In the initial stages of the N-156 project, Schmued favored a layout in which the engines were mounted on the wings, a location that he thought would make them easily accessible for maintenance. His chief engineer, Welko Gasich, disagreed: Wing-mounted engines produced excessive drag and aerodynamic disturbances. In Gasich’s opinion, the engines had to be within the fuselage. Schmued resisted for a long time but eventually capitulated, and a buried-engine mockup was built. Designer Lee Begin laid down the mold lines—the outer shape of the airplane. It was a thrilling shape, different from that of any other airplane of its era. The wings were vestigial, the vertical fin huge. The immensely long nose, exotically contoured and tapering practically to a point, seemed so far from the wing as almost to belong to another airplane. The swellings and hollows of its mid and aft fuselage—scooped out at the waist in accordance with aeronautical engineer Richard Whitcomb’s transonic area rule and expanding thereafter to envelop the engines—gave the fuselage a reclining-nude quality.
Northrop’s competitor for the supersonic trainer contract was the F-100F, a two-seat variant of North American’s F-100 Super Sabre. At the time, Northrop was not a supplier particularly in favor with the Air Force; North American was. Among Northrop’s pitches was one that is so obvious today that it is hard to believe that it was new to procurement offices in 1956. It was the idea of “life cycle costs,” which Gasich had brought with him from his previous employer, the RAND Corporation. While North American argued that the initial acquisition of the F-100F would be cheaper because the production line and the infrastructure for supporting the airframe and its engine were already in place, Northrop countered that in the long run, its new trainer would be cheaper because it used far less fuel and incurred lower maintenance costs. With two engines, it would also be safer; Northrop believed that it could bring the serious-mishap rate, then around 25 per 100,000 flight hours for the F-100, down to the range of seven to 10. The Air Force was persuaded. On June 15, 1956, a letter of intent was signed for what was now called the YT-38 Talon.
Several features changed during development. One was the arrangement of the vertical fin. A T-tail arrangement, like that of the F-104, with the stabilizer set atop the fin, had been considered and discarded early on, but the fin was originally designed with moderate sweep, like the wing. Flutter analysis indicated that the swept version might present difficulties. The crux of the matter was the stiffness of the aft fuselage, large portions of which had to be removable for engine access. In some jets, removing an engine required first removing the vertical fin, but it was a difficult design problem to make the fin easily detachable and yet sufficiently strong and stiff. Engineer Julius Villepique proposed what proved to be a key innovation. He fixed the fin to the keel structure that ran between the engines, and made the horizontal stabilizer, rather than the fin, the removable component, along with the “boat tail”—the entire aft shell of the fuselage surrounding the engines. The process of getting at the engines was extremely simple. Apart from the fasteners holding the fuselage shell together, the only parts that had to be disconnected were two push rods that connected the pilot’s control stick to the valve controlling the horizontal stabilizer’s hydraulic actuators. Hydraulic lines—there were only two—mated automatically, with internal check valves preventing loss of fluid.
The engines hung from rails on either side of the central keel. To avoid having to break and reconnect multiple hydraulic lines, designers mounted the hydraulic pump and other accessory drives on the fuselage, joined to the engine by a short driveshaft. Thanks to the rail support and the fuselage-mounted gearbox, once the boat tail had been detached, an engine could be removed and replaced in an hour.
Weight control was always a key factor in the trainer’s design. The N-156 was intended to weigh 10,900 pounds full up—a fantastically low figure when you consider that the fighters of the time generally weighed between 30,000 and 45,000 pounds. Eventually it would grow by about a ton—but even then it was a model of weight control. Its systems were simple. The hydraulically powered flight controls lacked manual reversion, and if both engines failed, the pilots’ only recourse was to eject. There was no fuel in the wings, no provision for external stores, and only basic systems for navigation and communication. Test pilot Lew Nelson took the prototype on its uneventful first flight on April 10, 1959.
“Science is done by single individuals, but engineering is done by a team, and I had a great team,” recalls Welko Gasich today. In his voice you can hear his affection for the airplane and its creators, and for a halcyon period—“the height of the great 1950s and ’60s screwdriver technology,” one pilot called it—during which every choice his team made turned out to be the right one.
Despite its radical appearance, the T-38 is a gentle airplane in the air, straightforward in character, almost viceless, and thoroughly conventional in handling. An unmistakable buffet gives ample notice of an impending stall. For a long time the aircraft refused to spin at all. The Air Force’s training command initially complained that the T-38 was too easy to fly, compared with the fighters for which it was supposed to be preparing new pilots. Gasich retorted that the Air Force ought to demand fighters that flew better—and that’s what eventually happened. Today’s fighters are so docile and forgiving that the T-38 is now, according to former instructor pilot Lewis Shaw, “the hardest airplane to fly in the Air Force’s fleet.”
It trains not only Air Force cadets, but test pilots as well. Says Northrop test pilot Roy Martin, “It replicates theory great; that’s what makes it such a marvelous teaching tool.” It flies just as textbooks say airplanes should. Lockheed Martin test pilot Dan Canin agrees with Martin up to a point, but adds that as far as test pilot training goes, the T-38’s main defect is that it’s too good an airplane—it doesn’t give students enough faults to identify. Canin’s favorite test pilot trainer was the de Havilland Beaver—“It had so many things wrong with it.”
Since Lee Begin first shaped it, the T-38 has continually inspired affection. Lewis Shaw still calls it “the 36-24-36 blonde on the beach.” Dan Canin raves: “I absolutely love the airplane. The T-38 and its siblings [F-5/F-20] are absolutely beautiful things…iconic, really…designed, it always seems to me, exactly as one would sculpt a fighter if he didn’t have to worry about anything practical…like fuel, weapon systems, etc. As we go exclusively with stealth designs, which are inherently fat to incorporate weapons internally, I doubt we’ll ever see fighters this good-looking again.”
Like all objects of infatuation, however, the T-38 has become encrusted with legend and exaggeration. It’s commonly said to roll at 720 degrees a second; the truth is 280 to 300, and in any case research suggests that anything above 220 merely serves to disorient the pilot. Another oft-repeated claim is that the T-38 climbs 33,000 feet a minute, even though the aircraft’s time-to-climb record, set by Walt Daniel in 1962, is three minutes to 30,000 feet. According to Northrop’s Roy Martin, a normal climb at military power—that is, maximum power without afterburner—is around 6,000 feet per minute.