Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Submarines => Topic started by: bobk on March 02, 2011, 11:51:54 pm
-
Ever since seeing a shipwrights model of a K Class submarine in the Imperial War Museum, many many years ago, and avidly reading everything I could about these unique boats, I have always wanted to build one. So much detail and working parts.
Having found a source for the 53" long hull mouldings (Deans) and detail plans (John Lambert Plans) it is finally looking to be a realistic goal. I would like to ask anyone out there who has travelled this road some questions please. . . .
a) With the very narrow beam (4.25") & hull height of 3.5" is it possible to fit a Engel type static diving system? If so which one would you recommend.
b) Has anyone fitted RC retractable funnels to a K Class? Any info appreciated.
c) I would love to track down that original 1914 shipwrights model again, anyone seen it?
Many thanks
-
Will be watching this with interest, ive got the same plan set as you, and also looked at that hull. In mean time im awaiting delivery of an M1 hull which is similar size.
I think it will be near impossible to get Engel tanks in her, you will need some other ballast system, at that scale. I have been working on the Revell type VII for some time and had difficulty getting a RCABS system to work well, so ive bitten the bullet and going for a gas based system using D&E miniatures (Dave M) sub driver. Once i have both in my hands im going to measure what displacement the M1 needs and see how that compares with the Type VII sub dirver. I suspect im going to fall a little short of achieving scale a waterline, will let you know once i have the hardware. I'm then going to decide whether to accept the shortfall or get a second larger subdriver. Others may be able to offer some other constructive advice, but form what ive found in long narrow hulls the gas system seems the safets route. YMMV
As fas as top sides you of course have the funnels to worry about, i have the big conning tower and gun.
-
Thank you Albion. I thought the hull looked narrow, despite it's 53 inch length, but could not find any dimensions for an Engel (or similar) static diving system. This looks to be a real challenge, especially as I want to keep to realistic looking speeds then dynamic diving is out.
Your M1 project sounds wonderful, please keep me up to date with progress. I understand that M2 was converted into an seaplane carrier, and M3 a minelayer.
PS: I see you are in Singapore. I have many fond memories of my visit there :-)
-
Give Big Dave in the USA a shout http://www.frontiernet.net/~bwelch/
He sells WTC kits and he was going to be building a K class sub a few years ago so should be able to help out
-
but could not find any dimensions for an Engel (or similar) static diving system. This looks to be a real challenge, especially as I want to keep to realistic looking speeds then dynamic diving is out.
Glad you enjoyed Singapore, i came here for a two year stint, and have been here 13 years now!
The Koryu, Japanese sub in my avatar uses a piston tnak, but whilst not engel, it is similar size, that menas a 75mm OD piston. the drive motor is offset and adds 12mm to the max diameter. they have a new design which is fitted to the new Type 212, and that has the drive motor within the piston tank diameter, saving space, but still too big (77.5mm) to really fit into a 1/72 hull of this era. There is a company called Piranha who are producing small diameter pistons tanks, which might work.
-
A very interesting project.
The only working K class I've seen was brought to the Barrow in Furness MBC a couple of years ago. It worked very well but I don't think it had retractable funnels!
I placed some video footage of it on the Association of Model Submariners Facebook site and the Forum site.
Sorry I don't have a link for it but contact me if you have trouble finding it.
David
-
Many thanks Albion, I will try to find more info on the Piranha systems for this very 'slim' hull shape.
Thanks also to Davy1, some really iteresting info on that Facebook group, which I have now joined. I have not found the video yet, but will keep trying.
Thanks to Davie Tait. I will email Big Dave as you knidly suggested.
At least if I do succeed in completing this K project I probably will not see dozens at the first sailing meet I go to !
Once embarking on a 1.35 m model of a stem powered submarine how could I not consider retracting the funnels before diving, that would look SO cool. :-))
-
Piranaha's small diameter piston tanks (45mm dia) only go up to 200ml as they are designed to be trim tanks. Thomas will make you any size you like but the tanks going to be rather long at diameter to hold any useful volume. I'd go with a sealed ballast tank like what Sheerline uses or a water pump puming into a badder. You can easily but this together your self for little expenditure.
-
K1 quote from Officer in bow compartment on telephone to Officer in engine room "I say, No 1, my end's diving - what's yours doing?"
Also remember the battle of May island.
-
I found those videos from Association Of Model Submariners: Thank you.
http://www.facebook.com/home.php#!/video/video.php?v=1177076634979&oid=42806976104
http://www.facebook.com/home.php#!/video/video.php?v=1240054369383&oid=42806976104
Really nice, very realsitic. Great job!
On seeing how it answered the helm I was reminded of another quote from 'K Boat's in which there were described as "having the turning circle of a battlecruiser, but with the navigational facilities of a picket boat". Looks like it will take both skill to build, and skill to sail.
-
Looks like a bit of a CG problem, heels over a lot in the turns.
Thanks for info Ramesh, i think it might be possible to squeeze two in, but so many compromises to make that work in this size of hull
-
As this boat has a lot of freeboard you could look at a hybrid ballast system.
A snort system would work with those natty little diaphragm air pumps you can get for a few beans. You could combine this with a small trim tank sized to 10-15% of your overall volume required. That could be based in any number of technologies, a small piston tank based on a syringe is one possibility.
I've also found an ebay source for small, brushless centrifugal pumps, which are used in coffee machines of all things. With a vented main tank and smaller trim tank these could work well, as they shift a lot of water very quickly.
So you can blow or suck depending on your preference.
To improve turning consider a removable front rudder. If you make it from lexan or acrylic, it will be invisible in the water and will greatly improve agility. Some people use thrusters, but they only work well with the boat stationary, and look most unscale like for a model of this vintage.
-
Hi Bobk,
Sorry I my have confused you about the K class. I have posted videos of two of them. One is at Edinburgh MBC and is owned by Andrew G. The other one was brought to the Barrow MBC sub day in 2009 and was just brilliant.
I've reposted the video for you on the AMS Forum:
http://www.theassociationofmodelsubmariners.com/t293-k-class-r-class-and-type-ix-at-barrow#1119
She handled very well I think. Nice turning circle with only stern rudders. She had a gas ballast system (nothing complicated) and an epoxy hull. Hence light and easily carried.
The R class is my own humble attempt!
Best of luck with your K project.You wait for one and then 3 come all at once!
David
-
Here's a link to the little centrifugal water pump I mentioned in my previous post- http://cgi.ebay.co.uk/Mini-Water-Coffee-Pump-24-GPH-P-25A-DC-12V-/250722722777?pt=Small_Kitchen_Appliances_US&hash=item3a603d23d9
The same outfit do a whole range of brushless centrifugal pumps in various capacities. Could suit just about any size of boat. Prices are very competitive I think.
-
Many thanks everyone, some really useful information. I know a lot more now than a week ago.
I think I need to explain where I’m at :-
I used to love scratch building models, from a fully sectioned Apollo Command / Service module (from plans & photos), some unusual slot racing car replicas making my own vacuum formings, and a nearly 3 ft long wood hulled model of HMS Cressy powered by a Mamod marine steam engine. However, that was many years ago.
I hope I am not 'out of my depth' here, never having built a submarine, or even seen one except on video clips. Maybe I need to go to some events and meet submariners. Whilst I have every confidence in building a very detailed ‘dry’ display model of a ‘K’ I would really love to build it as a fully operational boat, without replicating the first voyage of the K13 (lost on trials).
It appears that I may have to design and build a complete bespoke static dive system and ‘tech deck’, rather than adapt an existing professional system. I reckon I could need around 1.5 to 2.0 litre ballast volume. At least it’s fortunate I have a very large Koi pond for testing purposes.
-
I think 1 litre should be plenty, as long as your not building it as a dry hull. A lot will depend on your desired waterline and how low you can mount your water tight container.
-
I dug out john Lamberts k class plans, and you are going to need the WTC to fit between frames 151/170 back to 69. Thay gives you a length of about 600mm, maybe a tad more, but really limiting the od to 2" (50mm, 60mm at a stretch). Anything larger than this will be above the waterline, and not offer any benefit. I have similar limitations, but probably not so much to lift.
-
Albion, you have a PM.
-
...a fully sectioned Apollo Command / Service module (from plans & photos)
Bob, I would love to see that. Any chance of some photos in a new chit-chat thread?
(Though with the Apollo CM capable of floating, perhaps it could pass muster as "a boat"!)
Andy
-
I reckon I could need around 1.5 to 2.0 litre ballast volume. At least it’s fortunate I have a very large Koi pond for testing purposes.
That sounds like an awful lot of volume for that size of boat. I'd have thought 500-750ml would be nearer the mark, unless you are retaining a lot of dry space above the waterline.
If you're going for a vented tank, you could build a centre tank that utilises the hull, this will maximise width and reduce length- you'll get a lot of volume in a small footprint.
-
Sorry, I never kept photos of HMS Cressy, It got as far as pond trials (without superstructure etc) when I found the steam engine drove it far too fast, despite being sized well over the "suitable for boats of 2 foot or more" quoted. With only RC rudder control I never was able to limit its speed record attempts.
Attached is my 35 year old Apollo 13, the CM of which was an ocean going vessel - of sorts.
(http://s1.postimage.org/34mrod4jo/Apollo_b.jpg) (http://postimage.org/image/34mrod4jo/)
(http://s1.postimage.org/34muzftj8/Apollo_c.jpg) (http://postimage.org/image/34muzftj8/)
Whilst a fully sectioned 'K' would keep me occupied for a very long time, I would prefer a working version. Totally different challenge.
PS: That Dreadnaught is Awesome !!!
-
Bob, that CSM is lovely.
I remember seeing one CM (Apollo 10's?) when it toured the UK in 1970-something, and I - as a young boy at the time - remember most vividly just how small the thing was. It's remarkable, on reflection, that 60's technology got off the ground, let alone to the Moon.
Thanks for the kind words on the Dreadnought. Building will recommence once I've got Racundra sailing.
Andy
-
Is this the model you were talking about - I was more interested in the landing craft at the time but the K class does have its attractions?
(http://i306.photobucket.com/albums/nn261/FrancisMcN/Pict0138.jpg)(http://i306.photobucket.com/albums/nn261/FrancisMcN/Pict0139.jpg)
-
That looks like the shipwrights model I saw ! Where did you see it please? It does not appear to be on display at the Imperial War Museum any longer.
PS: A perhaps naive technical question. If I have one (or two in parallel) ballast tubes with plungers, if they start off full of air, what happens to the boats trim when the plunger is half in and the 50% at the front end is full of water whilst the rear 50% is still full of air. How do you stop the boat nose diving?
-
Turn one pluger around 180 degrees to balance out the other.
-
That looks like the shipwrights model I saw ! Where did you see it please? It does not appear to be on display at the Imperial War Museum any longer.
It was one of the old Model Engineering Exhibitions but I can't even remember if it was at Olympia or Alexandra Palace.
It might be worth asking the IWM if there is any possibility of access at some stage to the model or any plans to pt it on display again.
-
That model looks identical to the one at the RN Submarine museum at Gosport.
(http://s2.postimage.org/18hn7pqjo/DSCN1827.jpg) (http://postimage.org/image/18hn7pqjo/)
-
There is a photo of a K class model in the latest issue of "Model boats."
I think it is in the feature on the Sandown show, if I remember correctly.
(it is funny how once you start looking they pop up everywhere!)
-
No, the problem was that they didn't "pop up".
-
Manny thanks everyone. www.rcmodelsubmarines.co.uk is an amazingly informative site, and has greatly helped my appreciation of what I am getting myself into. It appears that with a hull of these proportions I will need two ballast tanks, fore and aft, with a proportional control system to effect trim. Perhaps an automatic trim control to counter the K's natural disposition to seesaw / nose dive. Sad there seems nothing 'off the shelf' to fit a 53 inch hull with only approx 4 inches i/dia and just over 3 inches i/height including keel.
Maybe I should look for a system designed for smaller boats, fit one small tank forward, one aft, with a third admidships on a separate channel for emergency surface (similar effect to the K's droppable keels). The volume and complexity of electrics looks vast. As most of the hull could end up as WTC I will need to cast some metal ballast to fit into the keel space.
I aim to visit the Submarine Museum at Gosport, contact the IWM, and subscribe to Model Boats. Advice appreciated.
-
I think you will be fine with a single ballast tank, and it doesn't really need to be proportionally controlled (though that is the gold standard). A single ballast tank sysytem is something you can easily make your self with a reversible water pump and a bladder from a blood pressure cuff. A horizontal trim system is a good idea, as their is a lot of superstructure that will creat drag when under water and alter the pitch of the sub.. A sevro than moves the battery (or a weight) a couple of inches will be more than enough.
Oh and thanks for the plug :embarrassed:
-
Have you got a lathe, Bob?
Also get this book- http://shop.traplet.com/product.aspx?c=294
and also have a look at this website-
http://www.heiszwolf.com/subs/tech/tech01.html
-
No I don't have access to a lathe, although I served a 5 year apprenticeship as a toolmaker. One reason I have tended to model with ABS & Perspex etc.
I think my best approach is to try to design and build a ballast tank system, plunger style, of a diameter able to fit the hull, although it still appears that as it fills from one end the fore & aft trim is going to shift massively. I like the idea of using the battery as a servo-movable trim weight. Once I have that working and watertight I can then start on motors and control surfaces in a separate WTC. The whole assembly will need to be adjustable to determine 'neutral trim' before going any further.
Frankly, I would like to see something working first and discuss it to avoid an expensive hit & miss series of learning curve experiments. A lot of time and cost that could easily end up in a terminal sequence of ripples with a final bubble or two. The risk of total loss is very high. <:(
PS: Has anyone else used Gyproc coving adhesive, a totally amazing modelling media for creating smooth blended curves and surfaces. Smooths with a damp cloth. Sets like concrete with a silky finish.
-
Hi Bobk,
Thinking about what you are planning to do, I would suggest a fairly conservative approach to what will be your first submarine.
Build it first as a surface runner - it will look super anyway.
Leave at least a "1 litre shaped hole" just under where the periscopes will be. You can fill this with whatever ballast tank system you choose at a later date.
You can get guidance on different ballast systems from many sources including:
http://associationofmodelsubmariners.com/
Keep your superstructure as strong and light as possible but with as little displacement as possible.
A lot of advice you will be given is from people who have never scratch-built a submarine - it can be a steep learning curve.
Hope this doesn't pour cold water on your plans but it could save a lot of cold water later!
David
-
Many thanks Davy1,
Sounds like good advice, the more I hear and see online the more I appreciate how much of a "steep learning curve" this will be. OK, I feel confident in building a very detailed display model, and fairly confident in taking the lower technical challenge of making it a working surface runner - perhaps then even a dynamic diver with it trimmed low after confidence built in surface testing. One step at a time. The basic hull is not that pricey, nor will the cost of 'surface' running RC for two props and a rudder. Allow for adding dynamic diving planes later. ie: 4 channel, 40Mhz, etc
As you say, many of the wonderful videos etc I have seen are are for 'kits', although some of the scratch built ones are awesome!
Could I ask, do you think after this I should consider gaining experience on a pro-designed static diver package such as the Engel 212A? That way I could have my dream K first, then next a static diver with a proven pedigree that I could learn the 'art' with.
PS: It was always my intention to build the K as originally designed, no swan bows, and with all 3 guns plus superstructure mounted torpeo tubes as photos posted by 'subculture' and 'allnightin'.
-
With your experience, I dont think you willl have to much trouble building a working and diving submarine. Something like an Engel 212 I fear will be a rather simple, not too taxing affair (the Engel Lafayette is a little more of a challange and involves working with a GRP hull. If your keen on the engel dive system have a look at my Trafalgar thread (Its essentially a Lafayette internals but with two piston tanks and enclosed with a tube rather than making the entire hull waterproof like Engel)
http://www.modelboatmayhem.co.uk/forum/index.php?topic=14332.0
-
Sad there seems nothing 'off the shelf' to fit a 53 inch hull with only approx 4 inches i/dia and just over 3 inches i/height including keel.
There is the Merriman/Caswell sub driver/wtc built which is designed for the Revell Gato class boat.
http://www.caswellplating.com/models/sub-drivers.html
This has a 2.5" lexan cylinder, twin screw output and a large volume ballast tank which should be adequate to get you a scale waterline if you keep the upper works as thin as possible.
It's a gas/snort system, so no piston tank I'm afraid. Most of the dive modules/wtc's made by suppliers here in the UK are designed for larger boats, or those with broader beams.
In regards to losing your boat.- sail in clear and/or wadeable waters. Swimming pools are perfect, London and Hertfordshire based Dive-in events give you access to such facilities. There is also Black Park Model Boat Club which is just down the road for you, and they have a lot of model submariners in their ranks- the lake is spring fed, so the water remains very clear, although it is deep. A local scuba club help recover models which fail to emerge for a modest fee!
-
Subculture (Andy) is being a little modest. He is the one who runs the "Dive-Ins."
-
I thought Bob might have picked that up from my forum signature.
I've made it a little more obvious, so you can't fail to notice it now. :-))
-
I thought Bob might have picked that up from my forum signature.
I've made it a little more obvious, so you can't fail to notice it now. :-))
Yes thank you, I had already browsed this site with interest. I have just been down to Black Park Lake (it is big, and looks deep). No one there, so try again Sunday. I have got latest "Model Boats" mag (nice K boat in it!).
The Merriman/Caswell 2.5" diameter sub-driver system looks interesting, but even if I ship it from the States getting gas cartridges here might be difficult? A lot of valves to control. How long does the gas last, and when it runs out ... I will have to look up 'snort' systems. I have emailed them questions.
Doing some basic 'sanity' tests using a 2L coke bottle with a couple of lengths of tube it appears that once the neutral/zero buoyancy point is exceeded the bottle sinks to the bottom rapidly. Getting it to stay a few inches under looks tricky to trim for.
Hopefully on my next visit to Black Park I will meet some submariners O0
-
Might be worthwhile getting in contact with the club that runs there. Here is a link to their website-
http://www.blackparkmodelboatclub.org.uk/
The snort system is very simple. To submerge a small valve located at the top of the tank is opened by a servo. The bottom of the ballast tank is vented so the water flows in freely, and down you go. To surface a small diaphragm pump blows air via a snorkel into the main ballast tank. This does mean your boat needs to be trimmed slightly positively buoyant, or you will have to drive your boat under power until the snorkel mast broaches the surface in order to blow your tank. This particular system was difficult to implement, at least in small boats until a few years ago. The miniature diaphragm based pumps were difficult to find, and/or expensive. This is no longer the case.
If you like to run negatively buoyant and assuming you're unable, or unwilling to drive the boat to the surface, then the on-board gas system can be used as a back-up. An on-board reservoir (which is constructed from copper fittings) is filled using an external aerosol can (e.g. airbrush propellant) via a schrader valve .The amount of submerge/surface cycles varies, but generally you will get about eight or more. What happens if you lose count? The boat stays on the bottom, and this is one of the weaknesses of the gas system.
-
Do bear in mind that the 2.5" cylinder may not give you a scale waterline- it should get close. Not sure how much that matters or not.
-
Thanks. I have emailed Black Park Model Boat Club. Using a airbrush propellant aerosol can via a schrader valve sounds good, but getting it back to snorkel depth before you can blow the tank no so. Can't you just vent into the water via the valve if needed as internal air pressure will be much higher.
I was intending, through extreme caution, to build to near-scale waterline depth, with maximum ballast keeping just the conning tower above water. That way I can dynamic-dive the last bit whilst retaining some buoyancy in case all else fails. Seems more controlable after my weighted coke bottle test.
I guess so much depends on getting a tank system into the hull, then filling the bath.
-
Andy's advice to join a club is very good.
Also don't worry too much about water clarity/swimming pools etc. A lot of us now use an on-board Pinger which means that, in combination with a hydrophone, you may lose your sub but you do get it back. Unlike R/C planes, helicopters etc!
I'm still wondering how to ease the entry into model submarines for you. You have chosen a difficult subject (size, complexity etc.) - K's are rare models for that reason. To counter this you are very keen on building one and you are a very experienced modeller.
I think that the route that you've identified - surface runner - maybe dynamic diver - then ballast tank will work for you.
And make her fast - therefore very impressive as a surface runner - 24 knots on the surface remember!
Hope to see you at one of the events which the AMS attends.(i.e not Dive-Ins) http://associationofmodelsubmariners.com/
-
AMS members do attend the Dive-ins, alongside Sub Committee, BMSA and those who aren't affiliated to any organisation.
-
You might very well think that; I couldn't possibly comment. ...
-
It's not a thought David, it's a fact.
-
"You have chosen a difficult subject (size, complexity etc.)" - Yes, silly I know, but somehow the thought of a "build in a weekend" does not have quite the same appeal. I am still crazy enough to hanker after retractable funnels too :}
And make her fast - therefore very impressive as a surface runner - 24 knots on the surface remember! -
At 1/72 scale is that 1/3 mph ? But I know what you mean, bow wash (LOL)
Hope to see you at one of the events -
I would be honoured to meet any experienced submariner at any event, whether pool lake or whatever organisation. I aim to join the Black Park Club, but please note it could be a while until anyone sees me at the helm of a model steam sub. Lots to do, but at least I feel am underway. Thanks for all your input.
-
You take the square of the scale and divide that by the full size speed to get scale speed-
For example the square of 72 is 8.5. Therefore 24 (knots) divided by 8.5= 2.8 knots for your K-class
Not ultra quick, but not a dribbling along either. To get a realistic bow wake (for photographs etc.) you will need to increase this speed further.
-
Using a airbrush propellant aerosol can via a schrader valve sounds good, but getting it back to snorkel depth before you can blow the tank no so. Can't you just vent into the water via the valve if needed as internal air pressure will be much higher.
Yes thats the way it works, you can blow ballast with the stored air brush propellent at any depth. If you want to save on proplent and use the snorkle instead, but you need to be at perscope depth (snorkle out of the water). Of course if your deeper you can give a short burst of propel to empty just a small fraction of the ballast tank that will take you back to periscope depth- where you can continue to blow the tank with the snorkle.
-
Spot on bobk!
See you soon,
David Forrest
-
Of course if your deeper you can give a short burst of propel to empty just a small fraction of the ballast tank that will take you back to periscope depth- where you can continue to blow the tank with the snorkle.
Yes, that's pretty much right. You're going to trim ballast your boat so the ballast tank is full of water and the periscope is just out of the water.
If you 'stop engines' then the boat will surface to periscope depth without any help from the gas reserve. Only if the boat goes so deep that it become negatively buoyant and starts to sink, will you need the gas, and loss of signal (switch the radio off) will surface the boat from virtually any depth.
Normally, the boat will dive once the ballast tank is blown, and for deeper dives, the dive planes and forward motion will push it deeper. I guess you'd call that 'dynamic diving'.
-
I am now underway, starting with joining Black Park Model Boat Club today. O0
http://www.blackparkmodelboatclub.org.uk/ Nice facilities, plenty of space, friendly welcome. Very clear water.
Photo of Alan Rix and his ThunderTiger Netune at BPMBC:
(http://s1.postimage.org/1if282vus/BPMBC_b.jpg) (http://postimage.org/image/1if282vus/)
Thank you to Mike Caswell of Caswell Plating for this link to plans & photos of the K class subs:
http://support.caswellplating.com/index.php?/Knowledgebase/List/Index/40/submarine-plans
Next step, work on the hull . . .
-
Doing some basic 'sanity' tests using a 2L coke bottle with a couple of lengths of tube it appears that once the neutral/zero buoyancy point is exceeded the bottle sinks to the bottom rapidly. Getting it to stay a few inches under looks tricky to trim for.
Hopefully on my next visit to Black Park I will meet some submariners O0
Finding the neutral point is the hard part, and making sure its level. judious positioning of ballast and foam is the key.
-
Just to let you know I haven't lost steam on this project, just awaiting the K class hull to arrive from Deans Marine, and collecting beer cans. I need to simulate the Caswell sub-driver to confirm it will fit in the hull before ordering one from the States. A cylinder of 2.5" dia and 30" long. Turns out I have found an excellent real ale simulation, exactly 2.5" diameter, so, I am enjoying the sunshine by my Koi pond carefully transferring ballast from the cans until I get the desired thirty inches total length.
Can't rush it you know. With all ballast transferred I will then glue them into a card tube to effect the simulation. I now have a number of cans of different length, but the same diameter. Very technical approach {-) Photo to follow in due course.
I just wonder how many build projects start off requiring a precise consumption of ale ?
-
Oh lots and lots, it's remembering the master plan the next day which is the tricky part!
-
Attached are photos of my dimensional simulation of the Caswell sub-driver unit, 2.5" diameter and 30" long, made from empty beer cans.
When the hull arrived I thought this looks a lot larger than I had visualised, but fitting the simulation model it was a very close fit. Not too much space left for fitting frames, lead ballast, or running a rod through to the front diving planes.
I also need to make up a waterproof gear set to drive two props from a single motor. Ideally I would have liked separate motors. Any ideas?
(http://s2.postimage.org/8x4s3s10/K_Ballast_simulation_1.jpg) (http://postimage.org/image/8x4s3s10/)
(http://s2.postimage.org/8x836h0k/K_Ballast_simulation_2.jpg) (http://postimage.org/image/8x836h0k/)
(http://s2.postimage.org/8xbe9604/Caswell_Sub_Driver.jpg) (http://postimage.org/image/8xbe9604/)
This is going to be a real challenge, even getting the upper hull to fit snugly yet be readily removable for access will be interesting. %%
-
PS: You may have to double-click on the above images to see the whole image
-
Why not get the version with 2 motors (the one for the Gato- also 2.5")?
-
Yes what Mike said.
What you now need to do is remove a section that is equal in volume to the 2.5" subdrivers ballast tank and see what happens to the waterline when you dip it in the bath...erm test tank. Don't forget to take into the account the future superstructure, and allow yourself 10-15% extra for fudge factor.
I'm sure that if required, a special sub driver with a larger tank (if required) could be built, so there is some flexibility.
-
Many thanks Subculture & MikeW. I have since spoken with Mike Caswell in N.Y. He was so helpful. Some on the online pics are a bit small to appreciate, and also the latest twin-motor Gato sub-driver is three inches shorter, which should making mounting easier as it was the ends that got tight for space in the hull. Also, should give more flexibility for fore and aft positioning.
It turns out the Gato is only one inch difference in length, and is also fairly slender.
Next step will be ordering the sub-driver, then making up internal frames. Getting the balance point between centres of gravity & buoyancy should be interesting. I guess this will require a mock-up in water (yes, bath tub!) simulating weights for internals and superstructure. Should I get the actual speed controllers, receiver & batteries etc, or start off with with using equivalent sized weights?
Dumb question: What is 'blue foam'? I understand I need this to get buoyancy trim right.
-
It will be worth you have a surf around the Caswell website for the Cabal reports, particularly the one related to the alpha submarine. There are som e clear details on how to work out the best place to locate the sub driver
-
Blue foam is just expanded polystyrene, tinted blue. Also comes in pink and white. Bear in mind this foam is denser than the expanded polystyrene foam your average new TV set comes packed in.
In the States, they use it a lot for home insulation, so it's easy to get. In this country we tend to use polyurethane foam which is partly filled with ground glass, this tends to be yellow in colour. You can use this for buoyancy, and then glass over it to make it a bit neater. The other option is the expanding polyurethane foam you can buy in a tin, although that can get very messy very quickly.
If you want high density polystryrene foam in a smallish quantity, EMA model supplies sell it. http://www.ema-models.co.uk/index.php/materials/foam-polystyrene/expanded-polystyrene-sheet.html
One more thing- don't try using polyester resin with polystyrene foam- it melts it. Polyurethane is fine, you can glass straight over that.
-
I've just been taking a look at the Caswell Subdriver and although it looks excellent for a plastic kit conversion, I do wonder if it the best thing for your K class project.
(If you have just sent off your order please ignore this message!)
Even with 2 x 385 motors installed it is going to be a rather slow K class and $450 is also an expensive learning curve.
I wonder if you wouldn't be better off operating it first as a surface runner and doing some experimentation with the drive motors, props etc. (Basically squeezing them (it is a narrow hull) into a stern WTC.)
You will then get the most important thing about the model submarine right fairly painlessly - a fast destroyer with some diving ability.
Hope you don't mind me saying this but you did ask for advice.
David
-
3 mph on the surface, and about 1mph dived scale speed.
You really will need a shoe horn to get bigger than speed 400 can motors in though.
-
Appreciate your advice David. No, I have not sent off the order yet. Waiting for quote + shipping.
My thought was that by using a ready built driver unit it might save me numerous iterations of ripping stuff out and trying something else. A vast number of multiple unknowns here. The GRP hull is quite thin walled, and the video on the Gato page appears a fair speed. I want it to look realistic, but I understand power is needed to drive it under if not trimmed to decks-awash. That alone will be a corker to achieve I expect. :D
Designing and building a three-chamber WTC with all the glands for controls and shafts etc may be a bridge too far.
Cost is high, but that would be well worth it if it achieves the objective with less back-to-drawing-board 'sinkings'.
Subculture: With a 2.5" outside diameter WTC maximum motor size is hard to achieve, I agree. I could cheat and use a single C/L prop but that would spoil the realism.
Without all your help this project would have been vastly more difficult.
-
Its the wetted surface area that will determine the power needed to move the boat once its under so there should be little differance in the performance between the Gato and the K if they are similar sizes. If you decide to get the Subdiver, and for some reason find it underpowered, you could try swapping the motors with some 400 sized inrunners which should be a straight swap.
-
Doesn't your Trafalgar class use a geared speed 480, Ramesh?
-
Smaller than that, its a single geared 385 motor. Its the same drive system Sheerline supply with thier 1/64 Trafalgar kits.
-
Ah right. Well there you go Bob. One 385 motor is sufficient to propel a 1/64th scale Trafalgar class at reasonable speeds. Two in a 1/72nd K-class a boat of considerably smaller cross section, should cut the mustard. :-))
-
Ah right. Well there you go Bob. One 385 motor is sufficient to propel a 1/64th scale Trafalgar class at reasonable speeds. Two in a 1/72nd K-class a boat of considerably smaller cross section, should cut the mustard. :-))
Wow! That could turn it into a torpedo tube launched Harpoon cruise missile ! Do bow planes work as aerofoils in catamaran mode I wonder %%
Would certainly generate some bow wash.
I am definitely leaning towards adapting the Caswell system. They even do set of M1 fittings as a kit, rudder, bow planes etc, at same scale. Near enough identical to the K boats. Westbourne do 3 blade brass propellers of almost exact size required (must check photos to see if they are 'c/w or ac/w handed').
I need to figure out what is the best 6 channel 40MHz TX/RX system to use, without further breaking the bank. Ideally one that could also run a twin-prop WW1 destroyer of similar size I have just acquired on E-Bay.
-
Don't forget these are only 25mm diameter props, they wont need much to make them spin
I just took delivery of my M Class from Caswell, complete with the fittings, will try and post photo later.
At the same time i took delivery of one of the WTC for the Revell type VII (which i have half built), its a very very long shot, but i'm going to dunk the upper hull and sail in a tank to find its displacement, then see how much the ballast tank holds
-
I recommend prop shop for props, Bob. Not only are they very nice lost wax cast, so all one piece and with nice defined blade profiles, but they're also well documented.
I'm not sure if the Gato SD uses direct drive motors or geared- Dave Merriman tends to use both approaches depending on the application. If they are direct drive, go for a moderate propeller pitch, no more than 1.2x diameter, perhaps less. If you have a word with Simon at Prop Shop, he'll also advise on the best prop pitch for your application.
Andy
-
Whilst my K Class is under construction I had my first RC outing in almost 40 years, at Black Park Lake today.
See new topic http://www.modelboatmayhem.co.uk/forum/index.php?topic=29971.0 (http://www.modelboatmayhem.co.uk/forum/index.php?topic=29971.0) for photos.
An R Class destroyer of similar WW1 vintage, and almost same model length.
At least I have something to sail whilst the K is on the slips :-)
-
found a nice photo of members model K4 on edinburgh MBC website
Geoff
http://www.edinburghmodelboatclub.org.uk/members_models/03.jpg
-
Thank you Geoff. Very nice picture. Beautiful model.
Bob
-
Quick update:
I have now bitten the bullet and ordered the Caswell sub-driver. This includes motors valves and servos etc, plus M Class rudder and diving planes.
After much research nothing else will physically fit (2.5 inch diameter max) and I don't have access to a lathe etc to start 'inventing' my own WTC.
I have been given to understand that there may be only two other working K's seen at events around Britain, both in the north, so this could be something more special than I had anticipated when I took on this self-challenge. {:-{
In the mean time I am working on my HMS Skirmisher, rebuilding the internals and electrics, and bringing it back up to spec. Missing boats, davits, etc. This will also be fun, and give me something to sail on nice days whilst the K is in the prototype dock.
I intend going up to St Albans for the Dive Into Summer event on June 12th. I hope to learn a lot there
-
Ah top man.
Not only will the k-class be unusual, so will the Caswell/Merriman Subdriver. Most submariners over here tend to go for Sheerline, OTW, Engel or a DIY approach. I've seen pictures of one or two modellers up North with a Sub Driver in, but never down here.
-
I am more than excited ! My sub-driver package has arrived from the States. It really does look very well made, and fits the hull nicely.
Wow, there is a LOT of electronics in this, and at 2.5" inside diameter it will require very careful building. As you can see I did go the whole hog, rather than get enough just to get it going then try to add extras (which I will probably need anyway) later. O0
(http://s3.postimage.org/1z7o9ilvo/subdriver_kit_1.jpg) (http://postimage.org/image/1z7o9ilvo/) (click to enlarge)
Pictured above is the Caswell/Merriman SD25G Subdriver with installed twin motors, gas system, servo frames, snort valve etc.
Supplied separately are 6 micro servers, snort pump, rudder and diving planes from M Class model (identical to K's), pump controller PCB, self leveller module, drive couplers and linkages etc.
The primary dive system is the snort valve, which I intend plumbing into the tall forward radio mast. The gas system is to blow the ballast when below snort depth, which hopefully will allow many snort-depth dives without expending compressed gas. Gas used is from a regular airbrush aerosol can through a Schroeder valve at the top of the WTC.
I also took the opportunity to buy the WFly FT06-C 40Mhz 6 channel radio control, which at US$89 (£55) works out to a fraction of the cost of a Robbe F14 equivalent.
All-up that lot dented my Card to just over five hundred including shipping, but looking looking at many of the kits I've seen with built in sub driver I believe this represents excellent value, plus I could have paid well over 200 just for the radio control.
I intend having huge fun with this build, which will be over a long design & test period. I am already working out how I am going to retract the funnels before diving. Tee hee ! :}
-
Looks good. I'd say your first job, once you open all the packets, is to make a set of saddles for the subdriver to sit in. Retracting funnels shouldn't be tto hard- they swung in an arc I believe. Couple of miniature servos should do the trick, with a servo speed controller to slug the action a bit.
-
Good advice, thank you. I intend getting a Profile Template first so I can accurately replicate internal bulkhead profiles. I will leave plenty of fore and aft latitude for balance adjustment. One major problem is that the set came with effectively no instructions or photos, so figuring out where the 6 servos etc get mounted, actuating rods, how they seal through the WTC etc, could be sheer guesswork. Hopefully I may see a similar subdriver at the St Albans Dive-In so I can take photos and notes !
It appears that after building the WTC unit I should test that as a stand-alone unit. I found this video of a single motor version on YouTube . . .
http://www.youtube.com/watch?v=UNVHt5r567Y&feature=related (http://www.youtube.com/watch?v=UNVHt5r567Y&feature=related)
Please bear in mind that this is a total first for me %%
Any and all advice greatly appreciated !
Funnels:
On the original boats the funnels retracted through 180', with circular watertight hatches closing, also by 180'. (See diagram)
(http://s1.postimage.org/1e42czyx0/k_funnels_diagram.jpg) (http://postimage.org/image/1e42czyx0/)
(http://s1.postimage.org/1e48z5cw4/K_Funnels_1.jpg) (http://postimage.org/image/1e48z5cw4/)
With both funnels requiring 180 degrees in opposite directions, some kind of geared or compound linkage may be required to translate a 90 degree servo arm movement. As I said, an interesting problem.
-
Servos can operate over 180 degrees, but you need a servo extender to increase the throw, as RC receivers only operate over 1ms range which gives you the 90 degree throw.
Or you can apply gearing, but that will mean you need to slow the servo down even more. BTW, I find digital servos are much smoother when slowed down than analogue models- I think the higher pulse rate helps there.
With regards to instructions for your Sub driver, don't forget there is a dedicated forum for all things Merriman/Caswell- http://forum.sub-driver.com/index.php
You can talk to the man himself there, post some details up of what you're building, I know this will interest Dave. I'm also sure there are specific instructions for your Sub Driver- David is good with that sort of thing.
I use a profile gauge, and also soft solder for lofting lines for templates. Then I use old cereal packets to make templates from before committing to expensive material.
Andy
-
Andy, you are a real Star !
I have registered on the sub-driver forum, posting the kit photo above and asking for assembly instruction help.
In the mean time I will get a profile template for the mounting bulkheads. Good idea about using card to check fit first.
Thanks too for servo info. This will need my best Bagpuss thinking hat, but that's half the fun of building a concept instead of just a kit.
-
Thanks again Andy. I now have very detailed build instructions in PDF format, plus links to some extremely useful build videos.
For anyone interested in using a Caswell dive system I hope they will not mind me giving links to their published information.
Sub driver instructions:
http://support.caswellplating.com/index.php?/Knowledgebase/List/Index/35/sub-driver-instructions (http://support.caswellplating.com/index.php?/Knowledgebase/List/Index/35/sub-driver-instructions)
Very useful videos
http://youtu.be/_IgZ_M5t2l0 (http://youtu.be/_IgZ_M5t2l0)
http://youtu.be/-qo-Hs3Bl0I (http://youtu.be/-qo-Hs3Bl0I)
http://youtu.be/wSqcUBQy1ac (http://youtu.be/wSqcUBQy1ac)
http://youtu.be/lifC6S4sbuE (http://youtu.be/lifC6S4sbuE)
http://youtu.be/L5ayOY4mb1M (http://youtu.be/L5ayOY4mb1M)
http://youtu.be/lifC6S4sbuE (http://youtu.be/lifC6S4sbuE)
-
A pause in posting whilst I did a lot more research. I now understand much more on how the WTC goes together thanks to Dave Merriman. Hopefully I now have enough info to work out the technical interfaces between the WTC assembly and the hull, enough to get underway. The tube is a very close fit in the slim hull.
All electrics bar the battery is in the rear 'dry' compartment. Therefore the retracting funnels and retracting front dive planes should be operated together from the same servo in the rear of the WTC.
Working out the linkages for the funnels capturing still shots from a video clip . . .
(http://i1143.photobucket.com/albums/n626/bobkiralfy/K%20Class/funnelsequence.jpg)
The object is to retract the funnels and extend the dive planes from their slots in the hull via a dedicated Rx channel prior to trimming down for diving.
On this boat building the hull togther with building the WTC appears essential as otherwise I would end up cutting a lot of holes then have to fill some in and cut them again in slightly different positions as the WTC cannot be moved.
-
K9 Back On The Slipway:
Main slipway cleared following destroyer completion, the dockyard is now set up for the construction of my K9 to recommence. The submarine went on temporary hold late October whilst I pondered some basic sub-specific technical problems, and gained more model making experience building a surface warship.
(http://i1143.photobucket.com/albums/n626/bobkiralfy/K%20Class/kbuild1.jpg)
Here are the main design problems I am working on. Sorry, it’s a bit long.
WTC Positioning:
The WTC is a good fit in the hull section, but does have a limited fore and aft positioning ability. I know I have to get the balance point for centre of gravity and centre of flotation fairly exact otherwise it will submerge bow or stern first. I can build in supporting rib frames so as to allow fore and aft movement, but cannot connect up shafts or control linkages until I have got that right. I assume at this point I aim to get the framed-hull neutral ‘tip’ buoyancy and concentrate on the WTC ‘balance’ first. This appears to require building and commissioning the WTC first. Choice and weight of battery appears most critical.
If I start with a temporary dynamic diving solution then by the time I get that far into things there will be far too much to rip out and rebuild for static conversion.
Internal Framework
I need a series of frame ribs to strengthen the hull, “U” slotted to mount the WTC, and also securely locate the upper hull. Matching inverted “U” frames in the top hull, and strengthening beams along the length of both. The ideal being locating lugs at the rear, along the joins, and a single thumbscrew fixing at the front (maybe a deck gun?). I could use either 3 mm ply or 3mm styrene, neutral buoyancy being a factor in choice of material.
Control Linkages:
Unlike a Neptune or Engel ‘front end fit’ system, once the WTC is built in it cannot easily be removed without significant disassembly. Control linkages will run in tubes through the rib frames, especially to the bow as all servos are in the rear compartment. Bow hydroplanes need to turn and retract, plus control rod to geared funnels retraction. With the WTC so time consuming to get out, especially at a lakeside, ideally I could do with a means of turning on power and charging the battery that avoids disssassbly.
ie: Magnetic power switch, or stainless stud terminals with an external swivel “U” link. An extra stud for neutral, and I could charge battery using croc clips.
Finally:
Static Dive System
The Caswell WTC comes with a gas bottle system, plus a snort system that I intended using the radio masts as air intakes for. However, I understand the gas capacity only allows for 2 to 3 surfaces, and if I slip below snort tube depth the snort will not work. Should I opt for a water-pumped bag system instead?
Am I thinking on the right lines here ?
-
WTC positioning- the c.g on this boat is bang central on this boat, so mount the cylinder so that the centre of the ballast tank lnes up with that, don't worry about other equipment at this stage, when it's all in, you will use lead to balance the boat at the centre of the tank, and dial in the correct c.g.
You will then adjust the centre of buoyancy using foam or floatation cylinders (depending on preference).
For strengthening ribs I would use plastic or better still fibreglass sheet- much stronger. I would not use wood at all, and don't worry about the density.
Design the boat so that items are relatively easy to disassemble and remove. The whole idea of a cylinder system is that it's easy to hook in and out of a boat
Please don't charge batteries in a sealed container, it's not safe.
The concept of the snort/gas ballast system you have, is to only use the gas in an emergency situation. A water pump system won't fit in the confines of that cylinder.
-
Many thanks Subculture: As I'm sure will be obvious to all - this side of model boating is all new to me but I am determined to succeed, especially after being inspired at the St Albans Dive In last year !
WTC positioning at exact centre. That means I can get started on sheet fibreglass bulkheads.
Fair comment on not charging battery in situ, but does mean I have to figure a way of disassembling all the WTC connections to get it out. Pity the narrowing hull width at the front hydroplanes precludes a front exit using magnetic couplings at rear. I will have to have more thoughts on that.
On the ballast system, my inexperience is bound to encounter ‘emergency situations’ frequently at first. OK, if I need to blow gas (even once) then bring it in to recharge the air tank. Hopefully, when I get the ‘balance’ and trim right, 140 mm radio masts should give a reasonable snort length. I might even make them much longer to start with.
Bob K
-
How high can you raise the WTC above the hull bottom?
-
How high can you raise the WTC above the hull bottom?
The WTC effectively rests on the inside of the hull bottom with only 3 mm clearance under the upper hull. There is a small void space within the keel but this ends about an inch past each end of the WTC. Might be able to route hydroplane rods through that if cranked. Alternatively there is quite a lot of space alongside the WTC, 20 mm at centre narrowing to 5 mm at WTC front end.
-
Can't you run the linkage for the front planes across the top of the cylinder?
-
Can't you run the linkage for the front planes across the top of the cylinder?
Sounds like a good idea, I can try that. Alongside cylinder top, so I can pull WTC upwards to extract
Photo of WTC front end in hull. A lot more space halfway along hull, but narrows fore & aft.
Cut edge is widest part of section profile. Modern subs tend to be more circular in section.
(http://i1143.photobucket.com/albums/n626/bobkiralfy/K%20Class/KhullWTC.jpg) (http://i1143.photobucket.com/albums/n626/bobkiralfy/K%20Class/frame113.jpg)
Bob K
-
I think I can see possibilities here ! Maybe if I attach the control rod tubes to the WTC, then I only have to disconnect at the front end.
(http://i1143.photobucket.com/albums/n626/bobkiralfy/K%20Class/controllinkages.jpg)
-
If you connect up with the magnetic connectors throughout, then removing the WTC from the hull should be a quick affair.
-
Eeeem. That’s rather sunk my design for retracting funnels using two sets of servo gears, brass tube rod and plates. This was intended to be mounted on top of the WTC to get a precise ball joint linkage, with the upper hull lowered in place over it. Now I shall have to look at a flexible Bowden cable to a sub frame inside the upper hull.
The motor shafts are 4.8mm dia with a pronounced D flat, which I have to devise a way of connecting to 2mm prop shafts via universal joints angled at about 5 degrees each, and add magnetic couplings. Will they take power?
With only a single day oogling inside peoples submarines I am now trawling Mayhem and Google to find photos or diagrams of control linkage set ups. Surely it should not require almost total disassembly at the waters edge, comparable to having to remove a cars engine and transmission just to turn the ignition or fill with petrol? One lost grub screw and its pack up and go home.
Bob K
-
The driveshafts are usually coupled using dog and bone couplings, not magnets.
Most submarines don't have much going on like retracting funnels, but watch the weight up top if you're using brass.
I would study the Revell Gato conversions, as the two boats share a lot of similarities- twin screw, forward and aft hydroplanes, single rudder and a high freeboard.
-
Magnets can be useful.
(http://s16.postimage.org/zabuvyhn5/DSCN0029.jpg) (http://postimage.org/image/zabuvyhn5/)
(http://s16.postimage.org/ddpbvl4gh/DSCN0033.jpg) (http://postimage.org/image/ddpbvl4gh/)
(http://s15.postimage.org/grq3j1gp3/DSCN0105.jpg) (http://postimage.org/image/grq3j1gp3/)
(http://s17.postimage.org/ultlzfs9n/DSCN0106.jpg) (http://postimage.org/image/ultlzfs9n/)
(http://s7.postimage.org/6vxa8877b/DSCN0114.jpg) (http://postimage.org/image/6vxa8877b/)
(http://s15.postimage.org/p2bwqvc93/DSCN0096.jpg) (http://postimage.org/image/p2bwqvc93/)
(http://s16.postimage.org/5z4lgy7yp/DSCN0003.jpg) (http://postimage.org/image/5z4lgy7yp/)
(http://s16.postimage.org/zfk7jdec1/DSCN0016.jpg) (http://postimage.org/image/zfk7jdec1/)
(http://s14.postimage.org/67gmjtt4t/DSCN0024.jpg) (http://postimage.org/image/67gmjtt4t/)
-
Wow Dave, those photos were really useful. Many thanks. :} :-))
I see the motor shaft uses a ball joint (readily disconnectable) so the magnetic couplers are just for the control rods. I like the way both 90' and 180' transitions are done in your pictures, and especially how the geared forward dive plane retraction is done. Burning question now is - can I order a fairly comprehensive selection of these through Caswell ? Please PM me if this is possible. I could link my funnel retract gearing through a rod inside the upper hull, using a right angled magnetric coupler.
I do have some ball joint couplers, and could drill these out to fit the motor shafts.
Thanks again !
-
Most submarines don't have much going on like retracting funnels, but watch the weight up top if you're using brass.
Thanks. I know hankering after working funnels maybe dumb at my level, but I can't resist it. Now, if I can get the boat to go up and down too . . .
-
Wow Dave, those photos were really useful. Many thanks. :} :-))
I see the motor shaft uses a ball joint (readily disconnectable) so the magnetic couplers are just for the control rods. I like the way both 90' and 180' transitions are done in your pictures, and especially how the geared forward dive plane retraction is done. Burning question now is - can I order a fairly comprehensive selection of these through Caswell ? Please PM me if this is possible. I could link my funnel retract gearing through a rod inside the upper hull, using a right angled magnetric coupler.
I do have some ball joint couplers, and could drill these out to fit the motor shafts.
Thanks again !
You're welcome.
Drop the practical funnel-closure-valve mechanism.
FIRST: get that boat working in the water! Don't load it down with gadgets and crap. Not till you have the boat running, and the 101 bugs you're going to encounter worked out, anyway. Only with the boat working well can you get fancy with the funnels and shiny stuff. Keep it simple, learn the boat.
Crawl, walk, then, and only then, run, damit! Practical funnels and the like is, 'running'. You are not ready.
I don't have time to e-mail and PM. My time is precious: I'll spout off in public. It saves me having to repeat myself. And you, don't you be shy about reviewing the FAQ's at this and other related forums. You'll find most of your questions have already been answered, decades ago. There's nothing new here other than the faces of those who come and go.
And don't post so much. Every minute staring at the monitor and banging on the key-board is a minute out of the shop! Get to work.
David
-
on ebay now
http://www.ebay.co.uk/itm/K-class-submarine-hull-swan-bow-revised-version-/260966238792?pt=UK_ToysGames_RadioControlled_JN&hash=item3cc2ccca48
-
Interesting. It is just the basic fibreglass hull, without superstructure rudder planes props etc. at £120 looks very similar to Dean's K hull at the same scale which is £86.81. Deans is based on the pre swan bow, as built.
http://www.deansmarine.co.uk/shop/product_info.php/cPath/26_33/products_id/2251 (http://www.deansmarine.co.uk/shop/product_info.php/cPath/26_33/products_id/2251)
-
Looks to me like the superstructure is present on the ebay special, plus a rudder and shafts if the photo is to be believed.
Would be nice if the seller showed some higher resolution pictures.
-
Quote from the topic...
SUPER STEAM SUBMARINE
1/72 SCALE "K" CLASS HULL WITH "SWAN" BOW
LENGTH: 55 INCH
MATERIAL: FIBERGLASS
ORDER TO MADE
USUALLY TAKES AROUND 7 TO 8 WORKING DAYS
IF YOU HAD ANY QUESTION DON'T HESITATE TO ASK :)
WE ARE HAPPY TO ANSWER YOUR QUESTION
# Above picture shows the hull with the superstructure on. ( It show how it look like when it finish built)
# Product does not include the superstructure or the rudder or the propeller.
# Product only contain one fiberglass hull
-
Hmmm, always read the small print. Don't like that sort of practice- showing a picture of what it can look like, not what you'll receive gets alarm bells ringing. Postage rates seem a bit stiff- thirty quid, I should co-co.
-
Not intending to upset anyone, but on Tuesday I was this close to scrapping the sub driver and completing the boat as a surface runner - with all the detail, including funnels.
I can build boats, and have a ring binder bulging with downloaded ‘instructions’ and FAQ’s on the SD25.
By getting an assembled sub driver I had naively thought I could install the electrics and commission it, that the main design process would begin in adapting it to the hull and the control linkages. After many months I established this is not the case. Submarine expertise appears assumed and info most often thins out at the end caps.
For me the WTC is still most of development and build work.
First area for rework is the motor compartment.
L.H. photo is from the PDF manuals, R.H. is as supplied.
(http://i1143.photobucket.com/albums/n626/bobkiralfy/K%20Class/Caswelldocs1a.jpg) (http://i1143.photobucket.com/albums/n626/bobkiralfy/K%20Class/AsSupplieda.jpg)
So different, the manual becomes what I have in my hands. It appears I have to cut the lugs off the 4 micro servos, sticking them in with double sided mounting pads, then make an extension tray to mount the Rx and snort pump.
From photos kindly posted recently I can see that the brass ‘U’ couplers supplied should be fitted direct onto the motor shafts, but to do so requires the help of someone with a lathe. I only expected to have to rework the prop shaft ends. One recent posted photo showed the plastic ‘dog bones’ cut down drilled and tapped to suit the shaft. Great idea. Thank you.
I only ‘found out’ about magnetic couplings last week, hence my concerns as to how I was going to get the WTC out. Unless I can source these I will buy some micro rare earth magnets and try my hand at resin casting.
This is going to be a long build, but I will get there.
Fitting the main tube on hull bulkheads is not a problem. Interlocking bulkheads on the hull top with locating lugs along the joins. Non technical, just model-making.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Today I hopped in the car and came home with an Engel Type 212A,
IMO essential to see understand and work with many design and operation aspects that are still not as clear as they ought to be by now.
Call it a development prototype for the K.
-
Dave has made some mods to the sub drivers since you purchased yours, and I think that includes resin castings to enable the servos to be mounted in with their lugs intact. Might be worth having a word with him to see if you can tune up your sub driver. He also does magnetic couplers (called kli-cons), but they look easy enough to DIY too.
Good choice on the 212.
-
Ineed, the design has matured a bit since your unit was produced. If you would address your specific questions about the current situation, your situation with the SD in hand, I'll address them in adiquate detail to get your through this.
I am are currently going through the entire SD line and are writing up-to-date instructions to accompany the product.
David
-
David. I would hugely appreciate that. Your photos were very helpful. Thank you.
The quality of parts, especially resin castings, are excellent, and I understand that continuous improvement can quickly outpace documentation. The PDF’s I had been pointed to are the Seaview implementation, and almost entirely just of the SD assembly.
This unit is ultra compact. If cutting the servo lugs off is what I should do, then OK. I was unsure.
What would really help me most at this point is a basic generic block wiring diagram showing which leads go to where, I only had wiring connection info with the ADF2 angle driver and snort pump. Are front and rear dive planes on separate servo’s or combined? Do planes work in the same direction or opposed? Motors rudder and planes are on the Tx sticks, but should gas bottle and snort be from sliders or on/off switches?
Is Rx wired from main battery (I assume 6V), or separate battery pack. Is there a recommended battery, weight being critical.
I got the recommended WFLY FT06-A, which was an amazing price for a 6 ch 40Mhz system, but I was not able to obtain the later required Sombra Labs TL-8 receiver as they don’t make a European 40Mhz version. I have just bought a Robbe/Futaba F14 six channel 40Mhz system to replace the WFLY which I hope will be suitable.
Do Caswell stock magnetic couplings? I have been unable so far to find any over here. If not I can make them.
-
David. I would hugely appreciate that. Your photos were very helpful. Thank you.
The quality of parts, especially resin castings, are excellent, and I understand that continuous improvement can quickly outpace documentation. The PDF’s I had been pointed to are the Seaview implementation, and almost entirely just of the SD assembly.
This unit is ultra compact. If cutting the servo lugs off is what I should do, then OK. I was unsure.
What would really help me most at this point is a basic generic block wiring diagram showing which leads go to where, I only had wiring connection info with the ADF2 angle driver and snort pump. Are front and rear dive planes on separate servo’s or combined? Do planes work in the same direction or opposed? Motors rudder and planes are on the Tx sticks, but should gas bottle and snort be from sliders or on/off switches?
Is Rx wired from main battery (I assume 6V), or separate battery pack. Is there a recommended battery, weight being critical.
I got the recommended WFLY FT06-A, which was an amazing price for a 6 ch 40Mhz system, but I was not able to obtain the later required Sombra Labs TL-8 receiver as they don’t make a European 40Mhz version. I have just bought a Robbe/Futaba F14 six channel 40Mhz system to replace the WFLY which I hope will be suitable.
Do Caswell stock magnetic couplings? I have been unable so far to find any over here. If not I can make them.
Bob,
I've provided below some shots that will help guide you as you install the devices on the foundations attached to your motor-bulkhead. Note that almost every item in the after dry-space is semi-permanently attached, in one way or another to the motor-bulkhead; when the motor bulkhead is installed/removed from the cylinder, the entire assembly moves as a unit. The only make up to the cylinder being the two power cables from the battery-switch harness, and the lead from the ballast sub-system servo -- other than those two items, all propulsion and control hardware is mounted to the motor-bulkhead.
The below block diagram illustrates for you how the leads between the various devices connect to one another. Note that the receiver is the nexus point for most of what is going on in the SD; it is through the receiver bus -- fed from the ESC's BEC -- that the required five-volts is distributed to the other devices that make up the system.
Never connect the stern planes and the bow planes on the same linkage. Those two sets of control surfaces do two different things: The bow planes contribute little angular moment to the submarine, but they do push the vehicle up and down -- they are used for depth control. If you're inclined to employ an ADF, that device is placed between the receiver and the bow plane servo.
The stern planes of a submarine contribute mostly a pitching moment to the vehicle (the phenomenon of 'Chinese planes' aside for this discussion), so they are employed to set/maintain/alter the boats pitch angle, the 'bubble'. Just as helicopters require some artificial stabilization and damping about the yaw axis, a submerged submarine needs autonomous control of the pitch angle. You stick the angle-keeping device (in our case, the angle-keeping leg of the consolidated ADF device) between the receiver and the stern plane servo.
Don't mix, mechanically or through the transmitter, the stern planes and bow planes.
Here's the assignment of stick/switch/knob transmitter controls to the functions aboard your model submarine:
ch-1 rudder (right stick, left/right motion)
ch-2 bow planes (right stick, up/down motion)
ch-3 throttle (left stick, up/down motion)
ch-4 gas ballast sub-system (left stick, left/right motion)
ch-5 low pressure blower/snort
ch-6 stern planes
(http://s15.postimage.org/jk8sd0n3r/033.jpg) (http://postimage.org/image/jk8sd0n3r/)
Here's the arrangement of the devices aboard a 2.5 SD. Once thing I would change: I would put the fuse between the battery and the input side of the ESC.
(http://s17.postimage.org/xrllz6tjf/002.jpg) (http://postimage.org/image/xrllz6tjf/)
You're biggest challenge is running the 1/16" brass pushrods through the motor bulkhead watertight seals. Here you get some appreciation on how creative you need to get when bending these things to make up to their respective servo bell-cranks without binding, or getting in the way of the centrally located receiver
(http://s16.postimage.org/54y803t35/006.jpg) (http://postimage.org/image/54y803t35/)
Just some of the tools I use when bending servo pushrods to shape.
(http://s7.postimage.org/mmuecn8ev/013.jpg) (http://postimage.org/image/mmuecn8ev/)
Note that the central area over the cast resin servo foundation is open, ready to accept the systems receiver.
(http://s18.postimage.org/cpoucgys5/014.jpg) (http://postimage.org/image/cpoucgys5/)
The Kli-Con magnetic couplers -- that interface between the SD pushrods, and the control surface pushrods -- shown here. Yes, they are stocked by Caswell Inc. Note the Dumas couplers (3/16" bore) attached to the two motor output shafts. The two 3/32" tubes atop receive external hoses that lead to the ballast tank and the induction intake up in the sail -- a portion of the LPB/snort ballast sub-system.
(http://s14.postimage.org/tuo2eqj8t/019.jpg) (http://postimage.org/image/tuo2eqj8t/)
While tweaking the bends in the pushrods to achieve minimum binding I made good use of a 'servo-setter' device. Or, you can hook up the receiver and battery, and twiddle the sticks from the transmitter as you work to reduce the drag between pushrods and watertight seal gland.
(http://s13.postimage.org/m5x72vmxv/008.jpg) (http://postimage.org/image/m5x72vmxv/)
I prefer to attach the servos with RTV adhesive/sealant. This holds them fast within the cast resin foundation, put will part if you need to yank the servos out of there.
(http://s16.postimage.org/ipozz88w1/010.jpg) (http://postimage.org/image/ipozz88w1/)
(http://s17.postimage.org/5ijxozdaj/105.jpg) (http://postimage.org/image/5ijxozdaj/)
Just some of the devices that attache to the motor-bulkhead foundations. Receiver, ADF (angle-keeper and fail-safe circuits on one board), and ESC. Not pictured is the LPB pump-motor and its attached MPC (motor pump controller), and Lipo-Guard (commands a blow before the Lithium-polymer batter voltage drops below the critical (destructive) level.
(http://s7.postimage.org/5q9wxyq8n/106.jpg) (http://postimage.org/image/5q9wxyq8n/)
Bottom aluminum sheet foundation. This is where the LPB and its attached MPC are mounted with servo tape.
(http://s10.postimage.org/cbkkij4gl/004.jpg) (http://postimage.org/image/cbkkij4gl/)
An outfitted 2.5 SD. The ADF is servo-taped to the side of a servo. The Lipo-Guard is so mounted on the other side. Note that the receiver fits between the servos, atop the cast resin servo foundation. The ESC attaches to the forward face of the device bulkhead.
(http://s17.postimage.org/ajrbqckqz/005.jpg) (http://postimage.org/image/ajrbqckqz/)
-
I got the recommended WFLY FT06-A, which was an amazing price for a 6 ch 40Mhz system, but I was not able to obtain the later required Sombra Labs TL-8 receiver as they don’t make a European 40Mhz version. I have just bought a Robbe/Futaba F14 six channel 40Mhz system to replace the WFLY which I hope will be suitable.
You didn't need to purchase a complete new set, Bob. The WFLY 40mhz TX would work with any 40mhz receiver- the Sombra labs is popular in the U.S because it has a slew of nice features, but you can find the same range of features in 40mhz from other brands.
A cheap receiver is the Corona brand, more expensive receivers from Schulze and Multiplex are excellent performers. You do need a small receiver for your boat- just not enough space for the larger types.
-
Wow Dave, that’s what I call some mega design improvements, new layout, and incredibly is even more compact.
The connection diagram was especially useful. I now understand how the electrics are set up. I have set your text and full size photos in my DTP and is printed at the front of my ring binder. Thank you. I will call Caswell Inc next week re Kli-Cons and battery etc.
I intend using the tall aft radio mast for the snort, making it extra tall to begin with.
Subculture: Ooops, I thought Rx and Tx units were manufacturer specific and had to be paired. Getting the F-14 showed my determination to get this build up and working.
If I had waited a day and seen the new Rx and ESC mounting positions . . . !
No, the F-14 Rx will not fit in there, but would fit the other side of the aluminium plate as in the older ‘Seaview’ photos I was going by. I will look up the other Rx types you mentioned for size and spec.
-
There can be some incompatibilities among one or two sets- some use negative shift PPM, others use positive shift. Most computer sets enable you to alter that, but the F14 or WFLY rig won't.
If you use something like a Schulze receiver, they work with either, but manufacturer specific receivers can sometimes be fussy.
I remember someone once telling me my Fleet TX wouldn't work with anything other than Fleet RX's, which was complete fiction.
The Corona, Schulze and Multiplex RX's are very compact. Multiplex and Corona tend to be synthesized, so no crystal needed.
-
Progress today ! A local engineering company machined the brass drive couplings for me, which now fit snugly on the motor shafts. I have shortened one end lug each on the four servos and fitted them to the resin frame.
More good news : - Four sets of Kli-Con magnetic couplers are on their way to me from Caswell Inc. Thank you Caswell !
Thank you Dave, your latest design info has made all the difference. With the old info I had, I hope you will understand and forgive me for getting confused.
I am now underway :} :-) :-))
Sourcing a suitable receiver that both works with the Robbe-Futaba F-14 and small enough to fit in the space is taking longer than expected. The Corona RP6D1 and Schulze Alpha-5.40w both might fit the bill, although the later seems hard to source in the UK. I will need a separate battery pack for this as the 3000 mAh litho polymers specified are 11.1V. The LiPo battery and LiPo Guard I will also have to source here as LiPo’s cannot be shipped overseas from the States.
-
The Schulze will have the edge on quality. The Corona is difficult to beat on value. I use Corona 2.4ghz kit, and it's great. I have one of their little 8-channel 40mhz dual conversion synthesized receivers too, but haven't tested it in a submarine yet. Works great in other models.
Why do you need a separate battery? You're using an ESC which has a built in BEC, that regulates the 11.1 volts down to 5 volts for the receiver and servos.
I get Lipos from Hobbyking shipped from China. I've been happy with the performance of them. 3000mAH will give you long sailing times.
-
Why do you need a separate battery? You're using an ESC which has a built in BEC, that regulates the 11.1 volts down to 5 volts for the receiver and servos.
I didn't know that, having previously used 6V lead acid & 6V NiCad batteries in surface warships. Using an Mtroniks Sub 10 Esc on the K.
I am a bit nervous of Lipo's, having seen one go up !
-
I'd advise fitting a fuse. Some people are against fuses, because they consider them to be a potential route of failure. Well I work in an electrical based discipline, and everything is fused, and we don't get nuisance blowing- correctly rated fuses only blow when something is seriously wrong, which is what you want. I'd sooner have a boat dead in the water than an on-board electrical fire any day. After all a 3S 3A lipo pack is easily capable of delivering best part of a kilowatt or more.
Some electronic boards e.g. a lot of the engel piston tank controllers, don't need a fuse fitting, as they build a fuse into the PCB board in the form of a smaller copper track. AFAIK Engel are the only company that do this however.
I've been using lithium batteries for about ten years now, and they're without a doubt my favourite battery technology. What I will say is that I think it's important to balance charge the packs.
-
The K has been on hold for a few weeks waiting for various parts. The special Lipo-Guard from Caswell was held up in UK Customs for three weeks, but has now arrived.
The LiPo battery I could not source from Caswell as they can't ship LiPo's overseas, so I purchased what I thought was a similar spec here. Unfortunately it is about 3/4 inch too long for the battery compartment. Another 'spare' to put into back stock. I will need to search again for a 3000mAh 3s (11.1V) but this time try a 25C spec as that should be more compact.
I managed to source a small Multiplex IPD Receiver, but even this is a bit too large for the small space between the servos and the inside of the clear tube. I might try taking it out of its case as a few mm may do the trick. Pity I can't use the WFLY 40Mhz receiver & Tx I bought with the original system. That fits nicely.
-
Why can't you use the WFLY system?
Hobbyking are good for lipos, they do a very wide range in different C ratings, and the prices are good. Don't over look other capacities either, for instance these 4000mAh packs are very short and stubby, unlike the 3000mAH packs which are long and slim.
http://hobbyking.com/hobbyking/store/__11612__Turnigy_4000mAh_3S_20C_Lipo_pack_Perfect_for_QRF400_.html
http://hobbyking.com/hobbyking/store/__8851__ZIPPY_Flightmax_3000mAh_3S1P_20C_.html
-
Why can't you use the WFLY system?
I was advised from the States not to use the WFLY Rx in this application. The Sombra-Labs SL-6 is their recommended Rx, but unfortunately these are not made in a UK compatible 40Mhz version. So, I ended up replacing the WFLY system with a Robbe Futaba F-14 6 ch, but have been trying to source a smaller Rx for it. I may end up using the WFLY system anyway, the Rx is very compact and it fits. Not sure what the preceived problem with it is.
I will check out those Lipo links you kindly gave, now I know more about what I am looking for. ie: Best 11.1V spec that will dimenionally fit in the battery compartment. Weight may be a factor, but I will have to fit one to find out.
-
Thanks for those links, especially the first one. I have now ordered the Turnigy 4000mAh 3S 20C Lipo pack. Amazingly compact, will definately fit inside the 2.5" OD tube, and a higher mAh rating then the one I have that is too big, plus cheaper. The other linked LioPo was a touch too long.
Prices in US$ put me off at first knowing the States do not allow air shipping of Litho's, but I believe this is from Hong Kong.
-
The Sombra Labs is better at rejecting interference, as it's dual conversion and features pulse conditioning. Multiplex offers similar features, and the Schulze receivers are very good, but single conversion and non-synthesized.
If the Wfly fits, try it, it may work just fine. It may also work with your F14 if they're both on the same frequency.
Yes the stuff comes from China. No problems with shipping, the battery should arrive within ten days or so.
-
Do to the tight packaging of other electronic devices within the after dry-space of that SubDriver, you'll find that the WFly receiver simply does not have the noise-rejection ability to cope with that very noisy environment. It'll work fine with a strong carrier, but the moment you turn off the transmitter (signal loss), the ambient electronic arcing and sparking going on in there will swamp the WFly receiver, and the servo will simply go insane! Very unlikely to get a valid fail-safe condition with all that going on.
Andy's suggestions are valid -- based on his high knowledge and experience base. Listen to the man.
David
(http://s17.postimage.org/r8xen4qt7/004.jpg) (http://postimage.org/image/r8xen4qt7/)
(http://s15.postimage.org/9keun0gyf/005.jpg) (http://postimage.org/image/9keun0gyf/)
(http://s9.postimage.org/5sy8zscmj/007.jpg) (http://postimage.org/image/5sy8zscmj/)
-
Thank you David. I have bought a small Multiplex IPD receiver, but it is still 1/8" too wide and 1/8" too thick to fit in the space. A pity Sombra Labs do not do a 40Mhz version for UK use. I will try to find a Schulze Rx in 40Mhz, which Andy had also suggested.
-
Removing the case and wrapping in heatshrink may give you the required clearance for your multiplex receiver.
The Sombra receiver is extremely compact for an 8-channel model, dimensions are listed as 37mm x 20mm x 12mm
Schulze receivers work extremely well, but are a little bigger, and looking at Dave's pictures I don't think you'll have enough room. The 8-channel Delta model is 53mm x 21,5mm x 13,5 mm
They do a smaller 5-channel model 37mm x 20,5mm x 9 mm, and that will definitely fit in the space provided.
The Schulze receivers are a bit tricky to get in 40mhz here in the UK, however Engel stock them , and you should receive your purchase within a a couple of days if you order from them. You can use standard Futaba crystals in Schulze receivers.
Another alternative you could consider. This Corona receiver is bargain basement, the resolution isn't as good as the Schulze or Sombra receiver (no big deal on subs), and I've heard from other sources that the range is not quite as good as more expensive brands. But it's synthesized, so no crystals needed and smaller than the Sombra, so it will definitely fit. I've used their 2.4ghz kit and have found that works extremely well. Price is difficult to beat.
http://www.hobbyking.com/hobbyking/store/__6440__Corona_Synthesized_Dual_Conv_Receiver_9Ch_40Mhz.html
-
Andy you are a Star ! :-))
I know there are times when you must think I seem to attract problems like a neodymium magnet.
OK. I have a 40Mhz Multiplex Micro-IPD Rx here, got it through Westbourne. My error in not checking dimensions first. Measures 55.3 x 30.3 x 16.2. Just tried it without the case, but it's still too tight even before heat-shrink. Good idea though.
For Reference the 8 channel Sombra Labs Rx is 37 x 20 x 12. I could maybe ‘squeeze’ in 50 x 26 x 12 max.
The Shulze Delta dimensions you quote would be too big, but the 5 channel would (37 x 21.5 x 9). Ideally, with 4 servos + gas ballast + snort I would have liked 6 channels minimum.
The Corona sounds interesting, especially as its synthesised (no Xtal), and 9 channel, plus connector pins are on the end like the Sombra. At 36.0 x 18.7 x 8.2 that would fit nicely. Thanks for the link !
I assume I could use that with either my WFLY Tx or my new Futaba F-14, both are 40 Mhz.
With David’s appreciated explanation of probable interference if using the WFLY Rx as it is in very close proximity to motors and ESC etc, might it be advisable to mount the Corona Rx well forward of the ESC instead to reduce possible interference? There is approx 85mm between the ESC and the gas switch on the next O-ringed bulkhead. Although I do love David’s new ultra-compact electrics layout.
-
Bob,
Sorry that the current installation geometry is giving you such a problem with receiver choice and placement. When I designed the system, I only had the Sombra receivers (the SL-6 and SL-8) in mind -- not bothering to think at all that Aroosh had not provided receivers compatible on the more common European bands. Damn!
Give the WFly receiver a shot, but my experience with those things has not been a happy one.
David
-
I didn't know neodymium magnets attract problems, iron filings yes, problems no.
It should be no problem with either of those radios, although I can't say for definate with the WFLY radio, as I don't have one of those. I have used this receiver with my FC16 and my trusty old Fleet Omega 7 and it worked perfectly with both. So your good to go with the F14.
It's best practice to keep the receiver as far away from the ESC and motors as is physically possible- easier said than done in subs though, especially the small ones.
I would set things up as shown, then start tinkering if things aren't behaving well.
-
Thank you both.
No complaints on buying the 40Mhz WFLY system, at only US$89 (£56), it was about the same price as a 2.4Ghz Planet T5 here. Just a pity about the Rx in this application, and that Sombra don't do a 40Mhz version.
I have ordered the Corona that Andy recommended, no point in taking addtional risks over a hap'th of tar, and will wire it up with lead lengths that can mount either in the standard position or flip over to mount close to the forward end of the compartment.
When (and I don't mean 'if') this all works nicely I am sure it will encourage others to go down the SD25 sub-driver route.
-
Could be a long delay. Last week I ordered a special LiPo battery and Corona receiver from HobbyKing in Hong Kong. A rapid series of confirming emails about payment received and items being packaged for dispatch. Today they send me a confirmation that the items have been dispatched, but . . .
"YOUR ORDER MAY TAKE UP TO 45 DAYS TO ARRIVE.". !!!!
Whilst I accept the possibility of being held for up to three weeks in Customs, like the US LiPo-Guard recently, I sincerely hope that six and a half weeks max delivery quoted is not typical. I was hoping for just another week to restart building.
-
I've ordered from them lots of time. Never had to wait more than fortnight for the goods to show at this end provided the items were in stock when you ordered them. The fact that they've said your order is dispatched is a good sign.
-
Fingers crossed Andy O0 This is in R&D, but I'm keen to get going.
-
Some progress on this long build saga !
On 10 April I ordered a Corona RP8D1 receiver plus a Turnigy 4000 mAh Lipo battery from Hobbyking in Hong Kong, only to be emailed on dispatch to allow 45 days for delivery. Well, they finally arrived, with a time span more indicative of ocean freight.
Good news is that the Corona Receiver just fits into the very tight space between the servos, motors and ESC. This will be my fifth receiver bought for this build, and the final option remaining to get an Rx that would meet the high spec and noise resistance required. Previous purchases have been the original WFLY, two Robbe/Futaba’s, and a Multiplex Micro-IPD.
The battery is proving to be more challenging. The Turnigy ordered, based on dimensions quoted online, turned out to be too tight a fit for the sub-driver tube. I had allowed for my estimate of the slight corner radius based on other batteries I have, but it came almost square cornered. This LiPo now joins the one I bought from Westbourne that appeared to match the US spec but was far too large. My ‘spares’ shelf is growing. Turnigy single-in-line LiPo’s tend to be too long unless reducing to very small mAh.
Today a club member recommended the Component Shop, saying how good their customer service was when asking unusual questions. Their advice was spot on. A five minute call describing the spec I was seeking, and that it had to fit inside a 60 mm ID tube in a space 130 mm long. He even measured the diagonal for me. I now have a 2800 mAh S1 25C that will fit the space ordered due to arrive within 48 hours.
Best part was they even asked what type of connector I wanted, and it is coming fitted with that.
-
Silly Question?
Going "LiPo" still causes me concerns, especialy for underwater use. Looking online I can get standard 9.6V NiMh packs of almost identical mAh capacity that are almost identical in size to this 11.1V Lipo. In this case why use a LiPo at all? An NiMh can be charged in situ, operated with a magnetic switch obviating lake-side dismantling, and is unlikely to catch fire if it gets wet or upset.
I have a 2800 mAh NiMh running twin motors in my destroyer that happily sails for hours on a charge
-
Sorry to hear the battery was too big. Always worthwhile making a simple cardboard template of the pack and double checking to see it will fit in easily.
Lipo offers greater energy density than NimH, and can generally deliver a lot more current. Also, although the packs may be similar in size, I would expect the NiMH pack to weight a lot more, so this could upset the balance of your boat- note I said could, not will.
-
Thanks Andy. It was my estimate on the corner radii added to the H x W x D dimensions given, I knew it would be a close. Sadly too close to fit. Pity, it is a nice 4,000 mAh pack.
If you recommend I stick with the LiPo then I will do that. I am not sure what the design weight should be, but at least with a slightly smaller pack I can add ballast if necessary. This is all R&D after all. Hopefully starting assembly and wiring very soon, with pictures or course.
-
http://hobbyking.com/hobbyking/store/__11612__Turnigy_4000mAh_3S_20C_Lipo_pack_Perfect_for_QRF400_.html
Thanks for the tip on this.......I would love this in my Gato! I will file this for future use (after my current LiPo die off).
Cheers,
Tom
-
Unfortunately a bit too chubby for the 2.5" subdriver.
-
Oh, I was just looking at the depth (length). Guess I should have looked at all the dimensions! Thanks for the heads up!
-
Highly impressed with www.component-shop.co.uk. New LiPo ordered late Thursday. Arrived this morning.
Fits inside the 60 mm ID tube nicely.
Question: I assume the 4 pin Lipo socket on the battery (R/Bu/Y/Bk) is used purely for monitoring whilst charging ?
-
It's actually used for the charging. Each cell is charged individually. On some chargers you connect both the balance connector and the main battery connector.
-
Thank you for that info. This is all new technology to me %)
K9 now on the stocks
-
Hi Bob k,
The K class that was videoed at Barrow is mine, she is K22, is 7ft long with a co2 ballast system.
I am going to be at the Norwich dive on the sunday if you can make it.
I'll sort some pictures out soon.
Adam
-
Hi Adam. I remember that video. Very impressive. I must re-find the dates and info for this years Norwich event.
My own K9 has been on hold for a while, looking for an alternative battery type to Lipo that will still run it and fit in the limited space. In the mean time I have built a WW1 destroyer and a semi-submersible torpedo ram.
-
Hi Adam,
Looking forward to seeing you and your sub again (I took the video at Barrow) - very impressive sub. I seem to remember you carrying it under you arm !
I will be at Norwich both days with the R Class.
See you,
David
-
Hi,
Great build, anything First World War is always nice to see.
There are some photos of onboard a K Class on the Imperial War Museum web site. You can grab or download the images. They've added a lot of First World War and Interwar photos recently, worth a look.
http://www.iwm.org.uk/collections/item/object/205318769 (http://www.iwm.org.uk/collections/item/object/205318769)
-
Wow, thanks for sharing with us, and welcome to the Mayhem. :-))
With pictures like that I think me and Bob might complete our models!
-
That is a really useful photo. Thank you for posting it. Also, welcome aboard :}
I remain in an intermediate stage on such vessels, having recently achieved submergence (on a semi-submersible), but need to resolve the de-submergence aspects before intentionally heading out into the Gairloch.
-
Hi,
Great build, anything First World War is always nice to see.
There are some photos of onboard a K Class on the Imperial War Museum web site. You can grab or download the images. They've added a lot of First World War and Interwar photos recently, worth a look.
http://www.iwm.org.uk/collections/item/object/205318769 (http://www.iwm.org.uk/collections/item/object/205318769)
Anyone any ideas about the object sticking up between the 2 raised hatches. I might be crazy but it looks like a depth charge thrower. Then again if they're daft enough to build a steam powered submarine they're daft enough for anything.
-
That is indeed a depth charge thrower. I think this photo of it is from the Submarine Museum.
(http://i1143.photobucket.com/albums/n626/bobkiralfy/K%20Class/Kdepthchargethrower_zps16d99a60.jpg) (http://s1143.photobucket.com/user/bobkiralfy/media/K%20Class/Kdepthchargethrower_zps16d99a60.jpg.html)
They were also crazy enough to mount a 12 inch gun on one, and convert another to a seaplane carrier.
-
OK! So bombs designed to explode underwater on a submarine! Those guys must have been on something when they thought that one up!
-
OK! So bombs designed to explode underwater on a submarine!
Torpedoes are another kind of bomb designed to explode underwater. However, only the Americans could think of mounting a 22 ft spar torpedo on a submarine. The H.L. Hunley. It sank both the Housatonic and the Hunley.
-
True but torpedo are expected to hit something before exploding. A depth charge has a pressure sensitive fuse. Presumably the hydrostatic pistols in these depth charges were fitted with some kind of safety device and armed before firing. Having them live in the sub could cause all kinds of unpleasantness. Just doesn't seem like a bright idea to me!