Drag racers say there is no replacement for displacement. However, when you are going for 400 mph, Mike Akatiff, owner and designer of the fastest streamliner motorcycle in history, would beg to differ. The secret to success is not more cubic inches, but less drag, according to Akatiff. With the aerodynamics dialed in, the TOP 1 ACK ATTACK is headed to the world’s highest salt flat, Bolivia’s Salar de Uyuni, for the Top of the World Landspeed Challenge on August 3-8, 2017 with an impressive goal of exceeding 400 mph.
“The aerodynamics of the ACK ATTACK, or any high-speed land vehicle, are so important,” notes Akatiff. “We’ve run high-speed computer simulations, but to get really accurate data, we performed wind tunnel testing.” Akatiff and the ACK ATTACK team went to the Darko Technologies wind tunnel to unlock the data they needed to go 400 mph on the Bolivian salt flats.
“We wanted to see how the air flows around the bike and found that the bike was already very streamlined the way it is,” says Akatiff. The sleek carbon fiber-skinned streamliner slices through the air with a very efficient drag coefficient of 0.71. That said, Akatiff and the team knew that any reduction in drag would improve their speed. “For every percentage point we further reduce drag, it gives us another 4 mph of speed,” says Akatiff. “So, if we reduce drag by 10 percent, theoretically we will go 40 mph faster with the power we already have.”
Up- and downforces were another critical aspect of wind tunnel testing to ensure the ACK ATTACK doesn’t lift off the ground. Akatiff and his team combine scientific data and wind tunnel testing with years of experience challenging — and beating — the land speed record to come up with solutions. “We added a 30-gallon water tank in the nosecone to create the ‘lawn dart’ effect,” he says. “It adds enough weight on the front wheel to keep the motorcycle balanced and tracking straight.”
The Salar de Uyuni salt flat is nearly 12,000 feet above sea level. However, the team is confident that the twin 1300cc Suzuki Hayabusa engines will deliver more than enough horsepower. A ram air induction scoop channels air into a specially built Garret turbocharger/intercooler system to force-feed both engines with 35 lbs. of boost to generate 900+ horsepower.
Power is not the problem according to Akatiff, keeping his focus on aerodynamics. “We have never been able to run the ACK ATTACK with the doors at the back, for various reasons, but we wanted to find out what reduction in drag they would give us. So we tested the exact configuration we had when we set the land speed record in 2010 — except we put the doors back on to see if we could reduce drag.”
The results were startling: with the doors in place, the wind tunnel tests demonstrated a 40-pound reduction in drag — good for an extra 40 horsepower. This number will be even better in the high elevation of Bolivia.
“If you went 400 mph at the Bonneville salt flats and then go clear up to 12,000 feet with the same amount of drag on the vehicle, you would go 8% or 32 mph faster,” explains Akatiff. “With the doors on we saw another 9% in reduced drag, so that’s going to add another 60 mph with the same power.”
There is one more secret to going 400 mph for the ACK ATTACK. TOP1 Evolution ACK ATTACK Special Formula lubricants. “When we set the land speed record of 376.4 mph, we couldn’t shift into high gear,” says Akatiff. “The TOP 1 lubricants endured incredible abuse, extended high heat and shear forces well beyond what we had anticipated, yet the ACK ATTACK didn’t suffer any scoring, galling or internal engine damage.”
The TOP 1 ACK ATTACK is the only streamliner motorcycle to have made more than 25 runs over 300 mph and without catastrophic engine failure.
See more of the TOP 1 ACK ATTACK in preparation for the Top of the World Landspeed Challenge at Salar de Uyuni:
Article courtesy Speedville.
