PATS, The US supplier of auxiliary-power-unit (APU) installation kits, has revealed a lightweight rotary-engine APU for corporate jets which the company claims will lead to significant cost savings compared with conventional turbine APUs.
The "non-turbine heavy-fuel engine" is based on the Wankel engine design originally used in motor cars and motor cycles, but more recently used as a power plant in unmanned air vehicles .
Steve Huter, PATS' head of rotary engine development, says that the unit is ideal for retrofitting to aircraft such as early-model Learjets and Cessna Citations, which rely on external power for engine starting. "The key market is for aircraft which require electrical and hydraulic power, but not bleed air," says Huter.
The Columbia, Maryland-based company is "-in the final stages of endurance testing-certification is scheduled one year from now", says Huter, who adds that the prototype single-rotor unit measures 325 x 325 x 700mm, weighs 55kg, rather than the 230-270kg for an equivalent turbine APU, and supplies 10kW of power, delivered at up to 350A.
A major advantage of the unit, says the company, is that it can be run on a wide variety of fuels -"diesel, kerosene-it really doesn't care", says Huter, who adds that "-that's what the US wants for a 'single-fuelled' military", referring to the fact that the unit has been developed alongside a dual-rotor engine for US Army vehicles .
Running costs are likely to be "a fraction" of those for turbines, at around $5,000 a year as opposed to around $50,000, and fuel consumption is claimed to be "around 10%" that of turbine engines. Purchase price including installation will be $100,000-150,000, according to Huter, while a typical PATS turbine APU installation would be "around $350,000".
Source: Flight International
