AOPA Pilot Magazine - August 2013 - 14

LETTERS
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

Twinosaurus?
Not extinct yet

Don’t give me double trouble
B y Dav e H i r s c H m a n

With performance on tap

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

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

www.aopa.org/pilot AOPA PILOT | 89

I found the “Twin Android arrives
v e r s u s S i n g l e ” I liked Ian Twombly’s story
debate entertaining, about Android aviation apps,
and even more the news that
thoughtful, and fun. Android is becoming respectaviation software
Probably the most able in the (“Products”).
community
enjoyable article in
I run the Android version
of an app named simply “Air
the issue. Routinely, Navigation,” which I regard as
the “Dogfight” fea- very useful. For me, as I fly about
equally in Western Europe and
ture is my favorite.
in the United States, it has the
Gregg Solove
AOPA 5942573
Albuquerque, New Mexico

Twin vs. single
Dave Hirschman made good
points for the single, and I
would like to add one more
(“Dogfight”). In a twin, you
spend a great deal of time trying to keep it in the air. By
the time you have cleaned
up and still cannot keep it in
the air, you have lessened the
available options for a safe
landing. Keeping it in the air
uses up all of your initial work;
looking for a safe landing spot
is left to the last minute, leaving
little to choose from.
With a single, the very first
thing you do is set up for the best
possible landing (where your
options are at their maximum),
with an attempt at a restart left
to time available. This is one of
the main reasons why a single
engine out is more successful/
survivable compared to a twin.
K. Carl Milbrodt
AOPA 508927
McBee, South Carolina

Owning and flying a twin is
the pinnacle of aviation. After
years of working up the ladder,
mostly in Cessnas, I finally was
the owner of Twin Comanche
7750Y, Piper’s brochure airplane for 1966.
After flying and maintaining
her for 400 hours, I came to
some conclusions. One is the
feeling of being sandwiched
between two hot engines
surrounded by 90 gallons of
fuel and only a little opening window on my side: I like
big doors. Another is the vulnerability of sitting behind a
hollow nose: I like the protection of an engine and whirling
prop in front of me. If you have
to maintain two engines, you
might as well have two airplanes; we now fly a Super Cub
and a Cessna 180.
Rod Rawson

AOPA 871128
Ellenton, Florida

AOPA ONLINE POLL: In the June issue of AOPA Pilot
magazine, former Technical Editor Pete Bedell and
Senior Editor Dave Hirschman have a dogfight: twin
versus single engine. Which do you prefer?

Single 70%

14 | AOPA PILOT August 2013

Twin 30%

advantage of covering both (as
well as much of the world).
The Android version
lags the iPad in functionality.
However, I have flown with a
friend using the same app on
his iPad2, and we found that the
iPad froze and crashed while my
tablets kept running smoothly.
Also, he needed an external
GPS, which I did not.

the real question is, Why can’t
our very expensive airplanes
have a fuel indicator that accurately indicates fuel in the tanks?
Or, I would ask the question a
different way: Why is it that the
FAA allows these airplanes to not
have an accurate fuel monitoring
system? My understanding is
that the FAA only requires the
fuel gauge be accurate when it
reads “E.” Really?
Our transducer-fed computers are great...so long as all
the fuel is going through the
transducer (and it was properly
calibrated). Leave off the cap
on a tank before takeoff, and all
bets are off. Have a sump valve
leak—or another form of leak—
and you are equally likely to be
surprised. All of which come
down to this: We need accurate
fuel tank gauges.

Running on hope

We welcome your comments.

Jean Claude Dispaux
AOPA 789907
Saint-Legier, Switzerland

I appreciated Tom Haines’ article (“Waypoints”). I love having
a good on-board fuel monitoring
system. In fact, I consider it as
important as a backup AI. But,

Larry Bloom
AOPA 1215319
Safety Harbor, Florida

Editor, AOPA Pilot, 421 Aviation
Way, Frederick, Maryland 21701
or email (pilot@aopa.org). Letters may be edited for length
and style before publication.

HANGAR TALK

P&E

“When an approach
isn’t looking good, we’re
taught to go around. At
airshows, however, procedures are often modified
to move traffic,” says
AOPA Foundation President BRUCE LANDSBERG.
In “SAFETY PILOT LANDMARK ACCIDENT: SET-UP
STALL” page 74), an acci-

dent at AirVenture proves
that it ultimately falls to
the PIC to determine how
much he or she is willing
to compromise.

“I heard Diamond’s
performance claims
about its new DA42-VI
and I was skeptical,”
says Senior Editor IAN
J. TWOMBLY. “But with
impressive cross-country
numbers coupled with
easy flying characteristics that have the ability
to bring twin-operations
mainstream, Diamond
nailed it.” See “NOT YOUR
FATHER’S AIRPLANE” on
page 50.

http://www.aopa.org/pilot

AOPA Pilot Magazine - August 2013

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