Basic Configuration of Racing Vehicles

Vehicles participating must have three or more wheels and be able to stand independently regardless of whether they are stopped or in motion.

Brake

To safely drive and reach the goal, brakes are actually more important than power. Even if the power is weak, the vehicle can still move, but if the brakes do not work properly, it cannot stop reliably. This can result in rear-end collisions or contact, causing injuries to the driver, inconvenience to other teams, and the possibility of not being able to receive the checkered flag.

Many places use bicycle brakes as their braking mechanism.
There are many places that use caliper brakes or cantilever brakes that grip the wheel rim with a brake wire to brake, as well as places that use disc brakes.

Frame (vehicle skeleton) and steering system

The frame is the main basic skeleton inside the vehicle. Think for yourself and design it yourself. Let's make a vehicle that complies with vehicle regulations.

As for the wheel configuration, most of them have a relatively simple structure with a steering device attached to the front 2 wheels and the rear 1 wheel.
In order to ensure a minimum turning radius of less than 10m, there needs to be enough space for the front wheels to turn left and right without touching the cowling, etc. In top teams, some have eliminated the space and made the width of the left and right sides compact in order to minimize air resistance, and have attached a steering device to the rear 1 wheel instead of the front 2 wheels. This makes the structure more complex and seems to be quite difficult technically.

Most vehicles attach exterior cowls to a pipe frame as their skeleton. Some also use a monocoque frame where the exterior cowl itself acts as the frame. The materials and structure that can be used are limited by the production budget and environment. The following are the basic materials used to construct the vehicle body.

●Steel Frame
Easy to obtain materials and easy to process, making it easy for beginners to handle.

●Aluminum Frame
Using a different cross-sectional shape and devising the composition of the members, the weight is lighter compared to an iron frame, and the overall strength of the frame is increased.
There are also places where the overall rigidity is increased by using structures and reinforcements such as trusses, making it the most commonly used type.

●Monocoque Frame
Some teams use high-strength fibers to make the entire cowl or the lower half of the cowl as the frame.
It requires a lot of cost and advanced technology to use the cowl as the frame.

●Fiber Reinforced Plastic (FRP)

Fiber reinforced plastic (FRP) is a composite material that improves strength by incorporating fibers such as glass fibers into plastic.
There are high-strength resin fibers such as glass fiber reinforced plastic (GERP) and carbon fiber reinforced plastic (CFRP).
In some cases, the shape and weight reduction of the cowl are prioritized, resulting in low rigidity. This can cause the vehicle to flex when the driver is riding, making it difficult to close the cowl or causing gaps to open, leading to disassembly during the race.
In case of emergency, the driver cannot escape from the inside, so it is not possible to use tape to cover the gaps from the outside.
In KV-2, the minimum weight is 35kg or more. Let's prioritize giving rigidity to the basic skeleton and aim to finish the race until the end.

Battery

●Power Motor

There are no regulations for power motors, so various things can be seen.
From used home appliances to electric cars specifically designed for racing, there are also products available from manufacturers.
Some highly skilled teams even go as far as rewinding commercially available products by hand in order to increase efficiency from power to motion.

Many vehicles use a chain to transfer power from the motor to the wheels.
Some vehicles have the motor housed inside the wheel to eliminate resistance and increase efficiency in propulsion.

Products such as motors for solar cars and Ene-1 are also sold by "Mitsuba", who is sponsoring us.

To Mitsuba's EV-related homepage

Batteries other than the designated AA rechargeable batteries specified by the event office, such as capacitors, cannot be used.
The current and voltage output varies depending on the connection method and division method, depending on the team's ideas and motor characteristics.
Three patterns are common for connecting 40 AA batteries in series and parallel, with 1.5V per battery: 4 rows of 10 in series, 2 rows of 20 in series, and 1 row of 40 in series.
In addition to the connection method, the storage method of the 40 batteries is also a showcase of skill, as they are heavy and take up space.
It is necessary to make the surface of the batteries visible so that it can be confirmed whether the designated brand is being used.

Batteries need to be easily removable with couplers, and details such as the obligation to install circuit breakers are specified in the vehicle regulations.
In recent years, participants have received sponsorship from "Panasonic" and have been provided with designated brand dry batteries and chargers for free.

Resistance (Friction)

When you try to push a vehicle that is not working, it will eventually stop running and come to a halt.
The reason why the car stops naturally is because there is resistance.
There are various types of resistance that can cause a vehicle to stop, such as rolling resistance and air resistance. In addition, there are also factors that can hinder electricity, such as the thickness and length of cables.

●Rolling Resistance
Even if the center of the axle is shifted, it becomes resistance. The elements are various even for just one rolling resistance, such as tire inch, tire width, air pressure, processing accuracy...
It's all for nothing if you increase the play of the brakes! If the brakes don't work and you make contact or go off the course, it's all for naught.
You must finish the race and receive the checkered flag, otherwise the team's record will not even be left behind.

●Electrical Resistance
In learning about electricity, it is fundamental to understand that all materials except for superconductors have some form of resistance.
The resistance value is proportional to the electrical resistance and length, and inversely proportional to the cross-sectional area. Imperfect terminals and contacts can also result in significant resistance.

●Aerodynamic Resistance
The average speed of many vehicles is over 50km/h. While the air resistance may be minimal, if you want to aim higher, consider the shape of the vehicle's exterior to reduce air resistance. Various types of cowling can be seen in order to reduce air resistance even slightly.

Driver's Environment

When riding in a small vehicle for a long period of time, it can be a heavy burden for the driver. Therefore, up to three drivers can take turns.

Drivers often lose their concentration due to pain, causing them to make contact with other cars or go off the track, resulting in no record being left behind.
Many vehicles do not have cushions in the seating position for the driver. One way to improve this is to consider creating an environment where the driver can focus on driving.
In formula cars, for example, they use foam urethane to adjust the shape of the seat to fit the driver's back and waist.
There are various environmental factors that surround the driver, such as visibility, light, temperature, wind, posture, areas where the body comes into contact, and operability.

Without being able to see ahead, you can easily go off course or collide with other vehicles. Unlike remote-controlled cars, the "Ene-1" is driven by a person.
Creating a vehicle with the driver's perspective in mind is essential for winning. Especially in long distance races, where everyone starts at the same time and speeds are high, there are many opportunities for passing and being passed.

●Put yourself in the driver's seat
It's easy to get caught up in the production of the vehicle and forget to verify the operability and visibility when the driver is actually driving.
It's also important to make sure that the driver's concentration is not affected by visual and operational stability for a comfortable driving experience.

Even with a racing machine, it is common for the driver to not be able to reach the switches once the vehicle is completed.
In the case of lying down with a full-face helmet, the chin part of the helmet may obstruct the view.
Try wearing the actual equipment to be used in the race and check the controls and visibility while riding the vehicle.

●One of the key points is for the driver to drive safely
In addition to power management and speed control, the driver should always be aware of the movements of the vehicles around them in all directions.

In case of rainy weather, vehicles with cowls can have fogged windows due to the driver's breath, causing poor visibility.
Using commercially available defoggers and water repellents to prevent fogging and prepare for rainy weather is necessary to ensure a successful journey.

In the competition, if two competing vehicles come into contact and break, the repair costs will be borne by each individual.
In each final race, 5-6 vehicles will stop and retire on the course. Even if a vehicle starts and then stops due to mechanical trouble, it cannot receive assistance from others.
If a vehicle stops on the course, the driver can repair it in a safe location. If you are worried about your vehicle, make sure to have at least basic tools on board the competition vehicle.

The desire to aim for the top is growing, but first let's think about a solid goal so that the results will be linked to the achievements we have built together so far.
A test run will also be held using the course that will actually be used before the main event. Let's go and see. Teams that are already building their vehicles can use the test run to actually run and prepare for the main event by checking for operation and any issues.

Driver's Equipment

Drivers are required to wear a one-piece suit that is completely connected from top to bottom.
Gloves must be non-military gloves and shoes that cover up to the ankles are required.
Helmets must be compliant with standards such as JIS or SNELL as stated in the regulations, and must be free of scratches.

Basic Configuration of Racing Vehicles

It is relatively easy to participate without the need to design and manufacture from scratch like KV-40, as commercially available bicycles can be used.
According to the rules, the wheel size and caster angle cannot be changed, and commercially available bicycles with a size of 20 inches or more must be used.
Since tires such as mountain bike block tires can cause resistance, I want to replace them with on-road tires.

Brake

Many places use vehicles with high stability disc brakes as their base vehicles.

Frame (vehicle skeleton) and steering system

Lightweight frames cannot be used and the saddle height must be at least 60cm.
A new step must be added to safely ride without the need for pedals.
A horn or bell must also be attached, and a cowl cannot be installed.

Power Motor

The structure must be such that when the rider's hand is released, the motor stops rotating (no electricity flows to the motor).
Compared to the KV-40, it is necessary to slow down the motor rotation and attach it to the drive chain.
Considerations such as routing from the motor to the deceleration gear chain are necessary.
Due to the rotating bodies such as the motor, gear, shaft, sprocket, and chain near the rider's feet, it is necessary to attach a cover for safety reasons.

Battery

With 40 batteries, it weighs about 1kg. The weight ratio of the bicycle is large. The motor is also one of the heavy components.
Not only does the weight balance of the vehicle affect maneuverability, but it also creates resistance during travel, so heavy objects should be securely fixed near the center of the vehicle.

In addition, at KV-Moto, since wiring is exposed, it is necessary to carefully consider the routing and fixing of the wiring so that the rider does not pull or catch the wiring when operating the handle.

Rider's Equipment

Helmets and one-piece suits are required to be worn. In addition, shoes that cover up to the ankles and elbow and knee pads are required.
Especially for riders, there are motors, chains, gears, etc. near their feet, so it is necessary to make sure that the hem of the suit does not get tangled.