Forum rules and expectations

Hello, and welcome to the forums at the Nautilus Drydocks, formerly!

We welcome anyone with a passion for submarines and a desire to learn and share knowledge about this fascinating hobby. Use of these forums indicates your intention to abide by our code of conduct:

1. No spam. All automated messages, advertisements, and links to competitor websites will be deleted immediately.

2. Please post in relevant sub-forums only. Messages posted in the wrong topic area will be removed and placed in the correct sub-forum by moderators.

3. Respect other users. No flaming or abusing fellow forum members. Users who continue to post inflammatory, abusive comments will be deleted from the forum after or without a warning.

4. No threats or harassment of other users will be tolerated. Any instance of threatening or harassing behavior is grounds for deletion from the forums.

5. No profanity or pornography is allowed. Posts containing adult material will be deleted.

6. No re-posting of copyrighted materials or other illegal content is allowed. Any posts containing illegal content or copyrighted materials will be deleted.
See more
See less

Kilo Conversion Blog

  • Filter
  • Time
  • Show
Clear All
new posts

  • Kilo Conversion Blog

    I'll be recording my experiences with the Trumpeter Kilo Conversion here. I'm using Dave Merriman's WTC as the basis for the conversion. (There are other WTC options, but Dave gave my kids their introduction to R/C subs, so we're going with his proven set-up.) The boys have R/C experience with cars, park fliers, and helis--but have the most time on cars. We also poured over Dave's Cabal Reports on the Trumpeter conversion. This seems an essential resource in taking on this project. The cabal reports are most easily found in this forum under Dave Meriman's Cabal Reports or you can take this short cut:,5,10

    We started with the Kilo WTC, Kit, and fittings: (For those keeping tabs, that's a $500 entry fee.)

    What's not clear to noobs like me is the requirement for some extras, like fail-safes and pitch controllers. ($95 for a unit with these combined functions).

    It should be pretty clear that you'll need some sort of command and control system. Caswell sells a transmitter receiver package that seems both well suited for the task and well priced, too. My son wanted to use his Helicopter T/R (Futaba 9C Super) and the SL-8 Receiver sold by Caswell ($64). Since both units have synthesized transmitters and operate on 72MHz, they should be able to talk to each other.

    Our first road block is in connecting the WTC up to the receiver. We haven't found much info on which servos get plugged into which receiver pins. (Instructions for this didn't come with either the WTC, nor with the receiver.) I suppose this is just so well known by the experts that they don't even think to mention it. I suspect that there's so much to the electronics side that it deserves its own thread, if not its own topic area. (I've started a thread in the appropriate area (Model Building Equipment) for this element of the discussion.)
    Last edited by Outrider; 09-14-2008, 09:45 PM. Reason: Added a URL to the Cabal report and added a thread reference to the Model Building Equipment area.

  • #2
    Re: Kilo


    Not really sure you've found info on that receiver. I have a Futaba 4 channel Transmitter with Novak receiver and a Novak Speed controller. For Dive planes and Rudder you can use Bluebird BMS 371 servos that should be sufficient to activate your dive planes and servo. I hope this helps! JC.


    • #3
      Radio Set Up

      I'm using nearly everything from the Meriman / Caswell Cabal, since I've seen it work, and work well. The Caswell site has a lot of information posted on each product page, though some items, like the SL-8 don't have as much info as I wanted. Fortunately, there's Google. Sombra labs is easy enough to find, and they post some instructions on the SL-8.

      I'm using a Futaba 9C Super because my son wants to use it. I thought it was simpler to just buy the combo that Caswell sells. But this project should be educational (for both of us) and the Futaba should work (72KHz synthesized FM and PCM capable). I still have to figure out which servos go to which receiver channels and I also have to get the Futaba and the SL-8 to talk to each other. Will come back on line when we sort that out.


      • #4
        Re: Kilo


        As far as I know, 72 mhz will not work for under water transmission. 72 is for surface/Airplanes. I am using 75 mhz with either 1st 3rd or 4th channels for my dive plane and rudder. I am building mine using Dave's Welch WTC and fabricated all the necessary parts that go with it. JC.


        • #5
          Frequency (72 MHz) and Pushrod Fabrication

          I doubt there are any transmission issues with 72MHz, since it's a lower frequency than 75MHz. Higher frequencies run into physics problems. For example, 2.4 GHz is a no go because water absorbs practically all of the RF energy transmitted on this frequency--that's why it's the frequency of choice for microwave ovens.

          I'd be interested to hear how the build goes with the Welch set-up. So far I'm happy with the items I've received from Caswell, but there are a few bits that don't seem to be included in the kit, such as all of the pushrods for the control surfaces. These parts seem easily fabricated--they're just bent rods--but more guidance would be welcome, such as suggested diameters, bend points, etc. I suspect we'll have no problem with these items, but as of now we're back in research mode.

          (BTW, we still haven't sorted out the transmitter/receiver issues, but my son has lost his patience and punted...)


          • #6

            Dave Welch's conversion takes lots of patience and patience is definitely not for the fainted heart.
            I thought the sub-diver system from Caswell includes everything you need to build that sub. I guess you did not purchase the fittings kit. Anyway, my push rods materials include 1/16" K& S Brass Rod and 1/8" K & S brass Tubing with 1/16" ID. You will probably need some collars( dubro139 1/8" 137 for the 1/16") with set screw on the 1/16" rod and 1/8" tubing. As far as the bends, if you have a micro needle nose and a needle nose one size up, you should be able to produce the bends that you'll need in order to activate your dive planes and rudder. Of course a bit of soldering skill will not hurt from 1/16" to 1/8" Brass tubing. That is pretty much on the push rod of the experience I have.
            I was using a door hinge to hold those two servos but I've decided to purchase a L Bracket that closely match what I need in order to hold those two servos down good. For Motor, I will be using GWS/LPS-RXC-CS with an adaptive space in order to keep the motor from moving.
            Ballast tank is a bit challenging for me but I am going to use the ES2 switch and a 6VDC soleniod valve from Caswell in order to inflate and deflate the bladder. Regards, JC.


            • #7

              We bought everything from Caswell and have been pleased so far. What's missing with regard to the pushrods is data regarding the diameter and dimensions. We took the fittings with us to our local hobby shop and purchased rod that fit. I think it's 3/32 for the brass rods and 1/16 for the Aluminum. Since we have some RC experience with planes and helis, we have some useful tools, such as Z bend pliers, which should help us make the rods.

              We'll take the time to record and share what we think works for control rods as a contribution back to the community. Dave Meriman's notes to the cabal on his Kilo seem useful to anybody attempting a conversion, regardless of the WTC being used. They just don't mention this particular aspect of construction.

              The Caswell/Meriman WTC (oops... SubDriver™) seems really easy to work with, since it's got everything installed, except the electronics. (To be clear, the servos, which I consider electric, vice electronic, are installed as well.) In my view, Meriman's WTC is a nearly complete submarine in its own right--just needs the slip on cosmetics that really are best left to the injection molding houses.

              The SubDriver is an excellent design and the fabrication is top notch, too. I want Dave working on SubDrivers and modification parts like those he's done for the Kilo. I don't know if that's the optimal use of Dave's time--Ellie or Dave probably knows that best--but the time he spent making the Kilo parts and SubDriver certainly have been of value to me. (I'm so grateful that I'll probably wait another whole day before I ask where the 212 SubDriver and parts kit are.)

              My oldest son is having a blast with the project, even though he wanted a "real" U-Boat first.
              Last edited by Outrider; 09-14-2008, 10:03 PM. Reason: Needed a bit more clarification...


              • #8
                Minor Update: Radio Setup is Good, Now for the Swiss Cheese

                My son got his T/R in sync with the SL-8 receiver. (See the model building equipment thread for the full story.)

                Next up is drilling holes in the bottom of the Kilo. My son has made it clear that he's not burdened by trying to faithfully replicate whatever drainage holes are on the bottom of a real Kilo. That said, I don't want him to Swiss cheese the bottom, either. Two questions:
                • Anybody have a good photo of the real thing, just to see what is accurate?
                • Anybody have a recommended pattern for bottom hull drainage for the Kilo (number, size, and spacing/positioning of holes)?

                One we get drainage resolved, the hull is basically ready. We've misplaced a few parts (Kli-cons) and the ADF (an expensive thing to lose track of), but have put those parts on order and hope to see them soon.


                • #9

                  I thought I saw in the CAB report about step by steps of drilling the holes;however, I am using different approach so drilling the holes is not require for me. JC.


                  • #10
                    Holes Drilled, Sub Gets its First Bath

                    I found some shots of Dave Meriman drilling holes in the bottom of his Kilo in one of the Notes to the Cabal. This gave us a rough idea of what and where to drill. My son took his sub to his High School engineering club and used a drill press to cut out the appropriate slots. Photo is attached, since I had to bring him the sub and to act as a human clamp for the drill press.

                    We got a partial shipment yesterday in from Caswell that contained the missing bits we needed. My son had it opened before I got home and was quick to get the parts installed. We ran into one problem regarding the prop shaft and the dog bone coupling--the combination is about 1/4 to 1/3 inch too short, so we need either a longer prop shaft or a longer dogbone. Looks like it's time to find some appropriately sized stainless steel rod. Fortunately, we hadn't glued the prop to the shaft yet, so we didn't risk the nice prop that comes with the kit.

                    Also, we have 1/8 inch couplings, which seem too big for the prop shaft, because the coupling is noticeably off center. This could be fixed by drilling and tapping a second set screw in the coupling--this would allow the coupling to be centered on the shaft and take the dogbone out of its eccentric orbit. One more series of items for the to do list.

                    We also need to work on static stability, as the sub is rolling to starboard. Buoyancy issues are still on the plate, too. We need to sort out how much and what type of ballast we need, as well as where to place it. This type of info would be nice to get out with the Kilo Sub Driver, so we'll offer it up when we get it.

                    We're happy to get input on any of these issues.
                    Attached Files
                    Last edited by Outrider; 10-02-2008, 11:06 AM.


                    • #11
                      Anybody Can Get a Sub to Submerge...

                      The trick is getting it to come back up when you want it to.

                      My son is still sorting out ballast. His initial try was with a dry ballast tank (no Propel gas in the copper tank). What did he discover? Goes down, but doesn't come back up. No problem in a shallow bath tub, though.

                      Next thing he discovered is that he needed to have the propel can upside down when filling the ballast tank. Remember, you want the liquid in the copper tank, not the gas. But liquid weighs more than an empty tank, so it was back to weights and balances. Let's hope Caswell comes up with a ballast kit for the Kilo. As of now, it's buck shot in baggies for our Kilo.

                      He also discovered that the resin dogbone coupler on the WTC doesn't particularly like coming in contact with tile floors, even from a small drop. Luckily, we had a spare brass coupler on hand.

                      Next up is getting the rest of the linkages cut to their final lengths and CAed to the Klick-on connectors.


                      • #12

                        Nice to see a kid getting involved in this game. Anything I can do to help you guys?

                        Resident Luddite


                        • #13
                          I too am currently doing my first Kilo conversion( in fact my first ever RC project). Thanks to Dave's excellent fittings things are much easier. With my Kilo I plan to incorporate a thrust bearing to the end of the hull to minimize shaft play. Hope to post my work pics soon.
                          Make it simple, make strong, make it work!