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The first task is to
assemble the transmission. Each of the ring gears, pinions, and spider gears are
placed into the transmission case with tight tolerances. Typically this is done
by the manufacturer and would not be required by the purchaser of a GEN H-4. The
transmission comes completely pre-assembled.
Jon, adding lock
tite to the pins holding the spider gears in place.
This picture shows the final assembly step of the transmission. The nut holding
in the main rotor shafts to the transmission is being tightened. This is
the naked fully assembled transmission before being placed on the air frame.
Note the clutch rings on each of the four sides of the transmission. These rings
are where the transmission receives it's power from the four engines through
centrifugal clutches.
Next is to assemble the
engines including placing the pistons on the rods, placing the cylinders over
the pistons, and placing the carburetors on the air intake ports of the
cylinders. In this picture Jon is connecting the electronic ignition to a
connector that will connect with the wiring harness.
An engine test is in order
before placing the engine on the air craft. Each engine is tested for maximum
power output, response time in changing RPM, endurance, and thermals. This
picture shows Jon & Richard placing a standard carburetor on the engine for the
test. All engines are tested with the same carburetor to assure consistency of
variables.
For the engine test a large non-aero dynamic
prop is place directly on the drive shaft to provide drag and simulate a heavy
load. The test is timed while the above mentioned variables are measured and
compared with expected results.
The frame of the air craft is constructed of a light weight 3mm thick aluminum
pipe. Attached to the frame as shown in this picture is a fiberglass cowling that
will hold the fuel tank, batteries, and electronic components. Also shown is the
safety harness attached to the frame using aluminum tubing.
Another view of the frame of
the GEN H-4 in final assembly before placing the power unit on the frame.
The multi-directional rail guided gimbal,
handle bar stem, and transmission are placed on the aluminum frame.
Each engine is attached to the transmission
one at a time. The centrifugal clutch does not require any special attachment to
the transmission because it does not engage until the engine is rotating above
3,000 RPM. Each engine assembly is independent with each having its own starter,
carburetors, & electronic ignition.
Once the engines are in place
the exhaust pipes are attached to the underside of each of the engines. The
do-nut shaped exhaust manifold can then be mounted to the exhaust outtakes using
springs to hold it in place.
The instrument panel is made of fiberglass
along with the other cowlings on the air craft. The throttle control is mounted
in position and all wires are carefully placed behind the cowling for neatness
and order.
With a little elbow grease
the hand grips are placed on the handlebar just like a bicycle.
These are the CDI ignition wires running from
the "backpack" of the air craft up to the engines or "power unit." These
wires can be separated if desired so that the power unit can be removed from the
frame during transport and/or servicing without having to unwire the entire
wiring harness.
Here, Jon is attaching the throttle cables to each of the carburetors on the
engines. The main throttle cable is set up to drive all four engines
simultaneously. This results in each of the engines engines engaging the
transmission at the same time and keeping them all synchronized.
A 2.5 gallon fuel tank sits in the backpack
of the GEN H-4. There is an electric fuel pump in the bottom of the tank that
aids in getting fuel to the power unit. Any unused fuel returns to the tank
after cycling the system.
These are the molds used for making the carbon fiber rotors on the GEN H-4.
In the picture above the top half of the
mold is being lifted off to reveal the finished rotor. The carbon fiber rotor
is heated and compressed in the mold to create the finished product. It is later
painted white to reflect heat.
After the rotors have gone through thrust
testing and balancing they are place on the air craft. The rotors tie into a hub
that snugly fits over the drive shafts of the transmission. They are carefully
tightened down and then are ready for use.
A final assembly check by someone other than
the assembler is wise to check for errors.
Here, Jon is connecting the wiring harness to
the NiCad power source inside the backpack while Nakamura-san checks Jon's work
above the air craft.
This is the GEN H-4 team after an exciting
day at work assembling several air craft for testing. From left to right: Jon
Plummer, Tami Sakamaki, Yasutoshi Yokoyama, Richard Plummer, Nakamura-san,
Aizawa-san
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