AOPA Pilot Magazine - July 2013 - 64
PROPULSION / PISTON
WHERE DO WE GO
(AT THREE TIMES
Electronic ignition fires up an O-320
B Y D AV E H I R S C H M A N
’VE LONG DESIRED TWO SEEMINGLY UNATTAINABLE attri-
64 | AOPA PILOT July 2013
In flight, the first noticeable difference was how
smoothly the engine ran. It’s impossible to quantify, but
In a cruise climb at 100 KIAS in the RV–4, fuel flow
(12.5 gph) and engine rpm are unchanged, but the rate of
climb increases about 10 percent.
Level at 7,000 feet, full power results in almost identical indicated airspeeds (154 and 156 KIAS respectively at
11 gph and 2,450 rpm), but the EGT spread between the
hottest and coolest cylinder is far narrower with electronic ignition (100 degrees F instead of 300).
The efficiency improvement becomes dramatic when
leaned for normal cruise. At 75 percent power (23.5
inches manifold pressure, 2,400 rpm, and 145 KIAS), fuel
flow settles at 8 gph (down from 9.0 gph with mags).
At a more economical 65 percent power (22 inches mp,
2,200 rpm, and 135 KIAS) fuel flow drops all the way to a
miserly 6.0 gph.
When you do the math, the high cruise setting (75
percent power) works out to about 23.5 statute mpg—
and low cruise (65 percent) yields an astonishing 29.5
mpg. That’s better than my car does on the highway,
and the airplane goes three times as fast, in a straight
line, with no traffic lights or stop signs, and is just way
more fun. Much greater efficiency is still available by flying higher and incorporating newer technology such as
matched fuel injection, electronic fuel injection, or even
Making the change to electronic ignition isn’t trivial
from a labor or cost standpoint. Two E-Mags plus harnesses, adapters, and new spark plugs cost about $2,750.
But periodic magneto service and timing are a thing
of the past, and replacement spark plugs cost $3 each
instead of $35. (By comparison, two new Slick magnetos,
new harnesses, and new spark plugs sell for $2,800.)
But after making the change, my biggest questions
are: Why didn’t the aviation industry adopt this technology a long time ago?
And what’s holding us back now?
butes from aircraft engines: Starting should be as
easy as my car, and flying miles per gallon ought
to be comparable, too. (My 10-year-old Chrysler
Sebring averages 24 mpg.) Sure, it sounds crazy. But
we can dream, can’t we?
The Lycoming O-320 in my Van’s Aircraft RV–4
is carbureted, so starting is seldom an issue, but it
occasionally gets cantankerous and requires excessive
cranking. Airborne mileage is typically about 20 mpg—
good, but not great for a 1,000-pound airplane.
The low-hanging fruit for improving engine efficiency
is electronic ignition, and after many years and hundreds of thousands of safe flying hours in Experimental
and Light Sport aircraft, meaningful progress is finally
coming to the FAA-certified fleet. ElectroAir last year
became the first to get its one-mag/one-electronic-ignition solution approved, and other firms including GAMI,
Champion, and E-Mag are pursuing their own answers
for a broad range of aircraft engines.
I decided to install dual E-Mags to get the full benefit
of two electronic ignitions and avoid changing the existing aircraft electrical system (which has one battery and
one alternator). Also, Engine Components International
(ECi) has made dual E-Mags standard on new Experimental-category Titan engines, and they are getting
very positive results in the field.
A few days after placing an order, a box arrived from
E-Mag with an installation kit and instructions that said
it would take between four and six hours to put them
in. That turned out to be optimistic as each installation
requires a small preinstallation scavenger hunt for the
proper hoses and fittings unique to each aircraft. But
under the guidance of A&P mechanic Carlo Cilliers, the
magnetos, wiring harnesses, and spark plugs were soon
gone from my Lycoming O-320 E2A, and two shiny EMags and replacement automotive spark plugs were in.
From a pilot’s perspective, the performance improvements with electronic ignition were apparent from
the moment I first turned the key. The engine started
instantly and idled smoothly. At 1,600 rpm, moving the
key switch to isolate the left and right ignitions showed
a tiny 20 rpm drop. And when I switched off the electrical master, the engine continued running normally. (Each
E-Mag ignition has an internal alternator that supplies
electricity continuously if the ship’s power is ever lost.)