Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Submarines => Topic started by: GG on March 16, 2017, 02:12:20 pm
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After a gap of some 10 years I felt like building another RC submarine. This time the aim was to create a simple design that did not require anything the average modeler might not have, material or skill wise.
The result is an admittedly rather "slab sided" hull but it seems to perform just as well as more rounded forms. Construction is mainly plywood with some balsa for the extreme bow and stern areas. The RC gear fits in a watertight box and the application of a bead of grease before securing a removable hatch keeps everything dry.
Being a dynamic diving type, forward motion driving it under the surface, only three RC functions are needed, rudder, hydroplane and motor. When set up correctly it will cruise around at "periscope depth" (only the top section of the RX aerial being visible) in a most stable fashion.
By having two free-flooding compartments, the 25 inch (63 cm) long hull weighs a convenient 4 1/2 pounds (2 kg).
No problems so far except when I take my eyes away from the "periscope" it can be damn hard to find again. Fortunately, stopping or reversing the motor has the model immediately resurfacing.
Plans just about to be sent off to the magazine "Model Boats". Now to think about the next model as I sneak unobserved around the lake!
Glynn Guest
[size=78%] [/size]
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Will this be for 40megs or 2.4 Gig things?.
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Big Ada,
Anything but 2.4 GHz which has trouble passing through water.
GG
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Son of Spook, GG?
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Rich,
"Son of Spook" only in general appearance and operation. Totally different construction.
GG
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Hope you don't mind, Glynn...I've posted this on our Facebook sub group.
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Having just built this little beast as my first ever sub I feel I must respond to this topic.
I built it as per plan but used any off cuts I had laying around in workshop so the sides are only 1mm ply and the wtc has a 5mm Perspex lid ( cut from an old printer hood).
Its maiden voyage brought lots of appreciative comments from club members but the little devil would not dive, other than backwards, needs more ballast was the result of much discussion.
The whole bottom was lined with a church roof and it was ready for its second outing (today).
Still it wouldn't dive but it was nearly there. Few bits of stick on lead were added and voila, it dives and potters along at periscope depth, still using 2.4 so dare not let it go any deeper.
This little sub has certainly got me and a few of my club mates interested in the whole sub culture so I must say a big thank you to Glynn and where can I get a 40 MHz radio?
I would add a photo but haven't figured out how to do it yet.
Thanks again Glynn.
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Congratulations Captain! It is a wonderful and unique slice of our RC world you jumped into! Glad you did.
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Really nice to see!
Concerning the "church roof" - model subs always feel really heavy - they need to be about as dense as water!
To reduce the carrying weight you can use "Velcro" (I use the self adhesive stuff) to fix sheet lead on the bottom of the model. It also lowers the centre of gravity, that way. It also means that you can move it fore and aft easily.
Happy sailing!
David
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Of all the different types of model plans published, Submarines give me the most worries. Other types, no matter how badly built and outfitted, can usually be made to float and go but submarine models operate on the proverbial knife-edge between success and failure. So, the smallest mistake when drawing up the plans and writing up the construction/operating notes for the magazine article could end up with streams of bubbles and complaints!
As for diving trim, these dynamic diving models have to have only a small amount of positive buoyancy. I ballast them down until the deck is almost awash (see first photo in this thread). This is sufficient for them to "pop up" to the surface when power is cut. Astern is best reserved for emergency stops, the models usually being uncontrollable when moving backwards.
Of course the joy of operating RC submarines is reserved for those who did not discard their "old fashioned" 27 and 40 MHz gear in the rush to use 2.4 GHz! The higher frequency radios might work if you can safely cruise around just submerged but dip too deep and.....?
So glad to hear of this success, any feed back is rare in this hobby (unless it's a complaint of course).
Glynn Guest
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I'm so pleased to see this thread, I started building Nixie 12 months ago, it was shelved for other "pressing" rc plane projects, and I started again last week. The plan is once running to turn the tower into a dorsal fin shape, as its intended to use with my Orca Jaws boat.
Please keep posting your progress, pictures and video would be appreciated
Paul
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What edition of Model Boats was this published in ? Anybody got a buckshee copy with plan ? Postage and small donation to a charity ? I feel a Red November coming on :embarrassed:
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It was in the October 2017 edition. Sorry not got spare because I'm building a slightly bigger version.
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Thanks Martin. That was my idea too. I was thinking 25% bigger would be my choice. Are you going to share a build with us ?
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There is currently an October 2017 issue for sale on The Magazine exchange site
http://www.magazineexchange.co.uk/model-boats-magazine-october-2017-issue.html (http://www.magazineexchange.co.uk/model-boats-magazine-october-2017-issue.html)
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Thanks Tony, I just bought it :-))
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I don't think my build would warrant inclusion in these hallowed pages, or to put it another way, I'm a bit of a bodger, more interested in it working rather than the way it looks.
I've got to get my head around putting pictures on the site, if I crack that obstacle then I may have a go.
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I don't think my build would warrant inclusion in these hallowed pages, or to put it another way, I'm a bit of a bodger, more interested in it working rather than the way it looks.
I've got to get my head around putting pictures on the site, if I crack that obstacle then I may have a go.
Makes no difference we love to see pictures of anything model building related....
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Its time to finish what I started 3 years ago, so the bag of Nixie bits, and the magazine with the plans, are back out of the attic, and its back on the workshop bench
Anybody else built this and got it running? pics would be good!
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Hi ,
try spook uboot on Goo... and you will find a lot of pics.
According to this forum and otheers this boat is well known in the world, thanks to Glen.
b.r. Sven
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Some pictures I have of a modified one.
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Have to admit it's nice to see that the "Spook" sub design has been successfully built by others. There's always a worry that something important has been left out of the construction article/plan.
Have to admit that my favorite sub is the smaller Type XVII U-boat. Current sat on a top shelf, only needing a recharge before sailing (whenever that might be possible?).
The latest sub design, based very loosely on the type 2 and 7 U-Boats, fortunately came through it's shake-down runs successfully before "lock-down". The hull design is a simple free-flooding type with a central watertight compartment for the RC gear. Construction mainly plywood and no elaborate workshop is needed, just the skill to cut accurately and make make sound glued joints.
Glynn Guest
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just the skill to cut accurately and make make sound glued joints.
Glynn Guest
Well that's me knackered then {-) {-)
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and me :embarrassed: , my waterproof box is currently waiting for the resin to harden in the gaps! I just cant do wood, plastic, depron, metal, no issues, but wood, just cant get on with the stuff
GG, that smaller sub would be ideal, as I only want an rc dorsal fin to accompany my Orca (jaws) boat, before I go much further with Nixie (all parts are cut out, and the box is built) is it just a scale down ?
thanks
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I always regarded the people that had mastered RC Submarines as having some sort of mythical superpower, having conquered the dark art of sinking an rc model, and retrieving it, with a degree of control and direction. The models are stunning, and my wishlist would be nautilus, flying sub (and it would have to fly as well as submerge) stingray, probably in that order, then a large U Boat.
So way down in the list of scale representations, comes my wish for a rc dorsal fin, its as simple as that, it must go left and right, dive, maintaining fin under water, and surface run. I've attempted this many times, and its the one thing that keeps beating me. The last attempt was a model supplier going back a couple of years who marketed a small simple submarine. Unfortunately no evidence of success could be found, and my attempt was also a failure, then Nixie appeared! so lets hope this is more successful.
The last attempt had been in the loft for a few years, so today it was rescued, I have a 40meg tx and rx, receiver, small brushed motor, some micro servos, a selection of pushrods etc, enough to pretty much complete the running gear, only thing missing is a brushed motor esc.
I'm a bit embarrassed posting in this thread, my feeble attempts to join the rc submariner Gods, but when posting a build, it keeps me interested, as I have a very short attention span when building things
If anyone can offer advise along the way, please chip in!
So tonight made a motor mount from some scrap aluminium, laid out the propshaft, and used resin to fill the gaps from my poor wood cutting skills. The propshaft wasn't level, the mount was a few millimetres high, so I enlarged the hope in the stern of the watertight(we hope!) box, and will epoxy a plate on the inside holding the shaft level
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Someone mentioned Shark
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And a different one
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does it submerge though?
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Can just see all the news reports now in your area {-) {-)
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bit more tonight, only prob is its looking too big! need to scale down the coning tower/fin! when completed, I know Jaws was big, but it might be too big sailing next to the boat!
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It doesnt submerge, the fin is carved foam. I was worried it would stick in the river bed. I did think about making it with sheet plastic sides instead with flood/drain holes
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It actually gave me a creepy uneasy feeling seeing it in the river, even though I knew it was just a model.
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If you want it to submerge it's best to make the fin hollow,from material as thin as possible, and free flooding.
This keeps displacement down reducing the size of the ballast tank or the speed required to submerge if you're making it dive dynamically
Fibreglass takes some beating, specifically thin cloth and epoxy resin. You could carve the fin from polystyrene foam, skim over with epoxy and a layer or two of thin 25g glass, and then melt the foam out with some acetone once the resin has cured.
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Ill do my fin that way, I was wondering about exit holes though, so when it surfaces the water will escape?
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You'll need a vent right at the tip to avoid trapped air. Minimum size hole 3mm (1/8") or thereabouts, or make a slot of equivalent area if you can't make a circular hole that size. Any smaller and water tends to skin over the hole after the first submergence, and that bungs it up.
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And flood holes or slots at the base as well
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It can be left open ended at the bottom, so mount it so it's slightly above whatever structure you're attaching it on to.
Bear in mind if the fin is very large you can expect it to cause significant roll on turns.
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speed controller arrived today, looking at it (and the £10 price tag!) I think the claim of "waterproof" and 320a are a big exaggeration! %% %% , and the 60a sticker on the case! {-)
those Chinese factories that churn out these cheap products certainly have a sense of humour.
On a similar subject, I'm surprised at how much "decent" makes, such as Mtroniks actually cost, given that brushed technology certainly is the outdated technology, I would have much preferred one of those, but the price is well out of balance compared with brushless, and the fact that the maiden sail might end up at the bottom of a lake I didn't fancy that financial loss
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plodding on!
I've not done this in a while!
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because I did a man read of the instructions right at the beginning, I had the water tight box upside down, meaning the internal frame was too big. I ignored this, but had forgotten how much bigger then 40 meg receiver is compared to 2.4 receivers I have been using for the last several years, and the esc is the size of a house brick compared to brushless esc, that's before we start on how much bigger a nimh pack is compared to a same voltage lipo, so I had to remove a lot of internal wood to make things dry fit :embarrassed:
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Plenty of paint to help stop rotting wood!
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running gear in, dry run all works, but nowhere near enough elevator (or whatever its called on a submarine!) deflection, need to rethink that as I'm all the way on the horn holes. Also I was hoping to just attach the servos with double sided tape to the hull sides, but they are moving, cant glue them in as they will invariably fail at some time, and I don't want a complicated mount, this was supposed to be an easy quick build {:-{
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The receiver aerial, I've read the build log that was in the mag 3 years ago over and over, but I'm not sure what to do. I was thinking it would be a plastic hollow tube, with the aerial wire inside it, and out the top with epoxy at the base to stop water getting in. The build says use a plastic coated wire? not sure what this is, and how the aerial wire is attached, I'm very reluctant to cut the wire on the receiver, and suggestions? can the receiver wire just stay inside the water tight box?
So far pretty much nil from the submariner fraternity, so hopefully someone is looking in to help out please!
Next question is the Perspex top to the water tight box, I have some neoprene foam strip, seems a shame to use screws, as the holes themselves will create more opportunity for water leaks, I found some waterproof tape at prestwich models, will this work better, the battery is inside the box, so every time I recharge its a load of screws to take off, and if the neoprene foam fails then its just a thin bead of grease keeping the water out, any suggestions on this please?
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If you keep the aerial bunched up inside the hull this will reduce range. I have a shark where I've done that, it's fine for up to about 20-25 feet on 27mhz but beyond that I lose signal (I've just changed this to a 40mhz set but haven't been able to test it yet). What I did on a couple of other models was is one case run the receiver aerial up inside some plastic tubing sticking up above the model, a bit of grease or silicon on the tube to keep water out. On the other model I used a bit of piano wire as a whip aerial, cut the reciever aerial short so the total length was about the same and soldered the 2 together where the piano wire came inside the hull.
For charging, could you fit a small hatch into the perspex top (maybe 4 bolts to hold it) so you can reach the battery connector without taking the whole top off?
Good luck with the rest of the build, been enjoying this thread.
Ralph
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Hi Ralph
thanks for the ideas. I've been thinking about the hatch idea, and decided that removing a load of screws from the Perspex plate on the dry box will be a real pain, and then on replacement will need to be re greased to stop water ingress, I'm club fingers so this will get messy, so thinking about the hatch idea, I've made up a charging lead from the battery with a simple two pin connector which will be inside the watertight box. From the top of the box I have two leads that will be permanently hot glued going into the box, so effectively I have a permanent charge lead outside the box. If I do need to remove the Perspex plate, I can simply disconnect from inside. I'm going to use bullet connectors, as these will be easy to make some sort of cap to stop them getting too wet and getting corroded.
Not yet decided on the aerial, I still cant understand what Glynn Guest meant on his description of the aerial fitting in the model boats mag build description, I think the hollow plastic tube is the easiest way, and you then are not cutting the aerial, but there must have been a reason for the way he did it. I've tried to stick to the original plan as much as I can, why deviate as GG has done all the testing etc, and he knows what he is doing :-)) [size=78%] [/size]
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I would advise you to test out your hull's watertight integrity with all equipment removed.
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ah!
yes good call! :-))
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If you're going to charge the batteries in situ, then make sure you have a means of venting the enclosure. Otherwise you have a potential pipe bomb.
Epoxy resin would have been the best choice for sealing the wood. As well as sealing, it also increases the strength. Paint adds no strength, and over time the water tends to permeate through it.
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"most" :D surfaces did get a coat of ronseal exterior satin varnish, then paint, so too late now to epoxy unfortunately
servos now reinstalled with mounts so fixed better in place, this did mean the servo rods now need to have a bend to mate up nice with the servo horns, deflection on control surfaces is now acceptable.
The frame is now curing that the Perspex plate will go on, not for initial testing, but once its been water /leak tested Ill put a vent hatch on the Perspex plate to allow the fumes out when charging. I want to have as little as possible with potential leaking points at the test stage
I'm still on the fence about the aerial, it would appear that the more solid piano wire or similar actually helps with the diving, so the hollow plastic tube with aerial wire up it might fail. Just got to think of a way of securing it to the Perspex plate, with enough inside to solder the aerial wire to?
With regard to the tower, is that actually functional? I'm thinking does the volume of water that goes inside the tower when submerging actually help, as its eventually going to be a dorsal fin I wasn't going to bother making the tower, just test then if it all works, make the fin
thanks
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It'll be fine inside the hull, that's the way I run them.
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it got wet today, and happy to report no apparent leaks. Before resorting to grease, or petroleum jelly to seal the Perspex top plate, I found some one side adhesive foam tape, I recall I must have bought this 3 years ago for this project, so thought I would give it a go, and it seems to have worked.
I've cut a square out of the top to allow the battery to be charged in situ if necessary, this will let the fumes out, although if the tape does keep performing, this makes the Perspex top plate much easier to remove. .
I was still unsure about the aerial, the instructions are not very clear about this, so had a choice of an old transmitter aerial, or the whip style in the picture, the latter has been used as it was a very easy fit, hopefully it will work.
Next stage is ballast, without ballast it wants to roll over in the bath water, hopefully that will not happen with ballast, then a range test and get the servos operating, and check the propshaft doesnt leak when in use, then its lake time ;)
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bath trials have gone ok, it is really difficult to get the ballast right, is this normal with rc submarines?
I've got 360g, front and 380g at rear, which seems an awful lot, Glyn Guest in the build commented he used a few coins to get his decks awash and ballasted. I also noticed that the slightest of movement and it all goes wrong, and if the decks are not wet, its very unstable. I need to think of a way to attach the lead in an easy fashion, making it easy to add or removed at lakeside. I though of a bolt front and rear under the hull, and just use a wingnut to hold varying pieces of lead on, will this then create too much drag under the hull?
I have also had to change the prop, even in the bath when power was applied it was just a lot of cavitation and no movement with a 3 blade prop, I've now got a 45mm two blade, which moves it, but still a lot of cavitation, and this is running on a fresh 6 cell nimh. Ill have to rething the ballast securing, and then its to the lake, and hopefully not just a sink to the bottom!
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Ballasting is always tricky with model subs - part of the "fun"!?
I use Velcro to attach external weights. (Apply a strip of self adhesive Velcro tape to the bottom of the hull. (Drag isn't a problem at normal sub speeds)
Prop selection is also often tricky and also interacts with ballasting. The prop can draw air in from the surface - this isn't actually cavitation. Keep the stern down in the water. Go for a low prop speed if you can - gearing perhaps?
Have fun and good luck!
David
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Ventilation is a problem with any spindle sterned sub because there is no hull bottom acting as a shelf above the propeller. Once you get below the surface approximately one or two props diameter, you'll find the problem disappears. Use the throttle sparingly when on, or near the surface to avoid the 'egg whisk' effect.
Adding a fixed or swivelling shroud/kort nozzle will help in reducing ventilation, but won't eliminate it. If you look at earlier submarines that were primarily restricted to behaving like submersible cruisers, and thus had to spend the majority of time on the surface, they tended to have the props mounted much lower and as far underneath the boats hull as packaging permitted.
Once subs could remain submerged for much or all of their patrol with the advent of nuclear and other AIP systems, the design constraints shifted and spindle sterns became the norm, where they are sited very efficiently with large diameter props that are less noisy.
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My stretched And modified Nixie was ballasted with a sheet of lead forming the whole bottom and it still needed a couple of extra ounces added.
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thats a cool nixie Martin! I had not thought of opening up slots etc front and back top plates
If I had been wiser Davy, yes gearing, but too late now, I was treating it like a conventional boat. What are the thoughts, much larger prop diameter, more prop blades?, Im considering what Subculture has explained, I called it cavitation, but in hindsight it was different to what I have experienced previously with boats, If I go larger diameter prop, it will have to submerge more to get the prop underwater :embarrassed: its quite technical this submarine stuff!
Strip of lead full length, what a great idea, then try less ballast front and back, worth a go I suppose
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Attach the lead to the outside of the boat using rubber bands, zipties etc. slide back and forth until you have the right position for trim, then attach inside.
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for God's sake!!! :(( :((
so I've been on other tasks, with rc plane sites reopening, and very favourable weather, I've been playing with them. Ba[size=78%]ck to Nixie, all ready for the first real water test outside, and I connect the battery up reversed in the tx and the smell of electrical death came out of it, so now I need a transmitter and receiver[/size] >>:-(
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"smell of electrical death". {-) {-) {-) {-) {-) sorry but its a great expression !
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its a bonus if it also releases a deathly black cloud, which follows you almost laughing at you, then you know your device is well and truly dead, when its just the death smell you always feel there is a chance of resurrection, bit like a steven king film.......... :embarrassed: