Love the Tamiya Madcap

I really do.  It's a great car.  I missed it when it was originally released in 1989 because I was just starting college and had no money for RC.  It isn't a particularly spectacular car and certainly has some weaknesses, but it's fun to drive and work on.  

My first introduction to the Tamiya Madcap chassis was actually a Saint Dragon that I bought on eBay.  The chassis was too nice to use as a runner since it was never really completely finished by the original owner, so I decided to purchase a Madcap to use as a runner.  Even though the chassis was well-used, it was in good enough condition to warrant purchasing a reproduction body and original decals.

After restoring the first Madcap, I wanted more.  I wanted to try the chassis with different motors to see how it behaved.  I wanted to try some Thorp hop-ups such as the 48P gear conversion kit including the Thorp ball differential.

At the beginning of this year I bought three well-used Madcaps to go along with my box art restoration runner and give me choices of which to run.  This is the first one of the three, and I call it Madcap #2. 

The below pictures show the dis-assembly sequence.

Major damage was limited to one of the posts that holds the top front brace.  These posts are molded into the chassis tub itself and are long and thin, making them susceptible to cracking and damage.  This one broke midway up the post.  You can see the broken post still attached to the brace.

None of the Madcaps I've bought so far have had ball bearings.  Back in 1989, ball bearings were still a luxury for most people, so plastic bearings reigned supreme.

A Reedy ES motor was mounted.  The wind is unknown.  The gray substance to the left of the motor is the foam cover that has disintegrated into dust particles.

The ball differential, another of the Madcap's weaknesses, was in good condition.  Wear was minimal.

I cleaned all of the metal parts using motor cleaner.  The plastic parts were washed in the sink with hot water, dishwashing liquid and an old toothbrush.  After the parts completely dried, the chassis was rebuilt by following the Madcap manual.  Ball bearings were used throughout, and the stock blue friction shocks were replaced with black CVA shocks (50519 and 50520).  The stock soft aluminum 23T pinion was replaced with a Robinson Racing #1123 steel 23T metric (0.6mod) pinion.  The Robinson Racing 11xx series of pinions are highly recommended for 0.6mod purposes due to their high quality machining and strength.

Rebuilding the chassis was uneventful except for the front brace posts.  Attempting to glue the broken front chassis post would never work because it is simply too thin to offer any strength.  In the past I have tried CA glue and epoxy, but the joint never withstands the strain of screwing down the front brace or ultimately gives way while driving.  A very strong repair is available, however, if you are careful.  The post can be completely removed all the way down flush with the bottom of the chassis tub. The length of the original molded-in post is 25mm.  RC4WD sells aluminum links in varying lengths, including 25mm anodized in black.  These links are internally threaded to accept a 3mm machine screw on both ends.  Once the post has been removed and the plastic webbing brace structure cleared, the 25mm aluminum link can be mounted in its place.  This provides a very strong mounting point for the front brace.  Use 3mm washers with the screws on the bottom in order to widen the screw's contact area with the chassis and provide a strong foundation for the post.  I removed both plastic molded-in posts from this chassis and replaced them with the aluminum RC4WD links.  It is very stealth.  Only the space between the plastic ribbing and the post give it away.

A package shot of the RC4WD 25mm black anodized aluminum link with 3mm internal threads (part #Z-S0880).

For the motor, rather than use the Reedy, I decided to install a well-used "Demon Power" brushed motor with reflective red label.  I had gotten it as part of a used motor lot a few years ago.  I figured I'd give it a try to see if it earned its name.  As it turned out, it was not very impressive.  Maybe the magnets are weak due to abuse it received before it came into my possession but I think it barely has more power than a stock RS540 motor and certainly doesn't spin any faster.  I'll keep it in this chassis until it dies or I get bored with it.

Here is Madcap #2 finished. For radio gear, I used an old S28 servo with G to J conversion for steering (it still works perfectly, so why not?), a Futaba MC230CR ESC and a Futaba R113ip 75MHz receiver. 

The wing has seen better days for sure.  It's been reduced to just a curved flat surface by the original owner.

I am using the original body for now because it is in OK shape and is functional even if it isn't concours-worthy.

The wheels and tires are made by Carson Model Sport in the UK.  They are great for 2WD buggies that use ball bearings in the front wheels instead of hex mounts.  The tread design gives good traction and the wear is decent.  I always balance the rear tires to reduce vibration and improve smoothness.