How to use the G-23 magnets with the Futaba GV-1 Governor

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2 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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How to use the G
-
23 magnets with the Futaba GV
-
1 Governor


Rich Bono, 7 Redfield Circle, Derry, NH 03038

© Copyright 2003

(Version 1.
1

6
/2
6
/2003)



The Futaba GV
-
1

(
http://www.futaba
-
rc.com/radioaccys/futm1001.html
)

governor controls the
engine speed in he
licopters by having you install a magnet in the fan of the engine. This is a
delicate procedure to perform. You must drill a hole in the fan, epoxy the magnet into the whole
with the proper polarity. After doing this you must balance the fan to be sure tha
t you do not
induce too much vibration into your helicopter.


With the added magnet, there is the risk that a magnet will come loose during operation. This will
cause the governor to fail to control the engine speed as well as present a physical danger to
people if the magnet strikes someone. Even the Futaba instructions warn you to check the
magnet after every 10 flights.


In the Gas X
-
Cell (or any
Zenoah G
-
23

a.k.a. G230PUH

powered helicopter) you can use the
magnets in the engine flywheel as a trigger so
urce for the Futaba GV
-
1 instead of mounting the
magnets supplied by Futaba.


Some may ask why I didn’t simply mount the magnets in the fan as per the Futaba GV
-
1
instructions. The reasons are:




There is barely any free room to mount the sensor and its br
acket under the fan

in the
Gas X
-
Cell
. The G
-
23 takes up a lot of room in this X
-
cell!




There wi
ll be no added vibration issues to worry about!





There will be no n
eed to try to balance anything as all moving parts in the helicopters are
un
-
touched.




Ther
e is NO chance that a
magnet will fall off in flight to cause a failure of the governor to
control the engine/head speed!




There is NO chance that a magnet falling off while the engine is operating will injure
someone

or jam the gears of the head/tail mech
anism
!




This is easier to do than installing the magnet and aligning the sensor.


Note, there does appear to be three magnets in the G
-
23 flywheel, but only one of them seems to
be the proper polarity to trigger the GV
-
1 sensor. How convenient!


In testin
g I found I could get a 90% sensor reading right through the aluminum case of the G
-
23
using this pickup location. Placing the sensor at this location keeps it as far away from the
magneto pickup coil and ignition system (ignition coil, sparkplug, magneto
pickup coil) as possible
to minimize any radio interference issues.

Futaba says that as long as you get a 60% or higher
sensor reading, then the governor will operate properly.


The yellow spot in this picture

of the G
-
23
shows the approximate location

on

the front of the
helicopter

where the GV
-
1 p
ickup sensor will be positioned.

As mentioned, this places the sensor
as far away as possible from the ignition system of the G
-
23.



You will need to build a bracket and a standoff block to mount the GV
-
1 sens
or in the position
shown by the yellow spot.


First, build a bracket for the GV
-
1 sensor. You can use a Miniature Aircraft part number 106
-
66 to
do this, or build it f
rom either some aluminum or 3/16 or ¼ inch thick

aircraft plywood.


Do not use anything t
oo flexible as you don't want it to flex or vibrate

during operation
. If you use
plywood, paint it black to protect it a
nd make it look better. Whichever you use, you need
two of
them. One will mount between the front landing gear bolts and the other betwe
en the rear landing
gear bolts so that the frame of the X
-
Cell will not be tilted to the rear when on its skids.

If you
choose to use the ¼ inch think aircraft plywood, you can omit the stand
-
offs (3923
-
1) between the
frame and the landing gear.


The brack
et will be mounted between the landing gear and the bottom for the frame rails (105
-
86). The landing gear stand
-
offs (3923
-
1
)

will be between the bracket and the landing gear
(3923), not between the bracket and the frame rails (105
-
86).


Use the
bracket (1
06
-
66)

as a mounting point for the GV
-
1 sensor. You will need to drill two 2mm
holes in th
e bracket

at the appropriate point.
To determine the proper place to mount the GV
-
1
sensor, remove your landing gear from the X
-
Cell. Then place the bracket in positi
on and slide
some bolts through it and the frame rails (105
-
86). Place the sensor on top of a 6mm thick
standoff block. Position the sensor so that it will be in the position as shown in the pictures. Mark
this spot so that you can drill the two 2mm holes
for the mounting hardware.

Use the GV
-
1 sensor
as a guide to drilling the two 2mm holes.
Elongate the holes to allow for some adjustment of the
GV
-
1 sensor.


The bracket is

part "A" as identified in the included picture. Note that my mounting bracket was
made from some scrap frame
material;

the 106
-
66 part will not look anything like this!




The standoff block
(“B” in this photo)
was made from some

6mm thick
piece

of plastic cut from an
old anti
-
rotation arm (Miniature Aircraft part number 0247). This is

part "B" as identified in the
included picture.

You can use some 6mm thick aircraft plywood and paint it black (do not use
‘light
-
ply’). You need to raise the sensor 6mm off the surface of the bracket so that it will be in the
correct position on the G
-
23

case as seen in the first picture.

Use the GV
-
1 sensor as a guide to
drilling two 2mm holes in the standoff block.


When you mount it, you do not want the sensor to come in contact with the G
-
23!! You do want a
very small gap between the sensor and the en
gine case so that any engine vibration is not
transmitted directly to the pickup sensor.


Note that in this picture, "A" is pointing to the mounting bracket, and "B" is pointing to the offset
block. For your information, the offset block "B" is about 6mm

thick made from a piece cut from
a

salvaged anti
-
rotation arm (Miniature Aircraft part number 0247). The mounting plate is 2mm thick
Miniature Aircraft part
number

106
-
66.


I used two of these brackets, one under the front landing gear mounts as shown a
nd another
between the rear landing gear mounts so that the helicopter would still sit level.

Here is a view showing how the bracket is mounted between the frame rails and the landing gear
stand
-
offs (3923
-
1). Plus is shows a clearer view of the standoff
to raise the sensor into the
correct position on the G
-
23.



Here is a full view of how the sensor, bracket and offset block are mounted.