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21.4.15 RRCI April 2015

Words & Pictures: Peter Gray

Half The Price...Nearly All The Features!

Sanwa MT-4s F.H.S.S 4-channel Telemetry Surface Radio System

We were sent the radio early in the third quarter of 2014, and have since used it on three of our review builds. Suffice to say it was that good that we almost ended up in an office arm wrestling match to decide who would be using it long term…but then a panicked phone call one evening from RRCi contributor Matt Tunks (right before an important round of the Soul RC Drift Championships) sealed its long term fate...

The Call Went a Little Something Like This:

“Pete, Dude, my radio just died and I’m competing at the weekend, have you anything in on review that I can use?”

After a long pause for dramatic effect I simply said: -“Oh yes!” and after jumping in the car to meet up, just 60 minutes later (It would have been 40 but Matt got lost thanks to his iPhone!) I was handing the MT-4S over to its new owner with a huge grin on my face, and the rest was history…I love it when a plan comes together! The result of that single phone call has been a solid two months of field testing by our resident Drift Guru and Yokomo Team Member Matt Tunks. He’s been competing in the Soul RC Drift Championships (as well as various other Drift events here in UK and Abroad) and alongside the radio system itself he’s also been sent one of the new ‘Sanwa SGS-01D Drift Gyro Systems’ linking it via the radios built in SSL feature and using this to have real-time control over the effect the gyro has in use. OK, so your first reaction to this may be that gyro’s are the work of the devil and shouldn’t be allowed in drifting, but this is something rather special, and very much allowed even in competition. As well as the 4WD counter steer drifting so beloved of the RRCi team, Matts also been competing in the relatively new RWD class, where drifting without a gyro is near impossible. More from the man himself later, including; his initial and long term impressions of the radio, and any tips he can offer about its setup and use.

  • But First The Techy Stuff!

    The first thing that prospective users need to know is that The Sanwa MT-4s can be operated with all existing Sanwa 2.4GHz FHSS-2, FHSS-3 and FHSS-4 car receivers. This means that if you already own a Sanwa system and have any of these receivers already installed in your vehicles, you can simply re-bind, setup the parameters you require and get on with things, something that you can’t do with ‘all’ transmitters out there today…(eh: Scott Curlin!) Next on the agenda is SSL or ‘Sanwa Synchronised Link’. This lets the transmitter interact real time with any SSL enables device and adjust parameters of its use real time. It does far more than just adjust things we are used to, like say the end points or rate of a steering servo. What we’re talking here is being able to adjusting parameters of items like the gyroscopic effect of the aforementioned Sanwa drift system, in use, even mid corner if you so desire, with an instant change! But that’s not all. By using a compatible ESC you can also change many ESC’s programming values directly from the transmitter using the transmitter's CODE AUX function. This is pretty revolutionary as is negates the need to stop, bring the vehicle in and change programming values manually through the ESC, via a laptop or field programming card. You can make these changes completely remotely and in what Sanwa call ‘higher resolution Increments’ for ‘improved performance’ (in non-jargon speak that translates as:-with more precision, speed and finesse than ever before). Imagine being on your setup lap and you feel you need a little more initial punch, or that the drag brakes need increasing ever so slightly to help you decelerate when you finally let off the throttle get that long straight and turn at the end of it, just right. Well using SSL you can adjust these parameters on the fly during testing, and concentrate on racing and track time rather than continually pitting. In addition, SSL also allows telemetry data such as speed or RPM, ESC temperature, motor temperature (if supported), and battery voltage to be read directly from a compatible unit (like the LRP Vortex ZERO ESC) and displayed on the transmitter in real time! How many other radios are out there that offer these functions for such a keen price?

    Other Things to Consider

    The MT-4s has no physical antenna to break off, the antenna integrated into the carry handle that sits on top of the units body. The body itself is well made and feels like a quality product, as do all of the switches, rotary knobs and even the thumb/scroll wheel used to negotiate the menu system. Talking of the build quality and the ergonomics, the handles rubber grip can be interchanged between the regular size or a slightly fatter version, so bigger hands won’t get cramp in prolonged use, and smaller hands won’t need to stretch themselves. Its weigh (388g) and more importantly its weight distribution is also an important factor.

    After 2 months solid use Matts impression of this aspect is:- “It’s not too small for my huge hands and weighted in such a way that it’s not at all tiring to hold. That's a real bonus for me as I can spend up to 5 hours on the track in one day!”

    That would also translate over into any type of racing, where long finals and 2 days of racing are the norm, even a day’s scaling can end up tiring on the wrists if your transmitter isn’t well-balanced and ergonomic to use. Another thing to factor in, especially in RC disciplines like drifting where throttle and steering finesse is so important, is that the trigger position, its spring tension and even the steer wheels spring tension can be easily altered. The relationship between these two components is often overlooked and can actually take what is already a good transmitter up another notch, with noticeable improvements in your driving on track.

    Matt Again: “The adjustable trigger/steering spring feature helps to further tailor it to your specific personal requirements, and using it in the last 2 months of both of the UK Drift series that I compete in, the improvement steering and throttle ‘control’ and ‘feel’ was noticeable in my performances…”

    Other throttle related features the MT-4S possesses are ARC and EXPO. The MT4 has a choice of ‘Throttle Exponential’ (EXPO) or a very useful ‘Adjustable Rate Control’ (ARC). Unlike the expo where the settings are just + or - 5%, 10, 15, etc (a regular curve), the ARC feature allows you to set at what point of the throttle travel the rate will start to increase exponentially.

    Matt: “Throttle ARC is a great feature, I use it around -20 at 70% travel to increase my ‘chassis grip point feel’...”

    RRCi: “Explain that term further”

    Matt: “Ahh yes…the tyres although plastic have a small amount of grip before they slip, you tune the chassis and everything you can to make the tiny grip point as big as possible, it's a balancing act between weight transfer and your throttle finger”

    In layman’s terms that means that when drifting Matt can set his throttle to offer him as much of this predictable ‘Grip Point’ as possible, this translates into better lines and smoother, more controlled drifts and transitions between them.

    Latency/Response Time

    Matt: “It’s way faster than my previous radio, steering inputs on transitions are amazingly fast and accurate…”

    In a world obsessed with speed, how quickly your radio interacts with the receiver, servo’s (and if electric the ESC) makes a big difference in the way a vehicle feels to drive. Quoted latency /response times have become somewhat of a marketing battle between the brands of late, but in truth most of the high end radios on the market all respond in much the same manner, but Sanwa have pulled out something very special with their M12 and MT-4s. With the MT-4s and its included receiver they quote 4.2 milliseconds, and with the M12 they quote zero latency, yes you heard that right zero, zilch, nothing, nada…but, there’s something else to consider. Compare this with a Spektrum SX3R’s default of 11ms (or even on its fastest setting 5.5ms) The fact that the human brain has its own latency when responding to visual stimuli makes a lot of that marketing obsolete, as anything between 5 and zero milliseconds will feel quite similar, above that figure and getting to 10ms and above you will start to notice a difference that’s tangible, but other factors such as the resolution and speed of the servos you use, and the way the ESC interacts with the receiver also make a big difference. For bragging rights with your mates or in the pits at a race meeting or comp it’s pretty priceless. This also leads me onto another feature of the transmitters menu, adjusting servo speed. The MT-4s has the ability to slow down the transit speed of your chosen servo’s and allow you to fine tune the way they react to steering input and throttle response above any beyond the normal curves, trims, rates etc. For obvious reasons speeding them up is impossible, digital servos are rated at a specific response time and transit speed dependent upon the maximum voltage they are rated to. But slowing them down can help reduce your tendency to say over-steer on big flowing tracks, or help get the perfect initiation of a drift.

    The Rest…

    We could spend page after page talking about every single feature this radio has to offer, I mean the manual is over 85 pages long! But telling you about the key features that make it stand out against the rest of the opposition is far more beneficial. For the money it’s truly exceptional and in the hands of an already very competent driver made a marked improvement in his results and consistency. I the hands of novice or leisure RC user it offers better control and more adjustment in setup parameters than almost any other radio on the market, especially at this price point. There are standard features that you expect all radios of this quality and price point to possess and the MT-4s doesn’t disappoint, it has: (deep breath) An 18 model memory, an LCD backlight screen for better usability, Direct Model Select, Dual Rate, Expo, Trim/Sub Trim, Servo Reverse and Endpoint Adjustment, programmable Anti-Lock Braking System, Compatibility with older receivers due to changeable modulation (FH2/FH3/FH4T), Changeable throttle mode (5:5 or 3:7), Programmable Low Voltage Alarm, A built in lap or event timer. Another very cool feature is the built in Data Logger. This allows The Telemetry Log function allows you to view a log of the Telemetry Data that is sent from the receiver to the transmitter. You are able to view Telemetry Data for both Temperature outputs, the RPM output and the receiver's Voltage. This information can be used to track specific information about your model, such as cylinder head temperature if you're running a nitro-powered model or battery temperature if you're running an electric model and much more. The interval that Telemetry Data is read and stored can be adjusted so that Telemetry Data can be stored for up to 90 minutes of use. The Telemetry Log can store 120 different data entries at intervals ranging from 00.1 seconds to 45.9 seconds…clever stuff!

    Is It Time To Upgrade?

    To sum things up, this is one very well specified radio for an amazing price. There are radios on the market that offer similar features, but none that offer all that the MT-4s can for £246.99. To fully experience every aspect of its functionality, especially the SSL, data logging, and telemetry expect to invest further in the appropriate receiver, ESC or components, but a lightweight racing receiver (RX-472) is included to get you up and running. Even at £264.99 this is still and investment for any prospective buyer, but when you consider the functionality it offers, it soon becomes very worth the outlay. Sanwa continue to push the possibilities of transmitter design and functionality, and the MT-4s is a real showcase of their achievements.

    We’ll leave the last words to Matt Tunks: “So far, since I’ve had it, the Sanwa MT-4s has helped me become UK Drift champion in 4WD, and come 2nd in the 2WD class. My old radio dying literally threw us together, and I wouldn’t consider changing from this setup and will be using it throughout the 2015 competition season and beyond…”

    We rest our case…

    For more on the whole Sanwa range and to find your nearest stockist click here

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