Need some help with Arkmodel 1/48 Type VII

[tifosi12]

Just received the kit from China with a one piston tank. While some claim the instructions are great, I feel somewhat lost and it takes me quite some time to figure out what is meant by them.

So I think I'll need a lot of help from the community on here if I want to have this build ready for the August event at Carmel. I have built RC subs before so I know the basics but there are some details in this particular model that escape me and thus I'd really appreciate if somebody who has done this build before could help out. I googled the videos online but since Bob Martin put in his own WTC they won't really help me in this case and quite frankly I would have ordered a WTC from him if they were available, but no (and yes, that's a mild criticism to the shifting release date).




So here is my first of what will be many questions, I suppose: I got these cute little electronics with the motors (I supposed they are resistors, but I'm no expert) and I suppose they should be soldered onto the motors' plus and minus poles, but I'd really like to hear from somebody who knows, what to do with them. The manual is completely blanking on them.

BTW: I tested the motors with a battery and they run just fine. So I'm guessing these things are needed to prevent a spike in current or something. Maybe they are not needed? I remember having seen similar ones in a Caswell kit a long time ago.

Anyhow, your help is greatly appreciated. The countdown clock to Carmel is ticking in my head and I'm starting to slowly panic not to be ready for the big event (wanted to be there last year but you all know what happened).

[He Who Shall Not Be Named]

Just received the kit from China with a one piston tank. While some claim the instructions are great, I feel somewhat lost and it takes me quite some time to figure out what is meant by them.

So I think I'll need a lot of help from the community on here if I want to have this build ready for the August event at Carmel. I have built RC subs before so I know the basics but there are some details in this particular model that escape me and thus I'd really appreciate if somebody who has done this build before could help out. I googled the videos online but since Bob Martin put in his own WTC they won't really help me in this case and quite frankly I would have ordered a WTC from him if they were available, but no (and yes, that's a mild criticism to the shifting release date).




So here is my first of what will be many questions, I suppose: I got these cute little electronics with the motors (I supposed they are resistors, but I'm no expert) and I suppose they should be soldered onto the motors' plus and minus poles, but I'd really like to hear from somebody who knows, what to do with them. The manual is completely blanking on them.

BTW: I tested the motors with a battery and they run just fine. So I'm guessing these things are needed to prevent a spike in current or something. Maybe they are not needed? I remember having seen similar ones in a Caswell kit a long time ago.

Anyhow, your help is greatly appreciated. The countdown clock to Carmel is ticking in my head and I'm starting to slowly panic not to be ready for the big event (wanted to be there last year but you all know what happened).

Those are ceramic capacitors, and they suppress (by smoothing out) the voltage spikes common with motor that employ a commutator (mechanical switch). Typically you have one between motor case and one pole, another to the other pole and motor case, and a third between the two poles -- but I find this third capacitor to be redundant and usually don't bother with it. This arrangement is called 'spark-suppression'.

Unfiltered, a brush type motor (of which you have) will send those voltage spikes up and down the circuitry and fox both receiver and other devices sensitive to such RF noise. The capacitors prevent most of that noise.

Your talk'n to the guy who made the Caswell SD's. Here's How I connect the cap's to the motor poles and case (ground):

[Monahan Steam Models]

I picked up one of Arkmodels piston tank WTC kits a while back for a lower price than typical retail. I liked the idea that it was designed to fit the type VIIC and was curious if was any good.

Although I assembled the WTC, I was skeptical about the piston tank’s volume being enough to properly trim the boat. I also found casting shift between the inner and outer dies that form the clear end caps for the WTC. This caused significant binding for the motors and shaft seals as well as the alignment for the pushrods and seals.

In this thread I posted so findings and fixes: https://forum.rc-sub.com/forum/gener...question/page2

The thread is not finished as I moved on to the work being done on the hybrid ballast system posted in the general forums section.

I agree the instructions are not great but you may run into other issues you’ll need to address using their WTC kit.

Nick

[tifosi12]

Your talk'n to the guy who made the Caswell SD's. Here's How I connect the cap's to the motor poles and case (ground):

What an honor, ey! Thanks a lot for all your comments and pictures. Made it crystal clear. Will follow your recommendations.

[tifosi12]

Although I assembled the WTC, I was skeptical about the piston tank’s volume being enough to properly trim the boat. I also found casting shift between the inner and outer dies that form the clear end caps for the WTC. This caused significant binding for the motors and shaft seals as well as the alignment for the pushrods and seals.

In this thread I posted so findings and fixes: https://forum.rc-sub.com/forum/gener...question/page2

Thanks for that as well, will study your comments. Doesn't give me much confidence though. Oh well, I'll try.

[Monahan Steam Models]

I believe it is entirely possible to end up with a functional Arkmodel WTC if you go into the project knowing that there’s a strong chance you may need to make some custom modifications.

The dimensions of these particular batteries fit the Arkmodel single piston WTC as it was designed.

https://www.amazon.com/gp/aw/d/B08JH53LPY?psc=1&ref=ppx_pop_mob_b_asin_image

[TuptubBuilder]

Warning Warning Warning! Do not try to press fit the 2 mm bushings for the servo rods. I found that the interference fit was too great and it cracked the PVC. I had to graft a polycarbonate substitute (see picture).
Drill out the bore to make a slip fit. I think it was 5 mm.

The grossest design problem is the difficulty in accessing the WTC. I added a bulkhead with connector plate and used hex standoffs with slots (also see pics).

[tifosi12]

Installed the motors and their silicon sealant cups last night. The seals are so tight, they actually stopped the motors from turning. I realized what happened when smoke came up.. This isn't going anywhere good. :(

[Monahan Steam Models]

Installed the motors and their silicon sealant cups last night. The seals are so tight, they actually stopped the motors from turning. I realized what happened when smoke came up.. This isn't going anywhere good. :(

Sorry to hear that. The binding was most likely due to the casting shift in relation to the molds that form the inner surfaces and the mold that forms the outer surfaces. Because of this, I found that the bores that interfaces with the motors are not concentric to the bores that hold the seals as I wrote in the thread that I linked earlier.

There is a fix for this that I was planning on posting months ago but I just have not had time with my focus being on other projects. The fix involves creating a bushing and seal cartridge inside of a length of K&S thin wall tubing that slides on to the motor shafts and into the cup seal bores of the clear molded WTC aft compartment. The outside diameter of the seal cartridge is slightly smaller than the inside diameter of the counter bore that would normally hold the kit’s original cup seal. This allows the seal cartridge to be concentric to the motor’s shaft and the cartridge is then secured or potted into place with silicon or rtv sealant.

Nick

[tifosi12]

Yeah, this will be added to the pile of never-to-be-finished projects. By now I have more cancelled sub projects than actually running ones. I'm sure I'm the only one with that track record. :)

[He Who Shall Not Be Named]

Yeah, this will be added to the pile of never-to-be-finished projects. By now I have more cancelled sub projects than actually running ones. I'm sure I'm the only one with that track record. :)

No. Sadly, your experience is typical. MOST guys who venture into this form of r/c vehicle activity soon find themselves in a wilderness of bad advice, poor product availability, and no experts next-door to guide you through a successful completion of a project. Welcome to r/c submarining, pal! This remains, pretty much (Bob is trying to change this), an activity for loan-wolfs.

What's your history? What kind of r/c vehicles did you successfully operate before getting into this game? Is this your first attempt at r/c submarining? What's your skill level with adhesives, hand-tools, soldering, and understanding of basic physics, electricity, and materials characteristics.

Tell me these things and I can give you a steer towards a project you can handle and see through to a successful conclusion.

Take a few breaths. Re-group. And try again, under my wing as I bodily drag you screaming and blubbering into the hobby. You don't need advice as much as a useful, informed, kick in the ass.

The other posters -- who have been attempting to help you along -- were too kind. They told you nicely. I'll give it to you straight: That 1/48 Type-7 internals kit is a screaming pile of ****.

You chose poorly. https://youtu.be/Ubw5N8iVDHI

David
The Horrible

[tifosi12]

No. Sadly, your experience is typical. MOST guys who venture into this form of r/c vehicle activity soon find themselves in a wilderness of bad advice, poor product availability, and no experts next-door to guide you through a successful completion of a project. Welcome to r/c submarining, pal! This remains, pretty much (Bob is trying to change this), an activity for loan-wolfs.

What's your history? What kind of r/c vehicles did you successfully operate before getting into this game? Is this your first attempt at r/c submarining? What's your skill level with adhesives, hand-tools, soldering, and understanding of basic physics, electricity, and materials characteristics.

Tell me these things and I can give you a steer towards a project you can handle and see through to a successful conclusion.

Take a few breaths. Re-group. And try again, under my wing as I bodily drag you screaming and blubbering into the hobby. You don't need advice as much as a useful, informed, kick in the ass.

The other posters -- who have been attempting to help you along -- were too kind. They told you nicely. I'll give it to you straight: That 1/48 Type-7 internals kit is a screaming pile of ****.

You chose poorly. https://youtu.be/Ubw5N8iVDHI

David
The Horrible

I've been building R/C planes, tanks, ships and was big into High Power Rocketry, where I learned a good deal about manufacturing and electronics. My understanding is fairly good, where I'm weak at is fabrication like you are doing with your tools etc. So in essence I can follow directions and assemble a kit by the book but I couldn't scratch build the parts for it. At least with 3D printing I have now a bit of a break in that.

My first project was a 1/72 Type VII Revell conversion using your fittings kit. That almost worked: The sub is working except for taking left turns where the rudder is more flapping in the breeze than anything (oddly enough right turns work fine). Then I tried the XXIII type using your Caswell WTC. Looked all good but for the life of me I couldn't get the cut of the upper hall straight. Tried it three times and thus successfully destroyed three perfectly fine kits. So the Arkmodel Type VII is a good choice as it is a by the numbers build. Except for this darn WTC. I didn't know that the thing required assembly. I had one from Engel before and that was a disaster as well.

So I do think I know what I can and cannot do. Given a nice WTC from you or Bob I'm sure I could bring the Arkmodel to a successful end.

In regards to regrouping: No worries, your Caswell WTC is already waiting for a new project where I 3D print the boat. Not trivial but has a higher chance of success than trying to mod an existing plastic kit. As long as I have something working for Carmel I'm fine. Few months left to go.

What really ticks me off about this hobby is what you mentioned: The many bad products out there. You don't get that when you build a tank, racecar, plane, ship. Those kits are all straight forward for the most part whereas with subs the good kits are the exception. Sucks. Somebody should fill that niche. We don't need a RTR sub but something that doesn't need a mechanics and engineering degree in the assembly.

PS: We "met" on Bob's dive tribe. So I'm not scared by your tough sailor's talk. :) But thanks for taking the time to help a newbie.

[tifosi12]

And Dave: Thanks for the last comment about the screaming pile. That was helpful as it made the departure with it much easier. I just wish I had known that before sinking all the $ into it. Oh well.

[He Who Shall Not Be Named]

And Dave: Thanks for the last comment about the screaming pile. That was helpful as it made the departure with it much easier. I just wish I had known that before sinking all the $ into it. Oh well.

You still wana play?

Or do you need to cower in a designated 'safe-place' (check your local Collage) as you stroke a certified dog/cat/iguana/miniature pony/scorpion/duck/snake service-animal as you make cooing sounds to it for a day or two?

Whistle me up when you're ready.

[Monahan Steam Models]

David said what I wanted say. The Arkmodel WTC is a pile of ****. Move on and cut your losses. Sure you can make custard out of cow **** but why?

Once you’re done cooing your certified spirt animal in your safe place, take the man’s offer to to help you if you really want to learn from the best.