Monday, November 12, 2018
A R/C racers primer: Notes, and Vocabulary for the new racer.
What you need to know, to go R/C car racing
So you want to go R/C racing. "I" want you to go R/C car racing. Sadly, there's a few things in your way. So lets get those barriers down.
First things first, you need to determine if your car can be race legal. Most tracks have club racing, where they have a day or two a week, that they'll have organized races. Because people like "competitive" racing, those races are usually carved up into different classes. You should call (and I do mean call.) the track and find out what's common, and popular. They'll also help you find where you can run your car.
This primer is for on-road, but off-road racing is quite similar, with fewer common classes.
There are a few things that determine what class a car would run in. Body type, weight, allowed tires, motor, esc, and chassis. That sounds like everything... and it is. The bulk of differences betwen classes really comes down to tires, body, and motor.
On-road racing has really filtered down to three major types of car. Pan cars, Touring cars, and Minis.
But first, lets cover the stuff all cars have. Motors, ESCs, servos, and batteries..
Motors, ESC's, Servos and Batteries:
Motors are specified by the number of turns. Physically, this is the number of times a wire gets wound around the motor. More turns, means a slower motor. The slowest common motor is a 25.5 turn motor.
ESCs (Electronic Speed Controllers) come in two varieties. "Blinky" and everything else. Blinky (this referers to a blinking light) indicates an ESC that doesn't change motor timing. This is used for all controlled motor classes. If a class has an open ESC, variable timing is allowed, and that class becomes "Mod" or "Modified" racing. That term is a holdover from the old days, where there was "stock" and "mod" brushed motors.
Servos, are how you steer the front wheels. They're available in roughly two sizes, and they're rated by some torque number, and a speed number. Higher torque numbers are generally good. The speed number is generally a measurement of how long the servo takes to move 60 deg. The lower the number, the better. Short servos are usually lighter than full size servos. Really cheap servos have difficulty centering, so this is a place where spending some money is a good idea.
Batteries, for most on-road racing come with four important distinctions. Cell count, C rating, cell count, and voltage limits. The number of cells is counted in "S." On road racing is either 1s or 2s. It's very rare to see 1s in anything but 1/12 scale cars. C rating tells you (or tries to tell you) how fast you can draw power from a battery. Generally the bigger the number, the better. Finally there's two max voltages available. HV and normal batteries. Most LiPo batteries are limited to 4.2v per cell max. HV cells can be charged to 4.35 volts per cell.
Chassis Types:
Ok, lets talk chassis. We'll start with the simplest.
Pan cars, which include F1, World GT-R, Pro10, and 1/12 scale cars. Are made of a flat pan of material, and a motor that directly drives the rear axle. These classes are about 50/50 1cell racing, and 2 cell racing.
Touring cars, are cars with 4 wheel independent suspension, and generally 4wd. There are some FWD and RWD touring cars, but they are uncommon these days. They can be belt, or shaft drive, but that's a concern for later.
Mini's are a offshoot of Tamiya's Mini chassis. There are now more manufacturers. But they're shorter and narrower than the typical touring car, and allow the scale use of smaller cars. Think Miata, instead of a Corvette. Mini chassis can be 4wd, FWD or RWD. Though the most common chassis are FWD.
Race Classes:
Classes of racing are usually specified by saying "Here's the style body", "here's the expected motor", "here's the expected chassis" and "here's the expected tire." So here's a short list of the common classes.
We'll start with the catchall.
Sportsman: Sportsman is typically a "run what you brung" class. Show up, with car, and they'll put you on the track. Generally, if you register for a serious racing class, you can't run sportsman. This is where some people start. It gets you track time.
Pan Car Classes:
1/12: 1/12 racing is almost exclusively 1S batteries, and tend to run very low turn motors. The slow class for 1/12 racing is typically a 13.5 turn brushless motor. Modified classes will run down to 2.5 or 3 turn. They also run foam tires, and wedge type bodies. 1/12 racing is fast, precise, and waaaay up there in the skill tree.
World GT-R: This is a 1/10 scale pan car. Narrow chassis (200mm) on rubber tires. They run 1s batteries, and a 17.5 turn motor. They're not fast, but they're very simple cars to run. You're expected to run a sports car body in World GT-R. Corvette, Ferrari, Porsche, etc..
LMP: This class is essentially 2s World GT-R. Same rubber tires, but you run a LMP style body, a 25.5 motor, and a 2s battery.
F1: Formula 1 is a pan car, that looks a lot like a modern Forumla 1 car. they are very narrow, 180mm, run rubber tires, use a 2S battery, and a 25.5 turn motor. They look great running around the track. This class is specified by USVTA
Touring Car Classes:
Touring car: Touring car is going to be a narrow rubber tire. 2S batteries, and a 4 door sedan body. Usually with a wing on the back. The classes are further narrowed by motor and tires. You'll see terms like "mod", "stock" and "spec" and "super stock". Those typically define motor and tire combinations at a local track. You will need to call to find out what those are. Mod really means anything goes.
FWD Touring Car: There are some places running FWD touring car classes. They're the same as 4wd classes. Just with front wheel drive. They tend to be easier to drive, and a bit slower than the 4wd cars.
VTA: Vintage TransAm. This is a class defined by USVTA. They're heavy at 1450g, they run a slow motor; 25.5 turn. They run 2S, and a blinky ESC. What makes the class unique, is you're expected to run a body from the first few years of TransAm racing, a spec vintage looking tire, and a driver figure. Because it's the slowest, people are encouraged to start here. It's also one of the most competitive classes in R/C.
USGT: USGT is also administrated by USVTA. The cars are lighter (1380g) than VTA, run a slightly faster motor, and you're allowed to run a GT car body. So that ranges from exotics, like the Pagani, and the FordGT, to some pretty mundane cars, like a modern Mustang or Corvette. USGT also has a rule for FWD cars. FWD cars have no lower weight limit.
Euro Truck: It's roots come from Tamiya's national event series. They sell a low end touring car chassis, with a semi truck body on it. The class is "run the kit as provided". There's typically a spec battery. It's a fun class, and very evenly matched. It's a little faster down the straight than VTA, but slower in the corners. It's fun to watch, and drive. So if you buy a Euro Truck kit, don't start buying upgrade parts, they're not allowed.
Most tracks also have their own house classes. To find out about those, you need to contact the track.
Mini: Mini is also a Tamiya based class. The cars are narrow, and short. they typically have compact car bodies on them. They're still usually 1/10 scale. There's generally a 21.5 spec motor. Otherwise the tamiya provided 27turn brushed motor is generally legal. You'll need to check with your local track for tire, and non-tamiya chassis legality.
So now you know "what people race" or more importantly, what you could race. How do you race it?
Actually going racing:
You've got your car, you know what the local classes are, you've got a car that you want to go racing with. Now you need to get there, and be ready to race, at least three times.
The facilities provided by the track can vary from "nice workbenches, with power and chairs, a pro-shop stocked with parts, and tiled indoor bathrooms" down to "well, there's parking, and a Port-o-let". Unless you know the track, definitely call ahead to find out what the facilities will be like. Always bring an extension cord.
When you call the track, you want to ask: How much is race entry? Do we need to purchase transponders, or do you provide them? Is there power, are there pit benches? What time do I need to show up to register? Is there practice time?
Bring spare parts. While racing, steering knuckles and tie rods are common failures. Also have a few spare of each type of fastener on your car. You'd also not regret a spare pinion or two, and a spare spur gear.
Your car, almost always, must be painted. So paint your car.
When you get to the track, find the race organizer. Get your entry fee paid, and make sure they know you, the transponder situation is settled, and they know what class you'll be running in.
Next is to setup your pit. Get your space cleared, get your tools out. Get your charger setup. Get your car ready, and go find out when you can hit the track.
Now, you're ready to race. Almost.
Depending on the race, you may have to put your car through tech inspection. Ask the organizers about that, when you register for the race.
The Race Itself
RC car tracks are not all that big. And once you get more than say, 8 or 10 cars on a track, things star to get crowded. To take care of this, we have qualification races, before a main race. This also means you get to drive you car a bunch of times throughout a day of racing.
It's typical to have two, three or four rounds of qualification before the main race. Often these qualification races will have the drivers re-sorted to make sure people of similar speeds are racing together. Sometimes they won't... but hey, that's racing.
Qualifiers are often what's called an "IFMAR" start. That is, you all line up at the beginning of the start/finish straight, and when your name is called, you start racing. This intentionally spaces you out, and reduces the amount of carnage at the first corner.
Mains races are usually started from a standing grid. Though rolling starts "are a thing" too.
"How to race" is an article for another time.
So you want to go R/C racing. "I" want you to go R/C car racing. Sadly, there's a few things in your way. So lets get those barriers down.
First things first, you need to determine if your car can be race legal. Most tracks have club racing, where they have a day or two a week, that they'll have organized races. Because people like "competitive" racing, those races are usually carved up into different classes. You should call (and I do mean call.) the track and find out what's common, and popular. They'll also help you find where you can run your car.
This primer is for on-road, but off-road racing is quite similar, with fewer common classes.
There are a few things that determine what class a car would run in. Body type, weight, allowed tires, motor, esc, and chassis. That sounds like everything... and it is. The bulk of differences betwen classes really comes down to tires, body, and motor.
On-road racing has really filtered down to three major types of car. Pan cars, Touring cars, and Minis.
But first, lets cover the stuff all cars have. Motors, ESCs, servos, and batteries..
Motors, ESC's, Servos and Batteries:
Motors are specified by the number of turns. Physically, this is the number of times a wire gets wound around the motor. More turns, means a slower motor. The slowest common motor is a 25.5 turn motor.
ESCs (Electronic Speed Controllers) come in two varieties. "Blinky" and everything else. Blinky (this referers to a blinking light) indicates an ESC that doesn't change motor timing. This is used for all controlled motor classes. If a class has an open ESC, variable timing is allowed, and that class becomes "Mod" or "Modified" racing. That term is a holdover from the old days, where there was "stock" and "mod" brushed motors.
Servos, are how you steer the front wheels. They're available in roughly two sizes, and they're rated by some torque number, and a speed number. Higher torque numbers are generally good. The speed number is generally a measurement of how long the servo takes to move 60 deg. The lower the number, the better. Short servos are usually lighter than full size servos. Really cheap servos have difficulty centering, so this is a place where spending some money is a good idea.
Batteries, for most on-road racing come with four important distinctions. Cell count, C rating, cell count, and voltage limits. The number of cells is counted in "S." On road racing is either 1s or 2s. It's very rare to see 1s in anything but 1/12 scale cars. C rating tells you (or tries to tell you) how fast you can draw power from a battery. Generally the bigger the number, the better. Finally there's two max voltages available. HV and normal batteries. Most LiPo batteries are limited to 4.2v per cell max. HV cells can be charged to 4.35 volts per cell.
Chassis Types:
Ok, lets talk chassis. We'll start with the simplest.
Pan cars, which include F1, World GT-R, Pro10, and 1/12 scale cars. Are made of a flat pan of material, and a motor that directly drives the rear axle. These classes are about 50/50 1cell racing, and 2 cell racing.
Touring cars, are cars with 4 wheel independent suspension, and generally 4wd. There are some FWD and RWD touring cars, but they are uncommon these days. They can be belt, or shaft drive, but that's a concern for later.
Mini's are a offshoot of Tamiya's Mini chassis. There are now more manufacturers. But they're shorter and narrower than the typical touring car, and allow the scale use of smaller cars. Think Miata, instead of a Corvette. Mini chassis can be 4wd, FWD or RWD. Though the most common chassis are FWD.
Race Classes:
Classes of racing are usually specified by saying "Here's the style body", "here's the expected motor", "here's the expected chassis" and "here's the expected tire." So here's a short list of the common classes.
We'll start with the catchall.
Sportsman: Sportsman is typically a "run what you brung" class. Show up, with car, and they'll put you on the track. Generally, if you register for a serious racing class, you can't run sportsman. This is where some people start. It gets you track time.
Pan Car Classes:
1/12: 1/12 racing is almost exclusively 1S batteries, and tend to run very low turn motors. The slow class for 1/12 racing is typically a 13.5 turn brushless motor. Modified classes will run down to 2.5 or 3 turn. They also run foam tires, and wedge type bodies. 1/12 racing is fast, precise, and waaaay up there in the skill tree.
World GT-R: This is a 1/10 scale pan car. Narrow chassis (200mm) on rubber tires. They run 1s batteries, and a 17.5 turn motor. They're not fast, but they're very simple cars to run. You're expected to run a sports car body in World GT-R. Corvette, Ferrari, Porsche, etc..
LMP: This class is essentially 2s World GT-R. Same rubber tires, but you run a LMP style body, a 25.5 motor, and a 2s battery.
F1: Formula 1 is a pan car, that looks a lot like a modern Forumla 1 car. they are very narrow, 180mm, run rubber tires, use a 2S battery, and a 25.5 turn motor. They look great running around the track. This class is specified by USVTA
Touring Car Classes:
Touring car: Touring car is going to be a narrow rubber tire. 2S batteries, and a 4 door sedan body. Usually with a wing on the back. The classes are further narrowed by motor and tires. You'll see terms like "mod", "stock" and "spec" and "super stock". Those typically define motor and tire combinations at a local track. You will need to call to find out what those are. Mod really means anything goes.
FWD Touring Car: There are some places running FWD touring car classes. They're the same as 4wd classes. Just with front wheel drive. They tend to be easier to drive, and a bit slower than the 4wd cars.
VTA: Vintage TransAm. This is a class defined by USVTA. They're heavy at 1450g, they run a slow motor; 25.5 turn. They run 2S, and a blinky ESC. What makes the class unique, is you're expected to run a body from the first few years of TransAm racing, a spec vintage looking tire, and a driver figure. Because it's the slowest, people are encouraged to start here. It's also one of the most competitive classes in R/C.
USGT: USGT is also administrated by USVTA. The cars are lighter (1380g) than VTA, run a slightly faster motor, and you're allowed to run a GT car body. So that ranges from exotics, like the Pagani, and the FordGT, to some pretty mundane cars, like a modern Mustang or Corvette. USGT also has a rule for FWD cars. FWD cars have no lower weight limit.
Euro Truck: It's roots come from Tamiya's national event series. They sell a low end touring car chassis, with a semi truck body on it. The class is "run the kit as provided". There's typically a spec battery. It's a fun class, and very evenly matched. It's a little faster down the straight than VTA, but slower in the corners. It's fun to watch, and drive. So if you buy a Euro Truck kit, don't start buying upgrade parts, they're not allowed.
Most tracks also have their own house classes. To find out about those, you need to contact the track.
Mini: Mini is also a Tamiya based class. The cars are narrow, and short. they typically have compact car bodies on them. They're still usually 1/10 scale. There's generally a 21.5 spec motor. Otherwise the tamiya provided 27turn brushed motor is generally legal. You'll need to check with your local track for tire, and non-tamiya chassis legality.
So now you know "what people race" or more importantly, what you could race. How do you race it?
Actually going racing:
You've got your car, you know what the local classes are, you've got a car that you want to go racing with. Now you need to get there, and be ready to race, at least three times.
The facilities provided by the track can vary from "nice workbenches, with power and chairs, a pro-shop stocked with parts, and tiled indoor bathrooms" down to "well, there's parking, and a Port-o-let". Unless you know the track, definitely call ahead to find out what the facilities will be like. Always bring an extension cord.
When you call the track, you want to ask: How much is race entry? Do we need to purchase transponders, or do you provide them? Is there power, are there pit benches? What time do I need to show up to register? Is there practice time?
Bring spare parts. While racing, steering knuckles and tie rods are common failures. Also have a few spare of each type of fastener on your car. You'd also not regret a spare pinion or two, and a spare spur gear.
Your car, almost always, must be painted. So paint your car.
When you get to the track, find the race organizer. Get your entry fee paid, and make sure they know you, the transponder situation is settled, and they know what class you'll be running in.
Next is to setup your pit. Get your space cleared, get your tools out. Get your charger setup. Get your car ready, and go find out when you can hit the track.
Now, you're ready to race. Almost.
Depending on the race, you may have to put your car through tech inspection. Ask the organizers about that, when you register for the race.
The Race Itself
RC car tracks are not all that big. And once you get more than say, 8 or 10 cars on a track, things star to get crowded. To take care of this, we have qualification races, before a main race. This also means you get to drive you car a bunch of times throughout a day of racing.
It's typical to have two, three or four rounds of qualification before the main race. Often these qualification races will have the drivers re-sorted to make sure people of similar speeds are racing together. Sometimes they won't... but hey, that's racing.
Qualifiers are often what's called an "IFMAR" start. That is, you all line up at the beginning of the start/finish straight, and when your name is called, you start racing. This intentionally spaces you out, and reduces the amount of carnage at the first corner.
Mains races are usually started from a standing grid. Though rolling starts "are a thing" too.
"How to race" is an article for another time.
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