Ground Handling Evolution

gh-1Ground handling of airships, like their ancestral balloons, was originally based on manpower alone.  Larger ships meant more manpower, with its associated labor costs. One of the earliest developments in handling came from Count Ferdinand Von Zeppelin, who commissioned construction of floating hangars (shown at left below, Manzell #1 for LZ-1).

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Used for several ships, the hangars could weathervane so the ship and hangar were automatically aligned for egress. Tide and current were not so much a problem on the Lake of Constance but the line-handling boats were somewhat difficult to coordinate. The concept was abandoned and the hangar moved ashore, but the need to align with the wind remained.


gh3Years later the American Navy got around to copying the floating hangar concept. From the few flights and handling of Pensacola’s Dirigible, Non-Rigid #1 and “DN-3” Americans learned the same lessons.  The hangar was moved ashore. (Above extreme right, the hangar showing damage from a 1922 hurricane. Note the many roof vents, to insure a hydrogen filled non-rigid could be ripped safely inside.)


gh4The ability to weathervane so ship and shed were aligned with the wind was so desirable a complex rotating shed was constructed near Berlin (1910 photo, above left).  This idea evolved into a twin rotating shed during WWI (above, center) and eventually a plan to build a very large rotating shed to connect hangars at what was supposed to become the main Zeppelin hub in Frankfurt.  However, the method for moving rigid airships in and out of fixed hangars was at first dependent on large numbers of handlers… and calm conditions. On USS Shenandoah’s first cross-country trip, the airship was held on the St. Louis Air Races grounds by crews alone.


The British were the first to recognize the airship need not be docked every time.

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Engineering a male/female nose “plumb bob” / “flower pot” mating setup, they developed the tower (or “high”) mast with good result (R.33 shown at extreme left). The Americans copied the idea. A standard mast and site was developed (supporting ZR-1 at North Island, California, center photo) which was duplicated in several locations, eventually evolving into the “Class B” mooring bases. Access to the ship involved getting to the top of the mast and stepping from the platform to the bow door (photo).

The mast plan evolved into heavier, permanent structures plumbed with gasoline, water ballast and lifting gas lines, providing shore power, and equipped with monstrously powerful winches. The Army and Navy built expensive tower masts at Scott Field, Illinois and Lakehurst, New Jersey, respectively. The British built elevator-equipped tower masts and were well on the way placing them in major cities throughout the Empire. Henry Ford even built one of his own, masting the Army RS-1 and Navy ZR-3 (extreme right, above).  A tower mast was planned in for a building in Chicago and one was built atop the new Empire State Building (shown under construction, home page).


la-patokaThe former oiler USS Patoka was the ultimate mobile support base in protected harbors,  providing all airship needs, including a renewable supply of hydrogen via an onboard generator. The generator was never used, though most of Patoka’s onboard Texas helium was once expended refilling USS Akron following a bungled California mooring. Most of the known footage of USS Patoka’s LTA  operations are included in our raw footage DVD “USS Los Angeles”and the second and third chapters of ourAirship History Series.


While impressive looking,  while at the tower masts provisions that could not be piped had to be hand carried through the bow hatch. The ship had to be “flown” at the mast to prevent too many reoccurrences of dipping the lower fin into the surface. Worse, NAS Lakehurst’s tower mast was the scene of an unusual combination of air currents that once rotated, spun and tilted to make the ZR-3 appear to stand on its nose, with minor damage to the cover from falling objects punching through.

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Lakehurst engineers introduced various constructions of shorter “stub” masts that eliminated many of the tower’s problems. (For ZR-3, they also built ground reinforcement girderwork for the center engine car to carry the loads associated with adding their “taxi” wheel, seen here at the “mooring out” circle, a tamped-down dirt track for the wheel to ride while moored out.)
During the ZR-3’s extended deployment to the Caribbean in 1928, she participated in exercises centering around the Panama Canal. The Los Angeles used the Army’s France Field (photo), since Naval Air Station Coco Solo, with its standard steel hangar for non-rigids, did not have enough cleared area to accommodate the rigid airship.  A simple weighted dolly brought in from Lakehurst (photo) was used to discourage kiting.


Though it is hard to verify with the grainy photos available, the literature supports the belief it was the San Diego mast that was dismantled and re-engineered to a lowered height at Mines Field, Los Angeles, California, for the landing of the Graf Zeppelin during its 1929 world flight (photo).

Later, a sectional steel mast, shipped from Lakehurst, was used by the ZR-3 at the September 1929 National Air Races in Cleveland. (The mast served as the final pylon for the air races.) No other particular ground improvements appear to have been done at these temporary sites.

The only way to reduce the cost of handling large rigids was by cutting back on required manpower. Lakehurst again pioneered the mobile mooring mast, first one towed by a WWI tank, to manage the bow while a reduced number of men could swing the stern about.

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Rails cast in the hangar floor were extended outward to accommodate side trolley cars that gently held main frames in line as the ship egressed the sill (diagram). For the transit, the lower engine car rode a centerline rail dolly (photo).

The adjustable mast was built to accommodate the larger ships thought to have been coming, and in fact the system handled the Graf Zeppelin just fine.  The compacted dirt mooring circle was replaced by a circular rail track, which managed both a stern rider car and later the new forward yaw winch cars. The stern could weathervane by pushing the stern  car along the track, but the trolley wheels prevented its lifting upward.  Our DVD “Airship Handling” begins with the earliest known footage of this evolution, and most of the mast footage available is included on our silent footage compilation DVD, “USS Los Angeles.” Photos also show what appears to be a very tall portable mini-mooring mast in photos from the 1930s; this mounted an anemometer at such a height as to check winds to be encountered around the ship’s upper keel and top stabilizer fin.


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With the ZRS contract, Goodyear-Zeppelin beefed up with a non-adjustable design. Their version of a tripod mast was self-propelled . Their much heavier side winch cars  (photo, left) clamped over the Airdock’s docking rails. Their non-adjustable mast was a poor fit for smaller ships, as seen when LZ-127 visited Akron (center). Lakehurst greatly improved and self-propelled their mobile mast design (extreme right with ZRS-4, note open bow door) in response to the arrival of the ZRS ships, the taller mast easily handling both Akron and later Macon. The literature discusses the idea of an experimental stern mooring mast, and drawings were produced, however the idea was not pursued.


The ultimate ground handling system for transiting an airship to and from the fixed hangar axis, and aligning it with the wind, was developed by a Navy-contractor team lead by LT Calvin Bolster and Wellman engineering.

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An 89-ton “stern beam” (photo) was constructed and equipped with dual sets of railroad wheels. One set was aligned with the hangar’s original docking rails. Straight in or out of the hangar, “Spreader gear,” a system of wheeled pipes connecting mast and beam (diagram), prevented the flying-weight airship from carrying the beam’s load when transiting from hangar to circle. Once over the circle, a second set of wheels at 90 degrees to the first, built with the same arc as the mooring circle, were lowered as the first set was retracted. The beam then rode that track to allow the tethered tail to be aligned with either the hangar or the wind.  The massive beam was pulled against even the strongest winds by a specially built 132-ton locomotive, also visible in the photo.  Once aligned with the wind, the bridles securing the tail to the beam were removed, the tail floated upwards and the beam pulled clear. Depending on mission status at that point, either the riding-out car or a taxi wheel or the flight bumper bag could be attached to the lower fin. These and other details are included in James Shock’s book, “American Airship Bases and Facilities.”


extendedThe largest and most advanced mobile tripod mast was finished at Lakehurst after Macon left for California.  The new Wellman mast was 80 feet on a side, 75-feet tall and was powered by an 8-cylinder engine.  The mast could travel both a straight line or a circular path. Its huge simultaneously-extending sections could rise to 160 feet and its powerful winch was rated to pull the largest airships’ mooring spindle into its cup. Never photographed as being used for mooring so extended, its theory supported the American penchant for the so called “high” landing or “flying moor” harking back to the tower mast days. Since rigid airships at the time had no wheels and would probably be arriving on the light side, this technique was thought to be safer for the ship.  (The real answer, already proven with non-rigids, was adding wheels to the airship.)


5-high-tailWhen Macon arrived at Sunnyvale/Mountain view, the complete system of telescoping Wellman mast, stern beam and spreader gear had been duplicated and was waiting for her. Since the new hangar was aligned with the prevailing winds, there was no need for a second circle; Macon would land and take off from the railroad circle fairly close to the hangar. The photo here shows a “flying moor” in final stages. Off-duty watch and water ballast was sent forward until the spindle was locked in the cup, then shifted aft until the tail lines could be grabbed by the line handlers and the tail brought safely onto the riding out car or stern beam. An edited film of Macon’s handling cycle, shot by noted photographer Carroll who’d flown aboard, is included in our DVD “Airship Handling.”  This film was packed with the April 1935 “Macon post-mortem” report forwarded to the Bureau of Aeronautics with the recommendation a sound track be added to make it a more valuable reference for ground handling operations.


That Macon post-mortem” report specified the late practices which allowed faster operations with less manpower and margin for error. These included launching the stern directly from the beam, and landing the stern directly to the beam, without the intermediate step of using the riding-out car. This utilized a new type quick-release to supplement the four hold-down clamps remaining. It suggested leaving the ship on the mast-spreader gear-beam system the entire time it was on the ground and in the hangar, using their fore and aft weighing-off scales to determine static condition at any time. The report called out the Sunnyvale-developed system of “capstan yaw guy winches mounted on circular track mounted on the base of the telescopic mooring mast to replace man-power on the yaw guys.” Also seen in the film, “use of small hand-car type of locomotives for shifting the riding-out cars on the circular and straightaway tracks before, during and after the mooring operations.” The report suggested retirement of the toggle-equipped spider lines in favor of a single rope with ‘monkey fist’ knots every six feet. It also emphasized better training, communication and signaling.


In support of the Graf Zeppelin’s globe-trotting, the DELAG used fixed stub masts and mooring circles at various locations. Footage of Graf is the subject of our silent unedited footage DVD “Graf Zeppelin LZ-127.” (At the Graf’s refueling base at Pernambuco, near Recife, Brazil, the stub mast has been restored.) There was international agreement on the dimensions of the airship’s mooring spindle so that any ship might take to a mast any where,german but the Germans saw the American Wellman mast and stern beam as massive overkill. For their larger ships the DELAG eventually developed their own lighter mobile masts (photo) which used the docking rails for support. When their Santa Cruz mast wire failed during LZ-129’s first South American docking, the ship’s engines had to be used to help push the ship in the hangar. Sadly, this was not the only handling hiccup made by the masters of the rigid airship.


In a hurry to get a propaganda flight underway on schedule the gusty morning of the 26th of March, 1936, with sister Graf awaiting in the sky above, an over the protest of Dr. Eckener, Captain Lehmann ordered the rollout for a difficult downwind takeoff.  The cable parted, the car crew could not hold him and LZ-129’s bow rose fourteen degrees, smashing the lower vertical fin’s aft tip and rudder into the ground.  Recovering after a short free ballooning experience, the ship was brought back and landed safely. The bottom six feet of the lower rudder was cut away, the fin tip faired in and the whole mess was sewn up to permit Hindenburg to depart on a three-day propaganda flight. Scant photos of the damaged surface exist since cameras were quickly rounded up on the ground.  This photo showing the damage came from the National Museum of Naval Aviation.


When the US Navy’s agreement with the DELAG was extended for the new LZ-129, Zeppelin Captain Ernst Lehmann told the first USN liaison reaching Germany, LCDR Scott Peck, that the Germans had no intention of doing a “flying moor” with the LZ-129.  One can only imagine the chaos of crashing dinnerware and sliding passengers if the liner adopted the American’s tail-raising technique. Instead, beginning with his first visit on May 9th 1936, Hindenburg came in just over the trees, dropped his lines, and was walked and winched up to the Wellman mast. (This newspaper photo from the first landing had been retouched to emphasize the mooring cable being winched to the Wellman mast.) This was practical because LZ-129 was the first rigid to have… wheels! The Germans said landing gear was a revolution in ground handling: approaching with the ship a bit heavy made for much easier – and safer – mastings. (There was one account of a modified, likely even-keel “high” landing was attempted during the 1936 season, possibly the 4th visit, at which time the newsreel cameras seem to have lost interest. If true, this was in clear, if windy weather, nothing like an electrically-rich thunderstorm.) Many of the landing cycle footage often passed off as the last one are included in our mostly silent, raw footage DVD collection, “The Hindenburg.”


129-tail-beam-z-2jpgThe Germans refused to allow the ship to be docked using heavy stern beam and spreader gear system, instead only permitting the tail to be pulled with the beam by locomotive regardless of the wind until lined up with the hangar’s docking rails. In this photo the massive fin sits atop Hangar #1’s individual-paver “brick” floor with the disconnected beam nearby. The ship was only docked there twice, facing a different direction each time.


It proved far more practical to simply moor out, servicing the ship for turnaround while on the Wellman mast. The mooring circle’s rails were adapted and a new trolley car built, featuring a 129-trolleyminiature “plumb bob” and “flower pot” copied from the mast. Platforms were lowered from the ship to take up drums of lubrication oil for hand pumping aboard. (more detail is given on the page US Navy and the Hindenburg.)


Unfortunately the nasty weather of May 6th, 1937, lead to the Americans recommending the landing technique the Germans said they would never do. Read  Eugen Bentele’s memoir (“The Story of a Zeppelin Mechanic, My Flights 1931-1938”) in which he recalls wondering “Why don’t we land?”

That night, the so-called “high landing” was not familiar to most involved. (Per the testimony of second watch officer Heinrich Bauer, their 129-track-inlowest altitude was 90 meters—about 295 feet). Likewise ground crew members Bob Buchanan and Frank Ward told interviewers that they were very surprised the Hindenburg came in so high. The ground crew were used to the Zeppelin coming in just over the trees, then dropping the lines for them to grab. However, in what is constantly mis-identified as the “Hindenburg explosion,” this decision to honor the host’s request proved to be a key link in a very complex accident chain.


The last rigid airship’s operations were conducted from mast-equipped facilities – Friedrichshafen,  Löwental and Frankfurt. Improvements to the LZ-130’s covering and electrical bonding insured another fabric fire was impossible, but electrical expert Professor Dickemann and the “Donnerwagen” still made checks of atmospheric electrical activity during evolutions. Improving upon proven ground handling techniques, in early 1939 the Germans were developing an aft windlass which looked to decrease the number of men required for handling.


When WWII began and the last rigid airships were dismantled, handling of non-rigid airships at first seemed frozen at the level of development of the mobile mooring and “stick” masts of old. Scores of men were employed to handle lines and manage cars and tails. This continued postwar; as airships increased in displacement, masts were also enlarged, but the number of ground handlers did not decrease. Finally, in the closing years of the US Navy airship program, winch-equipped tractors – “mechanical mules” – were developed. Reducing the number of troops needed from dozens to only seven, even the largest blimps – the 1.5 mil cu ft ZPG-3W – could be undocked and launched, recovered and docked with less than a dozen men. The type V mobile mast (photo) was the ultimate anchor, height-adjustable and APU equipped. A good sampling of the history of ground handling can be seen in a series of films included in our DVD “Airship Handling.”


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