Ironically, airframe icing was not judged to be a problem; chief aerodynamicist Dick Cantrell said that any ice buildup would only help the plane's aerodynamics.[418]
If the Senior Trend was to be an effective bombing platform, the avionics systems would have to show capabilities never before achieved. The pilot would have to find the target, which was not an area or a wide-spread factory but rather a specific part of one specific building, then direct the LGB to the aim point — all in the dark.
The heart of the Senior Trend's bombing system was a pair of infrared turrets — the forward-looking infrared (FLIR), located in the front of the plane, and the downward-looking infrared (DLIR) on the plane's underside.
Each turret was mounted in a well that was covered by a fine-mesh, radar-absorbing screen. The two-turret design was able to scan from just above the horizon to below and behind the aircraft. The image from the system was displayed on the instrument panel's central cathode-ray tube.
The design posed many problems. To give one example, the FLIR turret would have to pick up the target at long range, then track it as the plane approached. The FLIR would then have to "hand off" the target to the DLIR without losing the target lock. To create this seamless display, the two turrets had to be exactly aligned (called boresighting).
Flight testing of the system revealed numerous problems. It proved impossible to electronically boresight the two turrets, which created problems in the handoff. Problems with the video display included "windshield wiper noise," "jello," "shimmering," "picket fence noise," and "horizon shadow-ing." Added difficulties included problems with level and gain controls, turret slew rates, and target acquisition and illumination.
Some of the problems were purely subjective, which made it even more difficult. There were three test aircraft (FSD 3, 4, and 5) and six test pilots; what one pilot judged unacceptable on one plane was called good by another pilot. A "Tiger Team" was organized to sort out the systems problems.
It was headed by the Skunk Works chief scientist and drew man power from other Lockheed divisions.
Like the engineers who had worked on earlier Black airplanes, the team came up with innovative, simple solutions to the complex problems. They abandoned efforts to electronically boresight the turrets and used a mechanical procedure. The aircraft was rolled up a thirty-inch-high ramp.
This raised the nose and allowed both turrets to view the same target board simultaneously. They could then be aligned. To prevent the control surfaces from scraping the ground, mattresses were placed under them when the hydraulic system was shut down. A portable boresight fixture was developed, the turret mounts were fixed in place with epoxy, and tolerances were tightened. Reliable handoffs could then be accomplished even in "dive-toss" drops: this involved the plane going from level flight into a dive, then pulling up and releasing the bomb. Three FLIR-DLIR handoffs were required for this maneuver. Another difficult flight maneuver was loft bombing, where the plane goes from level flight into a steep 4-g pull up. The bomb is released during the pull up and is "thrown" toward the target. The video display problems were traced to electromagnetic interference due to poor shielding. The target lock-on problems were corrected with new software.
For flight testing of the modifications, the team developed what was described as "a broadband, wide-spectrum, inexpensive, expendable, point-source IR target." This was a barrel filled with glowing coals — a backyard barbecue.
In all, it took a year and some 100 test flights to correct all the problems.
When the work was completed, one aircraft dropped a 2,000-pound, inert GBU-27 laser-guided bomb, which scored a direct hit on the barrel.[419]
Major Alton C. "Al" Whitley had flown two tours in Vietnam, one in F-lOOs and the other as a search and rescue A-7 pilot, but this was a new and novel experience. He had been called to a small interview room at Nellis Air Force Base. When he knocked on the door, a man opened it an inch and asked if he was Whitley. He said yes, and the man asked for his ID card. The man took it and closed the door. A minute later, he reopened it and said, "Yeah, you're Whitley."
Once Whitley was in the room, he was offered a chance to fly with a top-secret unit. The duty would require constant separation from his family, and he could not be told much more. He had five minutes to decide, and when he left the room, the decision stood. Whitley did not know what airplane he would be flying, or what the unit would be doing. He responded, "Sign me up. I'll do it."
Whitley thus became a member of a secret brotherhood composed initially of about ten officers and a dozen enlisted men — the 4450th Tactical Group.
The unit commander was Col. Robert A. Jackson. He was to select and train the initial group of pilots. He was looking for pilots who were both experienced and mature — majors and senior captains with a thousand hours of flight time and air-to-air and/or air-to-ground backgrounds (F-4s, F-15s, F-llls, A-7s, and A-lOs). Colonel Jackson met with each candidate. Once they agreed, the pilots were told to go back to their units and wait for a call.
Although the 4450th Tactical Group was formally established on October 15, 1979, training did not begin until June 1981. Whitley and the other pilots spent time at Lockheed in the cockpit procedures trainer. This was a model of the cockpit on which the pilot could learn the layout of the various consoles, but not how the plane would fly. On seeing the FSD aircraft under construction, the pilots' initial reactions were to wonder if that strange-looking airplane could really fly.
Ironically, the unit that was to fly the world's first stealth aircraft had no airplanes. All the FSD aircraft were used for testing. Soon after the unit began training, they received A-7s. These were organized into the P-Unit (later called the 4451st Test Squadron). The A-7s were to provide both pilot-proficiency training and cover. The 4450th Tactical Group's cover story was that it was an A-7 avionics and evaluation unit.[420]
At the same time, the base the unit was to use was under construction — the Tonopah Test Range (TTR). It had originally been built to support drop tests of nuclear weapons. The TTR was on the north side of the Nellis range, 140 miles from Las Vegas and northwest of Groom Lake. The nearest town was Tonopah, Nevada. The area was open range, with wild horses running free.
The base was immediately staffed with air force security police. The flight line was walled off with a double fence; the only access to the runway was through gates. The area between the fences was lighted at night and had intruder detectors. At first, the facilities were limited to a few buildings, a small mess hall, and sixteen winterized trailers. These were soon replaced by dormitories and hotel-style rooms for the pilots and support personnel.
Because all the flights were done at night, the rooms featured blackout cur-tains to keep out the sun during the daylight sleeping hours. The runway, taxiways, and aprons were all improved, while maintenance facilities, fuel and water tanks, fire stations, and a dining hall were built. Individual hangars were also constructed for each aircraft. In addition to providing protection from the weather, these hangars also hid the planes from prying eyes during the day.[421]
Before the 4450th Tactical Group could become a fully functional unit, it would need the production Senior Trend aircraft. It was the spring of 1982 before the first aircraft, 785, was ready. Its first flight would end in a near fatal crash.
420
Macy,