OFNA Ultra GTP RTR

Radio Control Car Action, Jun 2001 by Gonzalez, George M

Drive train. A stout shaft-drive system provides continuous 4WD. The inline-mounted engine's clutch bell is mated with a steel, center-- mounted spur gear, and the power is transferred to the front and rear bevel-- gear differentials via steel dogbones and ring and pinion gears.

CV axles up front and steel dogbones in the rear provide the final drive, and the drive train and wheels spin on shielded ball bearings. Stopping power is provided by a stainless-steel disc brake with aluminum-and-rubber brake pads. This is essentially the same drive train as the Ultra GT/LX and Ultra MBX off-road buggies use (minus the center diff and one brake disc); it should prove to be a bulletproof on-road drive train.

Suspension. The Ultra GTP features a fully adjustable, double-wishbone front suspension. To allow easy camber and front-track width adjustments, large-diameter pillow balls are used to attach the front knuckle arms to the upper and lower suspension arms. The upper wishbones pivot on largediameter hinge pins and can be moved forward or backward to increase or decrease front caster. The included clip-on spacers allow you to make accurate adjustments.

For additional tuning, the upper arm mounts have two mounting positions, and setscrews threaded into the front and rear suspension arms allow down-travel to be adjusted. A low-profile aluminum front shock tower and short, aluminum-- body on-road shocks with rubber dust boots provide the proper on-road suspension geometry. An adjustable front swaybar allows front body roll to be altered to suit conditions.

In the rear, you'll find extra-long H-arms and adjustable upper links. Extra-beefy tie rods allow camber to be adjusted, and the blue-anodized aluminum rear shock tower has several upper shock-- mounting and inner camber-link-mounting locations for extra tuning capability. A thick, adjustable rear swaybar allows rear body roll to be altered, and the rear suspension-arm mounts feature toe-in cams that can be set for 1 or 1.5 degrees.

Engine and accessories. The Ultra GTP comes with the OFNA/Force .21 engine installed. It features ABC construction, a slide carb, a blue-- anodized-aluminum cooling head and a handy pull-start mechanism. A lightweight aluminum flywheel, 3-shoe racing clutch and a ball-bearing-supported 14-tooth steel clutch bell are installed on the engine. The Ultra GTP also includes a header, a tuned pipe and a large air filter, all of which are securely mounted. As a bonus, the Ultra GTP includes a Pico glow plug, an igniter and a fuel spout that can be used to convert a standard soda bottle into a fuel bottle.

Body, wheels and tires. Of the RC vehicles I've tested, this is the first to include two complete sets of tires that have been mounted and glued to the wheels. That's right! The car comes with a complete set of treaded street radials mounted on black, S-spoke wheels and a set of slicks mounted on chrome 5-spokes. The tires have foam inserts and have been expertly bonded.

The Ultra GTP comes with your choice of a Viper body or McLaren body in clear, which I used for this "Track Report." OFNA plans to release more bodies for the Ultra GTP chassis in the near future.