AOPA Pilot Magazine - June 2013 - 89

P&E

DOGFIGHT: TWIN VERSUS SINGLE
There’s a new dog in our fight—welcome former AOPA Pilot Technical Editor Pete Bedell, a frequent contributor, airline first officer,
and co-owner of a Beech Baron. Let’s see how he handles his debate with Senior Editor Dave Hirschman.

Single supremacy
Don’t give me double trouble
B Y D AV E H I R S C H M A N
WITH TWO STARTERS, four magnetos, 12 cylinders, and 24 spark

plugs, it’s a minor miracle that piston twins manage to fly at all.
A lot of cantankerous machinery needs to operate in perfect harmony just to get a twin airborne. And when things go wrong—such
as in-flight engine failures—history shows piston twins are no safer
than afflicted singles. In fact, engine failures that result in accidents
are more likely to be fatal in twins.
That soothing rumble and hum of a second spinning disk may
make pilots and passengers feel good. But chocolate-covered raisins do the same thing for me, and “happy food” has as little to do
with the successful outcome of most general aviation flights as a
second engine.
We all know about asymmetric thrust and how it can contribute
to loss-of-control accidents in twins, particularly when an engine
fails at low altitude and high power just after takeoff. And we’ve all
heard the old saw about how the second engine is only there to take
multiengine pilots “to the scene of the crash.”
But piston twin shortcomings don’t stop there. Single-engine
service ceilings on many light twins are well below IFR MEAs (and
even terrain) in much of the western United States. Also, multiengine fuel systems can be confusing, especially when pilots are under
duress during engine-out emergencies that may require crossfeeding fuel to an engine on the opposite wing. And even when
everything is fine, visibility can be woefully limited.
Twin fans like to point to redundant
alternators and vacuum pumps as advantages. But many modern singles have
standby alternators (or electron-saving
essential buses), and glass-panel avionics
(new or retrofit) that are more reliable than
any mechanical AI. Electronic engine monitors (and oil analysis) can provide early
warnings of impending engine trouble.
My friend Pete Bedell believes he’s
doing his engines a favor by babying them
at low power settings—but that’s a dubious
claim. The longest-lived piston engines can
be found on hard-working primary trainers because frequent flights contribute to
their longevity, not kid-glove treatment. An
aged piston twin that flies irregularly (like
so many these days) is double trouble.
There are some intriguing experimental twin designs such as Velocity’s V-Twin
and Burt Rutan’s wild-child Boomerang
that seem to deliver real performance and
Continued on page 90

Twinosaurus?
Not extinct yet
With performance on tap
BY PETER A. BEDELL
WHAT LUNATIC sticks up for twins when fuel is $6 per gallon?
Bear with me. Although painful at the pump, twins bring their
owners tremendous operational flexibility, load-carrying ability, redundancy, and—yes—even safety when in the hands of a
well-trained pilot.
There was a time when pilots were regularly killing themselves
in twins in the name of training. After the FAA cracked down on
training buffoonery, those accidents largely stopped. In normal
operations, a twin spends only a few seconds of every flight in that
critical regime from liftoff to about 400 feet agl where an engine
failure is a serious problem. The entire flight in a single is critical.
I surmise that Mr. Hirschman’s hairstyle came from constantly
worrying about what to do when his one motor quits.
There’s no denying the fact that flying over vast expanses of
trees, mountains, and water—especially at night—is basically a nobrainer in a twin. Any pilot of a single who isn’t worried when
flying over such terrain is delusional or still possesses the mind
of a teenager.
Where true twins (those with double the power of their singleengine counterparts) really shine is in takeoff/climb performance
and load-carrying ability. Excess power is on tap to haul as many
as six people, their luggage, and four hours of fuel off of sea-level
runways as short as 2,500 feet. Good luck
doing that in any single short of a Pilatus
PC–12. Owners of complex singles like to
retort, “I never travel with more than three
people, anyway.” That’s because they can’t!
Nothing like owning a six-seat airplane
where two seats never leave the hangar.
Once I haul that big load off the runway in my family’s Beechcraft Baron, I can
fly almost as efficiently as today’s complex
singles thanks to GAMIjectors and lean-ofpeak EGT operation. My twin Continental
IO-550s loaf along at about 55-percent
power, consuming about 20 gph total doing
170 KTAS—roughly the cruise speed of a
Bonanza running at 75-percent power ROP
burning 17 gph. Hardly “double” the fuel
burn in this case.
The bottom line in aircraft design is
that if you want to go fast, you’re going to
burn a lot of fuel. Look at the fuel burn of
a Cirrus SR22T, Cessna T206, or a Cessna
Continued on page 90

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