Model: UL-125 Wildfire Hull type: 1/12-scale, 3-point hydro Manufacturer: RC-Hydros.com Hull material: fiberglass or ABS Length: 25 in. Weight: 4.5 lb Power range: .05 to .40 electric Power used: Graupner 700BB Radio req'd: 2-channel Radio used: Futaba 3PD w/FMA* 200 servos Speed control: RC-Hydros.com SC2 Prop used: Octura* 450 Price: $165 (fiberglass hull); $240 (hull and hardware). Comments: the UL-125 is an excellent entry into fast electrics that comes with expert construction guidance and offers solid performance on the water. Hits • Great agility. • Good instructions. • Strong hull. Misses • Fiberglass requires filler and sanding.

For many modelers, hydros represent the benchmark of excitement. Once only the domain of backyard "ply-guy" scratch-builders, these marine missiles have become like the sleek, CAD-drawn corporate icons we see racing today. As full-size hydroplanes have evolved, RC models have taken a ride on their composite coattails and have packaged up the same excitement in scaled-down trim. I was thrilled to get a chance to shake down one of the newer, fast-electric models: the UL-125 from RC-Hydros.com*. One thing was certain: this was an opportunity to see whether advances in battery technology and hotter motors could win over this nitro purist.

The UL-125 is a 1/12-scale boat that's available molded in either ABS plastic or fiberglass. There is no mistaking that the UL-125 was created by a modeler who wants to see you succeed. The illustrated instructions are written from the standpoint of "Here's what works." It's up to you if you want to experiment, but I recommend that you begin with RC-Hydro.com's solid foundation.

The first step in assembly is hull preparation. Once you're satisfied with the boat's appearance, mark the driveline locations that are indicated in the illustrations. Follow these steps carefully because they will have a great impact on the performance and look of the finished product. Next is the motor mount. To make the best use of your shop time, prepare the wings for installation while the motor mount's adhesive cures. The wooden wings will need to be sealed before any finish coats can be applied.

Left: The bare fiberglass hull requires some sanding and filling, but it's well worth the extra effort to make a good-looking, fast boat.
 
The hull bottom must be cut to accommodate the Graupner* driveline components included in the kit. A Dremel* tool with a sharp cutoff wheel works well for this task. Performance is gained in small steps, and one of the easiest ways to achieve it is with a straight drive train. Wisely, it's recommended that you assemble the components before you place them in the boat. When everything has been aligned properly, tack-glue the stuffing box into place with a few drops of CA. Use accelerator to set the adhesive. Use only enough CA to maintain the alignment because you'll want to make the main bond with 5-minute epoxy. If you plan to race the UL-125 or to run a powerful motor, install longitudinal braces along the stuffing box. After you've fit the hardware and radio gear into the hull, attach the wings. It's very important that you install them so that they're aligned straight and are canted outward 5 degrees. Likewise, for the boat to ride correctly at speed, the front canard must be parallel to the water's surface.

Now it's time to put the "show" with the "go." If you haven't already done so, give the hull's exterior a final sanding and priming before the finish coat. My prototype hull was finished with yellow Krylon and the UL-125 vinyl graphics available directly from RC-Hydros.com.

Left: an off-the-shelf motor, battery packs and radio gear add up to a remarkable performer at a reasonable price.

Right: standard Graupner running hardware is used, and an Octura 450 provides thrust.
 
If you'd like to try your hand at fast electrics, this is a hot candidate. The UL-125 is a nice balance of prefabrication and builder involvement that serves up very rewarding results. Using the Graupner setup and stock trim recommendations will result in a rewarding way to join 12-cell competition.

*Addresses are listed alphabetically in the Index of Manufacturers in the magazine