138 MODEL AVIATION
TANKS SEEM TO leak at the worst
time—usually when you are at a contest.
For this reason, it is a good idea to have a
flight-tested tank standing by at all times.
But even with a spare tank, it is not
always easy to make the switch; it
depends on the method of installation. In
fact, the potential of a tank leak can
increase or decrease with the method of
installation.
For several seasons, I mounted my
tanks using a bolt through the middle of
each. I loved how easy it was to change a
leaking tank. This was good because tanks
using this method will eventually leak. I
remember one particular Nats during
which Gene Martine helped me repair a
leaking tank each evening. Night after
night, he would preach about the way he
mounted his tanks.
I switched from using a single bolt
through the middle to using clear silicone
CONTROL LINE AEROBATICS
Curt Contrata, 6783 Nightwind Cir., Orlando FL 32818; E-mail: [email protected]
and balsa strips to hold the tank in place.
I also used silicone to glue the tank vents
in place where they exited the fuselage.
This helped support the vents, and it
reduced their vibration and the chances
that the vents’ solder joints would fail.
Tanks mounted this way never seemed
to leak. There was no stress on the tank,
and it could not move. It was also a
lighter method than using a bolt.
The downside was that when a tank
did leak, or if you needed to make an
adjustment, the repair and swap were
more difficult. Another bummer was that
neither a tank adjustment nor a
replacement was practical at the field
because of the silicone’s drying time. I
have been forced to fly at a contest with
a leaking tank because of the time it
would have taken for the silicone to
cure. Gene preached again, and I finally
listened.
His method is simple and requires no
special tools or skills. No modifications
need to be made to the tank, so an offthe-
shelf replacement drops right in.
Tank-mounting methods that require
pieces to be soldered onto the tank not
only make it custom, but they are added
points of failure. Besides, if your tank is
stock, there are spares available
everywhere.
By using two small strips of
basswood and a few small drops of thick
cyanoacrylate glue to lock everything in
place, field height adjustment and tank
replacement are options, even between
rounds. Not being one who likes to
The part labeled ‘A’ is the clip and the part labeled ‘B’ is the bracket. You will need two
clips and four brackets for this tank-installation technique.
Once the tank is in position, the clips slide into place and get one
drop of thick cyanoacrylate glue at each end.
To avoid failure of solder joint where vents enter tank, make a
simple brace from a small piece of tin to support them.
08sig5.QXD 5/21/04 11:23 am Page 138
overcomplicate things, I endorse this
method for its simplicity and
functionality.
The bill of materials includes a few
inches of 1⁄8-inch basswood and 1⁄2-inchwide
double-stick foam tape. In the
diagram, the part labeled ‘A’ holds the
tank in position; I will call that the clip.
You will need two clips that are 1⁄16 inch
shorter than the width of the fuselage, or
21⁄8 inches for an SV-type fuselage. Part
‘B’ is glued permanently inside the
model; I will call that the bracket. You
will need four brackets, and the side with
the notch goes toward the tank.
To install the brackets, drop the tank
into the fuselage without tank shims. Lay
a scrap piece of 1⁄4 balsa on the top of the
tank; it is used as a spacer. The spacer’s
thickness will determine the maximum
amount of tank adjustment you will have,
less 1⁄16 inch. Position the two clips on top
of the spacer, approximately one-third of
the way from each end of the tank.
Before you glue the brackets in place,
make sure they are facing the proper
direction. Both sets of brackets should be
positioned to allow both clips to be slid
toward the center of the tank for
installation and removal. This is important
since you may be unable to remove the
clips if the brackets are facing the spinner
or the tail. When you glue in the brackets,
be careful so you don’t accidentally glue
in the clips, or you will have a problem.
Apply the foam double-stick tape to
the underside of the clips, on the side that
will face the tank. The tape is
approximately 1⁄16-inch thick, and with a
1⁄16-inch shim under my tank, I used three
layers of tape under the clip.
Do you remember the 1⁄4-inch spacer?
Being that the tape compresses slightly, it
adapts to small shim adjustments and
applies light pressure against the tank to
hold it in place.
Don’t remove the paper backing on the
last layer of tape—the one that will touch
the tank. The clip will need to slide into
position and should not be stuck to the
tank. Since the tank is slightly narrower
than the fuselage, you can use foam tape
on the sides of the tank to fill in the side
play. Leave the paper backing on the tape
where it will touch the fuselage.
Since the brackets take up space on the
sides of the tank compartment, you will
have to maneuver the tank into position.
Start by sliding the fuel pickup through
the firewall; keep the tank rotated slightly
as you set it down into the compartment.
Once it is in place, rotate it on the axis of
the fuel pickup. The additional space
allowed by the spacer helps the tank rotate
past the brackets and into position.
With the tank in position, slide one of
the clips under the bracket. It should be a
snug fit but should not crush the tank.
With trial and error, you will see how
August 2004 139
many layers of double-stick tape you will
need under the clips. Let the layers of tape
stick to each other, but leave the paper on
the last layer so the tape won’t stick to the
tank.
Slide the second clip into position.
Place one small drop of thick
cyanoacrylate glue on each end of each
clip to keep it in place.
When you need to remove the tank,
press down lightly on each end of each
clip. When you do, you will hear a snap as
the cyanoacrylate breaks loose, allowing
the clip to slide out. As a precaution, I put
one small dab of silicone where each clip
touches the tank, to keep the tank from
moving around during flight.
The most common place for our tanks
to leak is where the uniflow vent and
overflow tubing enter the tank. This joint
is easy to reinforce with a small piece of
tin measuring 1⁄4-inch wide and 3⁄4-inch
long that is bent into the shape of a “J.”
Laying the flat side against the tank and
the curved portion under the vents, solder
it in place, and the chances of having a
vent leak are greatly reduced.
Similar to the method of using the
silicone, this will add support to the solder
joint where the vents enter the tank. The
problem with using silicone is that when it
does eventually leak, it is difficult to clean
the area to solder. I hate to give him credit
again, but Gene showed me this too.
Bargains are nice, and it is even better
when it is a bargain for something for the
shop. Drawer and cabinet space in my
shop is at a premium. My shop tends to
be dusty, and I don’t like to have
everything out on open shelves. I have
found it easy to pick up odd pieces that
provide enclosed spaces to fill in above
and below my benches.
If you keep your ears and eyes open,
you will be amazed by how much furniture
is given or thrown away every day. Office
desks are nice because they typically have
better hinges and drawer slides, and they
have heavy tops that can sometimes be
repurposed when the desk is disassembled.
You can really score when someone is
remodeling a kitchen; then all your
cabinets will match.
Bedroom furniture is nice; however, I
tend to stay away from dressers and prefer
end tables since they fit nicely under
benches. My main bench is a converted
drafting table that I purchased from an ad
in a flyer. Since CAD programs are so
popular, drafting tables are going for
cheap right now.
You can also find great values at
pawnshops. It may take some diligence,
but you will quickly identify the ones that
have the cool things you need for your
shop. You can pick up table saws, bench
grinders, and drill presses for a fraction of
their original cost, and they are often
industrial quality—better than what you
can currently get from a homeimprovement
store.
I am always looking for photographs to
include in this column. If you have a photo
you would like to see in the column, you
may either mail a print or E-mail the file.
Contributions are welcome. MA
Tell them you saw it in “Modeler’s Mall”
08sig5.QXD 5/21/04 11:23 am Page 139
Edition: Model Aviation - 2004/08
Page Numbers: 138,139
Edition: Model Aviation - 2004/08
Page Numbers: 138,139
138 MODEL AVIATION
TANKS SEEM TO leak at the worst
time—usually when you are at a contest.
For this reason, it is a good idea to have a
flight-tested tank standing by at all times.
But even with a spare tank, it is not
always easy to make the switch; it
depends on the method of installation. In
fact, the potential of a tank leak can
increase or decrease with the method of
installation.
For several seasons, I mounted my
tanks using a bolt through the middle of
each. I loved how easy it was to change a
leaking tank. This was good because tanks
using this method will eventually leak. I
remember one particular Nats during
which Gene Martine helped me repair a
leaking tank each evening. Night after
night, he would preach about the way he
mounted his tanks.
I switched from using a single bolt
through the middle to using clear silicone
CONTROL LINE AEROBATICS
Curt Contrata, 6783 Nightwind Cir., Orlando FL 32818; E-mail: [email protected]
and balsa strips to hold the tank in place.
I also used silicone to glue the tank vents
in place where they exited the fuselage.
This helped support the vents, and it
reduced their vibration and the chances
that the vents’ solder joints would fail.
Tanks mounted this way never seemed
to leak. There was no stress on the tank,
and it could not move. It was also a
lighter method than using a bolt.
The downside was that when a tank
did leak, or if you needed to make an
adjustment, the repair and swap were
more difficult. Another bummer was that
neither a tank adjustment nor a
replacement was practical at the field
because of the silicone’s drying time. I
have been forced to fly at a contest with
a leaking tank because of the time it
would have taken for the silicone to
cure. Gene preached again, and I finally
listened.
His method is simple and requires no
special tools or skills. No modifications
need to be made to the tank, so an offthe-
shelf replacement drops right in.
Tank-mounting methods that require
pieces to be soldered onto the tank not
only make it custom, but they are added
points of failure. Besides, if your tank is
stock, there are spares available
everywhere.
By using two small strips of
basswood and a few small drops of thick
cyanoacrylate glue to lock everything in
place, field height adjustment and tank
replacement are options, even between
rounds. Not being one who likes to
The part labeled ‘A’ is the clip and the part labeled ‘B’ is the bracket. You will need two
clips and four brackets for this tank-installation technique.
Once the tank is in position, the clips slide into place and get one
drop of thick cyanoacrylate glue at each end.
To avoid failure of solder joint where vents enter tank, make a
simple brace from a small piece of tin to support them.
08sig5.QXD 5/21/04 11:23 am Page 138
overcomplicate things, I endorse this
method for its simplicity and
functionality.
The bill of materials includes a few
inches of 1⁄8-inch basswood and 1⁄2-inchwide
double-stick foam tape. In the
diagram, the part labeled ‘A’ holds the
tank in position; I will call that the clip.
You will need two clips that are 1⁄16 inch
shorter than the width of the fuselage, or
21⁄8 inches for an SV-type fuselage. Part
‘B’ is glued permanently inside the
model; I will call that the bracket. You
will need four brackets, and the side with
the notch goes toward the tank.
To install the brackets, drop the tank
into the fuselage without tank shims. Lay
a scrap piece of 1⁄4 balsa on the top of the
tank; it is used as a spacer. The spacer’s
thickness will determine the maximum
amount of tank adjustment you will have,
less 1⁄16 inch. Position the two clips on top
of the spacer, approximately one-third of
the way from each end of the tank.
Before you glue the brackets in place,
make sure they are facing the proper
direction. Both sets of brackets should be
positioned to allow both clips to be slid
toward the center of the tank for
installation and removal. This is important
since you may be unable to remove the
clips if the brackets are facing the spinner
or the tail. When you glue in the brackets,
be careful so you don’t accidentally glue
in the clips, or you will have a problem.
Apply the foam double-stick tape to
the underside of the clips, on the side that
will face the tank. The tape is
approximately 1⁄16-inch thick, and with a
1⁄16-inch shim under my tank, I used three
layers of tape under the clip.
Do you remember the 1⁄4-inch spacer?
Being that the tape compresses slightly, it
adapts to small shim adjustments and
applies light pressure against the tank to
hold it in place.
Don’t remove the paper backing on the
last layer of tape—the one that will touch
the tank. The clip will need to slide into
position and should not be stuck to the
tank. Since the tank is slightly narrower
than the fuselage, you can use foam tape
on the sides of the tank to fill in the side
play. Leave the paper backing on the tape
where it will touch the fuselage.
Since the brackets take up space on the
sides of the tank compartment, you will
have to maneuver the tank into position.
Start by sliding the fuel pickup through
the firewall; keep the tank rotated slightly
as you set it down into the compartment.
Once it is in place, rotate it on the axis of
the fuel pickup. The additional space
allowed by the spacer helps the tank rotate
past the brackets and into position.
With the tank in position, slide one of
the clips under the bracket. It should be a
snug fit but should not crush the tank.
With trial and error, you will see how
August 2004 139
many layers of double-stick tape you will
need under the clips. Let the layers of tape
stick to each other, but leave the paper on
the last layer so the tape won’t stick to the
tank.
Slide the second clip into position.
Place one small drop of thick
cyanoacrylate glue on each end of each
clip to keep it in place.
When you need to remove the tank,
press down lightly on each end of each
clip. When you do, you will hear a snap as
the cyanoacrylate breaks loose, allowing
the clip to slide out. As a precaution, I put
one small dab of silicone where each clip
touches the tank, to keep the tank from
moving around during flight.
The most common place for our tanks
to leak is where the uniflow vent and
overflow tubing enter the tank. This joint
is easy to reinforce with a small piece of
tin measuring 1⁄4-inch wide and 3⁄4-inch
long that is bent into the shape of a “J.”
Laying the flat side against the tank and
the curved portion under the vents, solder
it in place, and the chances of having a
vent leak are greatly reduced.
Similar to the method of using the
silicone, this will add support to the solder
joint where the vents enter the tank. The
problem with using silicone is that when it
does eventually leak, it is difficult to clean
the area to solder. I hate to give him credit
again, but Gene showed me this too.
Bargains are nice, and it is even better
when it is a bargain for something for the
shop. Drawer and cabinet space in my
shop is at a premium. My shop tends to
be dusty, and I don’t like to have
everything out on open shelves. I have
found it easy to pick up odd pieces that
provide enclosed spaces to fill in above
and below my benches.
If you keep your ears and eyes open,
you will be amazed by how much furniture
is given or thrown away every day. Office
desks are nice because they typically have
better hinges and drawer slides, and they
have heavy tops that can sometimes be
repurposed when the desk is disassembled.
You can really score when someone is
remodeling a kitchen; then all your
cabinets will match.
Bedroom furniture is nice; however, I
tend to stay away from dressers and prefer
end tables since they fit nicely under
benches. My main bench is a converted
drafting table that I purchased from an ad
in a flyer. Since CAD programs are so
popular, drafting tables are going for
cheap right now.
You can also find great values at
pawnshops. It may take some diligence,
but you will quickly identify the ones that
have the cool things you need for your
shop. You can pick up table saws, bench
grinders, and drill presses for a fraction of
their original cost, and they are often
industrial quality—better than what you
can currently get from a homeimprovement
store.
I am always looking for photographs to
include in this column. If you have a photo
you would like to see in the column, you
may either mail a print or E-mail the file.
Contributions are welcome. MA
Tell them you saw it in “Modeler’s Mall”
08sig5.QXD 5/21/04 11:23 am Page 139
