Putting a Gyro onto an Airplane: I
have had experiances with putting a Gyro onto an airplane and want to
pass the information along. First off, I'm an experianced Fixed wing as welll as Helicopter
pilot and first put a gyro onto the ailerons of a high wing trainer
back in 1993. It was a Futaba mechanical Rate gyro and my intentions
were to dampen the effect in the wind. At the time, Some Large Scale
pilots were doing the same thing on the ailerons and elevators to
smoothen out the response of their planes. Putting Gyros to dampen the
unwanted movement of an airplane is nothing new but does require some
knowlege of how to set it up and how gyros operate.
Modern Solid State
RC gyros are primarily used in controlling the tail of a helicopter
which without the gyro would be quite troublesome. Although they
sell gyros specifically marketed to airplane users, I wish to focus on
gyros marketed to helicopter pilots since they are less expensive and
easier to come by.
What is a GYRO? Modern
solid state gyros have a sensor(s) in them that sense rotation. They
are place in line (in series) between your Rx and the servo you want to
correct. Traditionally in helicopters, you plug the gyro into
your Rx ch4 (rudder/tail) then the rudder/tail servo plugs into the
gyro. When a gyro senses the movement of the axis, it modifies the
servo signal comming from the Rx to add corrective action. It can
also sense when you move your sticks to know when you are WANTING to
move that servo so it knows to move the servo and not correct. During a
'wanted' movement, it can sense the rotation rate and correct if the
rotation rate is faster than desired.
Why use a Gyro? There
are several reasons to use a gyro on a plane. The main reason is to
make the plane more stable to fly in the wind. Wind can do
several things. On an Aileron axis, it can flip the wing over during
wind gusts or wind velocity changes. This is very noticable when you
approach close to objects such as trees or the ground where contour
changes. Even the ground. You don't need to even be that close to
have the wind change. It can be daunting to land a plane in high
winds because a cust can flip the wing over just as it's velocity is
low enough for you not to have enough corrective throws to compensate
in time. A gyro will correct for the wind cust MUCH faster than
you can. On the elevator, it can compensate for a tail heavy
plane to make it more stable. You can install a gyro and fly a tail
heavy plane and it can be more aerobatic. Modern Jet fighters are
designed tail heavy with compensating gyros to allow the pilot to "fly
by wire". Gyros are also used on rudders and nose wheels to
compensate for ground handling or engine torque for takeoff.
There are LOTS of nay-sayers that say "if you need a gyro, then
don't fly". I say that's a bit closed minded. I think it's ok to
use what ever tools are at your disposal to make a plane more stable if
that is your desire. What is the difference between putting a
gyro in a small plane to make it more stable in the wind than to go out
and spend hundreds of $$ to get a .90 sized nitro plane or say 50cc gas
plane that is more stable in the wind? Bigger planes are more stable in
the wind, does that make a large plane pilot less of a pilot because he
is flying a bigger plane that can handle more wind? When they
came out with Heading Hold gyros,did the sponsored 3D pilots reject it
because it made it easier to do stunts? No, they accepted the
technology and used it. If putting a $30-$60 gyro on a small
plane allows you to fly it more often, then why not do it?
Types of Gyros you will find: Rate Only This
gyro will dampen unwanted movements. Movement in the axis of rotation
that was not induced by the pilot. The resistance is done by the gyro taking your
servo output from the RX and modifying the signal going to the servo to
give corrective movement.
Heading Hold (sometimes refered to as AVCS, Head Lock or Tail Lock) This
type of gyro will remember the amount of movement and work to bring the
rotation BACK to the original location. In this case, the gyro
maintains corrective movement in it's modified signal to the servo
until the rotation returns to it's original position. This is the
current popular type of gyro used by helicopter pilots. Most Heading
Hold Gyros allow you to set it up in either Rate mode or Heading Hold
mode. Most Heading Hold (HH) gyros have a spare servo input wire that
allows the Tx to set the gain of the gyro as well as if it is in Rate
or HH mode. When not using this spare input wire, most gyros have a
GAIN dial on the gyro that is used to set the gyro gain. For
simplicity, I will go into how to use the HH gyros using the gain
channel connected first.