Tag Archives: Advanced High-Altitude Aerobody

Modern Airships – Part 2

Peter Lobner, Updated 3 April 2021

1. Introduction

Modern Airships is a three-part document that contains an overview of modern airship technology in Part 1 and links in Parts 1, 2 and 3 to more than 130 individual articles on historic and advanced airship designs.  This is Part 2.  Here are the links to the other two parts:

You’ll find a consolidated Table of Contents for all three parts at the following link.  This should help you navigate the large volume of material in the three documents.

Modern Airships – Part 2 begins with a summary graphic table identifying the airships addressed in this part, and concludes by providing links to 64 individual articles on those airships. A downloadable copy of Part 2 is available here:

If you have any comments or wish to identify errors in these documents, please send me an e-mail to:  PL31416@cox.net.

I hope you’ll find the Modern Airships series to be informative, useful, and different from any other single document on this subject.

Best regards,

Peter Lobner

 April 2021

2. Specific airships in Part 2

The airships reviewed in Modern Airships – Part 2 are summarized in the following set of graphic tables that are organized into the 11 categories listed below: 

  • Conventional, rigid and semi-rigid airships
  • Conventional, non-rigid airships (blimps)
  • Hybrid (semi-buoyant) airships
  • Hybrid thermal (Rozier) airships
  • Variable buoyancy, fixed volume airships
  • Variable buoyancy, variable volume airships
  • Variable buoyancy propelled airships
  • Stratospheric airships
  • Semi-buoyant plane / airship hybrids
  • Electro-kinetically (EK) propelled airships
  • Small LTA drones

Within each category, each page of the table is titled with the name of the category and is numbered (P2.x), where P2 = Modern Airships – Part 2 and x = the sequential number of the page in that category.  For example, “Stratospheric airships (P2.2)” is the page title for the second page in the “Stratospheric airships” category in Part 2.  There also are stratospheric airships addressed in Modern Airships – Parts 1 and 3.

Links to the individual Part 2 articles on these airships are provided in Section 3.  Some individual articles cover more than one particular airship.

Among the airships included in the above tables, more than 35 have flown.

Several airships that have not yet flown have well-established designs and their manufacturers seem to be poised to start building their full-scale prototype(s) and engaging aviation regulatory authorities in the long process leading to a type certificate for their production airships.  Several manufacturers have received orders that are conditional on having a type certificate.  Almost all are limited by a lack of funding to get from Point A (today) to Point B (having a type certificate).

The most promising new heavy-lift airship manufacturers identified in Part 2 are:

  • Flying Whales (France): The firm appears to have solid funding from diverse sources in France, China, Canada and Morocco, which should be adequate to fund the construction and flight testing of a prototype LCA60T airship.  Full-scale production facilities are planned in France, China and Canada and commercial airship operating infrastructure is being planned. In 2019, the LCA60T prototype maiden flight was expected to take place in 2021.  That date has slipped to 2024.
  • Varialift (UK):  The factory in France and the ARH-PT prototype are under construction, but the schedule for completing the prototype has slipped, perhaps by three years to 2022, primarily because of tenuous funding. Without a stronger funding stream, the future schedule is unpredictable.
  • Euro Airship (France): The firm claims that production-ready drawings exist for their Corsair and the larger DGPAtt.  When funding becomes available, it seems that they’re ready to go.
  • BASI (Canada): The firm has a well developed design in the MB-30T and a fixed-base operating infrastructure design that seems to be well suited for their primary market in the Arctic. When funding becomes available, it seems that they’re ready to go.
  • Millennium Airship (USA & Canada): The firm has well developed designs for their SF20T and SF50T SkyFreighters, has identified its industrial team for manufacturing, and has a business arrangement with SkyFreighter Canada, Ltd., which would become a future operator of SkyFreighter airships in Canada.  In addition, a development plan defines the work needed to build and certify a prototype and a larger production airship. When funding becomes available, it seems that they’re ready to go.
  • Aerosmena (AIDBA, Russia): The firm offers the latest designs for heavy-lift hybrid thermal (Rozier) “aeroplatforms,” which use two lift gases: helium and heated air.  The A20 will be the prototype for the entire family of Aerosmena aeroplatform. When funding becomes available, it seems that they’re ready to go.
  • Atlas LTA Advanced Technology (Israel): After acquiring the Russian firm Augur RosAeroSystems in 2018, Atlas is continuing to develop the ATLANT variable buoyancy, fixed volume heavy lift airship.  They also are developing a new family of non-rigid manned and unmanned blimps.  However, the development plans and schedules have not yet been made public.

These heavy-lift airships will be competing in the worldwide airship market with the leading candidates identified in Modern Airships – Part 1, which could enter the market in the same time frame if they get adequate funding:

  • Lockheed Martin (USA): LMH-1 hybrid airship
  • Hybrid Air Vehicles (UK): Airlander 10 hybrid airship
  • Aeros (USA): Aeroscraft ML866 / Aeroscraft Gen 2 variable buoyancy / fixed volume airship
  • Voliris (France): V932 NATAC & SeaBird semi-buoyant, inflated wing airships

For decades, there have been many ambitious projects that intended to operate an airship as a pseudo-satellite, carrying a heavy payload while maintaining a geo-stationary position in the stratosphere on a long-duration mission (days, weeks, to a year or more).  None were successful.  This led NASA in 2014 to plan the 20-20-20 airship challenge: 20 km altitude, 20 hour flight, 20 kg payload.  The challenge never occurred, but it highlighted the difficulty of developing an airship as a persistent pseudo-satellite.  The most promising new stratospheric airship manufacturers identified in Part 2 are:

  • Sceye Inc. (USA):  This small firm is developing and, since 2017, has been flight testing mid-size, multi-mission stratospheric airships. The firm also is building a new headquarters and manufacturing facility in New Mexico. Plans for stratospheric communications system flight tests in 2021 have been filed with the Federal Communications Commission. 
  • Thales Alenia Space (France): The firm is developing the multi-mission Stratobus.  Their latest round of funding from France’s defense procurement agency calls for a full-scale, autonomous Stratobus demonstrator airship to fly by the end of 2023, five years later than another demonstrator that was ordered in the original 2016 Stratobus contract, but not built.

China remains an outlier after the 2015 flight of the Yuanmeng stratospheric airship developed by         Beijing Aerospace Technology Co. & BeiHang.  The current status of the Chinese stratospheric airship development program is not described in public documents.

Among the many smaller airships identified in Part 2, the following manufacturers could have their airships flying in the early-to-mid 2020s if adequate funding becomes available.

  • Dirisolar (France): The firm has a well developed design for their five passenger DS 1500, which is intended initially for local air tourism, but can be configured for other missions.  When funding becomes available, it seems that they’re ready to go.
  • A-NSE (France):  The firm offers a range of aerostat and small airships, several with a novel tri-lobe, variable volume hull design.  Such aerostats are operational now, and a tri-lobe airship could be flying in the early 2020s.
  • Egan Airships (USA):  The PLIMP Model J drone has already flown and the Model J plane / blimp hybrid is the likely candidate for FAA type certification. When funding becomes available, it seems that they’re ready to go.
  • Solar Ship (Canada): The firm’s 24-meter Caracal semi-buoyant, inflated wing airship has already flown successfully.  However, that basic design did not scale up successfully. Hence, the larger Wolverine has been redesigned as a significantly different semi-buoyant aircraft.  Solar Ship has not described their current development and certification schedules.

There seems to be a proliferation of small LTA drone blimps and other small LTA drone vehicles.  Some were developed initially for military surveillance applications, but all are configurable and could be deployed in a range of interesting applications. 

The 2020s will be an exciting time for the airship industry.  We’ll finally get to see if the availability of several different heavy-lift airships with commercial type certificates will be enough to open a new era in airship transportation. Aviation regulatory agencies need to help reduce investment risk by reducing regulatory uncertainty and putting in place an adequate regulatory framework for the wide variety of advanced airships being developed.  Customers with business cases for airship applications need to step up, place firm orders, and then begin the pioneering task of employing their airships and building a worldwide airship transportation network with associated ground infrastructure.  This will require consistent investment over the next decade or more before a basic worldwide airship transportation network is in place to support the significant use of commercial airships in cargo and passenger transportation and other applications. Perhaps then we’ll start seeing the benefits of airships as a lower environmental impact mode of transportation and a realistic alternative to fixed-wing aircraft, seaborne cargo vessels and heavy, long-haul trucks.

3. Links to the individual articles

The following links will take you to 64 individual articles that address all of the airships identified in the preceding graphic table.

Conventional, rigid and semi-rigid airships:

Conventional, non-rigid airships (blimps):

Hybrid (semi-buoyant) airships:

Hybrid thermal (Rozier) airships:

Variable buoyancy, fixed volume airships:

Variable buoyancy, variable volume airships:

Variable buoyancy propulsion airships:

Stratospheric airships:

Semi-buoyant plane / airship hybrids:

Electro-kinetically (EK) propelled airships:

Small LTA drones:

Phoenix Makes Its First Flight With Variable Buoyancy Propulsion. What’s Old is New Again!

Peter Lobner

Updated 18 July 2019

1. Phoenix

The Phoenix Unmanned Aerial Vehicle (UAV) is a small, autonomous airship designed to serve as a very long endurance, high-altitude “atmospheric satellite” that is capable of station keeping using an innovative variable buoyancy propulsion system.  The UAV is intended for use in telecommunications and a range of other civil and military applications.

Phoenix development is being lead by a consortium of UK universities, businesses, and innovation centers, with a distribution of roles and responsibilities as shown in the following graphic.

Source:  https://phoenixuas.co.uk

This project runs for three years. It is one of several projects supported the UK’s Department for Business, Energy & Industrial Strategy (BEIS), through the Aerospace Technology Institute (ATI) and Innovate UK, to invest in “research and technology projects to deliver world leading aerospace technologies in the UK.”

The Phoenix project website is here: https://phoenixuas.co.uk

The Phoenix UAV is a small, variable buoyancy airship measuring 15 meters (49 feet) long, with a wingspan of 10.5 meters (34 feet).  The UAV’s teardrop-shaped fuselage is constructed from a Vectran fabric, with short wings and a cruciform tail made of carbon fiber composite material. Thin film solar panels on the wing and horizontal stabilizer surfaces generate electric power for the UAV’s systems and to charge an onboard battery that provides continuous power at night and during inclement weather.

Source:  https://phoenixuas.co.uk
Source:  https://phoenixuas.co.uk

The fuselage contains 120 cubic meters (4,238 cubic feet) of helium lifting gas (hydrogen is an alternative), a supply of lifting gas, and a separate inflatable 6 cubic meter (212 cubic feet) cell containing heavier air.  I would expect that the Phoenix is ballasted for near neutral buoyancy so that the control span of the buoyancy control system can produce both positive and negative buoyancy.

To increase buoyancy, air in the inflatable cell is released to the atmosphere via a vent in the tail.  If needed, lifting gas can be released to the gas envelope to gain positive buoyancy.  As the lighter-than-air Phoenix gains altitude, the aerodynamic surfaces generate forward momentum, propelling the UAV forward during the unpowered climb.  

At the top of the climb, buoyancy is decreased by pumping outside air into the inflatable cell, increasing the gross weight of the UAV. As the now heavier-than-air Phoenix enters an unpowered dive, the aerodynamic surfaces continue generating forward momentum to propel the UAV.

During an extended mission, the climb-dive cycle is repeated as often as needed to provide propulsion for controlling the position of the UAV.

First indoor flight.  Source: https://phoenixuas.co.uk

On 21 March 2019, the Phoenix UAV made its first successful flight indoors, covering about 120 meters (394 feet) and becoming the world’s first large variable buoyancy powered autonomous UAV. Outdoor tests will be conducted after the UK Civil Aviation Authority certifies the UAV.  As currently configured the developers expect that Phoenix can operate at altitudes up to about 914 meters (3,000 feet).

You can watch a short video of the first flight here:


But was it the first ever flight of an airship using variable buoyancy propulsion?

No, it wasn’t.  First there was Aereon in the 1860s and then there was AHAB in the early 2000s.

2. Aereon

Back in the 1860s, Dr. Solomon Andrews invented the directionally maneuverable, hydrogen-filled airship named Aereonthat used variable buoyancy and airflow around the airship’s gas envelope to provide propulsion without an engine.  The gas envelope on the original Aereon airship consisted of three side-by-side, cigar-shaped balloons, each with seven internal cells containing the hydrogen lifting gas. The balloons formed a gas envelope measuring 80 feet (24.4 meters) long and 13 feet (4 meters) wide. 

  • Buoyancy of the airship was controlled by venting some hydrogen lift gas or dropping some sand ballast.  
  • The angle-of-attack (pitch angle) of the gas envelope was controlled by moving the center of gravity of the gondola (i.e., by moving people in the gondola fore and aft as needed)
  • Propulsive force was generated by alternating between positive buoyancy (lighter-than-air) flight and negative buoyancy (heavier-than-air) flight, and by coordinating the pitch angle of the gas envelope. 
    • During a buoyant ascent, the pitch angle was adjusted to as much as 15 degrees up.  Air flow along the top surface of the envelope moved from bow to stern and drove the airship forward.   The airship can continue to ascend until it reaches its “pressure altitude” where the decreasing atmospheric air density reduces airship buoyancy from positive to neutral.
    • During a semi-buoyant descent, the pitch angle was adjusted to as much as 15 degrees down.  Air flow along the bottom surface of the envelope moved from bow to stern and continued to drive the airship forward.
  • Direction was controlled by a rudder at the stern of the airship
Source:  Popular Science Monthly, January 1932

Andrews first flew Aereon over Perth Amboy, NJ on 1 June 1863 and flew at least three times more.  With Aereon, he demonstrated the ability to fly in any direction, including against the wind, make broad 360 degree turns, and navigate back to and land at his starting point.  Aereon’s gondola could carry the pilot and three passengers.

On 5 July 1864, the US Patent Office issued Patent # 43,449 to Solomon Andrews for his invention of a balloon that was capable of directed flight and could even be flown against the wind.  You can read the patent here: https://patents.google.com/patent/US43449

Lithograph of Solomon Andrews’s first airship “Aereon”
Source: United States Library of Congress’s Prints and Photographs division,
digital ID cph.3b01438.

Andrews’ second airship, Aereon 2, had a different gas envelope design, described as “a flattened lemon, sharply pointed at both ends.”  Aereon 2 also used a different approach for controlling buoyancy.  The new approach used a complex set of ropes and pulleys to squeeze or release external pressure on the hydrogen gas bags, thereby changing their volume and how much air was being displaced.  Aereon 2 flew over New York City on 25 May and 5 June 1866. The second trip ended up about 30 miles away with a landing in Oyster Bay, Long Island. This was Andrews’ last flight. 

Source: Skinner Auctioneers

Andrews organized the Aerial Navigation Company, which was chartered in November 1865 for “the transportation of passengers, merchandise and other matter from place to place.”  The firm intended to build commercial airships and establish regular airship service between New York and Philadelphia.  During the post-Civil War economic crisis, many banks failed and Aerial Navigation Co. went bankrupt, ending the plans for the first commercial passenger and freight air service in the world.

Source: Worthpoint

3. Advanced High-Altitude Aerobody (AHAB)

In the early 2000s, the Physical Science Lab at New Mexico State University was developing the Advanced High-Altitude Aerobody (AHAB), which consisted of a large, solar-powered, non-rigid, winged aerobody with the payload suspended below on several retractable cables. Changing the length of the cables moved the center of gravity and thereby controlled the attitude of the aerobody. Changing the buoyancy of the aerobody caused it to climb or descend. As with the Phoenix UAV and Solomon Andrews’  Aereon, a forward propulsive force was generated during each climb or descent maneuver.  With this modest propulsion capability, AHAB was designed for station-keeping operations in near-space (very high altitude) where propellers would be ineffective.

In 2004, Mary Ann Stewart, et al., reported, “This superpressure balloon incorporates wing-like devices to give it a sleek aerodynamic shape. AHAB is designed to offset the effects of light winds by using a porpoising technique as necessary, trading altitude for horizontal motion. The craft is made up of a series of individual cells, and helium is pumped between cells to effect movement.”

Lt. Col Ed Tomme and Sigfred Dahl provided additional performance information, noting that such vehicles “will use a variety of unconventional buoyancy-modification schemes that allow vehicles to propel themselves by porpoising through the air at about 30 to 50 knots, enabling them to overcome all but the most unusual near-space winds.”

The AHAB airship.  Source: adapted from Air & Space Power Journal, Winter 2005, Volume XIX, No. 4, p. 47

In the 1-14 July 2019 issue of Aviation Week & Space Technology magazine, former AHAB program manager, Mike Fisher, commenting on the new Phoenix UAV, provided the following historical insights on AHAB: 

“The Aerobody was a solar-powered lighter-than-air vehicle (non-rigid rather than semi-rigid, as in the Phoenix) that pioneered the idea of using a ballonet to cause buoyancy and changes in center of gravity to enable propeller-less forward flight.

We took the concept far enough to demonstrate the validity of the underlying physics by building a subscale prototype that we successfully tested in indoor flight tests. Ultimately, the then-existing limits to photovoltaic cell and battery technology kept us from going past the prototype stage.”

What’s old is new again!

In the past two decades, winged underwater gliders implementing Andrews’ basic variable buoyance propulsion principle have been developed.  See the 2001 article, “Autonomous Buoyancy-driven Underwater Gliders,” which you can read here:


Now, the UK Phoenix team has demonstrated variable buoyancy propulsion in a small, unmanned airship, 156 years after Solomon Andrews first flew the much larger Aereon with passengers in Perth Amboy, NJ, and almost two decades after the indoor test flight of the subscale AHAB prototype at New Mexico State University.

Best wishes to the UK Phoenix team in their efforts to develop an operational variable buoyancy propulsion system for a modern airship.

Additional resources on the Phoenix UAV

Additional resources on Solomon Andrews and the Aereon

Additional resources on the Advanced High-Altitude Aerobody (AHAB)

Additional resources on buoyancy-driven airships