fore 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 w