|
|
|
|
|
|
|
|
|
Align HH Gyro Setup (Telebee/Zoom) |
|
|
|
|
|
The Align gyro is basically the Telebee gyro badged under the Align brand.
It is a dual rate gyro in that it supports ordinary gyro stabilisation
as well as heading hold mode.
The gyro has two methods of setting the gain, either through an adjustment
pot on the gyro itself or via remote gain through plugging the gyro into
your transmitters appropriate channel for adjusting gain remotely on a
gyro.
If you don't have a specific function for adjusting gyro gain then any
spare channel will do providing the ATV or end points can be adjusted on
that channel (to set the gain).
The gyro also has two other features on it's casing, on is an LED indicating
that the gyro has finished it's initialization and is now operational and
lastly there is a slider switch for reversing the gyro to ensure it is
giving the correct inputs, depending on how you have mounted it.
Before going any further the following things should be checked otherwise
the gyro may not behave or work correctly or excessive tail wag my be present.
- Blades and the head of the helicopter should ideally be balanced to eliminate any unnecessary vibration affecting the gyro.
- The tail pitch slider should be able to move freely and easily with no
obstructions or notchiness.
- The carbon rod connected to the tail pitch slider control horn should be
able to move freely and should be directly in line with the control horn.
i.e. there should be no bends or flexing of the rod between the tail servo
and the tail control horn.
- The tail pitch slider ball links should be able to rotate freely. This means the screws holding the ball links in place need to be a little loose and not tightened down hard.
- The full movement of the servo should not cause any binding at either end
of the tail pitch slider travel. Make sure the appropriate hole has been
selected on the servo horn. Do not try to adjust the servo movement using
ATVs or end points, these should be left at 100%. On this gyro the ATV/end
points just affect the pirouette speed and don't affect the length of travel
of the servo.
- The gyro should be mounted the correct way up, the instructions for this
are in fact incorrect and if followed WILL cause a crash. The gyro should
not be mounted such that it's label faces towards the sky, it should be
on it's side with the label facing to either the left/right/front/rear.
In my picture below the label is facing the front of the machine. In this
orientation the gyro reversing switch (for me) is in the 'B' position but
this may vary by transmitter.
- The servo for the tail should be operating in the correct direction, more
on this below.
- The tail belt should be fairly loose such that it is almost possible to
make the belt touch itself when pinched together
- The tail rotor hub grub screw should be checked for tightness and that
it was fitted with locktite. It should be possible to manually turn the
tail and cause the belt to slip a notch. The hub itself should definitely
not rotate independent of the belt notching round, if it does the grub
screw is not tight enough and you could suffer an airborne tail failure.
- Revolution mixing on your transmitter (tx) should be disabled
- Any other tail mixing on your transmitter should be disabled
To check your servo is operating in the correct sense, when you command
left stick the tail servo control horn should move towards the front of
the helicopter.
For the benefit of beginners I should point out that when you command left
stick it is the nose of the helicopter that turns to the left NOT the tail
moving to the left.
Below are some pictures of the setup to help with the above description
: |
|
|
|
|
|
|
|
|
|
|
|
OK, so now we have to check the gyro is not reversed. Take the main blades
off (for safety) and/or disconnect the motor. You may also want to put
the motor on throttle hold (make sure before you do this that your throttle
hold is set at zero throttle) just in case you knock the tx whilst performing
the test.
Make sure the gyro gain is set high, 90% or so and is not in heading hold
mode, again this will vary by transmitter.
You can tell when you are not in heading hold mode as the servo will stay
centered, in heading hold mode the servo will creep to one extreme of it's
movement.
Now with the machine on a flat surface make sure you can see the tail servo
and in a short sharp movement turn the nose of the helicopter left. If
the gyro is setup correctly the servo should make a corrective movement
towards the tail of the helicopter, if it moves towards the nose then the
gyro needs to be reversed, move the slider switch on the gyro case from
it's current position to the opposite position e.g. A to B
If the servo doesn't move at all it is one of two things, either the rate
is too low and you couldn't see the corrective movement as it was too small
or your gyro is mounted with the label facing the sky and therefore didn't
sense the movement you just made at all. Whichever it is correct and try
again.
Once you have verified the gyro is not reversed it's time for a flight
test.
In a previous step you worked out what gain settings to use to get normal
or heading hold mode. Put the remote gain of your transmitter to around
50% sensitivity in heading hold mode. As an example on my transmitter (Hitec
Eclipse 7) this is a gyro setting of 75% (0-50% is non heading hold and
50-100% is heading hold mode).
Slowly increase throttle to get the X400 light on it's skids and then add
a little throttle to get it to just clear the ground. If the X400 suddenly
spins and you can't stop it then your gyro is reversed and you didn't correctly
set it up in a previous step. Just move the switch on the gyro case to
it's opposite position e.g. B to A.
If the X400 doesn't spin or you had that but have put it right you should
now be just hovering off the ground and you will either have some tail
wag or you won't. You may also find you are having to hold in a certain
amount of control to the tail (either left or right) to keep the tail in
one place. Land and use the tail trim on your transmitter to get rid of
the need to hold in tail input to keep it straight ie. if you were holding
left stick to keep it straight then add left trim to alleviate this problem.
Continue trimming until the model holds a relatively stable tail without
any stick inputs from you.
Now we can adjust the gain.
If you have tail wag then reduce the gyro sensitivity a few points at a
time until it stops. If you don't have tail wag then increase the gain
until you notice the beginnings of wag then back it off a couple of points.
We now have a stable hover, you may still get wag in forward flight, if
so just reduce the gain again by a few points at a time until the wag disappears.
Once you are happy that it is setup OK it's time to try non heading hold mode. Switch to this mode or adjust your gain appropriately to make the switch. Follow the same procedure above but instead of using the radio to adjust the trim of the tail adjust the tail pushrod length instead. If you need left trim then the tail pushrod needs to be lengthened, if you need right trim it needs to be shortened. Keep test flying and either lengthening or shortening the tail servo pushrod until you get to a position where you are very close to zero or only a couple of points of tail trim. Having reached this point you may find that you can now increase the gain without getting any tail wag, this is due to your mechanical set up being much better and the gyro not having to compensate for that. In non heading hold mode you should be able to get close to 100% gain, if you can't you may have a vibration throwing off the gyro. Check the head, main blades, feathering spindle, main shaft and so on to try to find the cause of the vibration.
Following this setup procedure switch back to heading hold mode and make
any trim adjustments that may be necessary (as before) on your transmitter
trims due to the tail pushrod length being changed. Again you may find
that you can achieve a higher gain setting now that the mechanical setup
is correct.
The golden rule with this gyro is that in non heading hold you make mechanical
adjustments (pushrod length) in heading hold mode it is done using the
transmitter trims.
If you are unable to eliminate wag then you either have an excessive vibration
upsetting the gyro OR something is too tight or binding in your tail pitch
movement mechanism. Disconnect the servo and feel for any binding my moving
the rod manually. Double check that the ball links on the tail pitch slider
can rotate freely and were connecting to the tail blade holders with the
'A' in the correct orientation as per the X400 manual. Revisit my list
of things to check at the top of this page to make sure nothing has been
overlooked. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|