gnesium and of a
dynamically balanced crankshaft) survive in modern reciprocating engine
designs. In addition, when it was first introduced, no other engine
could match it for economical fuel consumption and fuel safety. It also
had other less important advantages, but its disadvantages outweighed
all these advantages, as will be seen.

Description

Specifications

The following specifications are for the production engine and its
prototypes, known as the model DR-980:[11]

Type 4-stroke cycle diesel
Cylinders 9--static radial configuration
Cooling Air
Fuel injection Directly into cylinders at a pressure of
6000 psi
Valves Poppet type, one per cylinder
Ignition Compression--glow plugs for starting--air
compression 500 psi at 1000 deg. F.
Fuel Distillate or "furnace oil"
Horsepower 225 at 1950 rpm
Bore and stroke 4-13/16 in. x 6 in.
Compression ratio 16:1--maximum combustion pressure 1500 psi
Displacement 982 cu in.
Weight 510 lb without propeller hub
Weight-horsepower ratio 2.26 lb hp
Where manufactured U.S.A.
Fuel consumption .46 lb per hp/hr at full power
Fuel consumption .40 lb per hp/hr at cruising
Oil consumption .04 lb per hp/hr
Outside diameter 45-11/16 in.
Overall length 36-3/4 in.
Optional accessories Starter--Eclipse electric inertia; 6 volts.
Special series no. 7
Generator--Eclipse type G-1; 6 volts

[Illustration: Figure 17.--Longitudinal cross section, Packard diesel
engine DR-980. (Smithsonian photo A48845.)]

[Illustration: Figure 18.--Transverse cross section, Packard diesel
engine DR-980. (Smithsonian photo A48847.)]

[Illustration: Figure 19.--Right side view of engine, showing
accessories; Packard Motor Car Co. 50-hour test, 1930. A, starter; B,
oil filter. (Smithsonian photo A48323.)]

[Illustration: Figure 20.--Rear left view of engine, showing
accessories, U.S. Navy 50-hour test, 1931. Barrel valve type venturi
throttles. A, starter; B, oil filter; C, fuel circulating pump; D,
generator. (Smithsonian photo A48324C.)]

Operating Cycles

The sequences of operation of a