Researchers at the SMS Institute of Technology in Lucknow, India have come up with the concept for a motorcycle engine powered by compressed air.
The researchers took a conventional air turbine design and studied how different vane angles influenced the amount of power they could get at a given pressure. The air turbine they have in mind puts out 4 to 5.5 kW at 4 to 6 bars of pressure turning a shaft at around 2,000 to 2,500 rpm. This is enough, they say, to power a motorbike.
They found out total shaft work hit a maximum with a 36-deg. vane angle if injection stays at 60-deg. A 45-deg vane angle works better if the injection angle is 45 deg.
One problem with their scheme, they admit, is that the air tank to go any practical distance can get large. Existing tanks would require someone to stop about every 30 km (19 mi) to swap tanks. They figure that's about 40 min of use per tank.
Their paper, "Study of the influence of vane angle on shaft output of a multivane air turbine" by Bharat Raj Singh and Onkar Singh was published May 6, 2010 in the Journal of Renewable and Sustainable Energy.