Thomas Perkins - a man with a dream

  • Published
  • By Philip Lorenz III
  • AEDC/PA
ARNOLD AIR FORCE BASE, Tenn. --  When his teacher asked Tom Perkins what he wanted to be when he grew up, the seventh grader shot up his hand and confidently replied, "Either an aeronautical
engineer or an Army Air Corps officer." 

The 79-year-old retired Arnold Engineering Development Center engineer said one of his young classmates' questioned the likelihood of such ambitious aspirations. 

"My friend called out to me and said, 'Hey Tom, you don't have the "smarts" for that,' " Perkins recalled with a laugh. "But I really knew what I wanted, even then." 

Perkins was born in 1929; two years after American pilot Charles Lindbergh made his historic solo trans-Atlantic crossing - an event that brought aviation fever to millions
the world over. Growing up in the shadow of such a landmark event had a powerful influence on the young boy from Bowling Green, Ky. 

Upon graduating from high school, Perkins originally set his sights on attending the Georgia Institute of Technology, better known as Georgia Tech, in Atlanta.
Due to the flood of ex-servicemen applying to the school's engineering program following the end of World War II, his older friends advised him to start college somewhere more accessible. 

Taking their advice, he enrolled at Western Kentucky University in his hometown. Two years later, Perkins transferred to Georgia Tech and during a break got his first introduction to AEDC. 

"I was a junior at Georgia Tech and I had a friend who needed a ride up to Arnold because he had taken a job here," Perkins recalled. "This was in 1951 and I didn't even know this place existed. My friend said, 'Not many people know about it, we're just getting started.'" 

Perkins dropped his friend off at the center's main gate and drove on. 

Upon graduating with a degree in aeronautical engineering from Georgia Tech, Perkins worked at the 20-foot wind tunnel at Wright Field, Ohio. 

"I was working for Dr. Bernard Goethert, who was the head of the whole wind tunnel facility up there," he recalled. "I could hardly understand him - with his broken German. He probably couldn't understand me, but anyhow we worked it out. Doc was a great guy. He later did a lot for both AEDC and UTSI." 

Two months later, Perkins was ordered to active duty in the Air Force, having obtained his commission through the Reserve Officers Training Corps program at Georgia Tech. After going to Lackland Air Force Base, Texas for indoctrination training, he reported
to Keesler AFB in Biloxi, Miss. for airborne radar training. 

"I took airborne electronics and after graduating from that school I went to Korea in 1953 for a year with a fighter interceptor squadron," Perkins said. "They didn't have much in the way of electronics on a fighter plane so they made me an armament and communication officer." 

In that position, one of his responsibilities included bore sighting and ensuring the accuracy of the F-86's six machine guns. He vividly remembers when he and his crew went out to shoot the plane's machine guns and watched as tracer rounds illuminated the cold night sky. This allowed them to adjust the line of fire so that 90 percent of the bullets hit inside a three-foot diameter bull's-eye at 1,000 feet. 

"Our fighter interceptor squadron had the best record in June 1953 - they shot down more MIGs that month than anybody else," he said. 

In March 1954, he was honorably discharged and returned to his family's home in Bowling Green to help his father put in a gas pipeline. He then went to work at Redstone Arsenal in the Army's Ballistic Missile Command at Huntsville, Ala. 

"They put me to work on a drawing board - I wasn't too happy about that," he recalled. "I worked nine months there and then I decided to use my GI Bill to go to graduate school at the University of Michigan. I didn't realize how cold it got there. I think it was as cold as Korea. I arrived there in January, and I didn't see green grass until May." 

Despite the inhospitable weather, Perkins enjoyed his time at the school. 

"The University of Michigan is a very good school for aerospace (engineering)," he said. 

However, after a year and a half, he was running out of money and realized he would have to go back to work. He went to work for Glenn L. Martin in Baltimore. To put things into perspective, Perkins said aviation pioneer Glenn L. Martin had founded the U.S. aircraft company, the predecessor to Lockheed Martin, in 1912.

"That is where I got into flutter work," he recalled. 

Perkins explained that flutter is a self-starting vibration that occurs when a lifting surface, like a wing or a tail surface, bends under aerodynamic loads because the aerodynamic loads overcome the structural damping of the surface. 

"In extreme cases the elasticity of the structure, when the load on it is reduced, causes it to spring back so far that it overshoots and causes a new aerodynamic load in the opposite direction to the original," he continued. "If this continues with enough force and long enough the structure can be seriously damaged or destroyed." 

The company put Perkins to work in the dynamics section and assigned him to evaluate the P-6M SeaMaster. The experience would help to lay the groundwork for his future at AEDC. The SeaMaster was a swept-wing seaplane powered by four jet engines with the body incorporating a new hull design. Some aviation experts claimed the aircraft was the most sophisticated flying boat constructed at the time. 

However, Perkins said design flaws with the aircraft's tail proved disastrous, resulting in two crashes, one of which was fatal for the crew. 

"The second time it crashed was when I was there," he recalled. "We built a flutter model and tested it in the wind tunnel at the University of Maryland. We kept telling the design team that they needed to change the design, take the dihedral out of the horizontal tail, and make it straight, which they finally did. They finally went to a symmetrical fairing atop the vertical tail and a straight horizontal tail, and it got rid of all the flutter problems and air load problems because it didn't have that high down load on it which was caused in the original design." 

From Baltimore, Perkins took an engineering job with North American Aviation in Columbus, Ohio. 

"I worked in the dynamics section at Columbus, Ohio, which is North American's division up there. At the time, they were building F-100s, T-2Js, which was the Buckeye Trainer, and the A-3J Vigilanti. 

Perkins worked on testing the aircraft's ejection seat prototypes while at Columbus. However, as time went by his family needed his help more frequently with the family business in Kentucky. 

"My dad had been sick, and I would have to go home once a month and read the gas meters," he explained. "He had a gas line, and he wasn't able go out and do it. So, I figured I better get closer to home." 

Also, by now, Perkins had fulfilled another childhood dream; he had earned his private pilot's license and owned a plane. He would fly from Columbus to Bowling Green to help his father on weekends. 

"In May 1958, I came down to AEDC when I found there was an opening, and I went to work in the dynamics section at the Propulsion Wind Tunnel (PWT) facility," he said. "I was impressed with the size and ability of PWT - the fact that it had a 16-foot test section capable of going up to Mach 1.6 and the 16-foot supersonic test section that could go from Mach 1.6 to 4.0." 

For more than 30 years, Perkins worked on a diverse assortment of test projects at PWT. He arrived at AEDC when the science of flight simulation testing was still the realm of pioneers in the fields of aerospace and aeronautical engineering. 

Much of the process, from the design of the tunnels, arc heaters, space chambers, and the elaborate supporting structures, had little or no precedent beyond the ingenious facilities and materials brought back from Germany after World War II. 

Data collection was still a primitive, time consuming and cumbersome process that could easily interfere with a test. Early computers were physically huge, extremely expensive and limited in capability. 

Perkins said people often see problems of a failure during a test as an indication of an unworkable situation, an unrecoverable failure and an irretrievable loss of money and assets. 

"I don't see things that way," he said. "Every attempt is made to avoid damaging a test article and the facilities, but it can be hard or next to impossible to avoid sometimes.
Besides, you can learn a lot when a test fails, or even when the model is damaged or even destroyed. That is precisely why we test. It is imperative to know what can and will go wrong to avoid losing lives or a multi-million dollar aircraft or weapons system." 

He described the rigorous process engineers and technicians had used to avoid the damage and loss of test articles, test facilities and supporting infrastructure, saying, "We had strain gauges on the surfaces of the models for measuring both bending and torsion. And also we could take an oscilloscope and put a lead on the bending axis and another on the torsional axis, and when it came close to fluttering you would get a circle on the oscilloscope." 

Perkins said the oscilloscope shows cycles of bursts of activity followed by a dampening of energy before another burst of activity. The goal was to avoid what is called full divergence, indicating imminent destruction of the test article. 

Perkins vividly recalls a test conducted on the X-20 Dyna-Soar, an innovative U.S. Air Force program that ran until about 1960. The objective was to develop a space plane to fulfill a variety of military missions, including bombing, reconnaissance, satellite maintenance and space rescue. 

"Boeing had built a $100,000 model of this space plane," he said. "That was a lot of money back then. It was a beautiful model - they had scaled every little member
of the plane's structure as to what the real one would be like with a fiberglass covering."
Perkins described the structure as appearing "like welded little pieces of steel." 

He saw that the model was starting to flutter and warned the customer. 

Perkins said, "The Boeing engineer said 'let's go a little longer, and take it a bit farther (under the test conditions).' We went a little farther and boom - that was it. It diverged. The whole model came apart, it was fiberglass and steel. We had cameras mounted on the sting support and a camera on each side and one at the top of the test section, so we obtained good movies of the failure. That was in 16T and since the tunnel's compressor blades were made of stainless steel, there wasn't much damage to the compressor." 

In July 1961 he was running a full-scale portion of the Saturn S-IVB panel flutter test in 16T when the C-1 compressor failed. 

"The model had nothing to do with the failure of the compressor," he explained. "All testing in 16T was suspended until the C-1 compressor was fitted with composite
blades. These new blades had to be designed and built which took about three years. Therefore, several project engineers were sent to NASA-Ames to conduct testing in the wind tunnels there." 

Perkins said there were many highlights during his 30-year career
with AEDC. 

"The most interesting series of tests that I was assigned to was the F-111 aeroelastic model tests at Ames 11-foot tunnel in California. I was working for ARO, Inc., at PWT in 1963 when I was sent out for that assignment," he said. 

The model was constructed by General Dynamics in Fort Worth, Texas, proof-loaded with weights to simulate the static load that it would encounter during the wind tunnel test, packed up, and flown out to NASA-Ames at Moffett Field. 

"When I flew out later, I was permitted to land my 1960 Bellanca 260 there and kept my plane in the hangar with test airplanes such as the X-14 and Chance Vought Skyray," he recalled. "The test went very well, but we did get into flutter on the vertical tail and rudder. My return trip to Tennessee was the weekend that President Kennedy was assassinated." 

Someone who remembers Perkins from those early years at Arnold is AEDC Fellow Dr. Bill Baker. 

"When I first came to work here, I was in the same section as Tom and as we began talking, he mentioned his recent marriage and it turned out that we had both married
girls from Starkville, Miss.," Dr. Baker recalled. "His wife, Margaret and my wife went to school together and I played in the Mississippi State University Band with Margaret. Tom and I have been close friends ever since." 

Dr. Baker, who has known Perkins for 44 years, said the two of them worked together on a wide range of tests at Arnold over the years. 

"One of my first assignments in 1964, as a fresh new engineer, was to assist Tom with a wind tunnel test in the 16-foot supersonic tunnel," he said. "We worked together
on other tests for a number of years and I learned a lot about wind tunnel testing from him. 

"Tom also became an expert in store separation and provided analysis of several store separation tests," Dr. Baker continued. "He also led an effort to extract aerodynamic coefficients from store model trajectories obtained from free-drop data. Tom provided key support to the testing of store separation from a generic weapons bay that has become a standard for the development of prediction techniques for weapons bays." 

Perkins said his last few years at AEDC were spent doing research on different types of tests and data basing the test data from the C-17, B-1B and F-15 tests. 

Besides honing his piloting skills over the years, he also devoted much of his off-duty time to supporting the local chapter of the Civil Air Patrol, introducing young people to the world of aviation.