Instead of a big, round and chunky piece of dial that display one single piece of data in an analog format, a slim-line instrument, displays the same data an intelligent, backlighted LCD digital format and its physical footprint is comparatively tiny.
I’ve been flying my Piper Seneca V ferrying scientists and equipment to all parts of north Canada. This is a 2004 build and last year, I decided to upgrade its avionics. I however did not have the budget to do it all in one go, so; I decided to do it piece-meal.
I would plan for it and as and when I accumulated enough to buy a particular Slimline Instruments manufactured by J.P. I, I would go ahead and do the purchase.
To begin with, I bought the J.P.I. rack frame (only the frame). It has 8 slots – one each for OAT, Volt Meter, Oil Temperature, RPM Tachometer, Manifold Pressure, Fuel Pressure, Oil Pressure and TIT Probe.
Prior to that had got rid of some junk I had installed and also replaced the entire dash so passengers did not see a dashboard full of large gaping holes. After fitting the J.P.I. multi-rack frame, I made only one hole – to fit the OAT gauge. Naturally, I had to also buy the OAT sensors for the gauge. These are super-fast response sensors. The fitting and connecting to the OAT to its sensors was simple and quick.
Overtime, every few months or so, I added a new gauge or two. It took me almost the entire year before all the slots of the rack were filled with the latest slim line instruments.
Now I don’t have to watch the gauges like a hawk. Each Slim Line Pressure Gauge has a red line LED so any reading that is over or under is instantly brought to my notice. For example, the volt amp gauge has a discharge alarm and 0.1 Volt or amp resolution. The Oil and Fuel Pressure gauges have under pressure alarms as well as resolution to 1.0 psi. The Oil, TIT and EGT TEMPERATURE gauges all have high limit alarms and resolution to one degree.
Once the rack was filled, it saved panel space and also provided me with the accurate information I needed to keep flying safely. Moreover, these slimline instruments are all backlit so I no longer had to strain to see any individual gauge.
Another major difference is that these slim-line gauges are “digital” meaning, they display the engine data in tall, red numbers. No more quivering needle on a dial. Numbers make it more accurate. So instead of displaying one-third on a dial for fuel in the tank, I could now just read off the numbers to know how much fuel was used.
Each of these slim line instruments was connected to the aircraft engine via fast response sensors and wires. The wires transmit data in electrical pulses that is interpreted by the smart electronics circuits inside the slimline gauges.
Eventually, (in another few years), I plan to replace the rack with an EDM – so I have one small display unit instead of the rack. But until then, the rack allows me to get the latest tech minus the fancy price of the EDM.
For options on modern slim line gauges, please visit: https://www.jpinstruments.com/shop/slim-line-experimentalhomebuilt/