Neat idea - all the parts in one package.
What you are describing is a somewhat corse proportional R/C control.
If I understand what I read on the SubCommittee FAQ, I would set your
U-boat up as a dynamic diver.
If I understand things right, that should mean you only need two
positions for the diving planes - one to dive, and one to trim for
surface running - and a proportional speed control. This way, the
faster you go, the deeper you dive, and vice versa.
The one thing I couldn't gather was were they say to trim the boat for
neutral bouyancy as a dynamic diver...not sure just what that means in
terms of waterline at dead stop.
There is no proportional control in the Radio Shack sub. Just ON/OFF
The way that works is probably the motors, preset to push down, will
drive the sub forward (reverse or stop one motor for turns) just below
the surface until the antenna fades. The Revell UB size is not large
enough for static diving hardware. In any case static bouyancy will
be too ambitious for a first project.
The instruction booklet says go no deeper than 1 metre. The RC sub
group says RC transmissions can be received underwater. So that 1
metre control may still be possible.
My proposal to add logic gate chips is to get that proportional
control with latching (to eliminate jitters from unsteady finger
pressure on the controls) and also to get more run time by separating
the motor battery power from the battery for the Rx.
Neutral bouyancy I believe is to add flotation mass (styrofoam or
wood) to get the sub to float with as little freeboard as practical.
That way it wouldn't require so much power to dive using forward speed
and preset hydroplanes. And it wouldn't pop up so fast once the
control signals fade.
The RS sub's Tx has a flexible PVC molded antenna. I wonder if this
is meant to be immersed to control the sub when it is submerged. The
Tx itself can probably be sealed in a clear plastic bag, The Tx
controls are membrane switches and will present no access problem when
sealed inside the plastic bag.
Great! Now all I have to do is figure out how to add working depth
charges to the Revell/Matchbox Corvette! I could base it on a
"hammerhead" with some lead weight, but how would I light the fuse??
Don't laugh. Perhaps pack quicklime (CaO) in a "depth charge"
canister. When dropped into water it reacts with water to produce
calcium hydroxide and hydrogen gas. If your canister can contain the
gas until bursting point you may have an underwater burst that spews
out white powder and a lot of bubbles for effect. Won't sink anything
Great idea! This is the same as slaked lime right? Before electricity it was
used in miners helmets and vaudeville halls. It gives off a eerie green glow;
performers used to sit in a room with this light before going on so their eyes
would adjust. Hence the term "green room."
Where would you suggest I go to buy some?
The Keeper (of too much crap!)
Calcium hydroxide is the slaked lime. Slaked lime was used as
whitewash on walls.
You can make your own quicklime (calcium oxide) by burning seashells
or limestone (calcium carbonate.) The lab suppliers sell only
analytical reagent grade CaO and that'll be too pricey.
I am not sure about the light being green. I believe what you are
referring to is calcium carbide . See
at Calcium-Carbide.com, we make it easy for you to purchase calcium
carbide for your lamps, cannons, experiments, etc. We currently offer 1 lb.
packages (gross weight) for purchase, with or without insurance.
CaC2 with water generates acetylene gas which burns with a bright
In WWII U boats would discharge cans of acetylene in order to generate
a mass of gas bubbles to provide a false sonar signal.
Calcium carbide may be easier to buy than CaO.
Yup,my original purchase didn't work because of the most elementary of
oversights. My AA cells were spent because I left them on in another
Hookay. The Radio Shack "Mako" mini-sub has more built-in useful
features than I had suspected.
1. The center button turns ON the Tx. This sends a continuous signal
to the sub to run both motors forward. There is no reverse. It will
remain latched on run until you toggle OFF the Tx.
2. There are four buttons in the N-S-E-W positions.
3. Tx ON. Both motors are running
o. To make a left turn press the left buttton and it will
stop the left motor. Since the right motor is still running it will
cause the turn. The moment the left turn button is released both
motors will run again to return the Mako to a straight direction.
o. ditto for the right turn.
o. The bottom "down" button rotates the two motor pods
almost 90 deg down. It will stay in that direction with both motors
running until the button is released.
o. The top "up" button rotates the two pods 30 deg up and
stay there until the button is released.
4. When submerged the motors "burp" I think because of the Tx signals
being faint. Immersing the flex PVC covered Tx antenna improves the
signal strength. I had been able to check this out in my bathtub
only. The park's pond was too weedy.
The speed underway is barely walking pace but so long as it moves the
Revell UB, can be steered somewhat, maybe able to dive, I will be
satisfied. The slow speed and the wide turns of the Mako are perhaps
more scale-like than the full dedicated RC hardware installations in
An idea for the rotatable rudders will be to link the pair with
rearward tillers and add a pendulum. The pendulum will self center
the rudders as well as tilt them in harmony with the direction of a
The other idea is to point the R-UB hydroplanes slightly down so that
the submarine remains submerged so long as there is forward movement.
The Mako's motor pods are already preset slightly down for the same
purpose I suppose.
I haven't opened up the Mako yet to see if the motor pod rotation can
be adapted and linked for the R-UB's hydroplanes. But one necessity
will be to make stronger hydroplane guards and attachment points in
Large, empty gelcaps from your pharmicist - they disolve in water. Put
a small lead weight in one end, fill with CaO, maybe a pinhole in the
other end, seal with CA...POP!
Up to you to design the launcher...
I forgot about seeing submarine conversions that needed oversized bow
planes. Yep. The R Shack Mako minisub certainly won't go forward
fast enough to dynamic dive, especially with the scale bow planes.
But here's the latest.
I took apart the Mako mini sub to see its guts.
The sealed motor pod is 1 inch diameter and has a 1/2 inch post that
allows it to be rotated on its axis. The R-UB's propeller shafts are
1 3/16 inches between centres. I can probably get a 1 3/16 in.
thickness plexiglas sheet to use for the motor mounts. Staggering
the motors will likely solve the problem of aligning the motors with
the R UB's propeller shafts, a 1/16 in. difference.
I'll have to find a 2 inch cap to seal both ends of the cylinder that
houses the electronics, the servo and the battery pack. This module
will be a cylinder 7 inches long and 2 inches diameter. There is
sufficient room to fit this cylinder inside the R-UB.
The widest part of the R-UB deck is coincidently 2 inches. Dry fit
tests. This will allow the cylinder module to be tilted up to remove
the battery pack and also to drain any water leaked in. But once the
cylinder module is installed in the R UB I won't be able to take it
out unless I pull wider the hull plastic in the process.
The servo axle is transverse mounted to swivel the motor pods up or
down. I was scratching my head as what to do with it as linking the
servo to the dive planes would be too complex a job if at all
possible. Then this idea came up. I would use it to move a paired
float + weight parallelogram, something like a pantograph. The top of
the pantograph will be floatation material and the bottom the ballast
weights. To dive the bottom ballast is shifted forward and the top
float backwards. The the trim of the sub will be shifted to the
direction required while forces on the pantograph should balance out
to give smooth operation. To raise the sub the pantograph geometry
is reversed. If there is no Tx servo input it will return to its
neutral position. Adjustable stops will be used to limit the throw
of the pantograph and therefore the trim of the sub.
I have to position the cylinder module backwards to minimize the wire
run to the motors. Coincidentally and happily the servo rotation to
the pantograph will now correspond to the Tx commands.
The scale diving planes will be free to swivel, but will be held in
alignment by a weak spring (from a floppy disk shutter spring.)
Everything might just work out. But as RC Boater says, seeing the R
UB moving on the surface is probably fun enough.
On the left sidebar go to the item "Sources."
In the box with a listing of "Components" go to
"Submarines" and click on its highlighted
You will see a picture of a UB VIIC moving in the water.
Click on the link there.
A German company already has a motorizing kit for the Revell U-Boat
VIIC. Looks very good.