20 August 1919: The first airship built after World War I, Bodensee, LZ 120, made its first flight at Friedrichshafen, Germany, with Captain Bernard Lau in command. LZ 120 was built for Deutsche Luftschiffahrts-Aktiengesellschaft, DELAG, (German Airship Travel Corporation) especially to carry a small complement of passengers. It was hoped that this would generate favorable publicity and help to restart intercity travel by air.
Bodensee was the first fully-streamlined airship. Its teardrop shape was developed by engineer Paul Jaray and had no cylindrical sections. The shape had been tested with scale models in a wind tunnel. LZ 120 was the first airship to have the gondola was attached directly to the bottom of the envelope, decreasing aerodynamic drag.
LZ 120 was a rigid airship, or dirigible, with a metal skeleton structure covered with a cotton fabric envelope. Twelve hydrogen-filled buoyancy tanks were contained within the structure. A crew of 12 operated the airship and it could carry 20 passengers.
LZ 120 was 396.33 feet (120.8 meters) in length, with a diameter of 61.38 feet (18.71 meters). The airship had a volume of approximately 20,000 cubic meters (706,000 cubic feet). The airship had an empty weight of 13,646 kilograms (36,698 pounds) and a gross weight of 23,239 kilograms (51,233 pounds).
LZ 120 was powered by four water-cooled, normally-aspirated, 23.093 liter (1,409.2 cubic inches) Maybach Motorenbau GmbH Mb IVa single overhead cam (SOHC) vertical inline six-cylinder engines with a compression ratio of 6.08:1 and four valves per cylinder. The Mb IVa produced 302 horsepower at 1,700 r.p.m., but was derated to 245 horsepower. Two engines were mounted in the aft centerline engine car and drove a two-bladed propeller with a diameter of 5.2 meters (17.1 feet) through a reversible gear train. Each of the other engines were mounted near the center of the airship, outboard. They each turned a two-bladed propeller with a diameter of 3.2 meters (10.5 feet), which were also reversible.
LZ 120 had a maximum speed of 82 miles per hour (132 kilometers per hour).
After two test flights under Captain Lau, Bodensee entered scheduled passenger service on 24 August 1919 under the command of Dr. Hugo Eckener. It flew from Friedrichshafen to the Oberwiesenfeld at Munich, then on to Berlin-Staaken.
In 1921, Bodensee was turned over to Italy as war reparations. It was renamed Esperia and continued in operation until 1928.
12 August 1908: Test flights begin for Signal Corps Dirigible No. 1 at Fort Myers, Virginia, with Thomas Scott Baldwin as pilot and Glenn Hammond Curtiss as flight engineer.
On 1 August 1907, Brigadier General James Allen, Chief Signal Officer, United States Army, issued a directive establishing the Aeronautical Division within the Signal Corps. Captain Charles Chandler was the officer in charge. Specifications were published in Signal Corps Bulletin No. 5, soliciting bids for both lighter- and heavier-than air vehicles. There were 41 responses. Plans were submitted and a board of officers selected plans for those that seemed most practical.
The lighter-than-air craft was required to be a self-propelled dirigible (a “directable” balloon) able carry two persons and to be able to travel at 20 miles per hour (32.2 kilometers per hour). Thomas Scott Baldwin’s proposal was selected. (The Wright brothers’ Military Flyer was selected as the heavier-than-air winner on 2 August 1909, and designated Signal Corps Airplane No. 1.)
On 3 August 1908, Baldwin No. 8 was presented to the Army for trials. Although the the Baldwin No. 8 reached an average speed of just 19.61 miles per hour (31.56 kilometers per hour). It demonstrated the required endurance of two hours, averaging 14 miles per hour (22.5 kilometers per hour). Although the airship’s speed was short of the requirement, on 5 August, the Army purchased it from Baldwin for $5,737.59. The airship was designated Signal Corps Dirigible No. 1.
Contemporary sources give the airship’s dimensions as being 96 feet (29.26 meters) long with a maximum diameter of 19 feet, 6 inches (5.94 meters). The envelope was made of two layers of silk fabric separated by a layer of vulcanized rubber, and supported by 30 wooden frames. Buoyancy was provided by hydrogen gas. The envelope’s volume was approximately 20,000 cubic feet (566 cubic meters).
An open girder beam gondola (or “car”) built of spruce was suspended beneath the balloon. The gondola was 66 feet (20.12 meters) long with a 2½ feet × 2½ feet (0.76 × 0.76 meters) cross section. A water-cooled Curtiss-built inline four-cylinder gasoline engine was mounted at the front end of the gondola. The engine produced 20 horsepower and drove the tractor propeller through a steel drive shaft at 450 r.p.m. The two-bladed spruce propeller had a diameter of 10 feet, 8 inches (3.25 meters) and pitch of 11 feet (3.35 meters).
A two-plane “box-kite” canard elevator unit behind the engine provided control for pitch. The pilot was located behind the control surfaces. Another crew member was at the rear of the gondola, followed by a fixed cruciform stabilizer unit.
The dirigible had a lifting capacity of 1,350 pounds (612.4 kilograms). The payload was 500 pounds (226.8 kilograms).
The U.S. Army’s first aviators, Lieutenants Benjamin D. Fulois, Thomas Etholen Selfridge and Frank P. Lahm were taught to fly the airship. Lahm and Fulois made the first flight of an all-Army crew on 26 August.
Signal Corps Dirigible No. 1 was assigned to the Signal Corps Post at Fort Omaha, Nebraska, where the Army had a balloon factory. It was operated there until 1912. The airships envelope needed to be replaced, and unwilling to spend money for that, the airship was sold.
9 August 1884: At the parade grounds at Chalais-Meudon, a town on the banks of the Seine near Paris, France, engineers Charles Renard and Arthur Constantin Krebs made the first controllable free flight when they piloted their airship, La France, over an approximately 4¾ mile (7.6 kilometers) course and returned to their starting point. The airship completed the circuit in 20 minutes at an average speed of 15.75 feet per second (10.74 miles per hour, or 17.28 kilometers per hour).
Charles Renard later said,
“As soon as we had reached the top of the wooden plateaus which surrounded the valley of Chalais we started the screw, and had the satisfaction off seeing the balloon immediately obey it, and readily follow ever turn of the rudder. We felt we were absolutely masters of our own movements, and that we could traverse the atmosphere in any direction as easily as a steam launch could make its evolutions on a calm lake. After having accomplished our purpose we turned our head toward the point of departure, and we soon saw it approaching us. The walls of the park of Chalais were passed anew, and our landing appeared at our feet about 1,00 feet below the car. The screw was then slowed down, and at a pull of the safety valve started the descent, during which, by means of the propeller and rudder, the balloon was maintained directly over the point where our assistants awaited us. Everything occurred according to our plan, and the car was soon resting quietly upon the lawn from which we had started.”
—The Practical Engineer, Volume 9, Number 371, Friday, 6 April 1894, Page 266, at Column 1
From 9 August 1884 to 23 September 1885, La France made seven flights and was able to return to its starting point five times. On its final flight, it reached an average speed of 21.33 feet per second (14.54 miles per hour, or 23.40 kilometers per hour).
La France was a powered, steerable, gas balloon, approximately 167 feet long (50.9 meters) and 27½ feet (8.4 meters) in diameter. Buoyancy was provided by 65,000 cubic feet (1,841 cubic meters) of hydrogen.
Under the balloon envelope hung a 108 foot (32.9 meter) long gondola made of bamboo and covered with silk. This was where the airmen and any passengers, the 8½ horsepower (6.25 kilowatts) electric motor and a chromium chloride storage battery were placed. The motor weighed 220.5 pounds (100 kilograms), and the battery, 580 pounds (263 kilograms.)
At the forward end of the gondola was a four-bladed wooden propeller with a 23-foot (7.0 meters) diameter and 28-foot (2.4 meters) pitch, providing thrust to drive the airship. The propeller was driven by a 49 foot (14.9 meters) drive shaft. On the 9 August flight, the propeller turned 42 r.p.m. On later flights, this was increased to a maximum 57 r.p.m.
La France was controlled by a rudder and elevator. A sliding weight allowed for changes in the center of gravity.
La France was designed and built by Captain Paul Renard, Captain Charles Renard and Captain Arthur Constantin Krebs, all officers of the French Armée de Terre Corps du Génie (Corps of Engineers) at the central military aeronautics establishment at Chalais-Meudon.
Charles Renard was born at Damblain, Viosges, France, 23 November 1847. In 1873, he had developed an unmanned glider which was controlled by a pendulum device linked to its control surfaces. The glider was flown from a tower at Arras.
Renard also developed the powered Renard Road Train, in which the trailers were powered by drive shafts from the forward power car, and each car was steered through a system of linkages attached to the car ahead of it. He also developed the concept of preferred numbers. (ISO 3)¹
Charles Renard remained in charge of the aeronautical establishment at Chalais-Meudon until his death. He committed suicide, 13 April 1905.
Arthur Constantin Krebs was born 16 November 1850 at Vesoul, France.
Krebs was a prolific inventor. Following his work with La France, he completed the development of Gymnote (Q1), the world’s first all-electric submarine. His work on automobiles was extensive. He developed the concept of the front engine/rear wheel drive (Systeme Panhard); engine balancing; caster in the steering and suspension system, which allowed the steering wheels to self-center; the steering wheel; shock absorbers; four-wheel drive and four-wheel steering, etc. He invented the electric brake dynomometer which is used to measure power output of engines.
Arthur Krebs died 22 March 1935.
¹ “Preferred numbers were first utilized in France at the end of the nineteenth century. From 1877 to 1879, Captain Charles Renard, an officer in the engineer corps, made a rational study of the elements necessary in the construction of lighter-than-air aircraft. He computed the specifications for cotton rope according to a grading system, such that this element could be produced in advance without prejudice to the installations where such rope was subsequently to be utilized. Recognizing the advantage to be derived from the geometrical progression, he adopted, as a basis, a rope having a mass of a grams per metre, and as a grading system, a rule that would yield a tenth multiple of the value a after every fifth step of the series. . . .” —ISO 17:1973, International Organization for Standardization
8 August 1929: The rigid airship Graf Zeppelin, LZ 127, under the command of Dr. Hugo Eckener, departed Lakehurst Naval Air Station, New Jersey, heading east across the Atlantic Ocean on the first circumnavigation by air. The flight was sponsored by publisher William Randolph Hearst, who had placed several correspondents aboard.
Graf Zeppelin was named after Ferdinand Adolf Heinrich August Graf von Zeppelin, a German general and count, the founder of the Zeppelin Airship Company. The airship was constructed of a lightweight metal structure covered by a fabric envelope. It was 776 feet (236.6 meters) long. Contained inside were 12 hydrogen-filled buoyancy tanks, fuel tanks, work spaces and crew quarters.
A gondola mounted underneath contained the flight deck, a sitting and dining room and ten passenger cabins. The LZ-127 was manned by a 36 person crew and could carry 24 passengers.
LZ 127 was powered by five water-cooled, fuel injected 33.251 liter (2,029.1 cubic inches) Maybach VL-2 60° V-12 engines producing 570 horsepower at 1,600 r.p.m., each. Fuel was either gasoline or blau gas, a gaseous fuel similar to propane. The zeppelin’s maximum speed was 80 miles per hour (128 kilometers per hour).
The route of the flight was from Lakehurst NAS to the LZ 127 home base at Friedrichshafen. Germany. After refueling, it continued across Europe, Russia and Siberia, non-stop to Tokyo, Japan, where it moored and refueled at the Kasumigaura Naval Air Station. This leg crossed 7,297 miles (11,743 kilometers) in 101 hours, 49 minutes. After five days in Japan, Graf Zeppelin headed east across the Pacific Ocean to Mines Field, Los Angeles, California. This was the first ever non-stop flight across the Pacific Ocean. The distance was 5,986 miles (9,634 kilometers) and took 79 hours, 54 minutes. The transcontinental flight from Los Angeles back to the starting point at Lakehurst NAS, 2,996 miles (4,822 kilometers), took 51 hours, 13 minutes.
The total elapsed time for the circumnavigation was 21 days, 5 hours, 31 minutes. The route covered 20,651 miles (33,234 kilometers). The actual flight time was 12 days, 12 hours, 13 minutes, an average of 68.786 miles per hour (110.7 kilometers per hour).
Graf Zeppelin made 590 flights and carried more than 13,000 passengers. It is estimated that it flew more than 1,000,000 miles. After the Hindenburg accident, it was decided to replace the hydrogen buoyancy gas with non-flammable helium. However, the United States government refused to allow the gas to be exported to Germany. With no other source for helium, in June 1938, Graf Zeppelin was deflated and placed in storage.
5 August 1908: While on a 24-hour demonstration flight from its base at Lake Constance, down the Rhine to Strasbourg and return, the airship Zeppelin LZ 4 stopped for emergency repairs to one of its engines.
While moored at Flugfeld Stuttgart-Echterdingen, the airship was caught by a storm which tore it away from its mooring. It crashed and caught fire. LZ 4 was completely destroyed.