Saturday, November 17, 2007
Wednesday, November 7, 2007
The Novak GTB 4.5R Brushless Motor Review and Install
$229 Street Price
First off the question you are asking is "Why a 4.5R Brushless system on a Stampede?" The answer is because no one else
has done it, it brings just a stupid amount of power to the Stampede Project Ultra-Pede that makes it almost untouchable by a vast majority of electric and gas powered cars in almost any configuration, and it scares the living hell out of everyone at the track. The run times are a little on the short side, but what a gloriously fun 7-10 minutes it is.
One of the big reasons I choose Novak for a brushless system was because of my previous experience with their products and not so great experiences with a couple other brands. My Novak Rooster still survives today after surviving jumps, over gearing, over peaked packs, not following manufacturers recommendations and warnings, and my general driving style which in short is just abusive. Support from Novak is also supposed to be some of the industry's best and when you are dropping some serious cash on electrics, you want to know it will work.
Sensored Brushless Systems
First off the Novak system is a sensored and brushless system, meaning Novak's design specifically eliminates cogging by using a sensored motor/controller system (indicated by an extra bundle of wires going from the motor to the controller). Sensored motors are able to be more precisely controlled in theory because the sensors can talk to the controller and tell it exactly what position the rotor is in at any moment. The theory being that a sensored system can provide much smoother exact control throughout the RPM range than a sensorless system's method of motor control through suggestion. Most brushless systems (sensorless or sensored) are highly efficient and can attain much higher RPM and torque than brushed motors.
By comparison, on a sensorless system such as a Castle Creations Mamba Max, the controller makes suggestions to the motor to move forward, stop, or backward and how fast to do each very similar to your old "brushed" stock system. The thing people have noticed on older systems as glitching and stuttering at very low speeds is called cogging and was pretty annoying on older sensorless systems simply because the intention of a brushless motor was to crank continuously at near max RPM for hours on end, not rev up and down the RPM range. New sensored systems and new sensorless controllers and higher quality motors such as the Mamba Max's almost completely eliminate cogging. My experience is that I can take the Novak GTB 4.5R equipped Ultra-Pede to a obnoxiously slow dog teasing crawl with no cogging whatsoever. Need more information on brushless systems see this article by yours truly.
About the GTB Controller
What is special about the new GTB controller from Novak is that it is super crazy small with a 1"
x 1" footprint, extremely light, very high power, fully programmable, compatible with all Novak's brushless 540 sized motors (even the old ones), and will even run your old brushed motors with no turn limit restriction. The GTB is also "water resistant", noting not waterproof, and can handle a splash or two without blowing a circuit.
The GTB has four brushless modes/profiles that can be tweaked via a simple but not the easiest to use "blink and click" one button interface - you really need to be paying attention. The interface allows control of Minimum Brake, Drag Brake, Deadband, and Minimum Drive. The brushed mode is also fully programmable with all of the adjustments of the brushless
mode, plus adjustable Drive Frequency. Novak was really thinking on the design of this controller in that it's a class leading ESC for the brushed motor racing but performs all the functions as a top end brushless controller also. Although I am not that person that has a need for both, there are a percentage of people that will use this capability, should I be in a pinch, it's nice to know it's there.
Sadly the GTB's cell count is from 4 to only 6 cells, and although this produces more speed and torque than should be legal for an RC, it is a design limitation of a sensored system. Sensored systems just don't have the voltage flexibility of the sensorless systems. There will be some speed freaks out there that want to turbo charge the setup with a few extra cells, and on the GTB that would not be advised.
The GTB has included a industry standard spec brushless fan to assure the controller is kept cool. An opportunity for me to run GTB for a while without the fan occurred when my fan suddenly stopped working and I waited patiently for my warranted replacement from Novak. The GTB didn't thermal once, however I can see that running 3 or more battery packs through it in a row would really heat things up and the fan would be required. The fan really does need a little protector or cage (which I later fabricated) as any little item will remove a fan blade.
About the Motor
Novak has been selling brushless motors for a while now. The SS series motors and equipped systems were extremely popular and the SS5800 equipped system still remains a top seller and smoking deal direct from Novak's refurbished equipment department. The new Velociti motor series with accompanying GTB controller, promises more power, higher RPMs,
higher reliability, more efficiency, and more features compared to the old system.
The new motors delivers:
No Cogging--Thanks to constantly knowing the rotor position, drivers experience instantaneous throttle response & smooth transitions from neutral to drive. The rotor position knowledge is attained due to the ESC & motor being continuously synchronized via the motor harness.
Smooth & Controlled Low Speed Drivability--Always knowing the rotor angle is key to smooth acceleration without delivering abrupt and uncontrolled bursts of power (i.e. cogging).
Strong/Consistent Brakes & Starting Torque--Rotor position knowledge results in consistent starts & stops, without hesitation or inconsistent lag times before acceleration or braking--this translates to consistent lap times.
Thermal Protection--Position & temperature sensors inside motor provide unparalleled thermal protection, letting you to run pack after pack without worrying about overheating the motor, ESC, or magnets.
Cooler Operating Temps -- This new aluminum ribbed case is supposedly lighter and radiated heat better to keep the motors running cooler.
Complete Mounting Control-- This is via use of your choice of 6 motor mounting holes on the end bell, and new higher current solder tabs on the end bell which allow for a wider variety of soldering positions.
Novak 4.5R Specs:
Resistance 3.1 Mili-Ohms
Input Voltage 4-6 cells
Watts 415
KV (RPM/Volt) 9000
Some Considerations
A huge consideration is the quality, type, and capacity of the battery. Let's say you understand a garbage battery compared to something like a Trinity, GP, IB, or Sanyo and that you understand battery capacities 1500Mh, 3300Mh, 4400Mh and the like. You may also know that there is a difference between NiMH, NiCad, and the new high current LiPo (Lithium/Polymer) batteries. Before you even think the question - yes you will need the best batteries you can afford at the very least Radio Shack GP3300s.
What you probably don't know is that a good high quality battery such as a GP3300 fully charged in a Stampede running a 4.5R GTB wide open off road in the grass will last about 7-10 Minutes if you are lucky, with a IB4400 about 10-15 until full discharge. The motor is over stressing itself and is drawing tons of current in the process. The simply fact is the motor is attempting to hit supersonic speeds on speed limiting terrain with gearing that is already geared down to its limits at 12/87 on the Stampede. Those same batteries in the Stampede with a 7.5R GTB and you are looking at nearly double the run times and still about the same speeds off road. Again a 4.5R is way overboard
on a Stampede and gets really quite un-drivable as the RPMs start to spin up on flat surfaces.
The 4.5R is like putting a Ferrari motor in a 4X4, it will work and be insanely fast, but it's going to work really hard in the process. You should also consider that although a 4.5R in your Stampede would be nice and will be very fast, it's not the best choice from a battery discharge perspective. You should consider a 7.5R or 6.5R for the Stampede and leave the 4.5R and new 3.5R for the touring cars or at least the high speed on road RC's or a road tuned Rustler. Honestly with pretty much any brushless systems the biggest problem will be keeping the tires from flying off the rims and having enough batteries to make it through an hour or so.
Like every other brushless system out there this system is a current hog, big time (read below), so you will need to buy a Novak 4700mFor 5700mF capacitor and wire it to the receiver as described below to eliminate almost certain glitching from receiver power brown outs. Second, you WILL need either very high quality battery packs, ones that have soldered connections between cells, or you will need to rebuild them (as described here) to provide the current this beast requires to run properly. I reformatted all my batteries both the cheap and expensive ones to side by side packs with Deans Power Pole battery bars. After the high current conversion all worked well (although the better batteries had noticeably more punch and/or runtime) with the 4.5R brushless system.
Packaging and Installation
Novak has beautiful packaging with a nice sturdy box, and full foam cutouts that securely hold the controller and motor in place. Included in the box is the system pre-wired, a user manual, programming manual, stickers, double sided adhesive gel tape, zip ties, and warranty card. The information on the manuals is first rate, error free, contains lots of clear diagrams, and easy and simple to follow.
The system comes fully pre-wired, all that needs to be done is install in the vehicle, connect battery, program, and go. Aside from the need for a capacitor on the receiver (see below the Old Capacitor Trick) installation was simple and easy.
I would also recommend applying tape over the un-used mounting holes on the motor to further limit dirt getting into the semi-sealed motor can, and be very careful with the fragile fan that comes with the system, mine was missing one blade by the second day.
What do I think of the GTB 4.5 System?
I was disappointed and very happy with the system at the same time. There are some things that will annoy me about it and others which I was ecstatically happy about.
+ Packaging is great as well as instructions. Novak is not some slacker manufacturer that just tosses stuff in a box and leaves you to figure things out. Complete instructions, warning sheets, configuration diagrams, and ESC setting guides are supplied with plenty of links to supplemental info on their website. The ESC and Motor is nicely nestled in formed foam in an easily open-able and reusable box.
+ Installation was straight forward however I would really like to see, Novak add paragraph or two about running power and signal wires separately along the chassis as I believe this reduces radio interference and is just good practice.
- The need for a capacitor on the receiver thing really ticked me off. Novak included everything except the kitchen sink with the GTB 4.5 kit, such as nice little wire ties, double sided gel adhesive tapes and other little niceties, which were great touches and I think for the price they are expected, but left out a part that seems to be a known issue. I feel at the very least, this potential issue should have at least been noted in the instructions or a supplemental card tossed in the box as a warning.
+ My initial assessment was correct, the 4.5 system is about twice the motor as my old reliable Titanite is from a torque perspective, speed there is no comparison, the 4.5R is really fast, stupid fast. From what everyone has been saying about the brushless systems I was expecting this just wacky uncontrollable amount of power like the Hacker in Swami’s videos which seems to spend more time on it's back or wheelie-ing than driving, with so much power it is hard to drive, that in my opinion is just not the case with the Novak system. Just a smooth but huge roll of power from top to bottom. This would be an stellar racing setup. Kind of like 500HP with the traction control and vehicle stability turned on - controllable power.
+ Is it faster than just about anything you can put in a RC on 6-cells? With my limited experience and according to Novak, YES! It is nutty fast on the top end. Visually about as fast as my over gearing experiment so I am anxious to see what the speed looks like at 15/87, 17/87 and beyond and with peaked batteries. I can see where the mid forties are easy to hit with this unit for everyone. That said the new Mamba Max from Castle Creations is coming out, Novak now has a new 3.3.R motor coming, and Reedy has just introduced a brushless motor also. Hold on to you hats people the speed war has only begun.
+ & - Does it have the insane amount of wheelie popping torque which I was expecting? Yes but not like I expected. It has that power wheelie-ing flip on the lid power, but it does it in a more restrained way than I was expecting. I was expecting rolling 20+ MPH wheelies which it did not do – may be I haven’t peaked my packs yet before running or that I am a little over geared at 12/87, but unlikely.
+ To explain expectation further, let’s assume you have two cars racing, a vintage Mustang with a huge powerful motor (what I was expecting), then on the other side of the track you have a modern sports car like a Nissan 300ZX (the GTB 4.5R) which though the miracles of modern technology is just a quick. Although both will hit the finish line at the same time, the Mustang’s muscle-ly power is hard to control requires a wheelie bar and a good driver, the 300ZX with vehicle stability control, power management systems and the like is predictable enough your grandmother could drive competitively at the track. The GTB 4.5R system is like the 300ZX, you could drive is slow, you could drive is fast, it delivered a smooth power band from beginning to end. Turns out I really like the smooth output of the system.
+ Do you need a wheelie bar? Yes, buy a good one like Swami’s. You will wheelie a lot with a Stampede but not on the Rustler. The Rustler just jets off in a highly expedited manner.
+ Does the motor or ESC get hot? With my current 12/87 gearing and Moab tires, it was not even slightly warm after 3 battery packs. We will see hot it warms up at 15/87.
+ Another up is that I think my days of replacing motors which have been eaten by our wonderful gritty clay Nebraska soil are history, the motor is almost completed sealed. I did seal the other un-used mounting holes with simple electrical tape cover.
+ Cogging? – Didn’t notice any at all even a insanely slow tease the dog speeds. It's how I get my dog to chase my RC's - it's good exercise for him.
- This is a love hate thing with the fan. In my case - I hate it, I hate it, I hate it. This thing should have a thermal switch that kicks on when needed. I am sure it will be needed as gearing ratios are up’ed and the ESC heats, but it seemed kind of stupid to have it running all the time when un-needed and …I already broke a blade on the fan, isn’t heavy duty by any sense of the imagination. The fan did just stop working completely about a week in. I did notice that you DO need it after a few runs with 3 or more packs in a row. Novak did replace the fan with no questions asked.
+ Stellar post sale support - see above fan issue.
+ The GTB 4.5R is a current hog, no doubt about it. I can't give them a negative for this because every brushless system hogs current. Not a big issue but in light of the required capacitor for the receiver, I think it should be noted that a person really needs some decent long running batteries to take advantage of the system. My run times are a little shorter than with my old Rooster and Titanite and average about 7-10 minutes in grass and around 15 on hard packed and smoother surfaces.
+ Changing of profiles via the "blink and click" interface was a little tricky if you are a instruction manual skimmer vs. reader or not paying complete attention. You have to read the manual to make it work. Follow the directions and all works great. I like the profile 5 with 20% brake, reverse, and zero drag brake. The zero drag brake makes the car coast with zero braking effect from the motor and really seems to extend run times.
+ Long term testing and use has been great, I cannot think of a better setup for the Stampede. I am lying of course because the 7.5R or 6.5R would be a much better fit for a normal person but just not as much fun on smooth surfaces. I also love the look on people faces at the track when I warp by them with a Stampede. I would have however liked to see a broader cell input range so that I could drop 8-12 cells on the system. Still very impressed with the power of this system and really is un-needed for it's intended purpose - racing.
+ So far I think I would do it again - the Project Stampede Ultra-Pede Lives, It's ALIVE!!!!
- Installation Problems
So I slapped that puppy in there and glitching problems galore. Initially geared 13/87 - which from the online threads seems to be a little under geared. Da..da..da..da..daaaaaaaaaaaa.. Like it's attempting to send Morris code.
I get Zero glitching and almost non-existent cogging (as advertised) when running with the wheels off the ground, however the moment the Pede hit the ground I get Glitching when attempting a full throttle take off. If I do a slow start no glitching then I can punch it full throttle without glitching. I also get some glitching at extended 20+ foot ranges.
I also seem to only get a feel of the full power and speed when the wheels are off the ground otherwise when on ground it only seems to only have let's say about twice the power of the old Titanite.
Attempting to move the antenna around to see if it was a antenna/power wire related issue, but did nothing. Tranny is packed with plenty of Lithium Grease to minimize radio interference. Dropped a new battery in and thought for a second that cured the issue but started glitching just as before. The ESC was set at factory default, with the exception of running Drive Profile 2 (100% F/R mode). But have tired other profiles with the some glitching results. Drive frequency is fixed in brush-less mode.
The Install Resolutions from conversation with Novak
Talked with Novak tech support. Their recommendation was two fold.
A. Separate the power and signal wires, currently my are all zip tied together in a 1/2" bundle. That did nothing.
B. Purchase a 4700 or 5700Mf capacitor to plug into the battery pack slot on the receiver or use a battery pack. That should provide enough juice to the receiver to get through the power hit on the battery during hard acceleration.
What they say occasionally happens is that the is such a huge initial current draw that the receiver current drops low enough (a brown out of sorts) that you momentarily loose signal, then of course everything rebounds and the process starts over again and then the voltage pogos until you let off the trigger.
Novak was correct in diagnosing my issue. Moving the cable did nothing, although I left them separated as it seemed like a good idea.
I tucked the cap around the front of the receiver. The esc is mounted in standard placement with the power wire side of the ESC on the left (antenna side of the Pede) and the receiver and wire harness bundle is on the right. This points the blinky ESC lights forward and allows the two separate groups of wires to go around each side of the rear shock tower. I also twisted each group of wires to shorten them and hopefully cancel out any potential other interference problems. That process in itself did not relieve the major glitching issue but may reduce any other issue that may have occurred - i.e., still need a capacitor. Just covering all the bases in advance.
The receiver was in fact experiencing a "brown out" during full acceleration and with the addition of a Novak 5700Mf capacitor and the glitching issue was resolved completely.
The day after update and the snap judgment April 2006 and apparent need for better batteries.
Three things are needed to prevent glitching, an RC antenna of the correct length, very good or re-built batteries, and a receiver capacitor. Without all three glitching will continue.
Adding the cap worked. No glitching at all out to about 1/2 block then everything went nuts until I replaced my antenna wire with the correct length instead of "kind of the right length", and rebuilt the battery packs. Aside from the power wires routing one side of the rear shock tower and the harness and signal wires the other and the capacitor, everything else was left in stock placement.
Once that was done:
A. All Problems were resolved. If you buy one you will need the following:
1. Novak 5700mF or 4700mF capacitor and do the below explained simply wiring and attachment to your receiver external battery slot. Last week I went to the Novak 5700mF from the humongous the cap I had previously due mounting issues of the cap. The Novak is small enough it can be easily mounted to the receiver on the right side and works just dandy.
2. You will need either good quality "soldered" stick or side-by-side- brick packs, a good pack like a Trinity, GP, IB or other pack, or rebuild you old packs to for high current use with battery bars such as Dean Probar 3. Converting all my old packs made an enormous difference and made that motor come alive and perform like it should. If you have some lower quality packs you will need to re-build them see this on rebuilding battery packs.
3. Your antenna at the exact correct length.
B. I really love this setup know, after getting over the cap and low output battery issues, this thing is a monster and would highly recommend this to anyone looking for some serious speed and power from their Stampede.
PS. I still hate the fan.
Conclusion
Novak is a great company and the support with the glitching and the fan replacement was first rate with no complaints.
The system is reliable, fast as anything I have driven, and makes the Ultra-Pede just a blast to drive. Love it.
Testing the GTB 4.5R in something Else?
Ultra-Rusty goes Brushless
So let's say you are not quite as insane as me and have something like a Rustler or Bandit that needs a little help in the propulsion department. I am here for you. I ended up hi-jacking the Novak GTB 4.5R Brushless setup from the Ultra-Pede temporarily. In my opinion this is about as good as it gets for a race legal brushless setup for the Rusty (although the rumor is that Novak will be releasing an even faster 3.5R soon, no word on whether it will be race legal). The thought was that I need to know whether it's going to do the job or not before slapping down more cash, so why not do a test drive. I kind of wanted to see how the Rustler would handle the power anyway.
Wonderfully by the way, but I am sensing that idler gear will need replacing quickly if I don't swap back to the 15T (the 4.5R later shredded the idler gear in less than 10 runs). Again I was really expecting some wheelies with the 4.5R locked into the Ultra-Rusty's motor
mount, but instead I experienced warp-like but controlled acceleration. The acceleration was fantastic, racing winning in fact, but in some way Novak's linear power curve took a little of fun out of the equation. The 4.5R is NOT a bashers motor for wheelies but a purpose built brushless system for winning races. Kind of like trying to do donuts in the snow with your real car with the "Traction control" and "Vehicle stability control on". Sometimes you want to punch it and have the car launch forward in wheel spinning wheelie-ing madness the 4.5R does not do that, just zip and gone, at stunning speed. The Novak has that refined racing pedigree thing going on that has knocked some of the fun edges off the power plant for the average basher. All that noted, I don't know that I would want anything else in my Rustler on the track. Out on the street and the backyard I would like something to scare the heck out of the nitro guys, like a Castle Creations Mamba Max setup that I could put a big ugly stack of batteries on and move into the lutricus speed category.
Overall I really liked the 4.5R system on the Rustler and is probably what I will go with when it comes to that point. Although I would also consider the Reedy system, the GTB 4.5R is just a really nice efficient system that just works without having to pile on a bunch of batteries to see power and speed. I am going to play around with gearing a bit and have a little fun then it will go back on the Ultra-Pede where it belongs.
Perhaps Novak will grant me a test 3.5R when they come out to test on the Ultra-Rusty.
The Old Capacitor Trick - and some background on why and when to use it.
The problem - Bought a GTB 4.5R - Had tons of Glitching
So I slapped that puppy in there yesterday and glitching problems galore. Geared 13/87 - which from the online threads seems to be a little under geared. Da..da..da..da..daaaaaaaaaaaa.. Like it's attempting to send Morris code.
I get Zero glitching and almost non-existent cogging (as advertised) when running with the wheels off the ground, however the moment the Pede hit the ground I get Glitching when attempting a full throttle take off. If I do a slow start no glitching then I can punch it full throttle without glitching. I also get some glitching at extended 20+ foot ranges. Any ideas?
I also seem to only get a feel of the full power and speed when the wheels are off the ground otherwise when on ground it only seems to only have let's say about twice the power of the old Titanite.
Attempting to move the antenna around to see if it was a antenna/power wire related issue, but did nothing. Tranny is packed with plenty of Lithium Grease to minimize radio interference. Dropped a new battery in and thought for a second that cured the issue but started glitching just as before. The ESC was set at factory default, with the exception of running Drive Profile 2 (100% F/R mode). But have tired other profiles with the some glitching results. Drive frequency is fixed in brush-less mode.
The Solution from conversation with Novak
Talked with Novak tech support. Their recommendation was two fold.
A. Separate the power and signal wires, currently my are all zip tied together in a 1/2" bundle. That did nothing.
B. Purchase a capacitor to plug into the battery pack slot on the receiver or use a battery pack. That should provide enough juice to the receiver to get through the power hit on the battery during hard acceleration.
What they say occasionally happens is that the is such a huge initial current draw that the receiver current drop low enough (a brown out of sorts) that you momentarily loose signal, then of course everything rebounds and the process starts over again and then the voltage pogos until you let off the trigger.
Novak was correct in diagnosing my issue. Moving the cable did nothing, although I left them separated as it seemed like a good idea.
The receiver was in fact experiencing a "brown out" during full acceleration and with the addition of a simple 1000uf (1000mf) 35V polarized capacitor from Radio Shack the glitching issue was resolved.
What I used was a 1000uf 35V Axial-Lead (polarized) Electrolytic Capacitor .
What Capacitors do for your RC car: Caps store energy, like a battery, so think of a capacitor as very short term battery backup for your receiver or ESC. They can be used on the ESC or the Receiver whichever needs it. I found one article which indicated that your should have a cap on both your ESC and receiver as a standard piece of equipment to prolong the life of each which is typically shortened from continuous voltage fluctuations. Think of it also as a power conditioner for your electronics.
How do I make one of these things: I thought a simple Google search would turn this up, but it took some digging. What I found was that sure the more expensive and preferred 4700mf caps available at Towerhobbies.com will work, but so will the $2 ones from radio shack. The key is that it needs to have arrows on the label of the cap (a polarized capacitor), be of decent quality, 10+ volts (35V is the norm) and be at least 1000uf (same as 1000mf). The bigger the number the more current it stores, but keep in mind there is a point where bigger is just bigger, on the big side the Novak caps at 4700uf (4700mf) and 5700uf are plenty huge.
The arrow on the cap. points in the direction of current flow (from + to -) so the tip of the arrow is - and
the back of the arrow is +.
Scrounge a spare receiver jack and solder the red (+) lead to the + end of the capacitor. And the Black (-) lead to the - end of the capacitor. I also picked up the variety grab bag of Radio Shack shrink wraps and shrink wrapped everything up so no sparking could occur. I also put a nice big shrink wrap over the whole cap for protection - gee looks just like the Novak on the ESC. Then plug it into the spare battery slot on receiver, the same one you would use if you were using a battery pack on your receiver. That's it. The capacitor will charge from the power supplied from the ESC as needed and will discharge when current drops suddenly.
Crude picture but you get the idea of how to solder it together. Make sure you shrink wrap everything well. Capacitors can spark. Also note that Capacitors generally don't last forever, so if you get a year or two with heavy use you are doing great.
The glitching issue was history after this very minor upgrade.
I later gave in and picked up a Novak 5700mF cap, which I should have done in the first place it was only $5 from the hobby shop. The big difference is that although it is still 5700mF it is 10V versus 35V and is about half the size and is much easier to mount on the Stampede.
GPS'ing for Speed Speed Tuning your RC with GPS
GPS'ing for Speed
Speed Tuning your RC with GPS
by Tony Arnold StampedeProject.com
as published in RC Magazine.
$80-150 Street Price
With R/C's getting faster and faster, such as the recently reviewed 60+ MPH Jato 3.3, there are more off track races going on than ever before. For bragging rights a GPS satellite receiver, has become the standard speedometer accessory of choice. These celestial driven speedometers have even spawned virtual online racing to see who is fastest. Don't believe me? Look on any RC forum where hundreds of posts appear of "my RC is faster than yours" with GPS'ed verified speeds posted as undeniable proof. Now with the addictive speed of the superpower Mamba Max 5700 brushless motor system locked into my R/C, it seemed only natural to find out how fast the system really is and a GPS receiver is the obvious tool for the job. Starting at around $80, GPS units are not cheap and the question rattling around in my head was whether GPS units are simply a one function top speed gadgets or could they be useful long-term tuning tools.
I secured a selection of the most light and diminutively sized WASS enabled GPS units I could find. These units were Lowrance's small but full featured iFinder GO and GO2 units and Garmin's tiny 1.5"X3" wrist mountable Foretrex 101. These inexpensive "don't cry when you crash" units, do not feature PC interfacing, a color display, or updateable street maps, however they still provide all the basic features you need to tune your R/C. The ideally suited "trip calculator" feature on the units provided current, maximum, and average speeds, distance, and trip time. "Trip time" is an intriguing feature in that it only counts up while you are moving, so it can in essence function as a make shift lap timer during your practice track days or as a moving run-time meter for bashing.
There has been much debate over GPS receiver accuracy versus professional radar guns. Top of the market radar guns such as the benchmark standard Stalker II still show a +/- accuracy of 1-3 MPH. In the hands of the highly trained, radar guns can be highly accurate, however as explained to me by a friend and Police Academy instructor (who would like to remain nameless), "significant reading errors can be obtained if the unit is used incorrectly by an un-trained user... along with other variables, moving the radar gun with or against the direction of the target even slightly while obtaining a reading could also result in highly inaccurate
data." Newer laser speed guns promise the best and most accurate option for reading speed, but are hardly an affordable option for us R/C'ers and still require a second person to man the gun during the testing process. To add to the accuracy argument, inexpensive hobby or sporting grade radar guns lack the law enforcement provided training that maintains accuracy, are typically less than 40% accurate even when used correctly, and are not required to be either initially or regularly calibrated - hey but they are cheap.
The big confusion of GPS accuracy was regarding older GPS units. With WAAS (Wide Area Augmentation System), the location accuracy of a GPS unit shrank to
The RC
My highly modified Traxxas Rustler stadium truck, AKA the Ultra-Rusty, was selected as the test vehicle to be flogged. The Ultra-Rusty features a long list of modifications as well as the all powerful Mamba Max 5700 brushless system. I wanted some scientific data as to which gearing was the best for bashing, the track, or maximum speed runs. Now well armed with a three similar GPS units and the durable Ultra-Rusty, I was determined to find out how useful a GPS receiver could be to an R/C'er.
Tuning
Testing proved interesting as most GPS measurements conflicted with my perception. If your goal is to spend time playing with gearing and cell count to determine absolute top speed of your R/C, there is no better device than a GPS unit for the job. For example I was positive that my 12 cell equipped Ultra-Rusty was faster during it's high speed runs geared at 26/87, but in reality it was about 9 MPH slower than it was at it's consistently fastest 60+MPH gearing of 22/87. Those same surprising realizations occurred again when attempting to identify my longest run-times for bashing. Using the "trip time" feature I discovered that the lowest 12/87 gearing did not net the longest actual moving run times and disengaging the drake brake in the Mamba Max profile did increase runtimes.
As you were tuning at the track for your next race, did you really know which setup was actually faster? This is where a GPS morphs from a toy to a useful R/C tool. The trip time feature becomes your own personal lap timer and the average and maximum speed readings provide real data as to which setting works and which didn't. Maybe you had a high maximum speed but a slow run because your suspension or tires are out of sync with the track or perhaps you are just geared a little too high and can't get good acceleration in the turns. Lap times still a little on the high side from lower max speeds on the straights? Time to tune the gearing. Winning races is about knowing which tire, suspension tuning, and gearing setup runs faster on particular tracks. At the track my favorite suspension, tire, and Mamba Max controller profile was again not my fastest setup, even though I could have sworn it was, until I looked at the data. My old setup was very good but a simple gear and controller profile change made my rig even faster and I would have never known without the GPS data.
These tough and highly recommended little units survived a multitude of 40+MPH wrecks throughout testing with little more than some road rash and through it all, netted big speed and tuning dividends. The information I gained will most likely put me in a higher position on the next race, allow me to bash longer, and allow me to burn someone in a street race. No longer is a GPS receiver just a toy, in my mind it is the tuning tool of the future for R/C'ing and may even assure my spot on the podium or at least bragging rights.
What to look for on a GPS receiver
At least a 12 parallel channel, WAAS compliant, with 3D capability, A trip calculator feature that provides current, maximum, and average speeds, distance, and trip time is indispensable. For a more practical all purpose GPS unit for navigating or even to help you find the location of the new track, a good base map with major streets loaded is a big plus. The basic functionality Garmin Foretrex was a perfect unit to keep weight to a minimum and it's handy wrist strap made securing the unit to a variety of R/C's quick and easy. Although not as light as the Foretrex, the inexpensive base map loaded iFinder GO units are full featured, lighter than most units, and small enough to still fit under most bodywork.
Garmin
Foretrex 101 Street Price $135
www.Garmin.com
Lowrance
iFinder GO & GO2 $80-$130
www.Lowrance.com
Tuesday, August 21, 2007
So little time so many rants...
So here it will go.
Wednesday, March 7, 2007
Castle Creations Mamba Max Brushless Motor System Review
UPDATE
Wow still one of the most deadly ESC available - Back in 2007 when I wrote the below review Castle broke ground with a PC programmable and most importantly upgradeable ESC. Aside from a few board upgrades the Mamba Max has remained the same and continued to dominate the industry with an "old" design that still leads the pack. Name three or four RC products that have not changed in the last couple years, but yet the Castle Mamba Max is still slugging away all because it's firmware can be upgraded with new features and revisions with just a USB plug.
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Castle Creations Mamba Max Brushless Motor System Review
My review as published in RC Car Magazine - March 2007
$229 - $250 Street Price
The Mamba snake is the fastest most deadly snake on earth with a top speed of up to 20 MPH, boasting up to 20 feet of slithering power, is highly aggressive, and its' bite has a near 100% fatality rate for humans. With a namesake like that, I was anxious to experience the performance of Castle Creation's new ready to run Mamba Max motor and ESC system and determine whether it was simply a marketing threat or a real performance promise.
Sensorless Brushless Systems
The Mamba Max system is a sensorless and brushless system, meaning very roughly that the ESC makes suggestions to the motor's rotor to move forward, stop, or backward and how
fast to do each. The earlier sensorless systems' lacked the precise rotor control of the sensored systems and was displayed as stuttering (called cogging) at very low speeds . The Mamba Max motor ESC has made the giant leap forward to eliminate cogging and features the same buttery smooth output as any of the brushless sensored systems. The big advantage of brushless systems is the almost complete elimination of motor maintenance and their much higher efficiency, RPM's and torque per volt, than brushed motors.
ROAR Approved?
The no turn limit Mamba Max ESC is ROAR approved (since none is required) and can compete currently by running any approved brushed or brushless motor. However there seems to be a ruckus about the reason Castle's CM36S Series motors are not currently ROAR approved. I would imagine there will be resolution soon.
About the Mamba Max ESC & Castle Link PC Software
Castle is very different from other controller manufacturers in that their Mamba Max controllers are fully
configurable via the CastleLink PC software and USB controller interface. The interface is truly the high point and "The Feature" of the entire system and without it the power would be unmanageable. Sure some manufacturers offer some programming control or several preset profiles, but it is anything but simple and no where near as comprehensive as Castle's offering. With Castle's PC interface there is no holding down a button for X number of blinks, clicking the same button four times, count to five, clap you hands, and do the hokey pokey... while that may be a bit of an exaggeration, it seems like that much of a pain on the other ESC's I have used and I always get it wrong and have to do it again and again.
But why the CastleLink interface? According to Shawn Palmer of Castle, "The only thing that stays the same in the brushless industry is the constant changing of motor designs and types. New designs and types have been popping up for years, and will continue to do so, and we refuse to make our customers have to purchase a new ESC every time a new popular motor comes out. So we pioneered (patents pending) a device and process to load up new software into the ESC as we add new features and new motor capability. That way, your ESC is never obsolete and the real kicker is - the software updates are all free! In effect, we are GIVING AWAY the most valuable part of a brushless ESC to our customers - the software itself."
Installation of the Castle Link software was simple and easy. Pop in the mini disk and run the install program. I did notice my Windows Defender software warned me that I was installing an "Un-approved Microsoft program", but I clicked to continue the install without further issue. Upon opening the Castle Link software, I was promptly informed that a newer version was available and asked if I would like to download it now - sure. An Explorer window popped up and opened to Castle's download site where I started looking for a Mamba Max upgrade link, I guessed at what to click on, and hit the "Download Now" link. This is were it got a little more confusing. This page says nothing about Mamba Max or that I was in the right download area of the site. But after searching Castle's site for a few minutes, I realized there was just one Castle Link software that was used to configure all their products (which is a great idea). I ended up back at the same page after this realization and clicked the "Download Now" button and then clicked "Run" from the download window. Everything updated perfectly and even my desktop icon was updated to reflect the new version of Castle Link software.
With the controller turned off, I just plugged it into my Windows based laptop, via the supplied USB cable, and the computer notified me a new USB device was found and automatically installed the device (future controller updates did not require this step). Within seconds I was quickly able to tinker with the infinitely adjustable Throttle and Brake Curves, Punch Control to dial in the horsepower just where I want it, Brake Strength to keep me tracking straight under hard braking, Drag Brake to help my corner entries, Start Power for smooth launches, Cutoff voltage to keep my LiPo's happy, and Timing Advance for that final tweak in performance. The Castle Link software was extremely intuitive (shown below) with plenty of help balloons to walk me through the process or address any questions.
It may seem this level of configurability is overkill, but in reality it is needed to keep the power and capacities of the system in check. Words cannot begin to explain the ingenuity of this interface - I only wish I had this much control on any other ESC. Need a bump in horsepower after 1/2 throttle, to reduce braking force for low traction
surfaces, and kill reverse? In a couple clicks the settings are done and uploaded and you are on your way. If you really go wild, a handy "Default" reset button appears on each tab.
For those of you who still do not own a PC (or are running a Mac), the controller can still be tuned using an old fashioned beep and click interface.
Save you Settings - Having a laptop handy to tweak settings on the CastleLink software at the track or while out bashing, is almost as addictive as driving. All your different tuning profiles can be saved and accessed easily so converting back and forth from your bashing, high speed road, track, vehicles, suspension, wheels, motor, or gearing settings are just a click, load file, and update away. This type of flexibility will change R/C 'ing forever. Better yet, the Castle link system allows you to share your favorite highly customized profiles with anyone just like this www.StampedeProject.com/CastleLink_Profiles/ - very cool. I suggest Castle make available some standard profiles or even some Factory Team Castle profiles that could be downloaded from their site. How cool would it be, to be able to run the exact same profile as one of the Castle Factory Team guys?
Did I also mention that the software provides one click updates for the controller's firmware with the latest and greatest software release from Castle Creation for free? All you need is an internet connection and simply click the "Update ESC Software" button in the CastleLink interface - great to know the unit will still be running cutting edge software a year, two, or three from now. It is about time someone in the R/C industry thought of this and made it this simple.
The Mamba Max encloses the electrics in a nice sturdy case that feels tough. Other features include automatic detection of cell count or LiPo configuration, ability to run a brushed motor with no turn limit with reversible or high power configuration option, and even includes an on/off switch. Oh yeah, all this smoking power and it's waterproof, however Castle does not market is that way due to legal restrictions.
| Mamba Max Controller Specs | |
| Cells | 6-12 NiCad/NiMH (7.2V-14.4V) or 2-3s LiPo |
| Continuous | 100 amps |
| Resistance | 0.0003 ohms |
| Brake | Proportional |
| Reversible | Yes - with lockout |
| Low Voltage Cut-off | Programmable |
| Size | ESC overall: 1.9 x 1.3 x 1.2" Motor: |
| Weight (w/wires) | ESC: 2.5 oz (70.9 g) Motor |
| Connector Type | Universal |
| Weight (Motor & Controller) | 9.5oz 270g |
| Waterproof | Yes (For legal reasons it is not advertised) |
| Brushed Motor Limit | None |
ESC Research and Motor Compatibility
So this controller can do everything under the sun but will it run a motor? Yeah, in a big way. Like the Mamba (the snake not the ESC) this is one of the most deadly ESCs on the market and assuming specs are matched up with the motor, it could run any motor from a Hacker C40 brushless to a Reedy brushed motor with ease, with up to 100 amps of continuous current on tap with up to 12 cell or 3s LiPo battery input capacity. Just tip the leads of your motor of choice with 4mm Gold banana connectors, plug in to the controllers wires, and go.
To say that Castle has done some "testing" of its' controller with almost every motor out there, would be an understatement. If you have a question regarding compatibility of a brushless motor with the Mamba Max controller, drop Castle an email and they will guide you in the right direction. The easiest motor selection of course is to simply take advantage of one of Castle's great controller motor system packages.
The Mamba Max controller comes with nicely pre-tinned heavy gauge high strand battery wires ready to accept your favorite high current connector, such as the Dean's plugs I used. The controller's motor wires and the wires on the motor already have industry standard high current 4mm gold banana connectors, installed. Obviously someone at Castle realizes that you may want to do a little motor swapping. All very nice touches.
The Motors
I was, falsely, under the assumption that Castle was just picking up some existing brushless motor and simply adding some green anodizing, which is definitely not the case.
Castle informed me that they used scientific equipment to evaluate and develop an understanding of other systems' and motors' capabilities. Well designed and quality builtmotors are "easy" for the controllers to run accurately. Motors with a less than optimal design are "difficult" for the controllers to run accurately and efficiently. While looking for a motor from currently available models, Castle realized quickly that most of the sensorless motors available were not able to take full advantage of the Mamba Max controller. Although not their original intent, Castle made the hard decision to build instead of buy its' motors and now has its custom, hand made, brushless motors, built overseas, to specs which perfectly match the capabilities of the Mamba Max controller.
The result of Castle's efforts were the CM36S Series which are touted to delivery more efficiently than other motors. According to Shawn Palmer of Castle, "We use a high strength Neodymium magnet for the rotor, oversize Japanese bearings front and rear, and an optimized design for efficient operation at 500 to 1000 watts. Most other brushless systems top out at 250-500w." The new CM36S motors are limited to a maximum 65,000 RPM, if that sounds like a very high RPM number, it is. According to Castle's testing its one of the very few motors which can actually attain that "no load" number without blowing apart.
Castle decided on a three motors, a 4600 (4600Kv), 5700 (5700Kv), and 7700 (7700Kv) which were provided for testing. Externally they all look identical with the exception of a sticker on the end bell noting the Kv, maximum NiMH/NiCd cell input, and maximum LiPo input. The different motors allow you to decide how the incoming current is used, lower Kv provides more torque and a lower RPM, the higher the Kv the less torque and a higher RPM.
With the motors in hand, it is quickly noted they are precision motors of the highest quality with milled end bells and aluminum housings. The motors have pre-attached heavy gauge wires with gold high current connectors attached. Spinning the hardened rotor with milled spur notch gives you the impression of a expensive hand made Swiss watch that you should be wearing not mounting in a R/C car.
Included in the 
system's presentation quality box is a motor, the controller, a Castle Link Mini CD, a long USB cord, and a user manual. Conspicuously absent was an assortment of decals.
The Mamba Max user guide was very well thought out and provided a great quick start guide as well as hitting all the "Do's and Don'ts" in a fast, concise manner. An interesting piece of info: the Mamba Max system is an audio transducer - i.e. all the music and beeps are not made by the controller, rather electrical pulses and micro movements of the motor. I am sure someone will eventually hack the controller to play some other melody each time the controller boots.
Testing
The test vehicle was my highly customized Traxxas Rustler (the Ultra-Rusty) which provides a good baseline for performance and can handle the high speed mishaps that a
brushless system brings. I didn't want to sacrifice a brand new set of track appropriate bowties to the gods of torque and decided instead on the more durable all purpose Dirt Hawgs as a good general tire that would work well on and off road during testing. Dirt Paws were employed to test off road wheelie-ing capabilities - yes if traction is available, even the Rustler will wheelie with any of these systems.
The Mamba Max controller was installed via industrial strength Velcro. The motor and controller wires were braided and zip tied to the shock tower.
The motor mounted easily and securely via a choice of four end bell holes. Castle even supplied machine screws to mount the motor with. Although the screws were clearly intended for a aluminum motor mount and were too short for use on my Rustler. Initial controller/receiver programming was the industry standard process of doing forward, reverse, and neutral throttle recognition and is all that is required to operate the system in its' default setting mode.
The next, optional step, was plugging in the controller to the laptop for initial configuration values. Default values as follows,Brake/Reverse Type - Disabled, Brake Amount 25%,Reverse Throttle 25%, Punch Control 100%, Drag Brake 0%, Disabled, Start Power Low,Motor Timing Normal, Cutoff Voltage None, Motor TypeBrushless, Brake and Throttlecurves perfectly linear.
I left all defaults in place with the exception of turning on Reverse, geared the 4600Kv equipped Ultra-Rusty at 15/87 and grabbed a fresh peaked 6-cell GP3300 brick pack and headed outside.
First Run
With 4600Kv motor in place and controller configuration in the default "safe" mode the thing that struck me when I made the initial and subsequent runs with the other motors was that they all ran smoother than any brushless system I have driven. The 4600 was tame enough that I would feel comfortable even handing the controls to an intermediate driver. Extremely smooth power output that started like it had the torque of a good stock brushed motor, but just kept accelerating without a lot of wheel spin - exactly what you need at the track. I was impressed with the overall power, speed, and torque but not exactly what I was expecting from a system named after the world's most fast and deadly snake. I expected no holds barred power that was un-manageable.
By the time the first pack dumped, I was dieing to jump back into the CastleLink PC interface. I grabbed the laptop and reconfigured to soften the brake curve. I also disabled the punch
control and popped the start power to medium, thinking that probably wouldn't make that big of a difference. With the click of the update button my Rustler was suddenly another beast and I was about to get fatally bitten by the Mamba Max.
Not only were the brakes now working spectacular, but in this "Get Stupid" configuration I was doing less driving and more holding on for the ride, power drifting, lots of donuts, and simply attempting to maintain control. So out of control at one point during a very cool power drift I hammered my garage door hard enough to send my wife flying outside. You want fast, uncontrollable, scary, overwhelming power, you got it even in the 4600Kv (the slow motor in the group). That also doesn't take into account the ability to even further increase start power, timing, tweak the throttle curve, or add more cells, better batteries or go to LiPo's. Even with just a good 6-cell pack, I am not really sure anyone really needs more power than what the 4600Kv delivers. On my "Get Stupid" setting, no tires I used were able to maintain any semblance of traction, controlling the power of the system was serious work, and the power was anything but useable other than to scare the heck out of oneself. Luckily the Castle Link system provides all the control you need to tune the system just the way you want and remove as much of "the stupid factor", as you like with a couple clicks. This was no ordinary snake, this was one that has the ability to morph effortlessly from a elegant performer to an obnoxious class dominating power leader with the click of my mouse.
When testing the different motors, I of course had to test the 5700 with 12 cells just to see how fast it really was. Initially, I had set punch control to 50% and left the start power at medium and the result was the equivalent of attempting to drink from a fire hose, a completely un-drivable R/C. I wimped out and moved everything back to the super soft default mode. Again the Castle Link software showed its' flexibility and made the 14.4 volt power beast somewhat drivable but still allowed that amazing top speed.
My average run times came in at around 10-15 minutes with GP3300 brick battery packs in 6 or 12 cell configuration. The 7700 was on the bottom of that run time range and the 4600 on the top.
Recommendations
4600Kv - Best Bashing Motor
I think many people will get all involved with how fast they can go with the 5700Kv or 7700Kv motors and overlook the most versatile motor in the group. The 4600Kv offers the smoothest low speed feel, more power and speed than most stadium style R/Cs are able to handle and will allow for broader gearing options than the other motors, all while providing longer run times. The 4600Kv also seemed the most tunable all the way up and down the performance spectrum because it could be detuned to a stock configuration on the low end but allowed an immediate shift to something insane on the high end, up to 12 cells. Getting your feet wet in the brushless world? The 4600Kv would be my choice and is still more than most experienced drivers are ready for.
5700Kv - Most Likely to Cause Injury and Property Damage
A Darwin award winning statement, "Hey watch this!", comes to mind when testing the 5700KV with 12 cells plugged in. The 5700 hit the magic allowable voltage and maximum RPM that rocketed the Ultra-Rusty to stunning speeds. The 5700Kv is probably the most flexible system in the group sitting happily in the middle with the flexibility to run all the way up to12 cells or 3s LiPo's. This is my favorite motor on the Rustler and pick for the speed hungry stadium truck owners.
7700Kv - 6 Cell Touring Car Winner
Like all the other high Kv juice sucking motors, this motor really should have LiPo's providing the power and can drain GP3300s in under 10 minutes at full throttle. Although this is the flagship from a Kv perspective, due to RPM and Voltage limitations the speed award still goes to the 5700Kv motor running 14.4V. For dirt track racing and bashing, its' speed is beyond the capabilities of any track I know of and the run times and gearing options are also limiting - it's just too fast. Where this motor does come up golden is in a head to head, 6-cell road race and simply out spins the other two motors by a pretty significant margin and is best suited for powering touring cars.
System Ups and Downs
UPS
More controller tunable torque, power, speed than should be legal.
Super flexible system for intermediate to advanced user.
Motor/Controller wires come plug and play ready.
Battery wires come pre-tined and Motor ESC leads pre-tipped.
Great instructions.
No Cogging
Not limited to only 6 cell input.
CastleLink PC interface - Wow!
Waterproof controller
Competitively priced
Downs
No USB interface cover.
Power on "Get Stupid" setting is unusable.
Where are the yellow snake and Mamba Max decals - must have decals.
Motors not ROAR approved - yet.
No 50% power "training" mode
Conclusion
In my opinion, Castle Creations has built the best controller interface on the planet with flexibility and ESC tuning options that blows away every other system's interface. It is easy to use, clean, simple, allows simple firmware and controller updates, and most importantly, allows infinite adjustability. They have paired this powerful
software with the Mamba Max brushless ESC which can deliver more power than your R/C can handle. The new CM36S series motors that are made specifically to match the abilities of the controller and are among the best, sensorless brushless motors available to R/C'ers. Add all this together and Castle is now one of the few brushless manufacturers to offer a complete ready to run brushless system in a box. In the end the deadly Mamba Max claimed me as a victim, I am hooked.
Highly Recommended