WFRCCC 2007 Rules

WFRCCC entry form

WFRCCC 2007 Rules

WFRCCC RULES
1. Wheel-driven vehicles only. Vehicles powered by thrust (jet, rocket, propeller, etc.) are not allowed. Turbine power is allowed only if the turbine is used to drive the wheels, not for thrust.

2. Vehicles may be powered by engine(s) or motor(s) of any number and configuration.

3. Vehicles may be any weight, with any chassis configuration and any number of wheels—but the completed vehicle may not exceed 40 inches (1016mm) in length.

4. All vehicles must use commercially available radio gear with a functioning fail-safe system set to apply full brake in the event of signal loss or interference.

5. Vehicles are not required to look like any type of "real" car or truck, but all entries must have some type of 3-dimensional "cockpit area" with windows (clear or painted). It's OK if your car looks like a space ship as long as it appears to have a place for a guy to sit.

6. No sacrificial power systems. Motors or power systems that, by design, are inoperable after a single run are not permitted.

7. Drivers must operate their vehicles from a fixed position. Chase cars are not permitted.

8. Drivers or teams may enter as many cars as they like.

9. For a speed record to count, the vehicle must make a second run and achieve a speed that is within 2% of the record speed. The second run can be made at any point during the event, the runs do not have to be back-to-back.

ENTRANTS
Entrants will be divided into three classes: Manufacturer Team, Independent Team and Individual.

MANUFACTURER TEAM: entries fielded by RC companies will run in the Manufacturer Team class.

INDEPENDANT TEAM: if the entered vehicle is the collaboration of three or more individuals operating without the support of a manufacturer, it will run in the Independent Team class. High school shop teams, university engineering departments, RC clubs ... this is your class!

INDIVIDUAL: any vehicle entered by a single person will run in the Individual class.

THE WINNER
Each vehicle will be given three attempts to make its fastest run. The vehicle with the absolute highest peak speed will be declared the overall winner, and separate awards will be given to the fastest vehicles in the Manufacturer, Independent and Individual classes.

Some questions I've received:

What is the length of the track? It's a full-scale 1/4 mile drag strip. Use as much of the track as you like.

What’s the run up and slow down length See above. You'll have the same shut-down area as a full-size drag car.

Do we need to do 2 runs in either direction? Covered in rules posted above.

Are they one after the other or do you get a period to prepare the car for the 2nd run? Once you're up, you can make more than one run if you want, but once you take the car off the track, it will be the next driver's turn

What happens if you can’t make the 2nd run? Skip your turn, then go in the next opening. If the event runs like it did last year, we'll be following a simple "go when you're ready" system. If you're not ready to go, the next person who IS ready will go. If you're ready after him, you can take the track. It's pretty laid back, we want everyone to get all the track time they can and have a good time.

What constitutes a manufactures team? See post above.

What frequencies can we use for radio equipment? (We don’t have the same ones in Europe and don’t want to get there and have to buy new equipment) Anything you bring should be fine. All radios will be off except for the driver's on the track. I'll bring a spare radio and receiver just in case any driver has an issue.

Are we allowed to modify radio equipment? The rules state "All vehicles must use commercially available radio gear with a functioning fail-safe system set to apply full brake in the event of signal loss or interference." Personal comfort mods (aftermarket wheel or grip, that sort of thing) are ok, but electronic mods are not allowed. I changed my mind, after seeing a few of the radio-mod posts. As long as your "base" radio is an available hobby item, then it's all good.

Are we allowed to boost the output of the transmitter (2.4 ghz is no licensed up to 100 mw but you can get a license for more and boost the signal to 5 watts and get 5 miles range. Can I use this equipment in the USA?) Sorry, need to use out-of-the-box gear.

Can you use other digital frequencies? 900 mhz, 1.2 ghz, 1.4 ghz….. up to 5.8 ghz. These are not available commercially but people are looking at these systems (Me!)
I'll allow this as long as there's no performance advantage.

Speed control out for repair

Here is the "X2" currently without the speedo

Becky and I just married

I haven't been working on my car for the past 2 weeks. There are a couple reasons for that. One, I got married on July 6th and two, my HV-110 doesn't want to arm my motor. Even if my car was working, these past 2 weeks have been so busy I wouldn't have had much time to do testing anyways. The HV-110 is in the hands of Castle Creations now and hopefully I can receive a new HV-110 soon since it is still under warranty.

Video: Ground test #2

Here are some more test runs of my project "X2" speed run car. You can see that I am still having stability issues and oversteer problems. At the end of this video I almost run into John who was filming the run.
This is a test prototype of the body and wing. The body is made from fiberglass. The body attaches to the chassis with button head screws on the sides. The wing is a NACA 9509 airfoil section. I made this wing in college for wind tunnel testing.

The weather held out for John and I to do some testing. There are a couple changes I made since the first ground test. I made a longer chassis out of carbon fiber instead of G10. The G10 chassis was my prototype chassis. I used it to place my components and see if the layout was correct. I found that the car has too much over steer. I have been trying to remedy this problem with much stiffer springs in front. This did help a bit, but I found that carbon fiber has a much better resistance to a torsional load than G10. This means that the chassis bends less and the suspension can do its job more effectively.

The tests didn't prove as promising as I would have liked. I still cannot get my speed up above 30 mph. The steering is way too sensitive and it makes the car spin out. It feels like significant over steer. You can see this in the video. Right at the end my car wanders towards John and I almost hit him.

My new Futaba 3PM 2.4GHZ radio does not have nearly as much range as my very old Futaba 3PK PCM system. The 3PM gave me only about 400' of range. Very disappointing. I was hoping for much more.

After my disappointing testing on Saturday, I also didn't have a very good day today (Sunday). I was testing different front camber/caster settings to help remedy the over steer problem. I go and test a camber change, stop the car, make another camber adjustment, then I go to turn the car on and now my speed control wont arm my motor. I am not sure what the problem is at all. I tried to recalibrate the radio, I tried my old radio and I still cant get it to arm the motor. So at this point I am out of commission until I fix the speed control.

Design Update

Here is the new stretched carbon fiber chassis next to the old G10 chassis. The new one is 50mm longer in the wheelbase.

During my first couple of test runs, I had a lot of difficulty getting the car to track straight. It was tough to get on the throttle and get the car up to speed without the car getting very squirrelly. I decided to lengthen the chassis and make it out of carbon fiber instead of G10. The carbon fiber has much stiffer properties than the G10 and it seems like the chassis doesn't want to warp as it did with the G10. This lets the suspension do its job

Testing rained out this past weekend.

This is what it looked like 5 min before it started to pour
Here is John's car doing some high speed runs to check out the running surface.


This past weekend was pretty much rained out. John and I did get to go out to the testing area (Best Buy parking lot). We got a couple runs in but after 5 min it started to pour. This weekend looks promising. Much better for testing.

I got my new Futaba 3PM 2.4ghz transmitter installed. I plugged everything in but now I am having problems with the throttle again. It doesn't sense neutral. I have to hold the brake to keep the car from rolling. I am trying to set it up so it doesn't do this. I also installed much stiffer side springs on the suspension. I was using the silver 8lb/in springs before, now I am using the copper 16lb/in springs. This drastically improved the way the car handles. With the added weight of the extra battery, the car would want to keep swaying back and forth and never go in a straight line. With the stiffer springs, this has almost disappeared.

Update: I was able to adjust the throttle trims and subtrims to get my new Futaba 3PM to work with my awesome Castle Creations HV-110.