EAA Experimenter 21
the engines are used for a short time each day. PBS also makes
a 240-hp turboprop version of its engine that is fl ying in an RV-
10—interesting. If you have to ask, you can't af ord it. PBS—
www.
PBSVB.com/aircraft-engines
, www.TurbineSolutionGroup.com ;
JetBeetle—
http://JetBeetle.com , http://JetBeetleUSA.com
Here's a bit of Oshkosh lore. The seeds of the small aircraft
diesel engine revolution were planted many years ago by Michael
Zoche and family of Munich, Germany, by displaying its ever-
evolving X-4 and eight-cylinder, air-cooled, two-stroke radials.
The Zoches woke people up to the possibilities of aircraft diesels,
which led to the GAP engine from Continental and indirectly to
the Delta Hawk project.
www.Zoche.de
Delta Hawk is a liquid-cooled V-4, direct-drive, two-stroke
diesel of 180 hp and up. From Wisconsin, it is currently being test
fl own in Cirrus, and STCs are planned. Certifi cation is expected
in 2015.
www.DeltaHawkEngines.com
Engineered Propulsion Systems, also from Wisconsin, has an
engine being fl ight tested in a Cirrus, too. Starting at 350 hp, it is
called a fl at V-8 engine. It is liquid-cooled, geared, turbocharged,
and four-stroke.
www.EPS.aero
Safran SMA makes the very aircraftlike 230-hp, fl at-four, air-
cooled, four-stroke, turbo diesel and is testing a fl at six of 350 to
400 hp.
www.SMAengines.com/?lang=en
Continental, now Chinese owned, is covering its diesel bets
by buying early SMA technology for a four-cylinder, air-cooled
diesel and the Thielert/Centurion line of I-4, V-6, and V-8 cylin-
der, Mercedes-based, liquid-cooled diesels.
FlyEco has "Smart" diesel and gas engine conversions.
www.FlyEco.net
In general, aircraft diesel engines are a bit heavier and more
expensive than the gas engines they are intended to replace
but with much lower fuel consumption of less expensive, more
widely available fuels. Is diesel the future? For homebuilders,
as more diesel cars become available in the United States, the
choice of organ donors for auto engine conversions increases. It
has already been done in Europe with great success.
AUTO ENGINE CONVERSIONS
Engines based on high-volume production auto engines are less
expensive than specially made aircraft engines. Let's look at some
of the less aircraft-like engine conversions.
The Subaru fl at fours and sixes are still popular choices for con-
version, though I did not see any vendors at Oshkosh this past year.
There have been auto engine conversion vendors that have
sold underdeveloped and undertested products. Two or more of
the Subaru developers fall in that category. One of them has moved
on to a Honda Fit conversion. Viking Engines is marketing an
engine based on a Honda Fit engine turned on its side to better fi t
a normal fl at engine cowl.
www.VikingAircraftEngines.com
Raven Rotorcraft & Redrives has a 19-year history of three- and
four-cylinder Suzuki engine conversions and is now developing an
upright Honda Fit engine addition to its line. Raven successfully
converted a four-cylinder Suzuki to a sidewinder, but it does not
think it is a cost-ef ective choice for the Fit engine. Raven uses a
AutoPSRU's inline gearbox was developed to replace a troublesome unit from a
defunct Subaru converter. It would also be useful for Mazda rotary engines and
others that need a co-axle shaft, with non-reversing output.
This tiny, 240-hp turboprop from PBS is being tested in the RV-10 shown behind it.
If you have the money for the engine and fuel, go for it.
The compact and lightweight PBS 240-pound thrust turbojet powers the Sonex
Jet and some self-launching sailplanes. Homebuilt jets are not just for air show
performers now that engines like this are available.