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Aviation Forum / General / Aviation / February 2010Rotation
Do real aircraft abruptly pitch upward on take-off during rotation, or is this an artifact of my simulator? I find that I must put the stick forward slightly as soon as the nose rises, or I risk a tail strike. This is especially true on small aircraft, such as the Baron 58. Large jets seem to do the same thing, but at a slower speed. I am curious as to whether real aircraft are the same way, and if so, what the proper way is to rotate to minimize wild movements.  SignatureTranspose mxsmanic and gmail to reach me by e-mail. No they don't. MS Flightsim models are not very good. you can buy models (try Realair) that perform as they should do. Tony SignatureIndiacharlieecho@hotmail.com Tony Roberts PP-ASEL VFR OTT Night Cessna 172H C-GICE > Do real aircraft abruptly pitch upward on take-off during rotation, or > is this an artifact of my simulator? I find that I must put the stick [quoted text clipped - 3 lines] > curious as to whether real aircraft are the same way, and if so, what > the proper way is to rotate to minimize wild movements. Only if its out of trim. Make sure you are trimmed for take off and the elevator is neurtral. Not sure how you do that in MSFS though, in a real plane you let it go where it wants to go (which is based on the trim). -Robert > Do real aircraft abruptly pitch upward on take-off during rotation, or > is this an artifact of my simulator? I find that I must put the stick [quoted text clipped - 3 lines] > curious as to whether real aircraft are the same way, and if so, what > the proper way is to rotate to minimize wild movements. Another thing to consider in real aircraft is a plane trimmed for takeoff for forward CG limit while the CG is loaded close to the aft limit. The plane can be noticeablly more pitch sensitive during takeoff. The cure is to trim to the forward edge of normal take off trim setting, and prepare for a light yoke force needed for rotation. > Only if its out of trim. > Only if its out of trim. Make sure you are trimmed for take off and the > elevator is neurtral. Not sure how you do that in MSFS though, in a > real plane you let it go where it wants to go (which is based on the > trim). MSFS will let me adjust trim. How do I find out how to trim for take-off? SignatureTranspose mxsmanic and gmail to reach me by e-mail. Mxsmanic, > I am > curious as to whether real aircraft are the same way, and if so, what > the proper way is to rotate to minimize wild movements. Hey, it's a simulator, so it's gotta be just like real life. Same thing. That's why you know all about flying, especially about IFR flying. SignatureThomas Borchert (EDDH) > Mxsmanic, > [quoted text clipped - 8 lines] > -- > Thomas Borchert (EDDH) I understand where you're coming from, but simulators these days have become quite true to life. I have used MSFS many times to teach stalls, emergency procedures, aerodynamics, W+B issues, and especially IFR procedures. For the most part, these programs simulate those things (and many more) extremely well. Anyways, whats with the trend around here amongst the "regulars" to be so condescending when dealing with people of lesser knowledge? It's as if these people are so desperate to show off their vast knowledge of aviation, they'll resort to things like name-calling and sarcasm (the easy way) before trying to explain their point of view intelligently and reasonably (the hard way)... Buttman, > Anyways, whats with the trend around here amongst the "regulars" to be > so condescending when dealing with people of lesser knowledge? You have obviously missed the "Why don't voice radio communications use FM?" thread, originated by mxsmanic. SignatureThomas Borchert (EDDH) > Anyways, whats with the trend around here amongst the "regulars" to be > so condescending when dealing with people of lesser knowledge? Msxmanic, in his introductory posts here, put forth several aviation-specific claims, such as "the majority of airplane accidents are caused by poor communication," then, when repeatedly questioned about these claims, failed to provide any evidence whatsoever. Tom provided the thread titles. If you are interested go to Google groups and form your own first impressions of this individual's posting style. SignaturePeter "buttman" <nbvFOUR@gmail.com> wrote in message > Anyways, whats with the trend around here amongst the "regulars" to be > so condescending when dealing with people of lesser knowledge? It's as > if these people are so desperate to show off their vast knowledge of > aviation, they'll resort to things like name-calling and sarcasm (the > easy way) before trying to explain their point of view intelligently > and reasonably (the hard way)... The problem was that the ms person tried to act as though he had ALL of the answers, and when he was presented with fact, or was asked to back up his position, he back pedaled, but would not admit fault. It is one thing to come here with questions, and a desire to learn. It is another thing to come here with the assumption that all of the others have something to learn from you. In other words, fools are not suffered easily. He acted as a fool would. SignatureJim in NC > Do real aircraft abruptly pitch upward on take-off during rotation, or > is this an artifact of my simulator? I find that I must put the stick [quoted text clipped - 3 lines] > curious as to whether real aircraft are the same way, and if so, what > the proper way is to rotate to minimize wild movements. You may be rotating with too high velocity or out of trim. Real airplanes are designed to be stable, both static and dynamically. Simulators are designed to be less stable in order to make the "student" work harder at the scan and control inputs. A $10,000,000 full motion simulator [for a $5,000,000 airplane] flight parameters are very close to a real airplane as far as static and dynamic stability, break-away forces and momentum. Some real airplanes sit with the wing at a negative angle of attack on the ground and must be rotated to a positive AOA for take-off, perhaps to 15 degrees nose high for some jets. This is a smooth but brisk pull, new pilots in type often over-shoot the target rotation. Most light aircraft sit on the ground at a positive AOA and will take-off with very little elevator input if they are loaded and trimmed for take-off. The top of the line simulators can be made to fly just like the real thing, because the software and hardware is top line. Your desktop PC based training device uses consumer grade mechanical parts. | > Do real aircraft abruptly pitch upward on take-off during rotation, or | > is this an artifact of my simulator? I find that I must put the stick [quoted text clipped - 5 lines] | | You may be rotating with too high velocity or out of trim. > The top of the line simulators can be made to fly just like > the real thing, because the software and hardware is top > line. Your desktop PC based training device uses consumer > grade mechanical parts. The joystick works very well once the plane is in the air, so the problem is unrelated to any deficiency of the joystick. SignatureTranspose mxsmanic and gmail to reach me by e-mail. Depends on where you have the trim set which is always a compromise. If the trim is set so that there is no nose down trimming required after takeoff, then it will take quite a bit of pull to get the aircraft to rotate and in the initial climb. If the aircraft is trimmed so that only a moderate amount of force is required to rotate then it will require pushing on the yoke and retrimming after takeoff as the airplane accelerates. The trim setting is correct for one speed and configuration (power and flap) and since the airplane is accelerating, the trim is going to need to be changed. Mike MU-2 > Do real aircraft abruptly pitch upward on take-off during rotation, or > is this an artifact of my simulator? I find that I must put the stick [quoted text clipped - 3 lines] > curious as to whether real aircraft are the same way, and if so, what > the proper way is to rotate to minimize wild movements. > Depends on where you have the trim set which is always a compromise. If the > trim is set so that there is no nose down trimming required after takeoff, [quoted text clipped - 6 lines] > and since the airplane is accelerating, the trim is going to need to be > changed. Mike, I think trim is just academic is MSFS because there is no control feedback. The OP is probably setting the elevator with too much back pressure but doesn't know it because he doesn't have the feedback. Honestly, if you asked me what position the yoke is in on take off, I probably couldn't tell you. In real life we expect the yoke to go to its trim position, something that doesn't make sense in a simulator that does not have feedback controls. -Roebrt > I think trim is just academic is MSFS because there is no control > feedback. You don't need control feedback to see the response of the aircraft out the window and with the instruments, although you can get it with a force-feedback joystick. It is true that anything that requires gradual control inputs or depends on a sensation of motion or other physical feedback is difficult to simulate without advanced hardware. > The OP is probably setting the elevator with too much back > pressure but doesn't know it because he doesn't have the feedback. > Honestly, if you asked me what position the yoke is in on take off, I > probably couldn't tell you. In real life we expect the yoke to go to > its trim position, something that doesn't make sense in a simulator > that does not have feedback controls. You're saying the yoke moves on its own? SignatureTranspose mxsmanic and gmail to reach me by e-mail. "Mxsmanic" <mxsmanic@gmail.com> wrote in message > You're saying the yoke moves on its own? In an actual aircraft, yes -- in a manner of speaking. At a point on the takeoff roll prior to actual takeoff, the elevator (or stabilator) starts to "fly"when it acquires enough airflow to force a response. When that happens, the yoke will move from wherever it was (usually full down in small planes with manual controls) to whatever position is defined as neutral for that particular speed, as determined by the trim tab setting. > In an actual aircraft, yes -- in a manner of speaking. At a point on the > takeoff roll prior to actual takeoff, the elevator (or stabilator) starts > to "fly"when it acquires enough airflow to force a response. When that > happens, the yoke will move from wherever it was (usually full down in small > planes with manual controls) to whatever position is defined as neutral for > that particular speed, as determined by the trim tab setting. That seems logical. Unfortunately my joystick has only springs for feedback, and that feedback is fixed. However, I do notice a change in the view out the window and sometimes the artificial horizon as speed increases, if I have the stick substantially forward or backward, so the effects are indeed being simulated, even if I can't feel them. I suppose force-feedback might help, but I don't know how reliable or durable those are, and they can be expensive (and they are hard to find). SignatureTranspose mxsmanic and gmail to reach me by e-mail. "Robert M. Gary" <N7093v@gmail.com> wrote in news:1157992218.361147.166330 @d34g2000cwd.googlegroups.com: <Snipola> > Mike, > I think trim is just academic is MSFS because there is no control [quoted text clipped - 5 lines] > that does not have feedback controls. > -Roebrt I have a force feedback stick and if I don't trim right for the phase of flight I'm in I have to provide excessive input to maintain flight attitude. As I adjust the trim the feedback moves the stick. Trim buttons are on my stick. I can press them while lightly holding the stick and feel the stick move. I know I am in trim when the stick is centered and I have a feather touch on the stick. When properly trimmed I can let go of the stick and maintain flight attitude for 10's of seconds. I can even conrol climb and descent with power adjustment without ever touching the elevator. Or sometimes I maintain altitude with single clicks of trim. Before I got the force feedback stick, trim didn't make sense since you couldn't feel it in the controls. The hundred bucks I spent on mine were well worth the enhanced simulation experience. Flight is much smoother and landings are greased much more often. Brian Signaturehttp://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html Sed quis custodiet ipsos Custodes? > Before I got the force feedback stick, trim didn't make sense > since you couldn't feel it in the controls. > > The hundred bucks I spent on mine were well worth the enhanced > simulation experience. Flight is much smoother and landings > are greased much more often. What brand and model of stick was this? And has it been reliable? SignatureTranspose mxsmanic and gmail to reach me by e-mail. Mxsmanic, > What brand and model of stick was this? Oh? All of a sudden we have the money, eh? SignatureThomas Borchert (EDDH) >> Before I got the force feedback stick, trim didn't make sense >> since you couldn't feel it in the controls. [quoted text clipped - 4 lines] > > What brand and model of stick was this? And has it been reliable? It's a Microsoft Force Feedback 2. It's been a while since I bought it so it may not even be made anymore. Brian Signaturehttp://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html Sed quis custodiet ipsos Custodes? > It's a Microsoft Force Feedback 2. It's been a while since I > bought it so it may not even be made anymore. I note that PMDG recommends that you not use force feedback with their aircraft. According to them, it's so far from the real aircraft that it does more harm than good (at least for the large aircraft that they model). SignatureTranspose mxsmanic and gmail to reach me by e-mail. Skywise, > The hundred bucks I spent on mine were well worth the enhanced > simulation experience 100 $??? You must be part of the idle rich. Mxsmanic isn't. SignatureThomas Borchert (EDDH) > "Robert M. Gary" <N7093v@gmail.com> wrote in news:1157992218.361147.166330 > @d34g2000cwd.googlegroups.com: [quoted text clipped - 32 lines] > > Brian I don't understand what non-force feedback joysticks you guys are using but my MS stick is not force feedback and if I don't trim I have to move the stick to a non-centered position which requires constant force to keep it there. Are you guys using joysticks with no centering springs? <Snipola> > I don't understand what non-force feedback joysticks you guys are using but > my MS stick is not force feedback and if I don't trim I have to move the > stick to a non-centered position which requires constant force to keep it > there. Are you guys using joysticks with no centering springs? Mirosoft Force Feedback 2. No springs. It has active servos powerful enough to whip the stick out of your hand. But that usually only happens on the third party aircraft I download that don't have the feedback design done right. On the default aircraft in MSFS the feedback can be strong and firm, but not violent. Brian Signaturehttp://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html Sed quis custodiet ipsos Custodes? > Depends on where you have the trim set which is always a compromise. If the > trim is set so that there is no nose down trimming required after takeoff, [quoted text clipped - 6 lines] > and since the airplane is accelerating, the trim is going to need to be > changed. I've been leaving the trim neutral. Rotation is sluggish up to a certain speed, then the plane pitches up rapidly if I try to rotate beyond that speed. Thereafter, I must push on the stick to keep the pitch angle within reason. I take it that I should trim to hold the nose down a bit? It just surprises me that the plane pitches up so quickly (particularly the Baron 58). If I know it's going to do this, I can adjust the stick as soon as the nose rises, but I was wondering if the real aircraft would behave in the same way. I don't see small planes taking off like that when I observe them from a distance. SignatureTranspose mxsmanic and gmail to reach me by e-mail. In both of the airplanes that I fly, I need to trim nose down after liftoff as the speed increases. You can see the same thing in a paper airplane. Make an airplane that will glide well, neither pitching down into a dive nor doing a series of pitch-ups and stalls. Then thow it hard. The harder you throw it the more it wants to pitch up. MSFS may or may not closely represent an actual B58 but the principle is correct. Whether neutral is the correct position for takeoff depends on CG. Jet aircraft have a trim position chard where the correct takeoff setting is given for a given CG location. On a twin where the props are blowing air across the wing and tail it also depends on how much power the engines are producing which is affected by altitude, temperature and mixture setting. Mike MU-2 >> Depends on where you have the trim set which is always a compromise. If >> the [quoted text clipped - 23 lines] > real aircraft would behave in the same way. I don't see small planes > taking off like that when I observe them from a distance. > In both of the airplanes that I fly, I need to trim nose down after liftoff > as the speed increases. [quoted text clipped - 10 lines] > across the wing and tail it also depends on how much power the engines are > producing which is affected by altitude, temperature and mixture setting. Unfortunately MSFS doesn't seem to provide much documentation on how to set the trim for each aircraft and situation (or I haven't found it). I guess I'll have to experiment. Fortunately trial and error is not dangerous in a sim. SignatureTranspose mxsmanic and gmail to reach me by e-mail. >> In both of the airplanes that I fly, I need to trim nose down after >> liftoff [quoted text clipped - 22 lines] > it). I guess I'll have to experiment. Fortunately trial and error is > not dangerous in a sim. That's because unless there is a specific marking (as there is for takeoff on the C172 both in RL and in FS9), there is no such thing as a specific way to set the trim for each situation. Trimming is a "feel" thing. You trim to relieve control pressures and you can't see pressure, you can only feel it. (I will conceed you can trim for straight and level because you can visually confirm that the VSI and ALT are steady for a given power setting.) Jay B > Trimming is a "feel" thing. You trim to relieve control pressures and > you can't see pressure, you can only feel it. Except in an airplane where the trim system moves the horizontal stabilizer instead of a trim tab. In that case, there is no feel feedback to the yoke. One must release the pressure and see if the airplane attitude remains where desired. Bob Moore > Except in an airplane where the trim system moves the horizontal > stabilizer instead of a trim tab. In that case, there is no feel > feedback to the yoke. One must release the pressure and see if the > airplane attitude remains where desired. Is that common? I note that there are slots in front of the stabilizers on a 737, implying that they pivot (for trim?). Is that in fact what they are doing? It's hard to see on the sim. SignatureTranspose mxsmanic and gmail to reach me by e-mail. >> Except in an airplane where the trim system moves the horizontal >> stabilizer instead of a trim tab. In that case, there is no feel >> feedback to the yoke. One must release the pressure and see if the >> airplane attitude remains where desired. > > Is that common? In jetliners...Yes > I note that there are slots in front of the stabilizers on a 737, > implying that they pivot (for trim?). Is that in fact what they are > doing? It's hard to see on the sim. Yes And, so far, no one has mentioned that in a jetliner, the main landing gear wheels are located far behind the aerodynamic center of rotation when the a/c is rotated for takeoff. If the a/c is trimmed for a low- force rotation, it will be out of trim for the initial climb. The initial trim setting for a jetliner must be computed for each takeoff based on the amount of load and its distribution. As I recall, the takeoff trim setting was for the V2+10 initial climb speed. Bob Moore ATP B-707 B-727 PanAm (retired) > Yes So aircraft that pivot the entire stabilizer also keep the entire travel of the elevator available for flight, right? Seems like a pretty bit advantage. If you use trim tabs, you sacrifice at least part of the elevator travel when you trim to a non-neutral setting; but if the whole stabilizer moves for trim, the entire travel of the elevator is still there for you to use. I wonder why smaller planes don't do this. Also ... why does a plane like the Baron 58 have a stick pusher? I presume you can't use it for instruction flights that teach about stalls, since it refuses to adopt an attitude that will cause a stall. > And, so far, no one has mentioned that in a jetliner, the main landing > gear wheels are located far behind the aerodynamic center of rotation [quoted text clipped - 4 lines] > takeoff based on the amount of load and its distribution. As I recall, > the takeoff trim setting was for the V2+10 initial climb speed. How do all these calculations get done? It seems like there are a lot of things that have to be calculated for every flight. Do pilots sit with calculators and do it, or do they have some less time-consuming way to cook up the necessary numbers? SignatureTranspose mxsmanic and gmail to reach me by e-mail. > So aircraft that pivot the entire stabilizer also keep the entire > travel of the elevator available for flight, right? Ah-Ha....you broke the code. :-) > I wonder why smaller planes don't do this. Generally speaking, they don't have as broad a cg range as a jetliner. > How do all these calculations get done? It seems like there are a lot > of things that have to be calculated for every flight. Do pilots sit > with calculators and do it, or do they have some less time-consuming > way to cook up the necessary numbers? Most airlines have a 'Load Control Center' with computers to do the work, but I have worked for small charter companies where the flight- crew (generally the copilot) works-up a Weight and Balance Form just prior to departing the gate since a copy must remain on file in operations. Bob Moore > Most airlines have a 'Load Control Center' with computers to do the > work, but I have worked for small charter companies where the flight- > crew (generally the copilot) works-up a Weight and Balance Form just > prior to departing the gate since a copy must remain on file in operations. I'm surprised large aircraft don't have a computer to do this on board, especially aircraft like the Scarebus, which already has a laptop game console for every crew member, it seems. SignatureTranspose mxsmanic and gmail to reach me by e-mail. . > Also ... why does a plane like the Baron 58 have a stick pusher? I > presume you can't use it for instruction flights that teach about > stalls, since it refuses to adopt an attitude that will cause a stall. Where did you read that a Baron 58 has a stick pusher? > Where did you read that a Baron 58 has a stick pusher? I didn't, but it has one in simulation, and I don't if it would be simulated if it didn't exist in real life. SignatureTranspose mxsmanic and gmail to reach me by e-mail. > Also ... why does a plane like the Baron 58 have a stick pusher? It doesn't, unless you are referring to the interface between the yoke and the seat cusion. SignaturePeter >> Also ... why does a plane like the Baron 58 have a stick pusher? > > It doesn't, unless you are referring to the interface between the yoke and > the seat cusion. Izzat the same device as the "nut holding the yoke?" <g d r> Jay B >>> Also ... why does a plane like the Baron 58 have a stick pusher? >> [quoted text clipped - 7 lines] > > Jay B Yokenut - I like that :) > Izzat the same device as the "nut holding the yoke?" 'xactly... SignaturePeter > It doesn't, unless you are referring to the interface between the yoke and > the seat cusion. It beeps and pitches forward in a stall in simulation. Simulators usually don't go to the time and expense of simulating something that isn't on the real aircraft. SignatureTranspose mxsmanic and gmail to reach me by e-mail. Mxsmanic, > It beeps and pitches forward in a stall in simulation. Man, you are not only clueless about instrument flying, but also about the simplest general principles of flying. What you're describing is the stall warning and the natural tendency of any aircraft in a stall to pitch down. SignatureThomas Borchert (EDDH) > Mxsmanic, > [quoted text clipped - 5 lines] > What you're describing is the stall warning and the natural tendency of > any aircraft in a stall to pitch down. He's always right and you're always wrong and his hours on MSFS count at least twice as your in your logbook. SignatureLeonard Milcin Jr. > What you're describing is the stall warning and the natural tendency of > any aircraft in a stall to pitch down. OK, the stall warning I can understand, but other aircraft don't pitch down abruptly like that. SignatureTranspose mxsmanic and gmail to reach me by e-mail. >> What you're describing is the stall warning and the natural tendency of >> any aircraft in a stall to pitch down. > > OK, the stall warning I can understand, but other aircraft don't pitch > down abruptly like that. I'm not a simmer but try pulling the left throttle to idle, right throttle wide open and then stall it :-) > I'm not a simmer but try pulling the left throttle to idle, right throttle > wide open and then stall it :-) Is this going to cause some sort of sim catastrophe? SignatureTranspose mxsmanic and gmail to reach me by e-mail. >> I'm not a simmer but try pulling the left throttle to idle, right >> throttle >> wide open and then stall it :-) > > Is this going to cause some sort of sim catastrophe? No, just an exciting ride :-) >>> I'm not a simmer but try pulling the left throttle to idle, right >>> throttle >>> wide open and then stall it :-) Ahhh, what the heck... Why not also push the left rudder pedal to the floor at the stall break? >> Is this going to cause some sort of sim catastrophe? > >No, just an exciting ride :-) Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com > No, just an exciting ride :-) I was unable to get the Baron to stall. A warning of some kind sounds and the aircraft pitches forward each time I try to stall it. Since I can't see the yoke in the sim, I don't know if the change in pitch is a result of a stall or some sort of automated attempt to prevent it, but in any case it's very irritating (although perhaps I'd be thankful for it in real life?). With one engine set to idle and pulling all the way back, the warning sounds, the aircraft bounces forward and backward, and it eventually meets the terrain in a rather lazy roll. SignatureTranspose mxsmanic and gmail to reach me by e-mail. "Mxsmanic" <mxsmanic@gmail.com> wrote in message > I was unable to get the Baron to stall. A warning of some kind sounds > and the aircraft pitches forward each time I try to stall it. What did you expect to happen when you stalled the airplane? > What did you expect to happen when you stalled the airplane? I expect it to lose altitude rapidly. Beyond that, it depends on the design of the aircraft. SignatureTranspose mxsmanic and gmail to reach me by e-mail. "Mxsmanic" <mxsmanic@gmail.com> wrote in message >> What did you expect to happen when you stalled the airplane? > > I expect it to lose altitude rapidly. Beyond that, it depends on the > design of the aircraft. Well, in the category of "beyond that", in light aircraft the rapid altitude loss is usually preceded and/or accompanied by an abrupt pitch down. One caveat: there may be some newer light craft designs that don't pitch too abruptly. I don't know about that. But in the great bulk of light aircraft, such as the Baron you were discussing, there will be a nose drop. I don't think you're dealing with a major design flaw in your sim program, perhaps just a question of degree or intensity. > Well, in the category of "beyond that", in light aircraft the rapid > altitude loss is usually preceded and/or accompanied by an abrupt pitch [quoted text clipped - 3 lines] > drop. I don't think you're dealing with a major design flaw in your sim > program, perhaps just a question of degree or intensity. As long as the sim is faithful to the real aircraft, I'll deal with it. I just want to make sure that it's not a sim artifact, as I don't want to build bad habits based on errors in simulation, just in case I ever actually do have an occasion to pilot a real aircraft. SignatureTranspose mxsmanic and gmail to reach me by e-mail. Allen, > I'm not a simmer but try pulling the left throttle to idle, right throttle > wide open and then stall it :-) Sims don't sim that very well. SignatureThomas Borchert (EDDH) > I wonder why smaller planes don't do this. Some do, Mooney, Cessna 180, 185 early 182 > Also ... why does a plane like the Baron 58 have a stick pusher? I Barons do not have a stick pusher. How do all these calculations get done?> Charts, graphs, calculators >> Yes > [quoted text clipped - 6 lines] > > I wonder why smaller planes don't do this. Because it is a tradeoff of cost, complexity and perhaps weight. Having a moving movable horizontal stabilizer allows the stabilizer and elevator to be in the same plane during cruise flight which reduces drag. A small airplane stabilator still has a trim tab which will usually be in a slightly different plane than the stabilator, producing added drag. The movable horizontal stabilizer is worth the tradeoff in a jet that flys long distances at high speed and has a wide cg range. It is also required at high mach numbers. Mike, > Because it is a tradeoff of cost, complexity and perhaps weight. But many do have that. The (older?) Mooneys even move the entire tail, IIRC. SignatureThomas Borchert (EDDH) > Mike, > >> Because it is a tradeoff of cost, complexity and perhaps weight. > > But many do have that. The (older?) Mooneys even move the entire tail, > IIRC. I have never seen a piston airplane with the system seen on jets. On jets, the entire horizontal stabilizer is moved with a jackscrew (trim) and the elevator is in the same plane as the horizontal stabilizer at any cg or speed. On a piston GA airplane with a stabilator, there is a trim tab on the stabilator which is not in the same plane as the stabilator except at one, unique trim setting. > I have never seen a piston airplane with the system seen on jets. On > jets, the entire horizontal stabilizer is moved with a jackscrew > (trim) and the elevator is in the same plane as the horizontal > stabilizer at any cg or speed. Ever see a Piper J-3 Cub ? Bob Moore I have, but have not noticed if it had a trimable stabilizer with a elevator. From your message, I assume that it does? >> I have never seen a piston airplane with the system seen on jets. On >> jets, the entire horizontal stabilizer is moved with a jackscrew [quoted text clipped - 4 lines] > > Bob Moore >I have, but have not noticed if it had a trimable stabilizer with a >elevator. From your message, I assume that it does? And the early Cessna 182 does also. >>> I have never seen a piston airplane with the system seen on jets. On >>> jets, the entire horizontal stabilizer is moved with a jackscrew [quoted text clipped - 4 lines] >> >> Bob Moore Bob, Can you explain that a little further? I don't see any difference in feel feedback between a Cessna 182 (trim tab) and 185 (stab trim). Why should there be a difference? Karl "Curator" N185KG >> Trimming is a "feel" thing. You trim to relieve control pressures and >> you can't see pressure, you can only feel it. [quoted text clipped - 5 lines] > > Bob Moore > Bob, > Can you explain that a little further? I don't see any difference in > feel feedback between a Cessna 182 (trim tab) and 185 (stab trim). Why > should there be a difference? Karl, I have no experience with in the smaller a/c, but as a Boeing instructor (B-707, B-727), it took a good amount of time to teach a new jet pilot how to trim because of this effect. If from level flight, you want to raise the nose for a climb, you pull back and obviously feel the back pressure from the elevator being displaced relative to the stabilizer, at this point, trimming just changes the stabilizer position without putting the elevator in a new position relative to the stabilizer and releiving the pressure. Large trim changes (as in a go-around) consisted of a large number of trim/release cycles in order to find the exact amount required. Bob Moore Hi Bob, Just curious: do the old-school Boeings not have Artificial Feel Units? SignatureMichael Nouak remove "nospamfor" to reply: nospamformakn@chello.at >> Bob, >> Can you explain that a little further? I don't see any difference in [quoted text clipped - 16 lines] > > Bob Moore > Just curious: do the old-school Boeings not have Artificial Feel Units? On the hydraulicly powered rudder...yes, cable operated aileron servo tabs...No, Cable operated elevator servo tabs.....No. Bob > Except in an airplane where the trim system moves the horizontal > stabilizer instead of a trim tab. In that case, there is no feel > feedback to the yoke. One must release the pressure and see if the > airplane attitude remains where desired. This makes no sense to me. If the airplane attitude remains "where desired" (I presume that is the same as where you put it, using pressure) when you release the pressure, then the pressure isn't doing anything. How do you fly such an aircraft? Jose SignatureThere are more ways to skin a cat than there are cats. for Email, make the obvious change in the address. "Jose" <teacherjh@aol.nojunk.com> wrote in message news:1MzNg.443> > This makes no sense to me. If the airplane attitude remains "where > desired" (I presume that is the same as where you put it, using pressure) > when you release the pressure, then the pressure isn't doing anything. > How do you fly such an aircraft? The way I look at it is that you have to use a different combination of sensory data than if you were flying a small aircraft with direct cable controls and elevator trim. In the 727, my recollection is that there is not a complete lack of feedback feeling; there is a little, but it is different from flying traditional trim tabs. On the 727 (and, I presume, on the 707) you have a movable stabilizer, an elevator, and elevator trim tabs. The elevator trim tabs are locked out of the trim system as long as the electric stab trim motors are functional. When locked out, they function as balance tabs. There is an elevator feel computer in the 727 whose main purpose is not to provide yoke force feedback, but it does give some little feeling to the yoke as a side effect. The bottom line, at least in my perception, is that with some experience in the aircraft you can become very adept at simultaneously positioning your attitude, and adjusting the trim so you don't have to keep positioning your attitude. Of course, as the craft accelerates or decelerates you have to repeat the process as configuration and speed change. As a practical matter, you are [almost] flying with the stab trim. > This makes no sense to me. Yes Jose, we do understand that a lot of things make no sense to you. > If the airplane attitude remains "where desired" > (I presume that is the same as where you put it, using > pressure) when you release the pressure, then the pressure isn't > doing anything. How do you fly such an aircraft? First.....Put the nose where desired and feel pressure on the yoke. Second....Start trimming, airliners generally use electric trim. Third.....Stop trimming....release pressure on yoke Fourth....Check nose position, if it stays where you put it, you did the correct amount of trimming, if not, repeat the procedure as many times as required. Fifth.....If all else fails, turn on the autopilot and let it trim. Actually, on the older Boeings that I flew, the pilot could do a better job of trimming than the autopilot since the autopilot did not mind holding a little pressure forever. Only when the elevator became some number of units out of alignment with the stabilizer did the autopilot kick in the stabilizer trim system. It was common that when flying on autopilot,if a pilot observed on the control surface deflection indicators that the autopilot was actually holding some 'up' elevator, he would use the manual trim wheel to fair the elevator and stabilizer and reduce the 'trim drag' which could consume a lot of fuel. Bob Moore > Third.....Stop trimming....release pressure on yoke Are you maintaining pressure on the yoke as you trim? IN the spam cans I fly, I am relaxing pressure and keeping the position of the nose constant. When I'm out of pressure, I stop trimming. Now I don't fly jetliners but the physics is the same, no? Jose SignatureThere are more ways to skin a cat than there are cats. for Email, make the obvious change in the address. > Are you maintaining pressure on the yoke as you trim? IN the spam cans > I fly, I am relaxing pressure and keeping the position of the nose > constant. When I'm out of pressure, I stop trimming. Now I don't fly > jetliners but the physics is the same, no? Nope! If you are holding say...5 pounds of pressure and you electrically trim for 10-15 seconds, you will still feel the same pressure. As I said, teaching a new student to trim an early Boeing was a real chore. Bob Moore >> Now I don't fly >> jetliners but the physics is the same, no? > Nope! If you are holding say...5 pounds of pressure and you electrically > trim for 10-15 seconds, you will still feel the same pressure. Ok, then what happens if you electronically trim for the "right" amount of time. You still feel some pressure but you are in trim. You release the pressure and the nose stays in the same position. NOW you apply the exact same pressure you had before you released. Does the nose go up? Why? What happened in the interim? Jose SignatureThere are more ways to skin a cat than there are cats. for Email, make the obvious change in the address. >> Third.....Stop trimming....release pressure on yoke > > Are you maintaining pressure on the yoke as you trim? IN the spam cans I > fly, I am relaxing pressure and keeping the position of the nose constant. > When I'm out of pressure, I stop trimming. Now I don't fly jetliners but > the physics is the same, no? You are both describing the same action, Bob should have just said "release the yoke" if the nose stays where you want it you are trimmed. : ) > You are both describing the same action, Bob should have just said "release > the yoke" if the nose stays where you want it you are trimmed. : ) Well, that's not the way I read the original post that raised my question, and prompted Jay Beckman's comment that there is a lot that makes no sense to me: >> [Jay Beckman:] Trimming is a "feel" thing. You trim to relieve control pressures and >> you can't see pressure, you can only feel it. [quoted text clipped - 3 lines] > feedback to the yoke. One must release the pressure and see if the > airplane attitude remains where desired. From this I gather that there is no difference in pressure on the yoke when you are trimmed vs untrimmed. "One must release the pressure and see..." Is the pressure so light that one flies much like a non-force-feedback simulator? This would be very weird for me. I'm used to flying real airplanes, not giant tubes with wings on them. :) Jose SignatureThere are more ways to skin a cat than there are cats. for Email, make the obvious change in the address. >> You are both describing the same action, Bob should have just said >> "release the yoke" if the nose stays where you want it you are trimmed. [quoted text clipped - 21 lines] > > Jose I got the impression from Bob's post that, in the case he describes, you are (effectively) always trimmed. IOW, it will stay nose up, nose down, right where it is ... but you have to do some trial and error tweaking to ensure sure you are trimmed for the attitude you *want* ... Am I close, Bob? Jay B > I got the impression from Bob's post that, in the case he describes, you are > (effectively) always trimmed. If this is the case, then what "pressure" are you releasing? Jose SignatureThere are more ways to skin a cat than there are cats. for Email, make the obvious change in the address. >> You are both describing the same action, Bob should have just said >> "release the yoke" if the nose stays where you want it you are trimmed. [quoted text clipped - 21 lines] > > Jose I have flown C182 with the horizontal stabilizer trim and with the elevator trim. Both felt the same to me. I have also flown a Lear 35 with horizontal stabilizer trim. It felt the same as the C182 in regards to trim inputs. > Actually, on the older Boeings that I flew, the pilot could do a > better job of trimming than the autopilot since the autopilot did > not mind holding a little pressure forever That is true of the S-Tec 60-2 autopilot in my Bonanza, too. At the top of climb and upon selecting the ALT hold as the aircraft's speed increases, the AP will keep the aircraft level all while fighting a slight nose up trim. Disengage the AP and the aircraft will immediately nose up a few degrees if the pilot is unprepared (i.e. improper pressure in the yoke). I have learned to first allow the aircraft's speed to stabilize and then disengage the AP to manually retrim for level flight before re-engaging the AP. Having all that tension in the system just doesn't seem right to me. SignaturePeter Do you have Autotrim in your Bo? > > Actually, on the older Boeings that I flew, the pilot could do a > > better job of trimming than the autopilot since the autopilot did [quoted text clipped - 9 lines] > disengage the AP to manually retrim for level flight before re-engaging the > AP. Having all that tension in the system just doesn't seem right to me. > Do you have Autotrim in your Bo? Yes. SignaturePeter From the Sys 60-2 POH: "If the autopilot is equipped with optional Autotrim, the aircraft elevator trim will be maintained automatically when the Trim Master Switch is ON and a pitch mode is activated. When the Trim Master Switch is ON, the trim annunciators are disabled. If the switch is OFF, or a power failure occurs, the annunciators automatically become functional." Does it not function this way? > > Do you have Autotrim in your Bo? > > Yes. > From the Sys 60-2 POH: > [quoted text clipped - 6 lines] > > Does it not function this way? It does, but it appears to require an adjustment. I had mentioned this squawk at one time to an avionics tech who then admitted that there is an adjustment to the autotrim, but he gave me the impression that it was not an exact science. Since I had incorporated a work-around into my cruise checklist, I decided to put this adjustment on the low priority list. Do you also fly with the 60-2? I had been thinking about adding the yaw damper option, but other things like starters, alternators, and my Garmin GNS430 keep breaking just out of warranty and demanding the attention of the checkbook. SignaturePeter No, I'm still a ground-bound wannabe, working slowly toward a Sport Pilot ticket. But I try to pay attention to stuff, and I've learned a lot from a lot of sources, and I find that most of the people here are willing to answer questions... > > From the Sys 60-2 POH: > > [quoted text clipped - 17 lines] > GNS430 keep breaking just out of warranty and demanding the attention of > the checkbook. > That's because unless there is a specific marking (as there is for takeoff > on the C172 both in RL and in FS9), there is no such thing as a specific way > to set the trim for each situation. > > Trimming is a "feel" thing. You trim to relieve control pressures and you > can't see pressure, you can only feel it. But if you have an unusual load aboard, it would seem that you wouldn't be able to feel it until you're already in the air. Unless you mean that you'd be able to extrapolate from previous experience with other loads. > I will conceed you can trim for straight and level because you can visually > confirm that the VSI and ALT are steady for a given power setting. I'd just like to be able to rotate more smoothly. I had to modify the contact points on the 737 just because I was plowing the tail into the runway on take-off (and the standard model doesn't take any note of this, which meant I was cheating for a long time and didn't realize it). The B58 pitches upward even more quickly. I think if I can get good at putting the stick forward in just the right way as the nose rises I will be able to rotate smoothly, eventually, but I will try the trim stuff. SignatureTranspose mxsmanic and gmail to reach me by e-mail. >> That's because unless there is a specific marking (as there is for >> takeoff [quoted text clipped - 10 lines] > you mean that you'd be able to extrapolate from previous experience > with other loads. Define "Unusual Load." ??? If you are way over MGW or loaded well aft of the CG limit, you're already in a very dangerous place and no amount of trim will help. > I'd just like to be able to rotate more smoothly. Don't pull so hard... Seriously, for most GA aircraft, when you reach Vr, you pull just enough to set an attitude and let the plane do the work. It sounds like the dynamics of flying "heavy iron" are a little different due to the placement of the mains versus the CG/CL but it can't be all THAT different. >I had to modify the contact points on the 737 just because I was plowing >the tail into the runway on take-off (and the standard model doesn't take >any note of this, which meant I was cheating for a long >time and didn't >realize it). The B58 pitches upward even more quickly. Your simply being too aggressive and over rotating. >I think if I can get good at putting the stick forward in just the right >way as the nose rises I will be able to rotate smoothly, eventually, but I >will try the trim stuff. Like I said, don't try to horse the plane off the ground...set a proper attitude at rotation and let the plane fly itself off the ground. Once you are airborne and accelerating, then you can worry about pitch and power to acheive a specific airspeed (Vx, Vy, etc...) Jay Beckman PP-ASEL Chandler, AZ > Define "Unusual Load." ??? One that creates a potential safety hazard, or at least requires some specific and prompt action. It might still be within specs but would be unusual enough to come as a nasty surprise if one were not prepared for it. > Don't pull so hard... I have to pull quite a bit to get the nose up--but then it continues to rise rapidly on its own, so I have to push the stick forward again to avoid a tail strike. > Seriously, for most GA aircraft, when you reach Vr, you pull just enough to > set an attitude and let the plane do the work. It sounds like the dynamics > of flying "heavy iron" are a little different due to the placement of the > mains versus the CG/CL but it can't be all THAT different. The 737 rotates more slowly, so you have more time to keep it from rotating too far. I had to fly it from both the outside and inside for a while to see how far it could rotate, since I couldn't find any documentation on the exact numbers to use. > Your simply being too aggressive and over rotating. Maybe I'm rotating at the wrong time, or the stick's in the wrong place to begin with when I start rolling. Suggestions are welcome. I've tried pulling the stick slightly so that the aircraft would rotate on its own when it "felt" it was going fast enough. I've tried keeping the stick forward so that it doesn't rotate until it's actually rolling well faster than Vr. It may be that the Baron is very heavily loaded by default in MSFS. If I just put myself in the cockpit it might behave better, so I will try that as well. > Like I said, don't try to horse the plane off the ground...set a proper > attitude at rotation and let the plane fly itself off the ground. Once you > are airborne and accelerating, then you can worry about pitch and power to > acheive a specific airspeed (Vx, Vy, etc...) That's what I've been trying, but I don't seem to be very good at it. I'll continue to practice. SignatureTranspose mxsmanic and gmail to reach me by e-mail. >> That's what I've been trying, but I don't seem to be very good at it. > I'll continue to practice. Mx you are playing a computer game and not playing it very well from the sound of it. If you want it to be more than a game for you go find one of many books that are out there for private pilot ground school. "Mxsmanic" <mxsmanic@gmail.com> wrote in message > Do real aircraft abruptly pitch upward on take-off during rotation, > Large jets seem to do the same thing, but at a slower speed. Almost every aircraft I've flown has required nose down trim after takeoff. Not abruptly, not drastically, but promptly after takeoff, as the craft accelerates and you transition to climb, you always have to trim it down. > Almost every aircraft I've flown has required nose down trim after takeoff. > Not abruptly, not drastically, but promptly after takeoff, as the craft > accelerates and you transition to climb, you always have to trim it down. I'll try this. In the past, I haven't used trim much. SignatureTranspose mxsmanic and gmail to reach me by e-mail. IMHO, but as one who has both flown (limited and novice only) but has teased myself with the majority of the $MS flight sims.... the sim is ONLY an approximation given a set a dynamic variables. It is NOT a true professional flight simulator on a hydraulic motion platform with millions of dollars of electrical and mechanical equipment. Yes, the game breed FS's come close in appreciating the flight dynamics such as stall speeds and standard turns etc. .. and is is good for IFR practice in principle only.... but the PC based flight sims do not have any real world body senses incorporated... which at least for me changes everything. Tor theory PC FS training its fine... but not real world by any means. It will help in a person's real flight training, but only in thorectical knowledge of what to expect. Example: When I was doing my PP license training... the flight instructor started the first of the "unusual attitude recovery" training... where after blocking outside visual reference she (in my case) played around with the airplane's attitude (pitch and bank) a while... and then hands it to you to recover on instruments only. Me being me with zillions of hours on all types of farm and industrial equipment... where my butt and ears plug in directly to any piece of equipment... I followed along with her attitude adjustments quite easily and had a fairly good idea just where she'd left it (changes were too abrupt for fooling the inner ear, and I know engine loads). All I had to do was verify what my body and senses had indicated with the instruments, which was practically instantaneous due to my FS time. So yes there is an advantage to the game FSs... but it is limited. (BTW, She'd left it in a 20 degree left bank, 20 degree nose down and idle. Since I'd already had about 40 hours in a Eipper MX UL and had some stick time (ok yoke) in another 152, I was not afraid of full deflection in a 152.. . I simultaneously applied full power, full right, 3/4 back, and full right rudder, instantaneously snapping her back to straight and level and neutralizing... then minor tweaks to regulate to cruise, heading, and back in trim. All she said was "WOW!".... I said ... "Lets do that again!", "That was fun"... I still smile at the memory) Dave M |
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