Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: earl1937 on September 15, 2013, 12:58:29 PM
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:airplane: I am told that from time to time, people in here like to read things and think about things other than whines and etc, so, here are a few questions to ponder!
#1- Why did Consolidated put 2 vertical stabs and 2 rudders on their B-24 aircraft?
#2- Why did the B-24 have "desk" top, roll up bomb day doors?
#3- On the B-17G, there is a glass dome just in front of the wind shield, what is it for and how is it used.
#4- What does the term: "just returned from IRAN" mean?
#5- All commercial aviation in the U.S. flies under 2 FAR's, part 121 and part 135. Which aircraft flies under which FAR?
#6- If you start a left turn in a B-29, B-17, JU-88, HElll, or a B-24, with ailerons only, which way will the aircraft's nose turn first and why?
#7- There is an antenna just in front of the glass dome on the B-17, shaped like a boomerang, what is it and how is it used?
#8- There is an antenna running from the top of the dorsal area to the top of the vertical stabilizer, what is it and what is it for? (actually, 2 wires)
#9- Why did the P-47 jugs, in Italy, have a history of runway over runs due to brake failure and what was the cure?
#10- Just below the copilots window, along the lower side of the fuseledge of the B-17, there is a "bullet" shaped object. What is it and how is it used?
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:airplane: I am told that from time to time, people in here like to read things and think about things other than whines and etc, so, here are a few questions to ponder!
Without touching a book....
#1- Why did Consolidated put 2 vertical stabs and 2 rudders on their B-24 aircraft?
Wasn't the tail simply borrowed from the Consolidated XP4Y?
#2- Why did the B-24 have "desk" top, roll up bomb day doors?
The obvious reduction in drag, as well as buffeting.
#3- On the B-17G, there is a glass dome just in front of the wind shield, what is it for and how is it used.
Celestial navigation... Shooting the stars.
#6- If you start a left turn in a B-29, B-17, JU-88, HElll, or a B-24, with ailerons only, which way will the aircraft's nose turn first and why?
Yaw right.
#7- There is an antenna just in front of the glass dome on the B-17, shaped like a boomerang, what is it and how is it used?
ILS antenna, I believe.
#8- There is an antenna running from the top of the dorsal area to the top of the vertical stabilizer, what is it and what is it for? (actually, 2 wires)
HF antenna. VHF was on top of the fuselage, IIRC.
#10- Just below the copilots window, along the lower side of the fuseledge of the B-17, there is a "bullet" shaped object. What is it and how is it used?
Are you referring to the pitot tubes?
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Without touching a book....
#1- Why did Consolidated put 2 vertical stabs and 2 rudders on their B-24 aircraft?
Wasn't the tail simply borrowed from the Consolidated XP4Y?
#2- Why did the B-24 have "desk" top, roll up bomb day doors?
The obvious reduction in drag, as well as buffeting.
#3- On the B-17G, there is a glass dome just in front of the wind shield, what is it for and how is it used.
Celestial navigation... Shooting the stars.
#6- If you start a left turn in a B-29, B-17, JU-88, HElll, or a B-24, with ailerons only, which way will the aircraft's nose turn first and why?
Yaw right.
#7- There is an antenna just in front of the glass dome on the B-17, shaped like a boomerang, what is it and how is it used?
ILS antenna, I believe.
#8- There is an antenna running from the top of the dorsal area to the top of the vertical stabilizer, what is it and what is it for? (actually, 2 wires)
HF antenna. VHF was on top of the fuselage, IIRC.
#10- Just below the copilots window, along the lower side of the fuseledge of the B-17, there is a "bullet" shaped object. What is it and how is it used?
Are you referring to the pitot tubes?
:airplane: #1- 3 reasons, speed,(low profile of tail assy), better field of fire for top turret, and since this was first tricycle landing geared bomber, the height of the tail assy had to be taken into consideration, as during that period of design time, most a/c hangar doors were no more than 20 feet high, as most a/c had a tail wheel and the tail assy was no problem.
#2- The bomb bay doors were indeed designed with drag considerations in mind, but reason #1 was access to the bomb bay by ords dollys for loading of bombs and being an "over the shoulder" winged a/c, it naturally had little clearance between the ground and fuselage.
#3- Correct
#4- IRAN is short for "inspection and repair as necessary".
#5-FAR 121 concerns scheduled airlines such as Delta, United, etc. FAR 135 concerns unscheduled, on demand type of commercial flights.
#6- Correct, adverse yaw created by the "down" aileron.
#7- Very High Freq antenna.
#8- Low frequency antenna
#9- Runways on some bases in Italy had steel matted type runways. during takeoff, the tires would "grow" from heat and as gear was raised, sometimes hydraulic line was "rubbed" and a leak resulted. Fix was just simply touching brakes after takeoff, prior to raising gear.
#10- ADF antenna. Spawn out on runway, engage F3, use hat switch to move to right side of a/c and it is in plain view.
Sorry for the post guys, was just trying to start a dialog about some of these questions.
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I expected you to mention the trailing wire antenna the -17 and -24 had.
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:airplane:
I expected you to mention the trailing wire antenna the -17 and -24 had.
:airplane: I did not include the HF antenna question for a reason, more on that later!
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To fully close the loop on question 6, it is adverse yaw, as noted in several of the replies. Common to many aircraft, it is caused by the aileron that is going down (and thus lifting that particular wing) causing more drag than the aileron that is going up (on the descending wing). This drag causes acts like an airbrake on that side, and causes the aircraft to yaw away from the desired direction of turn. Leading the turn with the rudder is the fix, and there are some design fixes as well, built into most modern airplanes. Fly by wire can remove this effect entirely for all intents and purposes by having the flight computer compensate for it.
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Also early ailerons were simple hinged flaps. An improvement is the frise aileron which dips the nose of the down aileron below the wing to add drag to balance the adverse drag of the up aileron.
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Also early ailerons were simple hinged flaps. An improvement is the frise aileron which dips the nose of the down aileron below the wing to add drag to balance the adverse drag of the up aileron.
:airplane: The adverse "yaw" is created by the down aileron, not the up aileron. The up aileron does not have as much effect because it is usually behind the separation point of lift on that wing, which means it is not getting clean air like the down aileron.
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By up and down I mean what the effect on lift is. Left stick means the right aileron is the up one and the left aileron is the down one in my post which is approximately the reverse of how DurrD put it, sorry for the shorthand.
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One documentary I watched said that the B24 had roll up bomb-bay doors so that enemy fighters wouldn't know when the bomb-bay was open (and thusly the aircraft was more succeptable to attack).
The B-24 had twin tails for a better field of fire for the top turret gunner and also to reduce vertical stabilizer height (Good grief, ever see how tall the vertical stab on the Navy PB4Y is?).
The longer the antenna, the lower the frequency. Even with HF frequencies, you can talk thousands of miles (especially in an aircraft).
The plexiglass dome on the front of the B17 was like Widewing said, celestial navigation.
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One documentary I watched said that the B24 had roll up bomb-bay doors so that enemy fighters wouldn't know when the bomb-bay was open (and thusly the aircraft was more succeptable to attack).
The B-24 had twin tails for a better field of fire for the top turret gunner and also to reduce vertical stabilizer height (Good grief, ever see how tall the vertical stab on the Navy PB4Y is?).
The longer the antenna, the lower the frequency. Even with HF frequencies, you can talk thousands of miles (especially in an aircraft).
The plexiglass dome on the front of the B17 was like Widewing said, celestial navigation.
:airplane: What u say about fighters attacking bombers with doors open first might be true, but take a look at the following picture and see why they have roll up doors!
(http://i1346.photobucket.com/albums/p684/earl1937/b24_zpsb64acff2.jpg) As you can see, very little clearance below bomber for hinged doors!
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One documentary I watched said that the B24 had roll up bomb-bay doors so that enemy fighters wouldn't know when the bomb-bay was open (and thusly the aircraft was more succeptable to attack).
The B-24 had twin tails for a better field of fire for the top turret gunner and also to reduce vertical stabilizer height (Good grief, ever see how tall the vertical stab on the Navy PB4Y is?).
The longer the antenna, the lower the frequency. Even with HF frequencies, you can talk thousands of miles (especially in an aircraft).
The plexiglass dome on the front of the B17 was like Widewing said, celestial navigation.
:airplane: Pretty good answers, but on the HF answer, there are some limitations, especially if one wants to talk to someone in the U.S. from Britain for example! Following is a link from radio school in the USAF, which was taught at Keesler AFB, Biloxi, Mississippi during WW2: HF part of the spectrum can transmit signals by ground-wave or sky-wave propagation. Ground-wave propagation is effective from 30 to 300 miles. Sky-wave propagation can span the world depending on atmospheric conditions and the frequency used. HF is widely used for long-distance communications, short-wave broadcasting, over-the-horizon (OTH) radar, and amateur radio. HF transmitter power can range from as low as 2 watts to above 100kW, depending on the intended use.
In the HF range, two-way voice and data (record) communications can be supported in various ways. This includes point-to-point broadcast and air/ground/air operating modes using upper or lower sidebands. Besides long-range communications, HF is also widely used in tactical environments to supplement communications when LOS radio isn't possible or feasible.
Another HF mode is short-range near-vertical-incidence sky wave (NVIS) used with the NVIS antenna. The NVIS is useful when stations are separated by obstacles (such as mountains). When direct communication isn't possible, a NVIS antenna can radiate an HF signal almost straight up for reflection down (over a mountain peak) to another station only a few miles away. NVIS operations are most effective when using the lower HF frequencies (2 to 6MHz).
HF can accommodate IMC, voice, and teletypewriter operating modes and can operate in secure modes using a variety of available COMSEC devices. HF radios can be mounted in vehicles, ships, or aircraft and can be fixed, portable, or man pack configured. Transmissions are normally in either the single sideband (SSB) or independent sideband (ISB) mode.
HF sky-wave propagation is extremely vulnerable to intercept, particularly the high-powered, long-haul systems. The HF part of the spectrum is currently the frequency band most susceptible to jamming. Electronic countermeasure (ECM) jammers far from the receiver can jam or disrupt HF sky-wave communications. Proper use of COMSEC devices and burst transmission techniques can reduce this vulnerability however. Without some form of anti-jam protection, HF communications aren't considered suitable for critical C2 systems.
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To fully close the loop on question 6, it is adverse yaw, as noted in several of the replies. Common to many aircraft, it is caused by the aileron that is going down (and thus lifting that particular wing) causing more drag than the aileron that is going up (on the descending wing). This drag causes acts like an airbrake on that side, and causes the aircraft to yaw away from the desired direction of turn. Leading the turn with the rudder is the fix, and there are some design fixes as well, built into most modern airplanes. Fly by wire can remove this effect entirely for all intents and purposes by having the flight computer compensate for it.
Adverse yaw is greatest when you roll to set your bank angle. The roll creates more lift on the rising wing. The wing with more lift has more induced drag. Once the roll is stopped the lift is more equal between the wings and the yaw is greatly reduced until it's reversed by rolling out of the bank.
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Adverse yaw is greatest when you roll to set your bank angle. The roll creates more lift on the rising wing. The wing with more lift has more induced drag. Once the roll is stopped the lift is more equal between the wings and the yaw is greatly reduced until it's reversed by rolling out of the bank.
:airplane: Well, not sure how to answer this reply, but: the wing produces, (in lay terms), relative lift, which holds the aircraft in flight, and resultant lift, which turns the aircraft! Lift is what turns the aircraft, not the controls, all the controls do is put the aircraft in the desired attitude to produce the performance that the pilot wants from that attitude. Relative lift always works vertically from the top of the wing. Example: if a wing is 60 feet long, in a 45 degree bank, you have effectively reduces the lifting area by 30 feet, hence the reason for back pressure on the elevator to compensate for the loss of relative lift, you have to increase the angle of attack of the 30 foot wing, to hold the aircraft in the air that was designed for a 60 foot lifting area. The resultant lift always acts 90 degrees to the wing. Again, as in a turn, the reason for the back pressure on the elevator is to compensate for loss of relative lift by changing the angle of attack of the wing to maintain constant altitude. The resultant lift will remain the same though out the turn unless some outside force acts on the wing to disturb the bank angle, turbulence for example can and does change the bank angle with out the pilot making any control inputs.
The main thing that any pilot should understand is the wing's lift is what turns the aircraft, not the flight controls. Now, in the case of 90 degree bank and applying back pressure to create and maintain the turn, you are talking about an all together different set of aerodynamics which affect the aircraft. What we are discussing here are prop driven aircraft! I don't think we need to get into wing "spoilers" and their effect on the aircraft, but they to, have an effect on aircraft yaw when starting a turn, but as I understand it, it actually has the opposite affect of the aileron controlled aircraft. Example: when starting a left turn with a spoiler controlled wing, the spoilers on the left wing come up to decay the lift on the left wing, and the pilot, because of the drag of the up spoiler, now has to apply a small amount of right rudder to compensate so as to stay coordinated during the turn. Maybe some these jet jockeys which are playing the game can weight in on that and explain it for us all.
I don't think, and wind tunnel tests have proved this: starting, during and recovering from a banked turn in aircraft, one wing does not produce more lift than the other!
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http://en.wikipedia.org/wiki/Adverse_yaw
Here you go Earl.
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Wikipedia confuses me. The thing about the lift vectors: "By definition, lift is perpendicular to the oncoming flow.[1]:18 As the left wing moves up, its effective angle of attack is decreased,[1]:361 so its lift vector tilts back. Conversely, as the right wing descends, its lift vector tilts forward. The result is an adverse yaw moment to the left, opposite to the intended right turn."
I am confused because I don't know if this refers to an instant in time or a sustained turn and it seems to contradict how I understood it all.. I thought that deflecting the left ailerons trailing edge down increased the angle of attack of the airfoil at its location causing it to create more lift and drag and producing a rolling moment and a yawning moment. I can see how the upward motion of the wing would change the angle of the relative wind but only while the wing is rising in the roll. In a steady banked turn the outside wing travels a greater distance than the inside so it's relative wind should be faster causing more lift and keeping the plane in a bank and in a plane with neutral stability causing the plane to roll further. The wiki description seems to contradict this. Also this tilting lift vector thing, if the wing is flying at a reduced angle of attack but the same relative wind velocity wouldn't it be producing less lift so the magnitude of the rearward component be less despite the vector they are calling lift being tilted? I feel I am missing something here.
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It refers to rolling into the bank at the start of the turn and rolling out at the end. That's the bit you're missing.
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Wikipedia confuses me. The thing about the lift vectors: "By definition, lift is perpendicular to the oncoming flow.[1]:18 As the left wing moves up, its effective angle of attack is decreased,[1]:361 so its lift vector tilts back. Conversely, as the right wing descends, its lift vector tilts forward. The result is an adverse yaw moment to the left, opposite to the intended right turn."
I am confused because I don't know if this refers to an instant in time or a sustained turn and it seems to contradict how I understood it all.. I thought that deflecting the left ailerons trailing edge down increased the angle of attack of the airfoil at its location causing it to create more lift and drag and producing a rolling moment and a yawning moment. I can see how the upward motion of the wing would change the angle of the relative wind but only while the wing is rising in the roll. In a steady banked turn the outside wing travels a greater distance than the inside so it's relative wind should be faster causing more lift and keeping the plane in a bank and in a plane with neutral stability causing the plane to roll further. The wiki description seems to contradict this. Also this tilting lift vector thing, if the wing is flying at a reduced angle of attack but the same relative wind velocity wouldn't it be producing less lift so the magnitude of the rearward component be less despite the vector they are calling lift being tilted? I feel I am missing something here.
:airplane: If you read my post in this thread about adverse yaw and lift effects during a turn, that should clear it up for you. Don't know who posted that explanation on Wiki, but it is not quite true. consult the wind tunnel tests conducted by both Lockheed and Boeing during the 50's and you can't argue with that! I have trained hundreds of pilots, from primary to Airline Transport certificate and so far as I know, not one has had an accident! A student pilot is not interested in engineering answers, only answers to questions that they can picture mentally in their mind. The use of the terms "relative lift and resultant lift" makes it pretty clear in the students mind as to what is happening during a turn. Now we could get into all kinds of engineering explanations concerning subjects in this forum, but the vast majority of players in here are not studying to be engineers!!LOL
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It's basic pilot stuff Earl, it's not engineering, and it's modeled in Aces High so anybody can see it by watching the ball.
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It's basic pilot stuff Earl, it's not engineering, and it's modeled in Aces High so anybody can see it by watching the ball.
:airplane: OK, my friend, won't argue the point anymore with you, BTW, how many real life pilots have you trained?
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:airplane: OK, my friend, won't argue the point anymore with you, BTW, how many real life pilots have you trained?
I've only trained a few real pilots. They have all been polite, respectful, and happy to learn something new.
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:airplane: OK, my friend, won't argue the point anymore with you, BTW, how many real life pilots have you trained?
And how many flight sims have you written Earl.
HiTech
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And how many flight sims have you written Earl.
HiTech
:airplane: I have written several curriculum's and training syllabus which were approved by the Federal Aviation Agency. Not trying, although it looks like it, to argue with anyone on this subject, just going on real life experences. I am surprised at you Hi Tech, being a pilot your self, but as you just pointed out, big, big difference in flight sim's and the real thing. My problem has been since I have been in this game, is to regard it as a training tool and recreactional site for both experienced and non-pilots, and I have just tried, as I did for 60 years, pass on my experences as I saw and lived them.
This is the best flight sim on line, that I can find and experience, its just a shame that more people out in the real world, have not a clue about this game. I bet there are some good marketing ideas which would be presented right here, if you gave people an opportunity to help build this game to the ultimate flight sim!
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Earl if you check with the FAA you'll find that adverse yaw is a product of the greater lift on the rising wing creating more drag.
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Earl if you check with the FAA you'll find that adverse yaw is a product of the greater lift on the rising wing creating more drag.
:airplane: Unless they have changed the FAA written exam for both private and commercial written exams, that question is there, and the correct answer is of course the rudder to correct for the adverse yaw created by the down aileron. :salute
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:airplane: Unless they have changed the FAA written exam for both private and commercial written exams, that question is there, and the correct answer is of course the rudder to correct for the adverse yaw created by the down aileron. :salute
And the reason for that is that the down aileron raises the wing creating more lift and drag as it rises than the descending wing. Once the bank is established you have less yaw because the lift is equal on the wings while maintaining the bank. I'm sure you know that you use more rudder entering the turn than maintaining it.
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..... My problem has been since I have been in this game, is to regard it as a training tool and recreactional site for both experienced and non-pilots,
Earl first off :salute for your enthusiasm....
just wanna say.....This game is about 1 thing and 1 thing only....Virtual Combat......using ww2 equipment, with excellent FM....its not a training tool nor is it meant to be....its not WW2 online....nor is it meant to be....its not a flight sim....or any sim for that matter it is a game above all else....
just something to think about(because you are gonna get highly frustrated if you continue to think that this game is supposed to be a "sim" )
:salute
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This is the ultimate BBS thread, because it exemplifies what people have been repeating for years and years "How would you know, you've never flown a World War II plane before". Now we have a real life Air Force pilot, who has flown B-29s, A-26s, and even the ultra-rare P-82, and people are trying to tell him how the planes actually flew. LOL. Earl1937 I find your threads extremely interesting, and try to read every one of them. Keep up the good work sir!
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This is the ultimate BBS thread, because it exemplifies what people have been repeating for years and years "How would you know, you've never flown a World War II plane before". Now we have a real life Air Force pilot, who has flown B-29s, A-26s, and even the ultra-rare P-82, and people are trying to tell him how the planes actually flew. LOL. Earl1937 I find your threads extremely interesting, and try to read every one of them. Keep up the good work sir!
DaveBB:Earl is a very enthusiastic player and a very experienced pilot.I would never wish to debate Earl on best practices when piloting aircraft.And I would love to fly with Earl in my RV.
I have been wanting to make a series of video , mostly on where to look when performing maneuvers, hence the head cam. Here is my first attempt.
http://www.youtube.com/watch?v=ulpdOHcCiNE
But I do not see anyone telling early how a plane flew or how to fly a plane. I see a technical discussion of aerodynamics about what make planes fly. In this particular case, adverse yaw. A pilot must be taught about adverse yaw so as to know he must apply rudder to compensate for it. Thinking and remembering that a downward aileron causes drag is a good way to remember.
But i have learned that most pilots only have a basic understanding of the physics of flight. Pilots are taught in a way that they understand the basics of physics as is required to best operate an airplane. The diagram on the wiki sight is 100 % correct. But it also does not tell the entire story. It is showing what causes adverse yaw in a steady state roll. There is also adverse yaw immediately when applying aileron Pryor to the roll developing . This is basically do to the downward deflected aileron. But more accurately it is do to the shifting of the lift vs AOA curve due to the increase camber of the wing caused by the downward deflected aileron. This lift curve shift creates more lift & hence more induced drag and possibly more profile/parasitic drag. Once the roll is steady state, (not a steady state turn but ROLL) then both wings must be producing approximately the same lift or the roll would be increasing or decreasing in RPM. The AOA is greater on one wing vs the other , but the camber is greater on the lower AOA wing so both are creating the same lift. The steady state condition is what the wiki is describing. Also that diagram is very similar to why makes a helicopter auto rotate.
Now notice this quote from early "Don't know who posted that explanation on Wiki, but it is not quite true". With out any physics explanation of why he thinks it is not true. And when debated Earl simply states i have all this back ground I teach ,I fly and I have written articles.
HiTech
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Nice video. :aok
Nice mirrors. :D
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DaveBB:Earl is a very enthusiastic player and a very experienced pilot.I would never wish to debate Earl on best practices when piloting aircraft.And I would love to fly with Earl in my RV.
I have been wanting to make a series of video , mostly on where to look when performing maneuvers, hence the head cam. Here is my first attempt.
http://www.youtube.com/watch?v=ulpdOHcCiNE
But I do not see anyone telling early how a plane flew or how to fly a plane. I see a technical discussion of aerodynamics about what make planes fly. In this particular case, adverse yaw. A pilot must be taught about adverse yaw so as to know he must apply rudder to compensate for it. Thinking and remembering that a downward aileron causes drag is a good way to remember.
But i have learned that most pilots only have a basic understanding of the physics of flight. Pilots are taught in a way that they understand the basics of physics as is required to best operate an airplane. The diagram on the wiki sight is 100 % correct. But it also does not tell the entire story. It is showing what causes adverse yaw in a steady state roll. There is also adverse yaw immediately when applying aileron Pryor to the roll developing . This is basically do to the downward deflected aileron. But more accurately it is do to the shifting of the lift vs AOA curve due to the increase camber of the wing caused by the downward deflected aileron. This lift curve shift creates more lift & hence more induced drag and possibly more profile/parasitic drag. Once the roll is steady state, (not a steady state turn but ROLL) then both wings must be producing approximately the same lift or the roll would be increasing or decreasing in RPM. The AOA is greater on one wing vs the other , but the camber is greater on the lower AOA wing so both are creating the same lift. The steady state condition is what the wiki is describing. Also that diagram is very similar to why makes a helicopter auto rotate.
Now notice this quote from early "Don't know who posted that explanation on Wiki, but it is not quite true". With out any physics explanation of why he thinks it is not true. And when debated Earl simply states i have all this back ground I teach ,I fly and I have written articles.
HiTech
:airplane: Would love to kick the tires, light the fires and leap into the blue with you sometime! Just to set the record straight, I would refere anyone who is taking exception with me about the discussion which is going on, I refere you to this: http://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/airplane_handbook/
The is the Federal Aviation Agency basic handbook on what the instructor should be teaching his or her student! It is in PDF form, so when you visit and want to view, right click on 1-3, save target as! The PDF will open up and you can view all the different subjects which we have been talking about. Section 3-8 is the one which references effects of the down aileron and its effects.
Any of you can test this for your self: next time you are in a/c in flight, apply a little left or right aileron and see for your self which way the nose moves FIRST! If you apply left aileron, your aircraft nose will move right FIRST, before it begins to bank to the left. The reason the nose moves right to begin with is the drag created by the down aileron, not the additional lift created by the high wing. In this chapter I am referring you to, there is a good diagram of how relative and resultant lift works on the aircraft wing.
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The reason the nose moves right to begin with is the drag created by the down aileron, not the additional lift created by the high wing.
Earl is correct. It has nothing to do with the position of the wing, however it does have something to do with generating more lift. The reason the aileron is generating more drag is exactly because it is producing more lift by changing the curvature of the portion of the wing it covers. Due to inertia the adverse yaw occurs before the roll, and this is more noticeable the heavier the plane is.
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Earl is correct. It has nothing to do with the position of the wing, however it does have something to do with generating more lift. The reason the aileron is generating more drag is exactly because it is producing more lift by changing the curvature of the portion of the wing it covers.
The down moving aileron creates drag because it is creating lift (induced) AND because the aileron is sticking out in the slip stream. It's rarely just one thing.
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"Sticking out in the slip stream" is what creates lift with the corresponding induced drag. I suppose there is some interference drag involved as well since the aileron no longer is more or less flush with the wing surface.
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"Sticking out in the slip stream" is what creates lift with the corresponding induced drag. I suppose there is some interference drag involved as well since the aileron no longer is more or less flush with the wing surface.
:airplane: Guys, just apply a little left aileron and you will see the nose move RIGHT first before you start turning left! That should prove to you the aileron creates drag! That will NOT work in this Aces High game, because it is not programed.
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"Sticking out in the slip stream" is what creates lift with the corresponding induced drag. I suppose there is some interference drag involved as well since the aileron no longer is more or less flush with the wing surface.
Lift is created by angle of attack. The angle the relative wind meets the wing. It's the rolling that increases the AOA and provides more lift to the rising wing until it stops rising. There are other things going on but the issue has been the increased lift while rolling.
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So you don't think flaps increase lift... Right... Carry on then. :aok
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:airplane: Guys, just apply a little left aileron and you will see the nose move RIGHT first before you start turning left! That should prove to you the aileron creates drag! That will NOT work in this Aces High game, because it is not programed.
Try it in a Ta-152 it's easier to see with the longer wings. It is modeled.
So you don't think flaps increase lift... Right... Carry on then. :aok
Flaps do many things but lift is always a product of AOA and speed. In any case we're not discussing flaps.
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The AOA is greater on one wing vs the other , but the camber is greater on the lower AOA wing so both are creating the same lift. The steady state condition is what the wiki is describing. Also that diagram is very similar to why makes a helicopter auto rotate.
Thanks for saying steady state roll not turn, now it makes more sense. So viewed from behind in a steady clockwise roll the right wing is at a higher angle of attack and the left at a lower angle of attack so if the ailerons were in trail the plane would stop rolling? (all the other parts of the airplane and wing dihedral etc. ignored.)
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Flaps do many things but lift is always a product of AOA and speed. In any case we're not discussing flaps.
That's just it... Where do you measure AoA? ... The answer is: Relative to the chord line of the wing.
(http://flysafe.raa.asn.au/groundschool/aileron2.gif)
What then happens when you lower an aileron (or a flaps)? You lower the trailing edge of that part of the wing, thus changing the angle of the chord-line of that part of the wing, thus increasing the AoA, thus increasing lift, thus increasing induced drag, thus making the plane yaw towards that wing... Voilą! Adverse yaw!
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Relative lift always works vertically from the top of the wing. Example: if a wing is 60 feet long, in a 45 degree bank, you have effectively reduces the lifting area by 30 feet,
21 feet sin(45)=.707
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Thanks for saying steady state roll not turn, now it makes more sense. So viewed from behind in a steady clockwise roll the right wing is at a higher angle of attack and the left at a lower angle of attack so if the ailerons were in trail the plane would stop rolling? (all the other parts of the airplane and wing dihedral etc. ignored.)
Clockwise the right wing is descending so it's reversed. Also you generally keep a little aileron to offset the roll from the prop.
That's just it... Where do you measure AoA? ... The answer is: Relative to the cord line of the wing.
What then happens when you lower an aileron (or a flaps)? You lower the trailing edge of that part of the wing, thus changing the angle the cord-line of that part of the wing, thus increasing the AoA, thus increasing lift, thus increasing induced drag, thus making the plane yaw towards that wing... Voilą! Adverse yaw!
As you said, it's the increased AOA that creates more lift. The AOA that counts is relative to the 0 lift AOA. Lowering flaps changes the attitude for the 0 lift AOA. It seems like more lift from flaps, but the result is more lift from greater AOA.
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And it is that added lift that creates more induced drag, not "sticking out in the slip stream"... I could even ask what "slip stream" WTF are you talking about? A slipstream is the wake of an object moving through a fluid.
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Clockwise the right wing is descending so it's reversed. Also you generally keep a little aileron to offset the roll from the prop.
Man, I used to be able to build mechanisms in my head and watch the gears turn and levers move. Now it seems like simple 3d visualizations are beyond my grasp. I'm watching the wing move down and watching the streamlines hit it and yes it IS flatter but 20 seconds ago it looked like it was canted at 60 degrees. Not to over share but the first time I realized I was losing it was when I looked at my mothers car which had a cracked torsion tube arm and realized I could not effortlessly see the motion of the suspension parts, that was 10 years ago its only getting worse.
Anyway leave out the prop, would it stop rolling if the ailerons were not deflected?
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Anyway leave out the prop, would it stop rolling if the ailerons were not deflected?
Do you stop rolling when you center your stick?
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Do you stop rolling when you center your stick?
I would have to say that depends. There is so much more happening in an airplane than just the abstraction of the rolling wings. So I'm asking about the abstract model of the rolling wings without things like dihedral or the empennage or gravity. My intuition says it stops rolling, my logic says that with one wing at a higher aoa than the other and no modifications in wing camber/aoa in the aileron area than one wing will be generating more lift than the other and now and now....I look at the wikipedia adverse yaw diagram again and it says the ascending wing has a lower effective AOA which is what I thought till you said I had it backwards and then I thought it was the ascending wing which had a higher AOA and now I see streamlines and a wing moving down and it looks like a higher AOA to me again. So my logic right now says that: ailerons in trail, the descending wing is at a higher AOA than the ascending wing so a moment opposite the direction of rotation is created thus stopping rotation. One post back my intuition would have been the same but my logic would have said that the spinning would get faster.
To be young again.
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The wing rotating down will obviously have a higher AoA than the wing rotating up (from the point of view of the pilot). The ailerons have to fight this effect and that is why an aircraft will not just roll faster and faster, but stabilize after a short time to its maximum roll rate where these forces are in balance. Center the stick and the plane will stop rolling, but not instantly; the difference in AoA between the wings gradually equalize as the rotation slows.
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the difference in AoA between the wings gradually equalize as the rotation slows.
Thank you. That is what I thought originally.
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And it is that added lift that creates more induced drag, not "sticking out in the slip stream"... I could even ask what "slip stream" WTF are you talking about? A slipstream is the wake of an object moving through a fluid.
If you really think a deflected aileron doesn't cause drag how do you think a speed brake works? It sure as heck isn't due to lift.
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How can you possibly come to that conclusion? You even quoted me stating it creates drag! Induced drag! A "speed brake", and I assume you mean an air brake, doesn't create lift and thus no induced drag, it creates form drag.
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Do you stop rolling when you center your stick?
:airplane: No, the aircraft will stop banking or rolling when you apply opposite aileron and rudder. If you induce a 30 degree banked turn and turn the aileron back to neutral, the inherent instability of the aircraft will want to continue banking the aircraft until some outside force acts on it. i.e., flight controls. The larger the aircraft, the more stable in bank maintenance when making a turn, but that is due to a number of factors, non of which are mentioned here. Most hi speed aircraft must have a small amount of opposite aileron to maintain a certain bank angle. The only way an aircraft stops rolling when you center the ailerons is, and there is dihedral in the wing, which helps it stay in stable level flight, it will eventually return to level flight.
The Piper series of a/c, the PA's are and were successful to the flying public and inexperienced pilots because they were easier to maintain level flight because of the dihedral of the wing. The P-39 we have here in Aces High has a very pronounced wing dihedral and why it is not a popular "dog fighter" against other aircraft.
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So you don't think flaps increase lift... Right... Carry on then. :aok
:airplane: I don't think that is what he means. Flaps will increase lift from the fuseledge outward to the point where the flaps end, provided you do not extend the flaps to the point of producing more drag than lift. Flaps change the "camber" of the wing next to the fuseledge, because wings which are designed correctly, are designed to stall from the wing root outward, so that the pilot can maintain aileron control though out the low speed ranges. Factory test pilots and wind tunnel test show the aircraft manufacturer the maximum extension of flaps before drag overcomes the benefit of added lift.
The B-29 we have here in Aces High is a good example of incorrect flap setting for takeoff. At a takeoff weight of 124,500 lbs in the real B-29, we used 18 degrees of flap because Boeing says anything over that produces more drag than lift.
I see people in here crash because the aircraft, the 29, when it spawns out on the runway, it automatically lowers 50% of flaps! That is all well and good, as ground effect will allow the 29 to get off the ground quicker, but when you have to "milk" the flaps up to accelerate to climb speed, you have to raise flaps 25% at a time, which allows the aircraft to settle back into the ground unless the pilot is very skilled in the slow flight realm of the 29. When I post a 29 mission in the game, I advise the guys to raise flaps all the way up, engage auto takeoff, full power, engage wep and leave it alone, it will climb out just fine, even from a medium size field. If they want to use 25% flaps, OK, but don't raise them until you get at least 1,000 feet AGL.
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21 feet sin(45)=.707
:airplane: The effective lifting area is 30 feet when in a 45 degree bank, as measure vertically from the wing up! The point being that the wing doesn't produce lift in a 45 degree bank, as it does in level flight. The point is to make the student pilot understand that to overcome the loss of lift, by the banked wing, is to either add elevator back pressure in order to maintain altitude, at which point the aircraft will slow and more back pressure on the elevator is required or you must add power to compensate for the loss of airspeed and effective lift in order to maintain a constant altitude during the turn.
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I would have to say that depends. There is so much more happening in an airplane than just the abstraction of the rolling wings. So I'm asking about the abstract model of the rolling wings without things like dihedral or the empennage or gravity. My intuition says it stops rolling, my logic says that with one wing at a higher aoa than the other and no modifications in wing camber/aoa in the aileron area than one wing will be generating more lift than the other and now and now....I look at the wikipedia adverse yaw diagram again and it says the ascending wing has a lower effective AOA which is what I thought till you said I had it backwards and then I thought it was the ascending wing which had a higher AOA and now I see streamlines and a wing moving down and it looks like a higher AOA to me again. So my logic right now says that: ailerons in trail, the descending wing is at a higher AOA than the ascending wing so a moment opposite the direction of rotation is created thus stopping rotation. One post back my intuition would have been the same but my logic would have said that the spinning would get faster.
To be young again.
:airplane: Consider this! If you are in a Hurricane, the real aircraft, which has zero dihedral, and you induce a 30 degree bank to the left and then take your hands and feet off the flight controls, two things will happen: #1- the bank angle will continue to increase, #2- your nose in relation to the horizon will decrease, therefore inducing additional speed. Less assume for a minute that before you started the left turn, you had the aircraft trimmed to straight and level flight, hands off. Because of the lack of dihedral, the wings will not level by themselves. Because you had the aircraft trimmed for level flight, at a certain airspeed, the nose of the aircraft will try to maintain an angle which will give you that IAS you had it trimmed for, but because of the increasing bank angle and the resulting increase in speed, the trim loses its effectiveness and you wind up with what is called a "grave yard" spiral. Take the same set of situations in a Spitfire, because of the dihedral of the wing, it will, if left alone and not exceeding the VNE, it will eventually return to the congf which you had it in before you induce the left turn! If will wander all over the sky, but eventually will return to straight and level flight.
I know this thread is not about dihedral in wings, but the dihedral does play an important part in the discussion about adverse yaw and etc in this discussion.
Again, as I have said, when in level flight, induce left aileron with no rudder, and watch what your aircrafts nose will do. It will move RIGHT first and then will begin to bank to the left, hence the explanation of "the rudders primary function is to overcome the adverse yaw, created by the down aileron".
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I would have to say that depends. There is so much more happening in an airplane than just the abstraction of the rolling wings. So I'm asking about the abstract model of the rolling wings without things like dihedral or the empennage or gravity. My intuition says it stops rolling, my logic says that with one wing at a higher aoa than the other and no modifications in wing camber/aoa in the aileron area than one wing will be generating more lift than the other and now and now....I look at the wikipedia adverse yaw diagram again and it says the ascending wing has a lower effective AOA which is what I thought till you said I had it backwards and then I thought it was the ascending wing which had a higher AOA and now I see streamlines and a wing moving down and it looks like a higher AOA to me again. So my logic right now says that: ailerons in trail, the descending wing is at a higher AOA than the ascending wing so a moment opposite the direction of rotation is created thus stopping rotation. One post back my intuition would have been the same but my logic would have said that the spinning would get faster.
To be young again.
You're right it's a lower AOA on the rising wing. The details do get complicated but the point remains that there is more yaw during the roll than the turn.
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:airplane: No, the aircraft will stop banking or rolling when you apply opposite aileron and rudder. If you induce a 30 degree banked turn and turn the aileron back to neutral, the inherent instability of the aircraft will want to continue banking the aircraft until some outside force acts on it. i.e., flight controls. The larger the aircraft, the more stable in bank maintenance when making a turn, but that is due to a number of factors, non of which are mentioned here. Most hi speed aircraft must have a small amount of opposite aileron to maintain a certain bank angle. The only way an aircraft stops rolling when you center the ailerons is, and there is dihedral in the wing, which helps it stay in stable level flight, it will eventually return to level flight.
The Piper series of a/c, the PA's are and were successful to the flying public and inexperienced pilots because they were easier to maintain level flight because of the dihedral of the wing. The P-39 we have here in Aces High has a very pronounced wing dihedral and why it is not a popular "dog fighter" against other aircraft.
Bank and dihedral effects were specifically left out of Pembquist's thought experiment. As if the aircraft was pinned in a wind tunnel only able to rotate around its roll axis. If we include bank angle and turning effects then the aircraft will weathervane into a turn resulting in faster airflow around the outside wing creating more lift, resulting in the aircraft continuing to roll into the turn (unless countered by stabilizing dihedral or low Cg) until it ends up in an inverted dive.
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Bank and dihedral effects were specifically left out of Pembquist's thought experiment. As if the aircraft was pinned in a wind tunnel only able to rotate around its roll axis. If we include bank angle and turning effects then the aircraft will weathervane into a turn resulting in faster airflow around the outside wing creating more lift, resulting in the aircraft continuing to roll into the turn (unless countered by stabilizing dihedral or low Cg) until it ends up in an inverted dive.
:headscratch: You have lost me on this explanation! Wind does not "weathervane" aircraft into a turn sir. Heat thermals, or turbulence can induce the start of a turn, or the pilot inputs some control movement. If an aircraft "weathervanes" during straight and level flight, it is a flat turn, and hardly noticeable. I think you meant to say "rear" CG instead of low CG. The only thing CG does is affect the AOA of the wing, in any maneuver. If a pilot ends up in a inverted dive, its because he did something stupid! A lot of non instrument rated pilots die each year, because they lose control of the aircraft and it winds up in a grave yard spiral or spin, usually pulling the wings off first, then becoming the famous lawn dart.
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Yes we definitely have a communication problem... I was (trying) to explain that a roll will produce a bank angle (uncoordinated turn) ... This will create a horizontal component to the lift vector pushing the aircraft sideways into the bank... This will make the plane weathervane into the bank due to the sideways motion acting on the horizontal stabilizer... This will increase the airflow over the outer wing while reducing the airflow over the inner wing further increasing the bank angle until the aircraft ends up in an inverted dive/spiral... This is if the pilot does nothing at all to correct it, or if stabilizing dihedral effect or low CG is able to counter the roll. Low CG... where CL is significantly above CG, like in most high-winged aircraft, is a stabilizing force in it self that acts as a pendulum effect which will tend to bring the aircraft back to a wings level attitude (manipulating this low CG is the only way to control a hang glider for example). Most heavyweight high-wing aircraft has to have some anhedral (drooping wings) to counter the low CG/high CL and make the aircraft less stable and more maneuverable.
This is getting tiresome. Time for a beer! :cheers:
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How can you possibly come to that conclusion? You even quoted me stating it creates drag! Induced drag! A "speed brake", and I assume you mean an air brake, doesn't create lift and thus no induced drag, it creates form drag.
Hey, all I'm saying is the aileron also produces form drag. The adverse yaw is not caused by induced drag alone.
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... I'm having a beer.
:cheers:
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The aileron produces induced drag. What other forms of drag do you think it produces? Be specific.
The same drag as a speed brake. The same drag ANYTHING stuck out into the slipstream creates. Why is this so hard for you to grasp?
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Again with the "slipstream"...
I'm having another beer, and can't be bothered right now... :cheers:
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There would be less confusion and disagreement if we were all talking about the same thing instead of six different things at the same time. :lol
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you know what they say about academia: "The fights are so vicious because so little is at stake."