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Daveo

Flaps question

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I know flaps extend and change the lift on the airplanes wings. So this is good for taking off in a mountain terrain where you need to get up quick. How about flaps for descent though?? Is this to essentially help slow the plane down?? I'm not sure when to use them and how far to extend them. Can you land without flaps extended at all?? I just need some help and some general guidelines as to when to extend them and how much at what point in the descent. On any GA aircraft I can land with them not extended at all (maybe it's because of the huge runways I land on??).I am assuming that they help slow the plane down but at this point you can use more power (like 35% power) when descending. I'm totally lost and the lessons are gettin me ticked off. If I do something just a little bit wrong he says I'm distracted and I have to start all over again and the thing loads forever.

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well, let's try to make it easy (simplified).Here's the scenario of jet airliners, example 737When departing, flaps are set to 1, 5 or 15 degrees (depending on weight, runway length, headwind). Thus you have the necessary lift for takeoff at a *much lower speed* and you don't need a long runway to lift off. Takeoff speed is then like 130 KN instead of (dunno) 180 KN. Imagine, how much less way you need to lift off. On landing, typically flaps 30 or 40 is used. While flaps 15 gives very good lift at moderate drag, flaps 30 and 40 add little more lift, but increase drag a lot. Why doing that? Landing with flaps 15, you need to go back to idle thrust to avoid speeding up. If you now need to execute a missed approach, spoolup from idle to climb thrust takes very long - like 7 seconds. That's 7 long seconds that you're hardly able to climb again. And there's a higher chance that the engine has "hickups" at around 40% N1 (technical reasons). So we set flaps 30, have increased drag, and to hold the approach speed we now need 55% thrust. If going around, spoolup from 55% to climb thrust takes less than 2 seconds, we can climb right away!Of course you can land with no flaps. Minimum clean speed of 737 is around 170 knots. For safety, we do it at 180KN. But using flaps 30, we can land with i.e. 125 KN. So *without* flaps we have a 50% more speed an therefore more than two times the kinetic energy we need to ged rid of when braking after landing. Imagine this on a wet runway ... get the point? Bigean

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Flaps give more lift the wing so allow you to fly slower without stalling as you descend to land. That also means you can fly more nose down, giving you a better view of the runway.While you can land without flaps, you'll have to approach at a higher speed and will use up more runway.The guides for each aircraft (found in the learning center) should tell you at what speeds you can lower each stage of the flaps.Don' discount the lessons and the learning guide. They are both excellent tools.Here's what it says about flaps in the learning center:FlapsFlaps change the shape of the wing, creating more lift and adding drag. These two effects allow you to fly at low airspeed and descend at a steep angle without building up speed. Flaps are not primary control surfaces

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Dave,You have a pretty good handle on what flaps do, flaps useage scenarios and the like - now take what you've learned and kick it up a notch.My advice first is to skip the lessons because they are frustrating you, and just go into free flight for now. You can come back later and work on lessons and get your pilot's license. My experience was that if I wasn't very sure of what I was going to do BEFORE I went to the lesson, I'd fail it also.Here's what I'd do:1) Get into the default Cessna Skyhawk 172 aircraft at a rural airport and turn off all AI traffic. Don't request ATC ... just take off. Get airborne, and turn the autopilot on. Doesn't matter which direction you're going ... just get in level flight at 3,000 feet going about 100 knots.2) Now ... explore the cockpit! This allows you to just get into the plane and fly around without having to worry about ATC, other planes, etc. The goal here is to become familiar with all of the aircraft's idiosyncracies, the position of all its gears, knobs and levers, the position of your seat that you like to provide you with the best view, etc.2) Once you feel like you're comfortable with the cockpit, pause the simulator in flight and open up the kneepad to the reference section (click Aircraft / Kneepad / Reference).3) Take note of the flap placard speeds. In this aircraft, they are:Degrees Speed10 11015-30 85What this means is that, before you can extend 10 degrees of flaps, you must be going 110 knots or less. The reason they have these limits is to prevent damage to the flaps from the wind. Before you can put 15-30 degrees of flaps, you must have slowed to 85 knots or less.Flaps provide you with more lift, at the expense of speed.Why is this beneficial? Well, it allows you to maintain a particular altitude with less speed. Remember, flight is just lift ... and lift is created by moving the wings through the air at a certain speed. Slow down, and you have less lift. That's where flaps come in. Flaps make alter the shape of your wing (in some cases, making the wing larger). Larger (or downsloping) wings provide more lift. Thus, you can maintain a given amount of lift with slower speed.This is especially useful when landing. The goal of any airplane is to be able to land at the slowest possible speed (just in case anything goes wrong, hey, maybe you'll survive the crash if you're going slower!)So, flaps slow you down AND make the plane fly at slower speeds. The flap speed limits give you a good hint what you should be doing to prepare for your landing. In the case of the 172, as you are approaching your airport (say 10 miles out), you should be trying to slow the aircraft down so that you can begin extending your flaps in preparation for landing.While you are looking at the kneeboard, take a look at some of the other "speed limits." You can ignore most of them for now - except STALL SPEED. This is the speed at which your plane stops generating lift because it is moving its wings through the air too slowly. If you stall, you stop moving forward and move directly towards the earth. You literally fall out of the sky.In this aircraft, in landing configuration, stall speed is 40 knots. So ... now we know the LOWEST SPEED we can fly. If maximum flaps full speed is 85 knots, and stall is 40 knots - then, halfway between is about 60-65 knots. That is the speed you want to try to land the aircraft at.When you cross the threshold of the runway, you should be going 65 knots in this aircraft. If you're too low ... don't pull up. Instead, add some throttle, as long as you don't exceed 85 knots. If you're too high - don't push the nose down. Instead, cut the power just a little bit, as long as you don't slow down to below 41 knots, you should still be able to land.The kneepad is your friend. Just like any other type of vehicle, you have to know what your plane's limits are, and what the manufacturer has designed the vehicle to do. Once you're familiar with some of the basics of your plane, it will become second nature, and you won't even think about it any more.And you'll ace your lesson, and put that snotty instructor in his place.Happy landings!Cheers,Kevin

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Even though the concepts explained above flaps are generally true, the way its used in GA aircraft is slightly different than when used for airliners.Most GA aircrafts when taking off, don't need to have flaps. You can take off clean. With the exception of Short field Take off and Soft field take off. (Check Wiki for what they mean).When landing a GA aircraft also, you may decide NOT to use flaps. However the advantage of flaps is... you can land more steep without increasing speed. Imagine you don't use flaps and you push the nose down, Guess what, your speed would increase. now with the same nose attitude if you have flaps, you can approach more steep without the baggage of additional speed. the more flaps, the more steep you can descend. Thats why its also used for Short field landing or landing on a runway that has trees in front of the runway, where you cannot approach the runway shallow and you need a steep descend.Another advantage of the flaps in a GA aircraft is...your landing speed could be slower than if you didn't have flaps.. which means its safer in as far as touching the runway. You can slow down cause it stalls at a lower IAS. The stall speed depends on clean (no flaps) or dirty (flaps) configurationWhen I have gusty winds or a strong headwind (this way I already have a slow ground speed). I do not use flaps.. when there is light winds or no wind, I use full flaps. or somewhere in between.Using full flaps when landing has its own pitfalls. IF you decide to go around and you fire wall the throttle, be prepared for the aircraft to nose up so fast, you won;t know what hit you. You need a considerable amount of force on the yoke to push it down to keep the aircraft from stalling while you clean up. There have been plenty of accidents during the go around after approaching to land on full flaps.You can take off and land a GA without the use of Flaps.. and use a method called slipping. In fact the American Decathlon (an aerobatic trainer) don't even have flaps in the aircraft.For Airliners, One of the reason for flaps when landing is Jet engines need time to spool (particularly the older engines like in the 727 or the 707s. When approaching to land if you don't use flaps, and you cut down the throttle, and when over the runway, if you decide to go around and you would fire wall the throttles, But the engine is not going to spool up in time, and you would continue descending. But if you have lots of flaps, Your approach to land would be with fairly high throttle without the baggage of the additional speed. (The flaps works like a speed breaker)... and if you have to go around, you can nose up and start cleaning up the plane (reduce the flaps slowly) since the engine is fairly well spooled up already.MannyBTW, it would help for you to land GA aircrafts like the Cessna 172 on short runways at small airfields. Don't land them on large airports.. you develop bad habits. or if you have to land there, try to land and come to a full stop within the 1500 from the runway threshold. The two blocks of lines you see on the large runway are 1000 foot markers.. the next marking is 500 feet further. Try to aim at the threshold and see where you can stop with no flaps and with full flaps. Make sure you have no headwind on at least very low head wind like 4miles an hr or even with some tailwind.

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>Dave,>>I put together a short video for you to demonstrate the proper>use of flaps on landing, and the benefits flaps provide you on>... ummm ... a short-field landing, let's say.>>http://www.youtube.com/watch?v=nahKokBGzq0>>Is that just a modified carrier mission using the c172 or where can we find a carrier in free flight. I've tried the posted suggestions but had no luck...

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Depart Norfolk, Virginia ... at 12:30pm ... on a Friday.

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The default J-3 Piper Cub is an aircraft with no flaps. The wing is rather large, so this vehicle wont't go very high or very fast, but it does take off and land in an extremely small space, and the airframe is very light-weight, without being ultralight.I remember seeing a picture of a lady who owned a Cub and loved to golf who would land her aircraft on one of the fairways of the Banff Springs Golf Course, shoot the hole, and then take off again on the same fairway. That's a really small field for an airstrip!Jeff ShylukSenior Staff Reviewer, AVSIM

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Simply put think of it as driving a car with a manual shift. When getting ready to stop you usually downshift the gears 4 to 3 to 2 etc.... Lower gears = slower moving car with higher engine RPM's. :)

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