The Navy’s first airship—a nonrigid, or blimp— is delivered in 1917. Ideal for over-water reconnaissance, early designs could loiter aloft for 24 hours. Rigid airships, though, possessed a phenomenal endurance. The USS Macon (ZRS-5), cruising at 55 knots, could range nearly 6,000 nautical miles for strategic search. Its longest flight, in July 1934, had the ship in the air nearly 83 hours—more than three days.
When the last of the great rigids are scrapped in 1939- 1940, the blimp comes into its own. New designs compile a superb record of convoy escort and antisubmarine warfare (ASW) during World War II. Following demobilization, wartime designs are modernized and, in 1947, a prototype airship authorized—the “N” series (later ZPG-2). The aircraft is intended to meet Navy specifications for a large, very long-endurance ASW platform.
The model’s most novel feature is the mounting of two power plants within the control car, instead of outboard, on outriggers. The ship, moreover, is intended specifically for one-engine operation, a feature that offers exceptional on-station economy. During normal operation, each engine will deliver power through a long drive shaft to its propeller, but an interconnecting clutch will enable a single engine to drive both props.
Since a habitable environment is crucial, a two-deck car is provided. Work spaces are below; the men will mess and sleep topside. By military standards, living conditions are unusual: a fully equipped galley, a sink and serving counter, food storage. There is a even a wardroom and adjacent lavatory and bunk spaces.
In June 1952, N-l is ferried to the Naval Air Station (NAS), Lakehurst, New Jersey, for an exhaustive preliminary evaluation conducted by a board of inspection and survey. Meanwhile, in Ohio, the first production ship, BuNo (bureau number) 126716, is completed. In October 1953, “716” is delivered to the Navy.
Its trials prove intriguing, particularly the operating efficiency of the 800-horsepower engines at various static conditions, that is, with the aircraft’s operating weight variously “light” or “heavy.” It may be possible, the board concludes, to exceed the endurance guaranteed by the ship’s manufacturer, Goodyear Aircraft. In-flight procedures are devised to explore getting the most from the engines.
Commander M. H. Eppes, senior member of the Board of Inspection and Survey, recalls, “It was during one of these bull sessions that the discussion of the extreme economy of the engines under certain conditions led to the proposal for a test of the ultimate capability of the ship to stay in the air. . . . This endurance theoretically would be used to occupy an assigned station for carrying out an ASW or AEW [airborne early warning] mission.” Official blessing is secured.
In the realm of lighter-than-air, long flights were an operational reality. Unlike airplanes, which require continuous use of engines, an airship floats by virtue of its contained helium, conferring exceptional lift and endurance. The power plants propel the craft forward and proffer some dynamic lift from the huge envelope or “bag,” which acts as a crude airfoil. The engines are used also to adjust speed—from a maximum down to literally zero.
716 logs two record tries. On 4-7 April 1954, it meets a tropical depression between New York and Bermuda. As it heads into the blow, maintaining position bow on, violent rain and turbulence buffet the aircraft. Fuel consumption climbs. Then a hydraulic leak in the control system forces an abort. Though disappointed, the crew have gained faith in their ship. They resolve to try again.
Monday, 17 May 1954- Last-minute loading is concluded. Every possible gallon of fuel has been pumped on board—about 2,650 gallons (slightly more than 15,000 pounds). The one-million-cubic-foot envelope is 97% inflated; the balance will accommodate daylight temperatures, which will expand the ship’s helium. For the “mechs,” more than 100 pounds of tools and other gear have been stowed on board, along with spark plugs, miscellaneous fittings, and extra oil. As well, approximately 1,800 pounds of fresh and frozen food and 115 gallons of water will sustain the flight crew.
Fourteen volunteers will make the sortie. Thirteen are seasoned naval aviators. Accepted as a member of the crew, Goodyear’s civilian mechanic, Edgar Moore, who has been with 716 throughout its construction and testing, will stand watches with his shipmates.
A briefing is held at 0530. Fog shrouds the station. When fueling is completed, the airmen clamber aboard, dispersing along the 83-foot-long car. The engines are warmed and final preflight checks concluded. Lieutenant Commander Ben Levitt, senior pilot, occupies the port- side seat. One of the best in the business, he is the brain behind most of the board’s structural and dynamic tests. Slowly, he advances the throttles to full power.
About 6,000 pounds “heavy,” 716 will require a long take-off roll. It accelerates, rolling to take-off speed like an airplane. When heaviness is being carried dynamically, Levitt eases his wheel, and the mat drops away. Take-off time: 0632 EDT.
The blimp will remain continuously airborne for the next 200 hours.
Today’s overcast is a blessing, reducing the need to valve helium. At this stage, every ounce of lift is needed. But the sun begins to break through. Mere hours out, the pilots are obliged to valve to avoid overpressure. And to maintain altitude, extra power must be applied. The penalty, of course, is fuel. A favorable rate of consumption must await lightened ship, that is, burned-off fuel and increased “superheat.” (When a ship’s helium becomes warmer than the surrounding air, its density decreases and lift increases.) For now, helium losses cancel burned fuel. Airspeeds up to 47 knots are required to maintain a 10° nose-up attitude, which eases static heaviness. During the 1000-1200 watch, the starboard engine is cut but restarted: the ship is still too heavy. Ironically, helium must be valved. The pilots want to avoid altitude, to keep 716 in cooler air near the water (at about 500 feet) to limit expansion of the helium.
An airship is exquisitely sensitive to its medium. Thus, a blend of conventional plane handling and ballooning is required. The gas laws that govern control and condition are uncompromising. As one aviator quipped: “Normal airship flying is a constant battle with Charles’s Law and Boyle’s Law,” which state, respectively, that the volume of a gas increases with increased temperature, and decreases with increased pressure.
Aft and to starboard, on the northwest horizon, the New England coastline disappears. The over-water run toward Bermuda has begun.
Abruptly, the first crisis: the Loran gear is inoperative. In 1954, radar coverage does not extend far to seaward; no one on shore is following them. In terms of navigation, the airmen are strictly on their own. Relying on celestial navigation and dead reckoning for a week would be foolhardy. The Loran can tell them precisely where they are— when it is working. Compounding matters, the receiving stations (Lakehurst among them) evidently are not receiving their signals. One of the radiomen, Chief William Koll, sets to work on the Loran. Across the isle, Chief Paul Richter, the radioman on watch, attacks the radio problem. During the 1600-1800 watch, the Loran begins getting good fixes and voice communication is reestablished. The Loran gear will remain temperamental, but, for the moment at least, the mission is out of jeopardy.
At sunset, cumulus buildups float ahead. The southward heading is changed, then resumed, toward the weather ship station Hotel, off Cape Hatteras, North Carolina. The Loran quits again, leaving Hotel as the only fix they have. As yet, both engines—and a 34-knot airspeed—are needed to hold altitude.
The pilots play with results of reducing power. During the 2200-2400 watch, airspeed is cut to 33 knots. Fuel consumption is 174 pounds per hour, calling for a switch to single-engine operation as soon as static condition allows. At midnight, the navigator on watch, Lieutenant Commander Raymond Porter notes, “We need an over- cast sky tomorrow.”
Current elapsed flight time: 17.5 hours.
The aircrew settle in. The in-flight routine resembles that on board a surface vessel: the watch is rotated every few hours. (Five pilots are on board.) The off-duty section usually retreats topside, for mess, a chat, or to join the wardroom’s endless cribbage game. Some play checkers, read, write letters. The most nettling inconvenience is the ration of fresh water. Showers become the stuff of fantasy.
In the early hours of 18 May, the starboard engine is cut. Hotel is abeam in moonlight at about 0230. Morning weather is heaven sent: a thin stratus overcast, perfect for reducing superheat. Fuel consumption is reduced gradually, to 95 pounds per hour, then to 84, then 74. At 1600, Bermuda is sighted. Airspeed is cut to 22 knots. Usage rate goes to 58 pounds each hour, the lowest so far. The forecast is received for the routes to Nassau and San Juan.
A lovely landfall spreads away. A mail drop, however, is nearly disastrous. Over Bermuda’s Kindley Field, forward speed is lost in a turn; 716 almost goes in. Emergency power saves the mission—but they have come frightfully close to delivering 14 males onto the island instead of mail! The blimp presses south. Next landfall is Puerto Rico.
At midnight, flight time is dutifully logged: 41 -5 hours.
The Bermuda-Puerto Rico leg conspires against the aircraft—two and a half days that test both airmanship and stamina. Headwinds frustrate progress; frequent squalls demand detours; wind shifts bedevil navigation. The Loran continues irascible. Vacillating static condition exacts full attention from the flight deck. The mental strain on all hands proves terrific.
Minutes after noon on 19 May, the starboard engine is started and the port power plant stopped for a routine 60-hour check. When the mechanics conclude their work, the engine is restarted; its companion is secured. Preparations for evening chow begin to get under way. The next decision: do they push to San Juan or proceed to Guantanamo Bay? A seagull is sighted, the only living thing since Bermuda.
Shortly before midnight, a new crisis rears its head. One of the fan blades on the refrigerator snaps. Most of the food—and the mission—are again at risk. Petty Officer John Reinhart, one of the riggers and the cook, sets to work on the problem.
Flight time: 65.5 hours.
Minutes after sunrise, a ship is spotted. This chance rendezvous cannot be savored; preparations are under way for the first water pickup. The operation is time-demanding and, depending on conditions, delicate. And the maneuver requires both engines—and a lot of power. But droppable water will come in handy after sunset, when the ship sheds buoyancy. A fabric bag is lowered using a winch mounted in the stern. Contacting the sea, the bag is dragged ahead, hauled back up, and its contents transferred to the ballast tanks. Twelve hundred pounds are retrieved in about 30 minutes, providing an unusual show for the merchantman.
Good news for breakfast: Reinhart has improvised a compressor blade from a coffee can, and a radar blower is cooling the refrigerator. The ship pushes into a 15-knot headwind. All on board are anxious for a glimpse of anything besides empty ocean.
Total time at midnight: 89.5 hours.
It is Friday morning, and the Loran remains hit and miss. San Juan is near, and offers a helpful bearing. Dawn finds all hands at the windows. Dead reckoning and the radio fix put Puerto Rico a scant 18 miles south. Four- thousand-foot mountains, they all know, loom near, yet the horizon holds only cloud and haze.
At 1010, land is sighted. Twelve minutes later, as if to underscore the moment, the flight passes the 100-hour mark. Spirits soar and the log is pleased to record, “Beginning the downhill trek.”
At dawn the next day, 716 is island hopping toward Nassau, where it makes a mail drop. At 1445, departure is taken for Key West via Miami. The sparkle of Florida’s famed Gold Coast is in view around 2200—the first mainland sighting in five days.
Thunderstorms surround the airship. It is decided to hold off Miami until these dissipate and steam into the wind, moving off to avoid thunderheads and downpours. This proves an unpleasant business—fighting to hold position without consuming undue fuel. But here they will loiter.
Despite a buffeting early on Sunday, morale is high. And why not? In the morning, this crew will equal the record for unrefueled flight. Reinhart breaks out the “family silver and linen napkins” for a celebratory turkey. The strain, though, is evident. All hands are tired, grubby, and eager for a shower. The same stretch of beach is now tiresome.
Flight time at midnight: 161.5 hours.
Sunrise, 24 May. The record will be theirs. About 2,200 pounds of fuel remain for 38 more flying hours. Following a ballast pickup, the pilots prepare to turn inshore. The orbiting blimp has been invited to join an air show and to drop mail. Over Master Field, the Marine Corps station near Opa-Locka, Florida, one bag is released.
Thirty-five minutes later, at 0850, the standing record of 170.3 hours is equaled. Word is relayed to the tower, which is asked to contact the public information officer. Two low passes, for news pictures, are requested. A chopper comes up for additional shots. And a message is received from Key West: hold in the Miami area. A radio interview with newsmen in the tower is held. Living conditions on board are “good,”
Eppes tells reporters, citing some of the in-flight amenities, such as “excellent food” and the socket for the electric razor.
The only problem, he chuckles, is the shortage of water for washing: “We all need a lot of deodorant and shaving lotion to stand each other.”
But conditions are turbulent. At 1358, 716 receives clearance to cease its hold; it may depart for Key West. The first message of congratulations is received.
Following a speedy downwind run, 716 checks in at the naval air station on Florida’s Boca Chica Key, receives weather information, and requests permission to hold in the area. That evening, the crew savors news broadcasts over WGBS Miami.
At 0513 next day, the existing record is exceeded by 10%, thereby establishing a new official record for unrefueled flight. A few hours will be added before touchdown— a luscious prospect—now slated for 1430, 25 May.
Sunrise finds the blimp holding station east of Boca Chica Key. For the first time since liftoff, “George,” the autopilot, has taken over completely. For Levitt, the navigator on watch, this is the most enjoyable watch of all. A pot of coffee is brewed from some bootleg water. It tastes terrific.
The ship is given a thorough cleaning. All hands “shower” and shave (using two cups of water each) and don clean uniforms. Finally, the idle engine is started, the aircraft worked into position. At 1436, landing gear again meets U.S. soil.
Official flight time: 200.2 hours—nearly eight and a half days of self sustained, unrefueled flight.
Among the well wishers are local naval personnel, the press and photographers, dignitaries, and representatives from Goodyear. “Innumerable” still and movie pictures ensue. The pilots are shunted to the squadron ready room for a press conference. Crewmen are ushered to the bachelor office quarters and received in royal fashion. Among the attractions: the first shower in nearly nine days.
Eppes will receive the Distinguished Flying Cross and, later, the 1955 Harmon Trophy for Aeronauts. Each crewmember is awarded the Air Medal—including Moore, the first civilian ever to receive the honor. That first shore- side evening, “a hell of a party” honors the flight team.
Two days later, Key West is put astern. After 22 hours, 716 hangs again over Lakehurst. On the mat, an immense “V” of assembled station personnel greets the returning ship and crew. Eppes’s enthusiasm and Levitt’s engineering savvy were indispensable, but all hands contributed. More than once, resourcefulness had saved the mission. Levitt may have said it best: “It was a team effort and everyone was on the team.”
In March 1957, another ZPG-2 completes a transatlantic circuit: east to Europe, a jog south to Africa, return leg to the States. BuNo 141561, Commander Jack R. Hunt command pilot, hangs aloft for 264.2 hours—11 full days—logging the longest airship flight ever: 8,216 miles.
The ZPG-2 will be the primary lighter-than-air platform of the Cold War: 12 production ships, along with AEW versions, are delivered. But the unique potential of this singular platform is never exploited fully. In June 1961, the Navy announces its lighter-than-air program is through. Ironically, it is Captain M. H. Eppes, commanding officer, NAS Lakehurst, who receives the order to deflate and store the last operational airships in the U.S. Navy.