Design considerations for logistics are dealt with as they pertain to the large rigid LTA vehicle as either a commercial or military cargo carrier. Pertinent factors discussed are: (1) the basic mission; (2) types of payload; (3) the payload space in regards to configuration and sizing, its capacity, and its loadability. A logistic capability comparison of selected cargo airships versus jumbo jets is also made

Hackney, L. R. M.

English

NASA Technical Reports Server

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N76"!.5059
AIRSHIP LOGISTICS--
THE LTA VEHICLE A TOTAL CARC SYSTEM
L. R. "Mike" Hackney, P. E. * _.
ABSTRACT: This paper deals with the design consider- _
ations for logistics, as they pertain to the large rigid J ,_
LTA vehicle as either a commercial or military cargo
carrier. Pertinent factors discussed are: (I) the basic
-_'" mis3ion; (2) types of payload; (3) the payload space in
; regards to configuration and sizing, its capacity, and _
_ its loadability. A logistic capability comparison of
" _i selected cargo airships versus jumbo jets is also made.
,L
_ INTRODUCTION
i! AS a member of the "fixed-wing" aircraft fraternity for many years,_f
_ like all too many of us in aviation--the airship has been considered :
_ obsolete--a vehicle of the past. In brief, "elderly,windbags" to
_ quote from the title of a technical magazine article which summarized
!_ _he results of the AIAA meeting on LTA in Washington last winter, as
"a heavy dose of cold water."
The mere thought that the airship might be modernized to perform
i; certain of today's commercial and military logistic mlss_ons more
efficiently than a modern jet, helicopter, or VTOL vehicle, seemed
, inconceivable. However, after being exposed to the in-depth work and ;
_, logic of the LTA Technical Task Force of the Southern California
-: Aviation Council, Inc. (SCACI) and then joining same--sufficient valid
_ *President, Hackney Associates, Sierra Madre, California, U.S.A. and
_ Member LTA Technical Task Force of _ou_hern California Aviation
Council, fnc., Pasadena, California, U.S.A.
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evidence has been seen, to become con_inced that a "fresh and unbiased
look" at airship transportation is warranted.
: The purpose, therefore, during this workshop session is to discuss the
_ LTA vehicle as a total cargo system. Using as the basis the family of
seven rigid airship preliminary designs (ranging in size from 7.4
million cubic foot volume up to 55 million) developed by the LTA
4 Technical Task Force of SCACI. 2 To describe for consideration, an
airlift system which is unrestricted as to the size or weight of ship-
ments or geographic destination.
While today's wide-body jet aircraft represents the sixth or seventh
generation of progressive product improvement cycles, since the 1920- ,_
I 1930 time period--the same is far from the case for the lighter than
air vehicle. These often maligned craft, for all ostensible purposes,
are still in the state-of-the-art time-frames of the Fokker and Ford
tri-motor transports. _ Granted there has been some LTA development
_'" in the ensuing period by Goodyear. Unfortunately, however, la,=k of
funds and Government support for such vehicles precluded much in the
way of modernization as compared to fixed wing aircraft.
DESIGN CONSIDERATIONS FOR LOGISTICS
Obviously in the time allocated, it is not possible to adequately
cover the entire spectrum of LTA logistics. It was elected, there-
fore, to concentrate on the airship, as an airfrei@ht carrier. A
role for which it is uniquely suited--for airlifting both civil and
military cargoes. This is not to say that there are not a number of
other missions for which the LTA vehicle, when appropriately modified,
is not equally well qualified to perform. Fortunately, these are
being covered by others on this workshop agenda who are more inti-
mately qualified to discuss same.
' In the development of any future viable LTA configuration it is
imperative that "design considerations for logistics" be taken into
account concurrently along with all other major design factors. This
allows for timely analysis to determine the most effective tradeoffs--
before the fact rather than as a compromise after.
Basic Mission
As previously mentioned, for purposes of this discussion, the "basic
mission" is examined only as: (i) a long range commercial cargo
carrier, for either transcontinental operation; and/or (2) a very long
range heavy lift logistic carrier for the Military Airlift Command
(MAC), capable of operating non-stop from any U. S. aerial port of
embarkation to any location ove£seas. For either type mission the
basic configuration of the airship could well be much the same.
Types of Payload
As to types of payload, the large rigid LTA vehicle provides a true
intermodal cargo system capability. It offers an airlift system which
for all ostensible purposes is unrestricted as to a shipment's weight
or size. As to the upper end of the spectrum, it is forseeable that
single shipments of over 300 tons or more will be moving by air.
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1976007927-525
This is evidenced by the presence of Combustion Engineering, Inc.,
transportation experts on the LTA Workshop program. C-E's Industrial
Boiler Operations Division with its Schnabel car (maximum capacity
600,000 ibs.) developed for boiler transport has been moving its
220,000 lb. Type A units over the U.S. rail network for several years 4. <
Manufacturers of large steam turbines and condensers, electric genera-
tors, forging presses, nuclear powerplant components, etc., have
_ similar heavy lift transportation requirements.
A viable LTA vehicle offers the opportunity for greatly expanding the
dimensional envelope restrictions now imposed by rail movement. No
longer would it be necessary for builders of massive industrial equip- _
ment, as their respective product line grows in weight and size--to
consider relocatiun of their expensive facilities adjacent to inland •
waterways or seacoasts. They can continue to factory assemble and
pretest their huge units--thus avoiding the expensive process of ¢
assembly in the field. Further they ca. put their units into service
"_'" more quickly after delivery to the site.
In addition to the massive or so-called extra heavy and outsize pay-
loads just discussed, the large rigid airship should likewise be
ideally suited for carrying all types and sizes of commercial and
military vehicles. These can range up to the biggest truck mounted
industrial crane, or to the Army's largest mobile combat equipment.
Regarding the more conventional types of commercial payloads present-
ly moving by air on wide body cargo jets--the airship can readily
accomodate these, including all types of ISO containers up _o 40'.
However, as to a very few types of commodities which might be carried
therein (or separately)--there is question of the need for pressur-
ization. For instance, certain pharmaceutical shipments may require a
._ pressurized cargo compartment or its own pressurized container. Such
!_ specializeJ cargo traffic, however, is well below one percent of the
total moving by air today.
As to air traffic of fresh fruits and vegetables as well as fresh
flowers and nursery stock, both groups of which move in sizeable
volume--it was at one time believed these were sensitive to altitude.
Regarding fruits and vegetables, controlled laboratory tests have
shown no adverse effects of altitude up to 30,000 feet and rates of
climb or descent up to 3,000 feet per minute 5, while altitudes as high
as 20,000 feet had no effect on the flowers tested.
The Payload Space
During the recent resurgence of interest i:, LTA transportation systems,
considerable material has been written and attention given to the air-
ship a_ a whole--its hull design, powerplants, performance, economics,
etc. Unfortunately however, little work or attention appears to have
been given to the airship's payload space (or in the case of the °_
military--useful load) requirements, and the design considerations
relating thereto. It is trusted that the contents of other workshop
papers will indicate this is no longer the case. In the event this
is not so, it cannot be emphasized too strongly that this Js an area
which warrants much in-depth study by the LTA payloads design engineer.
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1976007927-526
I Configuration and Sizlng--First, a decision must be made as to the
types and sizes cf commercial and/or military cargoes, the payload
_] compartment (or compartments) will be designed to accomodate. To
mention a few, such questions which must be answered:
lj I. Will outsize and heavy shipments be airlifted, s_ch as
boilers, turbines, generators, etc? If so, will they be /
_ carried within the airship hull or suspended beneath? If
carried internally, what are the cargo deck area require-
ments for spreading such concentrated bearing loads7 q
l
i 2. Assuming that ISO type intermode containers are carried,
what will the cell arrangement be for storing same-- _
single, double, or tiers? Will the containers be alignedfore and aft or thwartship in the payloa@ compartment?
3. What are the number, size, and location of all cargo _
compart_.ent access hatches (doors)? Will these be side _
entrance or bottom entrance hatches, or both?
Capacity--It is the practice of the U. S. Maritime Commission to use
the 20' ISO container, as the common denominator, when rating the
capacity of containerships 7. As the LTA vehicle is for all purposes
a ship, rather than an aircraft--it seems logical to follow suit--at
least as one means of measuring cargo capacity.
Take for example the large rigid airship preliminary design MC-55
(55 million cu. ft. volume)--the largest of the seven classes de-
, veloped as part of SCACI's Technical Task Force Report 8. This LTA
vehicle was estimated to have a cargo payload of some 1,026 tons at
6,000 statute miles. Based on past experience however, it has been
observed that sufficient weight is seldom allocated for today's
i sophisticated onboard cargo handling and restraint systems and the
supporting structure required for same. Therefore, an additional 26
tons (52,000 ibs.) is arbitrarily transferred, thus reducing the pay-
load to 1,000 tons.
The common 20' ISO dry container's useful volume averages 1,100 cu.
ft. per van. Thus:
20' Van Payload Cap. @ 15 ibs./cu/ft
& 85% cube utilization = 14,025 ibs.
20' Van Tare Weight @ 3,375 Ibs.
Total 17,400 ibs. or 8.7 tons
1,000 tons
_.7 tons = 115 20' Container Capacity for the MC-55
As to the cargo space requirements to accomodate 115 20' containers.
Allowing (8.5' x 20.5') ].75.25 sq. ft. per unit, plus allocating some
(174.25 sq. ft. x 5) 871.25 sq. ft. for cargo entrance hatches. The
115 units if stowed as a single tier--would require a cargo compart-
ment of 51' in width by 410' in length. This is predicated on the
containers being aligned fore and aft six abreast, with _our rows
of 20 each, one of 18 and one of 17 units.
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Loadability--Obviously there are a number of container storage
patterns which are feasible--two or three tiers high, etc. 9 All of
these justify a so-called "loadability study" using a systems engi-
neering approach, before final selection. For loadability per s_,
involves the entire cargo loading and handling operations cycle--
both into or out of the airship as well as the interfacing c_rgo
procedures on the ground. One example of loadability would be--should
i a roll-on, roll-off capability be provided for the large LTA vehicle? /
Ro/Ro ships are growing in popularity in the maritime trade, as it
permits all types of wheel vehicles to be readily driven on and off
the vessel under their own power.
The On-Board Cargo Handling System
This is an area which is wide open to new ideas and innovations. It
would be a most se_ious mistak for LTA payload designers to attempt ::
to adopt or modify cargo jet aircraft loading systems for the airship
without first taking into consideration all factors.
While these systems are satisfactory for aircraft--commerce of the
type which the airship will be transporting, make it a somewhat
different ball game. To name a few:
i. The aircraft car_o handling is aircraft movement oriented--
not surface movement oriented. It is the outgrowth as well
: as the victim of the old 463 L Universal Cargo Pallet
System which was initiated in the days of the Douglas C-124
transport. It started with the introduction of the 88"x 105"
military cargo pallet--so sized that it could pass through
this aircraft's bottom loading cargo hatch.
2. This system from its inception has espoused handling all
aircraft type palle_s, unit load devices, and containers--
up to and inclL1ding ISO size, from the bottom, on various
types of roller conveyor systems. In consequence, most all
intermodal ISO containers offered for air mevement must
first be placed on a special slave pallet before entering
any wide body cargo jet.
3. On the other hand surface cargo, and ISO size containers in
particular, are designed for hoisting from above, using
the standardized corner fittings incorporated therein.
As world commerce, with few exceptions, moves in these sea-
l_nd type containers rather than SAE AS 832 air-land
demountable containers--any LTA logistics should take this
fact into account.
4. The LTA cargo hoisting system will undoubtedly be patterned
to a degree after the large quay side gantry crane systems
used by containership terminals.
_ LOGISTIC CAPABILITY COMPARISON
I_ trade press coverage is any indication--it appears that 1974 will
be known as "the year of the jumbo jet freighter." For this year is
seeing a number of U.S. and foreign carriers following L_fthansa's
footsteps, by introducing their own 747 F equipment--and thus offer
_i van _ize container service.
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1976007927-528
Cargo Compartment Access
Recognition of shipper demand to extend the outsize cargo capability
of the 747 F, is _videnced by the 10'xll' side carqo door being in-
stalled aft of the wing by a Dumber of operators. II This feature
o%ercomes the 8' height limit on containers loaded through the
standard nose door. In fact, Boeing is considering elevating the 747
_ flight deck 38"--thus increasing the nose door from 8'2" to 11'4" in
height and from 11'8" to 12'9" in width at the floor. 12 One objective
being to increase the aircraft's ability to load and carry outsize
military equipment.
The purpose of discussing the continuing efforts of the airframe i
constructor to provide improved access to the cargo compartment of _,
its aircraft--is to draw a comparison with the ease of doing such work
to a metal airship hull. Further, it is possible to incorporate much
larger access provisions, as well as a greater number, for far less
_,_.-_ cost and weight. This is due to the relative simplicity of the LTA '
hull structure and its ability to accommodate sizeable cut-outs, with
only minor beef-up to the surrounding structure.
Van Container Capacity
It was interesting to note that one jumbo jet operator has recently
elected to describe its new 15 slot 20' container capacity cargo
aircraft as "containerships. "13 Yet this is a mere David in compari-
son with Sea-Lanu _ new Goliath SL-7 supercontainerships. These
946', 51,000 ton vessels have a slot capacity for the equivalent of
over 2,000 20' units.
To give a picture of 20' container capacities for the existing or
proposed fanily of U.S. jumbo cargo jets--versus lighter than air
containerships, the following figures are presented based on the
listed assumptio_.
Assumptions:
i. For 3umbo jet freighters: 20' van capacity 0 !,i00 cu. ft x
15 ibs. cu. ft. cargo density x 85(%) percent cube utilization =
14,025 ibs. plus van tare weight (for SAE AS 832 Air-Land
demountable cargo container) of 2,200 ibs. A total weight of
16,225 Ibs. or 8.1 tons per container.
2. For LTA freighters: tare weight of 20' container increased from
2,200 ibs. to 3,375 ibs. to allow for heavier surface type units.
Thus, 14,025 Iks. + 3,375 Ibs. = 17,400 ibs. or 8.7 tons per
container.
3. Payload of all MC-series LTA freighters arbitrarily reduced
2.5 (%_ percent to allow for onboard cargo loading and handling
systems.
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20' Intermode Container Capacity
Jumbo Jet Freighters 14 LTA Freighters
Manufacturer Container SCACI Series Container
and Model CaPacity (Model No.) Capacity_
Douglas C-2 6 MC-7.4 i0
Douglas DC-10 6 MC-15 26
Lockheed I011 6 MC-22 41 _i
Douglas C-4 12 MC-35 67 ,
Lockheed L-500 (C-5A) 14 MC-42 84 _
Boeing 747F 15 MC-52 98 _,
Douglas C-6 28 MC-55 115
t
REFERENCES :
I. Technology Review magazine, Diriqibles: Think of Elderl[ Wind-
bags, (July/August, 1974).
2. Southern California Aviation Council, Inc. (SCACI), Committee
on Lighter Than Air, Technical Task Force Report, (May 15, !974).
3. The LTA Committee, SCACI, Lighter Than Air Transportation
Feasibility Study - Proposal, (March, 1974) p._.
4. Handling and Shipping magazine, The Midas Touch of a Ph[sical
__ Distribution Idea, (August, 1974) p.p. 5_57.
" _ 5. Hackney, L. R. and Rose, B. A., Altitude Tests on Fruits and
!_ Vegetables, Lockheed Air Cargo Progress Report, (February 15, 1949).6. Della-Vedowa, R. P. and Rose, B. A., Altitude Tests on Flowers,
,_ Lockheed Air Cargo Progress Report, (September,)950).
!_ 7. Hackney, L. R., The Emergin_ Influence of the Intermodal
iv Container, The Institute of Airline Marketing, (March 6-7, 1969) p.6.
8. Reference 2, p.63
9. Ilackney, L. R., An Overnead Rail Automated Staging System for
Containershi_ Terminals, Stanray Corporation, (October, 1968), p.55.
10. Ilackney, L. R., International Air Cargo--Its Future Ground
Environment, International Air Cargo Forum--Air Age '70, (July, 19_0),
_ ii. Commercial News (weekly), U. S. Trunk line to inaugurate 747
_J Freighter Service, (September 2, 1974) p.l.
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1976007927-530
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12. Aviation Week, 747 _]ose-Loadin% Door Growth Studied,
(September 2, 1974) p_25.
i 13. Commercial News, !_ll-Car_o Airline Takes Delivery of Boeing 747F
Freighter, (August 12, 1974) p.ll
14. Reference 10, figure 2.
15. Reference 2. pp. 57 through 63.
! .
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Airship logistics: The LTA vehicle; a total cargo system

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