fits together.” His words could apply to
any builder.
Jack obtained copies of the original
Royal Aircraft Factory drawings, and Jim
Kiger, a friend in California, provided him
with nine other drawing sheets, each 30
inches wide by 8 feet long. These drawings depicted every part of the airplane,
including dimensions and material callouts. “I love trying to see how our
forebears were so smart to do all this
without computers and CNC machines
and yet kept the precision they had. It
amazes me what they did,” Jack said.
The amount of work that Jack got done
in a small space could be equated to watching 10 circus clowns climb out of a VW Bug.
His work space and machine shop is a two-car garage (with a car in it), a yard building
that would commonly be used to store garden tools, and the backyard itself. “The
neighbors love it,” he said. “I’d sometimes
hear screeching brakes as people drove by.”
His project did not see an airport until he
was ready to mount all the wings and control surfaces for the first time.
Emilio de la Cuadra started an automo- bile company in Spain at the start of the 20th century and hired a Swiss engi- neer named Marc Birkigt to work on the designs of gasoline engines. In 1902, the ownership changed hands, but Birkigt stayed on as the key engineer, and the Fábrica Hispano-Suiza de Automóviles (Spanish-Swiss Car Factory) was born. after the engine starts, the pilot switches to the engine-driven pump. to - r t e i s , t es THE HISSO
Over the next several years the product
line grew to include aircraft engines, and
factories were established in other countries. The first factory in Paris, France,
was known as Hispano France, but
when a larger factory was later built, the
name was changed to Hispano-Suiza.
To the aviation users of the French-built Hispano-Suiza, the engine simply
became known as the “Hisso.”
With the start of World War I, Birkigt
sought to design a better aircraft engine.
Most rotary engines used by all combatants in WWI had a service life of less than
20 hours, and his Hispano-Suiza was a
giant leap forward in technology.
As production requirements for the Hisso
started to exceed the French production capabilities, several companies were
licensed to produce them, including the
Wright-Martin Company in the United
States (the company that produced
Jack’s engine). Some of these “
out-sourced” engines were inferior to the
originals because of quality control problems, but others claimed improvements.
The Wright-Martin Company said that,
with its model E- 2 variant of the Hisso,
“Improvements made by the Wright
engineers have produced an aircraft
engine that will operate for longer periods at higher mean effective pressures
than any other type of internal combustion engine. Several types weighing less
than 20-1/2 pounds per horsepower have
run for periods from 200 to 300 hours
with but little attention.”
WOOD AND METAL
“Except for a few complicated parts,
building the S.E.5a is simple if you just
build one part at a time,” Jack said. “It
doesn’t get complicated until you put
them all together.” Despite being a wood
plane, the number of metal fittings and
castings used in the construction is staggering. The hundreds of carefully crafted
wood parts are connected with metal fittings at each end of the part. There are
numerous off-the-shelf parts and fittings
made of modern materials that could have
been substituted for the real thing and
would never have been seen on the finished plane—but Jack wanted a real
S.E.5a. Besides aluminum and a few brass
parts, most of the metal parts’ specifications were identified as mild steel (Jack
It is a V- 8 like its contemporary, the
90-hp Curtiss OX- 5, but beyond that,
there is little comparison. The Hisso
develops twice the horsepower of the
OX- 5 while weighing 60 pounds less. (The
first Hissos had 1 40 hp, but most used in
combat were rated at 180 to 200 hp.) The
design incorporates dual magnetos and
has self-oiling dual overhead camshafts
driven off the crankshaft through vertical
shafts with bevel gears. Valve lash is set
at an amazing 0.079-inch clearance! Fuel
flow is maintained by an engine-driven
air pump that pressurizes the fuel tank.
To start the engine, the pilot first pressurizes the tank with a hand pump, and
Starting the Hisso
The starting system of the S.E.5a is
unique. The engine has dual mags and
two sets of spark plugs just like a mod-
ern engine. The magnetos are timed
at about 25 degrees before top-dead-
center and have a “come-in” speed of
about 600 rpm, meaning you can’t hand
prop the engine on these mags. So, a
third, hand-cranked, starting magneto
is provided and is timed to fire after
top-dead-center. The starting mag-
neto is located on the right side of the
fuselage just below the cockpit coam-
ing. Priming the engine is accomplished
by squirting fuel into four priming cups
located in the top of the engine. Initial
starting fuel pressure is supplied by a
cockpit-located manual pump.
