Pneumatic motor low engine temperatures. The Pneumatic Quasiturbine engine is a compressed air pistonless rotary engine using a rhomboidal-shaped rotor whose sides are hinged at the vertices. The Quasiturbine has demonstrated as a pneumatic engine using stored compressed air It can also take advantage of the energy amplification possible from using available external heat, such as solar energy. The Quasiturbine rotates from pressure as low as 0.1 atm (1.47psi). Since the Quasiturbine is a pure expansion engine, while the Wankel and most other rotary engines are not, it is well-suited as a compressed fluid engine, air engine or air motor. Armando Regusci's
Potential energy distance at which "U" becomes zero: formula_34 and formula_35. The choice of formula_36 at infinity may seem peculiar, and the consequence that gravitational energy is always negative may seem counterintuitive, but this choice allows gravitational potential energy values to be finite, albeit negative. The singularity at formula_34 in the formula for gravitational potential energy means that the only other apparently reasonable alternative choice of convention, with formula_36 for formula_34, would result in potential energy being positive, but infinitely large for all nonzero values of "r", and would make calculations involving sums or differences of potential energies beyond what is possible