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Unformatted text preview: d isplaced by the "high-tension" system with spark plugs which was used
i n all other successful airplane engines, and, in its essentials, is accepted
p ractice to date for all spark-ignition engines.
80 C eramic-insulated spark plugs were generally used in the United States
before 1921. Both mica and ceramic plugs were used in Europe. From
a bout 1921 t o 1940 m'ca plugs were generally used. The development
of new ceramic materials about 1940 caused a universal change to this
C ARBURETION. A t the time of the Wright brothers' first flight, little was
k nown about carburetion, and various devices were used to introduce
fuel to air. As mentioned earlier (p. 13), the Wright brothers used gravity fuel feed from a small can to a heated surface in the inlet pipe. Manly
used a large sheet-metal box filled with porous wooden blocks, a scheme
o riginally conceived by Balzer. These blocks were saturated with fuel,
a nd the engine air was drawn past them, in the hope that a combustible
m ixture would result. The Antoinette engine and all of the Wright
b rothers' engines produced during 1907-1912 used a small pump to inject
fuel into the inlet ports. The carburetion system used for the Gnome
r otary engine has already been described (p. 25). All these systems
r equired experimental adjustment, good for only one engine speed.
M eanwhile, float-type carburetors were being developed for automobile use, and these were used by most aircraft engines after the Gnome
a nd Antoinette. Float-type carburetors were used by the Wright brothers
on their later engines, and were generally used for aircraft engines up to
a bout 1935. A floatless carburetor was introduced by the ChandlerGroves Corporation in 1935, and the Stromberg floatless injection-type
c arburetor became operational about 1938. Since that time most military and transport engines have used floatless-type carburetors, many of
t he injection type. Light-plane engines have, generally, continued to use
float-type carburetors, although injection systems are available for this
D irect injection into the individual cylinders was used
in gasoline engines for a short time on some Pratt & Whitney Wasps in
1 931-1932. T his method was developed to service use in World War II in
G erman military engines. It was adopted by Wright Aeronautical Corporation for their R-3350 engine in 1944.
I njection through nozzles located at each inlet port, first used on the
A ntoinette engine of 1906, h as been used to a limited extent in light-aircraft
engines since about 1946.
S TARTING. H and starting by the propeller was standard before 1920.
S ubsequent development included simple hand cranks, hand cranks with
i nertia flywheel, cartridge starters, air starters, and finally the present
electric starter with storage battery.
F UEL INJECTION. 81 B EARINGS AND LUBRICATION. M ost radial engines, even as early as the
G nome (fig. 20), used ball or roller bearings for the crankshaft. This practice has been continued with few exceptions, of which...
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- Winter '14
- The Land