w’ith three-quarters of the flight time spent at Mach 3.1. On 18 March, YF-12A ‘935 successfully engaged a Qj2C target drone at 40,000ft, whilst the interceptor flew at Mach 2.2 and 65,000ft.

Then on 1 May 1965 (five years to the day that Gary Powers was shot down in his U-2), YF-12A 60-6936 siczed back from the Soviet Union six world speed and altitude records. Fourteen days later, the Skunk Works

Above To reduce the SR-71’s radar signature, radar absorbent material (RAM) is used. (Lockheed Martin)

Below An ingenious stand-off clip, developed by Skunk Works engineers, overcame the problem of attaching thin titanium sheets to bulkier structural components, without the former tearing due to expansion rates differentials. (Lockheed Martin)

Above The SR-71 is powered by two Pratt & Whitney JT11D-20 engines, designated J58 by the military. (Paul Crickmore)

below and bottom To regulate the amount of air required by the propulsion system throughout its vast operating envelope, the centrebody spike translates back and forth. (Paul Crikcmore)

received a contract for S500,000 for the production version of the interceptor, designated F-12B. However, production go-ahead was not given with the engineering contract. Nonetheless, considerable optimism was generat­ed. A further half-million dollars was granted on 10 November to keep basic F-12B design work alive. Similarly, Hughes received S4.S million to continue devel­opment of the AN/ASG-18 radar and fire control system.

On 29 March 1966, Kelly had a long meeting with Col Ben Beilis, System Project Officer (SPO) at Hughes Aircraft Company and various members of the F-12 test force, during which he was asked to take on the task of integrating the weapons systems; this he agreed to do and fire control tests were continued. However, Secretary of Defence McNamara opposed production of the aircraft.

As a result, on three occasions over the intervening two years, he denied the Air Force access to S90 million worth of funds which had been appropriated by Congress to begin F-12B production. Following a Senate Armed Sendees Committee hearing into the future of continental air defence, it was decided, in the light of intelligence

available at the time, to downgrade Aerospace Defence Command, which rendered the F-12B unnecessary. On 5 January 1968, official notification was received from the Air Force to ‘close down the F-12B’; the YF-12A programme was formally ended on I February 1968.

It would be the Blackworld, A-12 Oxcart program that validated the concept of sustained high Mach flight, but there was still a way to go…

The F-117A received its baptism of fire on the night of 19/20 December 1989, w hilst participating in a highly controversial action against General Noriega of Panama, codenamed Operation Just Cause. Panama had no defen­sive radar network. However, it was decided to commit these high value assets on the basis of their bombing accuracy. Consequently, eight F-l 17s from the 415th TFS took off from Tonopah. Two aircraft w ere airborne spares and returned to Tonopah follow ing completion of the

Below The USAF took delivery of its last F-1 17A, aircraft ‘843 on 12 July 1990. (Lockheed Martin)

initial AR, two aircraft in the lead cell, were targeted to attack an army base at Rio Hato, 65 miles southwest of Panama city. The four remaining aircraft were to take part in an operation which remains classified, but involved special forces attempting to capture Noriega.

This element of the mission was air aborted through lack of ground intelligence. The three thousand mile round trip required five AR’s, and was supported by KC-lOs from the 22nd Air Refuelling Wing, out of March AFB. This ever dependable unit, actually escorted the F-l 17As from Tonopah, all the way down to the Panamanian coast and back! The objective of Major Greg Feest, flying lead, in aircraft ’816, and his wingman Major Dale Hanner (Bandit 239) was to drop one weapon apiece, in an open field adjacent to barracks belonging to Battalion 2000, a unit known to be loyal to Noriega. Their purpose was to stun the sleeping soldiers and disorientate them before they had an opportunity to engage parachute landings by the 2nd and elements of the 3rd Ranger Battalion. However, three hours before the invasion was due to begin, the PDF were alerted to the impending attack and

deployed to one of the Ranger’s objectives – an air strip. As the two F-117As approached their target area, the wind changed direction, a target change was called, caus­ing confusion; the subsequent bombing results were at best questionable. The Chairman of the House Armed Services Committee, Les Aspin, later stated that target acquisition problems had also added to the pilots’ confu­sion because, “The humid, varied, vegetation… lowered the contrast and gave the [IRAD] system problems”.