TL 
515 
.S66 
v.l 
no.2 
MSRL 
MITHSONIAN 
ANNALS 
FLIGHT 
The First Airplane Diesel Engine: Packard 
Model DR-980 of 1928  ? Robert B. Meyer 
VOLUME 1 
NUMBER 2 
SMITHSONIAN    INSTITUTION 
NATIONAL AIR MUSEUM      ?      Washington, D.C 
Frontispiece?President Herbert Hoover (in front of microphones) presenting the 
Collier Trophy to Alvan Macauley (nearest engine), President of the Packard Motor 
Car Co., on March 31, 1932 (although the award was for 1931). Also present were 
Hiram Bingham, U.S. Senator from Connecticut (nearest pillar), Clarence M. Young, 
Director of Aeronautics, U.S. Department of Commerce (between Macauley and 
Hoover), and Amelia Earhart, first woman to fly across the Atlantic Ocean (between 
Macauley and the engine). In the foreground is a cutaway Packard diesel aero- 
nautical engine, and directly in front of Senator Bingham is the Collier Trophy, 
America's   highest   aviation   award.    (Smithsonian photo A48825.) 
SMITHSONIAN ANNALS OF FLIGHT 
VOLUME 1      ?      NUMBER 2 
The First Airplane Diesel Engine: 
Packard Model DR-980 of 1928 
ROBERT B. MEYER 
Curator of Flight Propulsion 
SMITHSONIAN INSTITUTION   ?   NATIONAL AIR MUSEUM 
WASHINGTON, D.C.    ?    1964 
The following microfilm prints are available at the Smithsonian 
Institution : 
"The Packard Diesel Aircraft Engine?A New Chapter in Trans- 
portation Progress." An advertising brochure produced by the 
Packard Motor Car Company in 1930, illustrated, 17 pages. 
Fifty-Hour Test of the Engine by the Packard Company, 1930. 
Text and charts, 14 pages. 
Fifty-Hour Test of the Engine by the U.S. Navy in 1931: Text 
and charts, 26 pages. 
Packard Instructional Manual, 1931.   Illustrated, 74 pages. 
"The Packard Diesel Engine," Aviation Institute of U.S.A. 
Pamphlet No. 21-A, 1930.   Illustrated, 32 pages. 
For sale by the Superintendent of Documents, U.S. Government Printing Office 
Washington, D.C., 20402     Price 60 cents 
IV 
Contents 
Page 
ACKNOWLEDGMENTS  vi 
FOREWORD  vii 
INTRODUCTION  1 
History  2 
DESCRIPTION  11 
Specifications  11 
Operating Cycles  13 
Weight-Saving Features  15 
Diesel Cycle Features  20' 
Development  23 
COMMENTS  27 
ANALYSIS  33 
Advantages  33 
Disadvantages  35 
APPENDIX 
1. Agreement Between Hermann I. A. Dorner and Packard 
Motor Car Company  43 
2. Packard to Begin Building Diesel Plane Engines Soon. . 46 
3. Effect of Oxygen Boosting on Power and Weight  47 
Acknowledgments 
It is difficult to acknowledge fully the assistance given by persons and 
museums for the preparation of this book. However, I wish especially to 
thank Hugo T. Byttebier, engine historian, Buenos Aires, Argentina; Dipl. 
Ing. Hermann I. A. Dorner, diesel designer, Hanover, Germany; Harold E. 
Morehouse, and C. H. Wiegman, Lycoming Engines, Williamsport, Penn- 
sylvania; Barry Tully, Goodyear Aircraft, Akron, Ohio; Richard S. Allen, 
aviation author, Round Lake, New York; William H. Cramer, brother of 
Parker D. Cramer, Wantagh, New York; Erik Hildes-Heim, Early Bird 
and aviation historian, Fairfield, Connecticut. 
I am particularly grateful to curators of the following museums who have 
been so generous in their assistance: Deutsches Museum, Munich, Germany 
(Dipl. Ing. W. Jackie) ; Henry Ford Museum, Dearborn, Michigan (Leslie, 
R. Henry); U.S. Air Force Museum, Wright-Patterson Air Force Base, 
Dayton, Ohio (Maj. Robert L. Bryant, Jr., director); Science Museum, 
London, England (Lt. Comdr. (E) W- J. Tuck, Royal Navy). The 
preparation of this paper could not have been accomplished without the 
aid of the National Air Museum of the Smithsonian Institution and the 
help of Philip S. Hopkins, director, and Paul E. Garber, head curator and 
historian. 
VI 
Foreword 
In this second number of the Smithsonian Annals of Flight, Robert B. 
Meyer Jr., curator and head of the flight propulsion division, tells the 
story of the first oil-burning engine to power an airplane, the Packard 
diesel engine of 1928, now in the collections of the National Air Museum. 
The author's narrative, well illustrated with drawings and photographs, 
provides a historical background for the development of the engine, and a 
technical description that includes specifications and details of performance. 
It also contains comments from men and women who flew planes powered 
by the Packard diesel. The author concludes with an analysis of the 
engine's advantages and disadvantages. 
PHILIP S. HOPKINS 
Director. National Air Museum 
30 July 1964 
vi i 
Introduction 
On display in the National Air Museum, Smithsonian Institution, is the 
first oil-burning engine to power an airplane. Its label reads: "Packard 
Diesel Engine?1928?This first compression-ignition engine to power an 
airplane developed 225 hp at 1950 revolutions per minute. It was designed 
under the direction of L. M. Woolson. In 1931, a production example of 
this engine powered a Bellanca airplane to an 84 hour and 33 minute non- 
refueled duration record which has never been equalled. ?Weight/power 
ratio: 2.26 lb per hp?Gift of Packard Motor Car Co." 
Figure 1 (left).? Front view of first Packard diesel, 1928. Note hoop holding cyl- 
inders in place and absence of venturi throttles. This engine was equipped with an 
air pressure starting system. (Smithsonian photo A2388.) Figure 2 (right).? Left 
side view of first Packard diesel, 1928. Heywood starter (air) fitting shown on 
the head of the next to lowest cylinder.    (Smithsonian photo A2388C.) 
1 
This revolutionary engine was created in the short time of one year. 
Within two years of its introduction in 1928, airplane diesel engines were 
being tested in England by Rolls-Royce, in France by Panhard, in Germany 
by Junkers, in Italy by Fiat, and in the United States by Guiberson. 
Packard had demonstrated to the world the remarkable economy and safety 
of the airplane diesel engine, and the response was immediate and favorable. 
The novelty and performance of the Packard diesel assured it a large and 
attentive audience wherever it was exhibited. Yet in spite of its perform- 
ance record the engine was doomed to failure by reason of its design, and 
it was further handicapped by having been rushed into production before 
it could be thoroughly tested. 
History 
The official beginning of the Packard diesel engine can be traced to a 
license agreement dated August 18, 1927, between Alvan Macauley, presi- 
dent of the Packard Motor Car Company of Detroit, Michigan, and Dipl. 
Ing. Hermann I. A. Dorner, a diesel engine inventor of Hanover, Germany.1 
Before the agreement was drawn up, Capt. Lionel M. Woolson, chief aero- 
nautical engineer for Packard, tested an air-cooled and a water-cooled 
diesel that Dorner had designed and built in Germany.2 Both engines 
attained the then high revolutions per minute of 2000 and proved efficient 
and durable. They demonstrated the practicability of Dorner's patented 
"solid" type of fuel injection which formed the basis of the Packard diesel's 
design.3 Using elements from Dorner's engines, Woolson and Dorner 
designed the Packard diesel with the help of Packard engineers and Dor- 
ner's assistant, Adolph Widmann. Woolson was responsible for the weight- 
saving features, and Dorner for the combustion system. 
The historic first flight took place on September 19, 1928, at the Packard 
proving grounds in Utica, Michigan, just a year and a month from the 
day Dorner agreed to join the Packard team. Woolson and Walter E. 
Lees, Packard's chief test pilot, used a Stinson SM-1DX "Detroiter." The 
flight was so successful, and later tests were so encouraging, that Packard 
1
 Appendix, p. 43. 
2
 Letter, Hermann I. A. Dorner to National Air Museum, March 3, 1962. 
3
 See p. 20 if. 
Figure 3.?Alvan Macauley (left), President of the Packard Motor Car Co. and 
Col. Charles A. Lindbergh with the original Packard diesel-powered Stinson 
"Detroiter" in the background, 1929.    (Smithsonian photo A48319D.) 
built a $650,000 plant during the first half of 1929 solely for the production 
of its diesel engine. The factory was designed to employ more than 600 
men, and 500 engines a month were to have been manufactured by July 
1929.4 
The engine's first cross-country flight was accomplished on May 13, 
1929, when Lees flew the Stinson SM-1DX "Detroiter" from Detroit, 
Michigan, to Norfolk, Virginia, carrying Woolson to the annual field day of 
the National Advisory Committee for Aeronautics at Langley Field.   The 
4
 Appendix, p. 46. 
Figure 4.?Dipl. Ing. Hermann I. A. 
Dorner, 1930, German diesel engine 
designer, was responsible for the 
diesel cycle used in the Packard 
DR-980 aircraft engine. (Smithsonian 
photo A48645.) 
Figure 5.?Capt. Lionel M. Woolson, 
1931, Chief Aeronautical Engineer, 
Packard Motor Car Co. Designer of 
Packard DR-980 diesel engine. 
(Smithsonian photo A48645A.) 
700-mile trip was flown in 6% hours, and the cost of the fuel consumed was 
$4.68. Had the airplane been powered with a comparable gasoline engine, 
the fuel cost would have been about 5 times as great.5 On March 9, 1930, 
using the same airplane and engine, Lees and Woolson flew from Detroit, 
Michigan, to Miami, Florida, a distance of 1100 miles in 10 hours and 15 
minutes with a fuel cost of $8.50. The production engine, slightly refined 
from the original, received the first approved type certificate issued for any 
diesel aircraft engine on March 6, 1930. The Department of Commerce 
granted certificate no. 43 after the Packard Company had ground- and 
flight-tested this type of engine for approximately 338,000 hp hr, or about 
1500 hr of operation.6 
One of the early production versions powered a Bellanca "Pacemaker" 
which was piloted by Lees and his assistant Frederic A. Brossy to a world's 
5
 Aeronautics (October 1929), vol. 5, no. 4, p. 32. 
6
 The Packard Diesel Aircraft Engine?A New Chapter in Transportation Progress (Detroit: 
Packard Motor Car Co., 1930), p. 5. 
nonrefueling heavier-than-air duration record. The flight lasted for 84 
hours, 33 minutes from May 25 through 28, 1931, over Jacksonville, Florida. 
This event was so important that it was the basis of the following editorial, 
published in the July 1931 issue of Aviation,1 which summarizes so well the 
progress made by the diesel engine over a 3-year period and the hope held 
for its future: 
A RECORD CROSSES THE ATLANTIC?The Diesel engine took its 
first step toward acceptance as a powerplant for heavier-than-air craft when, 
in the summer of 1928, a diesel-powered machine first flew. The second step 
was made at the 1930 Detroit show, when the engine went on commercial sale. 
The third was accomplished last month, when a plane with a compression- 
ignition engine using furnace oil as a fuel circled over the beaches around 
Jacksonville for 84 hours and inscribed its performance upon the books as a 
world's record?the longest flight ever made without intermediate refueling. 
With the passing of the refueling-duration excitement, and with the 
apparent decision to allow that record to stand permanently at its present level, 
trials for straight time in the air without replenishment of supplies begin to 
regain a proper degree of appreciation. No other record, unless it be some of 
those for speed with substantial dead loads, is of such importance as the non- 
stop distance and duration marks. No other has such bearing upon precisely 
those qualities of aerodynamic efficiency, fuel economy, and reliability of air- 
plane and powerplant that most affect commercial usefulness. It is more than 
three years since the duration record left American shores, and it has been 
more than doubled in that time.   Its return is very welcome. 
It is doubly welcome for being made with a fundamentally new type of 
engine. The diesel principle is not a commercial monopoly. It is open to 
anyone. Already two different designs in America, and one or two in Europe, 
have been in the air. For certain purposes, at least, it seems reasonable to 
expect that its special advantages will bring it into widespread use. Every 
practical demonstration of the progress of the diesel toward realizing its theo- 
retical possibilities in the air as it has realized them on the land and at sea is a 
bit of progress toward better and more economical commercial flying, and so 
benefits the whole industry. The fourth, and next, main element in the demon- 
stration will be provided when diesels go into regular service on some well- 
known transport line as standard equipment, and the accumulation of data 
on performance under normal service conditions begins. We believe that 
that will happen before the end of 1932. 
Many men, from Dr. Rudolf Diesel to Walter Lees and Frederic Brossy, 
have had direct or indirect hands in the making of this record. The greatest 
of all contributions was that of Lionel M. Woolson, who created the engine 
7
 A memorial to Woolson who was killed in the crash of a Packard diesel-powered 
Verville "Air Sedan" on April 23, 1930. 
Figure 6? Stinson SM-1 DX "Detroiter." 
This airplane, powered with original 
Packard DR-980 diesel engine, made 
the world's first diesel-powered flight 
on September 19, 1928. (Photo courtesy 
of Henry Ford Museum, Dearborn, 
Michigan.) 
Figure 7. ? Packard-Bellanca "Pace- 
maker." This airplane, powered by a 
Packard DR-980 diesel, holds the 
world's record for nonrefueling, heavier- 
than-air aircraft duration flight. The 
flight lasted 84 hours, 33 minutes, ]]A 
seconds, and was completed on May 28, 
1931, Jacksonville, Florida. (Smith- 
sonian photo A48446B.) 
Figure 8.?Verville "Air Coach," Octo- 
ber 1930.    (Smithsonian photo A48844.) 
Figure 9.?Packard-Bellanca "Pace- 
maker" owned by Transamerican Air- 
lines Corporation and used by Parker D. 
Cramer, pilot, and Oliver L. Paquette, 
radio operator, in their flight from De- 
troit, Michigan, to Lerwick, Shetland 
Islands, summer 1931. (Smithsonian 
photo A200.) 
Figure 10.?Ford 11-AT-1 Trimotor, 1930, 
with 3 Packard 225-hp DR-980 diesel 
engines. Note special bracing for the 
outboard nacelles. (Smithsonian photo 
A48311B.) 
Figure 11,?Towle TA-3 Flying Boat, 
1930, with 2 Packard 225-hp DR-980 
diesel engines. (Smithsonian photo 
A48319.) 
Figure 12.?Stewart M-2 Monoplane, 
1930, With 2 Packard 225-hp DR-980 
diesel engines. (Smithsonian photo 
A48319C.) 
Figure 13.?Consolidated XPT-8A, 1930. 
This is a Consolidated PT-3A powered by 
a DR-980 Packard diesel. (Smithsonian 
photo A48319E.) 
and flew with it in every test and brought it through its early troubles to the 
point of readiness for the commercial market. The flight that lasted four days 
and three nights is his memorial, quite as much as is the bronze plaque unveiled 
last April in the Detroit show hangar. 
The Robert J. Collier Trophy, America's highest aviation award, was 
won by the Packard Motor Car Company in 1931 for its development of 
the diesel engine. The formal presentation was made at the White House, 
March 31, 1932, by President Hoover on behalf of the National Aeronautic 
Association. Al van Macauley, president of the Packard Motor Car Com- 
pany, accepted the trophy, saying: "We do not claim, Mr. President, that 
we have reached the final development even though our diesel aircraft 
engine is an accomplished fact and we have the pioneer's joy of knowing 
that we have successfully accomplished what had not been done 
before . . . . "8 The amazing early success of the Packard diesel is 
illustrated by the following chronological summary : 
1927?License agreement signed between Alvan Macauley and Her- 
mann I. A. Dorner to permit designing of the engine. 
1928?First flight of a diesel-powered airplane accomplished. 
1929?First cross-country flights accomplished. 
1930?Packard diesels were sold on the commercial market and were 
used to power airplanes manufactured by a dozen different American 
companies. 
1931?World's official duration record for nonrefueled heavier-than- 
air flight.   First flight across the Atlantic by a diesel-powered airplane. 
1932?Packard diesels tested successfully in the Goodyear nonrigid 
airship Defender.9 Official American altitude record for diesel-pow- 
ered airplanes established (this record still stands). 
In spite of this promising record, the project died in 1933. The Decem- 
ber 1950 issue of Pegasus gave two reasons for the failure of the engine : "One 
blow had already been dealt the program through the accidental death of 
Capt. L. M. Woolson, Packard's chief engineer in charge of the Diesel 
development, on April 23, 1930. Then the Big Depression took its toll in 
research work everywhere and Packard was not excepted." 
The engine did not fail for the above mentioned reasons. Capt. 
Woolson's death was indeed unfortunate, but there were others connected 
with the project who carried on his work for three years after he passed away. 
8
 Packard Inner Circle (April 18, 1932), vol. 17, no. 6, p. 1. 
9
 Aero Digest (February 1932), vol. 20, no. 2, p. 54. 
8 
8etf??? ?? 
Cf. 
Figure 14.?Walter E. Lees, Packard chief test pilot (in cabin) and Frederic A. 
Brossy, Packard test pilot, before taking off on their world's record, nonrefueling, 
heavier-than-air aircraft duration flight, which lasted 84 hours, 33 minutes, and 
VA seconds.    (Smithsonian photo A48446E.) 
Figure 15.?Walter E. Lees, official timer, and Ray Collins, manager, 1930 National 
AirTour, with their official airplane, a Packard diesel Waco "Taper Wing," at Packard 
proving grounds near Detroit.    (Smithsonian photo A49449.) 
Figure 16.?Capt. Karl Fickes, 
acting head of Goodyear's air- 
ship operations, pointing out 
features on one of the 
"Defender's" Packard diesel 
engines to Roland J. Blair, 
Goodyear airship pilot, Akron, 
Ohio. From "Aero Digest," 
February 1932. (Smithsonian 
photo A49674.) 
The big depression was also unfortunate, but it did not stop aeronautical 
engine development. "It was a time when such an engine would have been 
most welcome if it had been produced in large enough numbers to bring the 
price down to compare favorably pricewise with gas engines of the same 
horsepower class."10 The Packard diesel failed because it was not a good 
engine. It was an ingenious engine, and two of the several features it 
pioneered (the use of magnesium 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 con- 
sumption and fuel safety. It also had other less important advantages, but 
its disadvantages outweighed all these advantages, as will be seen. 
Letter, Richard Totten to National Air Museum, January 28, 1964. 
10 
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 com- 
pression 500 psi at 1000? F. 
Fuel   Distillate or "furnace oil" 
Horsepower   225 at 1950 rpm 
Bore and stroke    4% 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   451#6 in. 
Overall length   36% in. 
Optional accessories... .   Starter?Eclipse electric inertia; 6 volts.   Spe- 
cial series no. 7 
Generator?Eclipse type G?1 ; 6 volts 
11
 Instruction Book for the Packard-Diesel Aircraft Engine (Detroit: Packard Motor Car 
Company, 1931), p. 3. 
11 
SHIM FRONT ?EARING TO  
PROVIDE .035 TO .045 
CLEARANCE BETWEEN SIDE 
OF ROLLER AND UP OF BEARING 
BOTH FRONT AND REAR 
THlUVHkUTM- 
rafmONEDtOAITO 
?O?? TO <JO EM) 
PLAY OF TU?E 
Figure 18.?Transverse cross section, Packard 
diesel engine DR-980. (Smithsonian photo 
A48847.) 
Figure 17.?Longitudinal cross section, Packard 
diesel engine DR-980. (Smithsonian photo 
A48845.)  ' 
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.) 
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 Packard diesel engine compared with 
those of a 4-stroke cycle gasoline engine are illustrated in figure 21. 
Brief Analysis of Action in a Four-Cycle Gasoline Engine 
Mixture of air and 
gasoline enters cyl- 
inder   from   carbu- 
retor. 
Atmospheric air 
only, enters cylinder 
through single valve. 
Mixture    is    com- 
pressed into smaller 
volume    by    piston 
moving upward. 
An electric spark 
ignites the com- 
pressed mixture 
causing it to explode. 
Combustion heat in- 
creases the cylinder 
pressure forcing pis- 
ton downward. 
Similar Action in the Packard-Diesel Aircraft Engine 
Air is so greatly 
compressed by up- 
ward moving piston 
that it reaches tem- 
perature of 1000? F'. 
\^y 
Just before piston is 
at dead center fuel 
oil is sprayed into 
cylinder and spon- 
taneously ignited. 
Power  of this   ex- 
plosion is parsed to 
crankshaft   in   con- 
ventional manner. 
Momentum carries 
piston upward which 
pushes burnt gases 
out through the ex- 
haust valve. 
Piston forces out 
burnt gases through 
same single valve 
which is cooled by 
inrush of new air as 
cycle repeats. 
Figure 21.?Operating cycles.    (Smithsonian photo A48846.) 
Although the size, weight, and general arrangement of the Packard 
diesel did not differ radically from conventional gasoline engines of a similar 
type, there were definite differences caused by the diesel cycle. In the 
words of Capt. Woolson : 12 
12
 S.A.E. Journal (April 1930), vol. 24, no. 4, pp. 431 and 432. 
13 
As this engine operates on an entirely different principle than the gasoline 
engines used heretofore in aircraft, it is desirable before launching into a 
mechanical description to consider first in a general way the principles of 
operation of the Diesel cycle as opposed to the Otto cycle principle on which 
nearly all gasoline engines operate. 
The real point of departure between the two systems of operation is the 
ignition system involved. In the gasoline engine an electric spark is depended 
upon to fire a combustible mixture of gasoline vapor and air which mixture 
ratio must be maintained within rather narrow limits to be fired by this 
method .... 
In the Diesel engine, air alone is introduced into the cylinders, instead of a 
mixture of air and fuel as in the gasoline engine, and this air is compressed into 
much smaller space than is possible when using a mixture of gasoline and air, 
which would spontaneously and prematurely detonate if compressed to this 
degree. The temperature of the air in the cylinder at the end of the compression 
stroke of a Diesel engine operating with a compression ratio of about 16:1 is 
approximately 1000 degrees Fahr., which is far above the spontaneous-ignition 
temperature of the fuel used. Accordingly, when the fuel is injected in a highly 
atomized condition at some time previous to the piston reaching the end of its 
stroke, the fuel burns as it comes in contact with the highly heated air, and the 
greatly increased pressures resulting from the tremendous increase in tempera- 
ture brought about by this combustion, acting on the pistons, drive the engine, 
as in the case of the gasoline engine. 
Summing up, the differences between the Diesel and gasoline engines start 
with the fact that the gasoline engine requires a complicated electrical ignition 
system in order to fire the combustible mixture, whereas the Diesel engine 
generates its own heat to start combustion by means of highly compressed air. 
This brings about the necessity for injecting the fuel in a well-atomized condi- 
tion at the time that combustion is desired and the quantities of fuel injected at 
this time control the amount of heat generated ; that is, an infinitesimally small 
quantity of fuel will be burned just as efficiently in the Diesel engine as a full 
charge of fuel, whereas in the gasoline engine the mixture ratio must be kept 
reasonably constant and, if the supply of fuel is to be cut down for throttling 
purposes, the supply of air must be correspondingly reduced. It is this 
requirement in a gasoline engine that necessitates an accurate and sensitive 
fuel-and-air metering device known as the carburetor. 
The fact that the air supply of a Diesel engine is compressed and its 
temperature raised to such a high degree permits the use of liquid fuels with a 
high ignition temperature. These fuels correspond more nearly to the crude 
petroleum oil as it issues from the wells and this fact accounts for the much 
lower cost of Diesel fuel as compared to the highly refined gasoline needed for 
aircraft engines. 
14 
Weight-Saving Features 
In order to be successful in aviation use, the modern lightweight diesel 
of the time had to have its weight reduced from 25 lb/hp to 2.5 lb/hp. 
This required unusual design and construction methods, as follows: 
Crankcase : It weighed only 34 lb because of three factors : Magnesium 
alloy was used extensively in its construction, thus saving weight as compared 
Figure 22.?Rear view of engine with rear crankcase cover removed, showing valve 
and injector rocker levers and injector control ring mounted on crankcase diaphram. 
U.S. Navy test, 1931.    (Smithsonian photo A48323D.) 
15 
Figure 23.?Main crankcase.   U.S. Navy test, 1931.    (Smithsonian photo A48325B.) 
with aluminum alloy, which was the conventional material at this time. 
It was a single casting. This saved weight because heavy flanges, nuts, and 
bolts were dispensed with. The cylinders, instead of being bolted to the 
crankcase, as was normal practice, were held in position by two circular 
hoops of alloy steel passing over the cylinder flanges. They were tightened 
to such an extent that at no time did the cylinders transfer any tension 
loads to the crankcase. This type of fastening actually strengthened the 
crackcase in contrast to the usual method. For this reason it could be 
built lighter.   The hoops did not always function well.    "The first job 
16 
Figure 24.?Rear crankcase cover and gear train: crankshaft 
gear drives B, which drives oil pump at F. A, integral with B, 
drives internal cam gear. B also drives C on fuel-circulating 
pump. D, driven by crankshaft gear, drives E on generator 
shaft.    U.S. Navy test, 1931.    (Smithsonian photo A48325C.) 
I ever did on the Towle was to patch the holes in the top and bottom of 
the hull when a cylinder blew off during run-up and nearly beheaded the 
pilot." 13 
Crankshaft: Since this engine developed the high maximum cylinder 
pressure of 1500 psi, it was necessary to protect the crankshaft from the 
resulting heavy stresses. Without such protection the crankshaft would be 
too large and heavy for practical aeronautical applications.   Although the 
13
 Letter, Richard Totten to National Air Museum, January 28, 1964. 
17 
Figure 25.?Master and link connecting 
rods. U.S. Navy test, 1931. (Smithsonian 
photo A48323A.) 
Figure 26.?Crankshaft with automatic- 
timing retarding device on rear end of 
pivoted- and spring-mounted counter- 
weights. U.S. Navy test, 1931. (Smith- 
sonian photo A48323B.) 
Figure 27.?Propeller hub and vibration damper.     U.S. Navy test, 1931 
(Smithsonian photo A48325A.) 
18 
maximum cylinder pressures were 10 times as great as the average ones, 
they were of short duration. The method of protecting the crankshaft took 
full advantage of this fact. It consisted of having the counterweights 
flexibly mounted instead of being rigidly bolted, as was common practice. 
The counterweights were pivoted on the crank cheeks. Powerful compres- 
sion springs absorbed the maximum impulses by permitting the counter- 
weights to lag slightly, yet forced them to travel precisely with the crank 
cheeks at all other times. 
Propeller Hub: The propeller is, of course, subject to the same stresses 
as the crankshaft. Instead of being rigidly bolted to the shaft as was 
common practice, it was further protected from excessive acceleration 
forces by being mounted in a rubber-cushioned hub. This permitted the 
use of a lighter propeller and hub. 
Valves: A further weight saving resulted from the use of a single 
valve for each cylinder instead of two as in the case of conventional gasoline 
aircraft engines. (A diesel engine designed in this manner loses less effi- 
ciency than a gasoline one because only air is drawn in during the intake 
stroke.) In addition to the weight saving brought about by having fewer 
parts in the valve mechanism, there was an additional advantage since the 
cylinder heads could be made considerably lighter. 
Figure 28.?Cylinder disassembly, show- 
ing valve and fuel injector. U.S. Navy 
test, 1931.   (Smithsonian photo A48324D.) 
19 
Diesel Cycle Features 
Although Woolson designed the ingenious weight-saving features, 
Dorner was responsible for the engine's diesel cycle which employed the 
"solid" type of fuel injection. In order to understand Dorner's contribu- 
tion, a brief description of the type of diesel injection pioneered by Dr. 
Rudolf Diesel is necessary. His system injected the fuel into the cylinder 
head with a blast of air supplied by a special air reservoir at a 
pressure of 1000 psi or more. Known as the "air blast" type of injection 
it produced good turbulence, with the fuel and air thoroughly mixed before 
being ignited. Such mixing increases engine efficiency, but it involves 
the provision of bulky and costly air-compressing apparatus which can 
absorb more than 5 percent of the engine's power. Naturally the com- 
pressor also adds considerably to the engine's weight. 
In contrast to this, a "solid" type of fuel injection may be employed to 
eliminate the complications of the "air blast" system. It consists of injecting 
only fuel at a pressure of 1000 psi or more. Air is admitted by intake stroke, 
as with a gasoline engine. Turbulence is induced by designing the com- 
bustion chamber and piston so as to give a whirling motion to the air during 
the intake stroke. The following quotation from Dorner now becomes 
readily understandable. "Since 1922 my invention consisted in eliminating 
the highly complicated compressor and in injecting directly such a highly 
diffused fuel spray so that a quick first ignition could be depended upon. 
By means of rotating the air column around the cylinder axis, fresh air was 
constantly led along the fuel spray to achieve completely sootless burning- 
up ... .   In 1930 I sold my U.S.A. patents to Packard." 14 
Valve Ports: The inlet port (which was also the exhaust port) was 
arranged tangentially to the cylinder. This design imparted a very rapid 
whirling motion to the incoming air, thereby aiding the combustion process. 
Engine efficiency and rpm were both increased. 
Fuel Injector Pumps : A combination fuel pump and nozzle was provided 
for each cylinder in contrast to the usual system of having a multiple pump 
unit remotely placed with regard to the nozzles. The former system was 
adopted after frequent fuel-line failures were experienced due to the engine's 
vibration. Woolson stated that his system prevented pressure waves, which 
interfered with the correct timing of the fuel injection, from forming in the 
tubing. Leigh M. Griffith, vice president of Emsco Aero, writing in the 
September 1930, S.A.E. Journal stated:  "Regarding the superiority claim 
14
 Letter, Hermann I. A. Dorner to National Air Museum, December 16, 1961. 
20 
? 
Figure 29.?Fuel-injector disassembly.    U.S. Navy test, 1931. 
(Smithsonian photo A48323C.) 
for the simple combination of fuel pump and injection valve into one unit, 
without connecting piping, the author entirely overlooks the fact that the 
elasticity of a pipe and its contained fuel can be important aids in securing 
that extremely abrupt beginning and ending of injection which is so 
desirable." 
A major advantage obtained from combining the fuel pump and 
injection valve is the ability of an engine so equipped to burn a wide variety 
of fuels. The elimination of the above-mentioned type of high-pressure 
tubing reduces the possibility of a vapor lock occurring, thereby permitting 
more volatile fuels to be burned. This increases the range of hydrocarbon 
fuels the engine can utilize. It could run on any type of hydrocarbon 
from gasoline to melted butter.16 
Another reason for combining the fuel pump and injection valve is given 
by P. E. Biggar in Diesel Engines (published in 1936 by the Macmillan Com- 
pany of Canada Ltd., Toronto) : "In the Dorner pump, for example, the 
stroke of the plunger is changed by using a lever-type lifter and moving the 
push-rod along the lever to vary its movement. Unfortunately, in all 
arrangements of this sort, the plunger comes to a reluctant and weary stop, 
as the roller of the lifter rounds the nose of the cam. When the movement 
does finally end, the injection does not necessarily stop, as the compressed 
fuel in the injection pipe is still left to dribble miserably into the combustion 
15
 The National Aeronautic Magazine (April 1932), vol. 10, no. 4. p. 18. 
21 
Figure 30.?Mechanism for retarding 
valve and fuel-injection timing during 
starting (see alsofig. 26). U.S. Navy test, 
1931.    (Smithsonian photo A48324E.) 
Figure 31,?Upper?valve and fuel 
injector cam; lower?fuel-injector cam 
used for starting. U.S. Navy test, 1931. 
(Smithsonian photo A48325.) 
chamber.   To minimize this defect, the designer has placed the pump and 
injector together in a single unit." 
Starting System: On November 1, 1961, C. H. Wiegman, vice presi- 
dent of engineering of the Lycoming Division of Avco Corporation wrote 
to the Museum in part as follows : 
Early in the development it became quite evident that cold starting was 
a problem. This was finally worked out by Packard through the use of glow 
plugs and speeding up the injectors during the cranking period.   It had been 
22 
felt that during the slow cranking process we were not vaporizing the fuel 
through the nozzles and that if we could speed up the injection pumps during 
this period of cranking a better vaporization could be obtained. Our tests 
showed that we were right, and that the engine could be started quite easily 
at minus 10? F through the use of glow plugs. The method used for speeding 
up the injection pumps was accomplished by utilizing a crankshaft cam during 
the cranking period. The starter would shift the running cam out of position 
allowing the crankshaft cam to take over. After the engine fired, the starter 
was disengaged and the running injector pump cam would assume its original 
position. The starting cam would be run at engine speed during cranking, 
and the running cam at }{ reverse engine speed during engine operation. 
The shifting was accomplished by a pin-in-slot and spring arrangement to 
change the indexing of the cams to starting position and returns 
An Eclipse electric starter with an oversized flywheel was used.    .    .    . 
This was powered by a double-sized battery. 
Development 
Air Shutters: The first engines had no provision for throttling the 
intake air. This allowed the engine to run on its own lubricating oil when 
the throttle was in idle position. As a result trie engine idled too fast, 
thereby causing either excessive taxiing speeds or rapid brake wear. This 
inability to idle slowly also caused high landing speeds since the propeller 
did not turn slowly enough to act as an airbrake. Figure 1 shows the first 
model. Note that the tubular air intakes on top of the cylinders have no 
valves. Figure 32 shows a later model. Note the butterfly valves in the 
U-shaped air intakes. Here they are shown fully opened. When the 
throttle was placed in idle position these valves automatically closed and 
prevented air from flowing past them. Air could then only enter from 
the back of the intakes. Since less air could flow into the cylinders, the force 
of their explosions was reduced, which, in turn, lowered the idling revolu- 
tions per minute. Figure 28 shows a cylinder from a more advanced model. 
Note the circular opening between the air intake and the intake/exhaust 
housing. A barrel type of valve fitted into this opening. One of these valves 
can be seen just below and to the left of the cylinder. When the throttle was 
placed in idle position this valve rotated to a position which cut off almost all 
of the airflow into its cylinder. This increased the vacuum formed toward 
the end of the intake stroke, thereby causing more resistance, which reduced 
the idling rpm to that of a gasoline engine.16 
?? Aviation (May 1931), vol. 30, no. 5, p. 281. 
23 
Figure 32.?Front left view of engine 
from Packard Motor Car Co. 50-hour 
test, 1930, showing butterfly valve type 
venturi throttles. (Smithsonian photo 
A48325E.) 
Figure 33.?Front left view of engine 
from U.S. Navy test, 1931, showing 
spiral oil cooler. (Smithsonian photo 
A48324A.) 
Crankcase: It was strengthened by having external ribs added. Note 
the contrast between the first engine, figure 2, and a later model, figure 32. 
Oil Cooler: The drum-shaped honeycombed cooler was replaced by 
a spiral pipe type located between the engine cowl and the crankcase. 
Figure 3 shows an example of the former type of cooler located at the top 
of the engine between two of the cylinders. Figure 33 illustrates the latter 
type located between the cowling and the crankcase. 
Cylinder Fastening: Early models had their cylinders strapped and 
bolted to the crankcase. Later ones had them only strapped. Figure 2 
shows a bolt-fastened clamp between two of the cylinders on the first engine. 
Figure 19 shows a later model without any bolts holding down the cylinders. 
Pistons: The pistons used in the 1929 engine had one compression ring 
and one oil scraper ring above the piston pin, and one oil scraper ring 
24 
Figure 34.?Modified pistons after 
endurance run. U.S. Navy test, 1931. 
(Smithsonian photo A48325D.) 
below it. There were three grooves, iwo above the piston pin, and one 
below it.17 Pistons used in 1930 had two compression rings, one oil scraper 
ring above the piston pin, and one oil scraper ring below it. There were 
four grooves, three above the piston pin, and one below it.18 The 1931 
pistons had one compression ring above the piston pin, and one compression 
ring and four oil scraper rings below it. There were four grooves, one above 
the piston pin, and three below it.19 
Combustion Chamber: In 1931 the contour of the cylinder head was 
changed slightly. This improved the combustion efficiency to the extent 
that the stroke of the fuel pumps could be decreased about 15 percent: 
The specific fuel consumption then decreased about 10 percent. In 
addition the compression ratio was reduced from 16:1 to 14:1.20 
These changes were designed to eliminate smoke from the exhaust at 
cruising speed, and to reduce it at wide-open throttle. 
Valves : A two-valve-per-cylinder model was built, but not put- into pro- 
duction. It featured more horsepower (300), a higher rate of revolutions per 
minute (2000), and a better specific fuel consumption (about .35 lb/hp/hr).21 
17
 The Packard Diesel Aircraft Engine, p. 5 
18
 Instruction Book for the Packard-Diesel Aircraft Engine, p. 3. 
19
 "Test of Packard-Diesel radial air-cooled engine," Navy Department, Bureau of 
Aeronautics, Report AEL-335, July 13, 1931, Bu. Aer. Proj. 2265. 
20
 Aviation (May 1931), vol. 30, no. 5, p. 281. 
21
 Letter, Clarence H. Wiegman to National Air Museum, November 1, 1961. 
25 
Capt. Woolson designed the production model with a single large valve for 
each cylinder. This was done in order to shorten the development period, 
for it is easier to design a single valve which serves both the intake and 
exhaust functions than one valve for each function. Not only are there 
fewer parts, but more important, there are no heat-dissipating problems. 
Although the single valve is heated when it releases the exhaust gases, it is 
immediately cooled by the incoming air of the next cycle. This cooling 
advantage is not shared by a valve which only passes exhaust gases.22 
Cylinder Head: Ribs were added to increase its rigidity (compare 
fig. 32 with fig. 33). 
Engine Size: A 400-hp model was developed in 1930. It was not 
put into production.23 
22
 Letter, Dorner to National Air Museum, January 15, 1962. 
23
 Letter, Hugo T. Byttebier to National Air Museum, October 20, 1961. 
26 
Comments 
Comments of Aeronautical Engineers: These comments appeared in 
Aviation for February 15, 1930, just a month before the Packard diesel 
received its appro ved-type certificate. They were in answer to the question, 
"What is your opinion of the probable early future of the compression 
ignition type of engine in aircraft powerplants?" Most of the engineers were 
enthusiastic about the diesel engine's future in aviation; however, neither 
George J. Mead nor C. Fayette Taylor shared their colleagues' opinions. 
Mead's prophesy was accurate except for his discounting the diesel's role in 
lighter-than-air craft. Taylor was correct in implying that there was a 
future for the diesel in powering airships. 
George J. Mead (vice president and technical director, Pratt & 
Whitney Aircraft Company) : 
Compared with the present Otto cycle engine, the Diesel powerplant 
weight, including fuel for a long-distance flight, would apparently be less. It is 
doubtful whether there would be any saving if the orthodox engine were 
operated on a more suitable fuel. Inherently the Diesel engine must stand 
higher pressures and therefore is heavier per horsepower. A partial solution 
of this difficulty is the two-cycle operation, which seems almost a requirement 
if the Diesel cycle is to be considered at all for aircraft. For any normal com- 
men?ai operation in the United States there seems to be little or no improve- 
ment to be had from the Diesel. After all, it is not entirely a question of fuel 
cost but payloads carried for a given horsepower. It seemed at one time as 
though the Diesel was particularly desirable for Zeppelin work. Now that 
blau gas has been introduced, which obviates the need of valving precious 
lifting gas, the Diesel cycle seems much less interesting for this purpose. There 
may be a reduction in fire hazard and radio interference with the Diesel cycle, 
but it is doubtful whether it will be used in view of these considerations alone. 
C. Fayette Taylor (professor of aeronautical engineering, Massachu- 
setts Institute of Technology) : "I believe that the compression ignition 
engine will continue to remain in the experimental stage during the year 
1930. I should expect its first really practical installation to be in lighter- 
than-air craft." 
27 
P. B. Taylor (acting chief engineer, Wright Aeronautical Corporation) : 
"I believe the compression ignition engine is probably the type which will 
eventually supersede the present electric ignition units. This development 
will come slowly and will not be a solid injection engine." 
Henry M. Mullinnix (former chief of powerplant section, Navy Bureau 
of Aeronautics) : 
The advantages of compression-ignition, including reduced fire hazard, 
more efficient cycle, elimination of electrical apparatus and hence of radio 
interference, elimination of carburetion problems, and other benefits less evi- 
dent, would seem to outweigh the difficulties encountered in metering and 
injecting minute quantities of fuel at the proper instant. Although the 
Diesel engine suffers upon comparison with the Otto cycle engine in flexi- 
bility there seems to be a definite field for employment of Diesels and a gradual 
extension of their use may be predicted. 
John H. Geisse (chief engineer, Comet Engine Corporation) : "I am 
firmly convinced that the Diesel engine in the future will not only maintain 
the advantages of Diesel engines as they are now known, but will also be 
lighter in pounds per horsepower than the present Otto engines." 
Lt. Cdr. C. G. McCord (U.S. Navy, Naval Aircraft Factory): "The 
use of compression ignition in due time appears to be assured ; but increase 
in weights above those of present Otto cycle engines, to insure reliability, 
must be expected." 
L. M. Woolson (aeronautical engineer, Packard Motor Car Com- 
pany) : "There is no question that the compression ignition aircraft engine 
will in time offer severe competition to the gasoline engine. There are, 
however, many basic problems to be solved for the solution of which there 
exists no precedent." 
N. N. Tilley (chief engineer, Kinner Airplane and Motor Corp.) : 
Considerable development of the compression ignition type of engine for 
aircraft will be required before it is commonly available. It is believed that 
the weight per horsepower must be equal to, or less than, that of the present 
type of engines, in order to interest the public, since rapid take-off, rate of 
climb, and speed are desired, rather than low fuel consumption or high mileage. 
Most flights are of few hours duration. It is believed that flights must be of 
over five or six hours duration in order to show any advantage of Diesel engines 
(with low fuel consumption) if appreciably heavier than present engines. 
Also the difference between Otto cycle and Diesel becomes slight as the 
compression ratios come closer together. 
Comments of Flight Crews : The preceding comments were made by 
engineers thinking primarily of the commercial possibilities of the diesel. 
Following  are comments  by  flight  crewmembers  about  the operating 
28 
characteristics of the Packard diesel. The former were largely optimistic. 
Most of them were only familiar with the aeronautical diesel as a design 
project and therefore did not have the practical experience necessary to 
understand all of its limitations. The latter were pessimistic, as they knew 
firsthand various shortcomings of the engine which only became apparent 
when it was operated. 
Clarence D. Chamberlin, pioneer pilot: 
My only experience with the Packard diesel was in a Lockheed "Vega" 
which I owned back about 1932. The Wright J-5 had been replaced with the 
225 hp Packard Diesel. My main complaint was the excessive fumes. When 
I would come home at night my wife would greet me with, "You have been 
flying that oil burner again." It was so bad that passengers' clothing would 
smell like a smoky oil stove for hours after a flight. 
Looking backward, it is my guess that the Diesel would have had only a 
limited period of acceptance even if all mistakes had been avoided. It is 
easier and cheaper to get performance with lighter and more powerful engines 
and longer runways than by refining the airplane. Fuel economy of an engine 
has ceased to be the deciding factor. Higher utilization of a high speed Jet at 
least in part offsets the inefficient use of fuel. The only time the Diesel had a 
chance was from the middle 20's perhaps on thru WW-2 for certain things due 
to gasoline shortage. To sum it up, the thing that licked them worst was 
the use of a single valve for inlet and exhaust making it impossible to collect 
and keep the fumes out of the fuselage.24 
Ruth Nichols, prominent aviatrix : 
I was flying Chamberlin's diesel-powered Lockheed, in which a month 
before I had made an official altitude record for both men and women in air- 
craft powered by an engine of that type. The record, I believe, still holds. 
It was a rugged, dependable plane whose experimental oil-burning engine 
nevertheless had a number of bugs. For one thing, it was constantly blowing 
out glow-plugs used for warming the fuel mixture, and when that happened 
long white plumes of smoke would stream out, giving spectators the impression 
that the ship was on fire. For another, the vibration was so bad that out of 10 
standard instruments on the plane, 7 were broken from the jarring before my 
return. The diesel fuel also produced a strong odor in the cockpit, the fumes 
so permeating my luggage and clothes that my public appearances during the 
tour always were highly and not very agreeably aromatic. Having a strong 
stomach, I soon became accustomed to the fumes, but another pilot who ferried 
the plane between cities for me on one occasion . . . was almost overcome. 
On arrival he said, "I wouldn't fly that oil burner another mile." 25 
24
 Letter, Clarence D. Chamberlin to National Air Museum, February 8, 1964. 
25
 RUTH NICHOLS, Wings For Life (Philadelphia and New York: J. B. Lippincott Co., 
1957), p. 205. 
29 
% 
U 
^%s 
?     ^^~ 
4$* > 
^1   K Itiwm. 
Mr" 
^???k *t 
? 
Figure 35.?Ford 11-AT-1 Trimotor, 1930, with 3  Packard 225-hp  DR-980 diesel 
engines,  right side view of right engine nacelle.     (Smithsonian  photo A48311.) 
Richard Totten,26 airplane mechanic: 
The Ford Trimotor was the poorest of the lot. It was inherently noisy and 
slow, and with the Packards installed it was on the point of being under- 
powered. It was almost impossible to synchronize the three engines, and the 
beat was almost unbearable. It was not flown much but it made a fine con- 
versation piece standing on the airport apron. . .  . 
The Waco taperwing developed the unnerving habit of breaking flying and 
landing wires from the vibration, and most of the time sat on the hangar floor 
with its wings drooping like a sick pigeon. In flight the open cockpit filled with 
exhaust smoke and unburned fuel and the pilot would land after an hour's 
flight looking like an Indianapolis 500 Mile Race driver. . . . 
The Stinson "Detroiter," the Bellanca "Pacemaker" and the Buhl- 
Verville "Airsedan" were the most successful ships and were the most used. 
The "Airsedan," in which Woolson was killed, was his favorite ship, and the 
one I believe that was the most flown. 
26
 Letter, Richard Totten to National Air Museum, January 28, 1964. 
30 
The Towle TA-3 amphibian flew beautifully, but not for long. It never 
got a chance to do much as it was a victim of the depression. The Towle was 
powered by 2 Packard diesels on loan from the Packard Motor Car Com- 
pany. It was built of corrugated aluminum exactly like the Ford Trimotor. 
As a matter of fact, Towle had been employed by Ford until Ford cancelled 
airplane building. Towle got his airplane built at the hangar on Grosse Isle 
in Detroit, and ran out of money during the flight testing program. He now 
looked for money to continue with and found a backer in the person of one 
Doctor Adams, a widely advertised "Painless Dentist" of Detroit. Adams 
wanted a quicker return on his money than the average backer and he in- 
sisted that Towle put the airplane in service so it could start earning some 
money. At this time the amphibian was beginning to become popular for 
intercity flying, especially around the Great Lakes region as all of the major 
cities were located on the waterfront. What was more natural than an airline 
flying passengers right into the downtown area of a city? Thompson was 
doing it between Detroit and Cleveland, Marquette was doing it between 
Detroit and Milwaukee, so Adams applied for permission to operate an air- 
plane between Detroit and Cleveland and other cities on the lakes. In those 
days it was necessary to prove an airplane's reliability by flying a certain num- 
ber of trips over the proposed route with a simulated payload. This payload 
was supposed to consist of sand bags, but usually consisted of any mechanic 
or pilot who happened to be loose at the moment, and who had nerve enough 
to go along.   Mechanics were easier to load and unload than sand bags. 
The Towle was in the middle of the qualification flights, and the publicity 
began to appear about the new airline. Much newsprint was devoted to the 
fact that the Towle was powered by the new Packard diesel engine, and this, 
of course, made it the only safe airline since all its competitors were using the 
old-fashioned dangerous gasoline. On the last payload trip of the Towle 
the pilot asked me if I wanted to go along, and of course I was delighted. I 
neglected to mention that I had been hired by the Adams airline as a mechanic 
because of my experience in repairing the corrugated skin of the Ford Tri- 
motor owned by my employer, the Knowles Flying Service. The mere fact 
that I did many repairs to the airframe did not preclude me from getting my 
share of the engine work too, and since I was already familiar with the Packard 
diesel, I was quickly hired by Dr. Adams. 
The last flight was indeed the last flight. We took off from the Detroit 
City Airport and when we crossed the Detroit river the pilot decided to land 
at the Solvay Coal Company docks and fuel up for the opening of the airline 
the next day. The Solvay Coal Company was the only place in Detroit where 
diesel fuel was obtainable at the time and all of the diesel powered yachts 
got fuel there. The pilot was not too experienced in the operation of am- 
phibians, and he put the wheels down as we approached the river. When we 
hit the water the airplane went over on its back and sunk to the bottom.   It 
31 
came up to the surface again, and we all climbed out onto the keel, and waited 
for rescue. A police boat came over and took us to the dock. The police sent 
us to the hospital and then went back and towed the airplane over to the 
shipyard next door to Solvay. While we were at the hospital, the crane man 
hooked onto the Towle and lifted it out of the water and gently set it down on 
the dock. He was only trying to help, but he inadvertently set it down on its 
back instead of its wheels. That was the end of the Adams airline. The 
Packard Company took back their engines. I helped remove them the next 
day. We dismantled the airplane and trucked it back to the airport where it 
sat in a state of neglect for some time. The pilot was fired, I lost my job, and 
Towle lost his airplane. 
32 
Analysis 
Advantages 
A Packard diesel advertisement which appeared in Aero Digest for 
June 1930 stated that this engine had three major advantages over its 
gasoline rivals : Greater reliability because of extreme simplicity of design ; 
greater economy because of lower fuel cost plus lower fuel consumption, 
permitting greater payloads with longer range of flight; and greater safety 
because of removal of the fire hazard through the use of fire-safe fuel and 
absence of electrical ignition equipment. 
These were the engine's principal advantages. Others are analyzed 
here by the author in order of their importance. At low altitudes the diesel 
uses an excess of air to eliminate a smoking exhaust; consequently at 
high altitudes, where the air is less dense, the diesel is still able to maintain 
much of its power. In contrast, the carburetored gasoline engine is sensitive 
to the fuel-air ratio and thus has no surplus air available at higher altitudes. 
A malfunctioning carburetor could cause a gasoline engine to cease operat- 
ing, but an inoperative fuel injector would cause the Packard diesel to lose 
one ninth of its power, since each cylinder had its own independently 
operating injector. In practice, however, because of the excessive vibra- 
tion, the engine was generally shut off immediately after a cylinder cut out.27 
Shielding was unnecessary because the diesel had no electrical ignition 
system. Carburetor icing was an impossibility because there was no 
carburetor. 
Any excess lubricating oil in a diesel engine's cylinder is consumed 
cleanly to produce power. By contrast, such oil in a gasoline engine's 
cylinder is only partly burned. As a result carbon deposits form that 
eventually cause malfunctioning of the spark plugs, valves, and combustion 
chambers. This advantage accrued to the diesel because it utilized an 
excess of air, and in addition its cylinder walls were hotter. The engine 
was very clean-running from the standpoint of oil leakage. This was a 
safety factor since it eliminated the possibility of a fire starting on the out- 
side surfaces of the engine, and in addition it saved the time and money 
27
 Letter, Richard Totten to National Air Museum, January 28, 1961. 
33 
The 
PACKARD-DIESEL 
AIRCRAFT ENGINE 
fire-Safe 
fue 
But only when 
properly atomized 
the spray may be 
iqnited 
Graphic Proof 
of fuel safety 
in the 
Packard-Diesel 
Aircraft fnqine 
Figure 36.?Advertisement emphasizing the advantages of fire-safe fuel 
(Smithsonian photo A48848.) 
34 
that was normally spent cleaning engines.28 Since the diesel utilized its 
heat of combustion more efficiently than the gasoline engine, its cooling 
fin area could be reduced by 35 percent. This permitted better stream- 
lining. Having less cooling fin area, it warmed up more rapidly than a 
gasoline engine. 
Due to the greater simplicity, it was more practical to build a large diesel 
than a large gasoline engine. Large airplanes would therefore need fewer 
engines if diesel powered. Smaller fuel tanks could be used because of the 
greater fuel economy of the diesel, and also because of the high specific 
gravity of fuel oil as compared to gasoline. Furthermore, these smaller 
tanks could be placed in more convenient locations. Not having a carbu- 
retor the engine could not backfire, further reducing the fire hazard. The 
exhaust note was lower because of the diesel's higher expansion ratio. The 
absence of an ignition system permitted the diesel to operate in the heaviest 
types of precipitation. Such conditions might cause the ignition system of a 
gasoline engine to malfunction. The Packard diesel was flown at times 
without exhaust stacks or manifolds; this was practical from a safety 
standpoint because of the diesel's lower exhaust temperature due to its 
higher expansion ratio. Elimination of these parts reduced the weight and 
cost of the engine installation. Finally, the engine was ideal for aerobatics, 
since the injectors, unlike carburetors, would work equally well whether 
right side up or upside down. 
An advantage peculiar to the Packard among aeronautical diesels was 
its light weight. The English Beardmore "Tornado III" weighed 6.9 lb/hp, 
and the German Junkers SL-1 (FO-4) weighed 3.1 lb/hp, while the Packard 
weighed but 2.3 lb/hp. In fairness to the Beardmore, it was the only one 
of the three engines designed for airship use, and part of its heaviness was 
due to the special requirements of lighter-than-air craft. A contemporary 
and comparable American gasoline engine, the Lycoming R-680, weighed 
2.2 lb/hp. To have designed a diesel aircraft engine as light as a gasoline 
one was a remarkable achievement. 
Disadvantages 
There are four main reasons why the Packard diesel was not successful. 
First the Packard Motor Car Company put the engine into production a 
brief three years after it was created. The only successful airplane diesel, 
the German Junkers "Jumo," was in development more than three times 
Aero Digest (February 1931), vol. 18, no. 2, p. 58. 
35 
as long (1912-1929).   The following tests indicate that the Packard diesel 
was not ready for production, and hence was unreliable. 
Packard Motor Car Company 50-Hour Test (Feb. 15-18, 1930) : This 
test was identical to the standard Army 50-hour test which was used for the 
granting of the Approved Type Certificate. The engine tested was num- 
bered 100, and was the first to be made with production tools (approxi- 
mately half a dozen engines had been handmade previously). It had to be 
stopped three times, twice due to failure of the fuel pump plunger springs 
and once due to the loosening of the oil connection ring. These failures 
were attributed to manufacturing discrepancies. In addition, 4 out of a 
total of 103 valve springs broke.29 
U.S. Navy 50-Hour Test (Jan. 22, 1931, to March 15, 1931): The 
engine used in the Navy test was numbered 120. (Apparently only 20 
production engines had been built during the preceding 12 months; 
Dorner in a letter of March 3, 1962, states that the total number of Packard 
diesels produced was approximately 25.) The engine had to be stopped 
three times, twice due to valve-spring collar failures and once due to a 
valve head breaking. Because of these failures this test was not completed. 
The following significant quotations have been extracted from the test: 
"The engine is not recommended for service use .... Flight tests, until 
the durability of the engine is improved, be limited to a determination of the 
critical engine speeds, and to short hops in seaplanes .... It is believed 
that this size engine should be made suitable for service use before this type 
in a larger class is attempted." This latter statement probably refers to 
the 400-hp model. 
A year had passed between the making of engine 100 and 120, yet the 
reliability had not improved. Although unreliability was the immediate 
cause of failure, there were two design defects which would have doomed 
the engine even if it had been reliable. All the Packard diesels were of 
the 4-stroke cycle unblown type, yet the most successful airplane diesels 
were of the 2-stroke cycle blown type.30 The advantages of the latter 
type for aeronautical use are that is is of a more compact engine, of lower 
29
 "50-Hour Test of Packard Diesel Aircraft Engine," Packard Motor Car Company, 
Detroit, Michigan, serial no. 426, test no. 234-73, February 19, 1930. 
30
 Blower in this sense refers to a low-pressure air pump (supercharger) designed to 
increase cylinder scavenging efficiency by blowing out exhaust gasses. In doing this it 
also increases somewhat the amount of fresh air introduced into the cylinders. Woolson 
invented a 2-stroke cycle blown engine; the patent was issued in 1932 (patent 1853714) 
with rights assigned to the Packard Motor Car Company. (Woolson himself died in 
1930.) 
36 
weight and greater efficiency.31 The engine was therefore built around 
the wrong cycle. 
The Packard diesel of 1928 was designed to compete with the Wright 
J-5 "Whirlwind" which powered Lindbergh's "Spirit of St. Louis" in 1927.32 
The specifications were within two percent of each other. The diesel en- 
gine's fuel consumption was far less although its price was considerably 
higher. 
Packard Diesel Wright J-$ 
DR-98o "Whirlwind" 
Diameter (in.)     45%  45 
Horsepower     225  225 
Weight (lb)     510  510 
Weight-horsepower ratio     2.26  2.26 
Fuel  consumption   (lb  per  hp/hr  at    0.40  0.60 
cruising). 
Cost     $4025  .. . $3000 
The advantages of lower fuel cost and greater cruising range offered by 
the diesel engine would be relatively unimportant to a private pilot flying 
for pleasure, but would be vital to the commercial operator using air- 
planes powered by engines having several times the horsepower of the 
Packard diesel. Its size, moreover, was too small for the technology of 
fuel injectors.33 The Packard Company realized that the production engine 
was too small.34 In 1930 a 400-hp version was built but was not put into 
production, probably because of the unreliability of the 225-hp model. 
The fourth principal reason why the engine failed is explained by the 
following quotation from The Propulsion of Aircraft, by M. J. B. Davy (pub- 
lished in 1936 by His Majesty's Stationery Office, London): 
Although the development and adoption for transport purposes of the 
relatively high-speed compression ignition engine has been rapid during the 
last few years, there has been no corresponding advance in its adoption for air- 
31
 A 2-stroke cycle engine completes 360? of crankshaft rotation in what it takes a 4- 
stroke cycle engine 720? to accomplish. A 3-cylinder two-stroke cycle engine therefore 
has the same capacity to do work as a 6-cylinder four-stroke cycle engine. For this reason 
the former type of engine is both more compact and lighter than the latter type. 
The above advantages, plus the increased efficiency of the blown 2-cycle diesel, are 
discussed in Flight?The Aeronautical Engineer Supplement (December 26, 1940), vol. 19, 
no. 11, pp. 545 and 552. 
32
 Packard advertisement?Aero Digest (June 1930), vol. 16, no. 6, p. 23. 
33
 Aviation (March 15, 1930), vol. 28, no. 11, p. 531. 
34
 The National Aeronautic Magazine (April 1932), vol. 10, no. 4., p. 18. 
37 
craft propulsion. A reason for this is the recent great advance in "take-off" 
power in the petrol (gasoline) engine due to the introduction of 87 octane 
fuel (which permits higher compression ratios) and the strong probability of 
100 octane fuels in the near future, still further increasing this power. The 
need for increased take-off power results from the higher wing loading necessi- 
tated by the modern demand for commercial aircraft with higher cruising 
speeds with reasonable power expenditure. 
Production of the Packard diesel ceased in 1933. During that same 
year the Pratt & Whitney Aircraft Company and the Wright Aeronautical 
Corporation specified 87-octane fuel for certain of their engines. Less than 
10 years later octane ratings had increased to over 100, putting the diesel 
at a further disadvantage.35 
Although the above disadvantages sealed the Packard diesel's fate, there 
were other minor reasons for its failure. The Packard diesel had the highest 
maximum cylinder pressure (up to 1500 psi at peak rpm) of any proven 
contemporary aircraft diesel engine. Leigh M. Griffith, vice president and 
general manager, Emsco Aero Engine Company, had this to say about the 
Packard diesel's high maximum cylinder pressure in the September 1930 
S.A.E. Journal: 
The designers considered it necessary to adopt unusual but admittedly 
clever expedients to counteract the great torque irregularity caused by the 
excessive maximum pressure. The adoption of the lower pressure of 800 lbs. 
would have eliminated the necessity for the pivoted spring-mounted counter- 
weights and the shock-absorbing rubber propeller-drive .... The use of 
such high pressures is in reality the quick and easy way to secure high-speed 
operation and can be justified only from this standpoint, although the resulting 
increased difficulty in keeping the engine light enough was a strong offsetting 
factor.36 
Insofar as the engine life was concerned it is true that 1,500-psi peak 
pressures were observed but the engine was so developed to withstand these 
pressures .... One of the most severe problems connected with the develop- 
ment of this engine was the piston ring sealing. Special compression rings 
were made with no gaps and further work in this respect could have been used 
to advantage had the engine been kept in production.37 
35
 Appendix, p. 47 
36
 See Woolson's patent 1794047, issued in 1931 and assigned to the Packard Motor 
Car Company. "An object of my invention is to automatically regulate the compression 
ratio in an engine inversely to the speed. . . ." See also his patent 1891321, issued in 1932 
and assigned to the Packard Motor Car Company. It describes a similar but nonauto- 
matic system. Woolson therefore fully realized the disadvantages of the high cylinder 
pressures his engine developed at high rpm's. 
37
 Letter, Clarence H. Wiegman to National Air Museum, November 1, 1961. 
38 
It is significant that in 1930 the Packard diesel had a compression ratio 
of 16:1, whereas in 1931 it has been reduced to 14:1. This was probably 
done to reduce vibration and the problem of piston-ring sealing.38 The 
exhaust products had an unpleasant odor which was particularly objec- 
tionable during taxiing. Professor C. Fayette Taylor, writing in the January 
1931 issue of Aviation, remarked about this fault: "One is inclined to 
question whether the disagreeable escaping of exhaust gas from the intake 
ports can be overcome, while still retaining the obvious advantages in weight 
and simplicity of the single valve." The engine exhaust deposited a black 
oily film. In fact some airplanes fitted with the Packard diesel engine were 
painted black, so that soot deposits from the exhaust would not be noticed.39 
Since the passengers' and pilots' compartments were generally located 
behind the engines, and were not airtight, damage to clothing resulted. 
This fault could have been eliminated by the use of separate valves for 
the intake and exhaust systems. 
It was not possible to start the engine when the temperature dropped 
much below 32? F unless glow plugs were used. These spark-plug-like 
devices, which were only used for starting, had resistance windings which 
glowed continuously when turned on. The additional heat glow plugs 
provided made starting an easy matter in the coldest weather ; however, they 
complicated the design of an engine noted for its simplicity, and they used so 
much electricity that only a long flight would allow the generator to fully 
recharge the battery. 
H. R. Ricardo, writing in the June 4, 1930, issue of The Aeroplane said: 
"Referring to the very fine achievement of the Packard Company of 
America in producing a small radial air-cooled heavy-oil engine, a petrol 
engine of similar design and with the same margin of safety would weigh 
less than 1% lbs. per hp." The important point made is that a gasoline 
engine designed along the same lines as the Packard diesel would weigh 
considerably less, but would then suffer from the Packard's reduced struc- 
tural safety factor. It is significant that as the Packard developed, it 
became heavier.40 
Like other diesels, the Packard cost more to build than a comparable 
gasoline engine, because of the type of construction required for the diesel's 
higher maximum cylinder pressures and the difficulty of machining the 
fuel injectors.   Having fuel injectors, the engine was more sensitive to 
38
 Ibid. 
39
 Major George E. A. Hallet, U.S. Air Service, former director of engineering division, 
McCook Field, Dayton, Ohio. 
40
 "Test of Packard-Diesel radial air-cooled engine," Navy Department, Bureau of 
Aeronautics, Report AEL-335, July 13, 1931, BuAer Proj. 2265. 
39 
dirt in the fuel system than a carburetor-equipped gasoline engine.41 The 
fuel injectors were "a crude and deficient mechanism" subject to rapid wear, 
and often these injectors caused smoking exhausts and high fuel consump- 
tions.42 In the event of battery or starter failure, a comparable gasoline 
engine could be started by swinging the propeller. Because of the engine's 
high compression, it would have been impossible to have hand-started a 
Packard diesel this way. 
In a letter to the Air Museum, January 15, 1962, Dorner commented: 
"During my first demonstration (of high-speed diesel engines) in 1926 in 
California and later in Detroit I learned from Gapt. Woolson that the large 
transport airlines were controlled by oil companies which were not interested 
in (supplying) two different kinds of aircraft fuel, and in savings of fuel." 
The May issue of Aero Digest had a full-page illustrated advertisement 
titled "Announcing National Distribution for Texaco Aerodiesel Fuel." 
Although distribution was limited, the American oil industry did not pre- 
vent the airplane diesel from becoming a success in the civil market. How- 
ever, it is significant that the advertisement was placed by Frank Hawks of 
the Texas Company largely as a gesture of friendship to Woolson.43 
The situation in the military market was different, however, as testified 
by this quotation from the same letter. "The military administration, 
having paid all of the expenses for the testing periori to that date (1931), 
came after the tests to the conclusion that the advantages of the diesel as 
compared to its disadvantages did not justify the great risk to procure and 
distribute two different kinds of fuel in case of war." 
Two accidents, which received wide publicity and no doubt did con- 
siderable harm to the entire project, occurred to Packard diesel-powered 
airplanes. The following quotation is from the Herald Tribune for April 23, 
1930: "Attica, New York?Losing their bearings in a blinding snowstorm 
and mistaking the side of a snow-covered hill for a suitable landing place, 
three men, one of them Capt. Lionel M. Woolson, aeronautical engineer for 
the Packard Motor Company and adapter of the diesel engine to airplanes, 
were killed here today." 
The second of these accidents is described in the September 1931 issue of 
U.S. Air Services: 
Columbus wanted to sail west beyond the limits set by the learned navi- 
gators of his time, and in much the same consuming fashion Parker D. Cramer 
41
 Aviation Week and Space Technology (February 19, 1962), vol. 76, no. 8, p. 101, 
42
 Aeronautics (October 1929), vol. 5, no. 4, p. 31. 
43
 Letter, Richard Totten to National Air Museum, January 28, 1964. 
40 
ma 
r& 
Figure 37.?Interior of Bellanca, showing Parker D. Cramer, pilot (left), and Oliver L. 
Paquette, radio operator, just before taking off from Detroit, Michigan, on July 28, 
1931.    (Smithsonian photo A202.) 
wanted to show his generation and posterity that a subarctic air route to 
Europe via Canada, Greenland, Iceland, Norway, and Denmark was feasi- 
ble .... On July 27, without any preliminary announcement, Cramer left 
Detroit in a Diesel-engined Bellanca, and following the course he took with 
Bert Hassel three years ago, he flew first to Cochrane, on Hudson Bay. His 
next stop was Great Whales and then Wakeham Bay. From there he flew to 
Pangnirtum, Baffin Land, and across the Hudson Straits to Holsteinborg, 
Greenland. He crossed the icecap at a point farther north than the routes that 
have been discussed heretofore, but almost on the most direct or Great Circle 
route from Detroit to Copenhagen. He was accompanied by Oliver Paquette, 
radio operator. They were on their way more than a week before they were 
discovered.   To Iceland, to the Faroe Islands, to the Shetlands. 
41 
They were taxiing across the little harbor of Lerwick, Shetland Islands, 
when a messenger from the bank waved a yellow paper. It was a warning of 
gales on the coast east to Copenhagen. Cramer apparently thought it was an 
enthusiastic bon voyage, and, after circling the town, flew away. A Swedish 
radio station reported a faint "Hello, Hello, Hello" in English, but the plane 
was not seen again. 
As the result of a personal conversation with his brother, William A. 
Cramer, in 1964, the author learned that the fuselage and floats of the 
airplane were found six weeks later. Since there was no indication of a 
heavy impact (not a single glass dial on the instrument panel was broken), 
a successful landing must have been made. Several weeks later, a package 
was found wrapped in a torn oilskin containing instruments, maps, and a 
personal letter, all substantiating the evidence that the landing was suc- 
cessful. It can only be surmised that there was engine failure, probably due 
to a clogged oil filter.44 
Once before during the trip a forced landing had been made due to 
engine malfunctioning, and a successful takeoff was accomplished in spite 
of a moderately rough sea. This time, however, storm conditions probably 
made the takeoff impossible. 
As a final summary of the author's analysis of the Packard diesel engine, 
it must be emphasized that although the engine burned a much cheaper 
and safer fuel more efficiently than any of its gasoline rivals, it was too 
unreliable to compete with them. Even if it had been reliable, it was too 
small to be useful to the large transport operators, to whom its fuel economy 
would have appealed. In addition, this mechanism operated on the 
wrong cycle: 4-stroke, rather than the lighter, more compact, and more 
efficient blown 2-stroke cycle. Lastly, it was doomed by the advent of 
high octane gasolines, first used while it was still in the development stage. 
These new fuels reduced the diesel's advantage resulting from low fuel 
consumption, and, in addition, gave the gasoline engine a definite advantage 
from the standpoint of performance. The Packard diesel was a daring 
design but, for the reasons analyzed in this chapter, it could not meet this 
competition, and therefore failed to survive. 
44
 According to Frederic E. Hatch of the National Air Museum, it is possible that the 
engine failed because the fuel injectors became clogged. He notes that the airplane 
refueled at several fishing ports, and therefore must have used diesel oil set aside for fishing 
boats. This oil was generally quite dirty. As a result it was routine for the fishermen to 
have to clean engine oil filters frequently enroute. The oil filters of the Packard diesel 
could not be cleaned in flight. 
42 
Appendix 
1. Agreement between Hermann I. A. Dorner and Packard 
Motor Car Company 
THIS AGREEMENT made this 18th day of August 1927, by and between HER- 
MANN DORNER, of Hanover, Germany, hereinafter referred to as "Licensor", and 
PACKARD MOTOR CAR COMPANY, a Corporation of the State of Michigan, United 
States of America, of Detroit, Michigan, hereinafter referred to as "Licensee" ; 
WITNESSETH, that 
WHEREAS, Licensor owns certain Letters Patent of the United States and 
other countries relating to oil burning engines under which he desires to license 
the Licensee; 
WHEREAS, Licensee desires rights under said Letters Patent; 
NOW, THEREFORE, for the mutual considerations hereinafter set forth, the 
parties have agreed as follows: 
1. Licensor warrants that he is the inventor of an oil burning engine, is the 
sole owner of United States patent Number 1,628,657, dated May 17, 1927, and 
United States patent applications, Serial Numbers 46,383 filed July 27, 1925, and 
88,409 and 88,411, filed February 15, 1926, relating to such engines and is joint or 
sole owner of patents or patent rights relating to said engines in England, Germany 
and Sweden. 
2. Licensor agrees to furnish the Licensee at cost price but not exceeding 
Thirty Dollars ($30.00) cash, as many pump and nozzle units as are needed for use 
in building one or more experimental engines. 
3. Licensor hereby gives and grants unto Licensee an exclusive license for 
the manufacture, within the United States and its dependencies, and a non- 
exclusive license for the use and sale, of engines for aircraft, and a non-exclusive 
license for the manufacture, use, and sale of engines for motor vehi?les and motor 
boats, under said United States patent Number 1,628,657, under all after-acquired 
patents and under all patents that may result from said patent applications, and 
from all other patent applications pertaining to his present oil burning engine 
or reasonable variations thereof, such licenses to extend for the full life and term of 
all such patents, provided however, that there is specially excepted from this 
grant?stationary engines, tractor engines, and engines for agricultural purposes. 
4. Licensor further hereby permits said Licensee to export to all other 
countries and sell and use there, without further royalty, all engines made by 
Licensee in the United States under this license. 
5. Licensor acknowledges receipt of One Thousand Dollars ($1,000.00) in 
43 
payment of a portion of the expenses heretofore incurred by him and as one of the 
considerations for this agreement. 
6. Licensor agrees to devote all time necessary from this date to November 
1, 1928 to supervision of the design of an engine and construction thereof at the 
plant of the Licensee and will in his absence furnish the services of a competent 
assistant, the expenses of Licensor and assistant to be paid for by Licensee at the 
rate of One Thousand Dollars ($1,000.00) per month for the first three (3) months, 
and Five Hundred Dollars ($500.00) per month thereafter until the decision in 
paragraph eight has been made by Licensee. 
7. Licensee agrees to build and test at least one experimental aircraft 
engine with special Dorner features, and to take all reasonable measures to reach 
the stage of final test. All Dorner feature engines made by Licensee will be 
marked "Licensed Under Dorner Patents." 
8. Within one year after the completion of tests of the aircraft engine 
built by Licensee hereunder, or in any event not later than November 1, 1928, 
Licensee will decide whether it will proceed with the manufacture of engines 
hereunder, or not. If Licensee decides in the affirmative then it will pay Licensor 
forthwith the sum of Five Thousand Dollars ($5,000.00) as advance on royalties 
and as minimum royalty for the first production year. If Licensee decides in the 
negative for reasons which are under the influence of Licensor, then Licensee will 
give Licensor notice and sufficient time to try to correct possible imperfections, and 
the time for final decision will be correspondingly extended. If the reasons for 
the negative decision are under the influence of Licensee, then Licensee will grant 
to Licensor an oral conference at Detroit and explain the reasons in detail. In 
event a negative decision is finally rendered by Licensee this agreement may be 
terminated at any time thereafter upon sixty (60) days' notice in writing to 
Licensee and both parties released from all further obligations hereunder. 
9. Licensee agrees that if after three (3) years from the date hereof Licensee 
is not manufacturing and does not contemplate the manufacture of, a certain size 
and type of aircraft engine which Licensor would like to grant another manufac- 
turer the right to build and which would not reasonably compete with anything 
manufactured by Licensee, Licensee will release such size and type aircraft engine 
from the exclusiveness of this license and thereby permit Licensor to grant a 
license to such other manufacturer to make, use and sell such engine and such 
engine only. 
10. Licensee agrees to pay royalty on all engines manufactured and sold or 
used under this agreement, based on effective brake horsepower under normal 
load, as follows: 
On each of the first Five Thousand (5,000) such engines produced 
and sold in any one calendar year, the royalty shall be at the rate of 
Twenty-five Cents ($.25) per horsepower; and on all over Five 
Thousand (5,000) in such calendar year, at the rate of Ten Cents 
($.10) per horsepower; 
44 
provided that, after a total of Fifty Thousand Dollars ($50,000.00) has been paid in 
royalties the royalties shall be reduced one-half (K). 
11. After the beginning of the second year of production, Licensee agrees 
that if the royalties under the above schedule amount to less than Ten Thousand 
Dollars ($10,000.00) per year then the royalty shall be Ten Thousand Dollars 
($10,000.00) per year payable in quarterly instalments of Two Thousand Five 
Hundred Dollars ($2,500.00) each, or in other words, the minimum royalty payable 
shall be Ten Thousand Dollars ($10,000.00) per year. 
12. Royalties shall continue only during the life of said patent Number 
1,628,657, and when a total of Two Hundred Fifty Thousand Dollars ($250,000.00) 
has been paid by Licensee to Licensor, all royalties shall cease and the license 
hereunder shall be free thereafter. 
13. Licensor agrees that Licensee shall have the benefit of any more favora- 
ble royalty rates that may be hereafter granted to or enjoyed by any other manu- 
facturer of engines other than aircraft engines. 
14. Licensee agrees to keep proper books of account showing the number 
of engines manufactured and sold or used under this agreement and to report 
quarterly to Licensor. 
15. In case of suit against the Licensee for infringement of patents by any 
of the Dorner features built under this license Licensor agrees to assist in the defense 
of any such suit and pay the expenses thereof up to an amount equal to Ten Percent 
(10%) of all royalties paid by Licensee to Licensor hereunder. 
16. In event of default of the Licensee in the payment of any of the sums 
herein provided for, Licensor may terminate this license agreement by serving 
upon the Licensee Sixty (60) days' notice in writing of its desire and determination 
so to do and stating the default upon which the notice is based, and at the expira- 
tion of such Sixty (60) days this license shall thereupon be terminated, provided 
however that such termination shall not release the Licensee from obligations 
already accrued hereunder and not performed, and provided further that if, 
during said Sixty (60) days' notice period, the default named in said notice shall 
have been made good then this license to continue as if no default and notice had 
been made or given. 
17. At the expiration of any one year from November 1, 1929, Licensee 
may terminate this agreement upon Sixty (60) days' notice in writing to Licensor 
of its desire and determination so to do, provided however, that such termination 
shall not release the Licensee from obligations already accrued hereunder and 
not performed. 
18. In case of differences of opinion regarding any of the terms of this 
agreement, the dispute shall be submitted to arbitration. Each party shall 
select one arbitrator and if they, after five days, fail to agree upon a third, the 
United States Court for the Detroit District shall be asked to appoint such a 
third arbitrator, and the decision of a majority of the arbitrators shall be binding 
upon both parties. 
45 
In witness whereof, we have hereto set our hands and seals at Detroit, 
Michigan, on the day and year first above written. 
Witnesses?(Signatures) : 
L. A. Wright 
Adolf Widmann 
(Seal) 
Attest: Milton Tibbetts 
Assistant Secretary 
Hermann Dorner 
PACKARD MOTOR CAR COMPANY 
Alvan Macauley 
President 
2. Packard to Begin Building Diesel Plane Engines Soon 
Will Start Construction at Once on New  Three 
Story Factory to Handle Work 
[From Aviation, March 2, 1929, vol. 26, no. 10] 
DETROIT, MICH.?Indications that the Diesel type airplane engine, re- 
cently developed by Capt. L. M. Woolson, chief aeronautical engineer of the 
Packard Motor Car Co., will become a commercial reality and possibly a revolu- 
tionary factor in airplane engine design, is seen here in the announcement of the 
concern that it will begin construction immediately of a $650,000 plant to produce 
the engines in large quantity for the commercial market. 
The new plant, according to the an- 
nouncement by Hugh J. Ferry, treasurer of 
the Packard firm, will be completed and in 
operation within five weeks. Between 600 
and 700 men will be employed and, ac- 
cording to expectations, production will be 
carried on at the rate of about 500 Diesel 
engines per month by July. 
The Packard Diesel was announced first 
in October, following experiments covering 
several years. The original engine was 
placed in a Stinson-Detroiter, which was 
flown successfully by Captain Woolson and 
Walter Lees,  Packard pilot.   Since that 
time Captain Woolson has built four of 
the engines, all of 200 hp. capacity, de- 
veloping 1 hp. for every 2 lb. of weight. 
The Diesel, installed on the Stinson- 
Detroiter, it was said, now has had 200 hr. 
flying time, and gives not the slightest in- 
dication that it will need an overhauling 
for some time. The other three engines 
have been tested on the block in the com- 
pany's research plant. 
It is claimed by the builders that the 
Packard Diesel will produce a saving of 
about 20 per cent, in fuel consumption as 
compared with engines using gasoline.    It 
46 
is claimed further that the Diesel will 
prove far more reliable in construction 
than any airplane engine yet developed. 
Evidence of this, it was pointed out, is 
seen in the performance of the initial 
Diesel. 
DETAILS NOT ANNOUNCED 
Although neither Mr. Ferry, nor Cap- 
tain Woolson, would disclose any technical 
details as to the engine's construction in 
making it applicable to airplane use, the 
secret of its success was reported to be an 
especially designed pumping device creat- 
ing high compression necessary for Diesel 
firing. 
Since announcement of the engine, the 
Packard factory has been literally a Mecca 
for engineers from many parts of the 
world wishing to see the engine. The 
Crown Prince of Spain, in Detroit last fall, 
was given a flight in the Diesel powered 
Stinson. None of the construction secrets, 
however, have been divulged, it was said. 
The Packard announcement set at rest 
rumors that the company planned construc- 
tion of a plant costing several million dol- 
lars, as well as reports that the company 
was going into the production of airplanes. 
"Our efforts," Mr. Ferry said, "will be 
confined to the engine, or power plant end 
of the aircraft industry. We will con- 
tinue to build the water-cooled type we 
have been producing for years." The new 
Diesel plant will be primarily an assembly 
plant, although some machine work will be 
done there. The bulk of the machine work, 
however, will be done in the present Pack- 
ard machine shops. 
Although no approximation of selling 
price on the new Diesel was divulged, it 
was intimated that the engine will retail at 
a price competitive with or slightly under 
the price of present gasoline consuming 
air-cooled engines of that horsepower 
range. Captain Woolson will have com- 
plete charge of the Diesel plant, it was an- 
nounced. 
3.  Effect of Oxygen Boosting on Power and Weight 
[From P. H. SCHWEITZER and E. R. KLINGE, "Oxygen-Boosting of Diesel 
Engines for Take-Off," The Pennsylvania State College Bulletin (April 1, 1941), 
vol. 35, no. 14, p. 25.] 
Practical Conclusions 
Airplanes require about one third more power during the take-off than 
in flight. In diesel-engined airplanes the size of the engine could be 
reduced by 25 percent by feeding oxygen into the intake air during the take- 
off. Applying the results of the experiments to a transport plane, Fig. 31 
shows the possible weight saving with various oxygen boosts. The curves 
are based on 6000 cruising horsepower and an estimated engine weight of 
2 lb per hp. 
For the take-off 8000 hp are necessary. To supply the additional 2000 
hp, 200 lb of oxygen are fed into the intake air during the take-off.   The 
47 
Figure 38.?Effect of Oxygen Boost on Power and 
Weight. (Cruising horsepower 6000, takeoff 
horsepower 8000.) 
O IOO 200 300 
OXYGEN USED FOR TWO MINUTES TAKE-OFF, LB 
volume of 200 lb of liquid oxygen is approximately 20 gal. Standard liquid 
air containers of 55 litre capacity weigh 75 lb. Therefore the weight of the 
oxygen and container is 350 lb while the possible saving in engine weight is 
4000 lb. The weight per take-off horsepower is thereby reduced from 2 
to 1.54 lb.   The calculation is shown in Table 1. 
Oxygen addition may be used for starting diesel engines. The raising 
of the oxygen concentration from the normal 21 per cent to 45 per cent was 
found to be equivalent to a raise of approximately 10 cetane numbers as 
far as starting is concerned. 
Five per cent increase in oxygen concentration eliminated exhaust 
smoke completely. 
TABLE 1 
Normal horsepower    6000 
Take-off horsepower    8000 
Normal fuel consumption   0.4 lb per hp-hr, or 
53.5 lb per min 
Normal air consumption    900 lb per min 
Normal oxygen consumption, 21 per cent oxygen      189 lb per min 
concentration 
Boosted oxygen consumption, 32 per cent oxygen      289 lb per min 
concentration 
Oxygen to be supplied    100 lb per min 
Weight of 8000-hp engine    16,000 lb 
Weight of boosted 6000-hp engine   12,000 lb 
Weight of oxygen for 2-min boost    200 lb 
Weight of container for 29 lb of liquid oxygen . .   150 lb 
Net weight saving by oxygen boost    3650 lb 
Weight per horsepower, nonboosted engine   2 lb 
Weight per horsepower, boosted engine    1.54 lb 
48 
U.S. GOVERNMENT PRINTING OFFICE : 1965    O?733-577