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Operating Lean of
Peak (LOP)
With the Ultimate Bar Graph (UBG-16)
The UBG-16 provides many excellent features to help you operate your engine on
the lean side of peak (LOP).
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Begin by
placing the UBG-16 into the “Lean” mode. As a cylinder reaches peak EGT, the
appropriate cylinder number (located over each row of bars) will blink. A
blinking cylinder number indicates that a cylinder is operating lean of peak
(LOP). A non-blinking cylinder number indicates that a cylinder is operating
rich of peak (ROP). Also, if a cylinder reaches a “false” peak (as some do),
the UBG-16 will detect it as a false peak, and will not blink the cylinder
number until that cylinder’s true peak EGT is reached. With just a quick
glance, the UBG-16 will tell you if your engine is running at LOP or ROP. |
| During LOP
operation, the last cylinder to reach peak is the one of interest. This is
the richest cylinder as well as the one closest to peak EGT. It is important
to keep this cylinder running lean of peak (LOP) and to know exactly how
many degrees it is BELOW peak. If this cylinder’s mixture drifts and becomes
too close to peak EGT, it’s CHT and power will also increase. |
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Ten-degree EGT bars (as some bar graphs have) are inadequate for properly
monitoring LOP operation. The UBG-16 displays the temperature below peak to
one-degree resolution (as shown on the digital display in the picture to the
left). Any drift in temperature will be displayed immediately, allowing for
a prompt correction in the mixture. THIS IS IMPORTANT FOR PROPER LOP
OPERATION.
The UBG-16 can be left in the “Lean” mode during the entire cruise portion
of the flight, providing an ongoing view of the engine’s LOP operation for
each cylinder. IF YOU CHOOSE TO RUN AT LOP, THIS IS AN INVALUABLE TOOL. |
| Another
unique feature of the UBG-16 is its ability to alternate the digital display
between the absolute EGT reading and “Temperature Below Peak” for each
cylinder. Also, unlike other bar graphs, the UBG-16 will not alter the bar
graph display or lose the CHT readings during the leaning process. While the
digital portion of the UBG-16 displays the temperatures below peak for each
cylinder, the bar graph portion of the UBG-16 always displays the absolute
temperatures for all the EGTs and CHTs. If you are going to monitor the
drops in CHTs during LOP operation, this feature is absolutely necessary. |
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The UBG-16 provides an
additional display that shows the fuel/air mixture profile for your engine.
This display allows you to see how close all of the cylinders are to
reaching Peak EGT at the same fuel flow. In other words, you’ll be able to
see how closely the injectors are balancing your engine’s fuel air mixture.
The cylinder displayed with the lowest number of bars is the one that
reached peak EGT first. The cylinder with the highest number of bars is the
one that reached peak EGT last. Each bar above the bottom row of bars
represents 5 degrees F. This fuel/air mixture profile is generated
automatically and is an accurate graph of the true lean to peak temperature
spread between the cylinders. This feature is an excellent tool for
fine-tuning your injectors and does not require a paper, pencil, charts or
co-pilot! |
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