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Light Sport Aircraft - New Power - Across the Desk - LIGHT AIRCRAFT ENGINES

August 2007

Category: GA Buyer Europe Magazine

Author: Light Aircraft News


ACROSS THE DESK - An occasional look
at what’s new in light aircraft engines

New Power for Light Sport Aircraft

In a continuation of our regular review of light aircraft engines GA Buyer Europe, has been looking this month at a new engine produced by Power Plant Developments Limited (PPD), a venture formed by the alliance of two of the most experienced companies in the UK.

The design of the engine was carried out by the internationally renowned design consultancy Weslake Air Services, Ltd. under a commission from aviation engine repair and overhaul company, Jade Air plc. The engine seen in a brief preview at Aero Expo is a three cylinder, opposed piston, two-stroke diesel engine that has been specially created for the Light Sport Aircraft (LSA) market.

The engine has been branded the “Gemini” engine because of its twin crankshaft, two pistons per cylinder design. While the Gemini engine ushers in a new-generation of power plant, it is based on a proven design. The concept of opposed piston, two stroke diesel engines has been around since 1932 when Junkers introduced it for their six cylinder, 12 piston, 867 horsepower Jumo 205 diesel engine.

The principal operation is that the combustion chamber is formed between two opposing pistons occupying the same cylinder. Inlet and exhaust ports are formed by orifices in the cylinder walls, opened and closed by the movement of the pistons in the cylinder. Induction and scavenging is achieved by positive pressure from an engine driven supercharger. (See schematic)

The Gemini engine’s twin half-length crankshafts are shorter than conventional crankshafts and therefore have a greater torsional stiffness. The basic layout of this opposed piston engine also allows for significant weight and costs savings over its competitive counterparts by eliminating the camshaft, valve gear and cylinder head joints found in other opposed aircraft engines.

The first-generation, three cylinder, Gemini engine delivers 100 horsepower yet weighs only 70.5 kg (155.43 lbs) giving it an extremely high “Power to Weight” ratio. The Gemini not only holds its own with aviation gasoline engines, but it is far superior in performance, economy and weight saving to what is currently available in other diesel aircraft engines.

Dimensionally too, the Gemini engine is well ahead of the opposition, being up to 30% smaller than the ubiquitous Rotax gasoline engine which until now has powered the vast majority of LSA designs. This, together with reductions in operating costs within Europe of up to 63%, is bound to get the attention of LSA OEMs and GA Buyer Europe will be closely following progress as development and production of the engine continues.

PPD is also planning higher power variants of the Gemini engine in which a turbo charger will be used to increase power and offload the supercharger drive to the further benefit of both power and fuel efficiency. According to PPD design studies have been completed for Gemini engines of up to 600 horsepower.

Aviation industry veteran, Timothy T. Archer, formerly CWEO of Superior Air Parts and long time TCM executive, has been appointed as President and CEO to help guide the company’s efforts in manufacturing this revolutionary new diesel piston engine and bringing it to market in 2008.

According to Archer, “These cost-effective power plant solutions for light sport aircraft will initially be built in the UK using the established facilities of Weslake and Jade Air. We plan a new production facility to be brought online in 2011, (possibly in the US) to meet the demands of an increasing product range.”

O More information contact: info@jadeair.co.uk


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