AIRCRAFT CONF

[727 driver]

HOpe SOMEONE can help..i do pritty well in the aircraft config..tweeked many planes..but i do have a question..when flyng a jet whe lets say you bank to the left at say 20 deg. i notice on some planes( large jets)  have a tendency to roll back to level flight..i know this stability is built into small single aircraft such as real world cessna and piper aircraft.. (as i fly both as a private pilot) but dont know how true it is in large jet aircraft..does anyone know how to take that tendincy out of the large jets??i want to bank the plane and have it stay there..so i bank to 20 deg. and 20 is where it will stay..can this be done through the aircraft conf.thank you all in advanced for takeing the time to reply..

[Boikat]

Not that I know of.  That does not mean it can't be done, just that I wouldn't know how to do it if it can be done.

[727 driver]

im thinking its in the air file which i havent touched..because i wouldent have a clue as to what to do ,and it would seem there are not many people who know how to do this ...so the search goes on...thanks for the post though..happy landings..[quote]Not that I know of.

[gypsymoth]

Maybe I've not understood your question?  When I bank using my stick the aircraft stays there until I let go, when it will then flatten out.   The other way is with altitude in the autopilot & a heading - that will give 20 deg bank, & level flight occurs when the heading is turned off.    I'm not sure how  changing a cfg will do what you want.    

[727 driver]

THE 777 is fly by wire.as is many others 757 767when a pilot banks the plane lets say 20 degrees he does not have to hold any left pressure at all.the aircraft will stay at 20 degrees untill the pilot inputs right control..on the sim some jets when displaced to the right or left they have a tendency to  return to 0 bank angle on there own...in small aircraft like a cessna or piper trainer..this is normal..that stability is built into them..in a jet its not the case..at least not fly by wire jets..but the good news here is i figured it out and got my 777 and 757 300 banking and staying there...found it was in the aircraft config after all...its kinda a balanceing act between roll stability numbers and aileron effectiveness numbers..[quote]Maybe I've not understood your question?

[beaky]

Perhaps the autopilot is on? Stupid question, I know, but it wouldn't be the first time.

[727 driver]

good point rottydaddy..but the A/P is off...that would do though as you know..i got it figuered out at this point.

Perhaps the autopilot is on? Stupid question, I know, but it wouldn't be the first time.

[gypsymoth]

Ahh - the old fly by wire!     What did you change by the way?

[727 driver]

ail effectiveness and roll stab..and now iv got both planes 777 and my 757 300 flying awsum..the 757 300 was tweeked by me but i had a 757 300 pilot here..(an ole friend)..he flew it told me that it was right or not right.we did this for 3 hours ....each control..throughout the speed range ..at the end of the day he said it was 95%+ real feel..of corse we will never get 100% due to the restrictions of fs..but ill take 95%  :) happely..[quote]Ahh - the old fly by wire!

[Nav]

[quote]THE 777 is fly by wire.as is many others 757 767when a pilot banks the plane lets say 20 degrees he does not have to hold any left pressure at all.the aircraft will stay at 20 degrees untill the pilot inputs right control..on the sim some jets when displaced to the right or left they have a tendency to

[Hagar]

THE 777 is fly by wire.as is many others 757 767when a pilot banks the plane lets say 20 degrees he does not have to hold any left pressure at all.the aircraft will stay at 20 degrees untill the pilot inputs right control..on the sim some jets when displaced to the right or left they have a tendency to  return to 0 bank angle on there own...

Not quite correct, 727 driver.

'Fly by wire' only refers to the way that the pilot's commands are transmitted to the control surfaces; by electric current and motors instead of via cables and linkages.

The term "fly-by-wire" is generally used these days for digital systems where the control input is directed to the control surfaces via a computer. It would be very difficult for a pilot to control an aircraft without some sort of "artificial feel" even if this was a simple spring self-centring mechanism as used on the typical gaming joystick. (This was discovered on the prototype YF-16 where the sidestick did not actually move at all.) I've never flown a fly-by-wire aircraft but I imagine FS with a standard gaming joystick gives a pretty fair idea of what it's like. The same applies to a radio controlled model aircraft.

Again, I'm not sure of my facts regarding the 777 but I would expect any modern jet airliner to have inherent lateral stability. Positive dihedral on any aircraft will make it laterally stable. This would give it a natural tendency to right itself when the controls are centralised. The more dihedral the more stable it will be. [url]http://www.centennialofflight.gov/essay/Theories_of_Flight/Stability_II/TH27G8.htm
[/url]

Now look at the dihedral on the 777.

[727 driver]

the info i got from a 777 pilot was in fact when you bank the 777 it stays there until you bring it back..this is what was sent to me via email by a 777 captain about the subject and he writes........Because the 777 uses a fly-by-wire system, we put the control column back to neutral once we have the desired angle of bank. The plane will stay exactly where it is until you put in a new input. end quote..i asked him for the answer because i no clue how a 777 should feel in flight .this 777 captain who shoots videos for you tube..so respectfuly

[Nav]

It would be very difficult for a pilot to control an aircraft without some sort of "artificial feel" even if this was a simple spring self-centring mechanism as used on the typical gaming joystick. (This was discovered on the prototype YF-16 where the sidestick did not actually move at all.) I've never flown a fly-by-wire aircraft but I imagine FS with a standard gaming joystick gives a pretty fair idea of what it's like.

Agree entirely about the difficulty, Hagar. But, as far as I know, there is no feedback at all on the Airbus sidestick, except for the centring spring. Furthermore, movement of the control surfaces (ailerons, rudder, and elevators) is 'auto-coordinated' - the system assumes that if you apply say left bank, you want to make a coordinated turn left, and uses the other controls (elevators and rudder) as necessary to carry out a stable turn.

Said auto-coordination can't be turned off, either. For this reason the Airbus FCOMs say that, when dealing with crosswinds, pilots should use crabbing only for the approach, and only use 'crossed controls' to line up with the centreline in the last few moments before touchdown - otherwise the 'systems' tend to get confused.........

[727 driver]

AWSUM SITE ..nav 2 questions,,do you know of a site that gives that kind of info for the 757 300 and the 777 200..reading info that airline pilots post is the most intresting to me..but my search has not came up with anything that came close to yours..and the other question do you know if the a300 b4 a300 600 uses the same systems posted at the site you gave us or is that more a less older tech to your knowledge ..

It would be very difficult for a pilot to control an aircraft without some sort of "artificial feel" even if this was a simple spring self-centring mechanism as used on the typical gaming joystick. (This was discovered on the prototype YF-16 where the sidestick did not actually move at all.) I've never flown a fly-by-wire aircraft but I imagine FS with a standard gaming joystick gives a pretty fair idea of what it's like.

Agree entirely about the difficulty, Hagar. But, as far as I know, there is no feedback at all on the Airbus sidestick, except for the centring spring. Furthermore, movement of the control surfaces (ailerons, rudder, and elevators) is 'auto-coordinated' - the system assumes that if you apply say left bank, you want to make a coordinated turn left, and uses the other controls (elevators and rudder) as necessary to carry out a stable turn.

Said auto-coordination can't be turned off, either. For this reason the Airbus FCOMs say that, when dealing with crosswinds, pilots should use crabbing only for the approach, and only use 'crossed controls' to line up with the centreline in the last few moments before touchdown - otherwise the 'systems' tend to get confused.........

[Nav]

nav 2 questions,,do you know of a site that gives that kind of info for the 757 300 and the 777 200..reading info that airline pilots post is the most intresting to me..but my search has not came up with anything that came close to yours..and the other question do you know if the a300 b4 a300 600 uses the same systems posted at the site you gave us or is that more a less older tech to your knowledge ..

You're on the right track with the A300/310, 727 driver, they had conventional yokes and linkages, they were 'pre-fly-by-wire.' The first FBW Airbus (with, as Hagar says, added 'pilot-calming' measures applied by way of a computer interposed between the controls and the the control surfaces) was the A320.

Trouble is, it's a huge subject (probably outside the scope of a 'hobby' site). I don't know of any 'how-to-do' sites about Boeings, but they're not really necessary as Boeing's design philosophy is firstly to build in 'control feel,' and secondly to leave the final say with the pilot. So they fly much like any other aeroplane.

Best example of the difference between the two types that I can think of is that, in a Boeing, if the pilot pulls the nose up too much for a given speed and power setting, the 'system' will let him do it - but there'll be all sorts of stall warnings, like a 'stick shaker' and klaxons and flashing lights. In an Airbus the 'systems' will overrule the pilot and simply trim the nose down to a safe angle, regardless of how hard the pilot 'pulls back.'

My own impression (also from talking to pilots) is that the Airbus is very easy to fly in 'normal' conditions (very 'point and shoot,' whereas the Boeing requires more physical effort and 'seat of the pants'); but that in difficult conditions the Airbus is 'tricky' (mainly because of the lack of 'feel' and the delayed responses), and therefore the Boeing has the edge.

To me, one of the key areas is 'crossing the controls.' Pleased to say that you can 'read all about that' on here if you like :-

http://www.simviation.com/cgi-bin/yabb2/YaBB.pl?board=COF;action=display;num=1129643666

The Airbus A320 Flight Crew Operating Manual says this about crosswind landings:-

"Before flare height, heading corrections should only be made with roll. As small bank angles are possible and acceptable close to the ground, only small heading changes can be envisaged. Otherwise, a go-around should be initiated.

"Use of rudder, combined with roll inputs, should be avoided, since this may significantly increase the pilot's lateral handling tasks. Rudder use should be limited to the "de-crab" maneuver in case of crosswind, while maintaining the wings level with the sidestick in the roll axis."

One part of that is plain wrong, IMO - I was always taught that in a stiff crosswind you shouldn't land with the 'wings level'; you should drop the upwind wing enough to make sure that the wind doesn't get under it and the upwind wheel touches down first. Easy to do in most aeroplanes because you can apply roll and rudder in opposite directions at any time - but apparently you can't do that in an Airbus until the very last moment, because this may "significantly increase the pilot's lateral handling tasks."

So that business of only straightening out at the last minute worries me. Purely my own opinion, there's been no Accident Report yet; but I can't help wondering if it was uncoordinated and/or excessive last-minute use of sidestick and rudder that caused this recent incident at Hamburg:-

http://www.youtube.com/watch?v=hAl1IJYx0C8