My Business

I managed to flood my PC during the last race in the rain :-(

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The rc track has been relatively consistent lately which allowed me to run a suspension setup test. I started out with testing the extremes, such as super soft suspension in the front and hard in the rear and vice versa. Funny enough it turns out that the Tamiya suggested setup (the stock setup) produces the best car handling and smoothest ride on my particular track. A hard rear suspension and medium to soft front makes the car prone to oversteer, but can produce very fast laps. The lap times are (more…)

It is absolutely amazing how the Tamiya DF03-RA Subaru’s RC cars handling and driving characteristics change when switching from All Wheel Drive to Front Wheel Drive or Rear Wheel Drive.

I did a Front Wheel drive test a while back, impressions and lap timing results are available here. Now I finally had the time and most importantly consistent track conditions to run the Tamiya Subaru in AWD and RWD on the same day back to back.

In order to change the rc car to rear wheel drive only I simply removed the front drive shafts as shown in the picture below.

Granted that this does not produce the optimum performance compared to removing the main drive shaft and therefore eliminating the (more…)

I finally had the chance to explore two (popular) slotcar questions:

Who drives better – man or machine?

At what Voltage does the computer beats the human driver and vice versa?

How much does the slot car speed increase starting at 7 Volt  in 0.5 Volt increments?

All data was taken using a Slotcar track based on our outdoor RC Rally track.

Results:
Computer can’t drive slot car over 11 Volt – Car becomes to fast in corners
Ideal Voltage for Human Driver appears to be 17 Volt – At 17V the slot car has the best acceleration, breaking and top speed balance.

Building a Slotcar version of my RC Rally track was the next logical bound to happen thing to do after building a drive able computer game version of the rc track.

A designed the track based on my measurements using the Carrera Slotcar Track Planner. Unfortunately we only have the “cheap” Carrera Go track – which actually has lot of potential when you replace the stock power supply with an adjustable lab power supply, replace the throttle controller with some old-school Carrera Servo 140 controllers and hook the whole thing up to your computer for some accurate lap timing.

Here is my modified Carrera Slotcar Power-Control-Timing Setup:

Here is the Carrera Slotcar Track-Planner Render:

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Here is a my RC backyard track re-created in Torcs to be enjoyed on a PC or Linux machine near you :-)

Simply download Torcs, install it, unpack the backyard3.zip file and move the folder into your torcs dirt track folder.

Watch the Video of my Torcs RC Car Track here or read the blog post here.

Here are some Torcs RC car track screenshots:

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It seemed like a fun idea to build a drive-able computer car racing game based on our R/C backyard track and our Subaru Tamiya Rally car. Needless to say that it does not come even close to any of today’s Xbox360 or PS3 games, but that wasn’t the point in the first place. Driving my own track on the computer while looking at the “real thing” out of the window still makes me happy :-)
With the initial experience and all the measurements taken I am really tempted to build the whole thing on XNA Express to make it playable on the 360. I am afraid they will have released 3 new models of the 360 until I figure it all out though…

I have been running a Brushless Novak Motor ever since I build my backyard RC track. However during the last rain session I fried the Speed Controller (water and wet mud got in it) which forced me to switch to Tamiya’s stock 540 motor. The lack of response, torque and top end speed was immediately apparent, but and that should be a bold yelling “BUT”  – the Tamiya Motor has a higher resistance when turning over, which essentially acts as brakes when easing of the throttle in or before corners.

After several laps of getting used to the new handling I was actually able to turn faster lap times compared to the Brushless motor thanks to the new found “breaks” that allow me to get of the throttle later.

I have to investigate if there are Electronic Speed Controllers for Brushless motors that would allow me to adjust the coasting (breaking) resistance when letting off the throttle.

Did anyone notice how back in the day a lot of racing video games used to come with a track editor?

I own a good amount of newer Xbox360 and Playstation3 racing games, yet none of them has a track editor. Before I receive email from PS3 fanboys -  I don’t consider “Modnation Racer” a racing game in the sense of simulation racer. It is a lot of fun though. Gran Turismo 5 may of course change all this but we’ll have to wait until it is released to find out how useful the track editor is to create a virtual replica of  a backyard RC track.

For the time being I downloaded one of the longest running, most established and best of all “FREE” PC racing simulators available. The racing simulator is called ” Torcs” which stands for “The Open Racing Car Simulator”. As the name implies the game is Open Source and available for (more…)

Just out of curiosity I removed the rear drive shafts going to the wheel on my Tamiya df03ra and ran it on the rally track that I set up in the backyard.

The car is much to light in the front (which was clearly visible right from the start) for making it a serious front wheel drive contender. I did not have the chance to run the front wheel drive configuration on tarmac, things might look different there.

One of the positive aspects of having the (more…)

Everyone with a Tamiya model in North America has the chance to win little prices once a month by submitting their car, truck or military model to the builder showcase.

The drawing for first price is random, so don’t be disappointed if your model is the best looking but didn’t win.

Click on the photolink of my Subuaru WRC in the mud to check out the Tamiya Builders Showcase.

Infomation on how to submit your model can be found on the Tamiya website.

Now that the track is build and the racing line is measured I of course want to know how fast my car is. Unfortunately my current webcam based lap counter software does not have a function where it calculates the average speed based on track length.

I posted earlier how to calculate gear ratios and top speed. I also compared  the RPM’s and MPH of Tamiya’s stock motor with a Brushless motor.

Here is the math to figure out the average speed:

Average Miles Per Hour

Average Speed = Total Distance divided by Total Time

D = distance (length of the track) in feet = 130 feet
T = time in seconds  = 14.716 seconds (based on 4 test days and 3 race days)
S = speed in miles per hour

To convert seconds to hours use 3600 (because there are 60 seconds in a minute and 60 minutes in an hour)
To convert feet to miles use 5280 (because there are 5280 feet in one mile)

S = 130 feet / 14.716 seconds = 8.83 feet per seconds

8.83 feet per seconds x 3600 = 31788 feet per hour

31788 feet per hour / 5280 = 6.02 miles per hour

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Average Kilometers Per Hour

Average Speed = Total Distance divided by Total Time

D = distance (length of the track) in feet = 39.62 meter
T = time in seconds  = 14.716 seconds (based on 4 test days and 3 race days)
S = speed in kilometer per hour

To convert seconds to hours use 3600 (because there are 60 seconds in a minute and 60 minutes in an hour)
To convert meter to kilometer use 1000 (because there are 1000 meter in one kilometer)

S = 39.62 meter / 14.716 seconds = 2.69 meter per second

2.69 meter per second x 3600 = 9692.3 meter per hour

9692.3 meter per hour / 1000 = 9.69 kilometer per hour

At first I thought I had it all figured out by using a laserpointer to trigger my lap timer and  lap counter software.

BUT… turns out that my Rally car is “loosing paint” and the laser shines right through the body and triggers the software to count the car 2-3 times each time it comes by.

I also wanted to keep setup time to a very minimum and decided to built a mechanical contact that would simply trigger when the (more…)

Finally a little bit of rain and some mud on the track. Rally racing is just so much more fun in the rain.

Take a look at the RC Rally pictures of the day.

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I have been running my Subaru now for 1 month on my Rally track in the backyard. Well to be precise I have been running it on the weekends so all in all 5-6 times.

Turns out that I completely under-estimated the amount of “damage” that the car does to the track.  I really thought I packed the dirt down enough… The weather sure does not help either. We have one of the driest winters in years. A little rain would probably help compacting the track. Plus I am itching to run the car in the rain and mud. Sort of like the old days of the Rally Great Britain.

The RC car is loosing paint, especially in the hood area (more…)

Racing events held at night under floodlights have captivated me since early childhood. The atmosphere is simply magical. A logical thing to do was of course to install lights for our remote control rally car track in the backyard.

The idea was to build a system that would be 1) cheap 2) easy to setup and take down 3) able to withstand some very light drizzle /rain.

Luckily we had 3 construction lights and (more…)

Finally the wait is over!

Today was the first day the car went on the backyard track.

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Good News:

• Car handles like a champ
• Surprising off-road capabilities even in soft gravel
• Plenty torque and still enough speed using a 7:1 ratio and Brushless Novak motor

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Bad News:

• Track is too narrow in some areas
• My lower chicane is too tight for the steering radius of the Subaru
• Track is a bit short
• Speed Controller and Receiver dust cover still let’s to much dirt in

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The “packing” of the track is making good progress. Putting plywood and old carpet for about a week onto the track creates a nice compaction of the soil. Think of it as snow being packed down by a snow cat.  We had several rain showers which aided the process. Due to the fact that I have only a limited supply (more…)