Leaning:

G Series is the best technology available, there’s nothing else like it, nothing even comes close to the advantages provided by the G Series. Operation lean of peak requires special information that only the G3 or G4 Graphic Engine Monitor can provide. The G Series instruments are extraordinarily capable yet easy to use. G Series specialized innovative leaning process is the first and only one to ever earn a patent, which may be read here.
The G series is unprecedented in its sophistication, and it makes a complex process easy to accomplish. Leaning with reference to temperature only is just too confusing for LOP. Our specialized process reports each individual cylinders status in unambiguous form. You needn’t ponder if a cylinder is rich or lean, the G Series will display that too.

 

Injector Analysis:

Nozzle flow uniformity is paramount to operation lean of peak but only Insight delivers a nozzle analysis every time you lean. G Series can forewarn of problems and assure uniformity of results. Of course other systems just leave you in the dark.

 

G Series Data:

G Series instruments are not just temperature indicators, they compute real-time results using manifold pressure, RPM, fuel flow and temperatures. G Series handles the raw data to eliminate confusion and provide answers. It couldn’t be easier. While constantly displaying critical information during flight the G Series always work diligently behind the scenes too, logging data to a handy SD card for study later so nothing is missed. It’s easy to go back in time, study trends and trace problems to root cause.

Innovation:

Decades ago Insight introduced the first instrument to display cylinder and exhaust gas temperature of all cylinders simultaneously. This innovation eventually became the industry standard as all other manufacturers followed suit.Engine monitors depend on numerous temperature probes that have equal potential to inform or confuse when any of them fail. In fact probe failures can easily be confused with engine failures. Only the G Series has a  probe diagnostic system built in.

Manufacturing G Series at Insight

  

 

Insight's 610C Graphic Engine Monitor (G3) color-coded bargraph and digital values may be Primary for CHT, EGT and TIT. All other data shown in cyan at the top of display are to be supplementary.

Traditional multi-cylinder exhaust gas and cylinder head temperature systems that force the pilot to switch or scan an indicator from cylinder to cylinder in search of critical engine data, are long obsolete. Using the latest computer technology, the G3 presents a clear, concise, graphic picture of all engine temperatures simultaneously for interpretation at a glance.

Never before has so much engine diagnostic information been available to the pilot and never before, has the pilot been able to control mixture with such ease and precision for peak fuel efficiency.
Insight's latest G3 automatically records flight temperature and will also interface with other data sources and report information to other instruments like MFD’s. The data-log files stored on the SD card can be easily retrieved by the pilot, in-flight or post-flight, for instant viewing or permanent record-keeping.
The G3 is a sophisticated tool for engine management. Its microprocessor performs many tasks that used to be handled by the pilot. One of the basic functions performed by the G3 is monitoring exhaust gas temperatures for all cylinders with one degree resolution. What is important is the exhaust gas temperature of a particular cylinder in relation to its peak. But peak EGT is not a constant; it changes with atmospheric conditions, altitude, power setting and engine condition and for this reason absolute exhaust gas temperatures in degrees Fahrenheit are quite meaningless.

The real objective of mixture management is finding a mixture setting which represents the correct position on the EGT/Fuel Flow Curve. As we will see later, this abstract task is easily accomplished by the G3's microprocessor which samples EGT's for all cylinders many times a second and subjects this data to a complex mathematical analysis can identify peak. This capability allows the pilot to operate his or her aircraft engine at the most economical mixture settings.

It is generally known that EGT can be a valuable source of information for engine diagnosis and troubleshooting, but there is a great deal of confusion when it comes to interpreting this data. One of the basic principles of EGT engine analysis is that engine temperatures (EGT and CHT) achieve equilibrium in an engine operating at a constant power and mixture setting. What is often overlooked is that this equilibrium cannot be defined as a single point but rather a range of temperatures.

The Graphic Engine Monitor (G3) is ready to operate the moment electrical power is applied. Within seconds after starting the engine, the white EGT bar graph columns will begin to appear on the G3 display. Each column corresponds to the Exhaust Gas Temperature (EGT) of a cylinder. The lowest exhaust gas temperature that can be displayed by the G3 is 800° F. In some engines, the throttle will have to be opened to the fast idle range to get an EGT indication for all cylinders. As the cylinder heads begin to warm up, the display will indicate Cylinder Head Temperature (CHT) for all cylinders as a smaller green bar in each EGT column. A horizontal red line across each column represents the maximum allowable CHT. Digital numbers below each bar graph column indicates the exact EGT and CHT for each cylinder.

G4 Twin Buss Voltage

The G4 Buss Voltage attempts to display the buss voltage in green when it’s normal and red when it’s outside of normal. In an aircraft with a 12V electrical system the Buss Voltage will be annunciated in green so long as the voltage is 12.0V to 14.9V (inclusive).In an aircraft with a 24V electrical system the Buss Voltage will be annunciated in green so long as the voltage is 24.2V to 28.7V (inclusive). Below this range the alternator isn’t charging the battery and above that it’s overcharging, and the Buss Voltage will be annunciated in red. The instrument must be connected to the main voltage buss (not in series with something else, on a lighting buss, etc.) and must have a good low-resistance ground connection, otherwise the voltage measurement itself will be in error causing the Buss Voltage to indicate in red erroneously.

Controlling the G3 instrument

The instrument has two control knobs that operate combination rotary and push button switches. The top knob in general controls screen selection while the bottom knob controls items within the given screen. Each screen assigns its own functional needs to the controls that may change depending on context. A screen may also label the controls with guidance information like “Push to exit”.

The Bar-Graph Display Screen

The Exhaust Gas Temperature is displayed in white bar graph form and is interpreted much like a conventional mercury thermometer. The higher the bar, the higher the temperature.
The cylinder head temperature is displayed in green single-bar format. During normal operation it shows as a green illuminated bar in the lower half of the bar column. Since EGT is normally higher than CHT, the green bar which represents CHT is on top of the white illuminated EGT bar and stands out clearly. However, when the engine is shutdown, the EGT quickly drops to zero and the cylinders remain warm for sometime.
The G3 provides a reliable indication of cylinder head temperature even with the engine shut down. Should an EGT probe fail, the entire EGT column for that cylinder will go blank, and the numeric indication will show --- that is dashes, but the CHT bar will still remain green. The failure of one probe will not affect the display of any other probe.

An Easy Upgrade

A key requirement of the G3 design was compatibility with previous GEM’s. We strive to never leave our loyal customers behind. Packing all the functionality of the G3 in package half the size of the original GEM took us to the limit of our patience many times but it was worth it. Fortunately its amazingly compact circuits will be built by robotic machines because most of the parts are too small to handle and too difficult to be seen by eye. Products like the modern cell phone have driven the electronic assembly technology we use a long way.

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Restarting The Leaning Process

Restart the leaning process and resetting the peak indications on G1 by short push of bottom button.
Restart the leaning process and resetting the peak indications on G2/3/4 single by a short push of the SEL button.
Holding the SEL knob for about 3 seconds on G4 twin will take you back to twin-engine screen.

Probe Screen

The Need for better Diagnostic Tools

Even the first GEM could detect an open probe and blank its indication. Over the years by helping owners and their mechanics trouble shoot instrument problems I developed a new understanding and sympathy for the challenge they faced.

Troubleshooting avionics is an expensive and time-consuming process. Often times the procedure requires access to the instrument connector for continuity measurements. This might take hours of instrument panel disassembly just to touch the connector. We needed something better, easier to use, less time consuming and therefore less expensive.

Why not have the instrument diagnose itself? Then you don’t have to disassemble the airplane or even touch the wiring. This is not as easy as it might seem. Adding resistance measurement hardware for each and every probe wire would more than double the complexity of the measurement system. I considered this carefully during the development of the GEM-610 second generation instrument. It would at least add a second PC board to the instrument and have even greater adverse impact on the GEMINI twin version. Even if we endured these problems to get the information we had no practical way to display it on an orange bar display.

So I abandoned it then, but revisited again this time. The new color display was certainly adept at displaying the information, eliminating that problem, but the resistance data was still hard to get.

So this time I was able to invent a new way of measuring resistance. The simple idea worked beautifully without adverse impact on the design. It was so simple in fact even I was skeptical at first.Without this simple breakthrough we’d still be diagnosing things the hard way.

So what does the diagnostic system do?

The probe diagnosis page indications are in green for normal readings and red for readings that fail the criteria set at the bottom of the screen. 

Each temperature probe consists of two wires, a positive lead and a negative lead. The two numbers next to each identifier show the resistance in Ohms of each lead. 
For example, the line EGT1 8 3 means the positive lead of the EGT1 probe has 8 Ohms resistance, and the negative lead has 3 Ohms resistance.

When the probe is new, it will have relatively low resistance. 
As the probe ages, it’s resistance will slowly go up. Eventually, the probe will measure outside the pas/fail criteria you set at the bottom of the screen, and change from green to red, indicating that the probe should be replaced before it fails and leaves you with no temperature reading at all.

One other point to consider is that the longer the wiring to the probes, the higher its resistance. 
Every foot of EGT wire adds 1.7 Ohms/ft for the + lead and 0.8 Ohms/ft for the - lead. Every foot of CHT wire adds 0.8 Ohms/ft for the + lead and 1.2 Ohms/ft for the - lead. 
A 24 ft harness will fail the criteria that an 8 ft harness will pass with. That is why we allow the user to modify the pass/fail criteria on the bottom of the screen.

The meaning of the pass/fail criteria is as follows:
R MAX sets the maximum resistance (in Ohms) that any single lead may have. If the R MAX is set to 20 Ohms a probe with either the positive or negative leads measuring greater than 20 Ohms will be annunciated in RED, otherwise its displayed in GREEN.
R DIF sets the maximum resistance (in Ohms) that the positive lead may differ from the negative lead. If R DIF is set to 10 Ohms, the positive and negative leads need to measure within 10 Ohms of each other to be annunciated in GREEN, otherwise it is RED

EGT Variation Screen - View Mag Ad.

This is a new form of engine analysis.

Some valve related engine faults produce a slow periodic variation in EGT. The oscillation rate is on the order of one cycle every minute or two. This is just too slow to be identified by occasional observation of the temperatures alone. Yet it is very important to discover this phenomenon because it may lead to a catastrophic engine failure. It readily appears in a slow sampled spectrum analysis. 

Temperature samples are collected once per second for each cylinder and analyzed each second. The entire sample interval is about 8 minutes. A normal indication will be a flat line with a little noise, while a trouble indication will show as an obvious spectral peak.

Vibration Screen

New Capabilities for the Next Generation G3 GEM

If you take a step back from the EGT/CHT idea to explore engine monitoring in general, you discover that at least half the engine monitoring solution is missing. EGT analysis reveals combustion phenomenon but simply ignores mechanical problems.

By the time a mechanical problem shows up in EGT, if it ever does, the damage is done and it is far too late to do anything about it.

Vibration analysis is the key to pre-emptive detection of mechanical problems.

Following the update of the G3 Graphic Engine Monitor to V1.78 or higher, the Vibration Analysis screen will now appear among the supplementary screens when the PG knob is turned. In order for the vibration analysis to function your G3 must be equipped with a vibration sensor and a connection to the magneto for RPM measurement. If your instrument was purchased prior to September 2011, Insight will be sending you a vibration sensor shortly. Instruments purchased after this date will ship with the sensor included with the main kit.

After the electrical connections to the sensor are made, then sensor may be tested simply by powering up the G3 and vibration sensor. It is not necessary to start the engine to perform this test. The sensor LED should flash briefly and rapidly when power is first applied until communication is established with the G3, at which time the LED blinks more slowly (approximately once per second). When the LED indicates communications with the G3 has been established select the Vibration Analysis screen by turning the PG knob. While observing the vibration graph disregard the “RPM Required” message and rap lightly on the vibration sensor with the handle of a screw driver. The graph should register the impacts.

The sensor should then be firmly mounted directly to the engine case, preferably oriented in such a manner as to match the small airplane symbol engraved on the sensor body. In some rare cases it may not be possible to mount it in this manner, and the installer will have to fabricate an appropriate bracket or else be prepared to compensate for the change in orientation when viewing the vibration data. A representative installation is shown in the following figure:

Using the Vibration Analysis Screen on the G3:

The sensor detects vibration in all 3 axis (fore-aft labeled x, up-down labeled z, and left-right labeled y) which are presented on different sub-screens. The vibration analysis only functions when the engine is running and a valid rpm signal is detected.

In regards to the vibration graph, the vertical axis represents the amount of vibration energy and the horizontal axis represents the frequency spectrum expressed as multiples of crankshaft rpm. When the engine is running, the screen will come alive with a waveform that represents the engine motion, presented in a spectral format with the crankshaft energies appearing at the 1x mark on the bottom scale. Propeller vibration will likewise be synchronous with the crankshaft vibration. Other sources of vibration will tend to produce energies at other frequencies.

For example, camshaft vibration tends to accumulate at the .5x mark, since the cam turns at 1/2 the rate of the crankshaft. Magneto vibration will appear at 1.5x mark in a 6-cylinder engine. Alternator vibration may appear somewhere around 3x or 4x, depending on the ratio it is driven at.

A gear-driven alternator may appear in a different axis than the crankshaft does  if it is mounted at 90deg to the engine, although ANY source of vibration will show some energy in all three axis. Complex vibration as generated by reciprocating machinery will also produce a great number of harmonic spikes, which at first glance may seem confusing. The user should experiment with running the engine at different power settings under different conditions to get a feel for what is a "normal" spectrum for their particular engine.  A simplified case of vibration is shown in the following figure:

 

In the example shown above the main source of energy is at the 1x mark, and represents the crankshaft rpm. The smaller spikes at the 0.5x mark and the 1.5x point are probably created by the camshaft and the magneto, respectively. The user should be aware that a multi-cylinder reciprocating engine produces energies at a multitude of frequencies and directions, which reinforce and subtract from each other to create a very complex waveform. It is the responsibility of the user to gain familiarity with a waveform that is typical of their particular engine, so that unusual readings can be detected and interpreted.

The user may examine the various sub-screens by pushing the top button (PG). There are presently six screens to examine, each of the primary axis (X,Y and Z) and an averaged version of each (denoted Ax, Ay, and Az). The averaged version will be much "cleaner" and contain less noise than the raw measurement and is the preferred screen to examine for each axis. The bottom knob (SEL) controls a cursor which will "snap" to nearby vibration spikes to make it easy to examine them closer. The bottom knob can also be pushed to enter a zoom mode. When in zoom mode, turning the bottom knob will allow you to scroll through the waveform. Continue to press the bottom knob to set progressively higher zoom modes. A further press when at maximum zoom will return you to the overall view.

Pressing and holding the PG button will trigger the G3 to save the present vibration waveform for future reference. The waveform will be stored as a series of hexadecimal bytes in the current log file. Insight can provide a tool for examining this waveform using Excel or a similar spreadsheet. The tool is presently in the earliest functional stages of development, and will be improved over time.

It is expected that the vibration functions will be used as a "condition-monitoring tool". Since every engine and accessory combination is different, everyone's vibration spectrum will look unique and it would be impossible to generalize the interpretation of the spectrum. The user will come to recognize what a "normal" spectrum looks like for their engine and by periodically scanning the vibration screen can recognize when potential trouble is developing. When a new spike appears or an existing spike begins to show signs of higher than normal amplitude further investigation is warranted. The source of the spike can be interpreted by noting its primary axis and its frequency relative to crankshaft RPM as discussed above. By periodically saving their vibration data as discussed above, the user can create a database of reference waveforms for future comparison.

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While in-flight with the vibration screen showing on G3, Pressing and holding the PG button will trigger the G3 to save the present vibration waveform for future reference.

Insight announces the next big breakthrough in engine monitoring

In G Series Software Version 208 the G3-4 has a new page that displays data received from the TAS-1000.

The GEM's data-logging capabilities can be extended by receiving air data from a TAS-1000 air data computer. This page shows real-time air data which includes True Airspeed, Pressure Altitude, and Wind Speed and Wind Direction all of which are recorded in the GEM's data log along with engine and fuel data.

 

Insight’s G3-4 is now capable of receiving RS-232 serial data from our TAS-1000 MFDS that includes Indicated Air Speed, True Air Speed, Pressure Altitude, True Air Temperature, Wind Direction, Wind Speed, and Heading in the data log file on every flight.

While the detail in the G3-4 data log is unprecedented – now it is even better.

The G3 engine log system has been transformed to a complete aircraft performance logging system.

Now you can log aircraft performance data right along with your engine data.

The missing link in data log analysis is finally available.

Now you can really tell what’s happening. Much of the black-box functionality previously available only in Jets is now available to you.

The key to operating your aircraft efficiently is understanding its performance. Now every data log is like a performance chart from the flight manual but it is specific to your aircraft and actual conditions.

Don’t forget about the Insight TAS 1000’s ability to fill in your GPS pages with real-time air data, fuel, wind data page and also with wind arrow and wind speed on your moving map.

With no TAS the G3-4 displays only OAT (Outside Air Temperature) but with a TAS-1000 the missing link in data log analysis is finally available.

With the TAS installed in addition to OAT the G3-4 displays also displays

• TAT (Total Air Temperature)
• IAS (Indicated Air Speed)
• TAS (True Air Speed)
• ALT (Pressure Altitude)
• WD (Wind Direction)
• WS (Wind Speed)
• HDG (Heading)

NEW Fuel Screens

Previously, there was no standard color scheme in the configuration screens.

Now, the selected line is yellow and the inactive lines are white.
YES/NO in red has been removed by displaying only the word YES or the word NO in green, when saving.
When there is a choice of several items the selected item is displayed in green.
Exactly one item is always selected.
The choices of temperature units are Celsius or Fahrenheit then either Fahrenheit or Celsius will be selected in green.

The FUEL TOTALIZATION screen has been improved and is even easier to use.

This change allows the pilot to see this screen before entering fuel on board.
Also setting initial fuel can be checked and corrected in flight.
Previously the pilot had to enter the amount of fuel onboard before he could view the Fuel Totalization page.
Now both the FUEL TOTALIZATION page and the FUEL SETUP page are accessible at any time.
On the FUEL TOTALIZATION screen simply press the PG (left) button to enter fuel, press it again when done. As before you can top up the tank(s) by turning the SEL (right) knob counter clockwise on the very first click.

Set total fuel onboard before take-off

Your G2-3-4 was preset at factory with your usable total fuel

To reach the FUEL TOTALIZATION screen from the main screen:

• Turn the PG knob counterclockwise one click.
• Push PG knob to go back and forth between the FUEL SETUP and FUEL TOTALIZATION screens
• On FUEL SETUP screen setting fuel gallons the lines FUEL ADDED, SUBTOTAL and FUEL NOW color will be yellow.
• Turn SEL knob to set gallons (Clockwise or Counterclockwise one click for total preset total fuel for your aircraft)
• At any time, you can push PG knob to go back and forth between the FUEL SETUP and FUEL TOTALIZATION screens to add more fuel.

  

G3-G4 have same screens

 

FF Stability

Displays, literally, the stability of your fuel flow over the last few seconds. The smaller the number, the less the fuel flow has varied in the past few seconds. A well-regulated fuel system will have a small number, a carbureted system can expect a larger number. The smaller the number the more likely you are to get an accurate fuel flow reading during the lean-find function. An larger number will make things more difficult.

GEM FUEL TOTALIZER CAUTIONARY NOTICE

The Fuel Remaining display on the GEM is very useful but is not without limitations. Understand first that the factory fuel quantity gauges are the only instruments in the panel that physically measure fuel level. They are still the primary indication of fuel level in the airplane.

The GEM doesn’t measure level, but instead measures only fuel flow rate. The GEM totalizes the rate information to account for fuel used. If you know how much fuel you started with and how much you have used you can figure fuel remaining by simple subtraction.

The pilot must supply an accurate starting fuel level for this subtraction to produce the correct fuel remaining result. Should the pilot overstate the fuel quantity on board, the GEM will dangerously overstate the fuel remaining and the endurance time as well. The pilot must be careful and diligent when setting the fuel on board.

Getting the correct fuel total on board is in many cases pretty easy. If you fill up prior to takeoff the number is obviously the total available on board. If you partially fill a known configuration (say tips empty) then the total is easy to calculate. If you partially fill fuel tanks or add an accurately know quantity to a poorly known original value - errors will abound. Unaccounted fuel loss from leakage, fuel vent overflow or theft will of course produce erroneous results. So be careful and the GEM will deliver safe, reliable, and convenient fuel information. But be sure to cross reference the information on the primary fuel quantity gauges. Never trust a single source of fuel information when you have two on board. Fuel exhaustion still ranks highly among accident causes. Don’t let your engine stop until you’re parked.