Category Archives: Aeronautical

Modern Airships – Part 1

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 79 individual articles on historic and advanced airship designs.  This is Part 1.  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 1 begins with an overview of modern airship technology, continues with a summary table identifying the airships addressed in this part, and concludes by providing links to 22 individual articles on these airships. A downloadable copy of Part 1 is available here:

If you have any comments or wish to identify errors in this document, 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

August 2019

2.  Well-established benefits and opportunities, but a risk-averse market

For more than two decades, there has been significant interest in the use of modern lighter-than-air craft and hybrid airships in a variety of military, commercial and other roles, including:

  • Heavy cargo carriers operating point-to-point between manufacturer and end-user, eliminating inter-modal load transfers enroute
  • Heavy cargo carriers serving remote and/or unimproved sites not adequately served by other modes of transportation
  • Disaster relief, particularly in areas not easily accessible by other means
  • Persistent optionally-manned surveillance platforms for maritime surveillance / border patrol / search and rescue
  • Passenger airships
  • Commercial flying cruise liner / flying hotel
  • Airship yacht
  • Personal airship
  • Drone carrier
  • High altitude regional communications node

One of the very significant factors driving interest in modern airships is that they offer the potential to link isolated regions with the rest of the world while doing so in a way that should have lower environmental impacts than other transportation alternatives for those regions. This target market for airships exists in more than two-thirds of the world’s land area where more than half the world’s population live without direct access to paved roads and reliable ground transportation.

This matter is described well in a 21 February 2016 article by Jeanne Marie Laskas, “Helium Dreams – A new generation of airships is born,” which is posted on The New Yorker website at the following link:

https://www.newyorker.com/magazine/2016/02/29/a-new-generation-of-airships-is-born

In spite of the significant interest and the development of many promising airship designs, an actual worldwide airship cargo and passenger transportation industry has been very slow in developing.  To give you an example of how slow:

  • As of August 2019, the Zeppelin NT 07 is the only advanced airship that has been certified and is flying regularly in commercial passenger service. 
  • At the March 2019 Aviation Innovations Conference – Cargo Airshipsin Toronto, Canada, Solar Ship CEO Jay Godsall proposed an industry-wide challenge to actually demonstrate by July 2021 airships that can move a 3 metric ton (6,614 lb) standard 20 foot intermodal container configured as a mobile medical lab 300 km (186 mi) to a remote location. Godsall noted that this capability would be of great value if it did exist, for example, in support of relief efforts in Africa and other regions of the world.

So in spite of the airship industry having developed many designs capable of transporting 10 to 100 tons of cargo thousands of miles, today there is not a single airship that can transport a 3 metric ton (6,614 lb) payload 300 km (186 mi).

Why has the airship industry been so slow to develop? The bottom line has been a persistent lack of funding.  With many manufacturers having invested in developing advanced, detailed designs, the first to secure adequate funding will be able to take the next steps to build a manufacturing facility and a full-scale prototype airship, complete the airship certification process, and start offering a certified airship for sale.

There are a some significant roadblocks in the way:

  • No full-scale prototypes are flying:  The airship firms currently have little more than slide presentations to show to potential investors and customers.  There are few sub-scale airship demonstrators, but no full-scale prototypes.  The airship firms are depending on potential investors and customers making a “leap of faith” that the “paper” airship actually can be delivered.
  • Immature manufacturing capability:  While the airship industry has been good at developing many advanced designs, some existing as construction-ready plans, few airship firms are in the process of building an airship factory. The industrial scale-up factor for an airship firm to go from the design and engineering facilities existing today to the facilities needed for series production of full-scale airships is huge.  Several years ago, Russian airship manufacturer Augur RosAeroSystems proposed building a new factory to manufacture up to 10 ATLANT airships per year.  The funding requirement for that factory was estimated at $157 million.  The exact amount isn’t important.  No matter how you look at it, it’s a big number.  Large investments are needed for any airship firm to become a viable manufacturer.
  • Significant financial risk:The amount of funding needed by airship firms to make the next steps toward becoming a viable manufacturer exceeds the amount available from venture capitalists who are willing to accept significant risk. Private equity sources typically are risk averse. Public sources, or public-private partnerships, have been slow to develop an interest in the airship industry. The French airship firm Flying Whales appears to be the first to have gained access to significant funding from public institutions.  
  • Significant regulatory risk:Current US, Canadian and European airship regulations were developed for non-rigid blimps and they fail to address how to certify most of the advanced airships currently under development.  This means that the first airship manufacturers seeking type certificates for advanced airships will face uphill battles as they have to deal with aviation regulatory authorities struggling to fill in the big gaps in their regulatory framework and set precedents for later applicants.  It is incumbent on the aviation regulatory authorities to get updated regulations in place in a timely manner and make the regulatory process predictable for existing and future applicants.  
  • No airship operational infrastructure:  There is nothing existing today that is intended to support the operation of new commercial airships tomorrow.  The early airship operators will need to develop operating bases, hanger facilities, maintenance facilities, airship routes, and commercial arrangements for cargo and passengers.  While many airship manufacturers boast that their designs can operate from unimproved sites without most or all of the traditional ground infrastructure required by zeppelins and blimps, the fact of the matter is that not all advanced airships will be operating from dirt fields and parked outside when not flying.  There is real infrastructure to be built, and this will require a significant investment by the airship operators.
  • Steep learning curve for potential customers: Only the operators of the Zeppelin NT have experience in operating a modern airship today.  The process for integrating airship operations and maintenance into a customer’s business work flow has more than a few unknowns.  With the lack of modern airship operational experience, there are no testimonials or help lines to support a new customer. They’ll have to work out the details with only limited support.  Ten years from now, the situation should be vastly improved, but for the first operators, it will be a challenge.
  • Few qualified pilots and crew:  The airship manufacturers will need to work with the aviation regulatory authorities and develop programs for training and licensing new pilots and crew.  The British airship manufacturer Varialift has stated that one of the roles of their ARH-PT prototype will be to train future pilots.  

This uncertain business climate for airships seems likely to change in the early 2020s, when several different heavy-lift airships are expected to be certified by airworthiness authorities and ready for series production and sale to interested customers.  If customers step up and place significant orders, we may be able to realize the promise of airship travel and its potential to change our world in many positive ways.

3. Status of current aviation regulations for airships

As noted previously, current aviation regulations have not kept pace with the development of modern airship technology. In this section, we’ll take a look at the current regulations.

In the US, the Federal Aviation Administration’s (FAA) current requirements for airships are defined in the document FAA-P-8110-2, Change 2, “Airship Design Criteria (ADC),” dated 6 February 1995, which is available here:

https://www.faa.gov/aircraft/air_cert/design_approvals/airships/airships_regs/media/aceAirshipDesignCriteria.pdf

The ADC applies to non-rigid, near-equilibrium, conventional airships with seating for nine passengers or less, excluding the pilot, and it serves as the basis for issuing the type certificate required before a particular airship type can enter commercial service in the US.  The limited scope of this current regulation is highlighted by the following definitions contained in the ADC:

  • Airship:  an engine-driven, lighter-than-air aircraft, than can be steered.
  • Non-rigid: an airship whose structural integrity and shape is maintained by the pressure of the gas contained within the envelope.
  • Near-equilibrium: an airship that is capable of achieving zero static heaviness during normal flight operations.

Supplementary guidance for non-rigid, near-equilibrium, conventional airships is provided in FAA Advisory Circular (AC) No. 21.17-1A, “Type Certification – Airships,” dated 25 September 1992, which is available here:

https://www.faa.gov/documentlibrary/media/advisory_circular/ac_21-17-1a.pdf

The FAA’s ADC and the associated AC were written for blimps, not for the range of modern airships under development today.  For example, aerostatic lift is only one component of lift in modern hybrid airships, which also depend on powered lift from engines and aerodynamic lift during forward flight.  Hybrid airships are not “lighter-than-air” and cannot achieve zero static heaviness during normal operations, yet they are an important class of airships being developed in several countries.  In addition, almost all modern airships, except blimps, have rigid or semi-rigid structures that enable them to carry heavy loads and mount powerful engines that cannot possibly be handled by a non-rigid airship.

Recognizing the absence of an adequate regulatory framework for modern airships, civil aviation authorities of Germany and Netherlands developed supplementary guidance to the European Joint Aviation Requirements (JAR-25) and the FAA’s ADC for a category of airships called “Transport Airships,” which they define as follows:

“The transport category is defined for multi-engined propeller driven airships that have a capacity of 20 or more passengers (excluding crew), or a maximum take-off mass of 15,000 kg or more, or a design lifting gas volume of 20,000 m3or more, whichever is greater.”

These supplementary requirements are contained in the document “Transport Airship Requirements” (TAR), dated March 2000, which you will find at the following link:

https://www.faa.gov/aircraft/air_cert/design_approvals/airships/airships_regs/media/aceAirshipTARIssue1.pdf

So, this is the status of US and European airship regulations today.  

In the US, Lockheed-Martin currently is in the process of working with the FAA to get a type certificate for their semi-buoyant, hybrid airship, the LMH-1.  Clearly, they are dealing with great regulatory uncertainty.  Hopefully, the LMH-1 type certification effort will be successful and serve as a precedent for later applicants. 

4. Lifting gas

In the US, Canada and Europe, aviation regulations only allow the use of non-flammable lifting gas:

  • FAA ADC:  “The lifting gas must be non-flammable.” (4.48)
  • TAR: “The lifting gas must be non-flammable, non-toxic and non-irritant” (TAR 893)
  • Canadian Air Regulations:  “Hydrogen is not an acceptable lifting gas for use in airships.” (541.7)

Without hydrogen, the remaining practical choices for lifting gas are  helium and hot air. A given volume of hot air can lift only about one-third as much as the same volume of helium, making helium the near-universal choice, with hot air being relegated to a few, small thermal airships.

The current high price of helium is a factor in the renewed interest in hydrogen as a lifting gas.  It’s also a key selling point for thermal airships.  Most helium is produced as a byproduct from natural gas production. Helium is not “rare.” Only a very small fraction of helium available in natural gas currently is recovered, on the order of 1.25%.  The remainder is released to the atmosphere. The helium recovery rate could be higher, but is not warranted by the current market for helium.  Helium is difficult to store.  The cost of transportation to end-users is a big fraction of the market price of helium.

Hydrogen provides 10% more lift than helium.  It can be manufactured easily at low cost and can be stored.  If needed, hydrogen can be produced with simple equipment in the field.  This could be an important capability for recovering an airship damaged and grounded in a remote region.  One airship concept described in Modern Airships – Part 3, the Aeromodeller II, is designed for using hydrogen as the lifting gas and as a clean fuel (zero greenhouse gases produced) for its propulsion engines.  A unique feature of this airship concept is an on-board system to generate more hydrogen when needed from the electrolysis of water ballast.

A technique for preventing hydrogen flammability is described in Russian patent RU2441685C2, “Gas compound used to prevent inflammation and explosion of hydrogen-air mixtures,” which was submitted in 2010 and posted in 2012. This technique appears to be applicable to an airship using hydrogen as its lifting gas.  You can read the patent at the following link: https://patents.google.com/patent/RU2441685C2/en

The Canadian airship firm Buoyant Aircraft Systems International (BASI) is a proponent of using hydrogen lifting gas.  Anticipating a future opportunity to use hydrogen, they have designed their lifting gas cells to be able to operate with either helium or hydrogen.  BASI claims that lifting gas cells designed originally for helium lifting gas cannot later be used with hydrogen lifting gas.

Regulatory changes will be required to permit the general use of hydrogen lifting gas in commercial airships.  Time will tell if that change ever occurs.

Even with the needed regulatory changes, the insurance industry will have to deal with the matter of insuring a hydrogen-filled airship. 

5.  Types of modern airships

The term “aerostat” broadly includes all lighter than air vehicles that gain lift through the use of a buoyant gas. Aerostats include unpowered balloons (tethered or free-flying) and powered airships. 

The following types of powered airships are described in this section:  

  • Conventional airships
  • Semi-buoyant airships and aircraft
  • Variable buoyancy airships
  • Helistats (airship – helicopter hybrid)  
  • Thermal (hot air) airships

5.1  Conventional airships

Conventional airships are lighter-than-air (LTA) vehicles that operate at or near neutral buoyancy. The lifting gas (helium) generates approximately 100% of the lift at low speed, thereby permitting vertical takeoff and landing (VTOL) operations and hovering with little or no lift contribution from the propulsion / maneuvering system.  Various types of propulsors may be used for cruise flight propulsion and for low-speed maneuvering and station keeping. 

Airships of this type include non-rigid blimps, rigid zeppelins, and semi-rigid airships.

  • Non-rigid airships (blimps): These airships have a flexible envelope that defines the shape of the airship, contains the lifting gas cells and ballonets for buoyancy management, and supports the load of a gondola, engines and payload.
  • Rigid airships (zeppelins):These airships have a lightweight, rigid airframe that defines their exterior shape.  The rigid airframe supports the gondola, engines and payload.  Lifting gas cells and ballonets are located within the rigid airframe.
  • Semi-rigid airships:  These airships have a rigid internal spine or structural framework that supports loads. A flexible envelope is installed over the structural framework and contains the lifting gas cells and ballonets.

The Euro Airship DGPAtt and the Flying Whales LCA60T are examples of rigid conventional airships.

The Zeppelin NT and the SkyLifter are examples of semi-rigid conventional airships.

After being loaded and ballasted before flight, conventional airships have various means to control the in-flight buoyancy of the airship. Control can be exercised over ballast, lifting gas and the ballonets as described below.

Controlling  buoyancy with ballast:  

Many conventional airships require adjustable ballast (i.e., typically water or sand) that can be added or removed as needed to establish a desired net buoyancy before flight.  Load exchanges (i.e., taking on / discharging cargo or passengers) can change the overall mass of an airship and may require a corresponding ballast adjustment. If an airship is heavy and the desired buoyancy can’t be restored with the ballonets or other means, ballast can be removed on the ground or may need to be dumped in flight to increase buoyancy.

Controlling  buoyancy with lifting gas:  

However, temperature differentials between the lifting gas and the ambient air will affect the aerostatic lift produced by the lifting gas.  To exploit this behavior, some airships can control buoyancy using lifting gas heaters / coolers to manage gas temperature.  

The lifting gas inside an airship’s gas cells is at atmospheric pressure.  Normally, there is no significant loss (leakage) of lifting gas to the environment.  A given mass of lifting gas will create a constant lift force, regardless of pressure or altitude, when the lifting gas is at equal pressure and temperature with the surrounding air. Therefore, a change in altitude will not change the aerostatic lift.  

The lifting gas heaters are important for operation in the Arctic, where a cold-soak in nighttime temperatures may result in the lifting gas temperature lagging behind daytime ambient air temperature.  This temperature differential would result in a loss of lift until lifting gas and ambient air temperatures were equal.

Conversely, operating an airship in hot regions can result in the lifting gas temperature rising above ambient air temperature (the lifting gas becomes “superheated”), thereby increasing buoyancy. To restore buoyancy in this case, some airships have coolers (i.e., helium-to-air heat exchangers) in the lifting gas cells to remove heat from the lifting gas.

As described by Boyle’s Law, pressure (P) and gas volume (V) are inversely proportional at a constant temperature according to the following relationship:  PV = K, where K is a constant.  As an airship ascends, atmospheric pressure decreases.  This means that a fixed mass of lifting gas will expand within the lifting gas cells during ascent, and will contract within the lifting gas cells during descent.  As described previously, this lifting gas expansion and contraction does not affect the magnitude of the aerostatic lift as long as the lifting gas is at equal pressure and temperature with the surrounding air.

If an airship is light and the desired buoyancy cannot be restored with the ballonets or lifting gas coolers, it is possible to vent some lifting gas to the atmosphere to decrease aerostatic lift. 

Controlling  buoyancy with ballonets:

The airship hull / envelope is divided into sealed lifting gas volumes and separate gas volumes called “ballonets” that contain ambient air. The ballonets are used to compensate for modest changes in buoyancy by inflating them with small fans or venting them to the atmosphere to change the gross weight of the airship.  Fore and aft ballonets can be operated individually to adjust the trim (pitch angle) of the airship. 

As the airship gains altitude, external air pressure decreases, allowing the helium gas volume to expand within the gas envelope, into space previously occupied by the air in the ballonets, which vent a portion of their air content overboard. The airship reaches its maximum altitude, known as its “pressure height,” when the helium gas volume has expanded to fill the gas envelope and the ballonets are empty.  At this point, the airship’s mass is at a minimum and the helium lifting gas can expand no further.

On the ground, the ballonets may be inflated with air to make the airship negatively buoyant (heavier-than-air) to simplify ground handling. To takeoff, the ballonets would be vented to the atmosphere, reducing the mass of air carried by the airship.

To descend, a low-pressure fan is used to inflate the ballonets with outside air, adding mass. As the airship continues to descend into the denser atmosphere, the helium gas volume continues to contract and the ballonets become proportionately larger, carrying a larger mass of air.  Ballonet inflation / venting is controlled to manage buoyancy as the airship approaches the ground for a landing.

In flight, inflating only the fore or aft ballonet, and allowing the opposite ballonet to deflate, will make the bow or stern of the airship heavier and change the pitch of the airship.  These operating principles are shown in the following diagrams of a blimp with two ballonets, which are shown in blue.

Blimp with ballonets (blue).  Source: zeppelinfan.de

5.2  Semi-buoyant hybrid airships

Hybrid airships are heavier-than-air (HTA) vehicles. The term “semi-buoyant” means that the lifting gas provides only a fraction of the needed lift (typically 60 – 80%) and the balance of the lift needed for flight is generated by other means, such as vectored thrust engines and aerodynamic lift from the fuselage and wings during forward flight.

Sources of lift for a semi-rigid, hybrid airship.  Source: DoD 2012

Basic characteristics of hybrid airships include the following:

  • This type of airship requires some airspeed to generate aerodynamic lift. Therefore, it typically makes a short takeoff and landing (STOL).  
  • Some hybrid airships may be capable of limited VTOL operations (i.e., when lightly loaded, or when equipped with powerful vectored thrust engines).
  • Like conventional airships, the gas envelope in hybrid airship is divided into lifting gas volumes and separate ballonet volumes containing ambient air. 
  • Hybrid airships are heavier-than-air and are easier to control on the ground than conventional airships.

There are two types of hybrid airships:  semi-rigid and rigid.  

  • Semi-rigid hybrid airships:  These airships have a structural keel or spine to carry loads, and a large, lifting-body shaped inflated fuselage containing the lifting gas cells and ballonets.  Operation of the ballonets to adjust net buoyancy and pitch angle is similar to their use on conventional airships.  These wide hybrid airships may have separate ballonets on each side of the inflated envelope that can be used to adjust the roll angle.  While these airships are heavier-than-air, they generally require adjustable ballast to handle a load exchange involving a heavy load.
  • Rigid hybrid airships:  These airships have a more substantial structure that defines the shape of the exterior aeroshell. The “hard” skin of the airship may be better suited for operation in Arctic conditions, where snow loads and high winds might challenge the integrity of an inflated fuselage of a semi-rigid airship. Otherwise, the rigid hybrid airship behavior is similar to a semi-rigid airship. 

The Lockheed-Martin LMH-1 is an example of a semi-rigid hybrid airship.  The AeroTruck being developed by Russian firm Airship GP is an example of a rigid hybrid airship.

5.3  Semi-buoyant aircraft

Semi-buoyant aircraft are heavier-than-air, rigid, winged aircraft that carry a large helium volume to significantly reduce the weight of the aircraft and improve its load-carrying capability.  Aerostatic lift provides a smaller fraction of total lift for a semi-buoyant aircraft, like a Dynalifter, than it does for a semi-buoyant, hybrid airship.

A semi-buoyant aircraft behaves much like a conventional aircraft in the air and on the ground, and is less affected by wind gusts and changing wind direction on the ground than a hybrid airship.

The semi-buoyant aircraft has some flexibility for loading and discharging cargo without having to be immediately concerned about exchanging ballast, except in windy conditions.

The Aereon Corporation’s Dynairship and the Ohio Airships Dynalifter are examples of semi-buoyant aircraft.

5.4  Variable buoyancy airships

Variable buoyancy airships are rigid airships that can change their net lift, or “static heaviness,” to become LTA or HTA as the circumstances require.  Basic characteristics of variable buoyancy airships include the following:

  • Variable buoyancy airships are capable of VTOL operations and hovering, usually with a full load.
  • The buoyancy control system may enable in-flight load exchanges from a hovering airship without the need for external ballast.
  • On the ground, variable buoyancy airships can make themselves heavier-than-air to facilitate load exchanges without the need for external infrastructure or ballast.
  • It is not necessary for a “light” airship to vent the lifting gas to the atmosphere.

Variable buoyancy / fixed volume airships

Variable buoyancy commonly is implemented by adjusting the net lift of a fixed volume airship.  For example, a variable buoyancy / fixed volume airship can become heavier by compressing the helium lifting gas or ambient air:

  • Compressing some of the helium lifting gas into smaller volume tanks aboard the airship reduces the total mass of helium available to generate aerostatic lift.
  • Compressing ambient air into pressurized tanks aboard the airship adds mass (ballast) to the airship and thus decreases the net lift.

The airship becomes lighter by venting the pressurized tanks:

  • Compressed helium lifting gas is vented back into the helium lift cells, increasing the mass of helium available to generate aerostatic lift.
  • Compressed air is vented to the atmosphere, reducing the mass of the airship and thus increasing net lift.

The Aeros Aeroscraft Dragon Dreamand the Varilift ARH-50 are examples of variable buoyancy / fixed volume airships.

Variable buoyancy / variable volume airships

Variable buoyancy also can be implemented by adjusting the total  volume of the helium envelope without changing the mass of helium in the envelope. 

  • As the size of the helium envelope increases, the airship displaces more air and the buoyant force of the atmosphere acting on the airship increases. Static heaviness decreases.
  • Likewise, as the size of the helium envelope decreases, the airship displaces less air and the buoyant force of the atmosphere acting on the airship decreases. Static heaviness increases.

The EADS Tropospheric Airship is an example of a variable buoyancy / variable volume airship.

5.5 Helistats (airship / helicopter hybrid)

There have been many different designs of airship / helicopter hybrid aircraft (a helistat) in which the airship part of the hybrid aircraft carries the weight of the aircraft itself and helicopter rotors deployed around the base of the airship work in concert to propel the aircraft and to lift and deliver heavy payloads without the need for an exchange of ballast.

The Piasecki PA-97 and the Boeing  / Skyhook International SkyHook JLH-40 are examples of helistats.

5.5 Thermal (hot air) airships

Thermal airships use hot air as the lifting gas in place of helium or hydrogen. A given volume of hot air can lift only about one-third as much as the same volume of helium.  Therefore, the gas envelope on a thermal airship is proportionally larger than it would be on a comparable airship using helium as the lifting gas. 

The non-rigid GEFA-Flug four-seat AS-105GD/4 and six-seat AS-105GD/6 and the semi-rigid, two-seat Skyacht Personal Blimp are examples of current thermal airships that use propane burners to produce the hot air for lift.  Pitch can be controlled with fore and aft burners.  There are no ballonets.

6. How does an airship pick up and deliver a heavy load? 

The term “load exchange” refers to the pickup and delivery of cargo by an airship, with or without an exchange of external ballast to compensate for the mass of cargo being moved on or off the airship.  This isn’t a simple problem to solve.

The problem of buoyancy control

In Marie Laskas’ article, Igor Pasternak, CEO of airship manufacturer Worldwide Aeros Corp. (Aeros), commented on the common problem facing all airships when a heavy load is delivered:

“The biggest challenge in using lighter-than-air technology to lift hundreds of tons of cargo is not with the lifting itself—the larger the envelope of gas, the more you can lift—but with what occurs after you let the stuff go. ‘When I drop the cargo, what happens to the airship?’ Pasternak said. ‘It’s flying to the moon.’ An airship must take on ballast to compensate for the lost weight of the unloaded cargo, or a ground crew must hold it down with ropes.”

Among the many current designers and manufacturers of large airships, the matter of maintaining the airship’s net buoyancy within certain limits while loading and unloading cargo and passengers is handled in several different ways depending on the type of airship involved.  Some load exchange solutions require ground infrastructure at fixed bases and/or temporary field sites for external ballast handling, while others require no external ballasting infrastructure and instead use systems aboard the airship to adjust buoyancy to match current needs or provide vectored thrust (or suction) to temporarily counteract the excess buoyancy.  The solution chosen for managing airship buoyancy during a load exchange strongly influences how an airship can be operationally employed and where it can pickup and deliver its payload.

Additional problems for airborne load exchanges

Several current designers and manufacturers of large airships report that their airships will have the ability to conduct airborne load exchanges of cargo from a hovering airship.  Jeremy Fitton, the Director of SkyLifter, Ltd., described the key issues affecting a precision load exchange executed by a hovering airship as follows:

“The buoyancy management element of (an airborne) load-exchange is not the main control problem for airships. Keeping the aircraft in a geo-stationary position – in relation to the payload on the ground – is the main problem, of which buoyancy is a component.”

The matters of precisely maintaining the airship’s geo-stationary position throughout an airborne load exchange and controlling the heading of the airship and the suspended load are handled in different ways depending on the type of airship involved.  The time required to accomplish the airborne load exchange can be many minutes or much longer, depending on the weight of the cargo being picked up or delivered and the time it takes for the airship to adjust its buoyancy for its new loaded or unloaded condition. Most of the airships offering an airborne load exchange capability are asymmetrical (i.e., conventional “cigar shaped” or hybrid aerobody-shaped) and must point their nose into the wind during an airborne load exchange.  Their asymmetrical shape makes these airships vulnerable to wind shifts during the load exchange. The changing cross-sectional area exposed to the wind complicates the matter of maintaining a precise geo-position with an array of vectoring thrusters. 

During such a delivery in variable winds, even with precise geo-positioning over the destination, the variable wind direction may require the hovering airship to change its heading slightly to point into the wind. This can create a significant hazard on the ground, especially when long items, such as a wind turbine blade or long pipe segment are being delivered.  For example, the longest wind turbine blade currently in production is the GE Haliade-X intended for off-shore wind turbine installations.  This one-piece blade is 107 meter (351 ft) long.  A two degree change in airship heading could sweep the long end of the blade more than three meters (10 feet), which could be hazardous to people and structures on the ground.

Regulatory requirements pertaining to load exchanges

The German / Netherlands “Transport Airship Requirements” (TAR), includes the following requirement for load exchanges in TAR 80, “Loading / Unloading”:

(c) During any cargo exchange…the airship must be capable of achieving a safe free flight condition within a time period short enough to recover from a potentially hazardous condition.”

This requirement will be a particular challenge for airships designed to execute an airborne load exchange from a hovering airship.

The CargoLifter approach to an airborne load exchange

One early approach for delivering a load from a hovering airship was developed for the CargoLifter CL160.  As described on the Aviation Technology website (https://www.aerospace-technology.com/projects/cargolifter/), the CL160 would have performed an in-flight delivery of cargo as follows:

“The airship hovers at about 100 m above the ground and a special loading frame, which is fixed during flight to the keel of the airship, is then rigged with four cable winches to the ground, a procedure which is to assure that the airship’s lifting gear stays exactly above the desired position. Ballast water is then pumped into tanks on the frame and the payload can be unloaded. The anchor lines are released and the frame is pulled back into the payload bay of the airship.”In a 2002 test using a heavy-lift CargoLifter CL75 aerostat as an airship surrogate, a 55 metric ton German mine-clearing tank was loaded, lifted and discharged from the loading frame as water ballast was unloaded and later reloaded in approximately the same time it took to secure the tank in the carriage (several minutes).  In this test, the 55 metric tons cargo was exchanged with about 55 cubic meters (1,766 cubic feet, 14,530 US gallons) of water ballast.

The SkyLifter approach to an airborne load exchange

One airship design, the SkyLifter, addresses the airborne load exchange issues with a symmetrical, disc-shaped hull that presents the same effective cross-sectional area to a wind coming from any direction. This airship is designed to move equally well in any direction (omni-directional), simplifying airship controls in changing wind conditions, and likely giving the SkyLifter an advantage over other designs in conducting a precision airborne load exchange.

You’ll find more information on airship load exchange issues in a December 2017 paper by Charles Luffman, entitled, “A Dissertation on Buoyancy and Load Exchange for Heavy Airships (Rev. B)”, which is available at the following link:  

https://www.luffships.com/wp-content/uploads/2018/02/buoyancy_and_load_exchange.pdf

7. The scale of large cargo airships

Some of the advanced airship concepts being developed, especially for future heavy-lift cargo carriers, will result in extremely large air vehicles on a scale not seen since the heyday of the giant zeppelins in the 1930s.  Consider the following semi-rigid hybrid airships shown to scale with contemporary fixed-wing cargo aircraft.

Size comparison for hybrid airships sized for various lift applications.  
Source: DoD 2012

8. Specific airships in Part 1

The airships reviewed in Part 1 are summarized in the following set of tables, which include many heavy-lift cargo airships. In addition, there are several examples of semi-buoyant aircraft, helistats and thermal (hot air) airships.  Links to the 22 individual articles on these airships are provided at the end of this document.

The CargoLifter CL160, helistats, Megalifter, Aereon Dynairship and Project Walrus are included because they are of historical interest as early, though unsuccessful, attempts to develop large cargo airships. Concepts and technologies developed on these airship projects have promoted the development of other modern airships.

Among the airships in the above tables, the following have flown:  

  • Zeppelin NT 07 
  • Skybus 80K
  • Aeros Aeroscraft Dragon Dream
  • Piasecki PA-97
  • Dynalifter DL-100
  • Aereon 26
  • ATG / SkyCat Group SkyKitten
  • Hybrid Air Vehicles HAV-3 & HAV-304
  • Hybrid Air Vehicles Airlander 10
  • Lockheed Martin P-791
  • Volaris 901 & 902
  • GEFA-Flug AS-105GD/4 & AS-105GD/6 
  • Skyacht Personal Blimp

As of August 2019, the Zeppelin NT 07 is the only advanced airship that has been certified and is flying regularly in commercial passenger service.  The simpler GEFA-Flug and Skyacht thermal (hot air) airships also are flying regularly. The others that have flown have been retired.  The remaining airships in the Part 1 tables are under development or remain as concepts only. 

Among the airships in the above tables, several cargo airships are likely to receive their airworthiness certification in the next several years. The leading candidates identified in Part 1 are:

  • Lockheed Martin: LMH-1 hybrid airship
  • Hybrid Air Vehicles (HAV): Airlander 10 hybrid airship
  • Aeros Aeroscraft: ML866 / Aeroscraft Gen 2 variable buoyancy airship
  • Volaris: V932 NATAC semi-buoyant airship

These airships will be competing in the worldwide airship market with the leading candidates identified in Part 2, which may enter the market in the same time frame:

  • Flying Whales: LCA60T rigid airship
  • Varialift:  ARH-PT variable buoyancy airship prototype and the larger ARH 50
  • Euro Airship:  Corsair & DGPAtt variable buoyancy airships
  • Solar Ship: 24-meter Caracal light cargo semi-buoyant airship and the Wolverine medium cargo semi-buoyant aircraft
  • Egan Airships:  The PLIMP drone and Model J plane / blimp hybrids

All of these candidates depend on a source of funding to bring their designs to market. 

The early 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 airworthiness certificates will be enough to open a new era in airship transportation. Aviation regulatory agencies need to help reduce risk by eliminating 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.

9. Links to the individual articles

The following links will take you to the 22 individual Modern Airships – Part 1 articles.  Note that the following articles address more than one airship that appeared in the preceding graphic tables:  Aereon, Aeros, Helistats, Hybrid Air Vehicles, Ohio Airships and Voliris.

Conventional airships:

Variable buoyancy, fixed volume airships:

Helistats (airship / helicopter hybrid):

Hybrid, semi-buoyant aircraft:

Hybrid, semi-buoyant airships:

Thermal (hot air) airships:

Modern Airships – Part 3

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 79 individual articles on historic and advanced airship designs. This is Part 3.  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 3 begins with a summary table identifying the airship concepts addressed in this part, and concludes by providing links to 32 individual articles on these airship concepts. A downloadable copy of Part 3 is available here:

If you have any comments or wish to identify errors in this document, 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

August 2019

2. Specific airship concepts in Part 3

The airships described in Part 3 are relatively exotic concepts in comparison to the heavy-lift cargo airships that dominate Parts 1 and 2.  Many of the airship concepts in Part 3 are designed for operation with very low or no carbon emissions.  I’ve grouped these airship concepts based on their applications rather than on their design / type because sometimes those details are difficult to determine when few graphics and limited descriptions are available.  A few of these airships look good as concepts, but may be impossible to build.  Nonetheless, all of these relatively exotic concepts point toward an airship future that will benefit from the great creativity expressed by these designers.

The airship design concepts reviewed in Part 3 are summarized in the following set of tables.  Except for a few sub-scale models, none of these airship concepts have flown.  Links to individual articles on these airships are provided at the end of this document.

3. Links to the individual articles

The following links will take you to 32 individual articles.  Note that the Avalon Airships article addresses all three of their airship design concepts, which are listed separately in the above tables and in the following index.

Cargo & multi-purpose airships

Mass transportation airships:

Flying hotel airships:

Touring airships:

Flying yacht airships:

Remotely-piloted special purpose airship:

Personal airships:

Thermal (hot air) airships:

Other novel designs:

Modern Airships – Part 2

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 79 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 table identifying the airship concepts addressed in this part, and concludes by providing links to 25 individual articles on these airship concepts. A downloadable copy of Part 2 is available here:

The links to the individual articles are at the end of this document.

If you have any comments or wish to identify errors in this document, 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

August 2019

2. Specific airships in Part 2

The airships reviewed in Part 2 are summarized in the following set of tables.  There are many heavy-lift cargo airships in these tables. In addition, there are several solar-powered airships and sub-scale airships that demonstrated novel means of airship propulsion.  Links to the individual articles on these airships are provided at the end of this document.

Among the airships in the above tables, the following full-scale airships have flown:

  • Project Sol’R Nephelios solar-powered airship
  • Solar Ship 20-meter Caracal prototype
  • Solomon Andrews’ Aereon I and II variable buoyancy propulsion airships (in the 1860s)

In addition, the following sub-scale demonstrators have flown:

  • Festo b-IONIC Airfish (demonstration of ionic propulsion)
  • Phoenix and AHAB (demonstrations of variable buoyancy propulsion)

Among the airships in the above tables, several airships are likely to receive their airworthiness certification in the next several years. The leading candidates identified in Part 2 are:

  • Flying Whales: The LCA60T prototype maiden flight is expected to take place in 2021, and the firm appears to have the funding needed to enter full-scale production.
  • Varialift:  The ARH-PT prototype’s first “float test” is expected in 2019.  The first ARH 50 roll out is expected in 2021, with a 24-month certification process before commercial deliveries begin.
  • Euro Airship: Production-ready drawings exist for the Corsair and the larger DGPAtt.  When funding becomes available, they’re ready to go.
  • Solar Ship: The 24-meter Caracal semi-buoyant, inflated wing airship and the larger Wolverine semi-buoyant aircraft are expected to receive Canadian certification, possibly by 2020 – 2021.
  • Egan Airships:  The PLIMP drone and Model J plane / blimp hybrids that have started their FAA certification processes.

These airships will be competing in the worldwide airship market with the leading candidates identified in Part 1, which may enter the market in the same time frame:

  • Lockheed Martin: LMH-1 hybrid airship
  • Hybrid Air Vehicles (HAV): Airlander 10 hybrid airship
  • Aeros Aeroscraft ML866 / Aeroscraft Gen 2: variable buoyancy airship
  • Volaris V932 NATAC: semi-buoyant, inflated wing airship

The early 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 airworthiness certificates will be enough to open a new era in airship transportation. Aviation regulatory agencies need to help reduce risk by eliminating 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.

3. Links to the individual articles

The following links will take you to the 25 individual articles.  Note that the Atlas / Augur RosAeroSystems, Solar Ship, Egan Airships, and variable buoyancy propulsion articles addressed all of the related airship designs, some of which were listed separately in the preceding tables.

Conventional airships:

Variable buoyancy, fixed volume airships:

Variable buoyancy, variable volume airships:

Hybrid, semi-buoyant airships:

Hybrid, solar-powered airships

Plane / blimp hybrids:

Solid-state propulsion airship:

Variable buoyancy propulsion airships:

Riding the Phantom Zephyr

1.  Background

When charged molecules in the air are subjected to an electric field, they are accelerated. When these charged molecules collide with neutral ones, they transfer part of their momentum, leading to air movement known as an “ionic wind.”  This basic process is shown in the following diagram, which depicts a strong electric field between a discharge electrode (left) and a ground electrode (right), and the motion of negative ions toward the ground electrode where they are collected.  The neutral molecules pass through the ground electrode and generate the thrust called the ionic wind.

This post summarizes work that has been done to develop ionic wind propulsion systems for aircraft.  The particular projects summarized are the following:

  • Major Alexander de Seversky’s Ionocraft vertical lifter (1964)
  • The Festo b-IONIC Airfish airship (2005)
  • NASA ionic wind study (2009)
  • The MIT electroaerodynamic (EAD) heaver-than-air, fixed wing aircraft (2018)

2.  Scale model of ion-propelled Ionocraft vertical takeoff lifter flew in 1964

Major Alexander de Seversky developed the design concept for a novel aircraft concept called the “Ionocraft,” which was capable of hovering or moving in any direction at high altitudes by means of ionic discharge. His design for the Ionocraft is described in US Patent 3,130,945, “Ionocraft,” dated 28 April 1964.  You can read this patent here: https://patents.google.com/patent/US3130945A/en

The operating principle of de Seversky’s Ionocraft propulsion system is depicted in the following graphic.

Ion propulsion scheme implemented in the de Seversky Ionocraft. 
Source: Popular Mechanics, August 1964

In 1964, de Seversky built a two-ounce (57 gram) Ionocraft scale model and demonstrated its ability to fly while powered from an external 90 watt power conversion system (30,000 volts at 3 mA), significantly higher that conventional aircraft and helicopters.  This translated into a power-to-weight ratio of about 0.96 hp/pound.  You can watch a short 1964 video of a scale model Ionocraft test flight here: 

Screenshot showing Ionocraft scale model in flight
Screenshot showing ionic wind downdraft under an Ionocraft scale model in flight

De Seversky’s Ionocraft and its test program are described in an article in the August 1964 Popular Mechanics magazine, which is available at the following link:  https://books.google.com/books?id=ROMDAAAAMBAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

Alexander de Seversky’s one-man Ionocraft concept.
Source: Popular Mechanics Archive, August 1964
Alexander de Seversky’s Ionocraft commuter concept.
Source: Popular Mechanics Archive, August 1964
1960s Soviet concept for a passenger carrying Ionocraft.
The Museum of Unnatural Mystery, http://www.unmuseum.org/

In the 1960s, engineers found that Ionocraft technology did not scale up well and they were unable to build a vehicle that could generate enough lift to carry the equipment needed to produce the electricity needed to drive it.

3.  The first free-flying ion-propelled aircraft flew in 2005: the Festo b-IONIC Airfish

The Festo b-IONIC Airfish airship was developed at the Technical University of Berlinwith guidance of the firm Festo AG & Co. KG.  This small, non-rigid airship is notable because, in 2005, it became the first aircraft to fly with a solid state propulsion system.  The neutrally-buoyant Airfish only flew indoors, in a controlled environment, at a very slow speed, but it flew.

Airfish. Source:  Festo AG & Co. KG

Some of the technical characteristics of the Airfish are listed below:

  • Length:  7.5 meters (24.6 ft)
  • Span: 3.0 meters (9.8 ft)
  • Shell diameter: 1.83 meters (6 ft)
  • Helium volume:  9.0 m3(318 ft3)
  • Total weight:  9.04 kg (19.9 lb)
  • Power source in tail: 12 x 1,500 mAh lithium-ion polymer cells (18 Ah total)
  • Power source per wing (two wings): 9 x 3,200 mAh lithium-ion polymer cells (28.8 Ah total)
  • High voltage: 20,000 to 30,000 volts
  • Buoyancy:  9.0 – 9.3 kg (19.8 – 20.5 lb)
  • Total thrust:  8 – 10 grams (0.018 – 0.022 pounds) 
  • Maximum velocity: 0.7 meters/sec (2.5 kph; 1.6 mph)

The b-IONIC Airfish employed two solid state propulsion systems, an electrostatic ionic jet and a plasma ray, which Festo describes as follows:

  • Electrostatic ionic jet:  “At the tail end Airfish uses the classic principle of an electrostatic ionic jet propulsion engine. High-voltage DC-fields (20-30 kV) along thin copper wires tear electrons away from air molecules. The positive ions thus created are then accelerated towards the negatively charged counter electrodes (ring-shaped aluminum foils) at high speeds (300-400 m/s), pulling along additional neutral air molecules. This creates an effective ion stream with speeds of up to 10 m/s.”
  • Plasma-ray:  “The side wings of Airfish are equipped with a new bionic plasma-ray propulsion system, which mimics the wing based stroke principle used by birds, such as penguins, without actually applying movable mechanical parts. As is the case with the natural role model, the plasma-ray system accelerates air in a wavelike pattern while it is moving across the wings.”
Airfish.  Source: Festo AG & Co. KG
Airfish.  Source: Festo AG & Co

The Festo b-IONIC Airfish demonstrated that a solid state propulsion system was possible.  The tests also demonstrated that the solid state propulsion systems also reduced drag, raising the intriguing possibility that it may be possible to significantly reduce drag if an entire vessel could be enclosed in a ionized plasma bubble.You’ll find more information on the Festo b-IONIC Airfish, its solid state propulsion system and implications for drag reduction in the the Festo brochure here: https://www.festo.com/net/SupportPortal/Files/344798/b_IONIC_Airfish_en.pdf

You can watch a 2005 short video on the Festo b-IONIC Airfish flight here:

4.  NASA ionic wind study – 2009

A corona discharge device generates an ionic wind, and thrust, when a high voltage corona discharge is struck between sharply pointed electrodes and larger radius ground electrodes.

In 2009, National Aeronautics & Space Administration (NASA) researchers Jack Wilson, Hugh Perkins and William Thompson conducted a study to examine whether the thrust of corona discharge systems could be scaled to values of interest for aircraft propulsion.  Their results are reported in report NASA/TM-2009-215822, which you’ll find at the following link: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100000021.pdf

Key points of the study included:

  • Different types of high voltage electrodes were tried, including wires, knife-edges, and arrays of pins. A pin array was found to be optimum. 
  • Parametric experiments, and theory, showed that the thrust per unit power could be raised from early values of 5 N/kW to values approaching 50 N/kW, but only by lowering the thrust produced, and raising the voltage applied. 
  • In addition to using DC voltage, pulsed excitation, with and without a DC bias, was examined. The results were inconclusive as to whether this was advantageous. 
  • It was concluded that the use of a corona discharge for aircraft propulsion did not seem very practical.”

5.  The first heavier-than-air, fixed-wing, ion-propelled aircraft flew in 2018

On 21 November 2018, MIT researchers reported successfully flying the world’s first heavier-than-air, fixed-wing, ion-propelled (electroaerodynamic, EAD) aircraft.  You can read the paper by Haofeng Xu, et al., “Flight of an aeroplane with solid-state propulsion,” on the Nature website here: https://www.nature.com/articles/s41586-018-0707-9

The design of the MIT EAD aircraft is shown below:

a, Computer-generated rendering of the EAD airplane. 
b, Photograph of actual EAD airplane (after multiple flight trials).

Some of the technical characteristics of this MIT aircraft are listed below:

  • Wingspan: 4.9 meters (16 ft)
  • Total weight: 2.45 kg (5.4 lb)
  • Power source: powered by 54 x 3.7 volt 150 mAh lithium-ion polymer cells (8.1 Ah total)
  • High voltage: 40,000 volts (+ 20,000 volts / – 20,000 volts)
  • Total thrust: 3.2 N, 326 grams (0.718 pounds) 
  • Maximum velocity: 4.8 meters/sec (17.3 kph; 10.7 mph)

In their paper, the MIT researchers reported:

  • “We performed ten flights with the full-scale experimental aircraft at the MIT Johnson Indoor Track…. Owing to the limited length of the indoor space (60 m), we used a bungeed launch system to accelerate the aircraft from stationary to a steady flight velocity of 5 meters/sec within 5 meters, and performed free flight in the remaining 55 meters of flight space. We also performed ten unpowered glides with the thrusters turned off, in which the airplane flew for less than 10 meters. We used cameras and a computer vision algorithm to track the aircraft position and determine the flight trajectory.”
  • “All flights gained height over the 8–9 second segment of steady flight, which covered a distance of 40–45 meters…. The average physical height gain of all flights was 0.47 meters…. However, for some of the flights, the aircraft velocity decreased during the flight. An adjustment for this loss of kinetic energy…. results in an energy equivalent height gain, which is the height gain that would have been achieved had the velocity remained constant. This was positive for seven of the ten flights, showing that better than steady-level flight had been achieved in those cases.”
  • “In this proof of concept for this method of propulsion, the realized thrust-to-power ratio was 5 N/kW1, which is of the order of conventional airplane propulsion methods such as the jet engine.”  Overall efficiency was estimated to be 2.56%.

The propulsion principles of the MIT EAD aircraft are explained in relation to the following diagram in the November 2018 article by Franck Plouraboué, “Flying With Ionic Wind,” which you can read on the Nature website at the following link:  https://www.nature.com/articles/d41586-018-07411-z

The following diagram and explanatory text are reproduced from that article.

  • In Figure a, above: …an electric field (not shown) is applied to the region surrounding a fine wire called the emitter (shown in cross-section). The field induces electron cascades, whereby free electrons collide with air molecules (not shown in the cascades) and consequently free up more electrons. This process produces charged air molecules in the vicinity of the emitter — a corona discharge. Depending on the electric field, negatively or positively charged molecules drift away (red arrows) from the emitter. These molecules collide with neutral air molecules, generating an ionic wind (black arrows). 
  • In Figure b, above: The aircraft uses a series of emitters and devices called collectors, the longitudinal directions of which are perpendicular to the ionic wind. The flow of charged air molecules occurs mainly along the directions (red arrows) joining emitters and collectors. Consequently, the ionic wind is accelerated (black arrows) predominantly in these regions. 

You can view a short video of the MIT EAD aircraft test flights here:  

6.  The future of ionic propulsion for aerospace applications.

If it can be successfully developed to much larger scales, ionic propulsion offers the potential for aircraft to fly in the atmosphere on a variety of practical missions using only ionized air for propulsion.  Using other ionized fluid media, ionic propulsion could develop into a means to fly directly from the surface of the earth into the vacuum of space and then operate in that environment.In 2006, the Technical University of Berlin’s Airfish project manager, Berkant Göksel, founded the firm Electrofluidsystems Ltd., which in 2012 was rebranded as IB Göksel Electrofluidsystems.  This firm presently is developing a new third generation of plasma-driven airships with highly reduced ozone and nitrogen oxide (NOx) emissions, magneto-plasma actuators for plasma flow control, and the company’s own blended wing type flying wing products.  You’ll find their website here:  https://www.electrofluidsystems.com

Source: Electrofluidsystems TU Berlin
Advanced plasma-driven aircraft concept. Source:  Electrofluidsystems TU Berlin

MIT researchers are developing designs for high-performance aircraft using ionic propulsion.  Theoretically, efficiency improves with speed, with an efficiency of 50% possible at a speed of about 1,000 kph (621 mph).  You can watch a short video on MIT work to develop a Star Trek-like ion drive aircraft here:  

7.  More reading on electrodynamic propulsion for aircraft

General

MIT electroaerodynamic aircraft

Ionocraft lifters

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

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:

https://www.youtube.com/watch?v=jcqPvKfZjac

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:

https://pdfs.semanticscholar.org/8b21/111dee323c13a57079767b4973ce30bc6c24.pdf

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

Paul Allen’s Stratolaunch Aircraft Makes its First Flight, but With an Uncertain Business Plan

Background

The firm Orbital ATK (formerly Orbital Sciences Corporation) was the first to develop a commercial, air-launched rocket capable of placing payloads into Earth orbit.  Initial tests of their modest-size Pegasus launch vehicle were made in 1990 from the NASA B-52 that previously had been used as the “mothership” for the X-15 experimental manned space plane and many other experimental vehicles.

Since 1994, Orbital ATK has been using a specially modified civilian Lockheed L-1011 TriStar, a former airliner renamed Stargazer, as a mothership to carry a Pegasus launch vehicle to high altitude, where the rocket is released to fly a variety of missions, including carrying satellites into orbit.  With a Pegasus XL  as its payload (launch vehicle + satellite), Stargazer is lifting up to 23,130 kg (50,990 pounds) to a launch point at an altitude of about 12.2 km (40,000 feet).

Orbital ATK’s Pegasus XL rocket released from Stargazer.  
Source: NASA / http://mediaarchive.ksc.nasa.gov

You can watch a 2015 video celebrating 25 years of Orbital ATK’s Pegasus air-launched rocket at the following link: https://www.youtube.com/watch?v=0L47cpXTzQU

Paul Allen’s firm Stratolaunch Systems Corporation (https://www.stratolaunch.com) was founded in 2011 to take this air-launch concept to a new level with their giant, twin-fuselage, six-engine Stratolaunch carrier aircraft.  The aircraft has a wingspan of 385 feet (117 m), which is the greatest of any aircraft ever built, a length of 238 feet (72.5 m), and a height of 50 feet (15.2 m) to the top of the vertical tails. The empty weight of the aircraft is about 500,000 pounds (226,796 kg).  It is designed for a maximum takeoff weight of 1,300,000 pounds (589,670 kg), leaving about 550,000 pounds (249,486 kg) for its payload and the balance for fuel and crew.  It will be able to carry multiple launch vehicles on a single mission to a launch point at an altitude of about 35,000 feet (10,700 m).  A mission profile for the Stratolaunch aircraft is shown in the following diagram.

Typical air-launch mission profile. Source: Stratolaunch Systems

Stratolaunch rollout – 2017

Built by Scaled Composites, the Stratolaunch aircraft was unveiled on 31 May 2017 when it was rolled out at the Mojave Air and Space Port in Mojave, CA.  Following is a series of photos from Stratolaunch Systems showing the rollout.

Stratolaunch ground tests – 2017 to 2019

Ground testing of the aircraft systems started after rollout. By mid-September 2017, the first phase of engine testing was completed, with all six Pratt & Whitney PW4000 turbofan engines operating for the first time.  The first low-speed ground tests conducted in December 2017 reached a modest speed of 25 knot (46 kph).  By January 2019, the high-speed taxi tests had reached a speed of about 119 knots (220 kph) with the nose wheel was off the runway, almost ready for lift off. Following is a series of photos from Stratolaunch Systems showing the taxi tests.

Stratolaunch first flight

The Stratolaunch aircraft, named Roc, made an unannounced first flight from the Mojave Air & Space Port on 13 April 2019.  The aircraft stayed aloft for 2.5 hours, reached a peak altitude of 17,000 feet (5,180 m) and a top speed of 189 mph (304 kph). Following is a series of photos from Stratolaunch Systems showing the Stratolaunch aircraft during its first flight.

Stratolaunch posted an impressive short video of the first flight, which you can view here:

Stratolaunch family of launch vehicles: ambitious plans, but subject to change

In August 2018, Stratolaunch announced its ambitious launch vehicle development plans, which included the family of launch vehicles shown in the following graphic:

  • Up to three Pegasus XL launch vehicles from Northrop Grumman Innovation Systems (formerly Orbital ATK) can be carried on a single Stratolaunch flight. Each Pegasus XL is capable of placing up to 370 kg (816 lb) into a low Earth orbit (LEO, 400 km / 249 mile circular orbit).
  • Medium Launch Vehicle (MLV) capable of placing up to 3,400 kg (7,496 lb) into LEO and intended for short satellite integration timelines, affordable launch and flexible launch profiles.  MLV was under development and first flight was planned for 2022.
  • Medium Launch Vehicle – Heavy, which uses three MLV cores in its first stage. That vehicle would be able to place 6,000 kg (13,228 lb) into LEO.  MLV-Heavy was in the early development stage.
  • A fully reusable space plane named Black Ice, initially intended for orbital cargo delivery and return, with a possible follow-on variant for transporting astronauts to and from orbit.  The space plane was a design study.

Stratolaunch was developing a 200,000 pound thrust, high-performance, liquid fuel hydrogen-oxygen rocket engine, known as the “PGA engine”, for use in their family of launch vehicles.  Additive manufacturing was being widely used to enable rapid prototyping, development and manufacturing.   Successful tests of a 100% additive manufactured major subsystem called the hydrogen preburner were conducted in November 2018.

Stratolaunch Systems planned family of launch vehicles announced in August 2018.
Source: Stratolaunch Systems

After Paul Allen’s death on 15 October 2018, the focus of Stratolaunch Corp was greatly revised. On 18 January 2019, the company announced that it was ending work on its own family of launch vehicles and the PGA rocket engine. The firm announced, “We are streamlining operations, focusing on the aircraft and our ability to support a demonstration launch of the Northrop Grumman Pegasus XL air-launch vehicle.”    

You’ll find an article describing Stratolaunch Systems’ frequently changing launch vehicle plans in an article on the SpaceNews website here:

https://spacenews.com/stratolaunch-abandons-launch-vehicle-program/

What is the future for Stratolaunch?

With only the Pegasus XL as a launch vehicle, and Northrop Grumman having their own Stargazer carrier aircraft for the Pegasus XL, the business case for the Stratolaunch aircraft has been greatly weakened.  Air launch certainly offers a great deal of flexibility for launching small satellites. However, it appears that the newest generation of small orbital launch vehicles, like Electron (Rocket Lab, New Zealand) and Prime (Orbix, UK) will be able to offer similar launch services at lower cost.  Electron is operational now, and Prime is expected to enter service in 2021.  

In a cost competitive launch services market, Stratolaunch does not seem to have an advantage with only the Pegasus XL in its launch vehicle inventory.  Hopefully, they have something else up their sleeve that will take advantage of the remarkable capabilities of the Stratolaunch carrier aircraft.

Stratolaunch’s main competition:  The Northrop Grumman Stargazer at the Mojave Air and Space Port in January 2019, available for its next Pegasus XL launch mission.  Source: Author’s photo

Preliminary Design of an Experimental World-Circling Spaceship

The title of this post also is the title of the first RAND report, SM-11827, which was issued on 5 May 1946 when Project RAND still was part of the Douglas Aircraft Company. The basic concept for an oxygen-alcohol fueled multi-stage world-circling spaceship is shown below.

Source: RAND

Source: RAND

Now, more than 70 years later, it’s very interesting to read this report to gain an appreciation of the state of the art of rocketry in the U.S. in 1946, which already was benefiting from German experience with the V-2 and other rocket programs during WW II.

RAND offers the following abstract for SM-11827:

“More than eleven years before the orbiting of Sputnik, history’s first artificial space satellite, Project RAND — then active within Douglas Aircraft Company’s Engineering Division — released its first report: Preliminary Design of an Experimental World-Circling Spaceship (SM-11827), May 2, 1946. Interest in the feasibility of space satellites had surfaced somewhat earlier in a Navy proposal for an interservice space program (March 1946). Major General Curtis E. LeMay, then Deputy Chief of the Air Staff for Research and Development, considered space operations to be an extension of air operations. He tasked Project RAND to undertake a feasibility study of its own with a three-week deadline. The resulting report arrived two days before a critical review of the subject with the Navy. The central argument turns on the feasibility of such a space vehicle from an engineering standpoint, but alongside the curves and tabulations are visionary statements, such as that by Louis Ridenour on the significance of satellites to man’s store of knowledge, and that of Francis Clauser on the possibility of man in space. But the most riveting observation, one that deserves an honored place in the Central Premonitions Registry, was made by one of the contributors, Jimmy Lipp (head of Project RAND’s Missile Division), in a follow-on paper nine months later: ‘Since mastery of the elements is a reliable index of material progress, the nation which first makes significant achievements in space travel will be acknowledged as the world leader in both military and scientific techniques. To visualize the impact on the world, one can imagine the consternation and admiration that would be felt here if the United States were to discover suddenly that some other nation had already put up a successful satellite.’”

You can buy the book from several on-line sellers or directly from RAND. However you also can download the complete report for free in three pdf files that you’ll find on the RAND website at the following link:

https://www.rand.org/pubs/special_memoranda/SM11827.html

 

 

Stratospheric Tourism Coming Soon

On 31 May 1931 Professor Auguste Piccard and Paul Kipfer made the first balloon flight into the stratosphere in a pressurized gondola. These aeronauts reached an altitude of 51,777 ft (15,782 m) above Augsburg, Germany in the balloon named FNRS (Belgian National Foundation for Scientific Research). At that time, a state-of-the-art high-altitude balloon was made of relatively heavy rubberized fabric. Several nations made stratospheric balloon flights in the 1930s, with the U.S. National Geographic Society’s Explorer II setting an altitude record of 72,395 ft (22,065 m) on 11 November 1935.

After World War II, very large, lightweight, polyethylene plastic balloons were developed in the U.S. by Jean Piccard (August Piccard’s twin brother) and Otto Winzen. These balloons were used primarily by the U.S. military to fly payloads to very high altitudes for a variety of research and other projects.

The Office of Naval Research (ONR) launched its first Project Skyhook balloon (a Piccard-Winzen balloon) on 25 September 1947, and launched more than 1,500 Skyhook balloons during the following decade. The first manned flight in a Skyhook balloon occurred in 1949.

The record for the highest unmanned balloon flight was set in 1972 by the Winzen Research Balloon, which achieved a record altitude of 170,000 ft (51,816 m) over Chico, CA.

USAF Project Man High & U.S. Navy Strato-Lab: 1956 – 1961

Manned stratospheric balloon flights became common in the 1950s and early 1960s under the U.S. Air Force’s Man High program and the U.S. Navy’s Strato-Lab program. One goal of these flights was to gather physiological data on humans in pressure suits exposed to near-space conditions at altitudes of about 20 miles (32.2 km) above the Earth. You’ll find an overview of these military programs at the following link:

http://www.space-unit.com/articles/manned_pioneer_flights_in_the_usa.pdf

Three Man High flights were conducted between June 1957 and October 1958. In August 1957, the Man High II balloon flight by Major David Simons reached the highest altitude of the program: 101,516 feet (30,942 m). The rather cramped Man High II gondola is shown in the following diagram.

Man High II gondola. Source: USAF.

The Man High II gondola is on display at the National Museum of the United States Air Force, Dayton, OH. You’ll find details on the Man High II mission at the following link:

http://stratocat.com.ar/fichas-e/1957/CBY-19570819.htm

Five Strato-Lab flights were made between August 1956 and May 1961, with some flights using a pressurized gondola and others an open, unpressurized gondola. The last mission, Strato-Lab High V, carrying Commander Malcolm Ross and scientist Victor Prather in an unpressurized gondola, reached a maximum altitude of 113,740 ft (34,575 meters) on the 4 May 1961. The main objective of this flight was to test the Navy’s Mark IV full-pressure flight suit.

Strato-Lab V open gondola. Source: stratocat.com

See the following link for details on Strato-Lab missions.

http://stratocat.com.ar/artics/stratolab-e.htm

USAF Project Excelsior: 1959 – 60

To study the effects of high-altitude bailout on pilots, the USAF conducted Project Excelsior in 1959 and 1960, with USAF Capt. Joseph Kittinger making all three Excelsior balloon flights. In the Excelsior III flight on 16 August 1960, Capt. Kittinger bailed out from the unpressurized gondola at an altitude of 102,800 feet (31,330 m) and was in free-fall for 4 minutes 36 seconds. Thanks to lessons learned on the previous Excelsior flights, a small drogue stabilized Kittinger’s free-fall, during which he reached a maximum vertical velocity of 614 mph (988 km/h) before slowing to a typical skydiving velocity of 110 – 120 mph (177 – 193 kph) in the lower atmosphere. You’ll find Capt. Kittinger’s personal account of this record parachute jump at the following link:

http://news.nationalgeographic.com/news/2012/10/121008-joseph-kittinger-felix-baumgartner-skydive-science/

Project Stargazer: 1960

Capt. Kittinger and astronomer William White performed 18 hours of astronomical observations from the open gondola of the Stargazer balloon. The flight, conducted on 13 – 14 December 1960, reached a maximum altitude of 82,200 feet (25,100 m).

Red Bull Stratos: 2012

On 14 October 2012, Felix Baumgartner exited the Red Bull Stratos balloon gondola at 128,100 feet (39,045 m) and broke Joe Kittinger’s 52-year old record for the highest parachute jump. Shortly after release, Baumgartner started gyrating uncontrollably due to asymmetric drag in the thin upper atmosphere and no means to stabilize his attitude until reaching denser atmosphere. During his perilous 4 minute 40 second free-fall to an altitude of about 8,200 ft (2,500 m), he went supersonic and reached a maximum vertical velocity of 833.9 mph (1,342.8 kph, Mach 1.263).

You’ll find details on Baumgartner’s mission at the following link:

http://www.redbullstratos.com

Capt. Kittinger was an advisor to the Red Bull Stratos team. The gondola, Felix Baumgartner’s pressure suit and parachute are on display at the Smithsonian Air & Space Museum’s Udvar-Hazy Center in Chantilly, VA.

Red Bull Stratos gondola & pressure suit. Source: Smithsonian

Stratospheric Explorer: 2014

Baumgartner’s record was short-lived, being broken on 14 October 2014 when Alan Eustace jumped from the Stratospheric Explorer (StratEx) balloon at an altitude of 135,899 ft (41,422 meters).  Eustace used a drogue device to help maintain stability during the free-fall, before his main parachute opened. He fell 123,235 ft (37,623 meters) with the drogue and reached a maximum vertical velocity of 822 mph (1,320 km/h); faster than the speed of sound. You can read an interview of Alan Eustace, including his thoughts on stratosphere balloon tourism, at the following link:

http://www.popsci.com/moonshot-man-why-googles-alan-eustace-set-new-free-fall-record

More information of this record-setting parachute jump is at the following link:

http://www.space.com/34725-14-minutes-from-earth-supersonic-skydive.html

World View® Voyager

If you’re not ready to sign up for a passenger rocket flight, and the idea of bailing out of a balloon high in the stratosphere isn’t your cup of tea, then perhaps you’d consider a less stressful flight into the stratosphere in the pressurized gondola of the Voyager passenger balloon being developed by World View Enterprises, Inc. They describe an ascent in the Voyager passenger balloon as follows:

“With World View®, you’ll discover what it’s like to leave the surface of the Earth behind. Every tree, every building, even the mountains themselves become smaller and smaller as you gently and effortlessly rise above. The world becomes a natural collage of magnificent beauty, one you can only appreciate from space. Floating up more than 100,000 feet within the layers of the atmosphere, you will be safely and securely sailing at the very threshold of the heavens, skimming the edge of space for hours. The breathtaking view unfolds before you—our home planet suspended in the deep, beckoning cosmos. Your world view will be forever changed.”

You can view an animated video of such a flight at the following link:

https://vimeo.com/76082638

The following screenshots from this video show the very large balloon and the pressurized Voyager gondola, which is suspended beneath a pre-deployed parafoil parachute connected to the balloon. After reaching maximum altitude, the Voyager balloon will descend until appropriate conditions are met for releasing the parafoil and gondola, which will glide back to a predetermined landing point.

Source for five screenshots, above:  WorldView Enterprises, Inc.

In February 2017, World View opened a large facility at Spaceport Tucson to support its plans for developing and deploying unmanned balloons for a variety of missions as well as Voyager passenger balloons. World View announced plans to a fly a test vehicle named Explorer from Spaceport Tucson in early 2018, with edge-of-space passenger flights by the end of the decade.

For more information on World View Enterprises and the Voyager stratosphere balloon, visit their website at the following link:

http://www.worldview.space/about/#overview

 

 

Protocol for Reporting UFO Sightings

The United States Air Force began investigating unidentified flying objects (UFOs) in the fall of 1947 under a program called Project Sign, which later became Project Grudge, and in January 1952 became Project Blue Book. As you might expect, the USAF developed a reporting protocol for these projects.

Starting in 1951, the succession of Air Force documents that provided UFO reporting guidance is summarized below:

Headquarters USAF Letter AFOIN-C/CC-2

This letter, entitled, “Reporting of Information on Unidentified Flying Objects,” dated 19 December 1951, may be the original guidance document for UFO reporting. So far, I have been unable to find a copy of this document. The Project Blue Book archives contain examples of UFO reports from 1952 citing AFOIN-C/CC-2.

Air Force Letter AFL 200-5

The first reporting protocol I could find was Air Force Letter AFL 200-5, “Unidentified Flying Objects Reporting,” dated 29 April 1952, which was issued on behalf of the Secretary of the USAF by Hoyt S. Vandenberg, Chief of Staff of the USAF.

  • Defines UFOs as, “any airborne object which by performance, aerodynamic characteristics, or unusual features, does not conform to any presently known aircraft or missile type.”
  • UFO reporting is treated as an Intelligence activity (denoted by the 200-series document number)
  • Provides brief guidance on report content, which was to be submitted on AF Form 112, “Air Intelligence Information Report,” and not classified higher than RESTRICTED.
  • The local Commanding Officer is responsible for forwarding FLYOBRPTS to the appropriate agencies. FLYOBRPT is an acronym for FLYing OBject RePorT.
  • Responsibility for investigating UFOs was assigned to the Air Technical Intelligence Center (ATIC) at Wright Patterson Air Force Base, Ohio. ATIC was a field activity of the Directorate of Intelligence in USAF Headquarters.
  • AFL 200-5 does not indicate that it superseded any prior USAF UFO reporting guidance document, but it is likely that it replaced USAF letter AFOIN-C/CC-2, dated 19 December 1951.

Download AFL 200-5 at the following link:

http://www.cufon.org/cufon/AFL_200-5.pdf

How to Make FLYOBRPTs

In 1953, the AITC issued “How to Make FLYOBRPTs,” dated 25 July 1953, to help improve reporting required by AFL 200-5.

Figure 1 from How to Make a FLYOBRPT

Source: USAF

This guidance document provides an interesting narrative about UFOs through 1953, explains how to collect information on a UFO sighting, including interacting with the public during the investigation, and how to complete a FLYOBRPT using four detailed data collection forms.

  • Ground Observer’s Information Sheet (9 pages)
  • Electronics Data Sheet (radar) (5 pages)
  • Airborne Observer’s Data Sheet (9 pages) and,
  • Supporting Data form (8 pages)

This report showed that the USAF had a sense of humor about UFO reporting.

Figure 2 from How to Make a FLYOBRPTSource: USAF

Download “How to Make FLYOBRPTs” at the following link:

http://www.cufon.org/cufon/FLYOBRPT.pdf

Air Force Regulation AFR 200-2

In 1953, the Secretary of the Air Force, Harold E. Talbott, issued the original Air Force Regulation AFR 200-2, “Unidentified Flying Objects Reporting”, dated 26 August 1953.

  • Superseded AFL 200-5, dated 29 April 1952
  • Defines procedures for reporting UFOs and restrictions on public discussion by Air Force personnel
  • Change 200-2A was issued on 2 November 1953
  • Between 1954 and 1962, the USAF issued several subsequent versions of AFR 200-2, as listed below.

AFR 200-2, “Unidentified Flying Objects Reporting (Short Title: FLYOBRPT)”, dated 12 August 1954.

  • Superseded AFR 200-2 dated 26 August 1953 and Change 200-2A
  • Identifies the USAF interest in UFOs as follows: “Air Force interest in unidentified flying objects is twofold: First as a possible threat to the security of the United States and its forces, and secondly, to determine technical aspects involved.”
  • Defines an expected report format that is less comprehensive than the guidance in “How to Make FLYOBRPTs.”
  • Clarifies that Headquarters USAF will release summaries of evaluated data to the public. Also notes that it is permissible to respond to local inquiries when the object is positively identified as a “familiar object” (not a UFO). In other cases, the only response is that ATIC will analyze the data.
  • Download this version of AFR 200-2 at the following link:

http://www.cufon.org/cufon/afr200-2.htm

AFR 200-2, “Unidentified Flying Objects (UFO),” dated 5 February 1958

  • Supersedes the version dated 12 August 1954
  • Broadens the USAF interest in UFOs: “First as a possible threat to the security of the United States and its forces; second, to determine the technical or scientific characteristics of any such UFOs; third, to explain or identify all UFO sightings…”
  • Updates report formats and provides additional guidance on reporting
  • Download this version from the CIA website at the following link:

https://www.cia.gov/library/readingroom/docs/CIA-RDP81R00560R000100040072-9.pdf

AFR 200-2, “Unidentified Flying Objects (UFO),” dated 14 September 1959

  • Supersedes the version dated 5 February 1958

AFR 200-2, “Unidentified Flying Objects (UFO),” dated 20 July 1962

  • Supersedes the version dated 14 September 1959
  • Superseded by AFR 80-17

Air Force Regulation AFR 80-17

In 1966, the USAF issued AFR 80-17, “Unidentified Flying Objects (UFO),” dated 19 September 1966

  • Supersedes AFR 200-2 dated 20 July 1962.
  • Two changes were issued:
    • AFR 80-17, Change 80-17A, dated 8 November 1966
    • AFR 80-17, Change 1, dated 26 October 1968, superseded AFR 80-17A, 8 November 1966
  • No longer considers UFO reporting as an intelligence activity, as denoted by the 80-series number assigned to the AFR
  • Places UFO reporting under the Research and Development Command. This is consistent with recasting ATIC into the Foreign Technology Division (FTD) of the Air Force Systems Command at Wright-Patterson AFB.
  • Broadly redefines UFO as “any aerial phenomenon which is unknown or appears out of the ordinary to the observer.”
  • Orders all Air Force bases to provide an investigative capability
  • Change 80-17A assigned University of Colorado to conduct an independent scientific investigation of UFOs. Physicist Edward U. Condon would direct this work.

Download AFR 80-17, with change 80-17A and change 1 here:

http://www.cufon.org/cufon/afr80-17.htm

Project Blue Book’s final report

In late October 1968, the University of Colorado’s final report was completed and submitted for review by a panel of the National Academy of Sciences. The panel approved of the methodology and concurred with Edward Condon’s conclusion:

“That nothing has come from the study of UFOs in the past 21 years that has added to scientific knowledge. Careful consideration of the record as it is available to us leads us to conclude that further extensive study of UFOs probably cannot be justified in the expectation that science will be advanced thereby.”

In January 1969, a 965-page paperback version of the report was published under the title, “Scientific Study of Unidentified Flying Objects.”

On 17 December 1969, Air Force Secretary Robert C. Seamans, Jr., announced the termination of Project Blue Book.

Additional resources

You’ll find a good history by of the U.S. Air Force UFO programs written by Thomas Tulien at the following link:

http://sohp.us/history-of-the-usaf-ufo-programs/8-turning-point.php

 

 

 

The Mysterious Case of the Vanishing Electronics, and More

Announced on 29 January 2013, DARPA is conducting an intriguing program known as VAPR:

“The Vanishing Programmable Resources (VAPR) program seeks electronic systems capable of physically disappearing in a controlled, triggerable manner. These transient electronics should have performance comparable to commercial-off-the-shelf electronics, but with limited device persistence that can be programmed, adjusted in real-time, triggered, and/or be sensitive to the deployment environment.

VAPR aims to enable transient electronics as a deployable technology. To achieve this goal, researchers are pursuing new concepts and capabilities to enable the materials, components, integration and manufacturing that could together realize this new class of electronics.”

VAPR has been referred to as “Snapchat for hardware”. There’s more information on the VAPR program on the DARPA website at the following link:

http://www.darpa.mil/program/vanishing-programmable-resources

Here are a few of the announced results of the VAPR program.

Disintegrating electronics

In December 2013, DARPA awarded a $2.5 million VAPR contract to the Honeywell Aerospace Microelectronics & Precision Sensors segment in Plymouth, MN for transient electronics.

In February 2014, IBM was awarded a $3.4 million VAPR contract to develop a radio-frequency based trigger to shatter a thin glass coating: “IBM plans is to utilize the property of strained glass substrates to shatter as the driving force to reduce attached CMOS chips into …. powder.” Read more at the following link:

http://www.zdnet.com/article/ibm-lands-deal-to-make-darpas-self-destructing-vapr-ware/

Also in February 2014, DARPA awarded a $2.1 million VAPR contract to PARC, a Xerox company. In September 2015, PARC demonstrated an electronic chip built on “strained” Corning Gorilla Glass that will shatter within 10 seconds when remotely triggered. The “strained” glass is susceptible to heat. On command, a resistor heats the glass, causing it to shatter and destroy the embedded electronics. This transience technology is referred to as: Disintegration Upon Stress-release Trigger, or DUST. Read more on PARC’s demonstration and see a short video at the following link:

http://spectrum.ieee.org/tech-talk/computing/hardware/us-militarys-chip-self-destructs-on-command

Disintegrating power source

In December 2013, USA Today reported that DARPA awarded a $4.7 million VAPR contract to SRI International, “to develop a transient power supply that, when triggered, becomes unobservable to the human eye.” The power source is the SPECTRE (Stressed Pillar-Engineered CMOS Technology Readied for Evanescence) silicon-air battery. Details are at the following link:

http://www.usatoday.com/story/nation/2013/12/27/vanishing-silicon-air-battery-darpa/4222327/

On 12 August 2016, the website Science Friday reported that Iowa State scientists have successfully developed a transient lithium-ion battery:

“They’ve developed the first self-destructing, lithium-ion battery capable of delivering 2.5 volts—enough to power a desktop calculator for about 15 minutes. The battery’s polyvinyl alcohol-based polymer casing dissolves in 30 minutes when dropped in water, and its nanoparticles disperse. “

You can read the complete post at:

http://www.sciencefriday.com/segments/this-battery-will-self-destruct-in-30-minutes/

ICARUS (Inbound, Controlled, Air-Releasable, Unrecoverable Systems)

On 9 October 2015, DARPA issued “a call for disappearing delivery vehicles,” which you can read at the following link:

http://www.darpa.mil/news-events/2015-10-09

In this announcement DARPA stated:

“Our partners in the VAPR program are developing a lot of structurally sound transient materials whose mechanical properties have exceeded our expectations,” said VAPR and ICARUS program manager Troy Olsson. Among the most eye-widening of these ephemeral materials so far have been small polymer panels that sublimate directly from a solid phase to a gas phase, and electronics-bearing glass strips with high-stress inner anatomies that can be readily triggered to shatter into ultra-fine particles after use. A goal of the VAPR program is electronics made of materials that can be made to vanish if they get left behind after battle, to prevent their retrieval by adversaries.”

With the progress made in VAPR, it became plausible to imagine building larger, more robust structures using these materials for an even wider array of applications. And that led to the question, ‘What sorts of things would be even more useful if they disappeared right after we used them?’”

This is how DARPA conceived the ICARUS single-use drone program described in October 2015 in Broad Area Announcement DARPA-BAA-16-03. The goal of this $8 million, 26-month DARPA program is to develop small drones with the following attributes

  • One-way, autonomous mission
  • 3 meter (9.8 feet) maximum span
  • Disintegrate in 4-hours after payload delivery, or within 30 minutes of exposure to sunlight
  • Fly a lateral distance of 150 km (93 miles) when released from an altitude of 35,000 feet (6.6 miles)
  • Navigate to and deliver various payloads up to 3 pounds (1.36 kg) within 10 meters (31 feet) of a GPS-designated target

The ICARUS mission profile is shown below.

ICARUS mission profileICARUS mission. Source: DARPA-BAA-16-03

More information on ICARUS is available on the DARPA website at:

http://www.darpa.mil/program/inbound-controlled-air-reasonable-unrecoverable-systems

On 14 June 2016, Military & Aerospace reported that two ICARUS contracts had been awarded:

  • PARC (Palo Alto, CA): $2.3 million Phase 1 + $1.9 million Phase 2 option
  • DZYNE Technologies, Inc. (Fairfax, VA): $2.9 million Phase 1 + $3.2 million Phase 2 option

You can watch a short video describing the ICARUS competition at the following link:

https://www.youtube.com/watch?v=i2U1UTDqZbQ

The firm Otherlab (https://otherlab.com) has been involved with several DARPA projects in recent years. While I haven’t seen a DARPA announcement that Otherlab is a funded ICARUS contractor, a recent post by April Glaser on the recode website indicates that the Otherlab has developed a one-way, cardboard glider capable of delivering a small cargo to a precise target.

“When transporting vaccines or other medical supplies, the more you can pack onto the drone, the more relief you can supply,” said Star Simpson, an aeronautics research engineer at Otherlab, the group that’s building the new paper drone. If you don’t haul batteries for a return trip, you can pack more onto the drone, says Simpson.

The autonomous disposable paper drone flies like a glider, meaning it has no motor on board. It does have a small computer, as well as sensors that are programed to adjust the aircraft’s control surfaces, like on its wings or rudder, that determine where the aircraft will travel and land.”

 Otherlab_SkyMachines_APSARA.0Sky machines. Source: Otherworld

Read the complete post on the Otherlab glider on the recode website at the following link:

http://www.recode.net/2017/1/12/14245816/disposable-drones-paper-darpa-save-your-life-otherlab

The future

The general utility of vanishing electronics, power sources and delivery vehicles is clear in the context of military applications. It will be interesting to watch the future development and deployment of integrated systems using these vanishing resources.

The use of autonomous, air-releasable, one-way delivery vehicles (vanishing or not) also should have civilian applications for special situations such as emergency response in hazardous or inaccessible areas.