Presentation on theme: "Rev A Sept. 18, 2007 22-3 Fuel Control S64F Model Helicopter."— Presentation transcript:
Rev A Sept. 18, 2007 22-3 Fuel Control S64F Model Helicopter
Rev A Sept. 18, 2007 22-4 Engine Fuel Control The engine fuel control has three inputs from the cockpit. N1 from the N1 lever Collective Bias from the mixing unit (COLLECTIVE) N2 Beeper trim ( Flat Pitch Topping) These inputs are adjusted and rigged at time of fuel control installation.
Rev A Sept. 18, 2007 22-5 Engine Control Location
Rev A Sept. 18, 2007 22-6 Power Control Adjustments The engine controls are to be rigged after an engine, fuel control or any part of the engine control system is replaced. After proper rigging of controls is done, the engine can be ground run and part power trim performed. Before Starting the Engine perform a Fuel Shutoff Check Ground idle speed check – refer to graph for proper range, idle usually at 43-44%. Adjust at idle TRIM screw. 5 clicks of screw is about 1% N1. Check Bleed Band Closing Range Flat Pitch Topping Check is done with N1 at full open and N2 at 100%. Actuate beeper switch to minimum, N2 should be 94%-97%. Actuate beeper switch to maximum, N2 should be 103%-107%. Adjustments are made on the Beeper trim motor.
Rev A Sept. 18, 2007 22-7 Power Control Adjustments The part power trim is done with a calibrated stop specific for each fuel control, and the Bias guns disconnected. The engine is trimmed at a specific EPR target. The adjustments to the MIL screw is done to achieve the specific EPR. Note: When adjusting the EPR down the MIL screw is turned Clockwise. In the down adjustment only turn 10 clicks past target and then back up to target.
Rev A Sept. 18, 2007 22-8 Part Power Trim To get the proper number of clicks, some math is required. EPR Below Target 1. Subtract recorded EPR from Target EPR 2. Divide Results by 0.007 Target EPR (1.54) – Recorded EPR ( 1.47) = 0.07 0.07 / 0.007 = 10 10 is the number of clicks to increase the MIL screw Counter ClockWise
Rev A Sept. 18, 2007 22-9 Part Power Trim EPR Above Target 1. Subtract target EPR from recorded EPR 2. Divide Results by 0.007 Recorded EPR ( 1.70) - Target EPR (1.54) = 0.16 0.16/ 0.007 = 23 CW 23 clicks + CW 10 clicks + CCW 10 Clicks When adjusting in the CW direction, always go 10 clicks past and come back 10 click CCW to the correct adjustment. This will take any slop out of the internal linkage.
Rev A Sept. 18, 2007 22-10 Part Power Trim Once the part power trim is done and the target EPR is met, reconnect the bias gun cables and adjust the bias to nominal (3/4 turn off of the stop) The process of doing a part power trim is done to ensure that at full power the engine is developing maximum power (military)
Rev A Sept. 18, 2007 22-11 MIL IDLE SLOT STOP PART POWER TRIM STOP MILITARY MARK
Rev A Sept. 18, 2007 22-12 1.Description of fuel system on Engine. 2.Fuel Pump a. De-Ice heater b. Fuel Oil cooler c. P & D d. Fuel Manifold e. Fuel Nozzles f. Fuel Control g. Green Tags (All information) h. Fuel lubrication (importance of it) 2. Trouble Shooting a. Fuel pump b. Pressure and Dump valve c. Fuel control 3. Shop Visit a. Fuel Nozzle test b. FCU (test bench) 4. Overview a. Test Engine Fuel System Outline
Rev A Sept. 18, 2007 22-13 Engine Fuel Pump Schematic Fuel Pump Pt3 From Engine Butterfly Valve (Shown Open) Fuel De-Icing Heater Pt3Air Dumped Overboard Orifice Plate Fuel De-Icer Bypass Valve Fuel In From Tank
Rev A Sept. 18, 2007 22-17 Fuel Control Internal
Rev A Sept. 18, 2007 22-18 Engine Control Location
Rev A Sept. 18, 2007 22-19 Differential Pressure Switch: The differential pressure switch closes as Differential pressure across the fuel filter increases past 4-5psid (28-34 kPa). The psi. differential indicates contamination and possible ice in the filter. Differential Pressure Indication Light: The differential pressure indication lights are located on the caution advisory panel. The lights are labeled “#1 ENG FUEL BY-PASS” and “#2 ENG FUEL BY-PASS”. Component Description
Rev A Sept. 18, 2007 22-20 Fuel Differential Switch
Rev A Sept. 18, 2007 22-21 Fuel System Schematic