AEREON III
Encyclopedia
The AEREON III was an experimental hybrid airship
Hybrid airship
"A hybrid airship is an aircraft that combines characteristics of heavier-than-air technology, fixed-wing aircraft or helicopter, and lighter-than-air , aerostat technology."[1]Examples include helicopter/airship hybrids intended for heavy lift applications and dynamic lift airships intended for...

 of rigid
Rigid airship
A rigid airship is a type of airship in which the envelope retained its shape by the use of an internal structural framework rather than by being forced into shape by the pressure of the lifting gas within the envelope as used in blimps and semi-rigid airships.Rigid airships were produced and...

 construction built by the AEREON Corporation
AEREON
AEREON is an aircraft manufacturer specialising in unique hybrid airships. It was founded in Princeton, New Jersey in 1959....

 in the early 1960s. Of unconventional design, the airship featured three gas envelopes attached side-by-side, with the connecting structures shaped as airfoil
Airfoil
An airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....

s to create extra lift as the craft moved forwards. Intended as a small prototype craft that would precede the development of much larger hybrid airships, the AEREON III was constructed between 1959 and 1965 but was destroyed during taxiing
Taxiing
Taxiing refers to the movement of an aircraft on the ground, under its own power, in contrast to towing or push-back where the aircraft is moved by a tug...

 tests in 1966 and scrapped without having flown. It was "the first rigid airship to be built since Graf Zeppelin II
LZ 130 Graf Zeppelin
The Graf Zeppelin II was the last of the great German rigid airships built by the Zeppelin Luftschiffbau during the period between the World Wars, the second and final ship of the Hindenburg class named in honor of Paul von Hindenburg...

".

Background

The AEREON Corporation had been founded in 1959 by Presbyterian minister and U.S. Naval Reserve chaplain turned airship enthusiast Monroe Drew and Navy airship veteran Lieutenant Commander John Fitzpatrick. The organization was named in honor of Solomon Andrews
Solomon Andrews (inventor)
Solomon Andrews of Perth Amboy, New Jersey invented the first dirigible airship. The difference of specific gravity between the balloon and the surrounding atmosphere could be converted by a system of inclined planes to steer the craft, without a motor. He referred to his propulsion as...

's 1863 airship Aereon, a three-hulled craft—like AEREON III—that could make forward progress without an engine by alternately dropping ballast and valving hydrogen. (Aereon II was Andrews's second airship, a single-hulled craft.)

AEREON III was designed by Fitzpatrick and constructed between 1959 and 1965 at Mercer County Airport
Trenton-Mercer Airport
Trenton-Mercer Airport , formerly known as Mercer County Airport, is a public airport located in Ewing, New Jersey, four miles northwest of the central business district of Trenton, a city in Mercer County, New Jersey...

 in Trenton, New Jersey
Trenton, New Jersey
Trenton is the capital of the U.S. state of New Jersey and the county seat of Mercer County. As of the 2010 United States Census, Trenton had a population of 84,913...

. The construction work was carried out by Everett Linkenhoker, an airship rigger hired on the recommendation of Aereon's consultant, the distinguished airship aviator and retired U.S. Navy Vice Admiral Charles Rosendahl.

Future versions of the airship were envisaged as being up to 1000 feet (304.8 m) long, possibly with nuclear propulsion
Nuclear aircraft
A nuclear aircraft is an aircraft powered by nuclear energy. Research into them was pursued during the Cold War by the United States and the Soviet Union as they would presumably allow a country to keep nuclear bombers in the air for extremely long periods of time, a useful tactic for nuclear...

. Even "thousand-foot automated Aereons moving in connected trains through the lower atmosphere" were foreseen by some of those involved.

Configuration

The AEREON III comprised three rigid hulls, each 83 feet (25.3 m) in length and 17 in 6 in (5.33 m) in maximum diameter, connected by truss
Truss
In architecture and structural engineering, a truss is a structure comprising one or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes. External forces and reactions to those forces are considered to act only at the nodes and result in...

 members. The connecting structures between the hulls were faired in an airfoil
Airfoil
An airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....

 section, and the aircraft as a whole functioned as an airfoil with an aspect ratio
Aspect ratio (wing)
In aerodynamics, the aspect ratio of a wing is essentially the ratio of its length to its breadth . A high aspect ratio indicates long, narrow wings, whereas a low aspect ratio indicates short, stubby wings....

 of 0.74. The design was intended to "maximize the dynamic lifting forces acting on the airship hull and to take the fullest advantage of these forces in flight." Each hull contained six gas cells, for a total lifting gas
Lifting gas
Because of the Archimedes' principle, a lifting gas is required for aerostats to create buoyancy. Its density is lower than that of air . Only certain lighter than air gases are suitable as lifting gases.- Hot Air :...

 volume of 40000 cubic feet (1,132.7 m³). There were ventral fins with rudders at the aft ends of the outer two hulls and elevons on the trailing edges of the connecting structures. The two-seat cockpit was located in the nose of the central hull.

Structure and materials

The hulls had a Zeppelin
Zeppelin
A Zeppelin is a type of rigid airship pioneered by the German Count Ferdinand von Zeppelin in the early 20th century. It was based on designs he had outlined in 1874 and detailed in 1893. His plans were reviewed by committee in 1894 and patented in the United States on 14 March 1899...

-type structure comprising seven 20-sided main rings, three intermediate rings between each pair of main rings, and wire bracing; however, the structural members were of Duralumin
Duralumin
Duralumin is the trade name of one of the earliest types of age-hardenable aluminium alloys. The main alloying constituents are copper, manganese, and magnesium. A commonly used modern equivalent of this alloy type is AA2024, which contains 4.4% copper, 1.5% magnesium, 0.6% manganese and 93.5%...

 tubing, rather than the built-up girders of earlier rigids. The structure was described as "half as heavy and twice as strong as the structural material in the ill-fated Hindenburg
LZ 129 Hindenburg
LZ 129 Hindenburg was a large German commercial passenger-carrying rigid airship, the lead ship of the Hindenburg class, the longest class of flying machine and the largest airship by envelope volume...

." The hulls were enclosed by a double-layer outer cover, comprising an outer Tedlar layer and an inner layer of ripstop nylon treated with dope
Aircraft dope
thumb|right|[[United Kingdom military aircraft serials|2699]] a [[World War I]] [[Royal Aircraft Factory B.E.2]] finished in a clear dopeAircraft dope is a plasticised lacquer that is applied to fabric-covered aircraft...

. The gas cells were also made of Tedlar. The fins were of sheet Duralumin on frames of the same material, joined primarily with epoxy resin rather than by riveting.

Landing gear

The airship had a tricycle undercarriage with a non-steerable nosewheel beneath the central hull and steerable (via a connection with the rudders) wheels at the tips of the ventral fins at the aft ends of the outer hulls. The nosewheel functioned as an "internal mooring mast
Mooring mast
A mooring mast, or mooring tower, is a structure designed to allow for the docking of an airship outside of an airship hangar or similar structure...

," with a telescopic strut that allowed the ship's angle of attack
Angle of attack
Angle of attack is a term used in fluid dynamics to describe the angle between a reference line on a lifting body and the vector representing the relative motion between the lifting body and the fluid through which it is moving...

 to be varied while moored (e.g. nose down to hug the ground or nose up in preparation for takeoff) and a tie-down fitting at its lower end.

Propulsion

The AEREON III was powered by a single engine located at the aft end of the central hull. This engine was reported in 1962 as being a Solar
Solar Turbines
Solar Turbines Incorporated, a wholly owned subsidiary of Caterpillar Inc., designs and manufactures industrial gas turbines for on- and off-shore electrical power generation, for marine propulsion and for producing, processing and transporting natural gas and oil. Solar Turbines is one of the...

 Titan gas turbine of 80 hp, but the engine eventually installed was described as a "four-cylinder McCullough" (sic—presumably McCulloch). The engine drove a 21 feet (6.4 m) diameter, two-bladed pusher propeller (actually a helicopter rotor
Helicopter rotor
A helicopter main rotor or rotor system is a type of fan that is used to generate both the aerodynamic lift force that supports the weight of the helicopter, and thrust which counteracts aerodynamic drag in forward flight...

 rotating in the vertical plane). The location of the propeller at the aft end of the hull was stated to assist in boundary layer control
Boundary layer control
Boundary layer control refers to methods of controlling the behaviour of fluid flow boundary layers. This holds particular interest in aeronautical engineering because drag may be reduced whilst achieving high lift ....

 and its cyclic pitch feature to facilitate low-speed control. AEREON patented this propulsion and control system in 1966. However, the propeller required shortening before trials commenced because of its "greatly excessive vibration."

Buoyancy control

Five propane
Propane
Propane is a three-carbon alkane with the molecular formula , normally a gas, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel for engines, oxy-gas torches, barbecues, portable stoves, and residential central...

 burners in each hull enabled the helium to be heated to increase lift; the ship would be about 400 pounds (181.4 kg) heavy (i.e. weight greater than static lift) with the gas cells 83 percent filled with helium, but heating the gas would increase the static lift by 800 pounds (362.9 kg). The helium could also be cooled by admitting air through vents in the noses of the hulls, with the assistance of blowers. The double-layer outer cover, mentioned above, facilitated thermal insulation of the gas cells. AEREON also patented the pressurization and buoyancy-control system, in 1965.
One source states that the AEREON IIIs buoyancy-control capabilities would allow it to fly using "gravity propulsion"—without the assistance of an engine—along the lines of Solomon Andrews's original Aereon but substituting helium heating for Andrews's dropping of ballast and helium cooling for his valving of hydrogen. However, Fitzpatrick is quoted elsewhere as "deplor[ing] such exaggerations."

Destruction

On April 15, 1966, the AEREON III was taxiing on a runway at Mercer County Airport in a 15 knots (29.4 km/h) crosswind when it failed to slow down, tried to turn at the end of the runway, and tilted over onto two wheels. One of the pilots jumped from the cockpit, and the airship then turned flat on its back. The second pilot then jumped straight down from the inverted cockpit, and the airship overturned a second time. According to John McPhee
John McPhee
John Angus McPhee is an American Pulitzer Prize-winning writer, widely considered one of the pioneers of creative nonfiction....

's book The Deltoid Pumpkin Seed, the remains of the AEREON III were "virtually bulldozed back into the hangar, arriving more or less in flakes." However, another source states that reconstruction into a new, larger AEREON IIIB was contemplated. This craft would have been 100 feet (30.5 m) long and 75 feet (22.9 m) in span, with a "metal-clad
Metal-clad airship
Metal-clad airships are airships which utilize a very thin, airtight metal envelope, rather than the usual rubber-coated fabric envelope. The shell may be either internally braced as with the designs of David Schwarz, or monocoque as in the ZMC-2...

, partially delta" shape. According to this source, the damaged AEREON III was eventually broken up "sometime in 1967."

The AEREON III was succeeded by the AEREON 26
AEREON 26
The AEREON 26 was an experimental aircraft developed to investigate lifting body design with a view to using its shape to create hybrid designs, part airship, part conventional aircraft...

, which had an entirely different, deltoid shape. The new aircraft inherited its predecessor's McCulloch engine, along with aluminum tubing from the structure of AEREON III and several of its instruments. One of the nosecones from AEREON III is reportedly in the Lighter-than-Air Society's collection in Akron, Ohio.
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