It could be argued
that the design brief for the Constellation was - "Compromise
on the side of loveliness". Regardless of the design
philosophy, it soon emerged that the aeroplane was often
capable of lifting more cargo than could be physically accommodated
within the holds of its elegantly curved fuselage. The solution
to this wasted performance potential was the so-called Speedpak.
The Speedpak was an external freight pannier contoured
to fit under the belly of the Constellation.
The Speedpak was never required on the Super Constellation
because its lengthened fuselage provided increased hold
capacity while the increased structural weight limited any
potential additional payload anyway.
of an empty Speedpak clearly shows the seven netted compartments
and the attaching hooks.
following description of the Speedpak is extracted from
Peter J. Marson's The Lockheed Constellation Series published
in 1982 by Air-Britain Historians and acknowledged with thanks.
Speedpak, developed by Lockheed Engineers at the behest
of Eastern Air Lines, was first tested on a Model 049 Constellation
(42-94558, c/n 1979). The Speedpak, carried under the
fuselage and closely fitting the fuselage contours, is 33
feet 4 inches long, 7 feet wide and 3 feet deep, with an overall
height when standing on the ground of 4 feet 6 inches and
weighing 1,836 pounds. The payload of the Speedpak
is 395 cubic feet and up to 8,200 pounds of freight can be
carried inside its seven compartments. A built-in electric
hoist lowers the Speedpak to the ground for loading
or unloading. For ease of movement on the ground, two semi-recessed
wheels are mounted underneath at each end of the container.
In spite of its size and weight, the Speedpak reduces
speed only by about 10 mph and range by about 4%. The Speedpak
was designed to enable a full load of passengers and a large
amount of cargo to be carried over the shorter stage-lengths
(or up to 2,200 miles with the later 749A) and enabled the
useful load of the Constellation to be increased considerably
with the new BD-1 engines. Eastern Air Lines and KLM both
ordered Speedpaks (14 and 7 respectively) in late 1946,
and several other airlines followed suit later. The four Speedpak
attachment points (stressed to 2.5g) were incorporated in
Constellations on the production line from c/n 049-2076 onwards,
and on all 649 and subsequent standard Constellations. A total
of 75 Speedpaks was built.
Speedpak aloft on VH-EAB Lawrence Hargrave during
pre-delivery test flying.
The four ground handling wheels are well illustrated in this view.
Speedpak on VH-EAA Ross Smith lowered for loading/unloading.
feet 4 inches
feet 0 inches
feet 0 inches
(from ground to top of container)
feet 6 inches
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