Posts in RC Industry News
The Paths to Speed (Series I)
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One of the most frequent questions I get asked is “How can I make my car Really FAST?!!” This is usually followed by a really vague description of the ride in question and a wish list of shiny new parts to be shoehorned into the poor little car. The problem is that many guys do not realize that there are several paths that can get you to some really nice speeds for speed runners (and drag racers). Unfortunately, you really need to have a decent understanding of each of these paths before you can pick the right direction for your particular build. Again, there is no one right path, but if you don’t appreciate what makes each one unique, you can actually pick hardware that works against itself and ultimately wastes a lot of time and money and can actually make you slower.

Before I begin, it’s important to point out that just throwing the biggest or most expensive hardware into a car rarely results in a fast RC. You really have to invest a little time and think about how all the pieces work together and tune your ride for your goal. You also have to be honest with yourself about your goals and your skill level as a driver. For example, if you are just getting into speed running or drag racing, building a Mamba XL X powered, 8S, 1/8 scale (ROSSA 808 class) world record contender may not be your best first move. I’ll talk about good starter platforms in a later post, but for now let’s just say that an “inexpensive” platform that you can easily fix after a crash (because you WILL crash) might be a better addition to your Christmas List.

“In my experience, new speed builders usually fall into one of 3 basic categories: “Torque Monsters”, “KV Kings”, and “Killa-Volters”. Each category has its own strengths and weaknesses, but the fastest guys try to take lessons from each group and apply them to their builds where they best fit.”

In my experience, new speed builders usually fall into one of 3 basic categories: “Torque Monsters”, “KV Kings”, and “Killa-Volters”. Each category has its own strengths and weaknesses, but the fastest guys try to take lessons from each group and apply them to their builds where they best fit. Just keep in mind, NEVER EVER COPY SOMEONE ELSE’S SETUP. Even though two cars may look the same, there may be some big differences under the hood, especially in ESC tuning. Copying another builder’s setup without understanding the decisions they’ve made is a great way to destroy expensive hardware (and it makes you look like a jerk). Just sayin’.

We all know that guy who insists on stuffing the absolute biggest motor and ESC possible into their cars, whether it makes sense or not. This is the guy who puts a Castle 15-series motor and Mamba XL X ESC powered by 8S LiPos in a 1/10 scale touring car…. just because he could. Sometimes this makes perfect sense….., but sometimes it does not. You see, very large brushless motors typically have pretty low KV ratings, meaning they are designed to produce their peak power at fairly low RPMs. Since Mechanical Power = Torque * RPMs, this means that the motors can produce VERY high levels of torque at pretty low RPMs, which is AWESOME for drag racers, big monster trucks, rock crawlers, or wheelie popping bashers. The problem for speed runners is that you really need to generate really, really high RPMs at the wheels to achieve high speeds. For many cars, this means running impossibly low gear ratios or extremely high battery voltages to get real speed. What usually ends up happening is the motor pulls so much current trying to just get the car rolling that the system voltage sags to a really low level. The motor then maxes out at an RPM much lower than the builder intended… and you get a “slow” run. Better batteries and beefier ESCs can greatly improve the top speeds in these cars, but this can put a LOT of strain on the system causing lots of random things to break. (More on this later).

Torque Monsters

Torque Monsters can optimize their cars by reviewing their Castle Link data logs and watching how the voltage falls during the car’s power pull and how that turns into motor RPMs (and system temps). If the voltage falls off extremely quickly (maybe even below the LiPo cutoff level), but you see slow acceleration, your car is probably waaaaay over-geared. Try backing off some in your gearing and see if this lets your motor spool up faster. On the flip-side, if your motor spins up to max RPM extremely quickly and you see little or no voltage sag during your power pull, you are probably waaaaay under-geared. Try slowly stepping up your gearing until you find a balance of current draw, motor & ESC temps, and acceleration that you can live with. And if you see wheel spin, try adding weight (if your rules allow it) to help the car “hook up” better. Even though adding weight to make a car faster sounds a little crazy, it’s all about having enough weight on the wheels to maintain traction, at least until you get fast enough to start generating downforce… but that’s a topic for another day.

Lastly, large, low-KV motors are usually set up to pull extremely high current loads, so you need to check your motor and ESC temperatures after each run with a temp probe AND be sure to check your data logs to make sure your system remains healthy. Pay particularly close attention to your logged current levels. Exceeding the recommended output of your batteries could result in a LiPo fire or explosion.  Also, ripple voltage should be in the 5-10% of system voltage range. For example, a 6S (25V) setup should ideally have ripple levels of 1.2-2.5V (or less). If your ripple voltage is in the 10-20% range, you are in the danger zone and should seriously consider upgrading to higher C-rated batteries or adding an external Cap Pack (or both). Ripple levels higher than 20% are almost guaranteed to eventually blow up your ESC.

“If your ripple voltage is in the 10-20% range, you are in the danger zone and should seriously consider upgrading to higher C-rated batteries or adding an external Cap Pack (or both).”

KV Kings

Some guys think that the answer to every speed problem is to add a higher KV motor. Sometimes this is just the ticket to unlock your car’s hidden potential ….but just because you can install a 7700kv motor doesn’t mean that you should. Let’s start by telling a little secret about motors that a lot of guys don’t realize. Most motors of a given series or “can size” from a given manufacturer are rated at about the same max output power level, regardless of KV rating. This is partially because the size of the “can” limits the amount of waste heat the motor can dump into the environment. This and the overall efficiency of the motor limit the max power you can safely extract from that motor without cooking its internal components. Period.

Again, since Mechanical Power = Torque * RPMs, this means that a Castle 1406 3800kv motor and a 1406 7700kv motor will both produce about the same amount of output power, but the 3800kv motor will have an efficient power-band that produces more torque over a lower RPM range and the 7700kv motor’s power-band will produce less torque but at a higher RPM range. Why would motor makers do this? Well, it helps them to offer motor options compatible with a wide range of RC vehicles and applications. For example, a rock crawler needs lots of wheel torque at low RPMs, but a 1/10 scale on-road racer may work better with a high RPM, low torque setup.

Without getting too technical, Brushless motors for RC cars are typically “in-runner” designs that contain several coils of wire in the stationary can body (stator) that with powerful magnets on the rotating assembly (rotor) to produce driving force. Lower KV motors use a small number of turns of thick wire that makes a lot of torque, but doesn’t want to spin very quickly. On the other hand, high KV motors use more turns of thinner wire which doesn’t make as much torque, but wants to accelerate to much higher RPMs (at a given voltage). The interesting thing is that since brushless motors must be commanded with power pulses to turn every fraction of a turn (12 pulses per turn for 3-phase 4-pole motors), a lower KV 1406 motor’s slow, powerful pulses will average out to about the same average power as the higher KV 1406 motors more rapid, but less torquey pulses, resulting in the ESC feeling the same overall load with either motor and both motors producing the same levels of waste heat. 

Blindly throwing a crazy-high KV motor into a drag or speed run car could result in the motor trying to produce high torque levels at low RPMs, which is the exact opposite of what these motors were designed for. In the Castle Link data logs, this would look just like the Torque Monster’s over-geared case. The motor would draw a lot of current, but not be able to achieve its spec’d rpm range. Unfortunately, these motors are not built to handle very large current loads, so repeated abuse like this could cause the motor to overheat and blow itself out. Also, if you exceed the suggested voltage for that motor you could exceed the max rpm rating for your motor’s rotor, causing it to physically rip apart. For example, a 1406 7700kv motor on 4S could easily spin up to over 100k rpm, voiding your warranty and causing you to have a very bad day as it shreds its innards. 

Successful KV Kings can tune their setups by figuring out a comfortable motor RPM to rev to (let’s just say 80-90% the max RPM for a given voltage) and finding the gear combination that lets the motor achieve this level while keeping the motor and ESC below 160-180 deg. F (70-80 deg. C). Also, running a Sensored motor in these applications should help minimize the current draw at startup which should also help control motor & ESC temps.

If you do all this and you are still not able to reach your speed goals, you should really consider stepping up to a larger motor class before resorting to options like overly aggressive ESC timing. Castle calls its ESC timing settings C.H.E.A.T. for a reason. Yes, it can fool a motor into running even faster (almost like adding another few teeth to your pinion), but this comes at a cost of efficiency. Less efficiency = more waste heat = more blown motors and ESCs.

“Less efficiency = more waste heat = more blown motors and ESCs.”

Killa-Volters

This last group feels that higher voltages are the key to higher speeds, and there is a lot of merit to this way of thinking (and a few pitfalls). As I’ve mentioned before Mechanical Power = Torque * RPMs, but Electrical Power = Voltage * Amperage. So, if you simply double the system voltage, you will get double the power, right? Well actually, you get even more. A LOT more. Check this out…

There’s a rule in electronics called Ohm’s Law, which says that the current that will flow through a given electrical system actually increases with your system voltage (Current = Voltage / Resistance). This means that a 6S system will actually pull twice the current as the exact same system on 3S. So, a system that pulls ~100 Amps on 3S will usually pull ~200 Amps on 6S…. and ~267Amps 8S. Since Elec Power = Current * Voltage, that means that the actual power increase from increasing cell count is a LOT more!!!

– 3S Power = 11.1V*100A = 1,110 W (~1.5 elec. hp)
– 4S Power = 14.6V*133A = 1,968 W (~2.6 elec. hp)
– 6S Power = 22.2V*200A = 4,440 W (~6 elec. hp)
– 8S Power = 33.3V*266A = 8,891W (~12 elec. hp)

So, doubling system voltage can actually give you 4X more power (assuming your system can handle the load)!!!!  These estimates are actually kind of low for Castle Products. Mamba XL-Class ESCs routinely pull 400+ Amps in real-world 8S setups.

This is probably where you say to yourself, “this Killa-Volter thing sounds AWESOME!!! What’s the catch?” Well, there are some downsides. The first is that increasing power like this put a LOT more strain on your system. I LITERALLY melted my slipper clutch on one of my first 6S speed runs. (https://youtu.be/PmuJ0ERrk90) Many guys also find that they strip all their plastic gears and start snapping driveline components. You will also put a much greater load on your batteries and ESC, so you really need to review your data logs to make sure that your voltage sag, ripple voltage, and system temps aren’t creeping into the danger-zone. As long as you follow the same tuning steps that I described earlier and you should be ok. Just start off conservatively and work your way up. Trying to make huge leaps with overly aggressive tuning is a great way to blow up your system, so try to think things through before making drastic changes.

Sooooooooo, what happens if I run my “low voltage” motor at higher-than-rated voltages? Well, it depends. If you overdo it and exceed the motor’s max RPM, it will probably blow itself up. However, Castle rates their motors to be able to perform at a high level for an extended period of time, like a several-minute race or an extended bashing session.  A drag race or a speed run is a very different creature. In this case, you may be asking your motor for an extremely large amount of power, but only for a few seconds followed by an extended cool-down period. As long as you keep your motor below the max rated rpm printed on the motor housing, watch your temps like a hawk, and employ smart tuning techniques, you may be able to push these motors to extremely high levels of performance. Just don’t expect Castle to honor the warranty if you overdo it. 😜



Disclaimer: The views and opinions expressed in this blog are those of the authors and do not necessarily reflect the official policy or position of Castle Creations Inc. The authors, blog and/or Company are not to be held responsible for misuse, reuse, recycled and cited and/or uncited copies of content within this blog by others.

CC BEC 2.0 – The Next Generation of Voltage Regulators (BEC) from Castle Creations!

From the trusted manufacturer of BECs comes the next generation of voltage regulators.  Designed and assembled in the USA1, Castle Creations’ CC BEC 2.0 gives users higher voltage ranges in two unique packages.   For pilots there is a smaller, lightweight (0.7 oz.) design capable of 14 amps peak, perfect for sport flying, helicopters, and UAVsRacers, crawlers, and other splashers can now integrate a 15 amp peak power regulator in a waterproof (WP), CNC machined, aluminum case.  Both versions handle up to an impressive 14S without brake enabled or 12S with brake.

The CC BEC 2.0 complements our established line of BECs hobbyists have relied on for years.  With hundreds of thousands in the field, users can count on this new design to power today’s high-power, digital servos and accessories safely.  The CC BEC 2.0 features heavy duty, dual output wires that will provide clean power to sensitive radio equipment. Castle Link2 can be used to set the output from 4.75 to 12 volts and power today’s power hungry servos, cameras, and other accessories.   Do it right the first time, invest in the CC BEC 2.0 to protect expensive electronics for the long haul.

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Footnotes:

  1. Assembled in the USA with foreign and domestic components.
  2. Adjustable Output Voltage may be set with Castle Link (sold separately).
  3. Ratings are determined with a 5mph airflow at 25° C (77° F). Ratings for CC BEC 2.0 are dependent on both input and output voltage as follows in chart below:
  4. Weight with full length wires, power wires may be shortened to save weight depending on application.
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NEW PRODUCT ANNOUNCEMENT- SENSORED MOTORS

Olathe KS, November 1, 2016 – Castle Creations Inc., the leader in electronic speed controllers (ESC) and BLDC motors for radio controlled (R/C) car, air, and multi-rotor hobby markets, as well as commercial UAV and drone markets, has been providing award winning brushless sensorless motors to R/C enthusiasts worldwide for more than a decade. In response to overwhelming requests, they have brought technological advancements together to deliver unprecedented performance in a new BRUSHLESS SENSORED motor line.

Efficiency and reliability were the key elements driving the development of a sensored motor design that could be pushed harder, run longer, stay cooler, and withstand harsh elements. To achieve all of these performance demands and more, Castle engineers integrated rotor position sensor technology with an improved high power and high efficiency motor design. Users will experience PRECISE THROTTLE CONTROL and BUTTERY SMOOTH starts plus the RAW POWER and LONGER RUN TIMES that Castle’s highly efficient brushless sensorless motors are known to produce. The higher the efficiency of a motor the more power it can produce without overheating; the less power it takes to produce the same output power; and the less energy it turns into heat. Efficiency equals performance, these motors are ready to be pushed harder, run longer and stay cooler.

Without a robust and reliable design, efficiency will only go so far. Oversized NMB bearings and a vibration dampening system were used to guarantee the longest bearing life possible. High-strength, high-temperature grade neodymium sintered magnets combined with a high-strength Kevlar wrap ensures the integrity of the rotor is not compromised during harsh running conditions. A proprietary winding technique is also used to produce a stator assembly that is the lowest possible resistance, resulting in a cooler running, and longer lasting, motor.

Key features of the new SENSORED MOTORS include:

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  • Designed and supported in Olathe, KS USA
  • IMPROVED 4-POLE 12-SLOT design boasts exceptional EFFICIENCY and produces LESS HEAT.
  • QUIETSENSE™ technology shields the sensors from magnetic field noise through the use of a FLUX SHIELD™ in conjunction with secondary Sense Magnets delivering even HIGHER PRECISION and MORE EFFICIENT
  • Fully optimized design eliminates the need for mechanical timing adjustments. Castle’s sensor alignment method delivers uniform timing and torque in both directions, automatically.
  • REBUILDABLE design allows users to replace front end bell/bearing assembly or rotor/shaft assembly.
  • ROAR standard sensor port and labeled connections.
  • Updated modern and sleek design; looks as cool as it performs.
  • When paired with a Castle Creations SMARTSENSE ™ sensor supported ESC, like the MAMBA MICRO X, MAMBA MAX PRO or MAMBA MONSTER X, you can unlock advanced tuning capabilities that Castle Link[1] provides specifically for sensored motors.

SMARTSENSE™ uses the motors sensors to start the motor to provide smooth starts, excellent torque, and low-speed drivability. Once the motor is turning, it seamlessly transitions to Castle’s ULTRA- EFFICIENT sensorless mode. Electronic timing in SMARTSENSE™ will advance timing automatically for peak performance during all driving conditions. This allows users to combine the best of both worlds in an unrivaled HYBRID between smooth sensored startups and high-efficiency sensorless drive.

“R/C is constantly evolving. Drivers in all applications demand clean starts when coming off the line. Crawler fans require high-precision low speed control and torque for climbing, racers need precision and predictability, and dragsters don’t have a millisecond to spare. Our goal was to design a motor that addressed all of the performance and reliability needs of the R/C surface market”, says Jonathan Feldkamp, Director of Engineering. “Users will reap the benefits of longer run times on one battery and a cooler running motor that can be pushed harder.”

Castle Creations’ initial release of eleven sensored motors, suited for 1:10 and 1:8 scale R/C Surface enthusiasts, will begin shipping in November from Olathe, Kansas.

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Media Information: http://www.castlecreations.com/media-kits

[1] Castle Link software requires a Castle Link USB Adapter and a computer that is running Windows. Castle Link is compatible with Windows Vista, Windows 7, Windows 8 and Windows 10.

NEW PRODUCT ANNOUNCEMENT – MULTI-ROTOR V5 Firmware
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speed controllers (ESC)  for unmanned aircraft systems, is excited to announce the release of a brand new, state-of-the-art and feature rich firmware, Multi-Rotor V5, for FPV racing and multi-rotor drones (UAV’s).

Castle Creations’ ESC’s are designed for use in high performance and FPV racing and multi-rotor drones and have a unique Adaptive Timing System to maximize efficiency and power output across the entire throttle range, increasing flight times and maximizing power. Multi-Rotor V5 features an extremely fast throttle response and allows for very high throttle input frequencies, resulting in increased vehicle stability.

When FPV racers upgrade to Castle Creations’ new, industry-leading Multi-Rotor V5 firmware, they will experience thrust, precision and agility like never before. Multi-Rotor V5 is a free upgrade to existing CastleLink software users and available for download through Castle Creations’ website, www.castlecreations.com.

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Additional key features include:

  • Wide input voltage range (6-25.2V)
  • High Maximum electrical RPM (300,000 eRPM) – a must have for FPV racers!
  • Adaptive Timing System for Increased Power and Efficiency
  • Low Internal Resistance for Maximum Efficiency
  • Low Latency Throttle Response – provides better stability and control!
  • Auto Detecting Servo PWM (500HZ) and OneShot 125 (4Khz) input options
  • Very Linear Throttle Response – improves “feel” in flight!
  • Active Braking – quicker throttle response when decelerating!
  • Programmable via Castle Link USB Adapter – the Castle Link software suite offers industry-leading software functions and programming capability as well as access to all firmware updates and new features at no cost!
  • Throttle Calibration and Motor Direction can be easily set in the field
  • Two versions – one with a low noise 5.6V 5A switching Battery Eliminator Circuit (BEC) and one with no BEC to reduce weight

Best Suited For:

  • FPV Racing Drones
  • Battle Drones
  • Large Camera Carrying Multi-Rotors
  • Large Payload Carrying Multi-Rotors

“We are very excited about all the performance improvements this new, innovative technology presents to the ever-changing FPV drone and multirotor markets”, says Castle Creations’ President Jonathan Feldkamp. “The new Multi-Rotor V5 firmware is optimized for multi-rotor applications – incorporating the latest technologies and advanced motor control algorithms. Consumer demand continues to increase as the market becomes more innovative. We are dedicated to providing market leading ESC products to our customers.”

Announcing the 30 Day Powered By Castle Sales Event

Throughout their history, Castle Creations has never had an “all inclusive” sale – until now! Powered-By-Castle-Sale_logoFrom October 22 through November 22, 2015, surface and air R/C enthusiast can purchase authentic Castle Creations products at significant savings off of Castle’s suggested retail prices. “As we wrap up the 2015 year, we want to make sure that our loyal customers have an opportunity to help us celebrate another year of leadership in the R/C electronics and power systems industry,” says Jeff Lacina, marketing manager at Castle Creations. “This sale is on every Castle Creations product that our distributors and resellers carry, as well as for all the regular inventory items listed on the Castle Creations website.”

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“It’s been a very busy year-and-a-half for everyone at Castle that has seen the introduction of the Talon and Mamba X Series ESCs,” notes Lacina. “We have incredibly loyal customers so we wanted to come up with a program that would reward everyone: air and surface R/C enthusiasts.”

The 30 Day Power By Castle Savings Event is being made available to all customers via Castle’s distribution and reseller organization. “If your favorite reseller or hobby shop isn’t participating in the 30 Day Power By Castle Savings Event, please ask them to contact their distributor for information about the special promotion,” explains Lacina. “Or, products can be purchased via CastleCreations.com if you don’t have a local retailer selling Castle products.”

Lacina notes that Castle-branded apparel and NeuMotors products are not included in this special, limited-time promotion.

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