We also learned the hard way that titanium was totally incompatible with many other elements, including chlorine, fluorine, and cadmium. When one of our engineers drew a line on a sheet of titanium with a Pentel pen, he discovered that the chlorine-based ink etched through the titanium just like acid. Our mechanics working on the engine installation used cadmium-plated wrenches to tighten bolt heads. When the bolts became hot, the bolt heads just dropped off! It took intensive detective work to zero in on the cadmium contamination culprit, and we quickly removed all cadmium-plated tools from toolboxes. Even the routine matter of drilling a hole became a nagging frustration. When machining standard aluminum, a hundred holes could be drilled without resharpening the bit. With titanium, we had to resharpen every few minutes and were forced to develop special drills using special cutting angles and special lubricants, until we finally were able to drill more than 120 holes before having to resharpen. But it took us months of painstaking experimentation to get that far.
Miles of extrusions were required to produce an aircraft the size of the Blackbird, so it was necessary to invest time and more than a million dollars in new state-of-the-art precision drills, cutting machinery, powerheads, and lubricants.
For each problem solved, two or three others suddenly cropped up. We were stunned when spot welds on panels began to fail within six or seven weeks. Some intensive sleuthing revealed that the panels had been welded during July and August, when the Burbank water system was heavily chlorinated to prevent algae growth. The panels had to be washed after acid treatment, so we immediately began using only distilled water. During heat tests, the wing panels warped so badly they looked like potato chips. We worked for months to find a solution and finally used corrugated panels that allowed the metal to expand without warping under immense heat friction. At one point an exasperated Kelly Johnson told me: “This goddam titanium is causing premature aging. I’m not talking about on parts. I’m talking about on
We set up training classes for machinists using titanium for the first time and a research operation for developing special tools that would make their jobs easier. Between the new machines and the training, our bean counters figured that ultimately we saved $19 million on the production program.
Still, unforeseen problems kept increasing the costs, and only a few days after the November 1960 elections, which brought John F. Kennedy into office and took the Republicans out, Kelly returned from a week’s vacation and found a wire awaiting him from Dick Bissell, inquiring about what it would cost the government to cancel the Blackbird program. “I am very afraid,” Kelly noted in his private log, “about what will be Kennedy’s attitude toward the program, its overall cost increase, which is very high on all fronts, and the fact that our Russian friends have now come up with a new Tall King radar which appears to be capable of detecting a target about one-third the size that we are able to accomplish with the Blackbird. With all this we have made remarkable strides in reducing the radar cross section, and our experts say we would have about one chance in 100 of being detected, with practically no chance of being tracked.”
Our chief chemist, Mel George, helped us to develop special antiradar coatings loaded with iron ferrites and laced with asbestos (long before it became a dirty word) to be able to withstand the searing heat from the tremendous friction hitting the leading edges of the airplane. These coatings were effective in lowering the radar cross section and comprised about 18 percent of the airplane’s materials. In effect, the Blackbird became the first stealth airplane; its radar cross section was significantly lower than the numbers the B-1B bomber was able to achieve more than twenty-five years later.