BUILDING A QUAD-ROTOR ROTARY IS QUITE AN UNDERTAKING, BUT A 12-ROTOR IS TYPICAL ROB DAHM MADNESS!
Rotary engines, also known as Wankel engines after their inventor Felix Wankel, are a unique type of internal combustion engine that differ significantly from traditional piston engines - pistonless power. Instead of pistons moving up and down within cylinders, rotary engines utilize a triangular rotor that orbits within an epitrochoidal chamber on an eccentric shaft (a version of a crankshaft). This design allows for a compact and lightweight engine with fewer moving parts, resulting in a high power-to-weight ratio and smooth operation. There are some interesting features of a rotary motor, including a compact design thanks to the absence of reciprocating parts, enabling a more compact engine layout. A 13B rotary sort of looks like an extension of the bell housing, it's so compact that when I took out a streetlight with my Mk2 Ford Escort that was fitted with a 13B turbo, I hit on the right side headlight and it wrecked the car, but the motor was still fine because of the way it doesn’t take up space. Rotaries also have a high power-to-weight ratio, and their strange configuration means they have a small capacity when measured like a piston setup. A 13B is rated at just 1.3 litres - as per the name - but with the right bits and pieces, it can make many hundreds of horses. We don’t see new setups these days because while they’re compact and can make great power, they’re inefficient when it comes to emissions and that explains the lack of advancement on them. A new version is pegged to be released sometime soon, but it will be a smaller supplemental motor to an EV setup.
While the most common setup is a twin-rotor 13B, there was also a 20B which was a 2.0 litre that used three rotors, and a 26B that used four rotors - made famous in the Mazda 787B racecar. While original 26B engines aren’t really available, thanks to the way they work, the eccentric shaft can be extended and more rotors added on, so there are loads of aftermarket builds out there as a result. It’s not easy, they rev high and the shaft work and balancing need to be exact. There are very few people who even attempt 6-rotor setups, you’ll find a few in rotary-mad Puerto Rico as well as in Australia, but one was built in SA a few years back, and it was an engineering masterpiece. Arthur from AJ Racing was the brains behind it, and it was fitted to a BMW M6 body to make an epic car that did the whole viral thing online when it was released. In capacity, it’s rated as a 3.0 litre. But now famed rotorholic, Rob Dahm, is having a go at making history. Already well known for his 1,400 hp twin-turbocharged quad-rotor that raced Ken Block’s Hoonicorn, he decided to cement himself in the annuls of rotor tuning. His latest engineering masterpiece is also a custom piece, but it’s a massive twin-turbocharged 12-rotor - TWELVE! Someone already created a 15.7 litre 12-rotor for a boat, but this is the biggest for an automotive application, plus, it’s boosted which means a whole different headache in the setup and development. After much trial and error, the 12-rotor was recently fired up - have a look at the video to see what issues there are and have been. Very interesting, even if you’re not a rotary fanatic.
Take a look at the YouTube video from the biggest rotary fanatic on the planet, Rob Dahm, as he fires up his latest technological marvel, a rotary motor that uses 12 rotors - and a pair of turbos. The planning that went into this build is epic, it's a good idea to watch the other videos leading up to this epic moment: THE 12 ROTOR ROARS TO LIFE! FIRST START | Rob Dahm
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