rudders

Hello, I've had rudders for a very long time and am absolutely clueless on how to use them besides on the ground. Could someone please inform me of what they are used for in the air and how to use them? Thank you.

Hello, I've had rudders for a very long time and am absolutely clueless on how to use them besides on the ground. Could someone please inform me of what they are used for in the air and how to use them? Thank you.

Its just another flight surface like your ailerons and elevators. For the air you can use them to aim when doing gun runs, or even use them to burn off speed if your brakes aren't working fast enough. I only use them to burn speed of when I am coming in stupidly fast for formation, so if you are joining up like you are supposed to you shouldn't have to use rudder.

Under your attitude indicator is something that looks like a bubble level. I don't really know the technical terms and all that, but it basically shows your slip when you are in a turn. If you are turning, you want to use the rudder to keep that bubble in the center. Its not something you have to do, but it can help your turns a little.

Of course if you were to lose an engine, you would need to use the rudder to counter the thrust pushing you to one side. There are various other flight maneuvers you can use them for as well.

There are a variety of different uses for the rudders. What I use them for is what I said above, but people with more flight knowledge than myself can probably correct me and add a few things.

1) To help make coordinated turns; i.e.; changing direction without losing altitude.

2) To compensate for wind.

See this nice article on the source for all (useless) things:

http://http://en.wikipedia.org/wiki/Coordinated_flight

For the air you can use them to aim when doing gun runs

Although the rest is essentially correct, this is IMHO bad advice. The SAS is there for a reason. Do not try to throw it off it's game. Using the rudder with PAC is counterproductive.

Back OT, the A-10 has a stability system that will, inside it's authority, try to hold the ball centered, or in other words, maintain coordinated flight. The only time where you will need to interfere with this is in situations were excessive amounts of rudder need to be commanded, e.g. in high bank turns or in crosswind landings.

Although the rest is essentially correct, this is IMHO bad advice. The SAS is there for a reason. Do not try to throw it off it's game. Using the rudder with PAC is counterproductive.

That needs emphasis, so: what sobek said.

Using rudders to aim for guns is also counter-productive for more reasons than it fighting SAS/PAC. It also introduces a great element of instability to the flight - rudder input will cause one half of the plane to move faster than the other half, which on a straight-wing like this will very quickly lead to assymetric lift. (Incidentally, this is precicely what you do in a turn - in a left turn the right half of the plane needs to go faster than the left half.) So your initial attempt to correct your aim with yaw causes you to now have to correct for an inadvertently introduced roll moment. You then have to give stick to counter the roll, which introduces aileron break. Suddenly you've found yourself snapping too far in the other direction, and this will end in one of a few ways:

1 - a very bad gun run.

2 - PIO (pilot indusced oscillation). Your gun run will be ineffective and you will gradually lose control of the plane unless you "let go" and let it get stable. However, that's a bad idea if there's 15 .50 calibre machineguns trying to get a bead on you. ;)

3 - you allow the condition to escalate until you find yourself with crossed rudders, depart controlled flight into a spin, and since your altitude is low it ends with a crash.

Most of the time the consequences are limited to item #1, but #2 and #3 can very well result from that type of use if the pilot becomes target-fixated and does not notice what is about to happen.

Gun runs need to be set up carefully such that your aim corrections before engaging PAC-1 is extremely minimal. Basically you want to gently "fly" the CCIP onto the target and then engage your PAC-1, at which point the plane will fly itself (assuming you were in a stable attitude) onto until you get in range and let loose.

(Incidentally, the whole thing with "letting go" to regain stability is one of the weirdest moments in flight school. After entering a PIO, especially one where you end up with both yaw and roll moments osscillating as you fight with it, it feels very VERY counterintuitive to just let go. But assuming that the aircraft is a relatively stable one, and that you aren't about to fly into a building, it is often the best way to regain stability. If you have the luxury, don't try to "fix" things on the go whether it be a gun run or a turn on final. Start over and do it right instead. :) )

And of course ;)

http://www.faa.gov/library/manuals/aviation/pilot_handbook/

And of course ;)

http://www.faa.gov/library/manuals/aviation/pilot_handbook/

THANK YOU Bucic!!!

Long answer:

The Pilot's Handbook of Aeronautical Knowledge is good for the mechanics, but the Airplane Flying Handbook is a good reference on How To from a flying standpoint:

http://www.faa.gov/library/manuals/aircraft/airplane_handbook/

I recommend you look at Ch.3, page 3-7 (28 of 40), "Level Turns".

Keep in mind a single-engine prop plane, which they use for the examples has what are called "left-turning tendencies" that result from having a single spinning propeller (which has mass and causes all sorts of issues at low speed and high prop RPM).

You will not have to counter the left-turning tendencies in an A-10 like you do in a single-engine prop plane, so in general rudder is used to a lesser extent in the air (take that with a big grain of sand because it's a vast generalization).

While nosewheel steering is engaged, the rudder pedals move the nosewheel left / right AND the rudders (vertically mounted flight controls on the "H" tail).

At speed and in the air the rudders deflect just like the other flight controls (elevator and ailerons to name a couple major ones), causing the plane to yaw left / right. Ailerons result in roll, elevators control pitch. Rudders really aren't much different from an aerodynamic standpoint. When you pitch the plane up / down using the elevators the plane has less tendency to return to its starting point. When you deflect rudders and then release pressure, you'll notice the plane quickly tries to streamline back to the direction it was going before.

Short answer:

Now, to answer your question. The rudders are used primarily to coordinate turns (read the part in the Airplane Flying Handbook I linked above), to help in crosswind landings / takeoffs and to compensate for yaw if you lose an engine or have a partial power loss in one engine.

There is much more to it than that of course, but you have to start somewhere.

When I fly the sim, not having rudder pedals, I pretty much ignore rudder input in the air, which in the SIM you can get away with as long as both engines are operating and are at close to the same thrust output. On the ground and during takeoff / landing I use the keyboard shortcuts "z" and "x".

A more interesting question becomes, how do you use rudders differently in aerobatic flight vs. regular flight? For example, if I'm going to do a 90 degree high-speed aileron roll followed by high-g turn, do I even need to use rudder at all? Do I use it to counteract adverse yaw during the aileron bank or is it even worth it? In a high-g turn, there is very little slip (if any), so do I need it there?

I've been playing around with how/when to use rudders in various aerobatic scenarios, and I'm about as confused as when I started.

Wow, I didn't know that my simple question would spark so so many responses, but thanks!

A more interesting question becomes, how do you use rudders differently in aerobatic flight vs. regular flight? For example, if I'm going to do a 90 degree high-speed aileron roll followed by high-g turn, do I even need to use rudder at all? Do I use it to counteract adverse yaw during the aileron bank or is it even worth it? In a high-g turn, there is very little slip (if any), so do I need it there?

 

I've been playing around with how/when to use rudders in various aerobatic scenarios, and I'm about as confused as when I started.

IMO you should stop thinking "do I use rudders now?". Learn how rudders control yaw and what are the cross-couplings between yaw->roll and roll->yaw. Learn it and forget about "do I use rudders now?" the same way you don't think "do I use ailerons now?". Once you set yourself free of that invalid thinking you will be able to start thinking attitude. "What attitude (change) do I need and how it will change in a moment?".

Airplane Flying Handbook (thanks arteedecco) does not bite! Pilot's Handbook of Aeronautical Knowledge neither. They are simply written and written by professionals for general aviation student pilots i.e. not scientists. If you think you'll be better of it and just learn from the forums you're wrong. Use both but in most cases the forums will be the supplement and the AFH will be the core - not the opposite.

Yaw oscillations and pilot induced oscillations:

Aircraft yaw, unlike pitch and roll, is characterized by heavy oscillations. Once the A/c is thrown off neutrum by a rudder kick it will try to go back to the neutrum but will miss it on the first pass, much like a pendulum.

The key to understand the cause of pilot induced yaw oscillations (POI) is to understand the human body motor control (cerebellum part of the brain). A quick example. If you use a computer mouse for the first time in your life and the goal is to hover the pointer over an icon you move the mouse and the pointer, get a visual feedback on how it goes and continuously correct to aim at the icon, then finally stop. After a certain period of time of repeating that you will learn what physical movement correlate to exactly what distance of pointer movement. When this is established you will be able to aim at the icon with a single quick move of your hand. Same with the rudders. Until you develop that rudder movement->yaw response correlation you will not be able to control yaw properly and it will pose a risk of POI if you insist on fighting the oscillations.

One thing to note - it requires time! You can't rush it. I seriously doubt anyone in the world can develop such a control ability in less than 2 days, regardless of how many flight hours he did during those 2 days. So wait patiently until it starts to click. A good exercise is to sway the A/C by pushing left and right pedal repeatedly. Once in a few sways try to stop A/C from yawing AND oscillating, as much as it is possible, by applying a quick rudder input opposite to the direction of current yaw movement by pushing the rudders quickly back to neutrum at the right time.

P.S. By no means the Pilot's Handbook of Aeronautical Knowledge is "for the mechanics" or even "rather for the mechanics". I think they got the title spot on ;)

P.S. 2. IMO ED should start incorporating references to FAA handbooks more eagerly and tightly in the coming revisions of their manuals and training notes.

while we are on the topic of Rudders which set should i get ?

while we are on the topic of Rudders which set should i get ?

There are quite a few topics dedicated to the subject. Please use the forum search function.

P.S. By no means the Pilot's Handbook of Aeronautical Knowledge is "for the mechanics" or even "rather for the mechanics". I think they got the title spot on ;)

Hehe :), bad wording on my part.

I meant it is more about "nuts and bolts" (science) as in where are things located, how do they work, and the science of things, rather than as you mentioned with the AFH, simple pilot howto.

Cheers and thanks again Bucic!

A more interesting question becomes, how do you use rudders differently in aerobatic flight vs. regular flight? For example, if I'm going to do a 90 degree high-speed aileron roll followed by high-g turn, do I even need to use rudder at all? Do I use it to counteract adverse yaw during the aileron bank or is it even worth it? In a high-g turn, there is very little slip (if any), so do I need it there?

 

I've been playing around with how/when to use rudders in various aerobatic scenarios, and I'm about as confused as when I started.

I think to Bucic's point, don't think of using rudders differently in acro. versus regular. It's all the same (or maybe I'm misunderstanding your question :)). As he said you're not using ailerons and elevators differently, the principles upon which they work and how you use them remain the same while flying, regardless of acro / normal flight conditions. After all acro IS flight. You simply use rudders to keep the plane streamlined and coordinated... that is, unless your goal is to do uncoordinated acro., but that's a different story.

Look at the Pilot's Handbook of Aeronautical Knowledge in the sections about Aerodynamics of Flight (Ch.4).

I hesitate to give sweeping general rules of thumb (especially since what I'm going to say emphasizes instrument reference over stick-and-rudder flying), but because we don't have a good medium for teaching basic flight fundamentals...... in normal flight conditions you use the rudders to keep the ball centered in the Turn and Slip Indicator. (reference the A-10C Warthog manual, approximate page 110, Figure 88. Attitude Director Indicator, item 4. Turn and Slip Indicator).

Hehe :), bad wording on my part.

 

I meant it is more about "nuts and bolts" (science) as in where are things located, how do they work, and the science of things, rather than as you mentioned with the AFH, simple pilot howto.

 

Cheers and thanks again Bucic!

I'll still protest though, even the new wording ;) The PHAK not only contains fundamentals (not some redundant reading for overzealous student pilots) for understanding many "strictly pilot things" like spin development, coordinated turns, flight controls operation and many others. So... I propose that we settle on "PHAK can be read later or 'As Required' but it's not redundant while AFH is a strictly flying guide" :)

I hesitate to give sweeping general rules of thumb

I think specific instructions on specific maneuvers execution is what he needs. I suggest someone (an A-10 piloting savvy) post a track with some funky maneuvers as a tough reference.