Different, yes, but they work
TIM KERN, EAA 825075
VOLKSWAGEN’S FOUR-CYLINDER ENGINE WAS conceived more than 70
years ago, when aviation technology was far ahead of automotive, so it was
no surprise when Dr. Ferdinand Porsche drew from aviation practice as he set
out to design the “people’s car.” The opposed, air-cooled engine was cheap to
produce, reliable, and simple to maintain. It still is, and that is a big reason
for its popularity in so many aircraft designs.
VW-based engines, both amateur- and pro-built, have powered perhaps a
hundred different experimental designs: machines as different as the low-wing Sonerai (which has gone 186-plus mph with a 1600-cc engine in the
hands of racer Brian Dempsey) and the Baby Lakes, an aerobatic biplane. It is
the engine of choice for the modern Sonex and Waiex, for motorgliders, and
for popular plans-built airplanes like the Corby Starlet and Bert Sisler’s
Cygnet; it also has flown in the Bowers Fly Baby. Many of Chris Heintz’s
Zenair machines were designed with a VW as the primary or optional power.
Add Fisher’s Dakota Hawk, the Volksplane, KR- 1 and - 2, Dragonfly, Bob
Counts’ Preceptor Ultra Pup, the Pober Pixie, the Pazmany PL- 4, Avid Flyers,
Kitfoxes, the “Mosler-Max,” and designs from Jodel and Kolb and you start to
get the picture. Powered parachutes (PPCs) and gyroplanes and many other
airframes can also be adapted to VW power. Even certified designs have flown
with VW power—I was personally involved in a (not-too-successful, as it
turned out) Luscombe conversion. VW power has also morphed into essentially new, proprietary designs, as seen in Rotor Way helicopters.
AeroVee 2. 1 Engine
SO, WHY THE CONTINUING POPULARIT Y?
The VW engine is perhaps not “the best” at anything. It does not deliver the best power-to-weight
in its horsepower class; it is not the most economical to run, per horsepower delivered; it may not
even have the longest theoretical life. What it
offers, though, is significant, and its evolution,
through decades of experimentation in aviation
and development in automobiles, has resulted in
making it a strong contender for a flier’s engine.
VW power ratings (roughly 60-85 hp) are a
perfect match to a large number of aircraft. A
thoroughly modern, reliable, and adequately powerful VW engine is within everyone’s financial
reach. The automotive aftermarket continues to
supply rebuild parts (valves, bearings), and the
efforts of dedicated aviation engine-builders have
resulted in options to suit everyone’s version of
what the “ideal” configuration should be. Basic VW
engine technology is well-understood (but admittedly widely debated), unlike some of the popular
small, off-the-shelf aero engines from dedicated