by Larry Grooms, special to Aerotech News
An online seminar on aerospace history in the region where the history was made, explained how two decades passed between the time researchers found a way to dial-down volume of sonic booms and the federal government funded a project intended to move the demonstrated theory into practice.
The preview glimpse into a fast-approaching future came about when local units of two professional associations, the American Institute of Aeronautics and the Society for the Advancement of Material and Process Engineering invited retired test pilot Marvin L. “Roy” Martin to recall a research project that began 20 years ago, was found to be valid in 2003, and although declared to be politically D.O.A. in 2005, was politically resurrected in 2016.
Martin remembers that when Northrop Grumman submitted the design proposal to NASA in 2005, NASA said unless the project was about going to the Moon or Mars it wouldn’t be approved. When the design proposal was reinstated in 2016, Lockheed won with the X-59 QueSST for NASA. By that time, Northrop Grumman was loaded up with work on the B-2, Global Hawk and other projects.
The tale of two airplanes, as shared by Martin, begins with a Defense Advanced Research Projects Agency offer of $4.5 million to any aerospace company willing to gamble on creating a proof of concept design capable of making sonic booms less offensive. Northrop Grumman engineers and scientists had a theory that changing the aircraft fuselage shape would minimize soundwaves created when a plane transitions to supersonic speed.
What was titled the F-5 Shaped Sonic Boom Demo was considered a non-profitable but low risk, cost-effective and affordable project with a possibility for future business if successful.
Overland supersonic flight, except in designated areas for military and research operations, has been illegal for years in the U.S. and most other nations. Russian TU-144 and the British-French Concorde airliners were restricted to supersonic speeds only over water.
Since restrictions were driven by public complaints about sonic booms, it was thought that reducing the shock to tolerable levels would create greater business opportunities. Aerospace contractors volunteered to help Northrop Grumman, Martin said. Lockheed Martin, for instance, provided wind tunnel testing, and the Navy provided an aging F-5E bound for the Boneyard. Boeing loaned the project a chase plane. NASA oversaw the data handling for DARPA. The modified F-5 was flight-tested over the Atlantic just offshore in Florida, where its new composite nose section was created.
Back at Edwards, the day of reckoning arrived on Aug. 27, 2003. Moving at a precise speed and altitude required to produce a sonic boom at exactly the correct point, the aircraft overflew a lengthy array of microphones positioned on the desert floor. The data was solid. The reconfigured F-5 reduced the sonic boom noise by one-third.
“Everybody was stoked,” Martin said. “We had engineers dancing in the desert.”
On a personal note, test pilot Martin, who logged 10,800 hours in more than 70 aircraft types, mentioned that he flew all 21 test flights in the sonic boom project. “For a test pilot, it just doesn’t get any better than that.”
Historian remembers flight test lore
John T. Murphy, director of history for the Air Force Test Center at Edwards, traced the family tree of pioneers in flight research, beginning with the Wright Brothers and their contemporaries, and following the trail of leadership into current times.
Recapping the story of how Edwards AFB came into being, Murphy went as far back as what he called “the golden age of flying” in the years after the end of the First World War. In 1920, McCook Field, a small airport near Dayton, Ohio, was a location for testing Army aircraft until combined with the larger and adjacent Wright Field, named to honor the two bicycle builder brothers from Dayton who went down to Kitty Hawk, N.C., to learn how to fly an airplane they built from scratch. They were, Murphy said, the original test pilots.
With the growth of the aviation industry in California in the period just before the U.S. entered World War II, the Army Air Corps selected Muroc Airfield to centralize and standardize the foundational process of flight testing created by the bicycle builders from Dayton.
Along with the legendary test pilots, scientists, and senior commanders whose names became household words over the years, Murphy recalled others whose missions were equally critical. One of those was Col. John Stapp, a medical doctor and scientific researcher into the effects of rapid acceleration and G-forces on human beings. When Chuck Yeager flew faster than the speed of sound in 1947, the doctor’s examination room became the Rocket Sled Test Track on the South Base at Edwards. Not content with just examining and caring for the rocket-propelled sled riders, Stapp strapped himself in on multiple occasions, surviving 38-Gs, also expressed as 38 times the force of gravity.
Perhaps not as widely remembered as acclaimed test pilots Pete Knight, Neil Armstrong and Scott Crossfield was Al Boyd, a man characterized by Murphy as “The father of American Test Pilots.” According to Murphy’s records, Boyd had the distinction of being the only test pilot to fly in his career 700 aircraft types, including every aircraft type in the Air Force inventory. And Murphy explained it was a Lt. Gustav Lundquist who oversaw the opening of an institution that sealed the deal for aeronautical research at Edwards — the Air Force Test Pilot School.
Flying wings in space
For a contemporary historical retrospective on one of the longest running, most glamorous and widely publicized aerospace research programs, the Antelope Valley Chapter of AIAA called on Michelle Evans, who wrote the book on it: The X-15 Rocket Plane — Flying the First Wings Into Space.
Faced with a program measured in minutes, Evans adroitly offered a behind the scenes montage of rarely seen X-15 photos, graphics, drawings and test pilot portraits. And she narrated the show with a rapid-fire monologue blending humor, suspense, humanity, triumph, heartbreak, and disaster. She launched her show with a photo of a test pilot wearing a new MC-2 pressure suit. The garment, she pointed out, was designed and assembled by a girdle manufacturer, thereby becoming “the foundation of American aerospace.”
Delving into the bureaucratic side of the X-15 program, Evans reported how Forrest Peterson, the Navy’s only active-duty X-15 test pilot, was able to meet his “sea duty requirement” for promotion in rank without leaving the X-15 slot. The brass cut new orders, officially transferring Peterson’s duty station to the Naval Air Station on “China Lake.” A little dry humor?
Evans may also have cleared up the question of how the X-15 test program lasted from 1961 to 1968 when the limited number of airframes seemed to so frequently suffer crash landings, rocket engine explosions and having to be trucked back to Edwards after emergency landings at Mud Lake, Nev.
On the third X-15 flight, the X-15 broke its back on landing. That would usually consign an airframe to the scrapyard. Not this model. Turns out the X-15s, unlike nearly all experimental aircraft used by the Air Force and NASA, was not constructed from aluminum. The X-15 was built of a tough nickel alloy.
One of the big disappointments to come out of the program came from Hollywood, which in a request for government access and cooperation, promised the movie X-15 a big budget, and a big name cast, including newcomer Mary Tyler Moore. But the moon went down along with the movie budget. After the movie’s release, the Pentagon brass applauded it. Does the acronym CYA apply there?
On a happier note, author Evans gave a shout-out to the women of NASA’s Dryden Flight Research Center (now the Armstrong FRC) who made up the center’s core of human “computers,” at Edwards doing what women in the early space program were celebrated for in the award-winning film, Hidden Figures.