Form Drag?
February 22, 2024
Ref Chapter 5 成因: shape and airflow around the airfoil (aircraft) 解決／緩解方法： streamline (as many of the parts as possible) When the air has to separate to move around a moving aircraft and its components, it eventually rejoins
Parasite Drag?
February 22, 2024
Ref Chapter 5 Three sub-type of parasite drag Form Drag Interference Drag Skin Friction Drag not associated with the production of lift Types of Drag?
Air Density , 3H?
February 21, 2024
Ref Chapter 5 Ans: Air Density drop (air becomes less dense) when High altitude (高度) High temperature （溫度） High humidity (濕度)
What’s stalling AoA? What’s CL-max Critical AoA?
February 21, 2024
Ref Chapter 5 Ans: the AoA at which after that the acft will stall! Remember: aircraft (airfoil) always stalls at the same AOA! When the aircraft reaches the maximum AOA, lift begins to diminish rapidly. This is the stalling AOA, known as CL‑MAX critical AOA. Notes: generally, 20° AOA is the critical angle
Relationship between Speed and AoA?
February 21, 2024
Ref Chapter 5 Ans: Speed decrease, AoA need to be increased (and vice versa) Reason is simply, refer to the lift formula, to generate same amount of lift, one factor drop, then another factor must be increased. Lift formula
Lift formula
February 21, 2024
Ref Chapter 5 Ans: Lift = 1/2 * CL * p * V2 * S where CL : coefficient of lift –> related to AoA p : Air Density V: Airspeed S : Wing Surface What’s 4 forces?
What’s AoA – Angle of Attack?
February 20, 2024
Ref Chapter 5 Ans: angle between chord line and the direction of the relative wind
4 forces in steady flight?
February 20, 2024
Ref Chapter 5 Ans: sum of 4 forces is always zero, provided that it is a steady flight! Steady flight? -i.e unaccelerated status! Based on Newton’s 3rd law (every action or force there is an equal, but opposite, reactionor force.) However, amount (magnitude) of 4 forces not exactly same! Weight cancel out by Lift
What’s 4 forces?
February 20, 2024
Ref Chapter 5 Ans: Lift, Drag, Thrust, Weight Thrust— forward force produced by the powerplant/propeller or rotor opposes force of drag. act parallel to longitudinal axis (in general but not must) Drag— rearward, retarding force caused by disruption of airflow by the wing, rotor, fuselage, and other protruding objects drag opposes thrust (in
2024 年初三 ： 有驚無險 要再改進
February 12, 2024
話說今日又再新春行大運 解決了上次深圳灣的問號，修正觀察方式為 Clear right and clear left! 不過今日又要重溫其他野：切線！ 真心，不理想，希望對家不是方仗。是咁的，鏡一定有望，但一出去，架車可能太多人同物件，地板油都吾去, 結果係出曬，但私家車已到屁股，比人bi bi 。 只可下次有進步，總算又一日。
2024 年初一 ：沒有最安全 只有更安全
February 10, 2024
話說今年是第一年在CTB, 亦是第一年大年初一開工（當年九仔都無試過） 新春行大運 深圳灣「無限loop」，不過loop到尾二個轉有點小插曲，就是個水撥識吾到！！！現在有屯廠工程人員，說係就要私回廠整，我覺得ok既 接受到，又真係吾會點影響安全，站長亦指示繼續做生意，化解危機一。 之後小便再上車 shit, 左尾是B3A, 右邊食左架B3, 一係就要倒倒倒 倒車到好後 但風險高，抽右又一定響梗，so delay都要，又算化解危機二。 再黎就出near-miss! 我在出站位停線停 拉埋手制，clear left and then clear right! Near-miss happen then, 按logic 如果停線位前左右兩方都有車行，右邊風險是高過左面（較近車身），問題呢次係第二次在出既期間發現左方有車而我是有點surprise，換句話說我目前觀察方法是要改進！望左 望右 再要補左！ Every day is a new day! 沒有最安全 只有更安全！
