The really clever engineering is required to maintain stability. To make sure the torque generated by the turbine does not overturn the car, one of the axles is longer than the other one, balancing the force. In addition Cavallaro put some safeguards in place to make sure only direct wind-power was being used.
“We put ratchets in the system to ensure that we can’t make use of stored energy. I can’t spool the prop up, and then go race with that stored energy,” he says.
Cavallaro first took on his detractors outside of the bulletin boards using this setup in 2010. At New Jerusalem airport in California he travelled downwind at a speed of 2.86 times greater than the wind, proving his concept worked.
But not content with this feat, Cavallaro has also recently shown that Blackbird can also run against the wind. To do this, he reverses the whole set-up.
“All I did to convert it is remove the propeller and replace the blades with turbine blades” he explains. “A turbine blade is turned by the wind, whereas a propeller is just the opposite.”
When the wind turns the turbine it cranks the chain, which in turn moves the wheels. Release the brake and the car begins to pick up speed. The only other difference to the downwind set-up is that the asymmetrical axle is flipped the other way around top provide the right stability.
The most recent tests were done in June this year, when Cavallaro and his team once again descended on New Jerusalem airport. There, they drove the machine into an oncoming wind at a speed two times faster than the windspeed, setting a new record. The North American Land Sailing Association, who confirmed the records, also clocked the craft moving at 22.9 mph (36km/h).
The demonstrations have not silenced everyone, but he seen many people finally accept his idea. One of those includes Richard Jenkins, the designer of Greenbird, a wind-powered vehicle that broke the land speed record for the fastest wind-powered vehicle in 2009. Unlike, Cavallaro’s vehicle, Greenbird works more like an ordinary sailing boat, running at an angle across the wind to outpace it.
Initially a skeptic, Jenkins was swayed after going to see Blackbird in action. “It works. It starts from rest, trundles to true wind speed, then powers to a multiple of about three times the true wind speed,” he wrote.
“To all fellow skeptics, start baking that humble pie, or eat your hat. Your choice.”