Aileron & Rudder

[Will273 23]

I want to see if real world flying in GA aircraft is like in simulation. Many GA aircraft I have want to roll to the left so I need to add a bit of right aileron and bit of rudder to get straight and level but I have to keep a little pressure on the stick and rudder to stay straight and level unless I trim the elevator and aileron. I'm aware some aircraft in the real world don't have aileron or rudder trim so if they have to keep a bit of constant pressure on the stick and rudder would they be able to do hands off straight and level flight and does hands off mean feet off rudder too? My big question is if it's normal to keep a little constant pressure on the stick and rudder if it's not trimmed? I can trim the elevator to keep a level altitude but not sure about straight flight if the aircraft doesn't have aileron and rudder trim...how does that work?

[John_Cillis 2,406]

12 minutes ago, Will273 said:

I want to see if real world flying in GA aircraft is like in simulation. Many GA aircraft I have want to roll to the left so I need to add a bit of right aileron and bit of rudder to get straight and level but I have to keep a little pressure on the stick and rudder to stay straight and level unless I trim the elevator and aileron. I'm aware some aircraft in the real world don't have aileron or rudder trim so if they have to keep a bit of constant pressure on the stick and rudder would they be able to do hands off straight and level flight and does hands off mean feet off rudder too? My big question is if it's normal to keep a little constant pressure on the stick and rudder if it's not trimmed? I can trim the elevator to keep a level altitude but not sure about straight flight if the aircraft doesn't have aileron and rudder trim...how does that work?

When I took training in an Allegro 2000 I had to counter some yaw with just light rudder, depends on the aircraft and how much rudder authority the aircraft has.  In climbs some rudder is needed and in descents opposite rudder is needed, not much however, just touches of it, again depending on the aircraft and also where the horz stab is as well.  I have flown both Ttail and aircraft with the stab in the standard location, slightly different rudder needs for both.  In turns just a little rudder is needed to coordinate the turn, the bank angle is what really turns the airplane, as I learned early on constantly I was coached "the wings turn the aircraft".  On landing touches of rudder may be used, but too much rudder is hard on the aircraft, as evidenced by the JFK crash years back where too much rudder was used to counter wake turbulence.  Seat of the pants learning is great for learning rudder use so your eyes do not follow the ball in the turn coordinator, it is bad to get focussed on the instrument scan ins the aircraft "LOOK OUTSIDE" as my CFI coached this simmer trying to apply poor cockpit drill learning from my sim use.  He said sim use taught me well how to handle the aircraft in flight, the basics you know, i was not sharp at landing, was not use to the yawing of the aircraft due to chop and variable winds.

John

Edited August 19, 2018 by Cactus521

[Chock 17,769]

Many aeroplanes without adjustable trim tabs have preset tabs, often these are as simple as literally a metal tab on the trailing edge of a control surface which can be bent by hand when on the ground to be 'adjusted' prior to your flight. Others have asymmetric control surfaces which are designed to imbue straight flight at cruise speed, the Messerschmitt bf 109 has a rudder like that for example, it is very obviously not symmetrical when you look at it closely.

[Will273 23]

Thanks John. Well if the plane starts turning left I can use just  wee touch of left rudder and it straightens out but if I use more than a wee touch and I mean a hairs width more the plane will turn to the left even more...does that sound right? I also have to keep constant wee tiny pressure on the stick/aileron and rudder through the whole flight...is that normal too...I'm not talking about a little here and a little there...I'm talking about the whole flight from takeoff to touchdown. I bought a new stick and recalibrated everything and this is what's happening so I'd like to know if that sounds right. Constant little pressure...normal? Thanks again.

[Oracle427 45]

If you are asking if an airplane without an autopilot can be flown "hands free" the answer is no. Regular input is going to be required by the pilot to maintain attitude, altitude and course. Generally speaking the trim will make the airplane fly coordinated or hold a general pitch setting, but you can't set it up so that you can let go of the controls for more than several seconds to a minute depending on the conditions you are flying in, even in totally smooth air. I regularly fly a 172 and two different 182s and while each handles a little different from the other, they all demand constant attention from the pilot from the moment you turn that engine on until the moment you shut it off and tie it down. Every other type of piston powered single I have flown is the same way.

[John_Cillis 2,406]

2 hours ago, Will273 said:

Thanks John. Well if the plane starts turning left I can use just  wee touch of left rudder and it straightens out but if I use more than a wee touch and I mean a hairs width more the plane will turn to the left even more...does that sound right? I also have to keep constant wee tiny pressure on the stick/aileron and rudder through the whole flight...is that normal too...I'm not talking about a little here and a little there...I'm talking about the whole flight from takeoff to touchdown. I bought a new stick and recalibrated everything and this is what's happening so I'd like to know if that sounds right. Constant little pressure...normal? Thanks again.

Good replies here all with the same insight as mine.  The rudder can be very touchy, the best aircraft I ever flew and almost bought was a Luscombe Taildragger, it had such well harmonized controls in the sky even with variable winds and a storm moving in I felt like I was flying on a sheet of glass and the owner commented on how comfortable I felt, he only took the aircraft for landing since there was a 50 foot stand of trees at the end of the grass runway in Penn.  I found the rudder most helpful on landing, to keep the aircraft going right toward the centerline without drifting left or right, just a harmony with it, no stress, let me fly the aircraft instead of letting the aircraft fly me.

 

Then I switched to Trikes, no more rudder to worry about, the human is the hydraulics or fly by wire whatever you want to call it.  If I ever buy an aircraft it will be a single place ultralight trike.

John

[Will273 23]

Thanks guys. I mentioned trim not the autopilot but it doesn't matter...they're close enough. Oracle...I don't mean to be splitting hairs here but when you said "regular input" is that the same as "constant input" meaning your hands/feet stay on the stick/rudder applying a light touch of "constant" pressure....like a human trim tab...which is what I'm having to do. If I take my hands/feet off the controls for a couple seconds then the plane will start rolling. May as well throw this in too while we're at it...so where and how does hands off straight and level flight come into play here...are they using their feet on the rudder? I've seen videos of this but rudder is never mentioned. I assumed hands off meant feet off too but maybe I'm wrong here. Sorry for all the questions.

[skelsey 765]

33 minutes ago, Will273 said:

when you said "regular input" is that the same as "constant input" meaning your hands/feet stay on the stick/rudder applying a light touch of "constant" pressure

Yep, for sure. Quite apart from the aerodynamic considerations, there are numerous factors that can cause a light aeroplane in particular to fly slightly wonky in the way you describe, from load distribution (e.g. if you are solo vs rather than having someone sat next to you) through to slight misrigging of the control cables, imperfections in the manufacturing of the airframe/a slightly bent airframe etc etc.

Aerodynamically, slipstream from the propeller has a major influence: when power is increased the slipstream will tend to strike the left hand side of the fin and cause a yaw to the left, which requires right rudder pressure to balance. Conversely a power reduction must be balanced with a left rudder input. It also follows that the aeroplane will only be balanced without the need for corrective rudder at one particular airspeed/power setting: commonly the rudder will be designed and/or have a ground-adjustable tab as described by Alan set for a typical cruise setting but again it is an imperfect science.

Edit to add: in a real aircraft one might wedge one's knee against the stick etc to keep it in place whilst wrestling with a chart, but obviously most of us don't have floor mounted sticks in the sim world!

Apply rudder pressure to keep the ball in the middle. If the aeroplane is rolling left, left rudder will exacerbate that problem, not fix it, so I'm a little confused there?

[Oracle427 45]

I would interpret hands off as, "You are not applying a constant control force to maintain the desired aircraft attitude". So if you are applying a constant pressure to keep the aircraft in some attitude, whether it be straight and level or in a constant speed climb or descent, then something is out of trim.

The thing is that with the control systems these light GA aircraft have, you aren't getting much feedback in the roll axis through the yoke. You would certainly be applying some force in the pitch are yaw axis. The ailerons generally don't feel much heavier as you input more roll on the yoke or stick. They will feel heavier as your airspeed increases and feel very light at low airspeeds. It isn't uncommon to find the yoke or stick commanding a very slight input to one side or the other. This could be a function of the slipstream, torque, fuel imbalance or even rigging of the aircraft.

Our joysticks are unfortunately unable to mimic this at all. You might need to hold the most gently pressure on the stick to counter this tendency, while in the real aircraft, the yoke or stick will generally remain wherever you command the ailerons to be. Keep in mind that this is true for all aircraft, but has been for the majority of the types I have flown. You wouldn't notice that you are holding ever so slight a roll input.

I would strongly recommend taking out all the dead/null zone on your controls if you have any as this will reduce the magnitude of the input you must make. It will more closely reflect the real behavior.

I raised autopilot as this is the only tool that will get you "true" hands off flight.

Edited August 20, 2018 by Oracle427

[Will273 23]

I'm confused myself. I'm hearing from a few people to use rudder to fix a roll but don't say much about aileron. When the aircraft starts to roll left I can use a wee bit of left rudder to bring it back but I also need a touch of right aileron too...actually both and I have to keep both applied to keep the ball centered. I can use right aileron to correct it too but have to keep nudging it to the right or steady pressure on both rudder/aileron at all times. It all starts from takeoff until landing. If I use to much left rudder to correct a left roll then I go into a steeper left roll so right aileron is needed.

I recalibrated my stick and it still did it...even bought a new stick and it still does it. Also thought it might be a fuel or weight imbalance but doesn't look like it.

[Will273 23]

27 minutes ago, Oracle427 said:

I would interpret hands off as, "You are not applying a constant control force to maintain the desired aircraft attitude". So if you are applying a constant pressure to keep the aircraft in some attitude, whether it be straight and level or in a constant speed climb or descent, then something is out of trim.

The thing is that with the control systems these light GA aircraft have, you aren't getting much feedback in the roll axis through the yoke. You would certainly be applying some force in the pitch are yaw axis. The ailerons generally don't feel much heavier as you input more roll on the yoke or stick. They will feel heavier as your airspeed increases and feel very light at low airspeeds. It isn't uncommon to find the yoke or stick commanding a very slight input to one side or the other. This could be a function of the slipstream, torque, fuel imbalance or even rigging of the aircraft.

Our joysticks are unfortunately unable to mimic this at all. You might need to hold the most gently pressure on the stick to counter this tendency, while in the real aircraft, the yoke or stick will generally remain wherever you command the ailerons to be. Keep in mind that this is true for all aircraft, but has been for the majority of the types I have flown. You wouldn't notice that you are holding ever so slight a roll input.

I would strongly recommend taking out all the dead/null zone on your controls if you have any as this will reduce the magnitude of the input you must make. It will more closely reflect the real behavior.

I raised autopilot as this is the only tool that will get you "true" hands off flight.

I've got a handle on the attitude/level flight and understand using trim to stay level. It's the roll that causing me trouble. I can see the instruments showing a roll beginning to start and can almost feel it as I know it's going to happen as soon as I let up pressure on the stick and or rudder. Some aircraft more so than others want to roll left but they all want to roll left to some degree. So your aircraft don't roll if you take your hand off the stick? I checked the fuel weight and it's balanced so something seems off...maybe it's me. I was used to flying in a rudder/aileron coordinated mode in FSX but am now using X Plane. In FSX I remember having this problem but added a passenger to balance the weight and it fixed it. Can't do that in X Plane 10 and not even sure that's the problem. Could be that's how aircraft are and I'm just not used to it but I don't know. The Baron 58 rolls to the right I think...King Air to the left, Piper Malibu Mirage to the left and the Diamond DA40 rolls to the left. I really want to get this thing figured out. Oh...not using any null zone either... Thanks.

Edited August 20, 2018 by Will273

[Will273 23]

By the way... I have a Logitech 3D Extreme with a twist handle for rudder. Bought a new one as they didn't have any other types of sticks...thinking my other one was bad but no....same thing. Took it back and ordered a CH Products Yoke...no rudder peddles...just the yoke. Well it helped a good bit...still rolls a little but not as bad and think since there's no rudder then X Plane coordinates it automatically and put rudder in. I hooked the Logitech back up thinking something's not setup right with it which is where I am now.

[Oracle427 45]

Yes, they usually will begin to roll if I take my hands off the controls, yes both in IRL and in the sim. The behaviors in the sim will depend on quality of the simulated model, so that does introduce variability that is hard to predict without knowing which products. I don't have many add-ons, so i will not be able to comment on most. I also can't speak for X-Plane behavior as it's been many years since I last used it. X-Plane could be a little squirrelly at times, but that is how flight can be when the air isn't smooth, as it rarely is.

I was just flying RW in a 172 in the evening in very calm air. I tried taking my hands off the yoke for a little while. I'd say in about 10 seconds I had rolled somewhere up to 5 degrees to the left. That's just the way it is and I did have a right seat passenger and about 17 gals of fuel per side at that moment.

I wouldn't use rudder to correct a yaw until the ball is not centered. The rudder is to keep the aircraft coordinated. If you use the rudder to correct roll, you will cause the aircraft to become uncoordinated. It will eventually roll in the direction of the yaw, but this isn't good technique, so use the aileron and the rudder together as required to maintain coordination. Too much rudder into a turn will cause the airplane to skid and can lead to an accelerated stall. Generally when at cruise speeds and power settings you aren't using the rudder very much. When you roll into and out of a turn at those speeds and power settings you may need rudder if you roll aggressively.

Exception to the above about not using rudder to stop roll is when stalling. Ailerons are not effective in a stall and may aggravate the stall and induce a spin, but that isn't what we are talking about here.

I would not hold rudder in cruise at all unless the aircraft was uncoordinated. If it is uncoordinated in level cruise, you might be out of trim, or flying with too much power if the ball is off to the right.

Like I said earlier, get rid of all null zones if you have any. Zero them out and you will need much less input to correct the tendencies. The lightest touch will solve the problem. The difference again is that ailerons don't self center in these aircraft. They aren't rigged to do so and aerodynamic forces don't take care of it either. You need to just keep a hand on it to keep it where the plane wants to fly straight. I have a Sidewinder 3d Precision Pro and with no null zone, just resting my hand on it gently is more than enough pressure.

Edited August 20, 2018 by Oracle427

[Will273 23]

I don't have many add-ons either...just Carenado Piper Malibu Mirage PA46/ Carenado/Alabeo Diamond DA40 and the Cruz Piper-sport Cruiser...all have good reviews. Nice to hear yours turned also and in the real world...that's good to hear...maybe it's all natural and the way they're supposed to fly. No one mentions having to keep pressure on the stick and rudder very often so I wasn't sure but then I think most people trim the aircraft out so they wouldn't say to much about it. I'm aware some aircraft don't have aileron or rudder trim so not sure how they deal with things like this. Thanks for telling me about your experience! Oh I also have a couple freeware jets...Gulfstream and Falcon 7. The Gulfstream IV turns to the left also for whatever that's worth...not sure if there's a connection there or not.

Edited August 20, 2018 by Will273

[Oracle427 45]

I wouldn't expect a jet to have any significant turning tendency, but I have exactly zero hours of experience in them. 🙂

I did have the opportunity to fly multiple times right seat in a Citation Bravo, but was just for fun and couldn't log the time. During one flight while in cruise I asked the pilot about what would happen if an engine failed. He proceeded to pull back the throttle on the left engine to idle and increased the throttle on the right engine, then turned to me said, "There you go."

I don't recall him adding any aileron or rudder input.

On a 182, if you don't apply rudder on the takeoff, you'll be turned 45 degrees to the left before you even go forward 100 feet. Prop aircraft are a completely different beast!