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At least 19 records

Recent researches in airship construction III : a new type of nonrigid airship

The author describes experiments in designing nonrigid airships. A nonrigid airship of 32,000 cubic meters, the PL 27 withstood all stresses with 20 kg/m(exp 2) hull pressure during its life of two years. The moment of resistance is known, as also the stresses in the envelope for the given hull pressure. The mean internal pressure necessary to give the airship the requisite rigidity and to prevent buckling was also investigated.

AIRSHIPS - CONSTRUCTION↗

The Present Status of Airship Construction, Especially of Airship-framing Construction

This work proposes to sketch, in broad outline, the status of airship construction in the various countries, at a time when commerce over great distances might be finally opened up to the airship through the performances of the "Graf Zeppelin." After a short historical review, a survey of the most important rigid and semirigid airships built since 1925, their differences and special problems, is made. In more detailed treatment, the framing construction of the more recent rigid airships and some especially interesting structural questions are investigated.

Ebner, Hans↗

Recent researches in airship construction I : forces of flow on a moving airship and the effect of the control surfaces

The problems as to how an airship can best be stabilized and steered and to what stresses it is subjected in the air, are so important as to determine in large measure the future development of airships much more than formerly when velocities of 30-35 meters (98-115 feet) per second were not known and the effects of the air flow were not so great.

CONTROL SURFACES, AIRSHIPS↗

Feasibility study of modern airships, phase 2. Volume 1: Heavy lift airship vehicle. Book 1: Overall study results

A Heavy Lift Airship combining buoyant lift derived from a conventional helium-filled non-rigid airship hull with propulsive lift derived from conventional helicopter rotors was investigated. The buoyant lift essentially offsets the empty weight of the vehicle; thus the rotor thrust is available for useful load and to maneuver and control the vehicle. Such a vehicle is capable of providing a quantum increase in current vertical lifting capability. Certain critical deficiencies of past airships are significantly minimized or eliminated.

Source record↗

Recent researches in airship construction II : bending stresses on an airship in flight

The first part of this report shows the differences between commercial and war airships and then goes on to show how some of the problems were solved. Their thorough investigations of these problems finally enabled the Schutte-Lanz Company to construct bulkhead diagrams for determining the buoyancy of airships, by means of which the size of each cell was established. These diagrams were derived from bulkhead diagrams employed in ship designing and are used in a similar manner.

AIRSHIPS - STRESSES, BENDING↗

Report on the 2011 and 2012 NASA Ames Research Center (ARC) / Alaska State Cargo Airship Workshops

This presentation will summarize the Cargo Airships for Northern Operations workshop that was held August 24-25, 2011. This workshop co-sponsored by NASA ARC and the Alaska State Department of Transportation was initiated by interest from Alaska Lt. Governor Mead Treadwell for assistance in investigating the potential benefits of proposed cargo airships for the Alaskan economy and societal needs. The workshop provided a brief background on the technology and operational aspects of conventional airships and hybrids followed by presentations on issues affecting cargo airship operations such as weather management, insurance, regulations, crew duty/rest rules, and available support infrastructures. Speakers representing potential cargo airship users from Alaskan State and commercial organizations presented the needs they felt could be met by cargo airship services. Presenters from Canadian private and military interests also detailed applications and missions that cargo airships could provide to remote regions of Canada. Cost drivers of cargo airship operations were also addressed and tools for modeling and analyzing operational factors and costs affecting cargo airship operations were discussed. Four breakout sessions were held which allowed workshop participants to contribute inputs to four topic areas: Business Approaches and Strategies (financing incentives public/private partnerships etc) for Airship Development and Operation, Design, Development, Production Challenges, and Possible Solutions, Regulatory, Certification, Legal, and Insurance Issues, and Operational Issues, Customer Requirements, and Airship Requirements. A follow on to the 2011 cargo airship workshop is being planned for July 31 August 2, 2012. A status update on this second workshop will also be presented.

Hochstettler, Ronald↗

Heated-Atmosphere Airship for the Titan Environment: Thermal Analysis

Future exploration of Saturn's moon Titan can be carried out by airships. Several lighter-than-atmosphere gas airships and passive drifting heated-atmosphere balloon designs have been studied, but a heated-atmosphere airship could combine the best characteristics of both. This work analyses the thermal design of such a heated-atmosphere vehicle, and compares the result with a lighter-than-atmosphere (hydrogen) airship design. A design tool was created to enable iteration through different design parameters of a heated-atmosphere airship (diameter, number of layers, and insulating gas pocket thicknesses) and evaluate the feasibility of the resulting airship. A baseline heated-atmosphere airship was designed to have a diameter of 6 m (outer diameter of 6.2 m), three-layers of material, and an insulating gas pocket thickness of 0.05 m between each layer. The heated-atmosphere airship has a mass of 161.9 kg. A similar mission making use of a hydrogen-filled airship would require a diameter of 4.3 m and a mass of about 200 kg. For a long-duration mission, the heated-atmosphere airship appears better suited. However, for a mission lifetime under 180 days, the less complex hydrogen airship would likely be a better option.

Heller, R. S.↗

Cargo transportation by airships: A systems study

A systems engineering study of a lighter than air airship transportation system was conducted. The feasibility of the use of airships in hauling cargo was demonstrated. Social, legal, environmental and political factors were considered as well as the technical factors necessary to design an effective airship transportation system. In order to accomplish an effective airship transportation program two phases of implementation were recommended. Phase I would involve a fleet of rigid airships of 3.5 million cubic feet displacement capable of carrying 25 tons of cargo internal to the helium-filled gas bag. The Phase I fleet would demonstrate the economic and technical feasibility of modern-day airships while providing a training capability for the construction and operation of larger airships. The Phase II portion would be a fleet of rigid airships of 12 million cubic feet displacement capable of carrying a cargo of 100 tons a distance of 2,000 miles at a cruising speed of 60 mph. An economic analysis is given for a variety of missions for both Phase I and Phase II airships.

Huang, C. J.↗

On the Development of Parameterized Linear Analytical Longitudinal Airship Models

In order to explore Titan, a moon of Saturn, airships must be able to traverse the atmosphere autonomously. To achieve this, an accurate model and accurate control of the vehicle must be developed so that it is understood how the airship will react to specific sets of control inputs. This paper explains how longitudinal aircraft stability derivatives can be used with airship parameters to create a linear model of the airship solely by combining geometric and aerodynamic airship data. This method does not require system identification of the vehicle. All of the required data can be derived from computational fluid dynamics and wind tunnel testing. This alternate method of developing dynamic airship models will reduce time and cost. Results are compared to other stable airship dynamic models to validate the methods. Future work will address a lateral airship model using the same methods.

aerobot↗

Feasibility study of modern airships. Phase 2: Executive summary

A feasibility study of modern airships has been completed. Three promising modern airship systems' concepts and their associated missions were studied; (1) a heavy-lift airship, employing a non-rigid hull and a significant amount of rotor lift, used for short-range transport and positioning of heavy military and civil payloads, (2) a VTOL (vertical take-off and landing), metalclad, partially buoyant airship used as a short-haul commercial transport; and (3) a class of fully-buoyant airships used for long-endurance Navy missions. The heavy-lift airship concept offers a substantial increase in vertical lift capability over existing systems and is projected to have lower total operating costs per ton-mile. The VTOL airship transport concept appears to be economically competitive with other VTOL aircraft concepts but can attain significantly lower noise levels. The fully-buoyant airship concept can provide an airborne platform with long endurance that satisfies many Navy mission requirements.

Source record↗

Parameterized Linear Longitudinal Airship Model

A parameterized linear mathematical model of the longitudinal dynamics of an airship is undergoing development. This model is intended to be used in designing control systems for future airships that would operate in the atmospheres of Earth and remote planets. Heretofore, the development of linearized models of the longitudinal dynamics of airships has been costly in that it has been necessary to perform extensive flight testing and to use system-identification techniques to construct models that fit the flight-test data. The present model is a generic one that can be relatively easily specialized to approximate the dynamics of specific airships at specific operating points, without need for further system identification, and with significantly less flight testing. The approach taken in the present development is to merge the linearized dynamical equations of an airship with techniques for estimation of aircraft stability derivatives, and to thereby make it possible to construct a linearized dynamical model of the longitudinal dynamics of a specific airship from geometric and aerodynamic data pertaining to that airship. (It is also planned to develop a model of the lateral dynamics by use of the same methods.) All of the aerodynamic data needed to construct the model of a specific airship can be obtained from wind-tunnel testing and computational fluid dynamics

Kulczycki, Eric↗

Radioisotope Stirling Engine Powered Airship for Atmospheric and Surface Exploration of Titan

The feasibility of an advanced Stirling radioisotope generator (ASRG) powered airship for the near surface exploration of Titan was evaluated. The analysis did not consider the complete mission only the operation of the airship within the atmosphere of Titan. The baseline airship utilized two ASRG systems with a total of four general-purpose heat source (GPHS) blocks. Hydrogen gas was used to provide lift. The ASRG systems, airship electronics and controls and the science payload were contained in a payload enclosure. This enclosure was separated into two sections, one for the ASRG systems and the other for the electronics and payload. Each section operated at atmospheric pressure but at different temperatures. The propulsion system consisted of an electric motor driving a propeller. An analysis was set up to size the airship that could operate near the surface of Titan based on the available power from the ASRGs. The atmospheric conditions on Titan were modeled and used in the analysis. The analysis was an iterative process between sizing the airship to carry a specified payload and the power required to operate the electronics, payload and cooling system as well as provide power to the propulsion system to overcome the drag on the airship. A baseline configuration was determined that could meet the power requirements and operate near the Titan surface. From this baseline design additional trades were made to see how other factors affected the design such as the flight altitude and payload mass and volume.

Titan↗

Feasibility of modern airships - Design definition and performance of selected concepts

Three promising modern airship system concepts and their associated missions were studied: (1) a heavy-lift airship, employing a nonrigid hull and a significant amount of rotor lift, used for short-range transporting and positioning of heavy military and civil payloads; (2) a VTOL (vertical take-off and landing), metal-clad, partially buoyant airship used as a short-haul commercial transport; (3) a fully-buoyant airship used for long-endurance Navy missions. The heavy-lift airship concept offers a dramatic increase in vertical lift capability over existing systems at significantly lower costs per ton-mile. The VTOL airship transport concept appears to be economically competititve with other VTOL aircraft concepts but can attain significantly lower noise levels. The fully-buoyant airship concept can provide an airborne platform with long endurance that satisfies many Navy mission requirements.

Huston, R. R.↗

High Altitude Long Endurance UAV Analysis Model Development and Application Study Comparing Solar Powered Airplane and Airship Station-Keeping Capabilities

There have been ongoing efforts in the Aeronautics Systems Analysis Branch at NASA Langley Research Center to develop a suite of integrated physics-based computational utilities suitable for modeling and analyzing extended-duration missions carried out using solar powered aircraft. From these efforts, SolFlyte has emerged as a state-of-the-art vehicle analysis and mission simulation tool capable of modeling both heavier-than-air (HTA) and lighter-than-air (LTA) vehicle concepts. This study compares solar powered airplane and airship station-keeping capability during a variety of high altitude missions, using SolFlyte as the primary analysis component. Three Unmanned Aerial Vehicle (UAV) concepts were designed for this study: an airplane (Operating Empty Weight (OEW) = 3285 kilograms, span = 127 meters, array area = 450 square meters), a small airship (OEW = 3790 kilograms, length = 115 meters, array area = 570 square meters), and a large airship (OEW = 6250 kilograms, length = 135 meters, array area = 1080 square meters). All the vehicles were sized for payload weight and power requirements of 454 kilograms and 5 kilowatts, respectively. Seven mission sites distributed throughout the United States were selected to provide a basis for assessing the vehicle energy budgets and site-persistent operational availability. Seasonal, 30-day duration missions were simulated at each of the sites during March, June, September, and December; one-year duration missions were simulated at three of the sites. Atmospheric conditions during the simulated missions were correlated to National Climatic Data Center (NCDC) historical data measurements at each mission site, at four flight levels. Unique features of the SolFlyte model are described, including methods for calculating recoverable and energy-optimal flight trajectories and the effects of shadows on solar energy collection. Results of this study indicate that: 1) the airplane concept attained longer periods of on-site capability than either airship concept, and 2) the airship concepts can attain higher levels of energy collection and storage than the airplane concept; however, attaining these energy benefits requires adverse design trades of reduced performance (small airship) or excessive solar array area (large airship).

Ozoroski, Thomas A.↗

Airship Industry Study

In April, 2015 NASA Ames Research Center conducted a study of the airship industry. The project called for a report that would describe airship concepts proposed or projects initiated, airship performance or capability targets, and the missions these activities were addressing. It would detail the principal technical features of these airships; the proposed value/advantages of the features, notional concepts of operation, and challenges associated with the vehicles. Also investigated would be the current status and near-term prospects of these airship development activities, whether they are active or, if curtailed the circumstances and possible reasons for that conclusion including technical, business, or other mitigating factors. For the most active programs an assessment would be conducted to identify the resources or activities required for airships to advance to series construction and operational deployment. The study would also identify impediments to these developments and deployments, with recommendations provided to address existing issues in the airship industry today.

Hochstetler, Ron↗

Airship Industry Study

There is an ongoing Government interest in the potential of airships for cargo transport; Conducting vertical or near-vertical airlift of heavy, outsized freight with little or no ground infrastructure is an attractive cargo transport option. USTRANSCOM wanted to understand the principal issues that are holding back commercial development of airship transports. NASA Ames Research Center was commissioned by USTRANSCOM to study the airship industry’s ability to design, develop, and operate cargo airships. Principal study objectives were to identify: (1) Current and near term state of the cargo airship industry; (2) Roadblocks hindering cargo airship development; (3) Steps needed to remove impediments to cargo airship deployment.

Hochstetler, Ron↗

Evacuated Airship for Mars Missions: NIAC Phase I, 2017

An evacuated or vacuum airship relies on the same principle of buoyancy used by standard balloons. However, unlike a balloon which uses a lighter than air gas to displace air and provide lift, the vacuum airship leverages a rigid structure to maintain a vacuum and displace air, thereby providing buoyancy. This method is similar to how a ship uses a rigid structure to displace water and fill the space with air; an evacuated airship uses the same mechanism, except air is displaced and the space remains vacant. Using this method, the evacuated airship is capable of utilizing the full potential of the displaced mass of air, which has interesting implications in the Martian atmosphere. Unlike other aerial vehicles, which are at a disadvantage in Martian atmospheric conditions, the evacuated airship benefits from the Martian atmosphere by virtue of the temperature and molecular composition. As a result, the evacuated airship offers an unprecedented payload capacity and, if implemented, may be used to transport current and future scientific instruments, other vehicles, rovers, and possibly even human habitations. A standard dirigible or balloon for Mars would have a severely limited span of operation and a very narrow field of study, nearly exclusively the atmosphere, but a vacuum airship can be used as a long term tool for many different missions: transportation, ground study, communications, atmospheric study, etcetera, thereby making it a far more economically sensible choice

Clarke, John-Paul↗