Porsche PFM 3200

Porsche's PFM 3200 was a six-cylinder horizontally-opposed air-cooled aircraft engine developed from their air-cooled line of automobile engines from the famous Porsche 911 sports car. The PFM designation was derived from the name of the division that designed the engines, "Porsche-Flugmotoren" (~ Porsche Flight Engines).

Design and development

In the 1950s, European light aircraft builders began adapting the air-cooled automobile engines from Porsche and Volkswagen into aircraft engines with a series of limited modifications. Porsche cooperated with some of these builders and produced a series of factory-built engines for about six years between 1957 and 1963, the Porsche 678 series. These relatively small engines displaced about 1.6 litres (97 cubic inches) and produced between 55 and 70 horsepower, depending on the version.

Porsche decided to re-enter the aviation market with much larger engines derived from the Porsche 911, starting development in 1981. [ [http://www.porscheengineering.com/peg/en/about/history/about-milestones/81/ "Porsche Milestones: 1976 to today"] , Porsche] As the engines ran at higher speed than most aircraft engine designs, the propeller drive used a 0.442:1 reduction gearing so it could drive common propellers. The high operating speed meant the engine ran more smoothly than older designs, and the use of a muffler meant it was quieter as well. With about 3.2 litres (195 cubic inches) displacement, the normally-aspirated N-series models produced about 210 hp, while the turbocharged T-series produced about 240 hp. This was roughly twice the horsepower of a conventional lower-rpm design of the same size. With single-lever operation, fully aerobatic fuel and oil supplies, direct fuel injection with automatic altitude compensation and optional turbocharging, the PFM 3200 series were some of the most advanced engines on the market.

After being introduced in late 1985 and starting to generate increasing interest in the general aviation (GA) market, Porsche exited the field during the massive downturn in the market in the late 1980s, closing the lines in 1991. It is suggested that the program cost them US$75 million to develop and produce the small number of engines delivered (about 80). [ [http://home.comcast.net/~aeroengine/Porsche.html "Porsche Factory Aircraft Engines"] ] Although marketed for only a short period, the PFM was found on a variety of aircraft as the primary powerplant, or as one-off modifications. These included the Extra 330, Mooney M20L, Socata TB-16, Robin DR400, Ruschmeyer MF-85 and others. Only the M20L went into production, with 40 produced in 1988, and one more in 1989.

Under United States law, where most of the engines were used, Porsche was required to continue to supply parts and maintenance for the engines. Instead, they claimed to have destroyed all spare parts and refuse to support the very engines they put into the marketplace. The company has even gone so far as to try and render the planes worthless by claiming the engines need certain parts replaced after a number of flight hours and then refusing to provide technical information so such parts could be privately manufactured.

Versions

* N00: de-rated for automotive fuel
* N01: 212 hp at 5300 rpm
* N03: type-certified N01 for the Mooney M20L, 217 hp at 5300 rpm
* T03: similar to the N03 but with a Garrett turbocharger, 241 hp at 5300 rpm, critical altitude 18,000 ft

References

See also

*Chevrolet Corvair engine-another "flat-six" auto engine also converted for use in general aviation

Further reading

* Helmuth Bott, Heinz Dorsch, [http://www.sae.org/technical/papers/850895 "Porsche Aircraft Engine P F M 3200"] , SAE International, April 1985, #850895
* Alfred Scott, [http://www.seqair.com/Other/PFM/PorschePFM.html "Dead on Arrival: Porsche PFM"] , "Falco Builder Letter", March 1988