Detroit ZMC-2

Last updated

ZMC-2
Zmc-2 1929.jpg
RoleMetal-clad airship
National originUnited States
Manufacturer Detroit Aircraft Corporation
First flightAugust 19, 1929
Retired1941
StatusScrapped
Primary user U.S. Navy
Produced1926–29
Number built1
General characteristics (as built)
Displacement200,100 cu ft (5,666.2 m3)
Length148 ft 11 in (45.4 m)
Beam53 ft 2 in (16.2 m) (hull diameter)
Draft64 ft 6 in (19.7 m) (height)
Installed power220hp per engine
Propulsion2x Wright J-5 Whirlwind 9-cyl. air-cooled radial engines
Speed60 knots (110 km/h; 69 mph)
Range587  nmi (1,087 km; 676 mi)
Complement3
ArmamentNone

The ZMC-2 (Zeppelin Metal Clad 200,000 cubic foot capacity) [1] was the only successfully operated metal-skinned airship ever built. [2] Constructed at Naval Air Station Grosse Ile by The Aircraft Development Corporation of Detroit, [1] the ZMC-2 was operated by the U.S. Navy at Lakehurst, New Jersey from 1929 until its scrapping in 1941. While at Lakehurst it completed 752 flights, and logged 2265 hours of flight time. [3]

Contents

Development

The ZMC-2 was built in Grosse Ile, Michigan by the Aircraft Development Corporation, a division of Detroit Aircraft Corporation, on a site shared with, and later acquired by Naval Air Station Grosse Ile. [1] The ZMC-2 was the brainchild of Ralph Hazlett Upson, a balloonist and engineer who had previously won the Gordon Bennett Cup for balloon racing in Europe, bringing the cup to the United States for the first time. [4] Upson teamed up with Carl B. Fritsche of Detroit and together they formed the Detroit Aircraft Corporation, with backing from Henry Ford and Edsel Ford, as well as Charles Kettering of General Motors, Alex Dow, president of Detroit Edison, and William B. Stout, a local industrialist. [1] Chief of hull design was the young Czech-American designer Vladimir Pavlecka. [5] [ better source needed ]

The airship was constructed in a special hangar built in 1925 for the construction of the ZMC-2, and expandable for the construction of much larger metal-clad airships the company envisioned would be produced later. [1] The hangar was 120 feet (37 m) tall, with a floor that measured 120 by 180 feet (37 by 55 m). [3] It remained the largest structure on the Naval Air Station property until 1960, when it was dismantled and the roof reused in the construction of a bowling alley in nearby Trenton, Michigan. [6]

The ZMC-2 was nicknamed the "Tin Bubble" and was also sometimes called a "tinship". The skin was not tin but Alclad. The airship was roughly teardrop shaped and had eight small stabilizer fins, four of which had rudders. It was held together with over 3.5 million rivets, [7] which were applied by an innovative sewing machine-like device which produced airtight seams. [1]

The ZMC-2 was 52 feet (16 m) in diameter and 150 feet (46 m) feet long. [1] The control car was 24 feet (7.3 m) feet long by 6 feet (1.8 m) feet wide. [1] It contained three fuel tanks to give a maximum cruising range of about 600 miles (970 km). [4] The ZMC-2 was powered by two Wright Whirlwind J5 engines of 200 horsepower (150 kW) each, carried on outriggers and mounted in a tractor arrangement, rather than the pusher position usually employed on blimps. [1] At first the landing gear was an unusual hollow steel ball about the size and shape of an American football, mounted on a tripod attached to the car. [1] This was done to create a shape with less drag in order to guarantee the Navy's requirement of a 62 miles per hour (100 km/h) top speed. Later, after the ZMC-2 had attained this speed with ease, the ball was replaced with a conventional swivelling soft tire. [1]

The crew consisted of a pilot, copilot and flight engineer-navigator, with space for one or two additional passengers.

Assembly

The ZMC-2 was constructed out of Alclad, corrosion resistant aluminium sheet formed from high-purity aluminium surface layers metallurgically bonded to high strength aluminium alloy core material. [1] The result was about as strong as carbon or mild steel. [1] [ clarification needed ] The downside was that Alclad was thicker than sheet aluminum, making the ship several hundred pounds heavier than originally envisioned. [1] The aircraft was already under construction, and over 20 feet of the nose completed using duraluminum when the decision was made to switch to Alclad. [1] The reason for the switch was that duraluminum is highly susceptible to corrosion, particularly in a salt water environment, the exact sort of environment a Navy blimp operates in. [1] The ZMC-2 was the first aircraft constructed from Alclad in the US, and no previous experience could be drawn upon for its handling. [1]

To assemble the ZMC-2 a skin-riveting machine was developed by the Aviation Tool Co., a division of the Detroit Aircraft Corporation. [1] The device was invented by Edward J. Hill, who had come to work on the ZMC-2 after leaving the Naval Aircraft Factory in Philadelphia, Pennsylvania. [1] The machine consisted of an aluminum casting, weighing about 100 pounds, and was supported on springs from a framework that ran on concentric circular rails set into the floor of the hangar. There were two sets of circular rails, one at each end of the building. Three riveting machines were made, one for each set of tracks, and one for reserve when repairs might be needed. The reason for two sets of tracks was that the hull was built in two sections, front and rear. Each end started from a circular plate suspended from the hangar roof by a cable and free to rotate as each 18-inch (46 cm) wide strip Alclad was added. In this manner, each end of the ship slowly grew as succeeding rows were added, looking like a bulls eye at first and later like a huge inverted teacup. [1] Both sections were under construction continuously 24 hours a day, seven days a week, once the hull was started.

The riveting machine fed three small aluminum wires from large spools to make a seam about a quarter inch wide composed of three rivets, one above the other in a staggered pattern. [1] In theory the machine could sew about 50 feet of seam in an hour, but in practice about 10 or more feet was the average. [1] The sheets of Alclad used were eight to nine thousandths of an inch thick. [1] As the each section of the hull grew internal annular rings were added at appropriate distances to give stiffness and reinforcement to the hull skin. [1] In addition, lightweight longitudinal channels were added between the circular rings, giving the internal structure the appearance of a huge bird cage. [1]

The helium gas was contained by the hull only, no fabric was used to contain the helium. [1] Inside the hull were two large airbag cells, called ballonets, made of rubberized fabric and containing air. [1] These cells could be expanded or contracted to control pressure as the helium expanded or contracted with the heating or cooling of the atmosphere or to adapt to changes of atmospheric pressure with altitude, and to control fore and aft trim. [1] In operation the ZMC-2 was susceptible to heating and cooling effects of the sun causing it to pop and buckle in the evenings if pressure from blowers was not applied. [8] During its service life the ZMC-2 was found to have a gas diffusion rate much lower than that of fabric-hulled blimps, meaning that a much longer time would pass before additional helium needed to be added. [1]

As the airship neared completion a decision had to be made on how best to fill it with helium. Once the two halves were completed they were suspended horizontally from cables attached to the hangar ceiling, and the two halves were joined with a final array of rivets. [9] Since helium mixes freely with air and is hard to separate from it, it was impractical to pump helium directly into the airship until the air was removed. It was decided that the airship would first be filled with carbon dioxide (CO2), a heavy gas that mixes less freely with helium and which is easier to separate from helium. Once filled with CO2 the helium could be pumped in under pressure from valves at the top of the chamber, forcing the CO2 out through valves located on the bottom, and then recovering any helium that did mix with it. [9] Only a few weeks before this procedure was to begin a bright young engineer noted that once filled with CO2 the ZMC-2 would be many thousands of pounds heavier than when filled with air. The rest of the airship's assembly had to be postponed for several weeks while additional reinforcing panels and stronger connectors were attached in order to support the increased weight of the CO2 filled airship. [9]

Operations

The airship was first flown on August 19, 1929, and transferred to Lakehurst, New Jersey in October 1929. [10] The airship was nicknamed "the Tin Blimp". Its first Navy skipper was Red Dugan, who expressed reluctance at operating the airship, believing it unsafe. [11] Dugan's concerns were proven wrong, though he later lost his life in the crash of another airship, Akron. [11]

It was considered very successful as a sub-scale test vehicle, but the company that built it did not weather the Great Depression well, and by the time a successor might have been built, there was little interest in pursuing it. In the year before the Depression, the U.S. Army was seeking funding for an airship based on the ZMC-2, that would have been larger than the German Graf Zeppelin , and powered by eight engines of 600–800  hp (450–600  kW ; 610–810  PS )}. The U.S. Army planned to use it as a tender for air-launched aircraft, similar to plans the U.S. Navy had for future dirigibles. The $4.5 million need for construction was never approved by Congress. [12]

The ZMC-2 was operated with a zero internal pressure at speeds up to 20 miles per hour (32 km/h), sufficient for it to be considered a 'rigid' airship. [13] With its low fineness ratio of 2.83, the ZMC-2 was difficult to fly. [14] By 1936, the airship had travelled over 80,000 miles (130,000 km)[ clarification needed ] with little sign of corrosion. In its lifetime the ZMC-2 logged 752 flights and 2265 hours of flight time. [15] In its final years its use had dropped significantly. Between December 1938 and April 1941 it only logged five hours of flight time.

Considered by the Navy as too small for anti-submarine patrols, the aging ZMC-2 was decommissioned and scrapped in 1941 after nearly 12 years of service.

Operators

USA

Specifications (ZMC-2)

General characteristics

Performance

The ZMC-2 plays a key role in the Clive Cussler novel Cyclops (1986) in which it is fictionally saved from scrapping and renamed Prosperteer.

See also

Notes

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Morrow, Walker C. and Carl B. Fritsche. The Metalclad Airship ZMC-2. 1967.
  2. ↑ The 1897 airship of David Schwarz was the first airship that was metal-skinned, although Schwarz's ship had an internal framework rather than a monocoque design.
  3. 1 2 Outlaw 2004, p. 7
  4. 1 2 Morrow and Fritsche 1987
  5. ↑ "[Article]". The AOPA Pilot: Voice of General Aviation. AOPA (Aircraft Owners and Pilots Association). 24 (2): 53. 1981. Retrieved 17 January 2021.
  6. ↑ Melton 1970
  7. ↑ Sullivan 1988
  8. ↑ Althoff 2003
  9. 1 2 3 Morrow and Fritsche 1967, p. vi
  10. ↑ Pace, Montgomery, and Zitarosa 2003
  11. 1 2 Morrow and Fritsche 1967, p. v.
  12. ↑ "Metal Covered Airship To Carry Twenty Tons" 1931 , p. 552.
  13. ↑ Van Treuren 2007, p. 90
  14. ↑ Robinson, Douglas H. Giants in the Sky: A History of the Rigid Airship (Seattle: University of Washington Press, 1979), p. 225.
  15. ↑ Vaeth 2005, p. 69

Related Research Articles

<span class="mw-page-title-main">Airship</span> Powered lighter-than-air aircraft

An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air.

USS <i>Akron</i> U.S. Navy airship (1931–33) – purpose-built flying aircraft carrier

USS Akron (ZRS-4) was a helium-filled rigid airship of the U.S. Navy, the lead ship of her class, which operated between September 1931 and April 1933. It was the world's first purpose-built flying aircraft carrier, carrying F9C Sparrowhawk fighter planes, which could be launched and recovered while it was in flight. With an overall length of 785 ft (239 m), Akron and her sister ship Macon were among the largest flying objects ever built. Although LZ 129 Hindenburg and LZ 130 Graf Zeppelin II were some 18 ft (5.5 m) longer and slightly more voluminous, the two German airships were filled with hydrogen, and so the two US Navy craft still hold the world record for the largest helium-filled airships.

USS <i>Shenandoah</i> (ZR-1) United States Navy rigid airship

USS Shenandoah was the first of four United States Navy rigid airships. It was constructed during 1922–1923 at Lakehurst Naval Air Station, and first flew in September 1923. It developed the U.S. Navy's experience with rigid airships and made the first crossing of North America by airship. On the 57th flight, Shenandoah was destroyed in a squall line over Ohio in September 1925.

USS <i>Los Angeles</i> (ZR-3) United States naval airship

USS Los Angeles was a rigid airship, designated ZR-3, which was built in 1923–1924 by the Zeppelin company in Friedrichshafen, Germany, as war reparations. It was delivered to the United States Navy in October 1924 and after being used mainly for experimental work, particularly in the development of the American parasite fighter program, was decommissioned in 1932.

<span class="mw-page-title-main">Hangar</span> Closed structure to hold aircraft or spacecraft in protective storage

A hangar is a building or structure designed to hold aircraft or spacecraft. Hangars are built of metal, wood, or concrete. The word hangar comes from Middle French hanghart, of Germanic origin, from Frankish *haimgard, from *haim and gard ("yard"). The term, gard, comes from the Old Norse garðr.

<span class="mw-page-title-main">N-class blimp</span> American patrol airship

The N-Class, or as popularly known, the "Nan ship", was a line of non-rigid airships built by the Goodyear Aircraft Company of Akron, Ohio for the US Navy. This line of airships was developed through many versions and assigned various designators as the airship designation system changed in the post World War II era. These versions included airships configured for both anti-submarine warfare and airborne early warning (AEW) missions.

<span class="mw-page-title-main">Alclad</span>

Alclad is a corrosion-resistant aluminium sheet formed from high-purity aluminium surface layers metallurgically bonded to high-strength aluminium alloy core material. It has a melting point of about 500 °C (932 °F). Alclad is a trademark of Alcoa but the term is also used generically.

<span class="mw-page-title-main">Detroit Aircraft Corporation</span>

The Detroit Aircraft Corporation was incorporated in Detroit, Michigan on July 10, 1922, as the Aircraft Development Corporation. The name was changed in 1929.

The K-1 was an experimental blimp designed by the United States Navy in 1929. The K-1 was not the prototype of the later K-class blimps.

<span class="mw-page-title-main">Metal-clad airship</span>

Metal-clad airships are airships which have a very thin airtight metal envelope, rather than the usual fabric envelope. This shell may be either internally braced as with the designs of David Schwarz, or monocoque as in the ZMC-2. Only four ships of this type are known to have been built, and only two actually flew: Schwarz's aluminum ship of 1893 collapsed on inflation; Schwarz's second airship flew at Tempelhof, Berlin in 1897, landed but then collapsed; the ZMC-2 flew 752 flights between 1929 and scrapping in 1941; while the Slate City of Glendale, was built in 1929 but never flew.

<span class="mw-page-title-main">Naval Air Station South Weymouth</span> Airport in and Abington, Massachusetts

Naval Air Station South Weymouth was an operational United States Navy airfield from 1942 to 1997 in South Weymouth, Massachusetts. It was first established as a regular Navy blimp base during World War II. During the postwar era the base became part of the Naval Air Reserve Training Command, hosting a variety of Navy and Marine Corps reserve aircraft squadrons and other types of reserve units. Like most BRAC sites, environmental contamination was detected in 1986, and since 1993 numerous remedies and long term monitoring of ground water are in place. Since 2005, over 600 acres have been transferred to the affected towns for reuse, and in 2011 the Navy signed a $25 million contract to transfer its remaining land.

<span class="mw-page-title-main">Lakehurst Hangar No. 1</span> United States historic place

Hangar No. 1 is an airship hangar located at Naval Air Engineering Station Lakehurst in Manchester Township, in Ocean County, New Jersey, United States. It was the intended destination of the rigid airship LZ 129 Hindenburg prior to the Hindenburg disaster on May 6, 1937, when it burned while landing. Built in 1921, it is one of the oldest surviving structures associated with that period's development of lighter-than-air flight. It was designated a National Historic Landmark in 1968.

<span class="mw-page-title-main">Piasecki PA-97 Helistat</span> Experimental helicopter/airship by Piasecki Aircraft

The Piasecki PA-97 Helistat was an American experimental heavy-lift aircraft, built by Piasecki by fastening four H-34J helicopters to a framework beneath a helium-inflated blimp envelope. The sole prototype was lost during a test flight, killing a test pilot and injuring another four in the course of a single incident.

<span class="mw-page-title-main">Naval Air Station Grosse Ile</span>

Naval Air Station Grosse Ile was a Naval air station located on the southern tip of Grosse Ile, Michigan. It operated from 1927 until late 1969, and is now a township airport. During World War II NASGI was one of the largest primary flight training stations for Naval aviators, and RAF pilots. Among the many thousands of Navy pilots who began their careers at NASGI is game show host Bob Barker. Former President George H. W. Bush finished his active Navy career at NASGI attached to Torpedo Squadron 153(VT-153).

The Weeksville Dirigible Hangar is an airship manufacturing, storage and test facility originally built by the United States Navy in 1941 for servicing airships conducting anti-submarine patrols of the US coast and harbors. It is located on the former Naval Air Station Weeksville in Elizabeth City, North Carolina, approximately 2 miles southeast of the present day Coast Guard Air Station Elizabeth City.

In the nation's quest to provide security along its lengthy coastlines, air reconnaissance was put forth by the futuristic Rear Admiral William A. Moffett. Through his efforts, two Naval Air Stations were commissioned in the early 1930s to port the Naval Airships (dirigibles) which he believed capable of meeting this challenge.

The United States Navy proposed to the U.S. Congress the development of a lighter-than-air station program for anti-submarine patrolling of the coast and harbors. This program proposed, in addition to the expansion at Naval Air Station and Lakehurst, the construction of new stations. The original contract was for steel hangars, 960 ft (290 m) long, 328 ft (100 m) wide and 190 ft (58 m) high, helium storage and service, barracks for 228 men, a power plant, landing mat, and a mobile mooring mast.

There are three historic airship hangars at Moffett Field, in Mountain View in the southern San Francisco Bay Area, California. Hangar One is based on a structure of steel girders, while Hangars Two and Three are of wood. They are among the world's largest freestanding structures.

Unlike later blimp squadrons, which contained several airships, the large rigid airship units consisted of a single airship and, in the case of the USS Akron and USS Macon, a small contingent of fixed-wing aircraft.

<i>Akron</i>-class airship Type of aircraft

The Akron-class airships were a class of two rigid airships constructed for the US Navy in the early 1930s. Designed as scouting and reconnaissance platforms, the intention for their use was to act as "eyes for the fleet", extending the range at which the US Navy's Scouting Force could operate to beyond the horizon. This capability was extended further through the use of the airships as airborne aircraft carriers, with each capable of carrying a small squadron of airplanes that could be used both to increase the airship's scouting range, and to provide self-defense for the airship against other airborne threats.

References

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.