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

L-1011 Trainer Installation: MIP and FE Station Instrument Lighting

L-1011 Trainer: Instrument Lighting Build-Out (FE Station)

Today we continued the build-out of some of the integral instrument lighting on the FE station as well as the main instrument panel. On the FE station we connected the Engine %RPM N2 instruments as well as the Slat Monitor / Slat Position Indicator. All the instruments use 5V power and are driven from either the FE Station Lower Right Light Bus (for the %N2) and the FE Station Upper Right Light Bus (Slat Position).

During the connector installation we discovered that the FE station used for the trainer has a metal plate right behind the Slat Monitor that prevented the connector from mating correctly with the instrument. Therefore, we had to make a panel configuration change and move the Flight Engineer's Annunciator Panel into the position of the Slat Monitor and moved the Slat Monitor down.

L-1011 Trainer: FE Station Instrument Lighting and Door Annunciator

We don't think that this configuration change is going to make a significant difference to the authenticity of the L-1011 cockpit, however, one of the %RPM N2 instruments is still one of the original simulated procedures trainer instruments. Need to replace it with the real flight hardware as soon as I can find one.

L-1011 Trainer: FE Station %N2 Instrument Lighting

Last week we had started powering up the instruments on the pilot's center instrument panel. This is the place where the majority of the engine instruments are located. The instruments are split into two 5V light buses: Captain's Center Instrument Left and Captain's Center Instrument Right. The instruments that you can see illuminated in the picture below all belong to the Center Instrument Right light bus. During the initial build-out session we discovered that we did not have the right connectors for the Engine EPR instruments ... hence, we could not connect them ... we missed three Deutsch 15-S7 connectors. We now have them (those guys are hard to find and expensive) but we finally got them. So now all the instruments belonging to this light bus are connected.

L-1011 Trainer Build-Out: Main Instrument Panel Engine EPR Instrument Lighting

Original Flight Hardware: Rated EPR Mode

The Rated EPR Mode panel is somewhat unusual on the Lockheed L-1011. It allowed the aircraft systems to compute the optimal EPR for a number of different flight phases. The EPR model here allows selection of:

TO .. Take Off
CLB .. Climb
CRZ .. Cruise Flight
GA .. Go Around

The computer EPR value would be display on the center panel right next to the individual EPR gauges.

Original Flight Hardware: Engine Cluster

The Lockheed L-1011 has an awesome engine cluster. It is home to the EPR, N1, EGT, N3 and FF gauges. In the picture above, you actually see instruments from a Boeing 747. I chose the B747 instruments because the will be easier to automate and control with the flight simulator software.





Another deviation from the standard L-1011 engine cluster that you might have noticed by now is that I, for now, substituted N2 gauges for the L-1011 N3 gauge. The reason being that the N3 gauges are pretty difficult to find. However, it does not mean that I will not replace the B747 N2 gauges with N3 gauges that better fit the 3 compressor stages of the L-1011 engines.



As you can see from the picture above, there are quite a few things still missing from the center panel. I don't have any of the standby instrumentation ... which will hopefully come soon.

Panel Location


L-1011 flight station picture used with permission from Sam Chui. Retrieved from airliners.net