Comments

Comments of Aeronautical Engineers: These comments appeared in

_Aviation_ for February 15, 1930, just a month before the Packard diesel

received its approved-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 commercial operation in the United States there seems to be

little or no improvement 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, Massachusetts

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."

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 evident, 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

flexibility 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 Company): "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

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 aircraft 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]

[Illustration: 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 underpowered. 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 conversation 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.

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

Company. 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 insisted 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 airplane

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 number 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 Trimotor 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 amphibians, 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 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.