Tag Archives: Frank P. Lahm

12 August 1908

Signal Corps Dirigible No. 1 at Fort Myer, Virginia, 1908 (U.S. Army)

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.

Brigadier General James Allen, Chief Signal Officer, 1906–1913. (U.S. Army)

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.)

Signal Corps Dirigible No. 1 (SC-1) emerges from its shed at Fort Myer, Virginia, 3 August 1908. (Carl Harry Claudy/NASM-Claudy-205)

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.

Second Lieutenants Lahm and Fulois flying Signal Corps Dirigible No. 1 (SC-1) at Fort Myer, Virginia, 28 August 1908. (U.S. Air Force)

© 2017, Bryan R. Swopes

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2 August 1909

The Wright 1909 Military Flyer being fueled at Fort Myer, Virginia. Orville Wright is to the right of center in this photograph. The military officer is 1st Lieutenant Frank P. Lahm, Signal Corps, United States Army.  (U.S. Air Force)

2 August 1909: The United States Army Signal Corps purchased a Wright Flyer for $30,000. It became the first aircraft in the United States’ military inventory and was designated Signal Corps Airplane No. 1. The airplane was used to train Signal Corps pilots at Fort San Antonio, Texas, and was crashed and rebuilt several times. After just two years’ service, it was retired. The Army gave the airplane to the Smithsonian Institution.

During test flights that were conducted prior to acceptance by the Army, Orville Wright with Lieutenant Benjamin D. Fulois as a passenger (he was chosen because of his size and his ability to read maps) the Flyer achieved a two-way average 42.583 miles per hour (68.531 kilometers per hour), over a 5 mile (8.05 kilometers) course. The Signal Corps specification allowed a bonus of $2,500 per full mile per hour above 40 miles per hour. This increased the purchase price of the airplane from $25,000 to $30,000. The Army also required the airplane to be able to remain airborne for a minimum of one hour. Wright demonstrated its endurance at 1 hour, 12 minutes, 40 seconds.

1st Lieutenant Benjamin D. Fulois, Signal Corps, United States Army, and Orville Wright, at Fort Myer, Virginia, 1909. (U.S. Air Force)
1st Lieutenant Benjamin Delahauf Fulois, Signal Corps, United States Army, and Orville Wright, at Fort Myer, Virginia, 1909. By November 1917, Brigadier General Fulois was Chief of Air Service, American Expeditionary Forces. (U.S. Air Force)

The 1909 Military Flyer is a one-of-a-kind variant of the Wright Brothers’ Model A which was produced from 1907 to 1909. The airplane has shorter wings than the standard Model A, and slightly longer propeller blades which are turned at a different r.p.m. These changes were made to increase the Flyer’s speed through the air. The engine had been salvaged from the 1908 Model A which crashed at Fort Myer in 1908, severely injuring Orville Wright and killing Lieutenant Thomas E. Selfridge.

The Military Flyer is a two-place, single-engine biplane built of a wooden framework braced with wires. The wings, rudders and elevators are covered with muslin. The elevators are placed forward in canard configuration with rudders aft. Roll control was by the Wright Brothers’ patented wing-warping system.

Signal Corps Airplane no. 1, the Wright 1909 Military Flyer, at Fort Myer, Virginia, 1910. (U.S. Air Force)
Signal Corps Airplane No. 1, the Wright 1909 Military Flyer, at Fort Myer, Virginia, 1910. (U.S. Air Force)

As originally built (it was repaired and slightly modified during its two years in service) the airplane was 28 feet, 11 inches (8.814 meters) long with a wingspan of 36 feet, 6 inches (11.125 meters) and height of 8 feet, 1 inch (2.464 meters). The wings have a chord of 5 feet, 10 inches (1.778 meters) and vertical separation of 5 feet (1.524 meters). The lower wing has 2 feet, 3 inches (0.686 meter) of ground clearance. The elevators have a span of 15 feet, 5 inches (4.699 meters), a chord of 3 feet (0.914 meter) and vertical spacing of 3 feet (0.914 meter). The parallel rudders are 4 feet, 8½ inches (1.435 meters) tall with a chord of 1 foot, 8 inches (0.508 meter). Their lateral separation is also 1 foot, 8 inches (0.508 meter). The rudder pivot point is 15 feet, 11 inches (4.851 meters) aft of the wings’ leading edge. The airplane had an empty weight of 740 pounds (335.7 kilograms).

The Model A was powered by a single water-cooled, fuel-injected, 240.528 cubic-inch-displacement (3.942 liter) Wright vertical overhead-valve inline four-cylinder gasoline engine with 2 valves per cylinder and a compression ratio of 4.165:1. It produced 32 horsepower at 1,310 r.p.m. During three years of production (1908–1911) Wright “4-40” engines were built that operated from 1,325 to 1,500 r.p.m. Power output ranged from 28 to 40 horsepower. These engines weighed from 160 to 180 pounds (72.6–81.6 kilograms).

Two 9 foot (2.743 meter) diameter two-bladed counter-rotating propellers, driven by a chain drive, are mounted behind the wings in pusher configuration. They turned 425 r.p.m.

The Military Flyer could fly 42 miles per hour (67.6 kilometers per hour) and had endurance of one hour.

Early army officers who trained with Signal Corps Airplane No. 1 included Lieutenants Benjamin D. Fulois, Frank P. Lahm and Frederic E. Humphreys.

The unrestored Wright 1909 Military Flyer is in the collection of the Smithsonian Institution, displayed at the National Mall. A reproduction of the airplane is at the National Museum of the United States Air Force.

Signal Corps Airplane No. 1, the Wright 1909 Military Flyer, on display at the Early Flight gallery of the Smithsonian Institution National Mall building. (Photo by Eric Long, National Air and Space Museum, Smithsonian Institution)

© 2017, Bryan R. Swopes

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