Amidst whispers of the iconic Wankel rotary engine revival, what’s remarkable is the manufacturing process. Mazda the vehicle only has a maximum of three propellers. However, one intrepid boatbuilder in the backyard has gone beyond this, leaving us in awe of his incredible creativity.
Tyson Garvin, a record holder rower, built an incredible engine with a displacement of 960 cubic inches, or more than 15.7 liters, and a whopping 376kg (830lbs). Garvin shares that in its naturally aspirated form, the engine has produced an incredible 1400 horsepower. When powered with racing fuel and methanol, it is theoretically only capable of over 5000 hp, although this has yet to be proven.
Curious minds may wonder about the origin and purpose of such an extraordinary motive. Garvin began working on this innovative design in 2010, looking for an alternative to traditional marine performance engines.
The origin of this innovation stems from Garvin’s desire to maximize power output in the space normally occupied by a large marine Chevrolet V8. After measuring the available area, he deduced that 12 propellers would fit in that space. In total, the 12-blade motor has a length of 76cm, a width of 80cm and a height of 61cm.
“We have reached the limit of what a large block can do,” explains Garvin. “Our goal is to generate more continuous power, not just power suitable for drag races. The rotary engine provides more power for its size.”
Garvin recalls the design process: “We tested 100 different ways to arrange the propellers. The ‘Y’ design eventually emerged as the only viable method to accommodate 12 propellers within the confines of a large cubic space.
At its core, the engine consists of three rows, each with four propellers. The top two bands connect via gears at the rear of the engine block to the bottom hub strip, which is linked to the output shaft. One row is configured to rotate in the opposite direction to the main chain, while the other has an idling gear, ensuring it rotates in the same direction as the main shaft.
“We needed a bank that rotated in the opposite direction so that the exhaust side aligns with the other banks,” explains Garvin.
Garvin designed the engine with versatility in mind, making it suitable for recreational sailing with around 1,400 hp with up to 400 hours between scheduled maintenance. Plus, with a pair of 122mm turbines (10 pounds increase), the engine can churn out 2,400 horsepower in about 200 hours—perfect for poker runs and other fun mining activities. These power numbers are based on 87 octane fuel.
By increasing the boost to 25 pounds on racing fuel, power levels can exceed 3,600 horsepower, and with a 50-pound increase, the engine is capable of reaching more than 5,000 horsepower. For steady-state operation, the recommended rpm is between 8,500 and 9,000, while the fully throttled version can reach 14,000 rpm.
During testing, the 12-blade engine produced an impressive 497 hp at just 3,200 rpm—less than a third of the suggested red limit—where Wankel really shined.
Garvin and his team manage all the design and machining work in-house, with only the rotor being shared with the original Mazda 13B 2-rotor.
Observant readers may notice that the 12 propellers of the Mazda 13B will “only” have a capacity of about 7.8L, not 15.6L. However, spinning has a unique advantage, firing more often than a conventional 4-stroke piston engine.
Tyler addresses this in one of his Facebook posts, saying, “The motor is 480 cuin when spinning each propeller once, as counted for one rotation. It’s 960 cuin when counted as one big block with two revolutions of the crank and 1,440 cuin if you shoot each side of the rotor.”
We first learned about this ambitious project a few years ago, but sadly, there have been no updates for about three years. We eagerly await the day Tyler installs this miracle in a boat, allowing us to witness its power in action!
You can follow the development of 12 Rotor This.
