Kyosho wild Dodge Ram and Baja Beetle QRC trucks
1/10 – SCALE NITRO
Revisiting the original reversing nitro machine
Sometimes you don’t realize history has been made-until it repeats_ W1,91- Case in point: the Kyosho QRC Field Beetle, released in 1997. When the Be was introduced th rly five ago, everyone recognized the significance of its Quick Reverse Clutch (QRC) transmission that permitted it to back up under nitro power. That was history. But it wasn’t until Traxxas released the T-Maxx that the Field Beetle’s other drive-train features could be fully appreciated. Its front and rear gearboxes were suspended beneath the chassis and joined via shafts to a reversing center transmission that was bolted to the top of the chassis but passed through it to meet the drive shafts below-in essence, the same layout as Traxxas uses sc capably on its Maxx trucks. The differences in technica details between the Maxx trucks and Kyosho’s QRC machine are myriad, but the broad strokes are the same.
Now Kyosho has released an updated version of the QRC truck chassis that, ironically, takes a page from the Traxxas design book. A disc brake has been added to the formerly brakeless drive train, and an electric starter replaces the Kyosho GSI5R engine’s pull-starter. The GS15R itself is another upgrade, as the original Field Beetle included a smaller-displacement GS-liX powerplant. The revised QRC-equipped trucks are offered with Baja Beetle and “Wild” Dodge Ram-style shells, and with Ram-fin Kevin Hetmanski’s help, I built and tested both.
VEHICLE TYPE 4WD off-road nitro truck with reversing transmission
BEST BUYER Nitro-powered truck enthusiasts who appreciate Ram and Beetle looks with reversing capability
KIT RATINGS (poor, satisfactory, good, very good, excellent)
Parts fit/finish Very good
Durability Very good
Overall performance Good
MODELS Wild Dodge Ram and Baja Beetle
DISTRIBUTOR Great Planes
STREET PRICE $320
Wheelbase 10.4 in. (264.lmm)
Width 11.4 in. (289.6mm)
Total, as tested 72 oz. (2,041g)
Type Single-deck plate
Material 2.5mm aluminum
Type Open gearbox with reverse and shaft drive
Primary Clutch bell/spur gear
Drive shafts Steel dogbones
Differentials Bevel gear
Bearing type Metal bushings
Type Lower H-arm with one-piece camber link
Shocks Plastic-body with indexed preload, oil-filled
Type 2.2-in., one-piece plastic TIRES
Type Chevron/lug tread
Good-looking, detailed bodies.
Convenient electric starting.
Solid 25mph top speed.
Reverse or brake option.
Starting the engine requires a stick pack and charger.
Transmission shifts noisily.
No brakes when vehicle is set up for reverse.
Steering and throttle servos
Universal drive shafts-part no. W5061
Engine mount for non-Kyosho engines-FD20
Steel differential ring gear-FZW13
Steel differential pinion gear-FZW15
building & setup tips
The QRC chassis is easy to assemble, and Kyosho’s instructions are well illustrated. I do wish the parts were packaged more logically so that each step corresponded at least roughly with the contents of just one or two bags, but this is a minor annoyance. Use the following tips to get the most from your QRC truck.
Mark the manual. Addendum sheets indicate the additional steps for touch-starter assembly and brake installation that the original manual omits; mark the steps in the main manual where a look at the addenda is required so you won’t miss anything later.
The usual stuff. Thread-lock the engine mount screws and throttle-linkage setscrews, glue the tires with high-quality CA, and use 4 AA alkaline cells or a 5-cell rechargeable receiver pack for best performance.
Zip-tie the air filter. On one occasion, the Beetle lost its air filter, and the dust in the air quickly coated the carb’s rotary valve and jammed it. Unless you feel like running the truck wide open from start to finish every time (bad idea), I suggest you put a zip-tie around the base of the air filter to prevent it from bouncing off.
Step 23. Skip ahead to steps 29 and 30, and install the radio box before you install the steering system. If you wait, the steering drag bar will block one of the screw holes.
Step 32. The instructions tell you to install the lower half of the throttle cam assembly on the chassis before you install the spring and the cam itself. It’s easier to assemble the cam parts first and then to Install the completed assembly on the chassis. Before you build, lightly grease the throttle cam pivot pin as well as the top and bottom surfaces of the cam itself. I found the cam tended to hang up otherwise.
Chassis. Standard nitro stuff here, with a 2.Smm aluminum plate serving as the truck’s backbone. The sides of the chassis are radiused for strength, and a prominent cutout in the center is home to the QRC tranny. Additional openings provide clearance for the engine’s flywheel and pull-starter and the inverted steering servo. A large, sealed radio box keeps the receiver and its battery safe from fuel and dirt and should look familiar to owners of Kyosho’s MP-5 and MP-6 buggies (since that’s where Kyosho borrowed the box from).
Drive train. Kyosho’s factory-assembled QRC transmission is the star of the show and is deceptively simple. It’s basically two transmissions in one, with an independent set of gears for forward and another for reverse operation. Both gear trains spin in the same direction, as their top gears are on a common shaft that is spun by the spur gear, but the reverse gear set includes a countergear that reverses the rotation of the bottom gear. To select between forward and reverse, a servo-actuated fork slides a clutch disc against the forward or reverse gear and engages the gear via a steel pin.
Understanding how the tranny shifts is simple enough, especially when you see it in action, but Kyosho had to get creative with the throttle system to be able to provide forward and reverse throttle control without a third channel. To achieve this, the QRC trucks use a cam linkage that opens the throttle and returns it to neutral no matter in which direction the servo pushes the cam; the photos make it easy to understand.
One item the QRC chassis lacked was a brake system, but the latest trucks include a transmission– mounted disc brake with steel rotor and padded calipers. Unfortunately, when you build your truck, you’ll have to decide between having a brake and having reverse capability, because you can’t have both-at least, not simultaneously. You can convert the truck from reverse-capable to brake-only (and vice versa) with a few minutes of wrenching anytime you like.
Front and rear bevel-gear differentials give the Ram and Beetle full-time 4WD, and the diffs are spun by steel ring gears and bevel pinions that connect to the QRC gearbox via steel dogbones. Likewise, steel dogbones join the diffs to the drive hubs, which are press-fit to tapered axles. As with so many of the trucks’ other parts, the Ram and Beetle’s gear cases are shared with other Kyosho vehicles, most notably the SuperTen and Inferno TR-15.
Suspension and steering. Kyosho dipped into its existing parts inventory for the QRC trucks’ suspension pieces, and outfitted them with lower A-arms and hub carriers from the TF-series touring cars. The arms are short, but thanks to deeply offset wheels, the Ram and Beetle have a wide off-road stance. Plastic-body, oil-filled shocks take care of jolt management and use clever, rotating collars to incrementally adjust preload without clip-on spacers. Molded-plastic shock towers and fixed-plastic camber links round out the suspension details.
A pair of bellcranks with a plate-aluminum drag bar and integrated servo-saver are suspended beneath the chassis and are joined to the steering arms by threaded tie rods. Aluminum standoffs on the arms raise the tie rods to minimize bump steer, and toe-in adjustments are possible.
Engine and accessories. The original QRC Field Baja Beetle was equipped with a GS11X pull-start engine, but the new Wild Dodge Ram and Baja Beetle use much more robust GS15R engines. The carburetor is a molded-plastic rotary unit with fixed low-end needle, and to increase engine cooling, a belt-driven fan is spun by the crankshaft to direct airflow over the GS15R’s short heat-sink head. An onboard electric touch-starter is new to the QRC mix; a 7.2V stick pack is required to start the engine, which is achieved by taping a starter probe to the battery and inserting the probe into a receptacle in the chassis’ rear. As soon as the pack is plugged into the receptacle, the electric starter begins cranking the engine.
A canister muffler keeps the engine quiet, and a 75cc tank holds the fuel. Kyosho also supplies its unusual but satisfactory “corncob pipe” air filter.
Body, wheels and tires. The Ram and Beetle are equipped with one-piece, 2.2-inch wheels and chevron-tread tires that have served well on numerous other Kyosho vehicles, and clear bodies with ample decals are provided. But don’t look for any body clips; instead, springloaded, flip-down tabs secure the Ram truck and VW-inspired Baja Beetle shells. Both vehicles also include chrome detail pieces, including a grill and light bar for the Ram and headlights and taillights for the Beetle.
Based on my experience with Kyosho engines, I expected the Ram and Beetle to start easily and run reliably, which they did (especially with electric starting), but I did not expect them to be particularly fast or exciting to drive. They surprised me! While neither will challenge a 2WD nitro racing truck, their top speeds of 25mph were plenty fast enough to keep driving fun, and the short-arm suspensions were more supple than I expected. Fulltime 4WD gave the Ram and Beetle excellent climbing abilities, and although they could use more damping, the trucks jumped well. Hard landings caused the steering tie rods to pop off, as they do not have as much travel as the suspension arms do, but otherwise the trucks held together well.
I’d describe the QRC trucks’ steering as OK; granted, I could have installed stronger steering servos, but the plastic servo-saver spring was the real culprit. Luckily, the fix is easy and cheap (see “Building and setup tips”) and improves steering precision noticeably.
I had the most fun driving the Wild Dodge Ram, which Kevin had built with a brake instead of reverse. The ability to back up the Beetle was novel, but the transmission makes uncool-sounding snapping and popping noises, as the clutch disc’s drive pin bounces off the forward or reverse gears before engaging. And it’s hard to avoid accidentally jamming the truck into reverse when returning the throttle to neutral. On more than one occasion, force of habit caused me to apply “brake” and slam the Beetle into reverse at top speed. Incredibly, the QRC tranny was able to handle this, even though it stopped the truck so hard that it flipped onto its roof. Kevin’s Dodge was just a lot easier to drive, and I felt having a brake was worth the trouble of a walk to kick the truck off an obstacle instead of being able to noisily back it out of trouble.
Kyosho’s engine upgrade and touch-starter make the QRC trucks livelier and more convenient to run than they were in their original release, and the option of swapping reverse capability for a brake is a welcome addition to the formula. Monster truck purists will wish for longer suspension arms and more suspension travel, but for nitro newcomers who just want to bash with a stylish machine they built themselves, the Wild Dodge Ram and Baja Beetle QRC trucks offer a pleasant build and good performance in stylish, high– riding package.
1185 Stanford Ct., Anaheim, CA 92805; (714) 978-1895;
distributed by Great Planes Model Distributors, 2904 Research Rd-,
P.O. Box 9021, Champaign, IL 61826-9021; (800) 682-8948;
distributed by Great Planes Model Distributors, P.O. Box 9021, Champaign, IL 61826-9021; (800) 682-8948; www.kyosho.com.
Copyright Air Age Publishing Dec 2001
Provided by ProQuest Information and Learning Company. All rights Reserved