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A
free teetering two blade rotor system doesn't tilt due to precession.
Gyroplane rotor blade control is rotor head induced and aerodynamic.*2
The flying of a gyroplane is not "weight shifting". |
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A
free teetering, two blade, rotor system on a gyroplane doesn't tilt
for a direction change from a force on the rotor disc applied by
the pilot. (Rotor disc only exists when the two blades are
spinning)
"A gyroplane pilot only has control of the rotor head. The
rotor head is in balance with the hub bar during sustained flight
(fixed turn or level flight).
"To change the level of the rotor disc (to initiate a turn)
the pilot puts the rotor head out of balance with the hub bar.
This causes a difference in pressure on those areas of the rotation
disc, which causes a change in level of the disc, applied about
90 degrees later.
"The overhead rotor disc changes it's level to balance again
with the rotor head.
Because there is a momentary delay from pilot input to final movement
(response), the pilot must learn to wait after making a control
stick adjustment, then make another adjustment if necessary to complete
the turn. This "wait" reflex on the part of the pilot
is particularly important in learning to fly a gyroplane."
Precession response is triggered due to an
aerodynamic force being applied by "vaning" of a rotor
blade 90 degrees earlier on the rotor disc.
There is no way a stick input could directly force the rotor disc
to change levels.  That's
why older style rotor heads used an overhead stick down from the
rotor head to change the rotor disc plane to a different angle.
They did have to use brute force. Sometimes in recovering from a
steep descent the pilot would apply too much direct change and the
rotor plane would be aerodynamically "caught" in forward
motion (drag), to over come the pilots strength.*1
With proper set-up you can fly a gyroplane hands free. The rotorhead
and rotor hub bar always seek to remain in balance. The gyroplane
is hanging from the rotor head and subject to "g" forces
and aerodynamics as the rotor blade disc (plane) is flying through
the air. |
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Gyroplane
Hub Bar,
Spindles and
Gimbals
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Bensen type |
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What is gyroscopic precession?
On any spinning wheel (disc / plane) there is a delayed reaction
to change in levels. Even though a two blade rotor system is not
a wheel, it becomes similar to one when spinning at a high enough
rate. This creates gyroscopic effect and it behaves in like manner.
(see diagram)
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Commentary: For some unknown
reason, gyroplane designs have been moving away from "tried and
true" to become more like aeroplanes.
What would "tried and true be"? Basically, the over head
stick. The over head stick arrangement allowed easier input adjustments
to the rotorhead, by a ratio of 13:1.
The tail area is also becoming larger as open frame moves to enclosed
cabin. Unfortunately the tail design is ignoring "tried and true"
and not considering the Cone
Stabilzer. |
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The original Bensen style
rotor head was not a offset gimbal type rotor head, rather it was
a spindle head design taken right from Haffer's Rotachute glider.
Although not really well designed for gyroplane use, it has not
been on record as failing in use.*1
It's too bad more design work had not been made in the area of bearing
support which is the spindle heads weak point.
However, the Offset Gimbal Head design is much better. It is self
stabilizing in pitch. The Offset Gimbal Head almost balances the
amount of lift created to the amount of drag that is being simultaneously
produced.*1 A spring system is used
to complete the balance. |
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