Pregnant Guppy

“It will never get off the ground.” “it’s ridiculous.” “With that large a fuselage and the present tail, it will be unstable.” So the detractors said, and unlike the detractors in most aviation stories, they were right. It was the world’s largest airplane and in many ways the most unlikely, and to one degree or another it fulfilled all these comments and predictions.

The first time the Pregnant Guppy (its peculiar shape gave it the name) took off from California’s Mojave Airport under its maximum weight of 141,000 pounds, in the spring of 1963, it did manage to get aloft, but just barely. After the usual long, lumbering ground run, the landing gear was retracted, but the ship could climb no faster than the hilly ground was rising in front of it. The air speed seemed locked at 128 knots. An awed and expectant silence prevailed in the cockpit, even as the engines and propellers churned away at their noisiest level.

The town of Boron loomed dead ahead. It looked as if the Guppy’s crew would clean it out if they didn’t turn, but a turn might sink them back into the ground. The flight engineer saw that the right inboard engine was giving them trouble. He told the pilot, “Number three is overheating. Can I pull it back?”

“Don’t touch it.”

“But it will burn up!”

“Let it burn.”

To this day some crew members swear that the burning of fuel, with its consequent lightening of the plane, was the only reason the Guppy finally managed to climb. They say a string of skeletons from jackrabbits that died of pure fright runs from Mojave to Boron. After that flight the engineers and pilots agreed to decrease the plane’s maximum weight by 8,000 pounds before anyone took it up again.

This was an almost typical flight in the most unusual aircraft development project since the Wright brothers came out of their bicycle shop. I was fortunate to have flown in the first Guppy as a Federal Aviation Administration engineer observer and later to have served as a test pilot on the Super Guppy and a consultant test pilot on the Mini Guppy’s pre-certification tests. All these years later, the experience stands out as unique in my aviation career.

In retrospect, once NASA’s lunar-landing program got under way, a ship of the Pregnant Guppy’s size became inevitable. It was designed for one specific task: to haul Saturn rocketengine boosters, 40 feet long and 18 feet in diameter, from Douglas Aircraft’s manufacturing site in Sacramento, California, to Cape Canaveral, Florida. Road and rail transport were out of the question, and conventional cargo aircraft could handle objects up to maybe half their size. The only way to take the boosters to Florida was to strap them to a barge and sail them through the Panama Canal. But that took 15 days and required the constant attendance of five engineers, and even so, the parts arrived banged up and corroded from the weather. They were designed to stand vertically and be filled with fuel. When empty, they were like a shell of aluminum foil.

An airplane of sufficient size, if one could be built, would be able to deliver the boosters in under 24 hours with much less damage. So the solution to NASA’s transportation bottleneck was obvious—in concept, at least. Making that concept a reality, however, was so difficult that it took an ad hoc development group, spurred by a flamboyant visionary named Jack Conroy, to undertake a task that from both engineering and financial points of view could best be described as foolhardy.

A fast pace was not new to Conroy. In 1955, as an Air Force pilot, he had set a coast-to-coast roundtrip speed record as the pilot of an F-86 in Operation Boomerang. Ten years later he broke the same record in the Learjet class. But Conroy was never satisfied just to be a pilot. He wanted to be a mover and shaker in the aviation world. He was not trained as an engineer or test pilot, but he was a visionary. He had an innate grasp of what was possible in an airplane that no college degree could convey.

In the early 1960s all sorts of wild schemes and ideas were flying about the aerospace industry, as well as inside NASA, for ways to transport rocket stages. The idea for the Pregnant Guppy came from Lee Mansdorf, a businessman who bought and sold aircraft, and was midwifed by Conroy. In 1961 Mansdorf hired Abe Kaplan of Strato Engineering, an aircraft design team, to draw up a proposal for NASA. They had only three days to prepare for a meeting with Wernher von Braun, NASA’s rocketry chief, but von Braun expressed interest (though he made no commitment), so they started serious work on the design. Mansdorf had been buying up surplus B-377 Stratocruisers and KC-97 Stratotankers, both made by Boeing, and it looked as if they could be altered or recycled to create the plane he envisioned.

The two men formed Aero Spacelines, Inc., in Van Nuys, California, with Conroy as chief executive officer and Mansdorf as vice president. Lloyd Dorsett of Dorsett Electronics in Norman, Oklahoma, who provided the financing, was the company’s president. Strato Engineering furnished most of the design talent, while On Mark Engineering handled construction. A Stratocruiser was flown in to be converted into the Pregnant Guppy’s main airframe along with another one to provide parts.

The plan had three phases. First, lengthen the Stratocruiser’s fuselage by 16 feet 8 inches with segments from the second airplane and test-fly the result. Second, build the enlarged fuselage, 19 feet 6 inches in diameter with internal bracing, over the old one and test-fly that. Third, take out the bracing and cut away the old fuselage.

When the first test flight revealed that retracting the flaps caused buffeting, Conroy hired Irv Culver, a well-known aerodynamicist, to design a fix to smooth the flow at the wingfuselage juncture. According to Sandy Friezner, a consulting engineer on vibration testing, “Irv knew Jack’s stubbornness and penchant for going at things his own way, so he told Jack, ‘If you don’t do what I tell you, I will charge you a lot of money. If you do, the price goes down.’ Since there was not nearly enough money to do a wind-tunnel test program, Irv took a model with silk strings attached and put it in front of a fan. Using cardboard and modeling putty, he came up with a shape that was then drawn and used.”

This was a classic example of how things got done at Aero Spacelines. An expression often used by designers describes this type of work: “Build to fit. Draw to match. Paint to cover.” Conroy was fond of saying, “It’s amazing what you can do without paperwork. … On most aerospace projects, any of our planes would have taken three years.”

Money was always a problem. The original financing came from just one person, Lloyd Dorsett, and it soon ran out. Conditions reached the point where Conroy no longer owned his house, cars, or furnishings. Still the project staggered ahead. “Conroy was a stubborn man in the face of adversity,” said Bob Lillibridge, who headed up the construction on most of his airplanes. “He would not give up. He was not a nice man, but he was interesting to work for and had great ideas.”

Jack Conroy was full of bluster and hype, but he backed it up with vision, determination, and a solid commitment to his goals. He also knew the value of publicity. No matter whether you were a famous scientist like Wernher von Braun, a reporter like his longtime friend Clete Roberts, or a famous test pilot like Herman (“Fish”) Salmon, if you could move his project forward, he would charm you for as long as was necessary to enlist your aid. In a single conversation he could bluster, bluff, plead, cajole, threaten, intimidate, and compliment. He was a chameleon; whatever it took to reach his goals, he could change his approach and mood to fit.

He hired the best people he could afford. He appealed to their ego, patriotism, sense of accomplishment, or desire to make aviation history—whatever was necessary to get them on board. Then he pushed them to their limits. Kirk Irwin, who took over a few years after Conroy left ASI, said, “Jack Conroy was a good friend to whom I wouldn’t loan a dime. He believed in the unachievable. We need people like him.”

I watched Conroy set up goals and schedules that were impossible to meet and then at the last minute, when failure was imminent, unveil Plan B, which saved the day. Very seldom did he fail completely, but he did cut it close. On the morning of the first flight of the Mini Guppy (a scaled-down later version), Larry Engel and I parked the airplane in front of the media troops. On our right side, the cameras were rolling and flashbulbs were popping. On our left, mechanics were tearing into the wing tanks to repair a leak. That afternoon the plane left for the Paris Air Show.

The lengthened but not yet enlarged stratocmiser fuselage flew only twice. Running out of time and money, Conroy decided to press on. This decision made for considerable drama. Many said the large fuselage would make the airplane unstable and create too much drag. Only a few wind-tunnel tests had been run, and they were inconclusive. The Federal Aviation Administration placed numerous restrictions on the first flight from Van Nuys to Mojave. Aero Spacelines had to locate and avoid each hospital and school along the flight path—and the police cordoned off the streets south of Runway 16, while fire departments called out trucks to stand by all along the route.

A huge crowd gathered at the airport. Bets were placed on the outcome. That inaugural flight, on September 19, 1962, was a disappointment for those predicting disaster. With Conroy himself at the controls along with Clay Lacy (co-pilot), Bob d’Agostini (flight engineer), and Bill Cuff (mechanic), the plane lifted off easily and passed high above the Sky Trails Restaurant, where most of his comrades and the airport crowd had gathered. By September 24 it had logged 8 hours and 40 minutes’ flying time. On September 26 Conroy asked for and received FAA permission to fly the Guppy to NASA’s facility at Huntsville, Alabama, to visit his only customer.

After listening to Conroy’s pitch, von Braun, a pilot himself, climbed into the right seat for another flight. Here is Conroy’s account of what happened next: “After we got airborne, I turned the controls over to him. Then I signaled the flight engineer to slowly reduce power and then feather [turn off] the left outboard engine. Dr. von Braun didn’t even notice it. Then the flight engineer reduced power and feathered the left inboard engine. By that time Dr. von Braun knew something was different, but the plane was still flying well on two engines with a full load. No one has ever told me since then that the Pregnant Guppy wouldn’t fly.”

I discussed this story with Jack Pedesky, Conroy’s test pilot on a later Guppy model, and we agreed that it contains a generous helping of Conroy hype. If the plane was full of fuel and had 20,000 pounds of ballast, as he says, then it did all this while weighing 151,000 pounds, well over the 133,000 that was set as the maximum operating weight. We decided that Conroy probably signaled the flight engineer to crank the engines back up before the speed and altitude bled off. And someone must have been standing on the right rudder if there really were two engines out on the left side.

Bob d’Agostini, the flight engineer on this particular trip, confirmed this and said, “Not only that, but the oil level was so low we couldn’t unfeather. I had to go below and stoke the central oil replenishing tank with 15 quarts of oil. When I returned, Jack was distracting von Braun while the cords on his neck stood out from the effort of holding the rudder. I don’t know if the good doctor realized the mess we were in, but he appeared to be enjoying the flight and was impressed with the Pregnant Guppy.” After this flight a dorsal fin was added for extra stability.

Conroy received a letter of intent and eventually a contract from NASA that he could wave at his creditors to stave them off. He clashed frequently with his backers. At one point they barred him from entering his office. He secured a court order, and for a while two sets of guards faced off against each other at the plant like gunfighters at the O.K. Corral. His opponents finally caved in.

Once the internal bracing and the old fuselage were cleared out, leaving a plane with an inside diameter of 18 feet, a team of NASA engineers loaded an instrumented dummy third stage of the Saturn IVB launch vehicle in the gaping hole of the separated fuselage, right behind the wing. Thirty-two bolts had to be torqued to lock down the separation after it was closed. Conroy said, “The NASA people were concerned that the mechanic on this procedure might slip up. They were reassured when I told them that he goes on board with us each time we fly.”

The cockpit of the Guppy was essentially unchanged from its earlier days as a Stratocruiser. A pilot entering it would find the same maze of gauges controlling the four Pratt & Whitney R-4360 “corncob” engines and all the subsystems. The greenhouse of glass covering the bulbous nose gave a feeling of expansiveness not found in present-day jets, which are more concerned with high-speed aerodynamics. The smells were a cross between a machine shop and a vintage Mercedes: oil, hydraulic fluid, old leather.

The engines were not the most reliable. Jim Ashley, the FAA test engineer assigned to evaluate the plane, recalls that engineout climb or cruise tests often resulted in engine-out landings when the inoperative engine would not restart. During stall tests on a later model, he walked back to observe from the tail area. “Once was enough,” he says. “The fuselage looked like a willow basket in a windstorm, twisting, racking, and creaking. I returned to the cockpit and tried not to think about it for the rest of our flight.”

There was a great deal of concern that the bulging fuselage might disturb the airflow and make the tail ineffective at high sideslip angles, such as in a crosswind or when two engines were out on one side. Surprisingly, the forces turned out to be acceptable. In pitch and roll, the Guppy had to be wrestled around like a big truck with no power steering, but that was to be expected. The FAA made cursory tests and gladly handed it off to NASA, whose pilots ran further checks. In mid-September 1963 the Pregnant Guppy made its first payload flight for NASA, only one year after its initial test flight. When finally retired in 1974, it had logged more than 6,000 hours.

Even before the Pregnant Guppy made its first flight, however, both NASA and Conroy knew they needed a roomier plane. So Aero Spacelines created the Very Pregnant Guppy, with an inner diameter of 25 feet and a cargo compartment 94Vi feet long. This monster, designed for Apollo rocket stages, could easily swallow a DC-10 fuselage. Its volume of 49,750 cubic feet was five times larger than that of the standard airplanes of its day. You could have held an Olympic pole-vault competition in there.

Four KC-97 airframes were cannibalized to built it. For loading, it used a swing nose that pivoted 110 degrees on two 600-pound hinges. The power problems of the original Guppy were resolved when, at NASA’s request, the Air Force made available four experimental engines with the most powerful turbines of their time, producing up to 6,000 eshp (equivalent shaft horsepower). On my first entry into the cockpit, I asked the flight engineer what the red lines on his reference power chart were for. He replied, “Oh, that’s like war emergency power in the old World War II recips [reciprocating engines]. If you shove it up there, it will produce an enormous power, but nobody knows for how long.” The Very Pregnant Guppy soon became known as Super Guppy.

The Guppys were a lifesaver for NASA. Without these unique aircraft, we would never have made it to the moon before the end of the 1960s. From Gemini to Apollo to Skylab, they flew more than two million miles carrying outsized components. When NASA finally ran through all its spare engines and propellers, it retired the original Super, which is mothballed at the Pima Air Museum in Arizona. In San Francisco, a group of enthusiasts is raising money to return it to a museum at Santa Barbara.

Aero Spacelines was taken over in 1967 by the Unexcelled Corporation, which subsequently changed hands twice and dissolved. Conroy left and used money from his stock to create a version of the Canadair CL-44 modified for oversized cargo service. Azerbaijan Airlines became its eventual owner. He later developed a short-takeoff-and-landing plane called the STOL Lifter and a turbine-engined conversion of the DC-3. None of these proved commercially feasible.

Unexcelled built two prototypes of smaller versions of the Guppy called Mini Guppys for smaller-scale commercial use. The turbine version crashed in a test flight; the other was bought by Erickson Sky Crane in Oregon and used for years to support logging operations. When it became too hard to maintain, it was retired to the state’s Tillamook Air Museum.

Meanwhile, the Airbus consortium realized the Super Guppy could solve the problem of moving fuselage and wing sections of its huge A300/310/320 passenger airliners around Europe and contracted with Aero Spacelines for four planes. These had a wider floor than the original Super Guppy, 13 feet instead of 8, and an even longer cargo area. They used Allison 501D22C engines of 4,680 eshp, and unlike the Super Guppy, which had a restricted classification, they were certified by the FAA as normal commercial aircraft. The first one took to the air on August 24, 1970. Eventually the aging Guppys were replaced by Airbus’s A300-600 ST Beluga, a “Super” Super Guppy based on the A310 airframe.

Three of Airbus’s four Super Guppys were retired to museums in Europe, but the fourth was returned to NASA in a barter arrangement for payload space on the International Space Station. Its first load for NASA was a 747SP fuselage to be used in the Sophia flying-telescope project. More than 30 flights carrying space-station components have saved NASA at least $40 million over what it would have cost to contract them out.

When Tracer built this plane, it needed spares for a subassembly of the lower aft fuselage. None could be salvaged from Mansdorf’s collection of surplus planes, so Tracor persuaded Allen Paulsen, the head of Gulfstream Corporation, to sell them that section from the original Pregnant Guppy, which he owned. Because of this, a part of the very first Pregnant Guppy, from the early 1960s, is still being used in the space program as an organ transplant in NASA’s Super Guppy.

Jack Conroy died of cancer in 1979, but before he went, he wrote the script for his own funeral. The airport at Camarillo, California, closed for 20 minutes for a flyby of his creations. He had left instructions specifying the order of each airplane and the pilots who would fly them. Clete Roberts presided and observed Jack’s specific wishes for the food served and the kind and quantity of liquor. Though he isn’t around to see the latest Guppy versions, Jack Conroy would certainly take satisfaction in the fact that the spawn of his ideas still supports the space program and the competition among the giants of aerospace.