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RPM Sensor for Bendix Mag

Revolutions per minute (RPM) as displayed by the RPM indicator in the cockpit, is an indication of the amount of power provided by the aircraft’s power plant. As a general rule of thumb, higher the RPM, more the power and more the fuel consumption.

That said, more the number of cylinder’s in the aircraft, lesser the RPM indicated at the same speed on the RPM Sensor for Bendix Magneto indicator. This is obviously due to engine efficiency. A lower powered engine e.g. a 4-cylinder aircraft engine has to put out more RPM to generate the same speed as say an aircraft with a 8-cylinder engine.

Apart from the amount of fuel the pilot feeds into the engine, another factor that controls propeller RPM is something called the ‘Propeller tip speed’ and on most single engine aircraft, it is usually below 2,700 RPM. Aircrafts with longer propellers e.g. king air, the RPM would be around 2,000 because it would generate more thrust and therefore require RPM i.e. have better economy.

Again, as a general rule of thumb, higher RPM generally means more maintenances visits due to wear and tear on the oil seals, bearings and also breakdowns caused due to transmission fluid leaks.

Bigger (e.g. 8-cylinder) aircraft engines have lower RPM by design. Running a higher MP/lower rpm results in better cylinder compression, reduces frictional losses, improves prop efficiency at lower rotational velocities and, allows the valves to run cooler resulting in lower EGT Probes and TITs.

For all the above reasons, the RPM indicator and the health of the RPM sensor as also the Bendix Mag is important. As the aircraft ages, the RPM sensor could get dust coated, damaged and so forth. With age, the accuracy of the RPM being displayed on the RPM indicator might be suspect. We’ve seen RPM accuracy off by 100 to 200 RPM in 15-year old aircraft.

If your aircraft is due for an overhaul and the RPM sensor, indicator and Bendix mag is due for replacement, you might want to consider a better-quality RPM sensor for pressurized Bendix series. Simple in construct, the Bendix Magneto RPM sensors is easy to maintain, is cost effective and pairs well with the J.P. Instruments manufactured RPM sensor; which is highly accurate.

In relation to the Bendix mag, there is a rotating magnet inside it and it is important that it rotates at a speed that is within the prescribed range. If this does not happen, the voltage generated will be erratic and the spark plugs will misfire. This is where the RPM Sensor comes in. The RPM Sensor plugs into the magneto and transmits the data to the RPM indicator / display unit in the cockpit.

For purchase or more information, please visit: https://www.jpinstruments.com/shop/rpm-sensor-for-slick-mag/

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Here’s Why EDM 790 Is The Most Reliable EDM

The reliability of the EDM 790 is not just any tall claim by manufacturers J.P. Instruments. Tests prove beyond a shred of doubt that the Engine Data Management 790 system is truly the most reliable and advanced twin piston engine-monitoring instrument on the market. And, backing the reliability claim is the TSO certificate for quality.

Beyond all doubts, the EDM 790 can be counted as the best EDM for 4 or 6-cylinder aircraft engine that money can buy (incudes transducers).

EDM 790 tracks 29 critical parameters of the aircraft engine

Utilizing the latest microprocessor technology, the EDM 790 can monitor 29 critical parameters of the 4 or 6-cylinder aircraft engine and it does so 4 times a second!  The sensors attached to the EDM and also manufactured by J.P. Instruments, boasts of a linearized thermocouple accuracy of better than 0.1 percent or 2 F° - as tested and verified by the FAA.

The EDM 790 never sleeps

From the moment the pilot switches on the engine and throughout the flight, the EDM 790 will constantly monitor 29 critical parameters that are automatically checked 4 times every second. No matter which page of the display the pilot might be looking at, the EDM 790 will keep running checks on all 29 parameters in the background.

Sensor accuracy

Working alongside the EDM 790 are the all new linearized thermocouples. There is nothing in the aviation market that compares to the linearized accuracy of 0.1 percent or 2 F° - as tested and verified by the FAA.  

Programming Simplicity

The EDM 790 incorporates two buttons on the faceplate. All programming can be achieved via these two buttons. With the EDM 790 it is now possible to have substantially more diagnostic information available for your maintenance crew. Leaning is accomplished automatically using the LeanFind™ procedure.

Here are the Advantage of EDM 790

1. Capability to run computer assisted diagnostics from the cockpit. On detecting any error, the EDM will display a specific code. 2. Easy-to-use 2-button faceplate programming. 3. 29 critical parameters checked 4 times a second and this includes the Fuel Flow and Shock Cooling, EGT Differential and Alternator Voltage. 4. Displays variable Scaling of EGT as a Bar Graph. 5. It’s amazing PeakFind™ with quick responding probes, automatically captures the EGT or TIT peak value while the LeanFind™ Mode identifies the first and last cylinder to peak. 6. Data Port for convenience of downloading of data. 7. It includes a complete Fuel Flow Instruments. The EDM 790 is the only FAA approved graphic engine monitor in this class. 8. Unmatched accuracy - temperature detection accuracy is ONE degree (even for EGT). 9. This EDM is paired with JPI’s “grounded” fast response probes. 10. Every cylinder is covered – there’s cooling rate and shock cooling checked on each and every cylinder. 11. This Engine Data Monitor features a “Normalize Mode” for accurate trend monitoring. 12. Automated alphanumeric scanning display of 29 functions or channels. 13. Tested and carries a TSO certificate for Quality and Reliability with FAA, STC approved Fuel Flow. 14. Three-year warranty.

For more information, please visit: https://www.jpinstruments.com/shop/edm-790/

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CRB Probe and CHT Gasket Probe in Aircraft

All aircraft have a whole bunch of probes connecting various parts of the aircraft engine to the cockpit. The probes (or sensors), pickup the information it is supposed to pickup and transmits it in real time to the cockpit where it is connected to the appropriate indicator or Aircraft Engine Data Management (EDM).

CRB probe and CHT gasket probes are two such probes. The Carburettor Temperature Probe (CRB) probe transmits carburettor temperature while the Cylinder Head Temperature (CHT) gasket probes transmits the cylinder head temperature to the appropriate indicator / EDM in the cockpits.

As you might guess, irrespective of the weather or temperature outside the aircraft, the engine and every other vital parts of the aircraft, has to function at a temperature that is conducive to its smooth functioning. Overheating can lead to fuel ignition and fire whereas, a drop in temperature can lead to the engine stalling and dying out in flight due to fuel starvation.

Every pilot therefore keeps a wary eye on the CRB and CHT indicators. If the cockpit sports an EDM than the pilot’s task is made simpler as the EDM can be pilot-programmed to raise and alarm in the event of any abnormalities in the CRB and CHT readings. The pilot is therefore free to pursue higher cognitive functions.

CRB probe explained:

Every carbon fuel powered engine has a carburettor usually mounted on top of the cylinder. Inside the carburettor is where the fuel-air mixture happens before it is pumped into the cylinder. The fuel-air mixture has to be precisely both in terms of fuel-to-air ratio and as to the temperature of the mixture. Any deviation will lead to serious consequences inside the cylinder and for the aircraft itself hence the need to monitor the carburettor temperature.

J.P. Instruments manufacturers CRB probes that are immune to humidity or presence of oil and gasoline.  J.P.I CRB Probes are also engineered to withstand temperature fluctuations.

CHT probes explained:

Although there are three basic types of CHT probes, the one that we are concerned with, is the “J-type” CHT probe; also known as CHT gasket probe because it replaces the gasket on 18mm spark plugs.

You buy a CHT gasket probe if your aircraft engine does not have a threaded thermowell receptor. If you have difficulty adopting the CHT probe to your cylinder, you might want to look at the ‘CHT adapter probe’.

The CHT adapter probe is used in conjunction with the OEM CHT probe. The CHT adapter probe is a threaded probe that fits into the cylinder head thermo well and is available as a bayonet type or threaded type. So, you might want to take a look at the existing CHT probe and cylinder before buying the replacement CHT probe or CHT gasket probe.

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Implementation of PC Interface Cable

As 20-or-more-year-old aircraft are overhauled, no matter how traditional the owner might be, a certain degree automation is usually introduced into the cockpit. This is done in the interest of accuracy and also to enable some analytics for the ground crew. The modern day EDM for example, relieve the human operator of the tedium of continuous control and frees the pilot to indulge in higher cognitive functions. The older the Aircraft Engine monitor, the greater the need for the ground crew to analyse the aircraft performance.

The aircraft engine performance can be analysed in detail provided there is some way for the engine data to be stored and later retrieved. This is usually accomplished via onboard memory which is connected to communication ports. The latest aircraft engine data managers are usually equipped with USB ports thereby making it even easier to download engine data.

Before the onboard memory is full, the data should be downloaded and at least stored on an external hard-drive (via a PC or Laptop). At some point in time, the ground crew and connect the external hard-drive to their computer and analyse the data.

Assuming the cockpit has some degree of digital automation, transferring data accumulated onboard to a PC usually means connecting the display unit/ engine data manager via an interface cable to a PC computer. Earlier display units / engine data managers had serial ports.

One of advantages of using onboard digital indicators and data managers is the possibility of implementation of PC interface cable and providing a data link between the aircraft and ground facilities. The PC Interface Cable usually has a 9-pin serial connection male plug (may require external power supply). Laptops that do not have a serial port will require a Serial-to-USB Adapter so that the serial cable can be plugged into the adopter and the adopter in turn, can be plugged into the USB port of the laptop.

The hardware i.e. the PC interface cable is one part of the interface. The other part consists of the software that implements the hand-shaking protocol so the PC at one end, can “talk” to the indicator / EDM at the other end.

The software you use will be the one that was bundled with the hardware in the cockpit. If you did not receive the software in form of a CD in the product box, you probably need to download the software separately via the manufacturer / retailer website.

For example, J.P Instruments provides the EzTrends Plotting Software that is available as a download here : https://www.jpinstruments.com/technical-support/ez-trends-download/ 

This patented software will transfer compressed data from your EDM to your PC via the interface cable and decompress the data. Additionally, it will also plot the data on the PC screen and provide necessary user interface to print graphs and provides flexibility in how data is displayed.

For purchase and more information on PC interface cable, please visit : https://www.jpinstruments.com/shop/pc-interface-cable-for-edm-700-edm-800-and-edm-760/

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Installation of RPM Sensor for Slick Magneto

Pilots and owners of aircraft unless licensed as airframe and powerplant mechanics should ideally not be installing or doing maintenance work on their own unless supervised by competent person.

Before you decide to buy a new sensor, make sure the existing one hasn’t stopped working because of some silly reason.

Start with ensuring that the RPM sensor is fitted to the correct vent plug of the slick magneto. When you peep into the vent, if you see ‘gear’ instead of the rotating magnet, then the RPM Sensor for Slick Mag is fitted on the wrong vent.

If the RPM sensor produces a reading, it should be in this range:

3600 rpm for a 4-cylinder engine 2400 rpm for a 6-cylinder engine 1800 rpm for a 8-cylinder engine and, 1600 rpm for a 9-cylinder engine. 1800 rpm for a 4-cylinder dual magneto engine and 2400 rpm for a 6-cylinder dual magneto engine.

The red wire from the RPM sensor should be connected to a 5-volt supply.

Check for oxidation on the male/female spade connectors between the RPM sensor and the gauge harness. Sometimes, oxidation can result in intermittent RPM reading. Test the ignition wire boots and caps to check continuity.

If you are convinced that you do need to install a new RPM sensor for your Slick magneto RPM Standard Sensor for vent plug for Slick magneto (JPI part # 10-05652); start with:

1. The rotating magnet will have a vent plug – remove that. 2. Make sure you have removed the plug from the correct vent by: 3. Peeping into the vent and ensuring that you are not seeing the ‘gears’. You should only be seeing the rotating magnets. 4. Insert the speed sensor into the vent port and initially use your fingers to tighten then tighten 1/8 turn. 5. After installation, when you fire up the Aircraft Gauges, the RPM Gauges in the cockpit should be in the ranges mentioned above in this article. 6. Route the wires back towards the firewall – avoid attaching the wires directly to the ignition. 7. Sufficient slack should be provided in the wire bundle to allow for engine movement between the engine and the engine mount. 8. Connect the wires to the corresponding coloured wires in the instrument harness.

Once everything is installed, you need to test the engine prior to take off. Any malfunctioning in the ignition system can be identified by observing changes in rpm that occurs when the ignition switch is moved from “both” to “right” and then from “both” to “left”. A small variation (decrease) in engine rpm is normal during this test. The permissible decrease is listed in the AFM or POH.

If the aircraft engine stops running when switched to single magneto or if the rpm drop exceeds the prescribed limits, do not fly the aircraft until the problem is resolved.

It should also be noted that no variation in rpm is not normal and the aircraft should not be flown.

To buy the latest RPM sensor for Slick Magneto, please visit: https://www.jpinstruments.com/shop/rpm-sensor-for-slick-mag/

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The CHT Bayonet Probe – Features & Specifications

A CHT Bayonet probe is a threaded probe typically used on Lycoming engines in aircraft. These spring-loaded bayonet mounted CHT Probes are usually ‘K’-type probes and they generally include an adopter.

The CHT Bayonet probe are turned clock-wise and locked into the screw-in adapter and screwed into the cylinder head thermo well. Being spring-loaded, the probe has good contact with the metal of the cylinder. The k-probe is used when the aircraft engine has a bayonet adapter in the cylinders. It can also be used if the cylinder is equipped with threaded thermowell receptor.

CHT Bayonet probes are generally K-type because they have a wider temperature sensitivity. This is typically in the range of -200°C to +1250°C (-330°F to +2460°F). The sensitivity is approximately 41 µV/°C. Most TIT and EGT probes used in aircraft are of the K-type and the sensor is an amalgam of Alumel and Chromel – two metals that react differently but very precisely.

Typically, CHT Bayonet probes come in two flavours; non-grounded and grounded. The non-grounded probes have the thermocouple junction isolated from the probe shaft. This is done to ensure that there is no continuity between the thermocouple.

The grounded probes are just the opposite in that they have the thermocouple junction welded directly to the probe shaft. This results in a probe that has longer life, lower cost and faster response time. However, these grounded probes suffer from one disadvantage - they are susceptible to electrical noise which, unless rectified via special circuit in the gauge, could result in temperature readings that are slightly off the mark.

The CHT Bayonet probe is easily installed:

1. You begin by screwing in the threaded CHT probes into the cylinders.

2. For 4-cylinder Aircraft Engine monitor, thermocouple channels TC5 through TC8 are used. For 6-cylinder aircraft engines, thermocouple channels TC7 through TC12 are used.

3. In K-type thermocouples, yellow is positive and red is negative.

If you find that the wiring does not reach the cylinders, you can obtain CHT extension kits with k-type thermocouple wire, splice barrels, and a length of inner heat shrink tubing. Using heat shrink tubing eliminates all air inside the splice and makes an airtight seal. We recommend Raychem SCL-3/16 heat shrink tubing.

Extending the wires of CHT Bayonet probe in aircraft:

1. Using a wire stripper, strip the CHTs and make small loops with the ends; do the same for the k-type extension wire (if used).

2. Prepare the splice barrels.

3. Use the splice barrel and short length of shrink wrap on the wires.

4. Lay the CHT and k-type extension loops over each other.

5. Slide the splice barrel over the parallel loops.

6. Crimp the splice barrel with a crimping tool.

7. Slide the heat shrink over the splice and apply heat to the extent required so the heat shrink tube properly grips the joint.

8. You now have an airtight, solder-free and airless parallel thermocouple splice.

Visit here for more information:- https://www.jpinstruments.com/shop/cht-bayonet-probe/

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Oil Temp Probe In Aircraft And Its Advantages

Be it a car, truck, bike or a plane, most of us are just content in flying it or driving it. Not many have so much as seen the engine under the hood or even know what it looks like. And then, there are others who need to not only see but need to feel, to know what each part does and its importance in the entire machine. Today, let us consider the Oil Temp Probes in aircraft – their importance and advantage.

Just as the temperature of the human body is indicative of the health status of that body, so too in any aircraft, there are several locations that require the heat to be carefully regulated.

Some of these locations include carburettor (for testing temperature of the fuel mixture), engine oil temperature - over-heated engine oil could burst into flames or oil at low temperature will turn sluggish. Then there is the inlet air temperature (as it effects combustion), free air temperature, engine cylinder head temperature, heater ducts, and exhaust gas temperature of turbine engines etc.

The tip of the temperature probes is an amalgamation of two different metals that react in a precise measurable manner to temperature changes. These temperature probes are called thermocouple probes. Due to consistency of their reaction to heat, these types of probes are ideal for use in aircraft and other machines where precision is a must.

An aircraft engine requires a high level of precision and therefore, the quality of inputs including oil, matters a lot to the performance of the Aircraft Flow Sensors.

The temperature of the oil effects it’s viscosity and therefore flow rate and usefulness in lubricating the engine.

An oil temperature sensor is therefore vital to know the state of the oil in oil tank. The modern oil temp sensor or probe, is connected via wires to the EDM or oil temperature indicator. If the cockpit sports a modern EDM, the pilot can probably set an alarm for low/high oil temperature.

It is advisable that the oil temp probe be regularly tested for accuracy. This can be done by an expert mechanic who will spot gauge calibration errors and rectify the same or replace the oil temp probe.

Once the periodic testing is completed, it is best if the gauge, sensor, and interconnect wiring be calibrated before flight.

Installation of the oil temperature probe in aircraft

To install the OTP, first locate the pipe plug (usually found on the front of the engine inline with the push rods). After you remove the pipe plug, insert the probe supplied with the kit. When done, wipe the place with clean rag and check for leaks. Next, route the probe leads back to the cockpit along with the EGT wires. Attach these to the appropriate gauge or EDM.

Visit here for more information:- https://www.jpinstruments.com/shop/oil-temp-probe/

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Comparing EDM 790 And EDM 900 Systems

This article helps you compare the two EDM’s and select the one that fits your requirements and your budget. Both these aircraft engine data monitoring systems are manufactured by J.P. Instruments.

EDM 900

(Usually between $3,000 and $5,000)

Features:

2-4 piston Aircraft Engine Monitoring Includes Pre-wired Harness Includes CHT & EGT Probes and Harness Includes Oil Pressure Transducer and Harness Includes OT Transducer and Harness Includes Fuel Flow Transducer and Harness Includes OAT Probe and Harness Includes RPM Sensor and Harness Includes Manifold Pressure Transducer and Harness Includes Shunt 100 amp and Harness Includes Volts V1 and Harness

Features Remote Access Display 8 Alpha Numeric Characters. Backup display. Includes Plotting Software EZTrends © Capable of EGT Differential Span Hottest to Coolest Capable of CHT Differential Span Hottest to Coolest Shock Cooling on all cylinders Accurate Lean and over lean Horsepower GPS Interface to any GPS even hand-held Fuel Efficiency, Fuel Used for the Trip Fuel Used Since Fill up, Time to Empty Distance to Empty Fuel required to next Way Point or destination Fuel Reserve at way point or destination Flight Timer Tach Timer, Engine Hours Date, Zulu Time

The Engine Data Management 900 for aircraft has 4 operating modes; automatic, manual, Program and LeanFind.

More information here: https://www.jpinstruments.com/shop/edm-900-2/

EDM 790

(From $7,055.00 to $8,255.00)

Features:

EGT & CHT 4 or 6 probes Monitor and display of Volts Monitor Shock cooling Span (highest to lowest EGT) EGT Normalize mode LOP/ROP function Power connector All required Harness 20 ft EZTrends Graphing Software free Serial Data recording -25 hours 3 year Warranty Full Instrument: Width 4.81 Height: 3.47 Depth: 3.56 Insert Size 3-1/8 in panel mount 3.56 deep. Width Above Panel .80 Weight: 1 LB.

Optional Functions include: Fuel Flow, Oil Temperature 1 & 2, Turbine Inlet 2 (TIT-2), Outside Air (OAT) Carburettor Temperature (CRB).

Fuel Efficiency, Fuel Used for the Trip Fuel Used Since Fill up, Time to Empty Distance to Empty GPS Interface to any GPS even hand-held Fuel required to next Way Point or destination Fuel Reserve at way point or destination Data Port for downloading of data. FAA approved graphic engine monitor with a full Fuel Flow Transducer system. Extremely accurate temperature detection; ONE degree (even for EGT). Paired with JPI’s “grounded” fast response probes. Monitors the air craft engine every 2 to 255 seconds.

More information here : https://www.jpinstruments.com/shop/edm-790/

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EDM 830 – Full Colour Engine Data Manager for Aircraft

As the owner of a piston engine aircraft, whether you are upgrading your existing EDM or upgrading your cockpit, you can’t go wrong in selecting the full colour EDM 830.

The all new EDM 830 series engine data management system is an upgraded version of legendary 700 and 800 series EDM. Features of the EDM 830 include an easy-to-read 7-segment character display that is visible even during bright daylight.

Should there be any kind of engine problem, the pilot can quickly scan through and identify the source of the problem. The audio-visual alarm system also helps to quickly identify the cause.

Aided by its custom display that can display in portrait and landscape mode, the EDM 830 can adjust in any corner of the cockpit panel; even the button positions can be altered. This custom display system can be activated by holding down the white step button until you see an arrow. Thereafter, tapping the black-line button will turn the display. When done, the EDM 830 will reboot with the new orientation.

The new features that have been added to the EDM 830 include lean of peak default so whenever the pilot uses the lean fine mode, he can choose between rich of peak or lean of peak as his default start-up setting.

The all new full colour EDM 830 also includes user programmable gauges so the pilot can decide which Slim Line Gauges he would like to have displayed and the order of the display.

Additionally, with the new EDM 830 from JPI, the aircraft owner can enjoy improved fuel economy, reduced maintenance costs and extended engine life.

JPI is a leader in precision aircraft engine performance monitoring. Under normal circumstances, only a small percentage of combustion energy actually moves the piston that produces engine power. Most of this energy passes into the exhaust pipe as very hot gases. Monitoring this gas temperature with your EDM 830 will indicate the quality of the combustion process and the pilot can therefore troubleshoot potential engine problems.

Another interesting feature is the lean of peak or L o P feature that can save the owner money on every flight. The new EDM 830 constantly checks all critical engine parameters while the pilot concentrates on flying the aircraft. In fact, with the 830 the pilot can make an entire flight without ever pushing a button or opt to view only critical pieces of engine data individually.

The EDM 830 will monitor the aircraft engine and will warn the pilot instantly if any parameter exceeds the programmed limits. Furthermore, these limits can be programmed by the pilot via buttons on the faceplate.

The EDM 830 has a larger and richer display than the previous models. The EDM 830 displays both rpm and manifold pressure graphically and digitally percent horsepower is located in this display area. Additionally, the height of each column represents the EGT while the last pale blue column represents turbine Inlet temperature.

Visit here for more information:- https://www.jpinstruments.com/shop/edm-8301/

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EDM 900

This is no ideal claim and there’s a TSO certificate to prove the claims. With the advanced EDM 900 on board, you can remove many of your old analog gauges and reduce clutter on your instrument panel.Depending on space or user choice, the EDM 900 can be installed vertical or horizontally. Additionally, the owner has almost unlimited installation choices, and the device itself has a long list of user options to provide more control and information to the pilot.

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EDM 900 - Advanced twin piston engine -monitoring instrument

This is no ideal claim and there’s a TSO certificate to prove the claims. With the advanced EDM 900 on board, you can remove many of your old analog gauges and reduce clutter on your instrument panel.

Depending on space or user choice, the EDM 900 can be installed vertical or horizontally. Additionally, the owner has almost unlimited installation choices, and the device itself has a long list of user options to provide more control and information to the pilot.

Advanced data display:

To begin with, the display screen is divided into three parts – the top left is reserved for the Engine Rotation Speed (RPM) section and the Engine Manifold Pressure (MAP) data. To the right of the pilot, is information for primary strip gauges. The bottom left is reserved for messages i.e. the Scanner® alerts. The EDM 900 displays information in digitally in large very readable characters. The device comes equipped with range limits and pre-set alarms that are factory-configured to match the aircraft it is being fitted into. This does away with the need for any pre-configuration at the user end.

A new addition is the Remote Annunciator Light ‘RAL’ that provides notification that an alarm is triggered. On powerup, the RAL will first glow red and then yellow indicating that it is functional.

The EDM 900 alarm:

The EDM 900 alarm consists of three parts; the digital readout changes colour to yellow or red (depending upon intensity of the problem), secondly, the message area will display the error code and finally, just so the pilot does not miss it, RAL light will blink to gain pilot attention.

Features included:

The EDM 900 has a long list of function - only a handful are covered here.

The EDM monitors voltages, engine pressures and temperatures; it assists in diagnosing engine malfunctions and fine-tuning the air/fuel mixture. The programming is achieved via 4 buttons located on the panel buttons located below the display area.

The Scanner analog display including index square and cylinder numbers are displayed in the lower left corner. The bottom left is reserved for numeric readouts and messages. The Bar graphs will be displayed on the right half of the display screen. The height of each column (bar graph), digitally represents the temperature of the CHT or EGT or TIT (if installed).

Numbers are displayed below each bar graph column. These identify the cylinder for which the data is being displayed. Data for TIT (if installed), is identified by the letter ‘T’ displayed below.

The right side displays the linear bar graphs. These display oil pressure, temperature, compressor discharge temperature, Fuel Flow Instruments, tank fuel quantity (for both tanks). Alternatively, the same area also displays non-primary data including voltage, fuel pressure, fuel used, remaining and TOE (estimated), as well as OAT.

Although the EDM 900 display screen will automatically self-adjust to the brightness, the pilot can also manually adjust the brightness by taping on the ‘Dim’ button.

The Engine Data Management 900 for aircraft has four operating modes; manual, automatic, Program and LeanFind.

Called flight engineer because it provides the same data that earlier required a human flight engineer, the EDM 900 is truly a versatile instrument.

For more information, please visit: https://www.jpinstruments.com/shop/edm-900-2/

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Installation of EDM 760

The aircraft Engine Data Manager 760 (EDM 760), essentially consists of two parts – the display and the probes. While the display goes into the cockpit (obviously), the probes are attached to various parts of aircraft engine (or fuselage) depending on the nature of the probe. Each of these probes is in turn connected to the display unit via wires.

The EDM 760 uses slim line, fast-response probes that provide near instantaneous data to the display unit.

INSTALLING THE INDICATOR

Open the package and retrieve the steel template for the display unit. This template should be used as a guide for drilling two buttonholes in the instrument panel. The EDM-760 requires a standard 3.125" instrument hole. You do not have to worry about any configuration. The moment the pilot switches on the engine, the instrument configures itself automatically for twin 4 or 6-cylinder, 14/28-volt aircraft. The instrument is 7.5” deep (without connectors) and is 3.20 square behind the panel.

EXHAUST GAS TEMPERATURE PROBE (EGT)

The EDM 760 contains the Model M-111 probe. This will fit any existing holes in the exhaust stack in any engine having the diameter of 1/8" to 1/4". If you do not find any pre-existing holes, then, please drill a 1/8" diameter hole and ream to fit. Each probe should be mounted at a uniform distance from the exhaust stack flange (2 to 4 inches is recommended).

For accurate temperature data, ensure that the tip of the probe is in the centre of the exhaust stream. When sure that the IAT Probe is in the right place, tighten the stainless-steel clamp to a torque of 45 in/Lbs. Cut off the excess strap close to the screw.

TURBINE INLET TEMPERATURE PROBE (TIT)

The EDM 760 Kit will contain the P/N M-111-T TIT probe that has a special clamp. The TIT probe is placed in the exhaust stack accumulator to a maximum depth of 1/2 inch and approximately four (4) inches from the Turbine inlet. The TIT probe will appear as the seventh column “T “of the display unit and “1650 TIT” will be displayed when the dot is in place over it.

WIRING (12 / 24 volt)

Your EDM-760 is suitable for both 14 and 28-volt systems. Use the 15-pin connector to connect to the power lead. Ideally, you should insert a 2-amp in-line fuse connected to the avionics power buss. Once this is done, the pilot can use the avionics master switch to turn on/off the instrument during engine start-up. If there is no such switch, it might be worth your while and money to have one installed. The EDM-760 will self-test on start-up (takes 10-seconds).

Visit here for more information:- https://www.jpinstruments.com/shop/edm-760/

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CHT Probes Used In Aircraft

A CHT probe is used to obtain temperature data of the part of the engine in which the CHT probe is installed. A CHT probe is a thermocouple type probe – meaning, two different metals that react to heat, are joint together. When heated, a tiny voltage (millivolts), is generated.

As the heat increases, so does the voltage. The type of metals used depends on intended use of the probe. Essentially, there are three types of thermocouple probes; CHT, EGT and TIT.

CHT Probes in turn, are divided into J, K and E type probes.

Of these, the E-Type probes are obsolete and no longer used. Though, you might still find them in older EGT systems as in vintage aircraft. The E-type probe was usually made using Constanton and Chromel metals.

The J-type probes on the other hand, due to the metals used, are a type of CHT probes that are used in low temperature areas. However, the J-type CHT probe has a higher sensitivity and range. In fact, the range is 40°F to +1382°F (-40°C to +750°C). The J-type CHT probe has of approximately 55 µV/°C. These probes are typically made using Constanton and Iron.

Typically, the J-type probes are used in the manufacture of gasket probes. These probes are used on 18mm spark plugs. The 18mm gasket probe fits on many common spark plugs. It may be noted that radial engines such as the O-235 and O-200, may make it difficult to use the bayonet style adopter or may altogether prevent the use of a bayonet adapter. You should opt for the gasket style only if the engine model does not have a threaded thermowell receptor and or bayonet adapter in the cylinders.

Spring loaded bayonet mounted CHT probes are usually K-type probes. These twist and lock into a screw-in adapter and screw into the cylinder head thermo well. The probe is spring-loaded and helps ensure contact with metal instead of air. You use a k-probe if the engine has a bayonet adapter in the cylinders or, is equipped with threaded thermowell receptor.

The preferred CHT probes are the K-type probes because they have sensitivity over a wider temperature range. The K-type probes temperature range is -200°C to +1250°C (-330°F to +2460°F), and sensitivity is approximately 41 µV/°C. The K-type probes are usually used as TIT or EGT Probe. K-type probes are typically made using Alumel and Chromel.

You can also use the probes via the ‘CHT adapter probe’. These adopters are used in conjunction with the OEM CHT probes and helps to fit the probe into the cylinder heads thermo well. These adopters are available in two options – to accept threaded type OEM probes or, to accept bayonet type probes.

CHT probes are available in non-grounded and grounded options. Ungrounded probes have the thermocouple junction isolated from the probe shaft so there is no continuity between the thermocouple.

The grounded probes on the other hand, have the thermocouple junction welded directly to the probe shaft and therefore, have longer life and lower cost and faster response time. But, since they have continuity with the engine ground, they are susceptible to more electrical noise.

For more information, please visit: https://www.jpinstruments.com/shop/cht-bayonet-probe/

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Aircraft's Fuel Scan 450 Twin and its Awesome Benefits

The JPI manufactured fuel scan 450 Twin is one of the finest fuel management system for piston engine aircraft that money can buy.

For the pilot, the fuel scan 450 can be his personal flight engineer; always there working in the background constantly monitoring the fuel consumption while the pilot concentrates and enjoys the flight.

With its dual display system, the JPI fuel scan 450 displays the fuel flow rates on the upper display and other measurements on the bottom part of the display. The fuel scan 450 will easily interface with the panel mount or handheld GPS.

The JPI manufactured Fuel Scan 450 Twin uses two very reliable fuel flow sensors. Each of these sensors is mounted in the fuel line prior to the fuel distributor or carburettor and, they measure the actual fuel flowing through.

Internally, the JPI manufactured fuel scan 450 Twin consists of a turbine wheel that rotates at a rate proportional to the volume of fuel passing through it. The actual flow rate count is done via a light beam that gets interrupted by the rotating wheel. On the other side is a sensor that counts the interruptions. This in turn is converted into the fuel flow rate.

Of course, the accuracy of the instrument depends on the accuracy of the quantum of fuel in the tank at the start of the flight. This quantum is pilot-fed via buttons on the faceplate, into the Fuel scan 450 Twin.

The JPI manufactured fuel scan 450 Twin displays up to six fuel related measurements. Some of these measurements will be available only if you connect the fuel scan 450 Twin to your GPS. As mentioned previously, the upper display always shows the current fuel flow rates in the selected units. On the right, the pilot may select gallons, litters or pounds. The fuel quantum is displayed in whole units and tenths.  The tenths place is shown as a smaller digit on the right.

Under normal circumstances, the fuel scan 450 will automatically index through all the measurements and display each measurement on the lower side of the display unit. On its left, is a label indicating what the measurement is; while on the right side if the pilot taps the step button, he can manually step through each measurement.

The total fuel used indicates how much fuel has been used by both Digital Gauges since the last refuel. As the flight progresses, these numbers will always become larger. The JPI manufactured fuel scan 450 Twin can also show the fuel used on a long multi-fuel stop flight.

The pilot can reset the fuel used display by holding the auto button for a few seconds until the used display is set to zero hours and minutes. If the JPI manufactured fuel scan 450 Twin is attached to a GPS, then, it can also display fuel required to next Waypoint.

For more information, please visit: https://www.jpinstruments.com/shop/fuel-scan-450-copy/

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What Everyone Must Know About Manifold Pressure Sensor

To the un-initiated, a manifold pressure (MAP), refers to the amount of air in Pounds per square inch entering the aircraft engine i.e. the cylinders. This is a critical parameter for a variety of reasons.

The point of manifold pressure is the throttle valve and the intake manifold of the engine. If we assume that the aircraft is on the tarmac with engines switched off, the MAP would naturally be pressure at the airport. If the airport is at sea level, the MAP pressure should be 29.92. If the altitude were to increase, the atmospheric pressure would decrease.

The moment the pilot starts the aircraft engines (but not touch the throttle), the Manifold Pressure Sensor will decrease because the air suction created by the cylinders would create a low pressure in the manifold.

The rule of thumb is that in a normally aspirated piston engine aircraft, the MAP will be slightly below atmospheric whereas, in a turbocharged aircraft, the presence of the compressor and turbine, enable the engines to supply power at a much higher pressure.

In a turbocharged aircraft, the MAP does not vary with the altitude because the presence of the compressor means the aircraft engine does not have to rely on free-flowing air. The compressor creates a continuous stream of high-pressure air that enables the aircraft to climb quickly.

Of course, the efficiency of the compressor depends on quantum of external air that is available to it. As the aircraft flies higher and higher, the quantum of external air available becomes less and less and the engines will ultimately lose power. However, the loss of power happens more gradually as compared to normally aspirated piston engine aircraft.

The role played by the MAP gauge

When power needs to be reduced, the MAP before the propeller RPM Gauges needs to be reduced first. If the pilot reduces the RPM before the manifold pressure, then there is every possibility that the aircraft engine components will be damaged. This is because air at higher pressure would be entering into the cylinders even though the coarsening of the propeller reduced the engine speed.

To increase the engine power, the props should be set first and then the manifold should be altered. The role played by the manifold gauge is to indicate the health of the fuel-air mixture entering the aircraft engine. It is vital that the fuel-air mixture ratio stays the same and this can be confirmed via the MAP gauge. Any changes will indicate problems with the air intake.

If the air intake decreases, the fuel portion increase making the mixture ‘richer’. But this does not help because lack of oxygen in the combustion process, will reduce the power generated in cylinder. The aircraft would end up burning more fuel but without any increase in the power generated. Now you can understand the role played by MAP gauge in aircraft.

Visit here for more information:- https://www.jpinstruments.com/shop/manifold-pressure-sensor/

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Top 10 Features of EDM 950

EDM 950 – the Aircraft Engine Data Monitoring system, is manufactured by J.P. Instruments; World leader in aircraft cockpit display systems and technologies.

The EDM 950 is amongst the best data acquisition and display system for piston engine aircraft. The EDM 950 comes with a 3-year warranty and, has a TSO quality certification that assures you that you are buying a quality product that meets or exceeds regulations and standards.

As good as having a flight engineer, the EDM 950 provides 30 hours’ worth of backup of all engine data so you’re your maintenance team can download the data and analyse it for aircraft engine health.

From the moment the plane takes off, the EDM 950 works constantly and diligently to monitor the aircraft engine so the pilot can concentrate on just flying the plane. The EDM 950 monitors the aircraft engine parameters roughly 180 times a minute and will warn the pilot the moment any parameter exceeds the pre-programmed limit. The pilot of course can programme the alarm parameters.

Top 10 Features of EDM 950:

1. Hands-free, automatic scanning – EDM 950 will automatically cycle through critical engine and display relevant information. No need to press buttons.

2. Programmable alarm limits – set your alarm limits and receive audio-visual alarm in event of a breach.

3. EDM 950 is paired with latest fast response probes – this provides for faster, and more accurate aircraft engine data.

4. Thirty-hour data accumulation that can be downloaded via cable.

5. Patented LeanFind™ finds the first and last cylinder to peak with true peak detect eliminates false peaks.

6. Super easy and institutive front-panel programming via buttons on faceplate.

7. One of the few EDM’s to provide Exhaust Gas Temperatures (EGTs) to stable 1°F resolution.

8. EDM 950 monitors shock cooling on every cylinder.

9. Pilot selectable index rate.

10. Battery voltage with alarm – many systems will malfunction if aircraft battery fails. Identifying the source of the problem not only saves time but saves the pilot from making errors that might prove to be expensive.

Additional features of EDM 950:

11. Displays below peak and peak leaned temperatures.

12. Battery amps load or charge/discharge display.

13. Customized screen display.

14. DIF low to high EGT with alarm.

15. Easy post-flight data retrieval.

16. Download to Palm™ Computer.

17. Data retrieval software.

18. Oil pressure.

19. Oil and OAT temperature.

20. Fuel level with GPS interface.

21. Solid-state rotor Fuel Flow Transducer.

22. Pilot selectable fuel quantity measure.

23. Low fuel quantity alarm.

24. Total amount of fuel consumed, fuel remaining, and time-to-empty at the current fuel flow rate.

25. Automatically calculates percent horsepower.

26. Stores history of extreme values during previous flight.

27. Includes Hobbs® timer.

For more information, please visit the JPI website page here: https://www.jpinstruments.com/shop/edm-950-2/

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Difference Between EDM-350 and EDM-730

Confused between EDM 350 and EDM 730? Here a comparison between the two to help you select the most suitable EDM for your needs and your aircraft. Both these Engine data managers are manufactured by J.P. Instruments, USA, the EDM 350 is for experimental aircraft only.

Both these Engine data managers provide the aircraft maintenance crew and pilots with real time information pertaining to the engine of the aircraft. Both EDM 350 and EDM 730 monitor the aircraft engine from the moment the ignition is switched on. From that moment on, any anomalies are instantly brought to the pilot’s attention via audio-video alarms.

The EDM 730 is a fantastic piece of aviation technology that offers full-colour high-contrast graphics. It is easily installed (vertical or upside down or horizontal) and is considered to be amongst the most advanced and accurate piston engine-monitoring instrument.

EDM 730

(From $1,839.00 to $3,024.00)

Features: 1. Easy to install. 2. Clear, Full-Colour Graphics 3. Easy-to-read data display 4. Easy to programme 5. Annunciation of exceedances. 6. Fully tested and approved. 7. Displays more information per page. 8. Can be installed in 4 different ways.

Package Form Factor: 1. Requires only 3-1/8" space 2. Just 65mm depth 3. Easy to adjust location. 4. Easily upgradable from 700 series JPI EDM’s. 5. Pilot programmable parameters. 6. Data download via USB port. 7. Horsepower display in percentage. 8. Graphically display of RPM and manifold pressure. 9. Just press button for Rich of peak or lean of peak operation. 10. Computerized fuel-flow system. 11. EDM scanner function. 12. Fuel management can be linked to GPS. 13. Display in portrait or landscape. 14. Meant for turbocharged engines 15. Ideal for 4/6/7/8/9-cylinder engines,

Optional: 1. JPI Carb Temp Option 10-27103 2. JPI Oil Temp Option 10-27100 3. JPI RPM Option 10-01720 4. JPI OAT Option 10-27095 5. JPI Oil Pressure Option 10-04075 6. JPI TIT Option 10-27090 7. JPI Manifold Pressure Sensor 10-04512

More information here: https://www.jpinstruments.com/shop/edm-730-2/

EDM 350

(From $2,879.00 to $4,973.00)

Smaller than a mobile phone, the EDM 350 requires just 3.25 square inches of space on your instrument panel.

Features: 1. CHT 4 or 6 probes 2. EGT 4 or 6 probes 3. Volts 4. LOP/ROP JPI Exclusive Leaning Mode 5. Shock cooling 6. EGT/CHT Harness 7. Power connector 8. EZTrends Software 9. Data recording-600 hrs at every 6 sec (Download via USB) 10. 1 GB memory stick 11. 3-year Warranty

Optional: 1. RPM 2. OIL Pressure 3. MAP 4. OIL Temperature 5. FUEL Pressure 6. OAT 7. FUEL Pressure (for Turbo) 8. CRB 9. TIT 10. Fuel Flow (for Pressurized Carb) 11. Fuel Flow 12. AMPS 13. CDT 14. Fuel Level 15. Frequency 2-Tank (L/R Main) 16. Fuel Level 2-Tank (L/R Main) 17. Remote Alarm Light

More information here: https://www.jpinstruments.com/shop/edm-740-experimental-only-3/