TAMIYA'S 1:16 KING TIGER KIT

tamiya king tiger cannon flash

07/08/09- Woo hoo! The Tamiya King Tiger arrived just in time for the long 4th of July weekend... much to my wife's dismay since she knew that home improvement projects would take a backseat to my new toy. Building a kit isn't everyone's idea of "fun" since it has the semblance of "work" in its repetition, like priming parts for 18 wheels, assembling them and installing them. It's the kind of tedious and time-consuming stuff that only a hobby geek would enjoy. That's mixed in with a fair amount of Internet research for reference photos, to see how others have tackled the project, and for those important before-you-start tips... and then placing orders for stuff that you think you'll need or want later. (For instance, it makes sense to install ball bearings the first time through, instead of assembling the wheels with the kit's bushings, then dissassembling them later to install the bearings.) The payoff is connecting a battery to the half-finished tangled mess of wires and witnessing the thing come to life. Sweet!

Tamiya King Tiger

The Great Heng Long Versus Tamiya Debate: I have to admit that I got this kit because I'd read so many forum posts with references to the dreaded "Tamiya versus Heng Long" debate. It's a topic that few dare to revive, so I suspect that it has been discussed many times before, ad nauseum. I missed all of that and since I only recently got into the hobby with purchases of Heng Long's Tiger I (apparently an older version, bought at Hobbytown) and their Panzerkampfwagen IV, purchased from RC Command (Bill's a great fellow Texan!). I've spent (and continue to spend) an additional minor fortune buying and installing upgrades for those. At any rate, I was curious about Tamiya's 1/16 scale tank offerings. Consensus seemed to indicate that they were a gold standard of 1:16 RC tanks; though expensive, one wouldn't need to spend lots of money on upgrades to get a reliably-running tank... however, one could easily spend gobs of money on non-essential detail parts and running gear upgrades (as I found out). The crux of the debate is over whether it's better/smarter/makes-you-a-superior-person to buy an expensive Tamiya or an economical Heng Long, and upgrade as you go. Groan...

My Heng Long Tiger was a challenge from Day One: It needed replacement suspension arms out of the box since some had cracked (plastic). The aftermarket metal suspension arms were a nightmare to install because the plastic wheels were attached to the arms by pins that had to be hammered in. The circuit board fried during the first week during a routine turn on carpet. All these problems were fixed of course, and as insurance against future problems, I ordered a metal lower hull & wheels, which cost more than the tank.

After that experience, the attraction of Tamiya's King Tiger was that it came stock with most of the stuff I'd replaced on my Heng Long Tiger. Since I was interested in exploring the infrared battle option, it made sense to buy theirs. Tamiya is the de-facto standard that third party systems strive to be compatible with. With the Tamiya, I would spend more up front and get a single source solution instead of initially saving money but having to spend more to upgrade with third party products.

It's silly to say that one path is better than the other, since interests and personal circumstances differ. Using the Mac/PC analogy, there's some satisfaction to be had from the higher level of technical expertise and problem-solving required to make things work together on a PC than the relatively tame and controlled environment of a Mac. Even though the Tamiya tanks come as kits, there are very few aftermarket mods required to make it work well, so it requires only the ability to follow the Tamiya-supplied recipe of Tamiya-supplied ingredients. (Of course, you can also spend lots of money on aftermarket parts for your Tamiya build!) The irony is, to bring a ready-to-run Heng Long up to that standard requires broader technical and problem-solving skills than to build a Tamiya. Again, like in the PC world of yesteryear, there's no guarantee that the aftermarket parts you buy will have drop-in compatibility. That's where problem-solving skills come in handy.

THE BUILD PROCESS

Tamiya King Tiger One of the things you should think about before you begin is how you'll use the tank. Even though it's an RC tank, there are enough superdetailing options so that you can decorate the exterior nearly as thoroughly as a static model kit (short of gluing the tracks in place and slathering them with fake mud). That's probably not the best approach to take if you intend to run your tank outdoors where delicate parts can be knocked off or fall off-- once they're lost somewhere in a lawn, don't expect to find them because the camouflage colors really work! I gravitated towards a middle-of-the-road balance of a backyard runner; it's doubtful that I'd ever do full competition battling, but I still wanted a tank that would perform well and reliably, with a detailed but fairly durable exterior that I didn't have to worry too much about.

The bulk of the build took about 3 weeks, much of that time spent waiting for parts to arrive. At the outset, there were some recipe changes I wanted to make, and I knew I'd think of others as the build proceeded. It's best to plan before doing so you don't have to undo stuff that you did in haste. Inevitably, planning leads to buying and waiting for parts to arrive, so that dictates what you can work on. Generally speaking, I bought what I thought were the most important upgrades first, placing priority on the functional aspect of the tank (One exception-- I really like photo-etched grills). Of course, you learn stuff as you build, so advanced planning can only anticipate so much.

Wheels: It's common sense that you want the wheels to rotate as smoothly as possible, with as little friction as possible for smooth operation and to minimize wear (nevermind that plastic wheels on metal shafts can make a very neat, realistic tank squeal sound!). I bought some sealed ball bearings from ETO armor which were to replace the kit's 2 kinds of bushings. I figured out what to do with the flanged bearings, but the second bearings had a wider opening that didn't seem to fit anywhere-- puzzling, and I don't think I overlooked anything obvious. Fortunately, the full-option kit's wheels are screw-assembled (not glued), so I used the stock bushings and moved along. (About a month later, I figured out that the second bearing that I hadn't used could/should be used as a spacer to keep the wheel from wobbling. In that capacity, it doesn't matter that its opening is wider, since it's not being used for its qualities as a bearing... whew! They really should provide instructions for this stuff!)

Idlers: I'd read that the stock idler's design was not very reliable (would loosen and slip) and discovered that they were not very easy or intuitive to adjust, with a limited adjustment range. They're over-engineered (which makes them look impressive), but the idlers serve a practical, functional purpose: They make sure that the tracks have the right tension so that they stay on through turns and difficult surfaces, and can accommodate small stones & twigs without stalling the tracks (very bad). They also make it easier to install/remove tracks without removing track link pins. I thought I'd give Tamiya's a chance, but decided that the drive train was one of the most important parts of the tank if you're thinking about running metal tracks: I replaced them with Darryl Turner's clean and simple design. I'm glad I did because they've worked great.

Tracks: I'd read that Tamiya's plastic tracks were a good, practical choice-- they're lightweight and work well, they're cheap and easy to replace should they break. On the other hand, Tamiya's King Tiger seems to get mentioned most consistently as having the worst of Tamiya's plastic tracks. No matter: I wanted metal tracks, despite the bad things that the additional weight does for the idler and gearbox. I'm not a metal fetishist (I think that plastic hatches work as well as the metal ones once they're painted) but metal tracks just feel and look more substantial to me.

In preparation for this, and as a generally good thing to do, I reinforced the gearbox mounting. If you push the drive sprockets inwards and outwards, you can see that the gearboxes and hull move, which isn't a good thing. My home-made remedy was to put strip of brass between the gearboxes (so they don't flex inwards), with a slotted brass tube over the top (so they don't flex outwards).

It was a spur of the moment thing, but I bought Impact's Late Version 18-tooth sprocket & track set. I half-regretted it once I started doing some research and learned how "late war" they really were. The good thing is that late war King Tigers didn't have zimmerit (a stick-on version was included in the kit but I didn't want to use it on this tank), but the bad thing is that very few 18-sprocket tigers made it outside the factories before they were overrun by the Allied forces. For historical accuracy, that really limits the decoration choices, and there are a few other details that would need to be altered to make it accurate (track hanger layout on turret, front fender reinforcement, rear hatch shape, 4-fuel filter lines & lack of hydraulic jack, etc.). I decided to use the tracks, and not worry about trying to replicate a historically accurate King Tiger. In fact, I decided to use the 9-tooth sprockets with them since I think they're less prone to slippage.

I later bought some metal "Transport" tracks after seeing how nimble they made the tank. They don't look as good, but they're thinner and lighter than the combat tracks, and more durable than the plastic tracks. If I were involved with IR tank battling, I'd probably put these on.

The Transmitter: One of the things that factored into my decision to get a Tamiya tank was that the kits didn't include a transmitter... and since I was a failed helicopter pilot, I had an older Spektrum DX6 transmitter with some nice features that I really wanted to use. I did some preliminary research that indicated (sifting through conflicting reports) that the DX6 would work. The only recommended change was to get a newer receiver, the BR6000, since that would better handle a transmitter shutdown than the AR6000 installed in my helicopters. (With the AR6000 installed, if you turn off your transmitter while the tank is on, one of the channels will stay alive, resulting in a runaway tank or an endlessly rotating turret.)

Fortunately for the DX6 user, there's some good tank-specific info out there, much of it from DAK. Unfortunately for the novice, there's not quite enough of all the pieces in one place.

Channel Mapping: The first obstacle is figuring out what wires to connect & where. Tamiya's DMD module has servo connectors labeled in a hybrid aircraft/tank style. The BR6000 uses the conventional aircraft labeling. The challenge is figuring out (1) what the DMD's wired plugs are supposed to control on the tank, and (2) what the BR6000's servo jacks correspond to on the DX6 transmitter. The third thing is to figure out is how you want your transmitter to be set up. I'd gotten used to Heng Long's setup (which is nothing like the setup Tamiya suggests), so I wanted to configure the DX6 to match it.

This configures the transmitter with turret/fire controls on the left stick, and drive controls on the right stick:

DMD CHANNEL & NAME BR6000 CHANNEL & NAME MAPS TO X-MITTER FUNCTION
(1) RUDD (2) AILERON RIGHT STICK LEFT/RIGHT Drive: steer, turn
(2) THROT (3) ELEVATOR RIGHT STICK UP/DOWN Drive: forward, reverse
(3) MGUN (1) THROTTLE LEFT STICK UP/DOWN Main gun elevation; quick full up= cannon fire, quick full down = machine gun
(4) TURR (4) RUDDER LEFT STICK LEFT/RIGHT Turret rotate

What this means is that if you plug the DMD's channel 1 (named "RUDD") into the BR6000's channel 2 (AILERON), the right stick will control the turn direction.

Cannon and Machine Gun Fire Control: Tamiya's gunfire procedure involves adjusting the trimmer before firing, which is kind of clunky. Since the DX6 has digital trimmers that are more precise but slower to adjust, this isn't practical. Fortunately, the DX6 is programmable, so it's even easier: Set the range of the channel (in my setup, that would be throttle, which controls gun elevation) to +150% (up) and -150% (down). (Note: Make this change after you've run the DMD's calibration routine or the DMD will calibrate the gun elevation to the full -150 to +150 range, without cannon and machine gun fire.)With a quick left upstick motion, the cannon fires; quick downstick motion fires the machine gun. The only catch is that you've got to return the stick to center after firing, or the gun elevation will be triggered: Standard DX6s don't don't come with a centering mechanism on the left stick.

The DMD module does have an adjustment so that you can widen the "dead zone", so the elevation isn't triggered as easily. However, it would be even better if the left stick were self-centering too. Horizon used to make this modification for free if you requested it at the time of purchase. They don't make DX6s anymore, and I don't know if they still offer this service, but I've read that they don't sell the parts for do-it-yourselfers.

Once again, Google comes to the rescue. Smart folks have figured out that all you need to do is trace and reproduce the shape of the part from the right stick centering mechanism and add a spring. The forums even show pictures of the process. My suggestion: Trace the original part with spray paint onto a thick piece of styrene and cut it out with a Dremel, making sure that the half-circle cut in the center is deep enough, or you won't get crisp centering. It's fairly easy to do, especially if you're a packrat with a bunch of springs to pick through.

Snooze Control: Da-yum!!! Full credit goes to DAK for figuring this one out! This is a cool feature that uses one of the DX6's 2 extra channels to put the tank to sleep remotely. Basically, you insert a radio controlled switch ("Pico switch" from Dimension Engineering) instead of a servo into one of the BR6000's extra channels and use this switch to turn off/on the control line of the DMD's Rudder channel (in my case, that would be the BR6000's Aileron channel). When the control line is interrupted the tank powers down with the appropriate sounds. When you switch it back on, the tank roars to life. (Note that this doesn't actually turn the tank off-- it's still consuming power and operating the receiver and switch.) At this point, you can turn off the transmitter and if you've binded the radio and receiver with the switch off, the failsafe will keep the tank asleep until you turn on the transmitter. Cool! Get the .pdf (and others) from DAK's Radio Room. They provide really good and clear instructions.

Tamiya King Tiger lightsLight Control: Lights are a fun, low-maintenance feature and there are at least a couple of places you can add lights to Tamiya's King Tiger.

The King Tiger kit's headlight is three plastic parts that you're supposed to glue together, but you can do a little drilling and wiring before you do that. Grain-of-wheat/rice bulbs will probably fit, but they don't have the lifespan of LEDs, and this isn't a bulb I would want to change. I think that the only kind of LED that will fit is a smaller-than-a-match head surface-mount LED, and if you can find one pre-soldered with tiny, tiny wires, the rest is just a matter of drilling holes in plastic. If not, and you're not adept with this sort of thing, then practice soldering eyelashes on gnats. It doesn't take much heat to cook a SMD LED, so you can't dwell very long with the soldering iron. (Actually, the first challenge is unpacking the little buggers, because they have a habit of flinging themselves out of the packaging into the carpet, where you'll never find 'em.) Tip: Before you glue the drilled out front cover, paint the LED a yellowish color. The blue-ish white LEDs look like Zenon lights.

The convoy light (which is a little too bright in the pic) gets a similar treatment except you have to grind off the kit's cast light detail and find a clear tube to insert the blue-painted SMD LED into (paint brush bristle protectors work well). In this case, you have room for bigger wires, but tiny wires are probably easier to solder onto the LED.

Lights are an obvious choice for the last receiver channel, again using a Pico Switch to remotely switch them off and on. Although I didn't do it, it's a good idea to add a physical switch while you're at it, so you can easily convert to a manual system and reuse the channel if a better idea comes along. Lighting is one of those things that you probably will turn on a few times for the gee-whiz factor, but leave off or on most of the time. [10/01/09- The lights were moved to a slide switch so that the channel could be used to switch between the hull and turret machine guns.]

The DMD has an unused socket that can supply power for lights (or you can tap straight from the battery). I believe it's maybe 7 volts DC(?). I constructed a simple circuit using 2 diodes, a 5-volt regulator and a couple resistors (based on a slot car lighting circuit) to bring the voltage to a level appropriate for the LEDs.

Big Caution: When you uncap the CN5 socket, you run the risk of accidentally plugging the IR Emitter diode into it, since they're both 2-pin sockets and next to each other. This will fry your IR Emitter the instant that you power up your tank! Fortunately, Radio Shack sells a replacement (High-Output 5mm Infrared LED #276-0143) that appears to work fine and it only costs a couple of bucks.

Gun Elevation, Turret Rotation and Recoil: I saved all this stuff for last in the basic assembly, after I'd cut hatches open and planned for how I might install the IR battle system, and thought about how I was going to paint it. I didn't want to do any permanent one-time glueing until I was sure that I wouldn't regret it later; assembling the barrel seemed like that kind of step, so I put it off for as long as I could. So when I finally decided to bite the bullet, I worked straight through on all this stuff, confident that everything would work as well as the drive section had, once I powered it up. I was just a little disappointed...

Tamiya King Tiger recoil mechanism
Recoil Upgrade: 10/22/09-- I'm a little hesitant to recommend this since it does lessen the reliability of the recoil mechanism. Basically, it replaces a totally reliable gear-driven function (pulling the barrel back) with a less-reliable spring-driven function. As you can see, the spring is stretched an unhealthy amount. Springs weaken when they're kept stretched out and lose "springiness". The spring has to be just right for this to work because full snap-back travel is necessary for the gear's teeth to engage and bring the barrel back into battery. If it snaps back 99% of the way, the gear won't engage and the barrel will remain retracted until you manually push it in for the last bit of travel. If you use too heavy a spring, the motor/gear will have to work extra hard to bring the barrel back into battery. Therefore, the system has to be well balanced to work reliably. Such a problem developed after a couple weeks of reliable operation; my solution was to bend the rearward spring retaining tab back and downwards. This increased the spring tension, but also aligned it closer to the axis of the barrel's travel: The closer, the better.
First, the positive stuff: Tamiya's recoil mechanism with synchronized sound and flash unit is cool! I have no major complaints about it, and it's a compelling reason to buy a single-producer solution: Everything was designed to work together in synchronization. My Heng Long Pzkpfw IV with aftermarket solutions doesn't come close. If there's one quibble, it's the symmetrical recoil motion-- one expects the recoil of firing to be faster than the return to battery. The fix involves shaving teeth off the recoil gear and adding a spring, or buying an aftermarket kit (Impact makes one) that also includes a voltage regulator so you can fine-tune the return speed. It's a cool upgrade (although, see sidebar).

The turret rotation... well, it's depends on who you listen to, and it seems that quite a few people have problems with it. Some folks complain that it doesn't work as well as the over-engineered design would seem to indicate. The complaint is that the gearbox is barely up for the job-- the plastic gears are supported in a thin metal housing that can be bent with minimal finger pressure. This is a problem because the turret gear's teeth are on the inside surface of the turret ring, and the mechanism is anchored to the outside of the ring, with a gear driving the inside surface teeth, so the soft metal may tend to spread apart. A DIY solution comes from SEAD, who recommends wrapping a nylon cable tie around the assembly to strengthen it.

Another thing that folks complain about is the use of a clutch gear in both the rotation and elevation gearboxes. This slips (by design) with a clicking sound. Two solutions are proposed-- glue or replace the clutch gears in gearboxes. Replacement fixed gears (the blue ones) are available in Tamiya's 6-Speed Gearbox HE kit (a general science/experimentation kit). If you do this, know that Tamiya deliberately used the clutch gears to protect the gears from stripping if the turret or barrel get stuck and can't move. To help avoid this, for the elevation unit, you can remove the endpoint tab on the recoil unit that the elevation assist spring connects to and shave a little bit off of the nylon linkage socket. The elevation cam/arm will rotate 360 degrees, bringing the barrel up and down with either up or downstick (which can be a little confusing, but it's not a big deal). Another solution is to install momentary contact switches to turn the motor off at the limits of the elevation travel.

That said (and after working on my Panther), I'm not sure that replacing the clutch is the first place to look if you're having problems of this nature. If the elevation and rotation gearboxes are having trouble doing their job, it may just be a symptom of an underlying problem.

The elevation mechanism should be able to move the barrel easily if the the barrel/recoil mechanism are balanced, and the swivel pins don't have too much friction. If they're balanced, the kit-supplied spring isn't necessary (and may actually contribute to the problem). You can test this by disconnecting the elevation arm and feeling how much work the elevation unit has to do. If it's too barrel heavy, you can add lead weights to the recoil unit. If it doesn't swivel freely, there may be a problem with the way the swivel pins are installed. If it passes these tests, you may have a defective clutch gear.

Similarly, if the turret doesn't rotate smoothly and freely with the rotation gearbox disconnected, the gearbox will have problems dealing with it. The rollers should move freely, and the bottom of the turret shouldn't scrape against the deck. If it's scraping against the deck, larger rollers will give more clearance, and you can buy them at ETO Armor (Bob's very conscientous, works when he should be sleeping, and ships super fast). Larger rollers by themselves may not solve the problem if the deck or turret base are bending due to the weight. Tamiya includes a heavy weight for the rear of the turret that must be installed to achieve a balanced turret, but this may contribute to warpage. In that case, metal braces (square tubing) can be epoxied to the inner surfaces to keep the deck and turret base flat and rigid.

Another possible source of trouble is the wiring that runs between the turret and the hull. Generally speaking, large tight bundles of wires are less flexible than loose strands (i.e., solid core versus stranded wire), and if the bundle is anchored at single points, may make the turret more difficult to turn, as well as concentrating where the wires are repeatedly flexed. Of course, you don't want a chaotic mass of wires either, since those can get jammed in gears and the turret flanges! In either case, it's a good idea to glue/attach the individual wires by their insulation near to where they're soldered, since this acts as a strain relief. When wires break from repetitive movement, it's almost always at the solder joint.

In my case, none of the above were the real problem or solution. In both the elevation and turret rotation gearboxes, the drive was quiet going one direction, but made an annoying ticking sound going the other direction. This was also true of a replacement elevation gearbox I'd bought from Japan. The turret rotation gearbox was tolerable since it's quieter; neither rotation direction demand more of the gearbox since gravity exerts the same force in either direction. The elevation gearbox was another story. Raising the muzzle places more stress on the mechanism, resulting in a louder clicking.

After a long, time-consuming search for solutions, I finally figured out that Tamiya's casting of the worm gear was flawed-- in all three of the gearboxes! The worm gears have imperfections where they should be smooth (which can be confirmed by running your fingernail in the groves). Swapping the motor with one from a Heng Long elevation unit instantly fixed the problem-- no more noise, the elevation travel was smooth and silent in both directions. Arrrgh. Shame on Tamiya and their once-a-decade quality control checks. This would probably disappear with use/wear/filing, but shouldn't be there in the first place. I've written an FYI to Tamiya that they'll probably ignore.

Tamiya King Tiger recoil laser IR emitter

10/22/09- While I had it open... The laser MG mounting is at the upper right and the IR emitter & tube is mounted at the lower right. The laser's wires are taped to the recoil unit since the two move in unison, and you don't want the laser's wires to be stressed at the solder joints. Aligning the laser perfectly with the thin machinegun barrel is a bitch, and since I'm willing to live with imperfection, it produces a small halo near the laser projection point.

Before I'd determined that the elevation motor's worm gear was defective (and replaced with a Heng Long motor & worm gear), I replaced the clutch gear with a simple one (the blue gear) from Tamiya's 6-speed gearbox model kit. This necessitated trimming the gearbox's stop tabs so the arm could rotate 360 degrees and avoid stripping the gears.

The Impact recoil mechanism upgrade's voltage regulator is mounted near the loader's hatch so it can be adjusted from the outside-- it's really a set & forget gadget though, and I didn't spend much time messing with it since I don't have a 1:1 King Tiger to dial in the correct return speed.

 

The Hull Machine Gun: Once I found out that a laser module could be substituted for the machine gun diode in Heng Long tanks (thanks Creeping Death!), I wanted to do that in all my tanks. It's a neat effect that adds play value with few downsides (other than the color, and that WWII tanks didn't have lasers)-- it's fun for humans and cats love to chase it. It also looks great shimmering through smoke. In theory, you could use it as a targeting system, but just like real red laser targeting systems on real guns, they're hard to see outdoors. Despite that, I thought that if the King Tiger was going to be a shooter of invisible IR beams, it would be nice to have the tank shoot something I could see, too.

Unfortunately, it was not to be. I'd tested the LED MG system with 3 volts of battery, replaced the LED with a small laser module, centered it, and tested focus and range -- worked fine. After I finally installed it in the tank and plugged it into the DMD, I learned that the beam would only dimly project maybe an inch beyond the MG barrel! Bummer. I guess that the DMD puts out lower voltage than the Heng Long unit, enough to power the MG LED but not enough to power a 3-volt laser? Darn. I'm not quite ready to investigate and bypass whatever might be causing this (a surface-mount resistor?)...

[09/24/09- Indeed. During my Panther project, I found that shunting R18 boosts the pulsating voltage at CN3 so that a laser can be substituted. However, I decided to keep the LED in the King Tiger because it looked better as a hull-mounted, firing machinegun since the muzzle flash is much more visible from all angles.]

[10/01/09- Laser installed as coaxial machinegun, with servo switch to toggle between it and the hull LED machine gun (as installed in the Panther). I'd initially judged the coax machinegun mounting as a problem since the gun's barrel has to articulate through the turret and be fastened to the small opening in the mantlet. It turned out to be easier than I thought: The Tamiya machinegun barrel is thin: It fits and fastens in the mantlet coax hole with only a little bit of reaming. The laser unit can be aligned so that it projects the beam through the barrel, although it's difficult to align it perfectly-- this appears as an offset halo at the projection point.]

Tamiya King Tiger lights
Laser MG, LED MG, Cannon flash

Tamiya King Tiger volume control Volume Control: One of the best things about the Tamiya tanks is the sound; if you've only heard the stock Heng Long sounds, it will blow you away in both its clarity and loudness. I was amazed that it came from such a small diameter speaker. The sounds themselves are pretty good and utilitarian (sorry, I think human voices mixed in with sound effects sounds really hokey).

The loudness is nice, but indoors, it's a little too much and the small trimmer on the DMD/MF unit is not very accessible. One of the first mods I made was to replace the trimmer with an extension cable and wire a 20k potentiometer. I disguised the pot as one of the round gadgets on the rear deck, and it's been a blessing.

Electrical Connections: It's a given that you're going to be taking your tank apart, over and over and over. It's also a lot easier work on the different sections separately, instead of propping them on their side with wires stretched between them-- that's bad news, and an accident waiting to happen. Ideally, you'd have plug connectors between sections so that you could quickly and easily disconnect the sections. While Tamiya doesn't make it easy to unplug things from its DMD unit, you can take that into consideration and plan for any additions that you make.

For the volume control, I used a 3-pin connector plug/socket wire, which is a lot easier than plugging/unplugging things in the DMD unit. Generally, if the situation allows and there's room, stuff (like receivers & servo switches) should go in the lower hull. That's where all the main electronics are, so wiring can be laid out without being disturbed. Although plugs may not be required, it's still a good idea so that you can remove components. Any electronics installed on the rear panel (like convoy lights) probably should have a connector as well, since you may want to remove that panel to work on the idler, or wheels. Likewise, the front headlight is installed on the upper hull, so that wiring should connect by plug/socket to the main part of the circuit in the lower hull.

The Tamiya connectors are Molex 2.00mm "micro-latch" style, but plugs and sockets are easy to find if you've got broken CD players to scavenge-- some plugs are identical to those that fit Tamiya's DMD. That's useful if you need to grab power from CN5 for running lights (but read my caution, above under "Light Control"!). I have also scavenged some plugs and sockets from Heng Long electronics since they're a different size, which helps distinguish between the wires (It's a good idea to color-code/write on the plugs as well).

Tamiya King Tiger interior

Ahem. Normally, it would open from the other side so that the battery wouldn't be trapped beneath the web of wires, and so that some wires wouldn't have to stretch so far. Yep, it's a mess, but that's just the way it evolved, and the way my mind works: Wires were scrounged from whatever was handy, and I scrounged a lot of Heng Long connectors with the attached oversized wires. Someday when I'm bored, I'll plan it out and make adapter cables to consolidate the connections in fewer multi-pin plugs.

 

Surface Detailing: This is the "model" part of the kit, and I think initially, I was so overwhelmed by the number of parts and focused on the mechanics that I didn't look at the details. Of course, the quality is very good, with clean castings that fit precisely-- Tamiya has a well-earned reputation for that, and that hasn't changed in the bazillion years since I've been in Junior High School. Once I started looking at reference pictures for ideas though, I began to notice how simple a lot of the detailing was: Hatch handles are solid undetailed blocks, front hatches are molded on, the commander's and loader's hatches aren't hinged or articulated. I guess the disappointment is that there's so much more room on a 1:16 scale model than a 1:35 scale model, but they didn't take advantage of it, as Trumpeter has done with their 1:16 model kit. I would have to say that Heng Long tanks have comparable casting quality (on the other hand, Heng Long's Pzkpfw IV commander is clearly a recast copy of Tamiya's, so some of the crisp detail is lost). Heng Long seems to make a better worm gear too...

One could argue that a running RC model needs to be more durable than a static kit, so fragile detail is to be avoided. Opening hatches are cool, but are just one more place for dust to get in to clog the gearbox. Maybe. (There are a zillion other places for dust to get in.) My theory is that the Tamiya kit is very old (I think it was a static model first?), from long before a lot of the newer molding and casting production techniques were developed. They haven't invested much new money in updating this aspect of these older kits.

Aftermarket Parts: There are lots of aftermarket parts to superdetail the Tamiya kits, so you can decide for yourself where to draw the line in the continuum between really cool-looking stuff and what's practical or useful. Certainly, you can spend a lot of money, especially with German import parts.

Most of my first aftermarket purchases were for the performance aspect: wheel ball bearings, Daryl Turner's improved idler design, and drive shaft supports. Metal tracks were a luxury, mainly to satisfy my desire for "heft", which necessitated paying more attention to the drivetrain upgrades. Shortly thereafter, the main gearboxes were replaced with Impact's gearboxes.

Buying aftermarket detailing wasn't as easy: Although it all looked good, almost all of it was expensive and none of it was really necessary. Generally, I selected parts that I thought added something new (the mesh grills) or added improved detail in a highly visible area (machine gun & mount, and to-scale tapered antenna). If it was something I could make (hatch handles), or could accurize (armored exhausts), I'd try making my own before buying. Since there are so many things begging for your money, I try to establish logical rules for selection (even if I break them).

Muzzle brake, antenna mount... Metal is cool, and very tempting. However, these taught me to try to avoid the temptation to replace plastic parts with metal, "just because", unless there was a structural benefit or for superior detail. The aluminum muzzle brake wasn't significantly better than the plastic one when the plastic one is finished without seams... plus the plastic one is lighter, easier to paint, and easier on the gun elevation unit. Similarly, I bought a metal antenna base that appeared to be no more detailed than the plastic one, just heavier. I did replace the antenna with a more realistic (and dangerously sharp!) aftermarket one because the tank didn't need a functional external antenna with a DX6 receiver. Basically, it looked better than the antenna Tamiya included. (However, I later configured the tank as a command tank, and used the metal antenna mount, removed the aftermarket antenna and altered the original Tamiya one so that it could be quickly detached. Antennas are annoying when you need to take apart your tank.) For that matter, I ended up using the aluminum muzzle brake too, despite my arguments, just becuz... Heck, it's METAL.

The Headlight... This is an either/or. The metal headlight does confer a structural benefit over a plastic one, since the plastic post drilled through for wiring is relatively weak. Also, a bright LED is probably more likely to shine through the plastic than through metal. I believe that the metal one does have better detailing too, if you want to spend the bucks on it.

Hatches... Metal hatches are often used when you want to add an opening hatch feature, though in some cases it might be "just because", especially if they have superior detailing. For me, the main reason to get them would be so that I wouldn't have to worry about destroying the plastic ones or surrounding detail when I cut them out. (Another reason would be if they had particularly tricky hinges, like the front hatches on a Tiger 1.) I didn't find any metal versions of the King Tiger front hatches, so I had to be careful where I cut, knowing that I'd have to patch any damaged surfaces afterwards. Fortunately, the hinges on the King Tiger are simple.

Tools & Accessories... Metal tools and accessories are better looking than sculpted-on detail because they're separate with proper space between the part and the attachment surface. However, the plastic ones may look just as good if they're separate parts and finished properly. (That said, Wecohe makes a really cool working bolt cutter with real wooden handles!) If you decide to use photoetched fasteners, it's probably easier to remove molded-on fasteners from plastic than metal.

Track Hangers... At first, I thought that this was an unnecessary expense, since the included plastic track links with sculpted hangers were more durable and less "fiddly". As I wrestled with the issue of my late King Tiger metal tracks, I wanted the option to change the turret-mounted track links to match the shoes the tank was wearing. I'm not really fanatical about historical accuracy (in fact, I'm using the 9-tooth sprockets with the late war tracks since I believe that they work better), but I thought that matching the two was an issue of consistency. That being the case, I wanted the metal track hangers. It would be relatively easy to fabricate the parts in styrene, but being thin and small parts, they would be very fragile, and in a location that begged for them to be snapped off. In another snub of historical accuracy, I installed 2 sets of track hangers in each turret corner, instead of the 3 (one for each single link) that a historically correct late King Tiger (sitting in an abandoned factory, unassembled) would have.

Photo Etched detail... Some of the photo-etched detailing is very tempting; we're talking about brass fenders and latches for tools and cables with working wingnuts! For me, this level of detailing represents the line in the sand between a kit that you won't be afraid to run (and damage) and a display model that's occasionally run, but very carefully. This level of detail represents a supreme challenge for the modeler, which may be your primary focus in this hobby: You can always buy a couple of beaters to play rough with.

I chose a middle-of-the-road path (mainly because that was what I could afford!); although I like the idea of detailing with wingnuts, I could see breaking that stuff off or squashing it accidently from handling the tank, no matter how careful I was. Similarly, the brass fenders were very tempting, but I thought they'd be too fragile and easy to bend (which would make them more accurate). The plastic ones are durable and don't look too bad if attached with dozens of hex-head screws instead of the functional regular screws as Tamiya intended.

Rear mudflaps... I'm undecided about the rear mudflaps. The included plastic ones are durable, except for the hinge area. Because of the way they fasten, the hinge area is vulnerable to breakage if one isn't careful where one grabs. Strengthening one area (metal hinge pins) just transfers the vulnerability somewhere else (the hinge arms). I haven't seen any cast metal mudflaps for the King Tiger, but I have seen folks assemble them from photo-etched kits. This part might work better in brass, because brass bends rather than breaks, but they look awfully fragile. Another idea I've had is to make the hinge pins out of elastic thread; the idea is that the "pin" would stretch and bend, but restore to its original shape. [I later refined this concept, discussed here.]

Front drive supports... These are the things at the front of the tank, right in front of the drive sprocket. I first thought that these were strictly for metal fetishists, but once I'd started running the tank, I realized that they had a less-obvious practical purpose. This part secures the upper and lower hull at the front: the upper section slides forward into the side tabs. With the stock parts, there's enough play on the sides for one end or another to slip out. Impact's metal part is cast with simulated weld marks, which in effect widens the side tabs so that the upper section can't slip out as easily.

Do it yourself... Reference materials may point you to some detailing tweaks and fixes that aren't offered as aftermarket kits, or are priced outside of your comfort zone-- this motivates you to do on your own. These would be things like adding zimmerit, cast metal texture & weld seams, correcting inaccurately placed details, making and applying minor detail. This kind of stuff can be fun or tedious, but the admission fee for putty, brass strips and Evergreen styrene is relatively cheap.

THE DRIVING TEST

If you're like me, you can't resist taking test drives several times during the build, since it's wise to test stuff as you build to make sure that it works-- it may save you the time and trouble of backtracking. Eventually you finish though, and it's time to move on. Before signing off on the mechanical-electrical stuff to begin painting, I wanted to do a final DMD calibration. This is where you press a button on the DMD that puts it into calibration mode, and then you move the transmitter's joysticks so that the DMD will know what the limits are.

I have two bits of very important advice: 1) Make sure that you press the correct button before you start moving the joysticks, or better yet, 2) Make sure that the tank is on the floor or on a suspension support, and not tracks-down on a table. I'm sure that I don't have to spell out what might happen to your two-weeks worth of tweaking if you don't. Arrrrrgh.

Mine landed sprocket-first on the carpet. Miraculously, not a single crack in the plastic, but a few parts that I'd loosely tacked on had flown off. The gearbox driveshaft on the other hand, didn't fare as well. Even though the shaft appeared to be thick and robust, 10+ lbs driven into ground was enough to bend it beyond repair and fracture the metal. Very depressing. So the formal driving test was postponed, awaiting the arrival of a new Impact gearbox. Although it may sound like sour grapes, I'd been thinking about getting Impact's gearbox because the stock Tamiya one ran too fast-- this just forced the issue!

Impact's Gearbox (AKA "TU" or Transmission Unit): For running metal tracks, these seem to be the ones that everyone swears by. They have steel gears (Tamiya's gearbox is pretty slick, but has a couple of plastic gears) and come with the option to reduce the speed (with more torque) by adding an included "Drop Down Gear" & motor mount spacer. If you want to fine tune the speed/torque combination, Impact makes a variety of hop-up gears. Although the gearboxes are initally very noisy, they do quiet down somewhat with use, after you break them in. It's important to check that your pinion gear meshes well with the Drop Down Gear-- that's not a given, and I had to lengthen the motor mounting holes to give just a little more adjustment range to tighten the gear mesh. The biggest benefit is that the tank runs at a more realistic speed than it does with Tamiya's Indy 500 gearbox. It makes the tank more driveable and controllable.

A few words about metal tracks & driveability: Daryl Turner, an aftermarket parts designer, strongly hints in his adjustable idler upgrade instructions that plastic tracks work very well. Hint, hint. Once you add metal tracks, the tank suddenly becomes much more demanding. Firstly, the tank gains a lot of weight, and this puts more strain on the drivetrain, more wear on the gearbox, more load on the torsion bars, etc. Secondly, the idler needs much more tension to pull the heavy tracks taught, so that they don't droop too much and create too much slack. The proper idler tension is a balancing act: Some "give" is needed so that pebbles and twigs don't easily jam the tracks, but too much and excess track may accumulate at a sprocket when you turn on challenging terrain. If this should happen, the track may either skip or come off the sprocket. If the idler is set very stiff, there's less chance of that happening, but it's hard on the drive and idler shafts since you're essentially pulling them together with a metal chain. That said, if you insist on running metal tracks (they're hard to resist), you should beef up all the other parts involved.

THE BATTLE UNIT TEST

The battle unit (Infrared emitter and detector) is available separately as an option (meaning, you pay extra for it), and unleashes a major part of the functionality that's built into the King Tiger's electronics. I really don't have much to say about my experience with it-- it works as it should, like a Lasertag system. I first tested it in its own built-in test mode (detects shots from its own IR emitter). I tested it with my Heng Long Pzkpfw IV which I'd equipped with a Tamiya-compatible DBC/DBU circuit. Thankfully, both systems worked as expected, and it was rewarding to hear the extra sounds and witness the additional "behavior". I still think the IR battle system is a little too "virtual" for my tastes-- I prefer witnessing simple cause and effect, like shooting projectiles and seeing where they hit. On the other hand, trying to hit a small target with a pellet, remotely and without a first-person view, is a ridiculous and potentially dangerous idea. The fact is, IR's wide beam is more practical for third-person view RC tank battles. (God made guns with sights for a damned good reason.)

I spent a lot of time mulling over where and how I was going to mount the battle system. If you like modding stuff, there's a real strong urge to conceal the emitter and detectors within the tank, instead of doing it by the book with the dorky detector mushroom poking up from the turret. Tamiya gives you parts to clip the emitter onto the barrel, which doesn't look great and is likely to scuff the barrel's paint.

Tamiya King Tiger Battle Unit
IR Detectors, left-right: Impact, Tamiya, Darkith (DBU), ElMod (with parts from Heng Long HBU).
Impact & Tamiya appear to be identical, but have slightly different and incompatible bases. The stock ElMod apple is a naked circuit board tower with 4 IR detectors (versus Tamiya's single detector with inverted 4-sided pyramid mirror); it has 10 pins versus the Tamiya's 5 pins. The DBU uses a standard computer DB9 plug.
I decided to mount the detector the conventional way by using the mushroom/"apple" tower. This is really just to conform to the IR battle mode standards, for the benefit of others. The detectors reject hits at particular orientations, so I don't think a cleverly-disguised installation, no matter how well done, could be counted on to meet the standards for fair competition. The tower unit plugs in quickly and easily, so the tank doesn't have to suffer from wearing it except when it's battling.

The emitter is a bit different. Clipping it on the barrel or in the barrel mantlet would seem to give you the benefit of the gun elevation control. I ruled out the barrel clip method because it looked funky, because of the likely scuffing of the barrel paint, and also because Tamiya hadn't provided a quick and easy way to plug the emitter into the turret, for a temporary setup. Unfortunately, the coaxial machine gun port on the mantlet isn't ideal for mounting the emitter-- not enough room for a 10+mm tube without mangling the cosmetics. (I've read that for fairness and standardization, the emitter LED should be mounted 10mm in from an opening in its mounting tube.) The most likely place to permanently mount the emitter seemed to be through the viewing port on the mantlet. Although this wouldn't track with the barrel's elevation and there would be a blind spot from being next to the barrel, IR beams fan out in a conical pattern, so the fixed elevation and blind spot wouldn't be much of a disadvantage at greater than point-blank range. I also had to give the tube more of an oval cross-section to fit the shape of the viewing port. Not ideal, but I didn't want to sacrifice the cosmetics.

DRESSING HER UP

At last, the paint job, the final phase! The paint scheme sat at the back of my mind throughout the build, as I searched for references and ideas. It influences decisions you make about what details to add. As the build is progressing you can waffle about, but after you've completed all the main stuff and tested the tank's functions, you're forced to commit to a specific paint job. It's the last step before you can get on with your life.

This usually goes hand-in-hand with thoughts about your King Tiger's timestamp. The King Tiger had a remarkably short lifespan, but each few months of production witnessed an evolution driven by many factors, including improvements, policy changes, material shortages and the progress of the war.

I think the most obvious approach to take is to accurately depict a specific, known King Tiger from a specific period of time. Tamiya gives you decals and paint references for four numbered King Tigers. Tank museums have displays of the few surviving tanks, some of which have been documented online with very good close-up photos. This approach can be very challenging and rewarding from a technical perspective, and it takes a lot of research and skill to do a good job. If you don't want to draw corrective comments from "rivet counter" armor fans, this is probably the safest approach to take. (Well, now that I think about it, maybe not!)

I don't believe that most RC tank modelers take this approach though, but instead, prefer to individualize their tanks with a mixture of research and personal preference. I think that for many folks, a historically plausible rendition is good enough. Fortunately, the policy nazis aren't walking around to enforce regulations, so we can do whatever we want with our tanks. If we get tired of a paint scheme, we can always change it.

I wrestled with this issue a lot, mainly because of my personal preferences. At the outset of this project, I wasn't fond of the ubiquitous dark yellow/red-brown/olive green paint scheme. I liked it even less with the "Ambush pattern" dots. I looked at reference paint schemes and never found one that was The One for me (I was disappointed that the Germans didn't paint them solid Dunkelgrau.); the yellow and brown scheme from Tamiya's reference flyer was probably closest to being aligned with my aesthetic sensibilities. Unfortunately, it had Zimmerit, and mine didn't. (Most King Tigers had Zimmerit since it was applied at the factory until they were ordered not to do it.) Another thing: My King Tiger was going to have a Balkan Cross on the turret, along with big numbers (but not blue or yellow numbers). Yep, personal preferences can seem totally arbitrary. (I also had an impulse to do something really unique and artsy: Paint the tank in monochromatic black, white, & gray, like the actual WWII reference photos.)

Another consideration was purely practical. Unlike static models, RC tanks get used. Paint gets scraped and rubbed off from handling and running into things. Since the model was cast in yellow plastic, I wanted to use that as the base color, and minimize using other colors in areas that were likely to be worn, like under the turret rotation, or along the front plate sides where the hull sections slide into each other. Of course, there's the historically correct usage of primer colors to contend with, so that would tend to hem you in, if you let it.

As you can see, I did have some desire to dress my tank in a historically plausible manner... but I wasn't willing to let that to be the only consideration. The turning point came fairly early, when I got the late war single link tracks with 18-tooth sprockets, mentioned earlier. I preferred the way the tracks ran with the original 9-tooth sprockets, so any hope of historical accuracy went out the window. The track hangers were arranged for pairs of single link tracks, unlike the single link 3 x 2 x 2 arrangement on a true late war King Tiger. I decided to include the jack and wooden jack platform on the rear (because they came with the kit!)-- characteristics of earlier King Tigers. Once you've crossed the line, you might as well do what you like.

I used Tamiya's Armor Sand spray paint for the base coat since it closely matched the cast plastic color. I initially wanted to spray the camouflage colors using Tamiya's spray lacquer since I thought it would be more durable. This would dictate making a sharp-edged camouflage pattern since spray cans don't have a fine level of spray control without resorting to oddball feathered masking schemes. I then discovered that I didn't have a suitable shade of brown in spray paint... but I did have it and related shades in a bottles of acrylic. So this meant that I would have to use the dreaded airbrush (I typically drop a filled color cup at least once a session, and this time was no exception).

After applying the red-brown markings, I stopped to assess it and thought, "Ennnyyyyhhhh... what if I added olive green?" When it was all done, I realized that I'd ended up using the colors that I originally didn't think much of, but was now somewhat okay with. It doesn't look much like the mid/late war ambush pattern, which is primarily green, but that would have been hard to achieve given my intent to leave as much yellow as possible. There are areas where I think I should have put deeper, stronger, and larger patterns of shading, but it doesn't bother me enough to go back and redo it. I haven't seen other King Tiger paint jobs quite like this, so I assume that it's historically wrong.

I tried to do a watercolor filter as demonstrated on the DAK website, but quickly got frustrated with the amount of work required to eliminate the beading. I'm impatient and work better with acrylics... thinning, brushing, smearing and feathering with my fingers. Basically, I tried not to let it pool and dry, to eliminate most of the telltale rings. The dirtying-up continued with fake chipping, rust and dust, so any pooling that got overlooked disappeared into the ugly mess.

I wanted to make my own decals, but options are fairly limited if you don't have a printer that prints white. (My old Alps MD5000 was acting up, and is in mothballs now.) The white decal paper helps in some situations (like making the Balkan Cross), but really isn't ideal for making numbers with closed loops-- requires too much precise cutting of the decal. After mulling over my possibilities (buy decals?), I decided to use those that Tamiya had included, with some minor rearranging of the numbers: "300" became "003", which my meager research indicated was some kind of command tank. It seemed to be a more generic type of number, rather than a specific tank number. Maybe?

At any rate, if it were some kind of command tank, I felt obliged to add decorations so it could play the part-- the star antenna at the rear, and moving the hull antenna to the turret. The 6-sided antenna was frustrating to make since I couldn't get solder to adhere very uniformly or controllably. I finally bought Wecohe's, which is a very fragile photo-etched kit.

THE LAST WORDS

However you dress her up, it's all fun-- or should be! Building a Tamiya RC tank isn't a quick job, between getting ideas and waiting for parts to arrive. A straight build could probably be done in about 3-4 days; mine took about 4 weeks to get to where it was mostly finished (but I'm still doing stuff to it). With RC tanks, it's all part of the process.

I have to admit that being "done" is a bit sad; but you can't dwell forever on a dwindling list of fixes, and eventually have to move on. Well, sort of. You can revisit the build to add new things. Since "finishing" my King Tiger, I've added a Turnigy Speed Control, which connects between the receiver and the throttle channel and slowly raises or lowers the speed in response to stick movements-- it simulates the momentum of a heavy tank. I've also added Impact's Recoil modification, which makes the recoil operate more realistically. The motors were replaced with Graupner Speed 400s (7.2 volts), mainly because I bought spares when I bought them for my Heng Long Tiger. I also replaced Dragon's Joachim Peiper figure (first pic on page) with a slightly modded Heng Long tank driver; after putting a 120mm Verlinden figure in my Panther, Herr Peiper looked miniscule in the King Tiger. (The new driver is kind of a running joke...)

Tamiya King Tiger figure

A word of warning is in order if you haven't been bitten by the bug: This stuff is addictive! As the project wound down, I found myself Googling other Tamiya RC tanks, looking for my next fix.

Resources: For ideas, Google is your friend. There are many pictures of King Tiger builds, but Masa Narita's website is one of the most helpful sources for ideas, with lots of good tips and pictures. The result is a beautiful, super-detailed build.

Tamiya King Tiger

Tamiya King Tiger

Tamiya King Tiger

Tamiya King Tiger

"Hey, your Tank Commander's Uniform Has Breasts!": Of course it does; it's double-breasted.(For what it's worth, the tread directions were later reversed on this and the Panther after looking at a bunch of pictures. I sure hope they got it right!)

 

 

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