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General Disclaimer One or more of the Following Statements may affect this Document This document has been reproduced from the best copy furnished by the organizational source. It is being released in the interest of making available as much information as possible. This document may contain data, which exceeds the sheet parameters. It was furnished in this condition by the organizational source and is the best copy available. This document may contain tone-on-tone or color graphs, charts and/or pictures, which have been reproduced in black and white. This document is paginated as submitted by the original source. Portions of this document are not fully legible due to the historical nature of some of the material. However, it is the best reproduction available from the original submission. Produced by the NASA Center for Aerospace Information (CASI) N -^ q ^ `76 7 (NA6A-TK b4-744) cuiRLNT UEVELUICHENTS i,.L';.t TER IRAN Alit )Yb'ltKS Wllti011a A+L.L'Uttcltlt]C:ca 3tt :ii'uC c Add l.11il ;tL'dt].bI1) ^J c: SC: r, 0^n ux^c]^'.`^^ HC A0z/ril At? l ^t\, ]] ] ] CURRENT DEVELOPMENTS LIGHTER THAN AI R SYSTEMS UNITED NATIONS INDUSTRIAL DEVELOPMENT ORGANIZATION CONFERENCE ON LTA SYSTEMS TECHNOLOGY FOR ire-r,- nr nr1 r_ t nn r klr rn11AITD Y CC THE Bti NEE t ur DEVE OP NG W1 1-1 1,1 1 n At VIENNA, AUSTRIA 19-22 OCTOBER, 1981 NORMAN Js MAYER aq^^o PROGRAM MANAGER AND CONSULTA`y/ VA SYSTEMS ii NATIONAL AERONAUT,ICG AND SPACE ADMINISTRATION WASHINGTON, D,C, r l .r 1 CUIlUNT LTA TECHNOLOGY DEVELOPMENTS Norman J, Mayer NASA He adqunrtesrs Washington, D.C. &12rack Lighter-than-air aircraft '%LTA) Transportation in nations of the third developments and research in the United world constitutes a great potential for States and other countries are reviewed. advanced aircraft development which could The emphasis in the U.S, is on VTOL air- provides capability to bypass some of the ships capable of heavy lift, and on long evolutionary development of surface infra- endurance types for coastal maritime pa- structure which is often non-existent and tiol.Design concepts include hybrids difficult and expensive to develop. which combine heavier-than-air and LTA components and characteristics. Research A further incentive is produced by the programs are concentrated on acrodynamica, increased awareness of all nations to con- flight dynamic.;. irtod control of hybrid serve marine resources with the consequent types. establishment of extensive off-shore zones of protection which require new surveill- ance capability. 111-t., 12.91 t an These now applications have created In the interval between the termina- requirements for airships with character- tion of U.S. Navy airship operations in istics considerably changed as compared to 1962, to about: the middle of the 1970 past designs. These include VTOL capa- decade, the field of lighter-than-air bility under a variety of conditions, long aircraft (LTA) engineering and develop- period hovering, and in some cases higher ment was in a dormant state. The only con- speeds. Such capabilities may not be tinuity during that period was provided by available without the combining of LTA and flight operations with modified World War HTA (heavier-than-air aircraft) features. 11 type training airships by private firms These hybrid concepts will require the in the U.S. and West Germany. development of basic aerodynamic data, better understanding of their flight dynamics, and other new technology. A renaissance of sorts is now occur- iing in which there is world-wide inter- in the following descriptions of est in LTA, evidenced by several 4lovern- current developments, the various aspects ment and privately sponsored studies and of this relationship between now tech- some actual aircraft development. Several nology and aircraft developments will be stimuli have served to create this new emphasized. In this review, various air- attention to an old subject. perhaps the ship types will be described using an es- most important is the potential for new tablished method of referring to their transport capability in a world of chan- structural systems. This method has been ging requirements. These have emanated used with classical airships, as shown from the increasing demands ror heavy- on the left side of Figure 1, but it can lift caused by development of onergy re- also be applied to the newer configura- lated resources in remote areab, harves- tions shown on the right. ting of timber from relatively i.nacessi- M e locations, and by grov , th associated with industrial development. current Developments A second stimulus is the need for Aircraft Developments gvvater transport efficiency through elimination of inter-modal operations, United States - Two major programs, reduced terminal time, and higher fuel focused on different objectives are economy. Such demands in the past led to currently underway. One is the develop- Lbe development of containerized cargoes ment of heavy-lift hybrid airships and and new surface ship development - point- the other is the evaluation of airships ing the way to aerial systems to handle for maritime surveillance. larder sized payloads. Interest in the heavy-lift application was generated around a concept by Frank Piasecki of the Piasecki Aircraft Corp. for combining helicopters and aerostat ORIGINAL PACC 615 OF POcR QUALM TYPES OF LIGHTER•THAWAIR AIRCRAF=T AEROSTATS HYBRIDS BALLOONS "; •^ FREE TETHERED LENTICULAR RIGID ^RIGID ^l" lsoLES SEMI-RIGID AIRSHIPS PRESSURE NON-RIGID m HEAVY-LIFT NON-RIGID METALCLAD rig. 1 2 t` ORICINAL Or voml ^^RI^^.E hulls, tea obtain large vc.; t reveal lift capa- could be compatible: with Coast Guard opera- bility beyond preoent helicopter capaci- tions and would show improved capability ties up to an order of magnitude increase. over certain air and surface units now in This concept appeared to be a fortuitous use. A comparative plot is shown in Fig, 4. solution to a current military problem of For the cases soleeti.d, it was determined off-loading cargo vessels in parts where that airships could cowl-leto from 80-100 facilities do not exist or have been des- percent of the missions at oost.s equal to troyed. Various hybrid types and oombina- the HC-130 airplane and at 50-60 percent tions were studs ,.d by the Goodyear Aero- of the cost of ship operations. In 1980, space Corp. us•oor NASA sponsorship (Ref. 1) NASA entered into a joint agreement with (and lat°ot, independently). The most recent the Coast Guard to also assist in the proposed Goodyear configuration includes assessment of airships and to develop rotors and drive components modified from necessary related technology. Current R&D current helicopters, forward and reverse plans call for the procurement and opera- propellers for horizontal propulsion and a tion of an airship to engage in various 75050 m 3 envelope with a payload of Coast Guard missions. The extent of mission 68 tonnes. (Fig. 2) operation would be limited by the size' and performance of the airship which in all Although an operational requirement likelihood will be of smaller scale than was written by the Navy for, a heavy-lift one required for full mission operation. hybrid (Ref. 2), no program for develop- The flight program would include both mcnt was authorized. NASA has continued to operations with and independent from sur- explore the dynamics and control character- face craft to demonstrate hovering, detec- istics of the concept. however, (described tion and surveillance, air-sea rescue and under technology development), and a study other missions,. This program will be con- was sponsored to explore the potential ducted by the Navy. market for the type which included sev- eral concepts and configurations (Ref. 3). A few private efforts involving airship This study indicated that a substantial development also exist in addition to number of applications do exist. for heavy government sponsored programs,. One of vertical lift vehicles of various sizes. these, by D.C. Associatio n in Delaware, is These results are summarized in Table 1. described under Canadian programs. It can be seen that a leading application is in aerial logging. CAA a dEk - Several events in Canada have resulted from recent growth and development The Piasecki Corp. has also continued of the Northwest territories and some of to study various combinations of heli- the Western provinces. Studies sponsored copters and aerostats and has participated by the Ministry of Transportation identi- in several NASA and Navy sponsored studies fied several types of modern airships which to evaluate various aspects of the concept. might be suitable for transport systems in In 1980, the U.S. For,_:;t Service awarded this area (Ref. 5). Economic analyses in a contract, to be administered by the Navy, this study indicated that enormous savings to Piasecki for the development and opera- in transport expense were possible through tion of a Heli-stat for a demonstration the use of some kind of heavy-lift VTOL of aerial logging of Federal forests in the aircraft. These savings would accrue from U.S. Northwest. This vehicle is shown in the elimination of road construction - and Fig. 3. It will utilize a large number of reconstruction due to weather effects, component.; from Navy spare aircraft. The elimination of time dela;. by by-passing major components are four H•-34 helicopters obstructions (rivers, cantons) direct anti a 27611 m 3 Zm_ , Navy ci1r. hip delivery of men and equipMLnt, and exten- r?nve?lope. The helicopters will be modified sion of the working season. to ac:.comodate forward and reverse thrust propellers. This hybrid will lift a nominal The lagging of timber in these North- 25 tons of payload. It is be,nq constructed western regions is also an attractive use at the Naval Air Engineering Center at of heavy-lift hybrid airships.