ATA 78 Exhaust - PDF - Bombardier DHC 8-400 (PWC PW150)

BOMBARDIER DHC 8-400 (PWC PW150) ATA 78 - EXHAUST TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1/B2 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 8 BOMBARDIER DHC 8-400 (PWC PW150) EXHAUST The top rear structure of the nacelle is also part of the shroud assembly. GENERAL...

BOMBARDIER DHC 8-400 (PWC PW150) ATA 78 - EXHAUST TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1/B2 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 8 BOMBARDIER DHC 8-400 (PWC PW150) EXHAUST The top rear structure of the nacelle is also part of the shroud assembly. GENERAL DESCRIPTION Heat insulation blankets cover the top outer surface of the forward shroud assembly. The exhaust system contains the hot engine exhaust gas as it moves rearward through the nacelle. The exhaust system is cooled by an eductor system. The eductor draws ambient air flow between the jet pipe and the shroud. The air inlet for the eductor system is an air inlet scoop on the nacelle centre side panel. The exhaust system has two assemblies: The exhaust system has these components: • • The jet pipe assembly The shroud assembly The jet pipe assembly has three parts: • • • The exhaust nozzle The forward jet pipe The aft jet pipe The jet pipe assembly contains the engine exhaust gas as it moves rearward from the engine. • • • • • • • • • • • Exhaust Nozzle Exhaust Nozzle Shroud Forward Jet Pipe Forward Insulation Blankets Forward Shroud Aft Jet Pipe Aft Insulation Blankets Mid Shroud Aft Shroud Trunnion Bearings Aft Exhaust Outlet The routing of the jet pipe is under the wing box and over the main landing gear stowage bay. The exhaust gas goes through the jet pipe and into the atmosphere at the top rear surface of the nacelle. Heat insulation blankets cover the outer surface of the jet pipe. The primary ejector is located between the exhaust nozzle and its shroud. It gives cooling airflow through the engine fire zone (Zone 1). This flow joins with the engine exhaust gas to exit through the jet pipe. The secondary ejector is located at the aft end of the jet pipe. It gives cooling airflow through the area between the main and aft firewalls and between the jet pipe and shroud (Zone 4). The shroud assembly houses the jet pipe assembly along its full length. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 78 - EXHAUST Issue 6 - January 2023 Page 2 of 8 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE EXHAUST - EXHAUST ASSEMBLY TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 78 - EXHAUST Issue 6 - January 2023 Page 3 of 8 BOMBARDIER DHC 8-400 (PWC PW150) EXHAUST The inner sheet is 0.004 in (0.1 mm) thick and the outer sheet is 0.006 in (0.15 mm) thick. COMPONENT LOCATION AND DESCRIPTION When the insulation blankets are assembled, the Kaowool is compressed to a thickness of approximately 0.375 in (9.53 mm). EXHAUST NOZZLE Lockwire holds each pair of insulation blankets in position. The exhaust nozzle is attached to the rear of the engine by a V-band coupling. EXHAUST NOZZLE SHROUD The exhaust nozzle shroud surrounds the exhaust nozzle and with the nozzle, forms the primary ejector. The exhaust nozzle shroud is conical approximately 25 in (635 mm) at the forward end to 17.8 in (452 mm) at the aft end. A flange, welded to the rear of the exhaust nozzle shroud, attaches to the engine firewall. FORWARD JET PIPE The forward jet pipe is installed in the centre of the nacelle, under the wing box. The forward jet pipe is made from three pieces of Iconel 625 welded together. The forward piece of pipe is conical from 17.96 to 15.85 in (456.2 to 402.9 mm). The other pieces have an outer diameter of 15.85 in (402.9 mm). FORWARD SHROUD The forward shroud surrounds the forward jet pipe. The shroud is also a firewall for the adjacent area. The forward shroud is made from two pieces of titanium welded together. The forward piece of the shroud is conical outer diameter from 19.61 to 18.05 in (498 to 459 mm). The other piece has an outer diameter of 18.0 in (457 mm). A P-seal and flange seal holds the front of the forward shroud in position against the engine firewall. The forward shroud is attached to the mounting pin assembly on each side of the forward jet pipe. A seal on the rear of the forward shroud engages with the mid shroud. The top front piece of the forward shroud has two insulation blankets on it. The blankets lower the rate of heat release from the jet pipe into the area of the wing and front spar. Lockwire attaches the insulation blankets to lugs on the forward shroud. A P-seal and flange seal holds the front of the forward jet pipe in position against the engine firewall. AFT JET PIPE A mounting pin assembly on each side of the forward jet pipe attaches to the nacelle structure. The rear of the forward jet pipe connects with the aft jet pipe. The aft jet pipe is installed in the aft of the nacelle, above the MLG wheel bay. The aft jet pipe has an outer diameter of 15.85 in (403 mm). FORWARD INSULATION BLANKETS An E-seal and V-band coupling connects the aft jet pipe to the forward jet pipe. A mounting pin assembly on each side of the aft jet pipe attaches it to the nacelle structure. Each mounting pin assembly has a trunnion bearing, which moves longitudinally in the slot of a bracket. Eight insulation blankets are installed around the forward jet pipe. The function of the insulation blankets is to lower the rate of heat release from the jet pipe. The blankets are made from 0.5 in (12.7 mm) thick Kaowool, between two thin sheets of stainless steel. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY The V-band coupling and trunnion bearings let the jet pipe expand and contract with temperature. ATA 78 - EXHAUST Issue 6 - January 2023 Page 4 of 8 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE EXHAUST - EXHAUST ASSEMBLY DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 78 - EXHAUST Issue 6 - January 2023 Page 5 of 8 BOMBARDIER DHC 8-400 (PWC PW150) EXHAUST A seal on the front of the aft shroud engages with the mid shroud. A V-band coupling attaches the rear of the aft shroud to the aft exhaust outlet. A tie rod assembly on each side of the nacelle structure attaches with the aft shroud. COMPONENT LOCATION AND DESCRIPTION CONTINUED TRUNNION BEARINGS AFT INSULATION BLANKETS Six insulation blankets are installed around the aft jet pipe. The insulation blankets lower the rate of heat release from the jet pipe. The blankets are made from 0.5 in (12.7 mm) thick Kaowool, between two thin sheets of stainless steel. The inner sheet is 0.004 in (0.1 mm) thick and the outer sheet is 0.006 in (0.15 mm) thick. When the insulation blankets are assembled, the Kaowool is compressed to a thickness of approximately 0.375 in (9.53 mm). Lockwire holds each pair of insulation blankets in position. Each mounting pin assembly on the aft jet pipe has a trunnion bearing. The trunnion bearing moves longitudinally in the slot of a bracket on the nacelle structure. The trunnion bearings let the jet pipe expand and contract with temperature. AFT EXHAUST OUTLET The aft exhaust outlet is a titanium ejector shroud with a titanium extension shroud around it. Both have an extended cut-out at the top rear position to let the engine exhaust gas exit to outside air. A V-band coupling attaches the ejector shroud to the aft shroud. The rear end of the extension shroud is attached to the nacelle structure. MID SHROUD The mid shroud is installed around the rear of the forward jet pipe and the front of the aft jet pipe. The mid shroud is also a firewall for the adjacent area. The mid shroud has two pieces of titanium, both of which have an outer diameter of 19.55 in (497 mm). A V-band coupling connects both pieces of the mid shroud together. The front and rear of the mid shroud engages with a seal on the forward and aft shroud. A tie rod assembly on each side of the nacelle structure attaches to the mid shroud. AFT SHROUD The aft shroud is installed around the aft jet pipe. This shroud is also a firewall for the adjacent area. The aft shroud has two pieces of titanium, both of which have an outer diameter of 18.0 in (457 mm). A V-band coupling connects both pieces of the aft shroud together. The aft shroud is attached to the mounting pin assembly on each side of the aft jet pipe. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 78 - EXHAUST Issue 6 - January 2023 Page 6 of 8 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE EXHAUST - EXHAUST ASSEMBLY DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 78 - EXHAUST Issue 6 - January 2023 Page 7 of 8 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 78 - EXHAUST Issue 6 - January 2023 Page 8 of 8