New-wave engine

DN Staff

April 3, 2000

15 Min Read
New-wave engine

West-coast inventor Bob Montgomery first learned the way of the waves in the 1960s riding Southern California beachbreaks as a teenaged protege of surfing legend Duke Kahanamoku. Like many other surfers, Montgomery imagined a dream machine-a one-man hydrokinetic rocketship that would combine the freedom of surfing with a water ski's ease-of-use and maneuverability. "I wanted to ride a high-performance, motorized surfboard," recalls the 50-year-old ex-pro surfer.

Now, due to his own determination and the availability of the latest materials and CAD tools, he is about to see his dream come true. It has taken the form of the Igniter 2000 TM model Powerskitm Jetboard TM , a new product from Powerski International, Inc. (PSI), a company he founded in the garage of his San Clemente, CA home. Montgomery is currently building a hundred prototypes for testing this summer, and production models should go on sale later this year.

He says he has three U.S. and 27 foreign patents, with 61 more pending worldwide, for this water craft that allows the rider to stand rather than sit, as is the case with most competitive products-and it's making quite a splash in the popular press. For example, the Igniter 2000 and its proprietary engine won the Popular Mechanics Design and Engineering Award for the new Millennium. It's also been featured in magazines such as Popular Science, Watercraft World, and Boating World. Among the Igniter 2000's engineering innovations:

A proprietary two-stroke, water-cooled engine that puts out between 30 and 50 hp, depending on displacement. The 6.5-inch thick, 50-cc engine weighs about 40 lbs, but use of a metal matrix composite material should drop the weight to about 28 lbs, Montgomery says.

An axial-flow jet pump that delivers 350 lbs of thrust through a proprietary gear-reduction transmission. The gear reduction, built into the bottom end of the engine, is new to the power watercraft industry. It enables engineers to match the engine's optimum rpm to that of the jet pump to enhance the craft's performance.

A design that puts the center of gravity under the rider's feet, rather than behind or in front of the rider as is the case with similar sports water craft.

Dual "hydrosteps" on the bottom of the hull that put the pivot point directly under the rider's feet, enabling high-speed planing and turning. They lift the craft partly out of the water as it skims along, and direct the line of water rushing past the rails during top-speed turns, stabilizing the craft.

A four-ft-long "armpole" consisting of steel cable and a sleeved wire harness covered by injection-molded rubber. The rider holds the grip on the end of the armpole that has start and stop buttons, left and right thumb throttles, speedometer and fuel gauges, and a safety kill switch.

A vaporless fuel system that improves environmental safety and prevents the loss of fuel through evaporation, prevents contamination, and maintains fuel integrity.

Design of the Igniter 2000, which has been a ten-year project, required overcoming several engineering challenges. Dealing with five significant natural forces: weight, buoyancy, hydrodynamic lift and drag, and thrust, Montgomery combined a high thrust-to-weight ratio with a hull/rail design and center of gravity placement that stabilizes the craft at all speeds. The design also enables high-speed planing and high-thrust G-force turns with simple shifts in weight of a rear-mounted rider.

But the real key was packaging the jet drive system inside the hull under the rider's feet. AutoCAD, from Autodesk (San Raphael, CA) and Pro/ENGINEER from Parametric Technology Corp. (Waltham, MA) were critical tools in the design process.

Key to the low-profile engine was laying the cylinder down with respect to the crankcase and moving the intake and exhaust ports to opposite sides, which required rotating the piston 90 degrees.

Sitdown & heavy. As a pioneer in the industry, Montgomery saw changes in the personal watercraft (PWC) design. As a standup watercraft, he says, the typical Jet Ski had proved relatively unstable-riders found it difficult to maintain a standing position because of the craft's forward center of gravity. Kawasaki's solution to the problem was to go from "standup" to "sitdown." The Jet Ski became a heavy, sitdown, square-railed directional jet-drive watercraft. The move by Kawasaki and other major industry manufacturers toward a heavy sitdown craft built up Montgomery's confidence in his plan for a much more hydrodynamic, standup watercraft. Where they went sitdown, he would go standup. Where they went heavy, he would go light.

"They lost the personal'from the personal water craft when they went sitdown," he asserts. "The new machines were heavy, bulky, almost boats." So, Montgomery left the Jet Ski industry and set out to help pioneer the "jetboard" industry.

The first actual jetboard/motorized surfboard appeared in the 1960s. The "Bloomingdale Jetboard," a handle-less standup craft designed by Renard Storey, featured a low-powered (3-5 hp), 10-lb, 80cc engine capable of moving the craft at a speed of no more than 3-5 mph. Storey had designed his jetboard for surfers so they could eliminate paddling, according to Montgomery, who had heard about the original jetboard for years before finally getting a look at one in the early 1980s. When finally he saw the Bloomingdale board, he says, he knew why surfers

hadn't taken to the low-powered craft.

"It was built with a putt-putt' mentality," he recalls. "No thrust, so no turns." For Montgomery, the limitations of the Bloomingdale board only confirmed for him the efficacy of his own design, which had taken shape years before he finally saw Storey's design. In the years before ever assembling material for building his first jetboard prototype, he mentally "pre-engineered" his version of the standup PWC: a high-performance "power ski" board long, narrow, buoyant, lightweight, low-profile, and waterproof-propelled by a compact, powerful, jet drive system.

Montgomery continued to refine his ideas, and in 1981, he joined Surf-Jet Corp., Janesville, WI, the one manufacturer that shared his belief in the standup PWC. As new product manager for the company's power-operated standup craft, he designed the production hulls for the Surf-Jet Models 236 and 275, earning a place on the patent records for his efforts. Then, as the company's west coast marketing and sales manager, he began marketing the Surf-Jets. His extensive knowledge of design, engineering and manufacturing helped make the Surf-Jet a force in the PWC market in the 1980s.

But the Surf-Jet, as Montgomery saw while with the company, left plenty of room for the sort of hydrodynamic PWC he was designing and building. The position of the Surf-Jet's large engine-deadweight on the tail-placed the craft's center of gravity behind the rider, which cut down maneuverability. The standup Jet Ski's instability problems had stemmed from the placement of the craft's center of gravity in front of the rider.

Montgomery offered Surf-Jet his ideas for what would eventually become the Powerski Jetboard-with the center of gravity beneath the rider's feet, the rider's weight would dominate the craft to provide complete steering control. But, he says, Surf-Jet wasn't interested, and Montgomery moved on. In 1987, the entrepreneur in Montgomery set out to meet the challenge of pulling off a major marketing success without the benefit of initially having any money to pay for it. He started in his garage, hand-crafting his dream machine.

In 1990, to formally raise the funds necessary for taking the craft to the working prototype, pre-production stage, he formed the HydroForce Group General Partnership. During the next few years that the jetboard took shape, Montgomery struggled to keep focused on his mission, even working other jobs to pay the bills as he labored in his off hours. All the while he operated a "stealth" research and development campaign, strategically keeping the prototype hidden from the public (and competitors) as he slowly secured patents, trademarks and other intellectual property rights protections.

His work was not without conflicts, however. On one occasion he had to resort to fisticuffs to thwart a group of would-be thieves intent on stealing his design. Once the Powerski Jetboard was fully protected, Montgomery revealed his prototype to the world, securing product placement stories for the craft in national magazines. A card-carrying member of the Screen Actors Guild, he has also acted in and performed stunts for numerous TV productions and in two Hollywood motion pictures, including Kevin Costner's 1994 flick "Waterworld."

In 1995, Montgomery co-founded PSI and moved to production facilities in Brea, CA, where he finished design of the Igniter 2000.

Designing the dream. The most significant challenge facing Montgomery in bringing his jetboard idea into reality was the engine. "I needed an engine with the horsepower-to-weight ratio that would give the consumer the ultimate jetboarding experience," he says. After an extensive worldwide search failed to turn up a suitable prototype, he says, he decided to build his own. Hiring Bjorn Elvin as PSI's engine project manager, Montgomery put Elvin's small-engine experience-gained while working at Husqvarna's motorcycle and chainsaw division-to work. Key to the low-profile engine was laying the cylinder down with respect to the crankcase and moving the intake and exhaust ports to opposite sides, which required rotating the piston 90deg.

Montgomery and Elvin developed the first engine, designing it using AutoCAD and Mastercam. With AutoCAD, they produced detailed 3-D drawings of the engine to be used by the machinist for manufacturing. Mastercam translated the input information into the appropriate machine language for the mill. Mastercam's toolpath verification feature enabled the team to generate a solid model of the finished part, complete with every scallop, chamfer and radius.

While the current Igniter 2000 is powered by a two-stroke aluminum engine, PSI also has prototyped a 320 cc version of the two-stroke that puts out 50-55 hp. According to Elvin, engine displacements up to 600 cc are possible with this design. "We probably are going hit the market with a 320 cc engine," says Montgomery, "because our goal is at least 45 hp on our first entry."

"Production models will start with fuel-injected two-stroke engines, but PSI is working on an environmentally friendly four-stroke engine, so that the Igniter 2000 can be "as green as possible," says Montgomery. Four-stroke engines emit 97% less pollution than conventional two-strokes, use half as much gas, and keep all oil inside instead of discharging it into the water and air. Also, the low-end torque of a four-stroke provides an ideal powerband for driving through leaning turns, he adds.

Montgomery partnered with Wayne Morris and Tibor Nagy of Source One (Brea, CA) to develop the Pro/ENGINEER files and refine the billet engine even further in terms of strength and weight. The first 100 test engines are being produced using sand-cast tooling. Then Source One will optimize the engine design for die-cast tooling. To improve the engine's hp:weight ratio even further, Montgomery is considering manufacturing the production engines using Irvine, CA-based Alyn Corp.'s Boralyn(TM)metal-matrix composite material, and its precision soluble-core technology. Boralyn is a mixture of aluminum and a boron-carbide ceramic.

According to Robin Carden, founder of Alyn Corp., "Boron-carbide is the third hardest material known to man. Even at high temperature, it's harder than diamond. The Igniter 2000 is a Van Gogh, and we want to be the diamond inside it," he says. GM's EV-1 engine cradle, golf shafts for golf clubs, and satellites are currently produced using Alyn Corp.'s material and processing technology, primarily because the Boralyn material is lighter, stiffer, stronger, and very easy to fabricate, says Carden.

Alyn Corp. claims it can pressure cast one PSI engine every 30 sec, and the soluble-core technology will create passages inside the engine that are as smooth as marble. "We are able to get very smooth intake and exhaust ports on this engine," he adds.

Hefty handle. Standing on and controlling a fast-moving, motorized surfboard through a "G-Force" turn requires a long handle. The design team developed a custom, ergonomically correct, ambidextrous handle unique to the Igniter 2000.

The throttle switches on the handle at the end of the arm pole act as levers that let the rider regulate the supply of vaporized fuel that goes to the engine cylinders. The dual throttle levers are independent halves of the same universal cylinder/cam-type mechanism. The mechanism consists of a rotating/sliding internal centerpiece that imparts motion to a roller moving against its edge. The throttle cam acts as the point of pull on the armpole cable. "It's aggressive," notes Montgomery. "It doesn't take much pressure on the throttle switch to speed up this craft."

To bring the craft's handle to reality, the PSI team used Alias(R)AutoStudio TM computer software, a three-dimensional (3-D) industrial design system. Alias Auto Studio relies on mathematics to describe physical objects, and enabled PSI's design team to create geometric models of the handle with precision surfaces. They then used the 3-D Alias CAD drawing to hand-carve preliminary foam models.

"Coming into this process we had our designers do ergonomic studies so that the handle will fit the 85th percentile of people," says Montgomery. To produce a real-life, tangible plastic replica of the handle, they used 3D Systems SLA-250 series stereolithography equipment. Relying on the Alias drawings, the equipment directed ultraviolet laser radiation onto a vat of polymer resin (liquid plastic) to carve the 3-D model, which was cured in an ultraviolet oven and then hand-polished and finished to specifications.

Dual-hydrostep. The "rocketship look" of the Igniter 2000 comes from its streamlined, hydrodynamic, low-profile composite hull-8-ft-4-inches in length. Throughout the past 20 years, Montgomery has hand-built numerous operational prototypes. In designing and fabricating the Igniter 2000 hull, Montgomery and his team used FARO Technologies FaroArm, a portable laser tracker instrument with multi-axis, articulated arms, along with a CAD-based measurement program. They digitally scanned the hull of a hand-built Igniter 2000 model to create a digital "point cloud" on the computer. Then, Freed Designs did the modeling in Alias.

In the software, the PSI team improved Montgomery's hand-built design by lowering the profile by flattening the space in the hull where the craft's non-directional jet-drive system-engine, pump and propeller-is mounted. Another significant change: The engine is housed in a totally leak-proof, watertight compartment with an inflatable seal that makes the craft a "three-quarters submarine" submersible. Riders can plunge underwater or float on the surface without stalling, explains Montgomery, thanks to a clever one-way valve on the exhaust and dual plurge valves on the intake.

Most popular, steered, sit-down personal water craft have a flat-bottom/square siderail shape. During turns, those with straight side rails can produce abrupt and unexpected moves that make the craft prone to suddenly tipping over. In contrast, says Montgomery, Igniter 2000 carves high-speed planing and turns without trouble.

Vaporless FUEL system

This patented fuel storage system reduces the number-one safety and environmental threat related to fuel storage-vapors. A rigid outer shell contains a flexible double-walled bladder made of a pliable, composite material that is impermeable to fuel. Hydraulic fluid fills the space between the walls, allowing the bladder to expand just enough to hold the amount of fuel received as it enters the empty bladder.

The pliable composite material used for the double-walled bladder is strong, puncture-resistant, flame resistant, and withstands extreme temperatures.

When fuel is consumed and the bladder empties, its volume decreases, continuously contracting, and never allowing air space to form. Without air contacting the fuel, vapors and subsequent vapor hazards are eliminated, even when the tank is empty.

Integrating easily into existing fuel systems, the vaporless fuel system eliminates the need for costly venting and on-board canister systems. It also prevents the loss of fuel through evaporation, prevents contamination, and maintains fuel integrity (including diesel and jet fuels). Moreover, the design may potentially solve a variety of problems in applications ranging from chemical storage to contamination in water storage systems on recreational vehicles.

Kevin Madison, Top Dog Systems, Box 508, Ridgewood, NJ 07451; Tel: (877) 668-2767.

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