The A-4 was built by the Goodyear company for the US Army in April 1919. She was the product of a post-world war I environment when the Army was struggling with how to employ the airship in military operations. In 1919, Germany dominated the field of airships and had used them successfully in reconnaissance and bombing operations. Germany already had "rigid" airships in WW I, and the US had none! So the acquisition of the A-4 was actually a very major milestone in the quest of the US Government to enter into the airship playground.
The A-4 was 95,000 cubic feet in volume, spanned 162 feet in length, and was 33 1/2 feet in diameter at is maximum girth. She relied on one Curtiss OX-5, 70 hp engine for propulsion and used a single, 2-blade propeller. Her useful lift was 2,224 pounds and she could sustain a cruise speed of 35 mph with a maximum speed of 46. She was limited to an altitude of 8,000 feet. (This means she could not ascend over the Rocky Mountains if she tried! But that, of course, is not the point! She was designed as an "entry point" for the US into the field of airships, and in that role, she performed admirably!)
The A-4 had a long an distinguished career. After acceptance by the Army on April, 22, 1919, she was delivered to Langley Field, Virginia and began trials as a training aircraft. Very early, given her ability to manage 12 hours of cruise time, one of her first "tests" was to carry Ralph Upson, the Chief Engineer for the Goodyear company, to Cleveland, Ohio where Mr. Upson was to deliver a speech on airship design to the Society of Automotive Engineers. During this test flight, the A-4 actually landed on the top of the Statler Hotel - the site of the Automotive Engineer meeting! (See photos herein).
In September, 1920, the A-4 flew in formation with two other training airships and participated in demonstrating radio communication with the ground. She was transferred to Scott Field, Illinois in July, 1922. In late 1922 she participated in experiments with free balloons, and on one occasion flew round trip and non-stop with sister airship, the Mullion, from Scott Field to Springfield, IL. In December, 1922, the A-4 even delivered "Santa Claus" to the Scott Field Officer's Club to the delight of party-goers. In February, 1923, she made a demonstration landing on a football field in Belleville, Illinois. Also in February, 1923, General Billy Mitchell flew on the A-4 during an inspection of the Army Airship School at Scott Field.
Actually, the end of the A-4 is shrouded in mystery! Airship author James Shock says in his "U.S. Army Airships 1908-1942", page 35, says the A-4 was "dismantled" sometime in 1923. A citation, the last I could find on the A-4, in the "Air Service Newsletter" for April 14, 1923 states: "AIRSHIP A-4 OVERHAULED. The Engineering Department at Scott Field, Ill., is taking advantage of the bad weather to improve the condition of the Airship A-4. A new Rolls-Royce, 6-cylinder motor is begin installed, with a four-blade propeller similar to the one used on the Mullion Airship. The new propeller will increase the speed of the ship and make for smoother flying." No further entry about the A-4 is found in any source I was able to find.
The mystery is that I came across an undated photo which appears to show the control car of the A-4, crashed on the ground! (See "Mystery: What became of the A-4?", below.) Not only was I unable to confirm or date the photo, but with no record of an accident, I simply had to throw up my hands and admit defeat!
The A-4 served admirably in a time when great experimentation on aerial warfare was being conducted in the U.S. Army. The A-4 served as the training vessel for Ambrose Clinton, and once carried Brigadier General Billy Mitchell in February 1923! (See "Air Service Newsletter" for March 5, 1923, page 4.) The fact that the fate of the A-4 is unknown is ignominious indeed.