How To Get Into Hobby RC: Small-Scale Cars and Upgrades

When I first got into RC cars in the late 1980s, the vast majority of vehicles were 1/10-scale. There were a few 1/12-scale carpet racers, a handful of nitro-powered 1/8 scale cars, and some very rare gasoline-powered 1/4-scale jobs – but it was overwhelmingly a 1/10-scale hobby. It was a good fit for the motor, battery and radio technology of the era.

While tenth-scale has remained king over the years, new technology has allowed other scales (both larger and smaller) to blossom. One of the most popular new scales to emerge is 1/18. These vehicles are small enough that they are practical for indoor use, while still being large enough to handle most outdoor terrain. Best of all, many 1/18-scale vehicles are designed just like their bigger brothers, with the same array of replacement and hop-up parts.

THE DB4.18 (LEFT) AND MT4.18 ARE BOTH 1/18-SCALE RC CARS BASED ON THE SAME 4WD CHASSIS DESIGN.

The Dromida MT4.18 and DB4.18

To illustrate the inner workings of 1/18-scale, I’ve tested a pair of vehicles from Dromida, the MT4.18 and DB4.18. Like other 1/18-scale Dromida vehicles, these cars are based on the same 4-wheel-drive chassis, with only wheel/tire, gearing, and styling differences among them. Don’t let their small stature fool you. These are hobby-grade products with full-ball bearings, a 2.4GHz radio system, oil-filled shocks, etc. They can be found for around $100 ready-to-run.

The MT4.18 and DB4.18 (let’s just call them “MT” and “DB”) are factory-built and ready to run when you open the box. There’s just the small detail of charging the included 6-cell 1300mAh NiMH battery. That quickly brings us to my only real gripe of these vehicles. The provided charger is pretty lame. It’s an AC charger that takes four hours to charge a depleted battery—four hours!

THIS OVERVIEW OF THE MT4.18 SHOWS THAT IT HAS MANY OF THE SAME COMPONENTS AND DESIGN FEATURES OF LARGER RC MODELS.

The battery can certainly withstand a much faster charge rate. I’m a big fan of multi-chemistry chargers that can do it all, but their expense can be hard to justify for beginners. An inexpensive no-frills charger such as the Duratrax Onyx 110 would be a big step up here. With the Onyx, you’re now down to 78 minutes at a 1 amp charge and 39 minutes at 2 amps (which I’d only do occasionally). Also, since it has AC/DC input, you can charge from your car battery if you’re away from home.

I used the included charger a few times just to make sure it worked (it did), and thereafter used my Hitec X4-Eighty for charging (at 1.3 amps). I don’t know the origin of the included power connectors, but I have seen them on other 1/18-scale vehicles as well. I’m sure they work fine for the moderate amperage rates seen with these cars. However, I changed mine to Deans Ultra Plugs because that is what I use for just about everything in my RC stable. I homogenize wherever I can.

The MT and DT are powered by a brushed 370-size motor. An Electronic Speed Control (ESC) for the motor is integrated into a single unit with the radio receiver. The steering servo is a separate, replaceable unit. All of these onboard components are advertised as waterproof. I never specifically tested that claim, but I have run both cars through puddles, mud and snow, with no ill effects.

The wheels are motivated via a shaft-drive system with a longitudinal motor mount and gear differentials front and rear. The gears are all plastic (other than the brass pinion gear) and contained in sealed housings. The axles, dogbones, and shaft are plastic as well.

DROMIDA’S VEHICLES INCLUDE A FULL-SIZE 2.4GHZ PISTOL GRIP TRANSMITTER THAT WORKS WELL.

From a suspension standpoint, the Dromida cars are very similar to larger RC vehicles. They have nylon A-arms with upper links on each corner and plastic oil-filled coil-over shocks. The upper camber links can be adjusted for length, but there are no alternate mounting positions. The steering rods are a fixed length, so toe-in/out is not adjustable with the stock hardware.

The differences between the two models are few. The MT has a monster truck body, while the DB resembles a dune buggy with a roll cage and painted panels. Another feature of the DB (shared with the DT4.18 Desert Truck) is a set of lights atop the body.

Although the cars are small, the included radio is not. It is a full-size 2.4GHz pistol grip unit. An interesting feature of the radio is that it offers adjustable response for steering and throttle. Dromida calls it “dual rates” but it’s really more like end-point-adjustment. The dual-rate dials are located under a flip-up panel on top of the radio – as are servo reversing switches and the power switch. Small lights let you know when the radio is on, but they’re tough to see beneath the nearly-opaque smoked lid.

Driving in 1/18-scale

My son and I have taken the MT and DB to several different locations to try them out. We’ve run them on sidewalks, smooth roads, rough roads, dirt, ice, snow…whatever we can find. The tires work surprisingly well on several different surfaces. Okay, maybe they’re not so good on ice (are any tires?). But sliding is the fun part of ice driving.

I PARTICULARLY LIKE THE DUNE BUGGY APPEARANCE OF THE DB4.18. THE TIRES WORK WELL ON VARIOUS SURFACES, EXCEPT (IRONICALLY) LOOSE SAND AND DIRT.

Unless you have a putting green lawn, these cars will get bogged down in the grass. They’ll still move, but not very swiftly. The same goes for sand and loose dirt. On paved surfaces and reasonably packed dirt, it’s go time. Dromida claims they have a 20mph top speed, and that seems about right. They’re not rocket ships, but they’re fast and powerful enough to be exciting.

The MT has larger wheels and tires – as you would expect on a monster truck. Yet, I don’t notice any distinct speed or acceleration advantage for either the MT or DB. The top speed of both vehicles on pavement is nearly equal. The run time of both cars is also equivalent, with about 10 minutes being the norm.

I like having the dual rate feature. It helps to tone down the steering on slick surfaces. By adjusting the throttle setting, I can limit the top speed to something easily controlled by little kids. That is a good ankle-saving feature to engage with newbies at the wheel.

Both of the models I tested have had their share of crashes, roll-overs, jumps, and other abuse with the damage limited to just a few scratches.

I haven’t yet found any fragile points on these cars. Both have had their share of crashes, roll-overs, jumps, and other abuse with the results limited to a few scratches. The DB has a spare tire mounted to the rear of the frame as a scale-enhancing feature. The wheel of the spare became chipped after a few harsh roll-overs, but it’s just cosmetic damage. I ended up removing the spare tire and its mount just because I prefer the way the DB looks without it.

I mentioned that 1/18-scale cars can be used indoors. I didn’t necessarily mean that you’d want to drive them at top speed through your house (but it is fun doing donuts in the kitchen). Rather, these cars do not require a large space to set up a track for racing. Some hobby shops set up indoor race courses for organized events. That sounds like a lot of fun. With every racer running a similar $100 car, the competition would be intense.

Hopping up the DB4.18

One of the things that people like most about RC cars is that they can be customized and souped-up just like full-scale cars. This even holds true for 1/18-scale vehicles. Dromida offers several different hop-up packages that improve the looks and/or performance of the vehicle. I installed a trio of them on my DB to see what difference they would make.

I UPGRADED THE DB4.18 WITH ALUMINUM SHOCKS AND SHOCK TOWERS. THEY MAY PERFORM BETTER, BUT I JUST LIKE HOW THEY LOOK.

The first kit I added was the aluminum shock kit. It replaces the stock plastic-bodied shocks with units made of blue anodized aluminum. The shocks come preassembled and filled with oil. The kit also includes blue-anodized shock towers to take the place of the stock nylon parts. Dromida claims that this kit provides more-consistent suspension performance since the aluminum bodies are more rigid than the plastic. That may be, but I’m not calibrated precisely enough to notice any difference. I just like the snazzy looks.

The parts are a direct swap, so it’s only a matter of removing the old shocks and towers before putting the new ones on. It took me about ten minutes. I always prefer to use a car stand when working on my larger RC vehicles. Since the DB would not fit on my normal stand, I also picked up a Duratrax Mini Car Stand that I can use with these more petite cars.

THE DURATAX MINI PIT STAND IS SIZED PERFECTLY FOR WORKING ON 1/18-SCALE VEHICLES.

Dromida offers an upgraded brushed motor for these cars as a drop-in replacement for the stock unit. I bypassed that option and went for the brushless upgrade kit. While I was at it, I figured that it would be smart to also include the aluminum drive train kit to help handle the additional power.

Since the stock brushed-motor ESC is integrated into the receiver, going brushless means that both components must be replaced (a receiver is included in the brushless package). The footprint of the new components also requires the steering servo to be relocated. All of the parts for the transformation are included, as are thorough instructions.

The aluminum drivetrain kit includes a blue-anodized spur gear, shaft, axles and dogbones. The stock differential gears and outdrives remain in place. I installed both kits at the same time. While the parts go in easily, the process requires significant disassembly. It took me an hour or two before it was squared away.

BY REPLACING THE STOCK BRUSHED MOTOR WITH DROMIDA’S BRUSHLESS MOTOR KIT, THE DB4.18 BECAME VERY FAST, YET IT STILL GETS GREAT RUN TIMES.

I can still use the stock 1300mAh NiMH battery with the brushless system, but I also added a 2S-1600 LiPo battery to my list of upgrades. The slightly-smaller LiPo is a loose fit in the battery tray, so I added Velcro to keep it from shifting around.

All of the new parts certainly made the DB look sportier. I soon found out that its performance made a huge leap ahead as well. The car almost has too much power now. I have no idea how fast it goes (Dromida claims 30mph), but it is much, much faster than stock. Acceleration is also improved.

With so much more power on tap, driving style is more of a factor now. You can’t always just punch the throttle and expect a straight hole shot. It takes a little finesse. At the same time, you can use the added power to drift through turns…or just fling more dirt, gravel, etc.

Despite the upswing in power, the greater efficiency of the brushless motor combined with the higher capacity of the LiPo, yields long run times. I’m still regularly seeing 10-minute outings in varied conditions.

The brushless hop-up definitely upped the fun factor of the DB. I still have not broken any parts of the car yet. With the power upgrade, my crashes and wipeouts have taken a rise in severity. It will be interesting to see what the weak (or perhaps sacrificial) link in the power train is. So far, I haven’t found it.

What Else

These Dromida cars were my first foray into 1/18-scale vehicles. Now I see the appeal that has made this scale so popular. It offers much of the performance and tunability of larger scales, but in a smaller, more-affordable package. In future articles, I plan to explore even smaller cars, as well as some of the big stuff.

Terry spent 15 years as an engineer at the Johnson Space Center. He is now a freelance writer living in Lubbock, Texas. Follow Terry on Twitter: @weirdflight

SOURCE:http://www.tested.com/tech/518823-how-get-hobby-rc-small-scale-cars-and-upgrades/

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