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Posted for "Jabe Luttrell" <JabeLuttrell@comcast.net>:
Hello Walter,
I'd like to correct your misinformation you may have about the IOF550
tuning. The PowerLink(TM) FADEC engine is tuned to operate at the minimum
fuel flow that achieves the maximum power at all power levels above 75%
(called Best Power), including takeoff and climb. It monitors cylinder head
temperatures and exhaust gas temperatures and enrichens the mixture if the
temperatures exceed control limits (the control limits are less than rated
limits). Its maximum enrichment is the rated full rich mixture. With
appropriately constructed baffles you know that the limits will not be
reached in climbs and the engine will operate with considerably less fuel
flow than a manually controlled engine while at the same time operating with
higher power.
The FADEC controlled engine is also tuned to operate at minimum brake
specific fuel consumption between 45% and 75% power (called Best Economy).
It has a cockpit switch to allow the pilot to select either the Best Economy
or Best Power operating mixtures for the range of powers between 45% and 75%
of rated power. This allows the pilot to select whether to go fast or far
at any cruise power setting.
Futhermore in cruise (between 45% and 75% power) the FADEC engine checks its
tune every time it detects the power level has stabilized. If it needs to
make an adjustment it does. The FADEC engine checks its directly monitored
temperatures and pressures.
It calculates a variable spark advance, dwell, and injection shot for every
cylinder for every combustion event. By doing so the FADEC effectively
achieves near constant EGT (constant mixture) during climb, without any
input from the pilot.
The injection method is true sequential injection--a fresh shot for each
cylinder for each intake stroke. No pilot can monitor an engine as closely
or control the engine on a cylinder by cylinder basis for each combustion
event, adjusting for the variations not only in operation and environment,
but also for the variations in air delivery to the cylinders.
What the FADEC does prevent the pilot from achieving is off-optimum mixture
control either for minimum fuel consumption or maximum power production. It
does allow the pilot to select any power level he/she wants and to pick the
optimal way to operate at that power level. The pilot just doesn't have to
remember X-degrees LOP or ROP and never misoperates the red knob. The pilot
has direct control of the throttle and can set any manifold pressure. The
PowerLink(TM) FADEC operates equally well with single power lever or
separate throttle and propeller controls.
There has been a thread about range on the LML. The FADEC controlled
engines in flight have demonstrated from 15% to 20% less fuel flow in side
by side (formation flight and also in a twin--manual and FADEC on the same
plane) comparison with manually controlled engines. That equates to bigger
fuel tanks, or more payload, or money in your pocket. What isn't immediately
obvious during engine operation is that the FADEC engine also produces a lot
less lead and carbon sludge than the manually controlled engine. This means
your oil stays cleaner longer. The spark plugs stay cleaner longer. There
is no magneto repetitive service to perform. This equates maintenance cost
savings.
The PowerLink(TM) FADEC is available and has been FAA certified on the TCM
IOF550B,D,E,F,G,N cross flow and updraft engines, the TCM TSIOF550E, the TCM
IOF240B, the Lycoming-Superior-Mattituck IOF360 engines (angle and parallel
valve), 12 and 24vdc, 180HP and 200HP, the Mattituck TMX-320 engine, and
some variants for fellows who weren't satisfied with those choices. It's
the only thing you'll put on your airplane that will pay you back by
reducing your costs over any other powerplant choice.
There was a thread re: diesels for the Legacy. It was reported that at
100HP it was burning 5 to 6 gph. The FADEC IOF550,too, will burn 5 to 6 gph
at 100HP. It will also produce more than 300 HP. In summary the PowerLink
(TM)FADEC achieves excellent efficiency whether for range or speed.
I put the PowerLink(TM) FADEC in my Legacy.
Happy Flying,
Jabe Luttrell
N550JL
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