Superior Air Parts And AC Aeronautical Ltd Jointly Developed
XP-408AC Engine Inspired By Formula One Auto Racing
An all-new, 230 horsepower, four-cylinder engine designated
XP-408 Advanced Competition (AC) has been unveiled by
representatives of Superior Air Parts, Inc., and AC Aeronautical
LTD, which jointly developed the powerplant. “Superior has
always led the industry in introducing emerging technologies that
advance the performance, efficiency and reliability of piston
aircraft engines beyond what our competition can offer,”
stated Timothy T. Archer, Group CEO, Superior Air Parts, Inc.
“When I first saw the amazing work that the team from AC was
doing, I knew that it would be ideal to collaborate with them in
creating this new-generation engine.”
XP-408AC
“The XP-408AC has been designed with safety as a priority;
efficiency as a requirement, and performance as a positive
result,” explained Andrew Higgs, Director and Chief architect
of the 408 program, at AC Aeronautical LTD. “To be able to
achieve these high goals you need to start with an engine that is
made to the highest quality standards. That is what we have
available by using Superior’s outstanding XP-360 as the base
engine. Take its proven quality and durability and add our racing
inspired upgrades and you get an engine that delivers 230
horsepower and can do it reliably for a long time.”
Higgs said that the AC Aeronautical engineering team drew on many
years of experience in professional motorsports and competitive
flying. Each of the company’s directors holds a pilot’s
license and their team boasts a World Record Holding pilot (Steve
Noujaim) and a Red Bull Air Racing double world champion, (Paul
Bonhomme). Whether flying for pleasure or prize these are pilots
who demand and rely on excellence when it comes to their
engines.
To advance the state-of-the-art in piston aircraft engine
design, performance and reliability, the AC Aeronautical team took
many cues from the world of Formula One auto racing to develop the
engine’s key components including the new crankshaft,
connecting rods, pistons and piston pins. “Our team use the
latest techniques in finite element analysis to select the most
appropriate material for these new parts,” he said.
“They are designed to the very highest quality standards and
manufactured to exacting tolerances. The results are components
that provide higher performance and higher reliability, while being
overall significantly lighter than the stock parts they
replace.”
Among the numerous advancements introduced for the XP-408AC
are:
- Dynamically balanced crankshaft designed to dampen firing order
vibration and increase the engine stroke to 408 cubic inches.
Reduced vibration minimizes engine component stress and helps
maximize engine reliability and efficiency.
- New four-bolt connecting rods, which better distribute the
clamping loads to help stop bearing distortion.
- New heavily bridged slipper-racing pistons that are
significantly stiffer than standard pistons. The new design is also
42% lighter than stock pistons. Each piston set is matched to
within 0.5 gram.
- A significant weight reduction in the dynamically balanced
crankshaft rotating assembly, resulting in a significant reduction
in inertia with a corresponding reduction in the stress and
vibration that is found in the traditional engine.
The main goal for the designers was to move as much weight from
the reciprocating parts to the rotating parts to ultimately reduce
engine stress and vibration. “During our testing, we found
that even while producing its full 230 horsepower, the XP-408AC
engine actually generates lower peak to peak stress levels than a
similar specification 360 engine at a similar RPM setting,”
Higgs said. “Even with this increase in performance we have
less stress on the standard components and hence a larger safety
margin.”
“The new XP-408 Advanced Competition engine is a true top-end
engine created for the homebuilder who wants the absolute highest
quality, efficiency and performance that a four-cylinder engine can
reliably deliver,” Steve Noujaim, Marketing Director for AC
Aeronautical LTD. “Whether they are flying for fun or
competition, this amazing engine will live up to their every
expectation. I’m sure performance-minded pilots who want the
best for their homebuilt will find it fills a very special need in
the market.”