The fatigue
flight test program was going well
and we were accumulating a wealth of
in-flight data from the strain
gauges which were stuck like leaches
over airframe and rotor systems.
Youtube has a video of
a demo run which is slightly boring
for the uninitiated but shows all
the strain gauges and computer
gear..
The flight test program was quite
specific and disciplined as not only
were we hopefully validating the kit
manufacture's data but also plotting
stability and assessing myriad of
other requirements for certification
requirements in Australia.
Notes from
FAQ - youtube video
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All
flights were done at gross
weight |
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The
VHS video camera for simplicity
was mounted upside down to the
RH cabin roof. Its purpose was
to record instrument parameters
and flight control positions
"just in case".
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My
microphone also recorded
directly to the camera as I
talked through every action/task
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The
yellow plastic paintbrush was
taped to the cyclic stick so
that all cyclic movements were
visually recorded |
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Two
tapes on the left leg of my
flight suit indicated full fore
and aft travel for an unusually
accurate visual measurement of
cyclic stick displacement when
plotting cyclic travel V
airspeed |
|
The
386 computer was "big time" in
those days and the additional
16mb of ram required to run the
Amlab software cost over $1000 -
equivalent to 2009$3000.00! The
computer and monitor were both
240 volt and connected to an
inverter. On one trip, I
couldn't avoid a very fine misty
sun shower and had visions of
being the first pilot to be
electrocuted by household mains
power in flight when the monitor
copped some moisture in the back
vents and blew up. |
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The
Squiggly lines on the monitor
are the various strain gauge
channels feeding into the
computer. You can see for effect
the resultant when I simply
wiggle a blade on the ground.
Which goes to show that rotor
blades prefer their designed
operating RPM to reduce slow
speed root bending moments
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The
rotor blade strain gauges feed
back down thru a slip ring as
indicated by the aeronautical
engineer |
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There
were strain gauges inside the
tail boom where it joined the
main frame |
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The
black marks on the LH rear of
the tail boom where the tail
rotor slip rings were mounted,
were caused by an electrical
fire in flight - which was
interesting experience at the
time
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My flight
note assessments
from the time showed that this
particular machine had/was:
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Unstable at
higher speeds (I noted it down
as flat plane effect)
|
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Underpowered at gross weight or
DA + 2000 Ft AMSL
|
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Limited
useful load |
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More
susceptible toward negative G
than the R22 |
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Extremely
smooth and quiet engine probably
contributing to less airframe
and pilot fatigue
|
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Limited
range and endurance in
comparison to an R22
|
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Met
(exceeded) manufacture's
published VNE with forward
cyclic stick displacement for
approx 15 Kts gust (118 Kts
exceeded) |
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Positive
progressive cyclic stick
displacement |
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Poor tail
rotor control in tail wind
conditions exceeding 10 kts
|
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Smooth
rotor system |
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Good
hovering stability (probably due
pre-cone and stiff main rotor
blades) |
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Rigid
undercarriage - limited vertical
decent G absorption
|
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The
possibility of not reaching full
pedal in an emergency situation
as the heel of a shoe could get
caught on a lip in the floor
close to the pedals (this
happened to me and was another
interesting unforgettable
moment) |
What
would you do if the cyclic jammed in
flight? or - if the cyclic control
cables were connected in reverse
See part
two for what we did when the swash
plate uniball jammed in flight - in
a turn close to the ground and the
other incident with the crossed
cyclic controls
TC
