Category: ATPL Knowledge

Bank angle and Load factor relationship

Read More

What’s load factor (LF)?

The ratio between the lift produced by the wings (i.e., apparent weight) and the actual weight of the aeroplane is called the load factor (LF).   Note: Load factors can be expressed in terms of the acceleration (on a body) due to the earth’s gravity (g) Read More

How to reduce induced drag?

Reference: Flying better: Winglets make aircraft quieter and more (facc.com) Reducing_Induced_Drag (centennialofflight.net)   How to reduce induced drag?   Winglet High aspect ratio wing Long span/short chord wing (high aspect ratio), the wing tip vortices are smaller because of the reduced airflow from the lower to the upper surface of the wing and therefore the Read More

Center of Pressure (CoP)

  Center of pressure (CoP) is the point on the chord line of an aerofoil through which the total reaction acts on The angle of attack is increased, the centre of pressure on an cambered aerofoil moves progressively forward (towards the leading edge) – AoA increase, CoP moves forward! Read More

Total Reaction = Lift + Drag

  Total reaction (TR) can be describe as the sum of lift and drag. Total reaction act on center of pressure (CoP)   Read More

What’s Feathering? (Propeller)

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 Read More

Propeller – Fine (Feathering) , Coarse (Windmilling)

  What’s Feathering? (Propeller)   Read More

到底HKO 幾耐UPDATE 一次METAR/TAF?

Ref AIP VHHH Part 1 GEN – GEN 3.5 METEOROLOGICAL SERVICES 3  Meteorological Observations and Reports 3.1 Weather Observers are on duty H24 at the AMO and I-AMO to make routine meteorological observations and to issue reports at half-hourly intervals. Reports of routine observations are issued as local routine report for dissemination at the aerodrome and as METAR for dissemination Read More

一次搞懂香港,澳洲, 美國的Cloud base / Cloud ceiling

話說上堂老師教Cloud Base 同 Cloud Ceiling 既分別 METAR / TAF 報既cloud 都係AGL? 同埋提我地一個好重要既Concept: METAR 同 TAF 報既Cloud information 都是AGL! 到底邊到有講…都真係搵左幾耐!   Hong Kong AIP HONG KONG – GEN 1.7 DIFFERENCES FROM ICAO STANDARDS, RECOMMENDED PRACTICES AND PROCEDURES “Cloud ceiling” in relation to an aerodrome means the vertical distance from the elevation of the aerodrome to the Read More

What is global circulation?

Knowledge from this clip: Global Circullation is one of the drivers for climate and phenomenon: Jet Steam Previling wind Engergy (heat) from sun reachs the earth by radiation Earth itself is an irregularly shaped ellipsoid Energy is much more concentrated near the equator Earth is tilted, sun light cannot reach the poles at all time In Read More

當颱風遇上季候風

Read More

Monsoon 合集: 一次了解多個地方既季候風

Monsoon: a seasonal prevailing wind in the region. Monsoons are large-scale wind systems caused by differences in the temperatures of land and sea over the seasons. HONG KONG 香港 Also Reference:Strong Monsoon Signal|Hong Kong Observatory(HKO)|Details of Warnings Key knowledge from this clip: Winter in Hong Kong : North to East (North-East) monsoon Summer in Hong Read More

What’s El Niño and La Niña? 厄爾尼諾? 拉尼娜? 聖嬰?

生字 learn from these videos: Extreme natural events Bush fire 山火 Heat waves Drought 乾旱 Floods Cyclones coral bleaching (珊瑚白化)   Reference:El Niño Southern Oscillation (ENSO)   Swing (shifts/ changes) between phases El Nino Neutral La Nina Notes: can divided into more phases, but in general, there are three “status”. Knowledge from this clip: Effect Read More

Four Seasons at … (… 的一年四季) : 您除左去飛…都可以了解下人地既地方嫁麻~

Hong Kong Definition of seasons |Hong Kong Observatory(HKO)|Educational Resources Background 香港位於亞熱帶,一年中亦有不同的氣候特徵,例如一、二月較冷,七、八月則較熱,六至八月較為多雨,而十一、十二月則較乾燥及雲量較少。目前,香港天文台採用「氣象季節」來劃分四季,並提供各季節的氣候資料分析和氣候服務,其範圍包括季節預測、趨勢分析、排名計算、氣候變化研究等。「氣象季節」是將一年分為四個長度大致相等的時段(即每三個月為一段),以北半球為例,最溫暖和最冷的時段分別指定為夏季(六月、七月和八月)和冬季(十二月、一月和二月),介乎於夏季和冬季之間就是秋季(九月、十月和十一月)和春季(三月、四月和五月)。這個定義亦與香港30年(1981-2010)月平均氣溫(圖1)所描繪的年度溫度週期大致吻合,即六月、七月和八月通常是最熱的三個月,而十二月、一月和二月是一年中最冷的三個月。 使用「氣象季節」的優點是每年的季節長度和季節開始時間大致不變,在研究分析、結果比較和服務產品發展上較為簡單方便。而公眾和特別用戶亦可以容易理解和使用相關數據和產品。世界上主要的氣候中心,如北京氣候中心、歐洲中期天氣預報中心、日本氣象廳、美國國家海洋和大氣管理局等也基於「氣象季節」來進行氣候分析和提供一些氣候服務。 除了「氣象季節」外,一些研究人員和氣象機構亦會以不同氣象要素和指標來劃分四季及其他特定季節,例如以滑動平均氣溫來計算每年進入四個季節的日期、以降雨量來計算雨季的開始日期、以季候風水文循環的特徵來判斷進入季風季節的日期等。這些以觀測數據為基礎的季節劃分法一般較複雜,較多用於氣候研究之上。而計算出來的季節開始和結束日期每年都有明顯變化,同一套劃分法在不同地區亦不一定完全適用。 Hong Kong’s climate is sub-tropical with different climatic characteristics throughout the year. For example, January and February are colder, July and August are hotter, June to August are rainier, while November and December are drier and less cloudy. Currently, the Hong Kong Read More

Why Inline 4 or straight 6 Engines Always SUCKED for Airplanes

Read More

What’s Coanda Effect? [How aircraft wings generate lift?]

讀左Aviation 咁耐, 大家多數只係識用 Bernoulli principle 去解釋…固然無錯… 但不得不說…再學術少少, 吾好吾識 Coandă effect The Coandă effect (/ˈkwɑːndə/ or /ˈkwæ-/) is the tendency of a fluid jet to stay attached to a convex surface.[1] Merriam-Webster describes it as “the tendency of a jet of fluid emerging from an orifice to follow an adjacent flat or curved surface and to entrain fluid from the surroundings so that a region Read More

How airbrone weather radars work?

Read More

Why is the RUDDER SPLIT? (Hydraulic topic)

Read More

Why does the RUDDER point to the right? (大機的迷思 – Hydraulic stuff)

Read More

Trimmable Horizontal Stabilizer (THS)

Read More

1 2 3 7
wpChatIcon