Skunk Works

Of course, Henry was no happier with the prospect of building a steel airplane than I was. More weight meant more internal support structure, more fuel, less range, and less altitude. Back in 1951 he had recommended to Kelly that we use a rare alloy called titanium for the white-hot exhaust nozzles on the afterburner of the supersonic F-104 Starfighter. So Henry Combs now was mulling the pluses and minuses of building the world’s first titanium airplane. It would be a huge risk. On the positive side, titanium was as strong as stainless steel but only half its weight and could withstand blast-furnace heat and tremendous pressures. Titanium’s tensile strength would allow us to make our wings and fuselage paper-thin. But to build a high-performance aircraft out of such an unproven exotic material was inviting potential disaster. “Unpredictability is a guarantee that we’ll be in the soup on this one from start to finish,” Henry predicted dourly. I knew he was right. Meanwhile, Kelly was already pondering the titanium idea himself. “Any material that can cut our gross weight nearly in half is damned tempting,” Kelly told Combs, “even if it will drive us nuts in the bargain.”

Only one small U.S. company milled titanium, but sold it in sheets of wildly varying quality. We had no idea how to extrude it, push it through into various shapes, or weld or rivet or drill it. Drilling bits used for aluminum simply broke into pieces trying to pierce titanium’s unyielding hide. This exotic alloy would undoubtedly break our tools as well as our spirits. At one of our daily seven a.m. planning sessions in Kelly’s office, I volunteered some unsolicited advice about how we could use a softer titanium that began to lose its strength at 550 degrees. My idea was to paint the airplane black. From my college days I remembered that a good heat absorber was also a good heat emitter and would actually radiate away more heat than it would absorb through friction. I calculated that black paint would lower the wing temperatures 35 degrees by radiation. But Kelly snorted impatiently and shook his head. “Goddam it, Rich, you’re asking me to add weight—at least a hundred pounds of black paint—when I’m desperately struggling to lose even an extra ounce. The weight of your black paint will cost me about eighty pounds of fuel.” I said, “But, Kelly, think of how much easier it will be to build the airplane using a softer titanium, which we can do if we lower the heat friction temperatures on the surface. Adding a hundred pounds is nothing compared to that.”

“Well, I’m not betting this airplane on any damned textbook theories you’ve dredged up. Unless I got bad wax buildup, I’m only hearing you suggest a way to add weight.”

Overnight, however, he apparently had second thoughts, or did some textbook reading on his own, and at the next meeting he turned to me as the first order of business. “On the black paint,” he said, “you were right about the advantages and I was wrong.” He handed me a quarter. It was a rare win. So Kelly approved my idea of painting the airplane black, and by the time our first prototype rolled out the airplane became known as the Blackbird.

Our supplier, Titanium Metals Corporation, had only limited reserves of the precious alloy, so the CIA conducted a worldwide search and, using third parties and dummy companies, managed to unobtrusively purchase the base metal from one of the world’s leading exporters—the Soviet Union. The Russians never had an inkling of how they were actually contributing to the creation of the airplane being rushed into construction to spy on their homeland.

Even before the first titanium shipment arrived, many of us were already worrying that building this particular airplane might just prove too difficult, even for the Skunk Works. Wind tunnel tests of our mock-up amazed us all by indicating that, at Mach 3, intense friction heating on the fuselage would actually stretch the entire airframe a couple of inches! The structures people struggled like medieval alchemists to find rare and exotic metals that could withstand such blowtorch temperatures. They recommended that the hydraulic lines be of stainless steel; for the ejector flaps they found a special alloy called Hastelloy X; and they recommended making our control cables out of Elgiloy, the material used in watch springs. Plumbing lines would be gold-plated since gold retains its conductivity at high temperatures better than silver or copper. Kelly just fumed watching our materials costs rocket into the stratosphere.