Tze Shan 0 Report post Posted August 26, 2006 yo Syaz, we are from the same boat man..i still remember how i excited i got when they started the Bernoulli's principle in form 5.. hahhaha u went to the interview too? Share this post Link to post Share on other sites
Brennan Raj 0 Report post Posted August 26, 2006 u went to the interview too? no bro...i only went for the physcomotor test..now waiting for MISPA..i meant same boat as in i also just finished form 5.. Share this post Link to post Share on other sites
Tze Shan 0 Report post Posted August 26, 2006 how i wish i can be like you, they never reply my application. cheers.. Share this post Link to post Share on other sites
Min Chun 0 Report post Posted August 26, 2006 how i wish i can be like you, they never reply my application. cheers.. Hey no worries bro.. Like what had a 744Capt told Edwin.. It's just a matter of time Share this post Link to post Share on other sites
Pieter C. 5 Report post Posted August 26, 2006 No more airflow in high speed perhaps? A/c reducing the speed(airflow over the wings->slower? ) , lift reduced, hence altitue decreased? high speeds ??? ... just imagine to keep altitude There wont be any more lift when the wing has stalled, and this happens approximately around 15 degree angle of attack( varies from wing to wing according to the NACA shape of airfoil). this happens because there is no airflow over the top section of the airfoil and hence no lift is produced. Again................why does this happen (the wing stalls) ??? You can increase airflow by extending slats and flaps, though... Share this post Link to post Share on other sites
Min Chun 0 Report post Posted August 26, 2006 (edited) high speeds ??? ... just imagine to keep altitude Again................why does this happen (the wing stalls) ??? You can increase airflow by extending slats and flaps, though... Keep altitude..maintain the thrust? haha I surrender already la Uncle Pieter.. Edited August 26, 2006 by Min Chun Share this post Link to post Share on other sites
Tony 1 Report post Posted August 27, 2006 high speeds ??? ... just imagine to keep altitude Again................why does this happen (the wing stalls) ??? You can increase airflow by extending slats and flaps, though... I'm no expert, but as far as I've learnt (and actually remember), the wing doesn't stall due to lack of high speed. Could be right, but not accurate enough. Aircraft has minimum and maximum operating speeds. Too slow, weight > lift (possibly produced) and the a/c starts to lose altitude. Too fast, wings get ripped off (probably not literally, but just a general idea that the a/c structure couldn't withstand the pressure). And as Khushwant mentioned, there's a range of angles for each types of wings for lift production. Outside the range, you'd be struggling and very well be stalling the wing. Uncle Pieter's suggestion: Extend slats and flaps. That could help, but just a bit. Note that extending slaps and flaps also introduces more drag (besides hoping to obtain more lift) into the situation. Which is generally why you're asked to point the nose down to recover from a stall - to gain airspeed and make air flow through the wings again. Feel free to correct me. Share this post Link to post Share on other sites
Mohd Idham 0 Report post Posted August 27, 2006 (edited) Syaz, how's your progress ?? Guys and Gals, Bernoullie's principle is the main equation use by aero engineers to predict behavior of an aircarft ( actually, also by Fluids Engineers - flow inside pipeline ). That equation is a general equation that relate to Fluids, including AIR FLOW, in other word, AERODYNAMICS. Most of you have got it, the air at upper surface travel faster than lower surface, the thing is, fluids that has less speed produce MORE pressure. In this case, lower surface push the upper surface upward.. When this force is equal to the weight of an aircraft, the aircraft fly..( pilot says 'rotate' ).. Aircraft must gain speed, the more speed you have, the more pressure you'll get under the wing. Why ? because the faster air travel at the upper surface, the less pressure it gets. Why aircraft have flaps and slats ? To make the wing has more curve. the different between speed of those two surfaces is greater. It means, airspeed at the upper surface travel faster, and at the lower surface travel slower. The different of pressure is greater.. Remember, the greater differents in speed (of the surfaces), the greater pressure you'll get. Extending flaps and slats produce drags ? Yes, LIFT always comes with DRAG. like romeo and juliet. On final approach, flaps and slats in full position, produce maximum amount of LIFT. why ? because you want to landing, as slow as you get, the better it is. so, to maintain aircraft in the air at low speed, you need the maximum amount of LIFT, they don't need drag at all... Why on cruising they didn't extend flaps and slats ? DRAG....on cruise, you need speed. LIFT is not important thing now (still need some). Have you ever concern a missile ? a cruise missile ? how big the wing they have compare to its body size.. or an ordinary missile. how can they fly with small set wings ? The answer is THRUST.. Edited August 27, 2006 by Mohd Idham Share this post Link to post Share on other sites
Mohd Idham 0 Report post Posted August 27, 2006 (edited) Uncle Pieter, why stall ? the answer is, the flow of air at the upper surface has broken into vortices. not in a laminar flow anymore. (high AoA). thats cause both air flow upper and lower surface can't meet at the trailing adge of the wing. If they can't meet, the wing stalled..yes u can extend both flaps and slats, but flaps and slats just increase the stall angle, not prevent aircraft from stalling.. If aircraft without flaps and slats stall at angle of attack 15 degrees, it may stall at 20 degrees if you bring down flaps and slats to the maximum.. p/s: thats all I can help for now as Aero Engineering student.. Aerodynamics is a complex topic to discuss (plus Aircraft Stability and Dynamic Control) . I've learn Aerodynamics for 4 years, its hard to conclude it inside one thread. As far as i can, I'll try my best to help you... Edited August 27, 2006 by Mohd Idham Share this post Link to post Share on other sites
Jacky Goh 0 Report post Posted August 27, 2006 how many question they will ask hoh ? ? how aircraft fly ? wat a pilot hav to do for an emergency landing ? haha Share this post Link to post Share on other sites
Tze Shan 0 Report post Posted August 27, 2006 (edited) how many question they will ask hoh ? ? wat a pilot hav to do for an emergency landing ? haha well, jacky this is an engineer interview but not cadet pilot's! haha... when my turn, they asked me bout aircraft lights. 1.what colour is the strobe light; list out the lights and name them out. Edited August 27, 2006 by Tze Shan Share this post Link to post Share on other sites
Pieter C. 5 Report post Posted August 27, 2006 - to gain airspeed and make air flow through the wings again. This is what I was looking for ... Idham: excellent explanations Share this post Link to post Share on other sites
Min Chun 0 Report post Posted August 28, 2006 Great one Idham Thanks alot for the explanation Share this post Link to post Share on other sites
Syaz 0 Report post Posted August 28, 2006 no bro...i only went for the physcomotor test..now waiting for MISPA..i meant same boat as in i also just finished form 5.. coolness~ sumhow i tot u were way older than me. hahah my bad.. btw wish u all the best! hope u'll be getting sum good news from them soon~ =) Share this post Link to post Share on other sites
Syaz 0 Report post Posted August 28, 2006 Syaz, how's your progress ?? Guys and Gals, Bernoullie's principle is the main equation use by aero engineers to predict behavior of an aircarft ( actually, also by Fluids Engineers - flow inside pipeline ). That equation is a general equation that relate to Fluids, including AIR FLOW, in other word, AERODYNAMICS. Most of you have got it, the air at upper surface travel faster than lower surface, the thing is, fluids that has less speed produce MORE pressure. In this case, lower surface push the upper surface upward.. When this force is equal to the weight of an aircraft, the aircraft fly..( pilot says 'rotate' ).. Aircraft must gain speed, the more speed you have, the more pressure you'll get under the wing. Why ? because the faster air travel at the upper surface, the less pressure it gets. Why aircraft have flaps and slats ? To make the wing has more curve. the different between speed of those two surfaces is greater. It means, airspeed at the upper surface travel faster, and at the lower surface travel slower. The different of pressure is greater.. Remember, the greater differents in speed (of the surfaces), the greater pressure you'll get. Extending flaps and slats produce drags ? Yes, LIFT always comes with DRAG. like romeo and juliet. On final approach, flaps and slats in full position, produce maximum amount of LIFT. why ? because you want to landing, as slow as you get, the better it is. so, to maintain aircraft in the air at low speed, you need the maximum amount of LIFT, they don't need drag at all... Why on cruising they didn't extend flaps and slats ? DRAG....on cruise, you need speed. LIFT is not important thing now (still need some). Have you ever concern a missile ? a cruise missile ? how big the wing they have compare to its body size.. or an ordinary missile. how can they fly with small set wings ? The answer is THRUST.. hehe thanx idham for ambil berat (my english is still bad... ) but i havent even gone to the interview yet. it's gonna be on this wednesday... so yea been busy with my campus life here.. and some preparation for the interview of course. hopefully, everything's gonna be alright.. =) wish me luck!! heheh ur explanation really helps a lot. this whole topic does, in fact. Thanx!! Share this post Link to post Share on other sites
Tony 1 Report post Posted August 29, 2006 good luck with ur interview, Syaz Share this post Link to post Share on other sites
Mohd Idham 0 Report post Posted August 29, 2006 Syaz, maybe they will ask you this.. "If the aircraft schedule to fly at 1400LT, and now is 1315LT. Both pilots is in cockpit doing preparation. you noticed some defect on engine #2. and it will take about 3 man hours to repair it. Todays flight is the most important flight for the company and our country. and there is no replacement for another aircraft.. What will you do ? " Share this post Link to post Share on other sites
William Tee 0 Report post Posted August 29, 2006 i thought bernoulli principle takes into acc that the airflow from the top reaches the edge at the same time with the air from below, hence the less pressure at the top due to higher speed for airflow at top... but in actual fact, the airflow from top doesn't reach the edge at the same time as airflow from bottom, correct me if i'm wrong, but can someone explain to me what is induced lag, and mean chamberline? Share this post Link to post Share on other sites
Mohd Idham 0 Report post Posted August 29, 2006 airflow from top doesn't reach the edge at the same time as airflow from bottom That incorrect, they will reach the edge at the same time. Imagine you running on a race track 4x400m. You take the outer lane while someone else take inner lane. You must run faster then him if you want to reach the finish line together. Its as simple as like that. Air flow at the top surface must travel further and faster compare to the bottom surface. Why? the distance is longer because of the chamber of the wing. And the result, pressures drop.. Induced Drag. Drag that caused from LIFT. or known as Aerodynamic Drag. It will always come with LIFT..the higher the LIFT, the higher it will be.. Mean chamber line. First you must know chord line. Chord line is a straight line from leading edge to trailling edge. Chamber line is also the same thing (leading to trailling edge) but in a curve form. The maximum height of the curve normally located at 1/3 (one third) of the chord line from leading edge. The function of flaps and slats is to makes variable chamber line.. Share this post Link to post Share on other sites
William Tee 0 Report post Posted August 29, 2006 That incorrect, they will reach the edge at the same time. Imagine you running on a race track 4x400m. You take the outer lane while someone else take inner lane. You must run faster then him if you want to reach the finish line together. Its as simple as like that. Air flow at the top surface must travel further and faster compare to the bottom surface. Why? the distance is longer because of the chamber of the wing. And the result, pressures drop.. Induced Drag. Drag that caused from LIFT. or known as Aerodynamic Drag. It will always come with LIFT..the higher the LIFT, the higher it will be.. Mean chamber line. First you must know chord line. Chord line is a straight line from leading edge to trailling edge. Chamber line is also the same thing (leading to trailling edge) but in a curve form. The maximum height of the curve normally located at 1/3 (one third) of the chord line from leading edge. The function of flaps and slats is to makes variable chamber line.. tq for explaination but imagine this, we make assumption that it will come out at the same time, that's why it's not accurate, from my understanding the one that makes aeroplane fly is Velocity Share this post Link to post Share on other sites
Syaz 0 Report post Posted August 29, 2006 (edited) Guess this is gonna be my last entry before the interview.. will be leaving my campus in half an hour. I think im around 85% ready at the moment so hopefully it'll be increased tomorrow. good luck with ur interview, Syaz Thanx a lot!!! Syaz, maybe they will ask you this.. "If the aircraft schedule to fly at 1400LT, and now is 1315LT. Both pilots is in cockpit doing preparation. you noticed some defect on engine #2. and it will take about 3 man hours to repair it. Todays flight is the most important flight for the company and our country. and there is no replacement for another aircraft.. What will you do ? " Mmm... kay I'll think of the answer during my journey back to KL~ hahah Again, thanx a lot guys. *Group hug* Edited August 29, 2006 by Syaz Share this post Link to post Share on other sites
Mohd Idham 0 Report post Posted August 29, 2006 Actually, where are you staying right now Syaz ? where is your campus ? Share this post Link to post Share on other sites
Brennan Raj 0 Report post Posted August 29, 2006 hehe thanx idham for ambil berat (my english is still bad... ) but i havent even gone to the interview yet. it's gonna be on this wednesday... so yea been busy with my campus life here.. and some preparation for the interview of course. hopefully, everything's gonna be alright.. =) wish me luck!! heheh ur explanation really helps a lot. this whole topic does, in fact. Thanx!! Alll the luck goes to u man!!!Do your best and hope 4 the best... Share this post Link to post Share on other sites
Gavin Andrew David 6 Report post Posted August 29, 2006 tq for explaination but imagine this, we make assumption that it will come out at the same time, that's why it's not accurate, from my understanding the one that makes aeroplane fly is Velocity William , its not an assumption . It is a fact Are you an engineering student ? Share this post Link to post Share on other sites
William Tee 0 Report post Posted August 29, 2006 William , its not an assumption . It is a fact Are you an engineering student ? hahaha ... no way lar... i'm just bought a few books and did my own reading and will try to find a way to get a CPL by hook or by crook... will keep on crossing my fingers till i get a a pilot post Share this post Link to post Share on other sites
