Motorizing the Revell 1:72 U-Boat.


>>From what I've read, some are trying...though I myself think the 1/72
>>kit is a bit small for this. But I don't see why it couldn't work. >>
>>Check out this FAQ, if you haven't seen it:
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> Thanks for the great link, especially useful on Sub basics.
>
No problem. Let us know how your R/C effort turns out!
Reply to
PaPaPeng
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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.
Reply to
Rufus
There is no proportional control in the Radio Shack sub. Just ON/OFF Fwd/Rev.
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.
Reply to
PaPaPeng
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?? :-)
Bill Shuey
Reply to
William H. Shuey
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 though.
Reply to
PaPaPeng
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? tia,
The Keeper (of too much crap!)
Reply to
Keeper
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
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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 white light. 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.
Reply to
PaPaPeng
also source of the term basking in the limelight.
Reply to
domjaime
Corrections:
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 RC toy.
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 model subs.
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 banked turn.
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 thr R-UB.
Reply to
PaPaPeng
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...
Reply to
Rufus
Thanks for the clarification! I think I'll try the calcium carbide route. Had a friend who had a nasty experience filling ballons with acetylene. Cheers,
The Keeper (of too much crap!)
Reply to
Keeper
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.
Reply to
PaPaPeng
Look up this webpage
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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 "Homepage"
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.
Reply to
PaPaPeng

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