WORLDS WEAPON: Kyosho Inferno MP-7.5 Yuichi Kanai Edition III
IN THE WORLD OF 1/8-SCALE BUGGIES, the Kyosho Inferno series is legendary, thanks to its six consecutive IFMAR World Championship titles. The original Inferno spawned the MP-5, MP-6 and the most successful of all the Infernos-the MP-7.5. Yuichi Kanai is the designer of the world champion 7.5, and in 2000, Yuichi actually won the title with the car he designed. To commemorate the win, Kyosho released a “Kanai Edition” MP-7.5. The signature model evolved into the Kanai II (which Greg Oegani drove to victory at the 2002 IFMAR Worlds), and for the 2004 event, Yuichi has further honed the big buggy into the Inferno MP-7.5 Yuichi Kanai Edition III. With less weight, greater durability and increased suspension travel, the Kanai III is the ultimate Inferno and just may be the best buggy on the planet; we’ll find out in August at the 2004 Worlds in San Paolo, Brazil. But you’ll only have to wait as long as it takes to turn the page to get under the hood of the Kanai III.
CHASSIS. The Kanai III chassis is 3mm 7075 hard-anodized aluminum, which is as tough as 1/8-scale buggy chassis get. Like all MP-7.5S, the chassis has “blisters” punched into its underside that allow the differentials to sit a millimeter or so lower than they otherwise could, but unlike other MP-7.5S, the top of the Kanai III chassis is strategically milled to shave off precious grams; according to Kyosho, 1.4 ounces (40 grams) has been pared thanks to the process. A few more grams are trimmed by the liberal use of titanium hardware; more than half the kit’s screws are made of everyone’s favorite wonder metal.
The rest of the chassis features are standard MP-7.5 stuff. The radio box has separate receiver and battery compartments, the 2mm radio tray is secured by turned-aluminum standoffs, and rod braces bolster the gearbox/suspension assemblies.
DRIVE TRAIN. Kyosho’s Traction Control Differential (TCD) has been a staple of the Kanai series and returns with the III model. Unlike the Kanai II, which had TCDs front and center, the Kanai III only uses the TCD up front. The diff uses steel reinforcement plates to prevent the four, fine-pitch, hardened-steel spider gears from separating under load. The center and rear diffs use cast-alloy gear sets with coarser teeth. All three diffs are sealed, of course, so their action can be adjusted by varying diff-fluid viscosity, and the center diffs spur gear is steel. Universal-joint drive shafts join the diffs and connect the differentials to the stub axles.
Interestingly, the Kanai III does not have a fashionable 4-rotor brake system. A pair of vented-steel rotors that are squeezed by padded calipers do all the work, and its stiff brake springs don’t have to be exchanged for sections of fuel tubing. The springs are a small touch but one that greatly increases brake feel and power. Each brake linkage is threaded, and adjustable via a knurled thumbwheel, so you can alter brake bias.
ENGINE AND ACCESSORIES. You won’t find an engine or exhaust system in the Kanai III’s box, but you will find everything you need to install them. A 3-shoe clutch with a lightweight flywheel is supplied and uses the usual mousetrap-style springs, but the shoes are made of aluminum, so they engage “harder” and wear longer. The engine mounts are machined aluminum and deeply finned to increase cooling; and they’re attached to the chassis with plates that allow you to remove and reinstall the engine without altering the gear mesh. Fuel is supplied by a standard MP-7.5 tank with the usual features: internal stone filter, molded-in spillway and cap-mounted pressure tap. An ample splashguard alongside the tank keeps fuel away from the brake system and clutch bearings during fast fill-ups.
SUSPENSION AND STEERING. The Kanai III’s shocks look like standard MP-7-5 units, but the rears are 2mm longer. That might not sound like much, but an extra 2mm at the shock eyelets translates into significantly more downtravel at the axles. The Kanai III’s suspension verges on monster truck territory, so bumpy tracks shouldn’t be a problem. Length notwithstanding, the shocks are standard Inferno stuff: aluminum bodies, heavy-duty 3.5mm shafts, bladder volume compensators, clip-on preload spacers and shaft-protecting rubber boots. The only uncool parts are the pins that hold the lower shock eyelets; they love to vibrate out. I’ll replace them with screws later.
Along with extra travel, the Kanai III’s suspension gets some extra adjustability. The kit includes two sets of front upper arms and hub carriers that let you select 20 or 22 degrees of caster, and the steering plate now has three holes for a greater range of Ackerman settings. New, heavy-duty, titanium-nitride-coated steel turnbuckles set camber and toe-in. Swaybars are standard (2.5mm front, 2.8mm rear), and the inboard hinge pins are held by 3mm aluminum plates behind the front gearbox on a machined-aluminum block, so they’ll stay put in a crash.
BODY. WHEELS AND TIRES. Make that “body and wheels,” since the kit doesn’t include tires. The body is a standard MP-7.5 shell, but for Kanai III duty, precut Lexan reinforcements are provided to strengthen the area around the body posts. The wheels are standard Inferno 10-spokers in Kanai’s trademark green, which is also the color of choice for the bi-level rear wing. Thick arms braced by aluminum standoffs hold the wing, and there are two wing-angle settings.
BUILDING & SETUP TIPS
Can we go ahead and assume that anyone with the dough and desire to pony up for a Kanai III already has some RC experience? Good. You’ll have no problem getting the kit together, although a few tips can’t hurt.
STEPS 16 TO 18. FRONT SUSPENSION. The hub carriers shown in the manual give 22 degrees of caster. If you want more aggressive steering, install the no. 305 (right) and 306 (left) carriers for the 20-degree setup.
STEP 21. BRAKED-PAD ASSEMBLY. Glue the pads to the caliper plates with Shoe-Goo or Goop. The icon in the manual says “rubber cement,” but that’s just a Japanese translation thing.
STEP 28. ENGINE INSTALL. Install the mounting pads on the chassis first, and then bolt the engine into the chassis.
STEP 34. TRANSPONDER MOUNT
The manual shows a mount for an AMB personal transponder, and that’s correct. But if you haven’t moved up to a personal transponder yet, there’s also a standard transponder mount in the box (it’s on the same parts tree as the receiver-box lids).
* Transmitter and receiver
* .21 rear-exhaust, bump-start engine with SG crank
* Tire glue
* Steering and throttle servos
* Exhaust pipe and manifold
* Glow igniter
* Starter box
* Polycarbonate paint
* Shock fluid
MODEL Inferno MP-7.5 Yuichi Kanai Edition III
DISTRIBUTED BY Great Planes Model Distributors
Varies with dealer
Wheelbase 13 in. (328mm)
Width 12.1 in. (307mm)
Total, as tested 116 02. (3,289g)
Type Double-deck plate with rod stiffeners
Material 3mm 7075 aluminum, hard-anodized main chassis with 2mm blue-anodized radio tray/braces
Type Shaft-driven full-time 4WD
Primary 46T steel spur gear/13T clutch bell
Drive shafts Steel universal joint
Differentials Sealed, 6-gear, silicone-filled; “TCD” front differential
Bearing type Rubber-sealed
Type Lower H-arm with turnbuckle camber link
Shocks Aluminum body with 3.5mm shaft and rubber shaft cover
Type Kyosho 10-spoke
Dimensions Standard 1/8 buggy; 17mm hub
ENGINE AND ACCESSORIES
Engine Not included
Exhaust system Not included
Clutch 3-shoe. aluminum shot s
Fuel tank 125cc, primerless with internal filter
RC Madness is Connecticut’s hot spot for 1/8-scale off-road racing, and it was the ideal test venue for the Kanai III. I tested the big buggy before Madness’ official opening day, so the track layout was only roughed in and was definitely on the gnarly side of the terrain spectrum-all the better to test the Kanai III’s longer tegs.
With a full tank of Trinity Platinum Blend 30-percent nitro in the tank, the Kanai III was ready to hit the starter box. The engine was already broken in and pretty much dialed after the photo shoot a week earlier, so all I had to do was drive. Easier said than done! As quickly as I could get on the gas, it was time to let off and pitch the Kanai into the first turn. The buggy would push if I overcooked it, but the limits were very high, and the steering is very neutral until the Pro-Lines can take no more. The dual swaybars keep the chassis flat despite the leggy suspension. As weight transfers rearward during corner exits, the Kanai III digs in very hard. Once the buggy was lined up, I could squeeze the trigger and practically take my hand off the wheel.
A lot of the buggies at Madness seem to be set up low and stiff to skip over bumps. It works, but they lose a lot of momentum to wheel-spin. The Kanai III was much more supple, and its suspension pumped through the rough as it put power down. The track’s deep Bobcat treads were able to buck the buggy, but you’ll never see that kind of erosion on a properly groomed track. Bumps like those you’d see in real racing were easily absorbed.
The long suspension that helped give the Kanai III its bump-eating prowess also made it a great jumper. It stayed lower and flatter than I expected (no doubt because the suspension was absorbing energy that is normally transferred to the buggy), and there was ample cush for soft landings. Every second spent in the air is a second you can’t use to put down power, so the Kanai III’s ability to jump low and keep power on the ground longer can only help lap times.
Strong brakes also cut lap times by letting you stay on the gas longer before braking for turns. The Kanai III’s brakes call into question the need for “quad” systems with four rotors. Brake feel was excellent, and wheel-locking power was always in reserve. Once the bias had been set properly and the servo endpoint had been set just shy of lockup, I could jam (he trigger the instant before a hairpin turn, and the Kanai III would hook it as if it had ABS.
A six-time world-champion buggy platform with the best factory racing gear tweaked by the designer himself. What’s not to like about the Kyosho Inferno MP-7.5 Yuichi Kanai Edition III? Just two things: the price (which is defensible given all the car has, but man, 800 bucks!) and the silly shafts that hold the lower shock eyelets (and love to vibrate out). But what’s the cost of four 3mm screws when you’re already into it for eight bills? Cost isn’t the point here. The Kanai III is a no-holds-barred racing machine; backyard bashers and price-point shoppers need not apply. Judged as such, the Kanai III is arguably as good as competition buggies get, and come August, when Team Kyosho take on the world in Brazil, they just might dispel “arguably” with a seventh world-championship title.
* Ready to race at any level; no upgrades required.
* Legendary MP-7.5 performance.
* Includes parts for 20-and 22-degree caster settings.
* You wanna play, you gotta pay; try $800 on for size.
Futaba 3PK transmitter and R203HF receiver
A world-class buggy deserves world-class radio gear, and the Futaba 3PK definitely fits the bill. The futuristic super radio has every adjustment you could ever need for racing, Including exponential, servo speed, and three timer functions, plus nitrospecific features such as idle-up and ABS braking that make the 3PK ideal for big-buggy duty. Futaba’s High Response System Is also on board for super-responsive steering and throttle feel when using digital servos.
Additional Items used to complete the Kanal III:
Futaba S9450 digital steering and throttle servos
Sirio S21BK Kanai Edition engine
OFNA spring-coupled tuned pipe and manifold
Copyright Air Age Publishing Jun 2004
Provided by ProQuest Information and Learning Company. All rights Reserved