Basic hot-air balloons have one distinct problem in that they float wherever the wind takes them and except for altitude, they cannot be controlled. Numerous Victorian inventors addressed this problem and they tried several ways of steering balloons. Although the steering devices were never very effective for the typical spherical hot-air balloon, a new means of air travel, the airship or dirigible, eventually resulted from these efforts. For a short time during this period, a transitional type of craft that was somewhere in between a balloon and an airship existed.
One of the most promising schemes for steering balloons was to use an engine with a propeller to guide it through the air. The first attempts at this directional control employed steam engines and proved to be extremely cumbersome and dangerous. Additionally, the spherical hot-air balloon had too much drag and lacked sufficient lift, stability and directionality, making it an ineffective configuration for this technique. Efforts to control balloons gradually brought about new elongated designs that could move through the air more easily, were more stabile, and had directional attributes.
In 1852, a French engineer named Henri Gifford successfully added a three-horsepower steam powered propeller to guide and propel an elongated balloon. Gifford's flight marked the first time that a balloon was successfully steered.
Charles Renard and A. C. Krebs built the first successful craft that could more-or-less be considered an airship. Named the La France, it flew 5 miles, or 8 kilometers, on its voyage of August 9, 1884.
In 1898, experiments with new gasoline engines for steering balloons by the Brazilian Alberto Santos-Dumont showed promise. Alberto Santos-Dumont equipped a cigar-shaped craft with a gasoline engine driven propeller allowing him to steer and propel his ship. On October 19, 1901, he successfully navigated a seven-mile (11km) course above Paris winning the Henri Duetsch prize of 125,000 francs for his feat.
David Schwarz, an Austrian engineer, built the first rigid airship. It crashed on its maiden flight of November 3, 1897. Although Schwarz's craft crashed, it was a major influence on Count Ferdinand von Zeppelin's later work with airships.
Airships not only have several advantages over balloons, but over all other forms of air transportation as well. One big advantage that airships have is that, once underway, they are extremely energy efficient. Not only are they capable of staying aloft and hovering in the same spot indefinitely, but also they are relatively stable, vibration-free and quiet. Because of these attributes, they remain indispensable for aerial photography, filming motion pictures and as aerial research facilities.
Types of Airships
As airships evolved, several distinct types appeared
RIGID airships have an inner framework supporting a gas-tight envelope or skin. The rigid framework, usually a light metal such as aluminum, holds the ship together and supports the form. All airships made by Luftschiffbau Zeppelin GmbH and two dirigibles made by the Goodyear-Zeppelin Company USA, the US Navy's Akron and Macon, were rigid airships. Generally, rigid airships must be longer than 360feet / 120meters or else the weight to volume ratio will make them too inefficient. In other words, a small rigid airship would have too much framework in proportion to the amount of lifting gas that it could hold making it too heavy to fly. The rigid style of dirigible was the preferred design in Germany and most of the important historical events occurred in these ships.
SEMI-RIGID dirigibles have a rigid keel that supports a pressurized envelope. The design may call for the keel to be attached directly to the envelope or to be hung underneath it. The parts of the vessel such as the gondola and engines are attached to the rigid keel. The most famous semi-rigid airship was the Italian Norge, which flew over the North Pole in 1926.
NON-RIGID airships, now commonly known as blimps, are the most common type in use today. The non-rigid airship has no frame and the envelope holds its shape due to the pressurized lifting gas, usually helium, inside. To compensate for changes in gas pressure, non-rigid airships are equipped with internal air compartments called ballonets that can be inflated or deflated.
BLIMP There are several different accounts about the origin of the word blimp. The story that seems to be preferred by airship experts is that Lieutenant A. D. Cunningham of Great Britain's Royal Naval Air Service originally coined the name. Legend has it that while conducting an inspection, he flipped the envelope of Airship SS-12 with his thumb and the tightly stretched fabric made a strange noise. Imitating the sound that came from the airship, he cried out "Blimp!" and the name stuck.
ENVELOPE is the jargon term for the gas-tight outer skin, or covering, of airships.
GONDOLA OR CONTROL CAR are the names for the structure that houses the pilot, crew and passengers. In some airships, this facility is inside the envelope.
NACELLES are the housings that contain the engines. In some airships, the engines were inside the envelope and the propellers were driven by belts.
The most prominent builder of rigid airships was Count Ferdinand von Zeppelin, a retired German Army officer. Zeppelin developed what can be considered the first truly successful airship and founded a company under his own name to build them. Because the Zeppelin Company was the most famous builder of airships, the name Zeppelin became a generic term for all airships. During the 1930s, Goodyear's lighter-than-air division partnered with Zeppelin, becoming the Goodyear-Zeppelin Company, adding to this language shift. The fact that Goodyear specialized in non-rigid airship designs confused the matter further. As World War II approached, the Zeppelin name was dropped from the Goodyear Aeronautics Division out of political correctness. The generalization of the Zeppelin trade name was similar to the legendary case of the Kleenex brand name becoming the common generic term for facial tissue. Today, airship, dirigible and zeppelin are all synonymous terms for three-dimensionally controllable lighter-than-air craft.
Count Ferdinand von Zeppelin served as an attaché in Washington during the American Civil War and he observed first-hand the usefulness of balloons in warfare. After returning to Germany and retiring from the German Army, Zeppelin, an excellent designer, began working on his new airships in 1890. In 1900, Zeppelin's first airship, the LZ-1, was tested. It flew at a speed of about 18 miles per hour, or 29 kph. It made three successful voyages, but it was abandoned because of a lack of money. In 1905, Zeppelin obtained new financial support from manufacturers and the German government. He then built an improved model the LZ-2, which crashed in a storm after its successful maiden voyage. Because of the problems with air currents that the early airship builders experienced, Count Ferdinand von Zeppelin was one of the first designers to use a wind tunnel as a design aid. He built two additional models that were complete successes - thereby securing additional government support. In 1908, Zeppelin founded the Zeppelin Airship Company, actually called Luftschiffbau Zeppelin. By 1910, the Zeppelin Company was operating the world's first commercial air transport service. Eventually, Zeppelins would be able to cruise at speeds around 80 miles per hour, or 128.8 kph, and 119 of them were built between 1900 and 1938.
Goodyear Tire and Rubber Company
The Goodyear Tire and Rubber Company, founded in 1898, became active in the aviation industry in 1910 by selling rubber-impregnated fabric products and resins to aircraft manufacturers. Taking a more direct approach, Goodyear's first balloon was completed in 1912 and the company continued building and flying balloons in competitions thereafter.
In 1916, Goodyear bought space for an aeronautic division near Akron, Ohio. Airship production began at Goodyear in 1917 as America's entry into World War I loomed. Eventually, by the time that Goodyear quit mass-producing airships, the company had manufactured about 350 of them - more than any other company in the world.
Goodyear began operating its own airships in 1919. However, the public relations blimp program did not begin until 1925 when the company built its first helium-filled airship and named it the Pilgrim. Since then, Goodyear has kept a public relations airship giving many people their only glimpse of one. The company now operates six airships worldwide and three of them operate in the United States.
Goodyear Aeronautics developed several interesting military aircraft concepts in the 1950s and early 1960s. Some of these include the GA-22 Duck amphibian airplanes, the GA-33 Inflatoplane and Gizmo, a one-man helicopter. They also built the enormous ZPW-3W airship for the United States Navy, the largest non-rigid airship ever built. Unfortunately, the ZPW-3W was destroyed by strong winds in February of 1962, shortly before the Navy retired the remainder of its airships.
World War I
GREAT BRITAIN experimented with both rigid and non-rigid airships during World War I to match the threat of the fleet of German dirigibles. In total, British forces acquired more than 200 airships to use in various military applications making England the biggest airship force of the war. The designs of two British dirigibles, the R-33 and R-34 were copies of the design of a German Zeppelin that had been confiscated during the war. The R-34 made the first successful transatlantic flight in July of 1919.
Britain built two more dirigibles, the R-100 and the R-101, but the R-101 crashed in France killing 47 people. Because of this incident, the British lost interest in airships and the R-100 was dismantled.
GERMANY used airships during World War I made by the Zeppelin Company and the Schutte-Lanz Company. German airships conducted more than 50 bombing raids over London and Paris as well as other reconnaissance and freight missions. The excellent designs of the German airships gave Germany air supremacy in the early days of the war. There were several design differences between Zeppelin and Schutte-Lanz airships; the most important difference was that the Schutte-Lanz airships had wooden frames while the Zeppelins had metal frames. When allied aircraft gained the ability to reach the altitude that the dirigibles cruised at, the slow ships became easy targets and they fell into disuse for the remainder of the war.
RUSSIA purchased two airships from France in 1909. Russia began an airship building program in 1931 and there was a commercial airship service operating inside the Russian interior by 1937.
UNITED STATES citizens were interested in airships and Thomas Baldwin built one of the first American dirigibles in 1904. There were several US military airships in operation during World War I, but because the United States did not enter World War I until 1917; there was little notable use of American airships during the war.
Airships Between The World Wars
Germany was restricted from building airships for a while after World War I by the Allies. After the restrictions were lifted in 1925, Germany continued making and improving airships. As part of the reparations to the Allies, Germany had to turn over twelve dirigibles to the allied nations. Since Germany only had eleven airships remaining at the end of the war, another craft had to be built. Designated the LZ-126 in Germany, the Luftschiffbau Zeppelin GmbH craft was transferred to the United States Navy and renamed the Los Angeles. It was the most successful rigid US Navy airship.
The successes of the Los Angeles persuaded the Navy to acquire two more rigid-airships. The Goodyear-Zeppelin Company, a partnership between the Goodyear Tire and Rubber Company and Luftschiffbau Zeppelin GmbH, manufactured them. The helium-filled Akron, built in 1933, served as an aerial aircraft carrier capable of carrying five pursuit airplanes inside its hull. The Akron was 785 feet long and crashed in a violent storm off the coast of New Jersey in 1933 creating 73 fatalities. A sister ship of the Akron, the Macon, had the same specifications and went into service in 1933. It also had a tragic end when it crashed in the Pacific Ocean in 1935 with two fatalities. The Macon was the last rigid-type airship commissioned by any branch of the United States military.
The United States Navy also experimented with helium as a lifting gas for dirigibles in the 1920s and in 1923 built the world's first rigid helium airship the Shenandoah. The design was successful and it made many flights, but it crashed in a strong storm in Ohio in 1925.
US Army Air Service
The United States Army Air Service expanded its lighter-than-air division after Wold War I and continued to use various types of balloons for different purposes as well. The Army Air Service experimented with both non-rigid and semi-rigid airships during this time.
As a part of this experimentation, the Army Air Service bought the Italian semi-rigid airship, the Roma, in 1920 for $165,000. After the Roma went into service with the Army, they had many problems with its Italian-made Ansaldo engines. The Air Service decided to replace the Ansaldo engines with Liberty engines, and the first flight of the Roma with Liberty engines was from Langley Field, Virginia on 21 February 1922. The Roma had forty-five people onboard including seven civilian technicians from McCook Field.
During the flight, the nose structure of the Roma collapsed causing the elevator controls to jamb. Unable to navigate, the Roma lost altitude and settled on some high-tension power lines near the Army Supply Base at Norfolk, Virginia. Upon contacting the power lines, the Roma’s hydrogen gas exploded in an enormous fireball leaving only eleven survivors.
The Army Air Service continued its lighter-than-air division until June of 1937, when tight funding forced Major General Oscar Westover to eliminate the program. In July, the United States Navy accepted the remainder of the Army’s lighter-than-air fleet. The Navy was the only American military service that operated airships after 1937.
What's in a Name?
Air Service, Air Corps, Signal Corps and Signal Service
The first branch of the US military to have an air division was the US Army, which founded an air division during the American Civil War in 1864. An official replacement for the civilian Balloon Corps of 1861, the division was a part of the Signal Corps or Signal Service, names that were used interchangeably from 1864 to 1891. The first time that an actual aeronautical division was founded was in 1907 and it was also part of the US Army Signal Corps. The aeronautical division was created as the Army worked to develop and acquire its first heavier-than-air flying machine from the Wright Brothers, which it completed in 1909.
The aeronautical division was upgraded in 1914 and again in May 1918, when the War Department made the aeronautical division a separate branch of the US Army. This branch was called the US Army Air Service and in 1926, it was renamed the US Army Air Corps. At this point, the Air Corps became a branch of the Army equal to the Infantry, Cavalry or Artillery, for example. In June 1941, the Air Corps had another metamorphosis when it was merged with other army aviation elements and made equal to the Army Ground Forces and Army Service Forces. It was now renamed the Army Air Forces. This organization continued in operation until after World War II, when it was separated into an entirely new branch of the US military - like the Army, Coast Guard or Navy - named the United States Air Force on 18 September 1947.
Although the US Army Air Corps evolved into a separate branch of the US military, the Army continued to operate its own aircraft, as it does today. This air capability traces its origins to 1942. During World War II, the Army Air Forces became increasingly engaged in combat and strategic missions, sometimes not having sufficient resources to assist artillery forces with spotting targets. Aerial targeting was crucial for successful artillery missions, however, and the artillery corps began to use their own small airplanes for this purpose. Known as organic aerial support, the results were successful and a separate aviation branch of the army was created to fulfill this need. The use of organic support aviation continues today in all branches of the US military.
The Graf Zeppelin
The Graf Zeppelin, completed in 1928, was one of the one of the most successful airships of all time. The Graf Zeppelin was an enormous airship measuring 800 feet long and 100 feet wide, or 243.8 meters by 30.5 meters. Its top speed was more than 70 miles per hour, or 112 kph. It could carry 50 passengers. It circumnavigated the world in 1929. Departing from Lakehurst, New Jersey, it returned in 21-1/3 days. After that, it was used for commercial airline service between Germany and South America until 1937.
The giant and luxurious Hindenburg, the largest airship ever built at 803 feet long and 135 feet wide, or 244.7 meters by 41.2 meters, was completed in 1936. The Hindenburg made 54 successful flights, 36 of which were transatlantic crossings before it flamed spectacularly out of existence while docking at Lakehurst, New Jersey in 1937.
The arrival of the Hindenburg was a major media event so newspaper photographers and radio news reporters anxiously awaited its arrival. The explosion of the greatest Zeppelin was recorded on film and the photograph appeared on the front page of nearly every newspaper in the world. The live radio broadcast, one of the most famous of all time, narrated the event in vivid detail. The reporter clearly relayed the vexing events that he was witnessing such as the flaming human bodies plummeting from the hovering fireball which was glowing like the sun and giving off a similar amount of heat. The publicity of the disaster seared the incident indelibly into the world's collective mind's eye, creating an insurmountable public relations problem for the company. Because of this tragedy, passenger transport by airship ended along with the airship's halcyon age. The Hindenburg’s demise was attributed to the explosive hydrogen gas used for buoyancy at the time, but alleged forensic scientific testing later revealed that the true source of the Hindenburg’s problem may have been a powdered aluminum coating on the envelope.
It was unfortunate for the Luftschiffbau Zeppelin company that the Hindenburg incident received so much publicity. Until the Hindenburg's fateful arrival in New Jersey, zeppelins had enjoyed an excellent safety record and no commercial passengers had been killed. Zeppelin airships had made hundreds of successful flights safely carrying thousands of passengers, a particularly notable achievement during the early days of aviation. They were actually far safer than any other mode of air transportation in that period. Although the Hindenburg exploded, there were only 35 fatalities out of the 97 people onboard. The zeppelins were the only means of air transportation in that day that could carry that many people successfully and were the earliest form of transatlantic commercial air service. The Luftschiffbau Zeppelin model LZ-130 was completed in 1938, but never saw much use.
World War II
Dirigible use continued after 1937, but for the most part, only helium-filled military airships remained in use. Helium was difficult to obtain outside of the United States and few other countries retained their dirigible programs.
By the time that World War II began, the United States Navy was the only military force in the world that had an airship division. Likewise, the only company in the world that maintained an airship program was the Goodyear Tire and Rubber Company. Worldwide, airship designers quit using the rigid design because this configuration was responsible for many of the other problems that airships had experienced. Since airships are enormous, strong winds can cause major structural damage and the rigid type cannot be made strong enough to withstand powerful gusts. The non-rigid type of airship can deform in strong gusts and then return to its original shape as the force subsides.
The United States Navy operated airships for a variety of purposes during World War II. They were primary used as escorts for convoys. The blimps could easily spot submarines and travel with the slow-moving ships. No ships were lost through submarine attack while being escorted by a US Navy blimp. Although the airships were very slow compared to World War II airplanes, none were lost in aerial combat. Blimps were also used to patrol American borders and to lookout for aerial attacks upon the mainland.
After World War II
The United States Navy continued to use airships for a variety of applications until 1962 when they retired the remaining dirigible fleet, some of which were put into storage. The airships had been very useful to the Navy but newer technology made them obsolete.
In the 1940s and 1950s, the Navy used airships for shore patrol to protect merchant ships. They were also used as early warning radar stations in the early days of the Cold War. Some large radar airships could stay aloft almost indefinitely. One of the ships holds the World's record for flight endurance of eleven days. In March of 1957, the Navy's ZPG-2 flew from Weymouth, Massachusetts to Europe and on to Africa ending at Key West, Florida without refueling or landing.
The Goodyear public relations blimps continued to travel through the skies up to the present time. During much of this period, they were the only airships flying. The Zeppelin Company continued in business, but, until recently, made its last airship in 1936. In the 1990s, the Zeppelin Company resumed manufacturing airships using more modern materials and helium as the lifting gas. The result is the new Zeppelin NT airship, NT standing for new technology. The Zeppelin NT first flew in 1997 and was certified in 2001. It is now available for public passenger service in Germany.
Perhaps the greatest limitation of airships is that they require many persons in a support ground crew making them expensive to launch and dock. The relatively small Goodyear blimps each require a ground crew of fifteen. Perhaps someday, airships will become more prevalent if improved technology can reduce the need for support personnel to operate them.