Disk brake (Disc brake)
September 8, 2024
Modern general aircarft (GA) and airliner are also use disc brake Types of disk brake (disc brake) Singel disc Multi-disc Composition of disc? Steel Carbon Modern airliner tends to use carbon multi-disc. Advantage of disc type actuator? more effective at slowing or stopping improve the issue on drum brake (less fading problem) light
Drum brakes
September 8, 2024
Drum brake – not used on modern aircraft Advantage of drum brake? faster response time Weakness of drum brake ? not efficient suffer of brake fade OSH issue – asbestos
民航機的空調系統
August 25, 2024
Function of air condition system improve passenger comfort – air conditioning ventilation – exchange fresh air maintain cabin pressure Component of air conditioning system? B777/A350 for example – Bleed air (from APU/Engine) -> Primary heat exchanger ->air cycle machine (compressor) -> Main heat exchanger -> air cycle machine (Turbine) -> Water separator -> Mixer
Two spools v.s Triple spools
August 4, 2024
References: Difference between Two Spool Engines and Three Spool Engines – FlyFA Aircraft Maintenance Engineering 3-Spool-Engine Concept | aircraftengineering (wordpress.com) What is triple spool design on the RB211? what are the advantages/disadvantages? A 3 spool engine is one that has three sets of compressors before the combustor and three sets of turbines behind it. A
Cooling Methods in Turbine Blades
August 4, 2024
Reference: Cooling Methods in Turbine Blades | Turbomachinery blog (softinway.com) thermal barrier coating on the turbine blade (Blade Passive Protection) internal cooling – maintains the blade metal temperature below the outside gas temperature by heat transfer to internal cooling air – include convection cooling and impingement cooling, where cooling air runs through channels within the
[GA piston engine] What’s full throttle height?
August 3, 2024
Full throttle height – Depending on the power setting, as an aircraft climbs (fitted with a fixed-pitch propeller), a height is reached eventually where the throttle will be fully open to maintain that power setting. Important concept: An aicraft can have various power setting! Each power setting has a full-throttle height! Read more
[GA Piston Engine] Effect of Increasing Height on Power Output
August 3, 2024
(On a ‘standard’ day) Aicraft climbs / fly high –> output of the engine decreases for two reasons: decrease in atmospheric pressure – reduces the manifold pressure and thus the flow of air into the cylinders (a similar effect to closing the throttle) – can be compensated for by progressively opening the throttle decrease in
Too lean, Too rich, CCM, Best power, Best economy
August 3, 2024
Notes: The carburettor measures the weight of air passing through the induction manifold and uses this measurement to regulate the amount of fuel discharged into the air stream (according to a predetermined schedule). What’s rich, lean and CCM? Rich: 1:8 Chemically Correct fuel/air Mixture (CCM): 1:15 Lean: 1:20 In theory, the ‘correct’ quantity
What’s Feathering? (Propeller)
July 21, 2024
Ref untitled (cast-safety.org) 原文: “On a variable pitch propeller, the drag can be minimized by rotating the blades until they are edgewise to the flight direction. This is called feathering the propeller.” Why we need “feathering the propeller”? / When we need to “feathering the proeller”? When an engine is shutdown in flight, an
Why turbofan engine needs High bypass ratio? 點解要high bypass ratio?
June 1, 2024
Force = mass x acceleration [Ref Turbofan Engine | SKYbrary Aviation Safety] High bypass engines usually have a single stage fan which generates a high volume but relatively low speed air stream. The fan airflow, referred to as the cold air stream, is accelerated by the fan and passes through the engine remaining outside of
Why aircraft fly SO HIGH? 點解民航機要飛高D?
June 1, 2024
To answer this question, there are various approach. Weather Speed (Lift formular – air den v.s TAS) Efficiency of the engine Read More – Why Are Jet Engines More Efficient at Higher Altitudes? – HighSkyFlying
Carbon Fiber Composite (CFC) , Ceramic Matrix Composite (CMC)
May 27, 2024
CMC More about CMC: Behind the GE9X engine’s advanced technologies | Paid content | Flight Global CFC
