For technicians about to install the JPI EDM 740 in an aircraft, this article is for you. It covers all the general points to installing the JPI EDM 740. To start with, only FAA certified aircraft mechanic should attempt to install the EDM 740 in aircraft. General Installation Instructions: 1.The EDM 740 (as do all EDM’s), are equipped with a delicate LCD display module. To prevent any damage to it, it is imperative that the mounting screws not penetrate the instrument by more than 0.12 inches. Ideally, use the steel template supplied with the installation kit. 2.The aircraft on which the EDM 740 is to be installed, should have necessary FAA approvals. 3.Special attention and care should be taken while crimping the wires. It is recommended that the technician fold back the wire double before crimping terminals. 4.Avoid aluminium fittings for planes equipped with FXT-201 or FXT-231 fuel flow transducer. 5.Before you begin, note down the K-factor (see side of the fuel flow transducer) 6.Map the holes and make sure there is nothing behind the panel that is likely to get damaged during the drilling process. 7.Provide service loops for all wires near the panel as well as near the engine (including Thermocouple wire) Service loops near the aircraft engine are required probes can be swapped for troubleshooting purposes. 8.Tie/keep wires away from heat sources. 9.Where soldering is required, use zinc chloride flux such as Nokorode brand. 10.Polarity of wires is vital and EDM 740 must be grounded at the engine, not at the avionics ground. 11.If the aircraft has a spark plug gasket probe, the CHT reading on that cylinder will be somewhat higher than cylinders with bayonet probes. Optionally, you could opt for an adapter probe (bayonet or screw-in) so that the factory CHT Probes and the JPI probe to be placed in the same bayonet location. 12.Wires from the probes and sensors should be routed through the firewall using fireproof rubber grommets and flame retarding silicone. Rather than drilling new holes, make use of existing holes. 13.Keep sufficient slack (but ensure the wires do not touch the engine surface). Secure the probe leads roughly 8 to 12 from the probe. 14.The JPI RPM Sensor kit comes with a 3-pin connector – please, only use this connector. 15.Make sure the wiring does not obstruct the controls or anything else under the panel. 16.Ensure the probe wires are not tied in with alternator, ignition or twin-engine cabin heater ignition wires as there is possibility of interference with temperature readings. 17.While power and ground wires are normal copper, the temperature probe wiring harness is made of Chromel-Alumel alloy wire (yellow). Do not substitute it or extend with normal copper wire – these are not compatible. Leads may be spliced only with additional Chromel-Alumel wire using copper butt splices. 18.On completion of the installation process, all wires should be secured using ties and carefully checked for rubbing, interference or chaffing with flight control cables or other moving parts. For more information on J.P. Instrument’s EDM-740, please visit: https://www.jpinstruments.com/shop/edm-740-experimental-only-3/
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Combustion whether in aircraft or cars or anything that has an engine, not only relies on accurate mixture of air with fuel before ignition, it also requires the air and fuel to be at optimal temperature - this ensures instant and clean combustion. Aircraft typically fly at altitudes where the air is very cold. This cold, dense and often freezing air impedes combustion and may even need to be pre-heated before mixing with fuel. So how does the aircraft know if the air is at the correct temperature or not? This is where the Intake Air Temperature (IAT) sensor comes into play. An automobile engineer’s solution to the cold air problem would be to increase the fuel in the fuel-air mixture. Cold air being dense, the extra fuel in the mixture corrects the fuel-to-air ratio and ensures proper combustion. The increased fuel consumption is not a problem as a land-based vehicle can stop at the nearest fuel station and fill up – this however, is not an option for aircrafts. The aircraft therefore, is designed to pre-heat cold air so it is ‘combustion-friendly’. Whether to heat or not, is triggered by the onboard engine controller that is fed with data from the IAT probe. The IAT probe directly feeds air temp. data into the air temp indicator / onboard controller. Based on the air temp data received from the IAT probe, the engine controller dynamically alters the air-to-fuel ratio by changing the timing of the injector pulses. When installing the Intake Air Temperature (IAT) probe, only the tip of the probe is exposed to external air entering the aircraft engine. The IAT probe itself is mounted just inside the air intake manifold of the Aircraft Engine Monitor. How the IAT probe works: Technically, the IAT probe is a thermistor. This means its electrical resistance is directly proportional to the changes in the air temperature i.e. the output voltage from the IAT probe varies depending on the air temperature. The output voltage for your aircraft’s IAT probe is usually mentioned in your aircraft service manual (or the leaflet that came with the IAT probe -if you’ve purchased a new one). On ground, the pilot needs to eyeball the IAT probe to ensure it is not coated with sooth, oil or bird feathers as these could cause the IAT probe to malfunction. A malfunctioning Air Temperature Probe will in turn the on-board engine computer miscalculating the air-to-fuel mixture. More information on IAT probes for aircraft can be found here: https://www.jpinstruments.com/product-category/probes-sensors/ Even the Wright brothers plane had a couple of dials near their seat in the plane. If nothing else, they at least had to know how much fuel they had in the fuel tanks. Without the presence of a working dial or two, as a pilot, you wouldn’t have the foggiest idea on what was happening in the engine compartment – let alone know where they were going. Today, thanks to aircraft engine monitors, the pilot is often aware of a major life-threatening aircraft engine malfunction before it even happens. Are the cylinders over-heating? Is there a fuel line block? Is the magneto malfunctioning causing the voltage to fluctuate or drop? And so on and so forth. The aircraft engine monitors are similar in function to the monitors we see in a hospital – monitors that monitor the vital life signs of a patient. A single glance at the monitors and the doctor becomes fully aware of the patient’s life status. Ditto the aircraft pilot. Aircraft engine monitors and gauges supply the pilot(s) with visual data regarding the health of the aircraft engine and its current performance in real-time. Combine these with GPS and your pilots not only know the state of the engine, they also know their exact current geographic location. Any engine has certain manufacture determined safety parameters within which it has to operate. Any deviation is a malfunction that could lead to a catastrophic failure. These days, thanks to IC technology and AI software, aircraft engine monitors not only provide data, they actually watch over the aircraft engine and provide a visual or audio-visual warning to the pilots if and when any engine parameter is not within operating limits. To further improve the functionality of the aircraft engine monitors, manufacturers such as J.P. Instruments amongst others, have gone a step ahead and inserted memory cards within the engine monitors. The memory card enables the maintenance crews to download engine data via convenient USB / serial ports. This data can not only be analysed by the maintenance crew, over time, they help keep a record of the engine performance. Every part of the aircraft engine is vital which explains why some of the engine monitors and engine Digital Gauges include engine pressure and temperature gauges, RPM counter, fuel flow and fuel level gauges (one set per engine), air intake temperature and so forth. Every part of the aircraft engine is monitored which also explains why the aircraft cockpit used to have so many dials and knobs crammed into every nook and corner of the cockpit. Today however, thanks to Engine Monitor the aircraft cockpit looks more like a gamming room with just a few futuristic looking LCD/LED screens and a dozen dials. These futuristic looking screens are called ‘EDMs’ - Engine Data Managers and they have replaced most of the monitors and Airplane Gauges of earlier times. JPI is a leading manufacturer of after-market gauges, EDM and sensors used in aircraft: https://www.jpinstruments.com Either you are planning to upgrade from an older EDM to EDM 730 or are planning on replacing some analog dials with the EDM 730 but in either case, your choice of EDM 730 could not have been better. The Aircraft Engine Data Management 730 is an awesome piece of technology that offers clear, full-colour high-contrast graphics. It is easily installed (vertical or horizontal) and is considered as the most advanced and accurate piston engine-monitoring and advisory instrument on the market. It has been TSO’d for quality. The Aircraft Engine Data Management 730 is one of the easiest to programme and all programming is done from the front panel. Here is an abridged list of its features and specifications: 1. Easy to install. 2. Clear, Full-Colour Graphics. 3. Easy to programme. 4. Annunciation of exceedances. 5. Easy-to-read data display. 6. Fully tested and approved. 7. Displays more information per page. Package Form Factor: 1. Four mounting options. 2. Requires only 3-1/8" space. 3. Just 65mm depth. 4. Easy to adjust location. 5. Data download via USB port. 6. Easily upgradable from 700 series JPI EDM’s. 7. Pilot programmable parameters. 8. Just press button for Rich of peak or lean of peak operation. 9. Horsepower display in percentage. 10. Graphically display of RPM and manifold pressure. 11. Fuel management can be linked to GPS. 12. Computerized fuel-flow system. 13. EDM 730 scanner function. 14. Ideal for 4/6/7/8/9-cylinder engines. 15. Display in portrait or landscape. 16. Turbocharged engines. Optional: 1. JPI Carb Temp Option 10-27103 2. JPI Oil Temp Option 10-27100 3. JPI RPM Sensor Option 10-01720 4. JPI Oil Pressure Option 10-04075 5. JPI Manifold Pressure 10-04512 6. JPI OAT Option 10-27095 7. JPI TIT Option 10-27090 More information here: https://www.jpinstruments.com/shop/edm-730-2/ |
AuthorJ.P.Instruments was founded in 1986 in Huntington Beach, California, USA. Its founder, Joseph Polizzotto, is now the current CEO. Archives
May 2019
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