Tamiya DF-03 MS Project

Page 1: Assembly

This is what waited for me at the post office when the package finally arrived from Germany. The photos don't do it justice. The box was at least twice its normal weight from being so saturated with water. In order to have become this wet and damaged, I suspect the box must have been nearly submerged for a considerable period of time, then dropped or crushed while wet. How they managed such a thing is a mystery.

Here's what I found inside once the wet cardboard was peeled away. The right hand end of the box is almost normal, but the left end is soggy and crushed. You'll also note that there is a significant tear in the lower edge, so I had some concern that parts had been lost. Luckily Tamiya individually bags all their parts trees and the hardware bags should be big enough to remain inside.

If I was hoping for a nice picture of the model to hang on the wall or save for posterity, I didn't get it here. My beautiful "limited edition" box card doesn't look so good. This shows the state of the label on the end of the box. The picture on the right shows the remnants of the packaging after I removed the contents.

The instruction manual had pretty bad water damage so I opened it to each page and let it dry with a flat weight on top. This did a reasonable job. The manual is now usable but certainly not pristine. My biggest concern was the stickers. These are unique to this set and rare so I could not reasonably expect to replace them. Tamiya bags the stickers so they didn't get wet, but the sheet was badly crinkled as shown.

Here are all the parts arrayed on the table. The plastic bags saved the parts and the hardware, so miraculously there was really no discernible damage to any of the parts. This is a reasonably complex kit with a lot of sprues and many hardware bags as shown.

The build begins with the construction of the rear ball differential. The center carrier houses 10ea 3mm balls which ride against hardened raceways and are clamped through a compression spring. There is a thrust bearing in series with the spring to prevent the screw from loosening as the diff rotates. This thrust bearing has a central swaged collar to hold it together so it doesn't need to be assembled. Huge 10x15mm bearings support the hardened drive cups. This is the same differential found on the basic DF-03.

The rear differential assembly inserts from the rear rather than from above like a normal build. This makes it easy to remove the differential for maintenance without taking apart the whole rear suspension.

These pictures show the transmission gear assemblies in an exploded and assembled view. The lower part in the center column is a one-way bearing, unique to the MS version, which allows the front wheels to freewheel when braking. The longest steel shaft on the far right will connect to the slipper clutch and drive the whole transmission from the motor side. The bevel gears connect to the prop shaft and run to the front end.

Here we see the orientation of the various gears inside the rear transmission. Torque will enter at the large steel shaft, enter the aluminum spur gear, transfer to the nylon idler, and then drive the large spur of the differential. The bevel gears connect to the prop shaft in parallel. The whole gearbox is very compact and takes up very little room.

The aluminum motor mount plate can now be attached to the gearbox. The blue cylindrical heat sinks are extra parts included in the MS kit. There is a 3rd heat sink hidden beneath the black bracket.

The MS kit comes with a slipper clutch which can be built with any of 3 spur gears: 78T, 82T, or 85T. It is interesting to note that apparently they are not all made of the same material. I used the smallest gear to give me the highest top speed. This slipper has two friction disks.

I decided to use a 23T Super Stock BZ motor which will make this nice and fast. This chassis uses unusual gears. The pitch is 0.5 module and pinion is made from steel. Both of these are hardly ever seen on Tamiya models. Almost all Tamiya kits come with aluminum pinions, but in the case of the DF-03 it is steel even in the standard version. 0.6 module is usually used on newer buggies and cars, 0.8 module is used on older buggies and trucks, and 0.4 module is used on racing touring cars. 0.8mod is compatible with 32p, 0.4mod is compatible with 64p, and 0.6mod doesn't have an imperial equivalent. This odd 0.5mod pitch would be 50.8p, so it is not close enough to 48p to work together but close enough to easily get them confused if you had them in a box together. Why was the usual 0.6mod not good enough? Perhaps it is intentionally incompatible with the DF-02 (for example) to avoid exchanging parts which should not be exchanged.

The gear cover includes a removable plug to access the adjustment nut for the slipper clutch. The rear shock tower is plastic and attaches to the gearbox. The Christmas tree you see is the rear body post. The DF-03 is the only chassis I've seen which used a ribbed post. You remove the appropriate number of ribs to support the body you are using.

The lower suspension arms connect to the gearbox with straight pins and E-clips. The upper arms are hardened turnbuckles as opposed to the threaded rods of the standard kit. The axles are steel universal type as shown on the right versus the dogbones of the standard kit.

The rear uprights have three hole choices for the upper ball joint connection. The center is used by default. The entire rear suspension module can then be connected to the chassis tub as shown.

The front ball differential goes together just like the rear and then sits inside the front gearbox housing as shown. The front joint cup on the MS model is an upgraded aluminum part. The gearbox housings are shaped to very closely match the contour of the gears and minimize space and material used.

The front molded shock tower is very thick and sturdy. There are 3 locations to attach the upper end of the shocks and at least 5 possible locations to attach the upper suspension arms. There are an additional 3 holes between that are of questionable utility.

The dual bellcrank steering uses 8x5 bushings. I chose not to upgrade these to bearings in this particular application since the amount of rotation is minimal. The aluminum prop shaft needs to be installed at the same time as the front bulkhead.

The front suspension goes together very much like the rear with wishbone lower arms, turnbuckle upper arms, and lower shafts with E-clips.

Whereas the standard kit uses front dogbones, the MS version uses CVD universal axles which offer smoother power delivery at large steering angles. The steering links are also turnbuckles.

The single most valuable upgrade that is included in the MS kit is the set of aluminum dampers shown here. I've previously shown how to build these dampers on my page for the DT-02 MS, though these springs appear to be a coarser pitch. With the shocks installed, the rolling chassis is essentially done. Note the very long blue turnbuckle rod connecting to the steering servo. This kit also comes with the high torque servo saver.

On the DF-03 chassis the battery installs from the bottom. The access is through a large plastic hatch which is retained with a cross pin. This pin is usually plastic, but the MS kit comes with the aluminum pin shown. The picture on the right shows all the electronics installed along with the battery.

The MS kit came with both the original Dark Impact wing as well an optional TRF wing. Naturally I chose to use the TRF option. The body is actually the same one used on the Dark Impact, but the paint scheme will be very different. The picture on the right shows a test fit of the body and wing after trimming.

The regular Dark Impact covers the windows with stickers to there is no need for window masks. Due to that unfortunate fact, no window masks exist for this body so I had to mask them manually as shown on the left. I just applied a large piece of tape and then cut around it with a sharp knife. On the right you can see how I've masked off the front area which will become white. The exact location of the mark line is not that important because it will be covered by stickers.

Here I've painted the metallic blue, backed it with silver, removed the front masks, painted the white, removed the window masks, and applied the smoke tinting. Doesn't look all that impressive given how many steps it took. On the right the full set of stickers has been applied. This was very difficult because the complex patterns need to intersect exactly at the sticker boundaries or it looks terrible. The fact that many of the stickers were crumpled in shipping made it even harder. I think it came out looking pretty good, all things considered.

The wing also required two colors and masking. If you look closely, you will even note that the trailing edge remained clear. The wing needs to be painted on the same side as the overspray film which means it needs to be removed and then the opposite side masked manually. The completed buggy is shown on the right including the Dual Block tires I added in competition compound.

These images show my whole collection of MS cars including (from left to right): TT-02B MS, DT-02 MS, and DF-03 MS.

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