Preparation - Before we get down and dirty...

Reference Book

While waiting to gain full access to the Armortek Owners' Forum, which can be read by anyone, mention was made of an illustrated book on the Sd.Kfz.7, imaginatively titled "Sd.Kfz.7 in detail" by Frantisek Koran et al, from Wings & Wheels Publications (obtainable from Landmark Military Books). Light on text, it's crammed with colour photos of several museum pieces in various stages of restoration, including examples of the Flak 18/36/37 guns they carried. Early and late variants are shown in quite some close detail. This book is excellent source material for the modeller wishing to super-detail, or just to see where Armortek have necessarily had to compromise on total authenticity for technical or financial reasons. cover page
Some facts to pass on: © 2006, WWP
  1. The Sd.Kfz half-track was first developed in the early 1930's. By 1934, the Type 7 (8 tonnes) was in production. Several variants were introduced until production ceased in 1944.
  2. The Armortek model is an early variant (late variants can be distinguished by the angled track guard over the drive sprocket, as on the book cover)
  3. "Sd.Kfz." is short for Sonderkraftfahrzeug - German for 'special motor vehicle'. This was to get around the restriction on military developments placed on Germany by the Allies after WW1.
  4. The majority - but by no means all - were built by Krauss-Maffei AG, who also did the development.

Option Pack 1

Option Pack 1Before starting on the model proper, I decided to check out the drive option pack (OP1). This comes with its own instruction booklet and it's all straightforward to connect together. OP1 consists of:

The user needs to add their own transmitter and receiver (6-channel is recommended, though 4-channel will suffice for controlling OP1 kit only), receiver 6V battery pack plus two 12V lead-acid gel cell batteries - 7Ah are suggested. The photo shows OP1 all connected together. Click on the photo to see a bigger one with the components labelled. (Other photos with thick borders like this one - on this and other pages - can also be clicked on to see larger versions. If nothing happens, check you have JavaScript enabled in your browser.)

The Armortek tanks can take much larger capacity batteries, but there isn't room for anything bigger in the half-track. Some builders report that they've installed their batteries under the bonnet instead of with the electronics in the 'boot'. The advantages are that the weight over the front wheels aids steering and they are easier to access for charging or to replace. The disadvantage is the need for longer power cables which need to be adequate or will cause a voltage drop under load. I think I'll follow this option.

If you're not sure which Tx stick controls what Rx output channel, first hookup the Rx battery to the control box, and then the box to the Rx power-in socket. Be careful, the supplied plugs are generic and have no location tag. Plug the steering servo into channel 1, switch on and see which stick moves the servo. (If none do, you've got a basic Tx/Rx problem!). Repeat for all channels and make a note of which stick controls which channel.

Once everything is connected - except the main drive batteries - recheck all connections, particularly the power cable polarities and that the plugs to the receiver are the right way round. Double-check when connecting the main batteries as the spade connectors have no polarity safety-net. Switch on the transmitter first, then the control box. Check which stick does what - you may wish to swap channels over (switch off the control box first!). In particular, there is no guidance on which channels the two cables to the DMR-203 mixer unit should be connected to. In my set-up, Input 1 is CH4 (track steering) and Input 2 is CH3 (F/R speed). (You did follow the instructions and set the DMR-203 internal jumper to 'mix' mode, didn't you? 'Tank' mode, the factory default setting, is where one left stick controls the left track and right stick the right track.)

I decided to have track forward/reverse and track steer on the left stick (CH3+4) and wheel steer and winch in/out on the right stick (CH2+1). CH5 will be used for a future option pack (e.g. smoke unit), and CH6 maybe to control working headlights. YMMV.

While we're on the electrical bits, here's a tip: label everything now, before disconnecting the kit. I've used Dymo tape labels, but coloured electrical insulation tape and fine marker pen will do just as well.

LH & RH motor power and control cables are labelled with red & blue tape, respectively. (This is following boating conventions except I didn't have any green tape, so blue had to do!. If you can't remember which is which, "Red for Right is Wrong" or "We Left Port with Red wine".)

Rx cables are labelled with the channel to which they belong. Further, I always paint the plugs and sockets white on the signal cable side especially when the plugs are not keyed, as here. Then there is much less chance of inadvertently plugging cables in the wrong way in a tight, dark space, which may easily damage the Rx or servo.
Note that the 'Ign' (Ignition) socket has a jumper installed by default. I'm toying with the idea of connecting a small switch on the dashboard to this socket as an easily accessible 'emergency motor kill' device.

Tools

Tools The manual suggests a set of basic tools that are all that is needed to build this model. To this I would recommend a Dremel (a high-speed drill with various attachments) and a set of miniature socket spanners, which are quicker to tighten or loosen the hex-headed bolts than using a spanner. Funnily enough, I found that a 7/32" fitted the M3 hex heads best, and the 9/32" the M4 heads. A 5.5mm spanner fits the M3 hex nuts. A 2mm hex wrench fits the M3 socket screws and a 2.5mm the M4 socket heads.

I also use a wire brush (old suede shoe brush) to clean off the metal parts before painting, and an old toothbrush to get dust and filings out of the corners. The standard drill is used for jobs where the Dremel collets are too small to hold the bit shank. A scalpel or small craft knife (not shown) can be useful for cleaning up non-metallic parts, or to remove excess glue. 

The superglue (cyanoacrylate - thick variety) is used where the manual specifies the use of 'Locktite', and I also give all screw threads a small dab before final tightening down, so they'll never shake loose but will still come off with deliberate attention. A two-part epoxy (10-minute variety that comes in a double-barrelled syringe, not shown) is used to fix the rubber tyres to their wheels.

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