Tamiya takes its shaft chassis from basic to ballistic by Greg Vogel
If you've been into the hobby a while, you'll remember that, with the TA series, Tamiya' pioneered touring cars and their shaft-drive technology. As belt-drive cars became popular, Tamiya responded with the TA-03 and its latest top-of-the-line competition tourer, the TA-04 Pro. Tamiya never gave up on shafts, however, and the system remains the drive train of choice for its 4WD vehicles. This is evident in the company's latest (and very competitive) super-scale nitro car, the TGR and the wellestablished TGX, TG-10, TL-01 and TB-01 platforms. The TB-01 is particularly interesting; it was initially offered as a rally car, but dedicated Tamiyaphiles soon discovered it had real racing potential, and Tamiya now offers a full line of race-oriented hop-ups for it.
It seems Tamiya wasn't satisfied with merely hopping up the TB-01 and has designed an all-new car-- the TB Evolution-around its shaft-drive system. The limited-release Evo is much more than a TB-01 with some optional parts; it has some TGR in its bloodline and obviously seems competitive. But as good as a car looks, the racetrack is always the real test. So let's check it out.
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KIT FEATURES
Chassis. The TB Evo has a double-deck chassis with both plates cut from woven carbon-fiber. The lower chassis plate is slotted to hold all 6 cells low on the right side, and molded battery cups with a carbonfiber hold-down strap keep the cells in place (there are also small slots for strapping tape if you want to save weight by omitting the battery hold-down). The left side of the chassis is home to the motor and all the electronics, and the area under the motor has been cut away, so the motor sits almost flush with the chassis' bottom. Even the gearboxes get the low-- CG treatment; small openings allow them to poke through the chassis and, of course, the holes on the bottom plate have been countersunk.
The top deck spans the chassis' length, and it's bolted to the front and rear bulkheads, the motor mount, the steering posts and an aluminum center post. By bolting the plate to these areas, Tamiya provides a very rigid platform with almost no noticeable flexing.
A foam bumper is captured between an upper and a lower plate. This prevents the bumper from folding over in a crash and allows it to do its job.
* Drive train. Although the Evo is shaft-driven like its TB-01 precursor, the drive train is almost totally new. The rear end is equipped with a ball differential like the one used on the TG-10, but a lightweight plastic bevel-diff gear replaces the TG-10's cast-- aluminum gear. To reduce rotating mass, the differential halves are made of light machined aluminum instead of cast aluminum. A plastic bevel pinion is mated with the diff inside the gear case, which is borrowed from the TGR. Up front, a torque splitter (also known as a one-way diff) is used in place of a conventional diff. It's built into a TB-01 cliff case held in another TGR gearbox. The TGR case is unique in that its halves aren't bolted together; instead, a ring slides over the area that encloses the bevel pinion gear bearings and prevents the case from splitting. To hold the case's outdrive portions together, they are wedged between the bulkheads.
An aluminum shaft with a steel rear tip sends power to the front and rear gearboxes. The steel tip is on the spur gear end where the pin slides through the shaft to hold the gear; the steel construction prevents the pin from stretching the hole. The spur is a 0.4 module (metric 64-pitch) and a kit-specific part; no standard gear adapter is offered, so only Tamiya spur gears and metric pinions can be used. I'm glad to say Tamiya has you covered: three 88-tooth and three 72-tooth spurs are supplied.
The drive assembly runs on rubber-sealed ball bearings, and universal axles drive the front and rear wheels. The axles aren't drilled for Tamiya's usual crosspins; instead, they are splined for metal drive hexes.
The motor plate is machined from lightweight aluminum that's anodized in a light gray and has a washer plate that the motor screws go through to hold the motor. Although the plate looks badass, it's very hard to reach the screws unless you have a ballhex driver. Even with the ball driver, it's hard to get to the screws after the car has been assembled. Tamiya supplies a black heatsink to cool the motor, and a 35-tooth pinion is also standard equipment.
* Suspension. The Evo's chassis is wider than the standard TB-01's, and its arms are longer than the standard car's, too. The arms run deeper into the wheels to improve the car's stability and handling; they are very stiff and have a matte finish that looks more raceworthy than the shiny gloss of other Tamiya kits' parts. Believe it or not, I had to drill holes in the arms for down-stop screws. I don't think I've ever had to do any hand-fitting on a Tamiya car before. You'll find stout rear hubs, hub carriers and steering knuckles at the ends of the arms, but you won't find any screw-in hinge pins. Like Tamiya's previous pro-car offerings, the Evo uses E-clip hinge pins to hold the suspension pieces together.
Machine tool basics: Part 2
This second installment of our series looks at key machine-tool elements and addresses the tool, the toolholder, and machine control.
The cutting action in a machine tool when milling and drilling involves the spindle, toolholder, and tools.
Spindle Design
Spindles, which secure the tool and its holder, are key in determining machine tool accuracy. In early machine tools, the spindles were simple bearing-- mounted shafts driven by a constant-speed electric motor, achieving different speeds through belts and gears. Operators changed spindle speed by shifting gears or moving belts to and from various pulleys.
As drive motors achieved higher torque and were designed to operate at variable speeds, belt and gear-driven systems began to wane in popularity, but both are still used. Stronger, longer-wearing, quieter belt and gear-- drive designs have been developed. Variable-speed direct drive, or integral-- motor spindles have replaced geared spindles for high-speed applications. At the same time, spindles with planetary gear systems, much like a car's automatic transmission, are now used to provide a wide torque output.
Three important variables in spindle design are the type of bearing, bearing placement, and drive motor.
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Spindle bearings. Spindles have from one to four sets of bearings. The most common bearing configuration on a spindle is one pair back to back in front, and a floating pair or single unit in back. The configuration depends largely upon the balance between axial and radial load, or whether there is an integral, belt, or gear drive.
Although most bearings use steel balls, hybrid bearings with ceramic balls and steel races are gaining favor. Ceramic balls are about 60% lighter than steel units, and so have less inertia and cause less wear. The lighter weight allows spindle shafts to turn from 30 to 50% faster. Ceramic balls are also significantly more expensive than steel.
There are other alternatives to ball bearings depending on the application, performance specifications, and the allowable cost.
Air bearings are used for light, very high-- speed loads such as small drills and high-precision polishing. Air spindles, which operate at 250,000 rpm, carry small tools, just several millimeters in diameter, and do light cuts. They can be used on hardened steels and can produce a mirror finish, eliminating EDM in some cases.
Magnetic bearings suspend the spindle shaft in a frictionless magnetic field, and are used at speeds of more than 40,000 rpm. The main problems are control, complexity, and cost. In the more distant future, superconducting bearings may be practical.
For slower, high-precision operations, hydrodynamic and hydrostatic bearings, can be used. Speed is limited due to fluid shear to slower speeds, such as are employed in some precision grinding operations.
Bearing placement. Most bearings used in spindles employ angular contact, which is the angle between the ball-to-face contact line and a plane through the ball centers perpendicular to the bearing axis. It is usually 12 to 25 deg. The smaller the contact angle, the greater the radial load-carrying ability. The greater the contact angle, the greater the axial load. Thus, choosing the correct bearing is a compromise. For example, in drilling, a very high vertical load operation might require an angle of 25 deg, while milling can be carried out at 15 deg.
The amount of preload placed on the bearing during assembly is important, particularly at speeds over 3000 rpm. At these speeds, temperature becomes an issue, and it is important that there is enough preload to compensate for thermal expansion. Preload settings are based on a combination of maximum speed and maximum cutting forces, plus the type of bearing.
Proper sealing of the bearing is essential when reliability and maintainability are important. Many spindle failures are the result of coolant, moisture, or other materials getting into the bearing. Foreign fluids degrade the lubricant, and solids can spall the raceway and bearings. Sealing problems reportedly cause more than half of the field problems encountered. Machine wrecks are the other major cause of spindles not getting to their design life.
Motor evolution. Motor technology has come a long way, particularly in the ability to get more horsepower from a smaller package. Initially, spindle motors were simple induction motors used with gearboxes and drive belts. Later there was a shift to dc units that delivered more torque. Then, in the 1980s, there was a transition to ac for many applications. The ac motors offered higher performance, higher speed, and fewer wearing parts, and don't employ electromechanical commutation. Ratings range from 5 to 15 hp. These motors can run at a fixed torque with a wide constant-horsepower range.
The cutting action in a machine tool when milling and drilling involves the spindle, toolholder, and tools.
Spindle Design
Spindles, which secure the tool and its holder, are key in determining machine tool accuracy. In early machine tools, the spindles were simple bearing-- mounted shafts driven by a constant-speed electric motor, achieving different speeds through belts and gears. Operators changed spindle speed by shifting gears or moving belts to and from various pulleys.
As drive motors achieved higher torque and were designed to operate at variable speeds, belt and gear-driven systems began to wane in popularity, but both are still used. Stronger, longer-wearing, quieter belt and gear-- drive designs have been developed. Variable-speed direct drive, or integral-- motor spindles have replaced geared spindles for high-speed applications. At the same time, spindles with planetary gear systems, much like a car's automatic transmission, are now used to provide a wide torque output.
Three important variables in spindle design are the type of bearing, bearing placement, and drive motor.
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Spindle bearings. Spindles have from one to four sets of bearings. The most common bearing configuration on a spindle is one pair back to back in front, and a floating pair or single unit in back. The configuration depends largely upon the balance between axial and radial load, or whether there is an integral, belt, or gear drive.
Although most bearings use steel balls, hybrid bearings with ceramic balls and steel races are gaining favor. Ceramic balls are about 60% lighter than steel units, and so have less inertia and cause less wear. The lighter weight allows spindle shafts to turn from 30 to 50% faster. Ceramic balls are also significantly more expensive than steel.
There are other alternatives to ball bearings depending on the application, performance specifications, and the allowable cost.
Air bearings are used for light, very high-- speed loads such as small drills and high-precision polishing. Air spindles, which operate at 250,000 rpm, carry small tools, just several millimeters in diameter, and do light cuts. They can be used on hardened steels and can produce a mirror finish, eliminating EDM in some cases.
Magnetic bearings suspend the spindle shaft in a frictionless magnetic field, and are used at speeds of more than 40,000 rpm. The main problems are control, complexity, and cost. In the more distant future, superconducting bearings may be practical.
For slower, high-precision operations, hydrodynamic and hydrostatic bearings, can be used. Speed is limited due to fluid shear to slower speeds, such as are employed in some precision grinding operations.
Bearing placement. Most bearings used in spindles employ angular contact, which is the angle between the ball-to-face contact line and a plane through the ball centers perpendicular to the bearing axis. It is usually 12 to 25 deg. The smaller the contact angle, the greater the radial load-carrying ability. The greater the contact angle, the greater the axial load. Thus, choosing the correct bearing is a compromise. For example, in drilling, a very high vertical load operation might require an angle of 25 deg, while milling can be carried out at 15 deg.
The amount of preload placed on the bearing during assembly is important, particularly at speeds over 3000 rpm. At these speeds, temperature becomes an issue, and it is important that there is enough preload to compensate for thermal expansion. Preload settings are based on a combination of maximum speed and maximum cutting forces, plus the type of bearing.
Proper sealing of the bearing is essential when reliability and maintainability are important. Many spindle failures are the result of coolant, moisture, or other materials getting into the bearing. Foreign fluids degrade the lubricant, and solids can spall the raceway and bearings. Sealing problems reportedly cause more than half of the field problems encountered. Machine wrecks are the other major cause of spindles not getting to their design life.
Motor evolution. Motor technology has come a long way, particularly in the ability to get more horsepower from a smaller package. Initially, spindle motors were simple induction motors used with gearboxes and drive belts. Later there was a shift to dc units that delivered more torque. Then, in the 1980s, there was a transition to ac for many applications. The ac motors offered higher performance, higher speed, and fewer wearing parts, and don't employ electromechanical commutation. Ratings range from 5 to 15 hp. These motors can run at a fixed torque with a wide constant-horsepower range.
New Speed Reducer/Increaser Launched - Rj Link International Inc - Brief Article
Rj Link International Inc. has introduced a new off-highway gearbox that will expand the Rockford, Ill., manufacturer's range of off-highway powertrain components. Founded in 1993, Link manufactures standard and custom gearboxes and components for a variety of off-highway uses, as well as having a contract machining business primarily used by a number of construction equipment manufacturers.
The product range includes engine-mounted and freestanding speed reducers and increasers, as well as hydraulic pump drives, transfer cases, multiple speed gearboxes and right angle drives.
The newest addition to Rj Link line is the model D144 gearbox. The box, which can be used either as reducer or increaser, has an input capacity of 600 hp at 1800 rpm and ratios of 1.2:1 through 3.0:1 in either engine or anti-engine rotation. The D144 is targeted at uses such as mud pumps, rock crushers, tub grinders, wood chippers, air and/or gas compressors and generator sets.
The D144 gearbox has a cast iron housing and uses hardened helical gears and tapered roller bearings. According to Rod Link, president of Rj Link, one of the key design features of the D144 is the use of helical gears that are splined to shafts. This means no keyways and reduced noise and heat, while adding strength and durability to the design, he said.
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The gearbox is designed to be direct mounted to a diesel engine via an integral bell housing, though it can also be adapted for remote or independent mounting. The input shaft can be configured for a mechanical clutch, air clutch or a flywheel coupling. The standard output shaft is 4 in. x 9 in. long, with other styles available.
The launch of the D144 continues a recent move by Rj Link to expand the standard product side of the business, which works in parallel with the company's custom gearbox business, products typically built on a proprietary basis for a specific equipment manufacturer.
Rod Link said the company pursues applications up to about 1000 hp. Other gearboxes manufactured by Rj Link are used in applications such as construction equipment brooms, grain handling equipment, orchard sprayers, air compressors, truck-mounted pump drives, concrete saws, snowblowers and snow grooming equipment. All are manufactured at Rj Link's 15,000 sq.ft. facility, which was recently ISO 9001 certified. The plant features vertical and horizontal CNC machining centers, CNC lathes, CNC gear hobbing, gear shaping and horizontal broaching capability, which allows the company to handle single piece prototype, as well as higher volume machining operations, Rod Link said.
Among the other standard products in the Rj Link line is the model D101, an aluminum case gearbox that has an input capacity of 240 hp at 1000 rpm with a 1.8:1 ratio, or 215 hp at 1000 rpm with a 4.0:1 ratio. Hardened helical gears and tapered roller bearings are used.
The model D105 has input capacities of 425 hp and 375 hp at 1800 rpm with 1.2:1 and 3.0:1 ratios respectively as either a speed increaser or reducer. The D106 is a two-speed gearbox, with standard ratios from 1.0:1 and 4.0:1, and input capacities of 55 hp or 190 hp at 1000 rpm. Both the D105 and D106 gearboxes have cast iron housings. The D119 is a cast iron drop-box with an input capacity of 375 hp at 1800 rpm and 1:1 standard ratios.
The D131 is a cast iron split-shaft transfer case with 1:1 ratios and an input capacity of 500 lip at 1800 rpm with 1500 lb.ft. torque to the top shaft and 1500 lb.ft. on the straight through drive.
Among the more specialized boxes Rj Link has designed and manufactured is a proprietary planetary drive with an input capacity of 600 lip at 1800 rpm, that uses hardened spur gears and has available ratios of 5:1 and 6:1.
The product range includes engine-mounted and freestanding speed reducers and increasers, as well as hydraulic pump drives, transfer cases, multiple speed gearboxes and right angle drives.
The newest addition to Rj Link line is the model D144 gearbox. The box, which can be used either as reducer or increaser, has an input capacity of 600 hp at 1800 rpm and ratios of 1.2:1 through 3.0:1 in either engine or anti-engine rotation. The D144 is targeted at uses such as mud pumps, rock crushers, tub grinders, wood chippers, air and/or gas compressors and generator sets.
The D144 gearbox has a cast iron housing and uses hardened helical gears and tapered roller bearings. According to Rod Link, president of Rj Link, one of the key design features of the D144 is the use of helical gears that are splined to shafts. This means no keyways and reduced noise and heat, while adding strength and durability to the design, he said.
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The gearbox is designed to be direct mounted to a diesel engine via an integral bell housing, though it can also be adapted for remote or independent mounting. The input shaft can be configured for a mechanical clutch, air clutch or a flywheel coupling. The standard output shaft is 4 in. x 9 in. long, with other styles available.
The launch of the D144 continues a recent move by Rj Link to expand the standard product side of the business, which works in parallel with the company's custom gearbox business, products typically built on a proprietary basis for a specific equipment manufacturer.
Rod Link said the company pursues applications up to about 1000 hp. Other gearboxes manufactured by Rj Link are used in applications such as construction equipment brooms, grain handling equipment, orchard sprayers, air compressors, truck-mounted pump drives, concrete saws, snowblowers and snow grooming equipment. All are manufactured at Rj Link's 15,000 sq.ft. facility, which was recently ISO 9001 certified. The plant features vertical and horizontal CNC machining centers, CNC lathes, CNC gear hobbing, gear shaping and horizontal broaching capability, which allows the company to handle single piece prototype, as well as higher volume machining operations, Rod Link said.
Among the other standard products in the Rj Link line is the model D101, an aluminum case gearbox that has an input capacity of 240 hp at 1000 rpm with a 1.8:1 ratio, or 215 hp at 1000 rpm with a 4.0:1 ratio. Hardened helical gears and tapered roller bearings are used.
The model D105 has input capacities of 425 hp and 375 hp at 1800 rpm with 1.2:1 and 3.0:1 ratios respectively as either a speed increaser or reducer. The D106 is a two-speed gearbox, with standard ratios from 1.0:1 and 4.0:1, and input capacities of 55 hp or 190 hp at 1000 rpm. Both the D105 and D106 gearboxes have cast iron housings. The D119 is a cast iron drop-box with an input capacity of 375 hp at 1800 rpm and 1:1 standard ratios.
The D131 is a cast iron split-shaft transfer case with 1:1 ratios and an input capacity of 500 lip at 1800 rpm with 1500 lb.ft. torque to the top shaft and 1500 lb.ft. on the straight through drive.
Among the more specialized boxes Rj Link has designed and manufactured is a proprietary planetary drive with an input capacity of 600 lip at 1800 rpm, that uses hardened spur gears and has available ratios of 5:1 and 6:1.
Tamiya Avante
The year was 1988, and the hottest car, on the market was the Tamiya Avante. Four-wheel-drive offroad was booming, and Tamiya introduced its technological master- " piece with the hope that it would take the world by storm. For many, the Avante was the ultimate car-the pinnacle of RC tech when buggies reigned supreme.
Now, 13 years after the original Avante was reviewed in the September 1988 issue of Radio Control Car Action, we look back at a car that was ahead of its time. JP's Hobbies and Raceway in Ansonia, CT, has a pristine Avante on display. and they let me borrow it for a flashback to the years before Chain-drive was still popular for four wheelers back, in 88, that the Avante used an advanced shaft-drive system with the motor mounted parallel to the drive train. The front and rear gearboxes are equipped with scaled gear cliffs, and the spur gear features a ball differential; this makes the Av ante a triple cliff car. The front and rear gearboxes are fairly elaborate and use a combination of straight-cut and beveled gears.
Shooting the Avante really took us back in time, and we found ourselves getting nostalgic for the good old days-even though RC stuff is a lot better now! It's nice to look back, but don't get stuck in a time warp. You know you're stuck in 1988 when ... Your "digital" charger has a 15-minute timer.
You just over-charged your SCE pack. The only "TC" you know about is the guy who flew the helicopter on "Magnum PI."
You put belt drive on your RC10 ... ... after you dialed in the A&L trailing arms.
Not any more flashback fodder? Log onto cccaraction.com, and share it with the est of us old folks.
QUICK-RELEASE WHEELS
The Avante's hubcaps are actually integral mounting nuts. Pop-up tabs are used to unscrew the hubcap and remove the wheel. When the tabs are flipped down, they fit into the rim to prevent the hubcap from backing out.
HI-CAP DAMPERS
The Avante's aluminum-body, double-0-ring shocks are as smooth as any modern units and are precisely machined, There's nothing dated about them at all!
THROW-BACK ELECTRONICS
This is Avante sports gear straight from '88. Check out the pager-size receiver and extra-long antenna-nice. The Futaba ESC and the Trinity Monster Horse Power motor are classics,
FIBERGLASS CHASSIS
The arrowhead-shaped top deck looks pretty, but the main chassis is little more than a straight slab of fiberglass. The rear transmission sits on top of the lower deck, but the front tranny is actually a structural chassis component that is cantilevered off the front of the lower deck. The Avante accepted 6- or 7-cell packs and held the battery very close to the main chassis' centerline. A plastic retainer held in place by a body clip kept the pack in place.
MULTI-LINK SUSPENSION
What looks like a big mess is actually a 3-link suspension that had just as much adjustability in the front as in the rear: camber and toe-in were infinitely adjustable via thick aluminum turnbuckles. Note the spidery, cast steering hubs, universal-joint axles and the tiny pivoting castings that are joined by a urethane bushing. The pivoting castings allowed the front suspension to flex back in a crash rather than bend or break. The laydown shock position did not require a shock tower; instead, short standoffs held the shocks and, like the rear shocks. were braced by a threaded rod.
TRIPLE-BELLCRANK STEERING
The Avante's unconventional steering-servo placement called for an equally unconventional linkage. It worked; the extra bellcrank eliminated the need for an extra-long wire link at the servo, and the rigid aluminum bracket operated the primary bell
cranks smoothly with equal throw in both directions.
ROBOTECH BODY
The Avante's body is a good example of Japanese "sci-fi deco" at its best. The curvaceous shell looks ready to go into hyperspace with its dual "intakes" and uncaged bubble cockpit. A separate undertray is clipped beneath the chassis. Removing both pieces was a hassle; three clips hold the undertray, and the main body could be peeled off only after two body clips and both suspension braces were popped off.
`CHOCOLATE-CHIP" SPIKED TIRES
Back in 1988, soft compound tires did not exist hard, plasticky tires and spiky knobs ruled the day. The Avante wore spikes that were shaped like chocolate chips and hooked up fairly well on loose surfaces.
Tamiya cars were (and are) notable for their high-quality molding, detailed manuals and great box art, but the vintage machines had a little something extra that made them uniquely Tamiya: wacky wing slogans. Here are some of the classics; they probably seemed like a good idea in Japanese, but it's all in the translation ....
AVANTE-Being Nuts is Neat!
HORNET-Anytime Baby!
VANQUISH-Up and Away!
GRASSHOPPER 2-I'm Hopping Mad!
STRIKER-Get Rough!
FALCON-Born to be Wild!
FROG-No Guts, No Glory
EGRESS-Way Out Running
SUPER CHAMP-Go for It!
MAD CAP-Never Give Up
TERRA SCORCHER-Flying High
ASTUTE-Awesome!
Tamiya re-released the Wild Willy and XR-311, and the Bruiser came back briefly as the Mountaineer. Is there any hope for an Avante comeback? Chances are slim; none of its parts still exist as components of current Tamiya vehicles, and it would be very expensive to bring back all those molded and cast parts. If you want an Avante, check out eBay. But if you would settle for a Manta Ray-the historic 4WD tub-chassis buggy that gave life to the TA01 touring car and the entire touring car boom-- you're in luck; Tamiya plans to rerelease the Manta Ray as an Expert Built ready-to-run! E
Now, 13 years after the original Avante was reviewed in the September 1988 issue of Radio Control Car Action, we look back at a car that was ahead of its time. JP's Hobbies and Raceway in Ansonia, CT, has a pristine Avante on display. and they let me borrow it for a flashback to the years before Chain-drive was still popular for four wheelers back, in 88, that the Avante used an advanced shaft-drive system with the motor mounted parallel to the drive train. The front and rear gearboxes are equipped with scaled gear cliffs, and the spur gear features a ball differential; this makes the Av ante a triple cliff car. The front and rear gearboxes are fairly elaborate and use a combination of straight-cut and beveled gears.
Shooting the Avante really took us back in time, and we found ourselves getting nostalgic for the good old days-even though RC stuff is a lot better now! It's nice to look back, but don't get stuck in a time warp. You know you're stuck in 1988 when ... Your "digital" charger has a 15-minute timer.
You just over-charged your SCE pack. The only "TC" you know about is the guy who flew the helicopter on "Magnum PI."
You put belt drive on your RC10 ... ... after you dialed in the A&L trailing arms.
Not any more flashback fodder? Log onto cccaraction.com, and share it with the est of us old folks.
QUICK-RELEASE WHEELS
The Avante's hubcaps are actually integral mounting nuts. Pop-up tabs are used to unscrew the hubcap and remove the wheel. When the tabs are flipped down, they fit into the rim to prevent the hubcap from backing out.
HI-CAP DAMPERS
The Avante's aluminum-body, double-0-ring shocks are as smooth as any modern units and are precisely machined, There's nothing dated about them at all!
THROW-BACK ELECTRONICS
This is Avante sports gear straight from '88. Check out the pager-size receiver and extra-long antenna-nice. The Futaba ESC and the Trinity Monster Horse Power motor are classics,
FIBERGLASS CHASSIS
The arrowhead-shaped top deck looks pretty, but the main chassis is little more than a straight slab of fiberglass. The rear transmission sits on top of the lower deck, but the front tranny is actually a structural chassis component that is cantilevered off the front of the lower deck. The Avante accepted 6- or 7-cell packs and held the battery very close to the main chassis' centerline. A plastic retainer held in place by a body clip kept the pack in place.
MULTI-LINK SUSPENSION
What looks like a big mess is actually a 3-link suspension that had just as much adjustability in the front as in the rear: camber and toe-in were infinitely adjustable via thick aluminum turnbuckles. Note the spidery, cast steering hubs, universal-joint axles and the tiny pivoting castings that are joined by a urethane bushing. The pivoting castings allowed the front suspension to flex back in a crash rather than bend or break. The laydown shock position did not require a shock tower; instead, short standoffs held the shocks and, like the rear shocks. were braced by a threaded rod.
TRIPLE-BELLCRANK STEERING
The Avante's unconventional steering-servo placement called for an equally unconventional linkage. It worked; the extra bellcrank eliminated the need for an extra-long wire link at the servo, and the rigid aluminum bracket operated the primary bell
cranks smoothly with equal throw in both directions.
ROBOTECH BODY
The Avante's body is a good example of Japanese "sci-fi deco" at its best. The curvaceous shell looks ready to go into hyperspace with its dual "intakes" and uncaged bubble cockpit. A separate undertray is clipped beneath the chassis. Removing both pieces was a hassle; three clips hold the undertray, and the main body could be peeled off only after two body clips and both suspension braces were popped off.
`CHOCOLATE-CHIP" SPIKED TIRES
Back in 1988, soft compound tires did not exist hard, plasticky tires and spiky knobs ruled the day. The Avante wore spikes that were shaped like chocolate chips and hooked up fairly well on loose surfaces.
Tamiya cars were (and are) notable for their high-quality molding, detailed manuals and great box art, but the vintage machines had a little something extra that made them uniquely Tamiya: wacky wing slogans. Here are some of the classics; they probably seemed like a good idea in Japanese, but it's all in the translation ....
AVANTE-Being Nuts is Neat!
HORNET-Anytime Baby!
VANQUISH-Up and Away!
GRASSHOPPER 2-I'm Hopping Mad!
STRIKER-Get Rough!
FALCON-Born to be Wild!
FROG-No Guts, No Glory
EGRESS-Way Out Running
SUPER CHAMP-Go for It!
MAD CAP-Never Give Up
TERRA SCORCHER-Flying High
ASTUTE-Awesome!
Tamiya re-released the Wild Willy and XR-311, and the Bruiser came back briefly as the Mountaineer. Is there any hope for an Avante comeback? Chances are slim; none of its parts still exist as components of current Tamiya vehicles, and it would be very expensive to bring back all those molded and cast parts. If you want an Avante, check out eBay. But if you would settle for a Manta Ray-the historic 4WD tub-chassis buggy that gave life to the TA01 touring car and the entire touring car boom-- you're in luck; Tamiya plans to rerelease the Manta Ray as an Expert Built ready-to-run! E
Tamiya TGR
Tamiya is well known for designing innovative and true-to-scale RC vehicles, but lately, its engineering efforts have seemed to be focused more on the competitive end of the RC spectrum. As a result, Tamiya recently released several vehicles that not only look good, but they have the necessary ingredients for serious competition, too. The subject of this Track Test-the Tamiya TGR-happens to be one of them. One look at its low-slung, black-on-black chassis is all it takes to realize that this new, super-class entry is designed to do one thing: intimidate the competition. As an editor of Radio Control Car Action, however, I've learned never to judge a book by its cover, so off to the track I went. Does the Tamiya TGR have what it takes to be a predator in the growing super touring class? Let's find out. Chassis. The TGR's narrow, 2.Smm-thick duralumin chassis resembles the chassis plates that are used on 1/8-scale, .21-powered on-road vehicles. It places the weight of all the drive-train components and onboard electronics closer to the chassis centerline for improved handling. The screwholes are completely countersunk, so all the screws can be mounted flush with the chassis, and openings under the front and rear diff cases, the fuel tank, engine, swaybars and 2-speed allow these components to be mounted with the lowest possible center of gravity (CG).
The long and narrow, 2mm-thick graphite upper deck is mounted on the front and rear suspension assemblies and neatly houses the onboard electronics. Graphite is lighter and more rigid than aluminum and plastic, and that makes it a welcome addition to any racecar. A racing-style front bumper with a urethane body protector and a molded transponder mount are also on the list of hot features.
* Drive train. The TGR's shaft-drive system is similar to the drive train used on the TGX-Mk. 1, but the TGR has lighter, more compact diff cases and smaller, cast-alloy ring gears that allow the diffs to be mounted lower on the chassis. In addition, both the front and rear diffs-and the rest of the drive train-are offset 7mm to the right side of the chassis to allow the engine and fuel tank to be mounted as close as possible to the chassis centerline.
The cast-alloy internal bevel and spider gears inside the diffs have large teeth that look as though they should be able to handle plenty of horsepower. Tamiya supplies a thick grease to slow down the diff action, and it's so effective that I'm going to order more of it to use on my other gear-diff-equipped cars.
A single lightweight aluminum propeller shaft joins the two gearboxes and provides full-time 4WD. A newly designed, adjustable 2-speed transmission is attached to the rear gearbox and is joined to the front by the main propeller shaft. Instead of using a locking "fingers"-type centrifugal shifting system, which is common on many other 2-speed-equipped vehicles, Tamiya adopted an adjustable 2-shoe centrifugal clutch system to engage the shift point. The Tamiya 2-speed transmission shifts very smoothly and should require less maintenance than conventional 2-speed systems.
The TGR features the same disc brake system as is found on the TGX-Mk.1. Two cam-actuated steel brake pads pinch the 3mm-thick fiber-composite disc brake that's keyed to the 2-speed transmission's drive hub. Regardless of which servo you use, this braking system should provide smooth, controlled braking without fading. Front and rear steel dogbones and serrated axles with aluminum hex hubs complete the drive train (no more drive pins; way to go, Tamiya!). I was a little bummed that the TGR doesn't include universal axles for the front, but this is made up for by the fact that the entire drive train-including the wheels-spins on Tamiya's high-quality rubber-sealed bearings.
e Suspension. The TGR features an all-new racing suspension that includes extra-long front and rear lower suspension arms and unique molded, telescoping upper links. The lower suspension arms capture the front "C" carriers and rear hub carriers for added strength, and the entire suspension pivots smoothly on stainless-steel hinge pins. Setscrews threaded into the lower front and rear suspension arms allow down-stop travel adjustment. The two-piece molded upper links have corresponding male and female halves that are joined with threaded rods. The downside to this system is that you have to unfasten one end of the molded upper links to make camber adjustments, but the molded upper links are more rigid than standard camber links, and that makes up for the slight inconvenience.
Tamiya's excellent aluminum-body, oil-filled shocks with double O-ring seals, silicone diaphragms and Teflon pistons and shaft guides are standard issue. The shocks are black-anodized to match the rest of the car's components, and they provide exceptionally smooth performance. The front shocks snap onto ball joints that are installed on the suspension arms and front bulkhead. The rear shocks are also attached to the suspension arms with ball joints, but the upper portions are attached to a graphite shock tower. To provide more progressive damping, all four shocks are mounted in a laydown position, and stiff front and medium rear springs are included to balance out the car's handling. Also included are front and rear ball-and-cup swaybars that can be adjusted to reduce body roll and divert traction to the front or rear as necessary
The long and narrow, 2mm-thick graphite upper deck is mounted on the front and rear suspension assemblies and neatly houses the onboard electronics. Graphite is lighter and more rigid than aluminum and plastic, and that makes it a welcome addition to any racecar. A racing-style front bumper with a urethane body protector and a molded transponder mount are also on the list of hot features.
* Drive train. The TGR's shaft-drive system is similar to the drive train used on the TGX-Mk. 1, but the TGR has lighter, more compact diff cases and smaller, cast-alloy ring gears that allow the diffs to be mounted lower on the chassis. In addition, both the front and rear diffs-and the rest of the drive train-are offset 7mm to the right side of the chassis to allow the engine and fuel tank to be mounted as close as possible to the chassis centerline.
The cast-alloy internal bevel and spider gears inside the diffs have large teeth that look as though they should be able to handle plenty of horsepower. Tamiya supplies a thick grease to slow down the diff action, and it's so effective that I'm going to order more of it to use on my other gear-diff-equipped cars.
A single lightweight aluminum propeller shaft joins the two gearboxes and provides full-time 4WD. A newly designed, adjustable 2-speed transmission is attached to the rear gearbox and is joined to the front by the main propeller shaft. Instead of using a locking "fingers"-type centrifugal shifting system, which is common on many other 2-speed-equipped vehicles, Tamiya adopted an adjustable 2-shoe centrifugal clutch system to engage the shift point. The Tamiya 2-speed transmission shifts very smoothly and should require less maintenance than conventional 2-speed systems.
The TGR features the same disc brake system as is found on the TGX-Mk.1. Two cam-actuated steel brake pads pinch the 3mm-thick fiber-composite disc brake that's keyed to the 2-speed transmission's drive hub. Regardless of which servo you use, this braking system should provide smooth, controlled braking without fading. Front and rear steel dogbones and serrated axles with aluminum hex hubs complete the drive train (no more drive pins; way to go, Tamiya!). I was a little bummed that the TGR doesn't include universal axles for the front, but this is made up for by the fact that the entire drive train-including the wheels-spins on Tamiya's high-quality rubber-sealed bearings.
e Suspension. The TGR features an all-new racing suspension that includes extra-long front and rear lower suspension arms and unique molded, telescoping upper links. The lower suspension arms capture the front "C" carriers and rear hub carriers for added strength, and the entire suspension pivots smoothly on stainless-steel hinge pins. Setscrews threaded into the lower front and rear suspension arms allow down-stop travel adjustment. The two-piece molded upper links have corresponding male and female halves that are joined with threaded rods. The downside to this system is that you have to unfasten one end of the molded upper links to make camber adjustments, but the molded upper links are more rigid than standard camber links, and that makes up for the slight inconvenience.
Tamiya's excellent aluminum-body, oil-filled shocks with double O-ring seals, silicone diaphragms and Teflon pistons and shaft guides are standard issue. The shocks are black-anodized to match the rest of the car's components, and they provide exceptionally smooth performance. The front shocks snap onto ball joints that are installed on the suspension arms and front bulkhead. The rear shocks are also attached to the suspension arms with ball joints, but the upper portions are attached to a graphite shock tower. To provide more progressive damping, all four shocks are mounted in a laydown position, and stiff front and medium rear springs are included to balance out the car's handling. Also included are front and rear ball-and-cup swaybars that can be adjusted to reduce body roll and divert traction to the front or rear as necessary
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