Orenda OE600

From Wikipedia, the free encyclopedia

The Orenda OE600 is a 600 hp-class 8-cylinder V-block aircraft engine intended to re-introduce piston power to aircraft normally powered by the famous Pratt & Whitney Canada PT6 turboprop. The piston engine offers much better fuel economy and altitude performance, which Orenda Aerospace felt would be attractive for older aircraft who's engines were reaching the end of their lifespan. However, changes in Orenda's business in the post-9/11 time frame led to the project being canceled.

The engine traces its history to the "Generation 2" Chevrolet Big-Block engines of the 1960s. In 1969, General Motors adapted the engine to use a new aluminum block and pistons rather than cast iron, creating the ZL1. Originally, only 50 examples were produced in 1969 so they could be homologated for the CanAm Camaro, additional copies were produced to equip high-end versions of the Corvette, bringing the total production to 71.

In the 1970s, Lee Muir, a race driver, started adapting the ZL1 for aviation use. For better altitude performance, a turbocharger was added, driven, along with a large accessories section, by a gear chain at the front of the engine. The result, known as the Thunder Engine, was shown around the general aviation market during the 1980s. However, financial difficulties led to the project being abandoned after a reported investment of some $5 to $10 million. The original engine, designed for short-duration sprints, proved to be difficult to adapt to the long-running high-reliability aviation needs.

Orenda took over development of the engine in 1994. According to their engineers, the engine as it was simply wasn't capable of running at cruise power for extended periods, and required a huge amount of additional development. They completed the certification process in March 1998 as the OE600A. The OE600's "natural" target was the PT6, the most popular turboprop engine of all time. Although a turboprop has a superb power-to-weight ratio, it is also very "thirsty" for fuel, and its performance drops off linearly with altitude. The OE600 offered better gas mileage, as well as considerably improved climb rates (even though it was heavier) and cruise speeds, all suggesting a lower overall cost of operation. On the downside, any piston engine is much more complex than a turbine, so the OE600 initially had a time between overhauls of only 1500 hours, compared to about 10,000 for the PT6. Orenda expected to increase this to 2500 hours by collecting in-service reliability information, but this still represented a major difference in maintenance vs. operational costs.

Orenda and a number of third parties also started the process of developing modification certifications for various popular aircraft. It was tested as a potential replacement engine on a number of aircraft, including the Air Tractor 300 and 400 Series, de Havilland Canada DHC-2 Beaver and DHC-3 Otter, the Beechcraft C90 King Air, Aero Commander, and Explorer 500R. Basically any widely used aircraft with an engine around 600 hp was considered as a potential target, which Orenda calculated at about 30,000 flying examples with the PT6, Pratt & Whitney R-1340, Wright R-1820, and various Eastern Bloc engines of similar power. Several new aircraft were designed around the engine as well, including the TAI ZIU, Hongdu N-5 and LZ-400 Rhino.

Orenda opened a new service depot known as Orenda Recip at the former CFS Debert in Debert, Nova Scotia. Here they intended to install and service the OE600. At the time they offered a supplemental type certificate conversion for the Otter, planning to follow this with the King Air. They were also interested in smaller and larger versions of the engine, floating a trial balloon at a 750 hp size (the OE750) before deciding on a naturally aspirated 500 hp version instead.

Unfortunately the events of 9/11 required Orenda to re-focus entirely on their military projects (or so they claimed), and the OE600 project was canceled. The design was later purchased by a group of investors who intend to sell the engine under the Texas Recip brand, but it is unclear if this project is continuing. On August 29, 2006 the president of Texas Recip, Paul Thorpe was sentenced to 3 years and five months for defrauding investors, telling them the money was being invested in the engine project, or other investments, when it was actually being used to pay off investors in a previous scheme.

More recently the project has been picked up by TRACE Engines of Midland, Texas. Their web site shows the original OE600, complete with the Orenda name on the headers. Yorkton Aircraft is handling Canadian installations in agricultural aircraft.