L-1011 Trainer Installation: Main Instrument Cluster - EPR, %RPM N1 and FF Power-Up

L-1011 Trainer - Engine Cluster Power-Up

Switching over to the main instrument panel with the 115V 400Hz system power up for today. Two reasons; a) to run the necessary AC power returns from the CB3 Breaker Panel to the MIP and b) to test out the main instrument cluster and associated breakers. I know I have been talking about these %RPM and EPR instruments for a bit in the past but where is all this %RPM stuff actually located on the engine? Below is an image from the Delta L-1011 Pilot's Reference manual that shows the different compressor spools in the RB.211 engine.

RB.211 Engine from Delta L-1011 Pilot's Reference Manual

EPR, or Exhaust Pressure Ratio, is measured at the engine inlet and outlet and effectively displays the pressure ration between the two of them. This ratio presents a very good picture of the actual thrust output of the engine. 

L-1011 Trainer - EPR and %RPM N1

While the %RPM instruments (N1, N2 and N3) are all somewhat simple tachometer instruments, the EPR will need to be controlled differently. But more about that when we get to the actually connecting the instruments to the computers part of the project.

Below is a short video that shows the 400 cycle power-up and BITE (Built In Self Test) of the Lockheed L-1011 EPR and %RPM N1 instruments. You will notice that the EPR instrument show random values ... this is because they are not connected to a signal source quite yet and the instrument inputs are free floating.

Also powered up the Fuel Flow (FF) instruments, however, without the signal line between the Fuel Used gauges on the Flight Station there is not much to actually demonstrate on these instruments. You see that they have power going to them because they have cleared the flag (the red bar across the digital display on the bottom of the instrument).

L-1011 Trainer: Fuel Flow Power-Up