USS Shenandoah (ZR-1)
ZR-1 "USS Shenandoah" was the first rigid airship that was lifted by the lifting gas helium . It was also the first of three rigid airships built in the United States in the 20th century. It determined the airship scene at the Lakehurst naval air base from 1923 to 1925. As the first large American airship, it was originally intended to be the cornerstone of an American airship industry.
The term Shenandoah comes from the Algonquin language of the Powhatan Indians and means daughter of the stars . From 1920 the abbreviation ZR stood for steerable rigid airships in the US Navy .
Construction and construction
The construction of the airship was based on that of the zeppelins from the First World War . The direct model was in particular the German naval airship LZ 96 "L 49" , which was forced to land on October 20, 1917 after an operation over England on French territory and fell into the hands of the Allies almost undamaged. ZR-1 was designed by the designers Hunsacker and Weyenbacher without German support.
ZR-1 was built on the Lakehurst Naval Base, New Jersey , in Hangar No.1 . The client was the US Navy. The individual parts were manufactured in the Navy aircraft factory in Philadelphia and brought to Lakehurst by rail and truck. The first frame ring from the middle section arrived in late April 1922, was put together and erected and supported from below on April 24th. From there, the framework was quickly completed in both directions. In November it was already 75 percent complete.
The steel cables that tensioned the skeleton rings divided the ship into 20 sections, each ten meters long, in which the gas cells were located. On November 23, 1922, the first gas cell was inserted and inflated with air.
At the beginning of February the framework was almost finished and the covering, which was made of high quality cotton fabric , began to be put on. The lengths of fabric were tied tightly and then coated with several layers of lacquer . The material shrank and was pressed firmly against the skeleton. The separation points were covered with sealing strips. This created a smooth outer shell. Aluminum powder was added to the final outer coat to create a smooth, weatherproof surface. It should reflect the sunlight in order to limit the heating of the lifting gas.
Equipping the ship began at this time. Installations such as cables, pipes, fittings , ballast water tanks , etc. were installed along the keel staircase. The command (or guide) and engine pods were also completed and attached under the fuselage. In contrast to the command gondolas of later airships, the command gondola was not attached directly to the fuselage or integrated into the fuselage, but rather hung under the fuselage with beams and cables. The rear machine gondola and the command gondola were equipped with handrails for the ground crew.
The engine arrangement consisted of one engine behind the command gondola, two engines relatively close together under the fuselage, two further engines - also arranged in parallel, but offset slightly upwards - under the fuselage and a stern engine. The engine, which was located directly behind the command gondola in its own gondola, was removed during repair work in May 1924. Instead, the driver's gondola was extended to include a radio cabin. Ballast water extraction systems were installed above the motor nacelles . Their air resistance caused a noticeable reduction in top speed. In order to keep the helium losses low, the number of pressure relief valves was limited to 10 pieces. However, the 20 gas cells were connected to one another.
In June 1923 only the engines were missing. After various attempts in the hangar, the ship was ready for gas filling.
The airship was originally designed for hydrogen as a lifting gas, but doubts arose in 1921 after the disaster of the airship Roma , which was acquired from Italy , and the Bureau of Aeronautics (BuAer) recommended filling ZR-1 with the noble gas helium, via which to this At that time only the USA had significant quantities, which was extremely expensive compared to hydrogen. In 1921, for example, a cubic meter of helium cost more than $ 4, compared to 7 to 10 cents for hydrogen. In total, a single filling of the airship cost $ 240,000, which is roughly the equivalent of $ 3.6 million today.
Trial and Baptism
On September 4, 1923, the airship was pulled out of the hangar for the first time. For this demanding task, soldiers and civilians employed on the base were recruited, a total of 420 men. Some simple mechanical devices assisted the struggling ground crew, but major improvements were not to be introduced for years to come. The entire process was watched by around 15,000 spectators, dignitaries and journalists. At 5:20 p.m., the ZR-1 took off on its maiden voyage with 29 people on board .
Further test drives followed. During these first trips, the German airship captain Heinen was on board as a consultant and the designer Weyenbacher was on board, and they were also allowed to be part of the team on later trips. This included, for example, a trip to Philadelphia and Washington on September 11th and a 35-hour trip via Pittsburgh , Columbus and Dayton to St. Louis from October 2nd to 4th, to land an hour and a half at the International Pulitzer Air Races , the trip was then continued via Peoria and Chicago .
On October 10, 1923, the ship was handed over to the operator, the US Navy . On that day, the ZR-1 was officially named "Shenandoah". Godmother was Mrs. Denby, the wife of the Secretary of the Navy Edwin Denby. Admiral Moffett was present along with other officials . The baptism was followed by a four-hour drive with the baptized guests and some reporters. Two days later the airship was added to the list of US Navy ships. Lakehurst became a base.
business
In the months after its christening and the first weeks of 1924, the USS Shenandoah made several voyages, including over the eastern United States, to train the crew and introduce the nation's first rigid airship to the United States October, 16 hours over the Virginia Valley for Navy Day . On November 20th, a trip was made to Boston , New England .
On November 5 and 16, after several previous unsuccessful attempts, the ship moored for the first time at the anchor mast in Lakehurst. It was anchored to the mast twice more in December and twice in January until extensive attempts at mast use began. It was the first experience of American airshipmen with this technology. The conditions for an Arctic voyage should be practiced. This was announced by Admiral Moffet at a press conference after the baptism. The New York Times reported that the new, then untested, airship would be sent on a voyage across the capitals of the United States and the rest of the world, as well as to both poles . However, this announcement was far from reality. The crew only gained experience in handling the ship through handling it. The US Navy had a large airship base, but in 1924 the use of anchor masts was still being used. These attempts had started with a view to the Arctic voyage, since anchor masts would then be the only available bases for the airship. Planning for the polar voyage was interrupted by President Coolidge in mid-February. Nevertheless, Admiral Moffet and the naval command, supported by the airship propaganda and general public enthusiasm, still expected too much from “their” large airship within too short a time.
Storm damage to the anchor mast
Starting on January 12th, all further voyages of the ship were carried out from the anchor mast. With the intention of testing the ship's behavior at the anchor mast even in bad weather, Commander McCrary had the ZR-1 moored for a week, manned by only one hull crew, so that the ship could be raised immediately if the conditions required it .
On January 14, the weather bureau issued a storm warning for January 16 and 17. Since the behavior of the ship should be tested at wind speeds of up to around 95 km / h , it was decided to leave it on the anchor mast. The gusts reached speeds of up to 100 km / h in the evening. The ship rolled back and forth on the mast. McCrary had left the ship briefly, but was called back because Captain Heinen, who was also on board, wanted to detach the ship from the mast and "ride" the storm in the air. The engines had already been warmed up. At 18:44, a gust of 125 km / h hit the ship on starboard, destroyed the upper tail fin and caused the ship to roll precariously. The twisting of the ship resulted in an overload of the structure at the nose. She broke and released the ship, leaving the nose cap on the anchor mast. The damage caused the ship's two forward gas cells to empty. The crew of 22 reacted immediately, 1900 kg (4200 pounds) of water ballast were immediately dropped, and the crew was sent to the stern for trimming . The engine operators on duty were signaled to start the engines, which were started quickly and allowed a certain degree of control over the ship again after only 4 minutes. After further ballast was dropped and the ship was trimmed, it was allowed to sail before the storm. The radio system had also been damaged. It was not until 9:00 p.m., more than two hours after the "start" of the 20th journey from ZR-1, that you could report to the base.
The wind subsided over the next few hours. However, control was difficult due to the damage to the tail unit. At 3:30 the next morning, the ship was brought back to Lakehurst by 400 ground crews in the airship hangar. The worst storm in 50 years had also damaged other parts of the country. There was a lot of praise from everyone involved and admiration from the public for the team's quick reaction, but they were also angry about the incident. The subsequent investigation did not reveal any serious wrong decisions, but Lieutenant Commander Zachary Lansdowne , one of the “best” airship supporters in the Navy, replaced McCrary on February 11, 1924 as commander. The anchorage on the mast was redesigned so that it would release the ship in the event of overload, so as not to risk damaging the bow again. Despite these experiences, the same mishap with a similar course was to happen to the English rigid airship R33 a year later on April 16, 1925 .
After the repair
The repairs took four months and cost $ 78,000, including an overhaul. Among other things, the engine behind the driver's gondola was removed and a separate radio cabin was added after the radio problems. Then the "Shenandoah" was put back into active service in May 1924. On August 8, the airship carried out the first of many berthing maneuvers on the specially converted original oil tanker USS Patoka . Then she was involved in a maneuver with the fleet, which she had to stop after 40 hours because of an engine failure.
In October 1924, ZR-1 took a tour of the west coast of the USA. This "transcontinental voyage", which was carried out instead of a planned maneuver near Hawaii under Commander Lansdowne, was intended to show the critics the efficiency of the ship and present it to the Americans. The 18½ day trip began on October 7th and led from Lakehurst via Washington and Atlanta to Fort Worth (Dallas). Then the ship followed the Texas and Pacific Railroad to overcome the Rocky Mountains . Several critical situations arose in the narrow passes and valleys due to the difficult winds.
On arrival at North Island Naval Air Station San Diego , the stern hit the ground, not least due to the inexperienced landing crew. The subsequent repair was carried out on the anchor mast at a height of 45 meters and took five days. From October 16-18, the ZR-1 drove 2200 km along the west coast to Camp Lewis near Tacoma . The following day she made her way back along the coast to San Diego, where she arrived on October 21.
Overcoming the mountains in California and Arizona on the way back to Lakehurst was another challenge. The required height could partly only be achieved by dropping ballast, partly also fuel. The return journey from Fort Worth then took us via Hot Springs / Arkansas , the Mississippi River , the Ohio River , Indiana , Ohio and Columbus , heading east towards the Atlantic .
After returning to the Lakehurst base on the night of October 25, the airship was temporarily decommissioned in order to be able to use the helium that was scarce at the time for the airship ZR-3 "USS Los Angeles" , which had just arrived from Germany and which is now in Hall next to the "Shenandoah" was.
Only in July 1925, when the "Los Angeles" was in the airship hangar for an overhaul, the "Shenandoah" was put back into operation. For this purpose, the ZR-3 had to give back the majority of its helium filling, which at that time represented practically the entire world reserve. This summer, trips to check the engines and radio technology, as well as some exercises to test various military tactics with the fleet of the US Navy and other parts of the Navy Armed Forces were carried out. This remained the only real use of the airship.
The end
The "Shenandoah" crashed on September 3, 1925 in severe turbulence (other sources speak of a storm) over southern Ohio near Ava ( Noble County ). This trip was supposed to be the first leg of a commercial flight to the American Midwest. It began on September 2nd and, on the occasion of the national holiday, was to lead over a total of 40 cities within six days that wanted the airship to appear on the occasion. Commander Lansdowne had raised concerns about the known unstable weather conditions in the Midwest.
On the morning of the following day, vertical winds tore the airship up and down several times, so that the crew lost control of the airship. Within a very short time it rose above its impact height to up to 1,300 meters. Then it sank to 200 meters in just three minutes, only to rise again to 1200 meters shortly afterwards. These loads were too high for the ship. After the middle gas cells were damaged and drained and the airship was hit by further gusts, it broke in the air. The command gondola came loose and fell. Eight airmen died in it, including the commander. Three crew members fell to their deaths from the break. The tip of the bow floated away like a balloon and landed about 20 kilometers south. Seven people had survived in it, including Lieutenant Charles E. Rosendahl . The tail section broke again. Two motor gondolas fell off, killing three other men. The two remaining parts of the airship body landed relatively gently just a few hundred meters from the site of the accident.
At the crash site ( ) near US Route 21 (now Interstate 77 ), a memorial was erected for the airship and the 14 dead of the 43-strong crew.
In retrospect it was also pointed out that the model for the "Shenandoah", the war zeppelin LZ 96 / L 46, was not just a medium-sized airship, as originally assumed, but a high-altitude bomber specially designed for lightweight construction . The German model was supposed to drive higher than all Allied fighters in World War I. The framework was therefore not designed for the loads that occur during heavy maneuvering .
The knowledge gained from the construction and operation of ZR-1 flowed into the later large airships of the USA, the USS Akron and USS Macon . These included:
- changed proportions of the trunk for more stability
- an aerodynamic command gondola that was attached directly to the ship
- Relocation of the motors inside to achieve easier access and a reduction in air resistance
The accident also showed that the weather forecast needed to be improved.
The USS Shenandoah had made a total of 59 voyages and covered 45,000 km (28,000 mi) in 740 hours.
Technical specifications
- Length: about 207 m (680 ft)
- Hull diameter: about 24 m (79 ft)
- Volume : approximately 59,900 cubic meters (2,115,000 cubic feet)
- Weight: 38 t
- Payload: 22 t
- Drive: six water-cooled Packard engines with 220 kW (300 PS) each (one engine was removed later)
- Speed: about 110 km / h (60 kn)
- Range: about 4455 km (2770 nautical miles)
- Crew: about 40 men (officers and men)
- Price: $ 1.5 million
See also
literature
- Peter Kleinheins: The big zeppelins. VDI-Verlag, Düsseldorf 1985, ISBN 3-18-400687-5 .
- Lewis H. Gray: Ill wind. The naval airship Shenandoah in Noble County, Ohio. Gateway Press, Baltimore 1989.
- Aaron J. Keirns: Ohio's airship disaster. The story of the crash of the USS Shenandoah . Little River Publishing, Howard Oh 2000, ISBN 0-9647800-2-X .
- Thomas S Hook: Shenandoah saga. A narrative of the US Navy's pioneering large rigid airships . Air Show, Annapolis 1973.
Web links
- USS Shenandoah on the pages of the US Naval Historical Center ( Memento from October 13, 2014 in the Internet Archive )
- Lakehurst Historical Society (main source for articles) ( February 18, 2014 memento in Internet Archive )
- noblecountyohio.com/shenandoah.html (English)
