Last week my two boys, Dylan and Andrew, and I went up to the Evergreen Museum in McMinnville, Oregon. We had not been there since the boys were ages four and seven (Dylan is entering Gutenberg College this year). In the last decade, Evergreen has become the one of the best aircraft and aerospace museums in the country. Its major attraction is the Spruce Goose, a “flying boat” and probably the most memorable aircraft other than the Wright Brothers’ Flyer to fly less than a mile total. In addition to its impressive World War II aircraft collection, the museum also houses rockets, capsules, and the SR-71 recon plane. When I was in the Air Force in the early 1970s, I worked with the SR-71 as part of my job with the National Security Agency (NSA). It was interesting to see the plane again and to show the boys some of its capabilities. In this post, I will focus on the Spruce Goose and the SR-71.
The Spruce Goose was designed and built by Hughes Aircraft (Howard Hughes) during World War II to fly troops and supplies non-stop from the east coast of the U.S. to Europe. Its mission was to help relieve the pressure on the merchant marine fleet which was being savagely attacked by German U-boats. From a design perspective, the plane was required to be built out of non-critical war materials. Probably the greatest irony about the plane is that it does not have one piece of spruce in it. Aircraft spruce was one of the most limited of war materials. (When the war ended, only a narrow, ten-mile strip of Sitka spruce located between Yachats and Florence, Oregon, had not been harvested in the continental U.S. The majority of aircraft spruce left at the end of WW II was in British Columbia and Alaska.) The Spruce Goose is mostly built out of laminated birch.
The Spruce Goose is the largest flying boat ever built. It is also among the last flying boats built. In other words, it was a dinosaur by the time it first flew. The 1930s and 1940s were the heyday of the flying boats. The most nostalgic of the flying boats were the Great Clippers. They established commercial flight routes across the Pacific to Manila. It took five days to island hop from San Francisco to Manila in the Philippines. They represented a viable technology until long runways were built on Pacific Islands and aircraft increased their range and level of reliability. The flying boats exchanged clean aerodynamics for the ability to take off and land on water. Once the runways were built and the technology became more reliable the flying boats became obsolete. A similar fate was faced by float planes, flying boats’ little brothers. Float planes are now dominant only in Alaska where land airports do not exist in sufficient numbers to provide an adequate transportation network.
The creation and demise of the flying boats is a clear example of the drive for economic and technical efficiency and its effects. The flying boats were only a viable solution to transportation problems for a short period of time. Then aviation went on without them. They were no longer economically viable. Land based planes could fly more people and goods cheaper and faster. All the people that flew and maintained the flying boats had to find new employment.
Shifting gears, the SR-71 is arguably the most technologically sophisticated aircraft ever built. It still holds most of the speed and altitude records for an airplane. Flying at more than Mach 3.2; it flies faster than a bullet fired from a rifle.
The SR-71 was designed to replace the U-2 as the U.S.’s high-altitude reconnaissance aircraft. The U-2 (called the Dragon Lady by pilots because it was a very difficult plane to fly and land) was designed for the CIA in the 1950s. Its mission was to overfly the U.S.S.R. during the Cold War. The U-2 was basically a jet powered glider that flew at extreme altitudes (above 75,000 feet). It was designed to fly higher than conventional fighter planes could go. Unfortunately, it was slow (around 500 mph). In 1960, the U.S.S.R. shot down a U-2 with a surface-to-air missile (SAM). This led to designing a new recon aircraft to overfly the U.S.S.R. The SR-71 could fly at least as high as a U-2, and in the event that a surface-to-air missile was shot at it, the SR-71 would simply outrun the missile.
A number of very sophisticated technological developments were necessary to allow the plane to fulfill its mission. The aircraft was largely built out of titanium. Most aircraft only have titanium on surfaces that experience high temperatures. The SR-71 was constructed of about 85% titanium. The aircraft was built loose and only became tight during flight when the surface temperatures increased. Considerable amounts of fuel would leak from the plane on the ground. It would take off, fly initially at high speed to heat and expand the surfaces, and then refuel aerially for its mission. In flight, it also cycled fuel to the wings to cool the leading edges. Needless to say, the fuel was not normal aircraft fuel.
A total of thirty-two aircraft were built. During its thirty-four years of active duty, twelve were destroyed. None were shot down. Only one crew member died. The rest all ejected safely. In addition to photo and remote sensing capabilities, signal intelligence (radio signals) could be gathered as could electronic warfare information.
The cameras on board were incredible. As the exhibit showed, the cameras photographed the ground from over 75,000 feet. Yet it is easy to identify the make and model of cars and trucks in the photographs. The SR-71 could fly its photo mission at greater than Mach 2. So for example, the SR-71 could overfly all of Vietnam (a narrow country) in less than an hour, and the photos allowed one to identify the make and model of cars anywhere in the country.
One would think that that such an aircraft would still be actively flown today, but that is not the case. All the SR-71s were retired in 1998. In another aviation irony, the only remaining dedicated high-altitude reconnaissance plane in the U.S. Air Force inventory is the U-2, the SR-71’s predecessor.
What did in the SR-71? Its mission is still viable. Satellites are not as mobile as an aircraft; it takes awhile to move a satellite over a target area. The SR-71 can provide photo intelligence on short notice anywhere in the world, and there is virtually no way to shoot it down. The SR-71’s mission didn’t go away, nor has a better aircraft been designed to replace it (some people say there is an active replacement, the Aurora, but it is classified); the U.S. Congress just decided it was too expensive to fly and maintain the nine aircraft then operational. What doomed the plane was partly the secret nature of its capacities: it had few knowledgeable advocates. Too few people making decisions truly understood the nature and demands of gaining intelligence information and the role the aircraft could play, and its few advocates did not want to make all its secret capabilities known, so they did not strongly defend the aircraft program. Also, the plane was part of the Air Force’s mission. Most line officers in the Air Force have no use for intelligence. The glamorous missions are fighter planes and bombers; an assignment to an intelligence organization is largely a death warrant for an Air Force career. So when push came to shove over budget issues, the SR-71 was doomed.
The boys and I enjoyed the time we spent at the museum. For anyone interested in aviation or space exploration, the museum is a must. At the end of the day, I did find myself reflecting on one question, though: Did Howard Hughes take off in the Spruce Goose during a taxi test on purpose or by accident? He always claimed the plane just took off by itself. His opponents had largely killed the Spruce Goose program because they were convinced that the plane could never fly. As I pilot, I have to smirk. Howard Hughes was an exceptional pilot, and to have the largest flying boat in the world accidentally take off for the first time under total control and fly at about fifty feet elevation for a mile (a difficult maneuver) and then make a perfect landing is a fine piece of work. It proved one thing for sure: the Spruce Goose was at least airworthy. It was truly the world’s largest flying boat.