Turnip builds a TA-02

[TurnipJF 9192]

Today I made a start on my Coronapocalypse TA-02 build. Initially it was going to be an Apollo 13 style bitsa, but going through the stash of spares acquired for my DF-01 and FF-01, I came across enough to form the basis of a TA-02 - a car that I have been considering for my fleet for a while now after having worked on the lovely TA-01 belonging to @Jason1145. So with a few more parts having arrived (mostly from Tony, none from model_build) I am building it pretty much as the designers intended. (Although not in the sequence indicated in the manual.)

My initial ponderings were leaning towards a touring or GT-style build, but in the run-up to full lockdown I was considering different race formats that would be compatible with the social distancing recommendations in place at the time. With its lack of a driver's stand, self-marshalling, large open-air course permitting people to remain physically separated, etc, RC rallying seemed the natural choice. Watching videos of RC rally events showed the venerable TA-02 to be surprisingly capable against modern rally-oriented chassis, and since I already have several TC- and GT-bodied cars in my fleet, I reckoned it was time that my lone rally car had a companion.

So here goes: my build of a mildly hopped-up TA-02 rally car begins!

[TurnipJF 9192]

First order of business was to go through my box of miscellaneous fasteners and find the screws and connectors needed for the build. The screws were easy enough to find, being mostly 3X10mm self-tappers, and I found plenty of brass ball connectors too, but these were in varying shades of tarnish, so I spun them up in my Dremel and gave them all a polishing to impart a uniform appearance. 

They will no doubt all tarnish again over time, but at least they can now do so uniformly.

[TurnipJF 9192]

Next up, the rear diff:

In stock form the TA-02 uses a ball diff at the rear, but I am going for a gear diff instead, slowed with AW grease for greater consistency and less maintenance.

The assembly is simple enough, using the same metal innards as found in everything from a TL-01 to a TT-01. Three small screws keep the diff cover on, and the outdrives slide in on their splines.

The whole thing then slides into the rear gearbox moulding from the back, along with the bearings (rubber sealed in this case as befitting a car to be used in the dirt) and it is kept in place with a cap and four standard 3X10mm screws.

The gearbox cases were bought for this build, and I had a choice of red, black, grey or blue. I decided to keep it traditional and go for red. I will be performing the bolt-through mod to help prolong the life of this piece.

[TurnipJF 9192]

Much the same story at the front, but the diff and bearings go in from below. 

Again four standard screws secure the cap.

 

[TurnipJF 9192]

The rest of the gubbins go in from the top. 

The observant amongst you will notice the input shaft for the hardened steel propshaft. I thought a genuine Tamiya one would be nice.

The super-observant will also notice that I have drilled out the first millimeter of the screw hole closest to the camera to 3mm. This relieves stress from the edge of the screw hole, reducing the risk of cracking.

[TurnipJF 9192]

With a light smear of grease around the lip to help keep dust at bay, the front gearbox cover goes on with three screws. 

 

[TurnipJF 9192]

Two screws secure the front shock tower. 

 

[TurnipJF 9192]

I then turned my attention to the chassis tub, adding the mechanism deck. 

 

[TurnipJF 9192]

Then came the ballraced alloy steering rack. I chose a black one so as to keep with the red and black colour scheme that makes this chassis range stand out in my mind. It comes with 850 size metal shielded bearings, which I swapped for rubber sealed ones.

This is a bit fiddly to fit, as if you just put it together and tighten everything up, it binds and won't steer at all. The little drag link screws need to have threadlock placed on their tips, then one needs to slide them through the arms and bushings and screw them into the drag link, carefully adjusting them so that they don't bind but don't have excess slop either. Once the threadlock has set, the big screws that go through the main bearings and their spacers to attach the rack to the chassis can be added. They thread into the plastic tub so no threadlock is required, but again careful adjustment is needed so that the bearings aren't sloppy but don't bind.

Once installed and adjusted though, it is a good, sturdy setup, far smoother and less sloppy than the stock plastic arms and bent wire drag link. I use similar sets on my DF-01 and FF-01, both of which have held up well to use.

 

[Jonathon Gillham 4606]

Looking good. Who makes the alloy steering rack? Thats probably a good upgarde for the Top Force too

[TurnipJF 9192]

Just now, Jonathon Gillham said:

Looking good. Who makes the alloy steering rack? Thats probably a good upgarde for the Top Force too

GPM make a relatively nicely-finished version, Jazrider do one that is functionally the same but typically not as well-finished. Yeah Racing also do one, but it uses a bent wire drag link so doesn't provide as much of an improvement over the stock version.

[TurnipJF 9192]

With the steering rack in place, the front gearbox can be attached to the chassis. 

You can see that I have also attached ball connectors to the shock tower. If this was to be a standard touring car, I would probably have used standard 5mm ball connectors with integral 3mm threaded shafts, but as this is going to be a rally car that will have to take jumps in its stride, I instead drilled the holes in the shock tower standoffs out to 3mm and ran machine screws through them from behind, attaching 5mm ball nuts to the ends. This reinforces the standoffs, making them less likely to crack or snap off when subjected to stresses that the designers may not have had in mind for them.

[TurnipJF 9192]

And this is where we conclude for today.

More to come tomorrow!

[TurnipJF 9192]

With the front gearbox finished and attached, I thought I might do the same at the rear. 

An all-plastic gearset rides on more rubber sealed bearings. 

[TurnipJF 9192]

The cover is attached with the bolt-through mod.

 

[TurnipJF 9192]

The rear gearbox was then attached to the chassis, capturing the hardened steel propshaft.

 

[TurnipJF 9192]

With suspension arms added, it is starting to look very much like a chassis. 

And this is where we once again take a break, in part because I am still awaiting the arrival of the C parts that I ordered almost a week ago from SK Models, and also because I need to give my TT-01 rally car a brushless upgrade in order to free up the brushed motor that I want to use in this build. 

[TurnipJF 9192]

And here we have it, a "LRP TC Special 2" 18X2 brushed motor, fitted with a 18t steel pinion and Pargu alloy motor mount, ready for installation. 

An odd quirk with the Pargu mount is that the mounting holes for the motor are not quite in sync with the stock plastic part. So if I had mounted the motor using the holes usually reserved for a 18t pinion on the stock piece, the mesh would have been too tight. However using the holes usually used for a 19t pinion provides a great mesh. 

[TurnipJF 9192]

In place:

 

[TurnipJF 9192]

Still no sign of the C parts that I ordered over a week ago, and SK Models just say "wait a bit longer" when chased up, so I am running out of things to do. Still, I am determined not to let the Coronapocalypse blues set in, so I distracted myself by making a blanking plate for the switch mounting holes as the ESC I plan on using has one of those pushbutton switches that don't fit the normal mount.

I also shortened some 6mm bushing tubes to 5mm so as to be able to fit the rear shocks.

 

[TurnipJF 9192]

The C parts arrived eventually, so I could fit the uprights and axles.

GPM alloy uprights were used up front because they have cutouts to allow more steering angle, important with the many sharp turns on a typical RC rally course. I chose black again to fit with the colour scheme. Not a fan of the stock blue plastic ones. 

 

The back uses stock black plastic. They are the same parts as used on the Manta Ray, and I have been running one of those for a good while now with no breakages, so I foresee no issues with these. 

 

[TurnipJF 9192]

With wheels fitted, one can appreciate the benefits of the alloy uprights and their cutouts.

Not quite drifter levels of steering, but certainly better than stock.

[TurnipJF 9192]

With shocks and electronics fitted, the chassis is done.

The electronics are all waterproof - a HPI servo and ESC and a Spektrum RX. The aerial is too short to reach the stock mount location, so an aerial mount from a WR-02CB sprue has been attached to one of the unused MSC servo mounting points, and this sports a tiny aerial tube and neat rubber cap.

 

As befitting a rally car, the chassis has plenty of ground clearance even with the low profile road tyres fitted. It will be even higher when the Rally Blocks arrive.

 

I finished off the day's RC activities by doing a rough cut of the shell. Sanding, masking, painting and stickering to follow!

 

[TurnipJF 9192]

The shell is masked and ready for paint, but here we have to pause again for another delay, this time of my making. 

I could have sworn that I had some PS metallic blue paint in my stash, but when I went to get it, all I could find was PS blue and TS metallic blue. So now to wait for the paint to be delivered. I hope the masking doesn't go off in the interim - I typically don't like leaving it on for more than a few hours as the glue goes funny sometimes. 

[svenb 3778]

Should be fine with the masking, I've left mine on for a couple of weeks before. 

Is if going to be full prodrive rally livery?