L-1011 Trainer Installation: 400Hz Power in the Sim

115V AC 400Hz Power Inverter

Today we finally powered up the 115V AC 400Hz inverter for the Lockheed L-1011 trainer. Thanks to Richard Grigg and the engineers from Paul Wiley Electrical who worked late into the evening yesterday to establish the power feed from the main board to the sim room. The device will produce 5000VA on a single phase and will be able to meet all the needs for 400Hz avionics power that we have in the sim and then some more. There was an option to run it as 10KVA device, but we chose not to install it that way. Here are some more details on the unit:

High Power AC 400Hz Military APU 3 Three Phase Inverter 10 KVA output power. Manufactured by Transistor Devices, for transport (Lockheed C130) Auxiliary Power Unit. Input voltage is 208 three phase 50/60 Hz, Output is 200/115 (phase to phase/phase to neutral) VAC at 28 amps/leg, Model numbers are ESU127/A Power supply, and ECU-128/A for the static inverter modules. The inverter is built up from three modules. The thin one on the left is the redundant AC input module that does power factor correction. It then sends 350-450 VDC to the power supply inverter module on the right. Inside the right module a switch mode power supply takes the PFC output voltage and generates +/-200VDC and sends it off to the three phase inverter. The inverter then chops up the DC into three phase 115/200 Wye configuration (with neutral).

We had to move the inverter to the storage room in the museum because the machine is very noisy mainly because of two large air-movers. Below is a short video showing the machine in action.

We now have the 400Hz Power we need for the project in the sim. This marks the beginning of the instrumentation power-up in the trainer.

L-1011 Trainer: 400Hz Power on GEN1

L-1011 Flight Controls: Active Controls Load Distribution (27-51)

In the illustration above the dotted line shows the basic wing lift design load distribution of the L-1011 wing. the solid line shows the redistribution produced by symmetrical upwards deflection of outboard ailerons. Both load distribution lines are for the same structural design wing lift but the redistribution line show how aileron deflection moved the center of pressure inboard thus lowering the wing root bending moments. During cruise, aileron deflection would be minimal.

the Active Control System (ACS) uses outboard ailerons symmetrical deflection to relieve wing loading. Aileron deflection is controlled by accelerometer and sensor signals delivered to the ACS computer and from there on to the aileron servo. The computer provides the following functions:

• Maneuvering Load Control (MLC) by redistributing air loads caused by maneuvering air gusts inward span wise toward the wing root. 
• Elastic Mode Suppression (EMS) - Reduces vibrations along the wing in response to the wings natural bending vibration frequency. 
• High Lift Control (HLC) or wing tip relief when in the high lift, high drag flaps and slats extended configuration. (Both outboard ailerons will be up 8º).