Last month, Louis Basenese discussed how researchers at Boston University are studying the flight patterns of bats to help create unmanned aerial vehicles that can fly together in a swarm while avoiding collisions.
He also explained how AeroVironment (Nasdaq: AVAV) developed an unmanned aircraft modeled after a hummingbird.
Well, some scientists in Germany are also developing new flight technology based on nature in order to improve helicopters. But their inspiration came from a much more unlikely source: the humpback whale. Seriously.
Limitations of Today’s Helicopter
Simply put, while a helicopter’s hovering – and there’s zero wind – its rotor blades are completely in balance. That’s because both the forward (advancing) and backward (retreating) blades are moving at the same speed, with the same amount of resistance.
When a helicopter moves forward, however, its advancing blade – which moves into the wind – meets more resistance, while the retreating blade moves with the wind. And this imbalance can impact controllability of the aircraft.
Granted, helicopters are equipped to compensate for this imbalance. But there’s a limit. And if the aircraft moves forward too quickly, the blades can eventually stall.
Which, according to Kai Richter from the DLR Institute of Aerodynamics and Flow Technology in Germany, “is one of the most serious problems in helicopter aerodynamics – and one of the most complex.”
Therefore, helicopters are limited in both speed and maneuverability. That’s not exactly ideal, considering that they’re often used by the military and in emergency medical situations, where speed is definitely of utmost importance.
Luckily, Richter and other scientists at the DLR Institute have found a potential solution by researching, yes, the humpback whale.
From Whales to… LEVoGs?
Humpback whales – which can reach lengths of 50 feet and weigh up to 30 tons – might be big. But they’re capable of maneuvering their giant bodies extremely well and can reach speeds of 16.5 miles per hour.
According to the DLR Institute, this “is due to their unusually large pectoral fins, which have characteristic bumps along the front edge.”
Since these bumps essentially keep whales from sinking under high speeds, the scientists thought they could replicate the effect with helicopter blades. Because “flow phenomena in water are similar to those in air, they just need to be scaled accordingly,” as researcher Holger Mai puts it.
They used rubber to reproduce the bumps on the humpback whale fin, placing 186 of the fabricated bumps along the front edge of all four helicopter blades.
And so far, so good.
During testing, Richter says:
“The pilots have already noticed a difference in the behavior of the rotor blades… [And] the next step is a flight using special measuring equipment to accurately record the effects.”
Stalling isn’t prevented completely, however. As Mai says, “Research has shown that these bumps cause stalling to occur significantly later.” Meaning the technology essentially buys time for the pilot to make the necessary adjustments before an actual stall occurs.
So it’s certainly a start.
The best part is, since these rubber bumps can simply be added to the rotor blades, there’s no need to fully replace existing equipment. So once researchers prove that the bumps can maintain lift for fast-moving helicopters, there’s no reason we wouldn’t see it in action soon. And eventually, contours can just be added to rotor blades during the manufacturing process.
They’ve patented the bumps, too, officially calling them Leading-Edge Vortex Generators (LEVoGs). That’s a pretty fancy name for what essentially amounts to expensive pencil erasers.
But as long as they get the job done, you can bet that aircraft manufacturers won’t care what they’re called.