conventional wheel on steel, with a corresponding reduction in safe separation between trains. The Shilovsky claimed his designs were actually lighter than the equivalent duo-rail vehicles. The gyro mass, according to Brennan, accounts for 3–5% of the vehicle weight, which is comparable to the bogie weight saved in using a single track design. Turning corners Considering a vehicle negotiating a horizontal curve, the most serious problems arise if the gyro axis is vertical. There is a component of turn rate acting about the gimbal pivot, so that an additional gyroscopic moment is introduced into the roll equation: This displaces the roll from the correct bank angle for the turn, but more seriously, changes the constant term in the characteristic equation to: Evidently, if the turn rate exceeds a critical value: The balancing loop will become unstable. However, an identical gyro spinning in the opposite sense will cancel the roll torque which is causing the instability, and if it is forced to precess in the opposite direction to the first gyro will produce a control torque in the same direction. In 1972, the Canadian Government's Division of Mechanical Engineering rejected a monorail proposal largely on the basis of this problem. Their analysis was correct, but restricted in scope to single vertical axis gyro systems, and not universal. Maximum spin rate Gas turbine engines are designed with peripheral speeds as high as , and have operated reliably on thousands of aircraft over the past 50 years. Hence, an estimate of the gyro mass for a , with cg height at , assuming a peripheral speed of half what is used in jet engine design, is a mere . Brennan's recommendation of 3–5% of the vehicle mass was therefore highly conservative. See also Adhesion railway Bicycle and motorcycle dynamics Gyrocar Segway HT Lit Motors References Bibliography External links Monorail Society Special Feature on Swinney's monorail Gyroscope Railroad Monorails Experimental and prototype gyroscopic vehicles Irish inventions Australian inventions