Interesting: No rudder needed at all???

[UnAnswerd]

So I went up for my second lesson, and was introduced to making turns. My instructor would position a movable marker on the heading indicator, and have me turn to the heading. We did so at a 30-degree bank. The airplane turned solely with the use of aileron deflection. No rudder was ever needed. I really didn't expect this. Is this typical???? You figure in a left turn the left aileron moves up, decreasing lift on that wing while simultaneously increasing lift on the right wing, resulting in a bank to the left. But you'd think the right wing would also be developing more drag, causing the plane to actually want to turn right. Nevertheless, no rudder was needed. Can somebody please help me understand this?

Any information would be greatly appreciated.

 

[banned username 2]

You turn most likely wasn't perfectly coordinated, but it turns none the less... An airplane turns due to the horizontal component of lift, not the rudder...

Check out this diagram...
http://www.gleim.com/images/aviation/ltf/howturn.gif
and
http://www.centennialofflight.gov/essay/Theories_of_Flight/Performance_Class2/TH25G5.jpghttps://ntc.cap.af.mil/ops/DOT/school/L23CockpitFam/images/turn.gif

 

[SiuDude]

Most trainers require little or no rudder during left turns and a little rudder during right turns at cruise power settings.

 

[Lead Sled]

To put it quite simply (perhaps too simply), rudder input is required to counteract adverse aileron yaw. Older aircraft designs (ie J-3s and 7AC Champs), frequently didn't employ yaw reducing techniques such as differential aileron throws and require much more rudder input as a result. More modern designs such as Piper's PA-28 series are so forgiving that some students never really learn "what their feet are for". Some aircraft, like the MU-2, use spoilers for roll control and consequently have minimal need for rudder input.

Lead Sled

 

[midlifeflyer]

As other pointed out, the rudders are for coordination- to overcome adverse aileron yaw. The airplane will turn with aileron only, but the turn will initially be uncoordinated.

We'll use a right turn as an example. If you look out the window at the nose carefully, you will see the nose drift slightly left as you begin the turn and then "catch up" with the rest of the airplane. It's that initial tendency to drift in the opposite direction that you are correcting with your feet

That "catching up" is part of the airplane's stability. It "wants" to fly coordinated. You can demonstrate the same phenomenon with rudder-only turns. From straight and level flight make a right turn using rudder only. The airplane will yaw to the right, but the airplane will eventually bank

 

[lawfly]

No Rudder

And when you get to ILS approaches, you'll make heading changes of, say, two degrees, with rudder only...

 

[flyer172r]

If you ever fly a glider you definitely will have to use the rudder to make a turn. If you forget to the glider will remind you pretty quickly. Most airplanes are designed to not need a lot of rudder.

 

[Singlecoil]

Or it could be that you have a lousy instructor and he is moving the rudder with his feet while you fly.

Horrible technique on his/her part. You might ask him if he is doing that.

 

[mmmdonut]

And when you get to ILS approaches, you'll make heading changes of, say, two degrees, with rudder only...

No you wont! This is the stupidest thing I have ever heard taught by an instructor. Try doing that in a 757-300 with the passengers in the back moving 30 feet laterally when you yaw the plane about that axis. You'd have puke everywhere.

If you are off the localizer, make a normal turn a few degrees until you are back on and then turn back, applying any correction.

Using the rudder for small localizer corrections is lazy and no one should be teaching that.

 

[Lead Sled]

And when you get to ILS approaches, you'll make heading changes of, say, two degrees, with rudder only...

Bad idea. It works OK with little airplanes, but as mmmdonut said, it's not a good idea once you get into larger aircraft.

Over the years, I've given many instrument competency checks and I've seen pilots try just about every imaginable way to track the localizer. (The wildest was a Cessna 310 jock who insisted on using differential power!) The secret is not to let the error get too big. Stop the error from getting worse, then correct back to where you want to be. With all respect to your instructor, I would have to question his technique for anything other than very minor corrections. Aircraft with flight directors and autopilots fly the localizer with the ailerons. All in all, it's probably the best way to accomplish the task.
Lead Sled

 

[midlifeflyer]

Bad idea. It works OK with little airplanes, but as mmmdonut said, it's not a good idea once you get into larger aircraft.

I know a very experienced DE who doesn't like it much in little airplanes either.

If we follow the common wisdom that the max angle of bank is the lesser of standard rate and the number of degrees to turn, those 2-3° turns aren't going to have much bank anyway. But, I was taught the rudder turn also, and my ability to hold the localizer with small corrections increased a lot when I started making even those small turns coordinated.

 

[philo beddoe]

Rudder only is very lazy and is a substitute for learning to use corect technique.

To the original poster:

Here's an experiment to try next time you fly:

Slow to stall + 20 or so knots.

Try making turns with very large aileron deflections with and without rudder.

You wll see the difference, I asssure you.


Now, as to why you 'didn't need' rudder in your instructor's demo:


Adverse yaw is directly proportional to the amount of aileron deflection.

The stabiliing effect of the vertical stabilizer is enough to overcome most of it in a typical Cessna or Warrior/Archer. Also the higher the airspeed, the better the stabilizing effect. Try the experiment I described, and you wlill definitely see the need for rudder.

Poor rudder use is a big reason that many IFR students fall apart on the last 200' of an ILS. The uncoordinated 'aileron only' technique works really well until near the end when more precision is required.

One of the reasons for the 'rudder only' technique is that it IS easy to make small accurate heading changes this way, But is is sloppy, lazy technique.

Miniscule, but correct use of rudder has worked well to 'fix' ILSs for the many dozens of IFR students I have worked with.

 

[UnAnswerd]

More modern designs such as Piper's PA-28 series are so forgiving that some students never really learn "what their feet are for".

Yep, that's what we were flying. My instructor did have me push rudder only. The plane yawed, but things were clearly uncoordinated by observing the inclometer.

 

[UnAnswerd]

Or it could be that you have a lousy instructor and he is moving the rudder with his feet while you fly.

Horrible technique on his/her part. You might ask him if he is doing that.

I did. He had me turn the yoke and we make a turn. Since I was under the impression that you always had to use the rudder, I was surprised, and proceeded to ask him if he was applying any rudder. He said "no rudder". I'm sure I'll learn more about the rudder as I progress further into my training.

 

[paulsalem]

The rudder is actually only there to made up for a flaw in the design of alerons. Pick up a copy of stick and rudder. Amazing book. It dispells many aerodynamic myths.

 

[Lead Sled]

The rudder is actually only there to made up for a flaw in the design of alerons.

It's not really that simple and there are other valid reasons for rudders than merely to compensate for adverse aileron yaw. Rudders come in pretty handy when you need to slip or when you're landing in x-winds.

Unanswerd...

I'm not about to second guess your instructor's method. Granted, it's not the way that I usually choose to teach turns, but he probably has his reasons. The last thing your CFI needs is to have a student that runs to a forum like this one every time he he tries to introduce a new concept. Relax, take a few deep breaths and get on with the program. I'm sure that he'll teach it properly. If he doesn't, this forum isn't the place to go to get things sorted out. If it ever comes to that, you'll simply need to find another instructor. Like I said, give it a bit of time.

Lead Sled

 

[lawfly]

Rudder

Rudder & The ILS

I didn't say I do it or teach it. I said "you'll be...with rudder only". I do know at least one guy, a DPE, who teaches it and the heading change at issue when I flew with him was literally 1 or 2 degrees, during an ILS. He demo'd his rudder-only technique to me not too long ago. Hey, it was his show at the time. He did comment about "people in the back" (we didn't have any at the time; it was an 8-10 seater).

I just teach "small corrections" on the ILS. And have shot many to mins in actual w/pax on board. No puke yet. (The DPE's demo came after my own aileron-guided bracketing. It's just his "thing", apparently.)

The intended implication of my earlier post was that given Unanswerd's present tendencies toward aileron-only turns during relatively large heading changes, he might have a tendency toward rudder-only during very small heading changes, on a localizer, and there is at least one DPE encouraging rudder-only in heading changes of one or two degrees, on a localizer. Unanswerd's original post reminded of the DPE's presentation.

 

[Singlecoil]

The rudder is actually only there to made up for a flaw in the design of alerons. Pick up a copy of stick and rudder. Amazing book. It dispells many aerodynamic myths.

That would be true if you only flew airplanes with counter-rotating props, or pure jets. Even Turbo-fans have left-turning tendencies due to the size of the fan. In a single engine airplane, or a twin that doesn't have counter-rotating props, your feet will (should) move everytime you move the throttle(s).

edit: I guess I left out gliders...

 

[Goose Egg]

My students sure don't seem to think that they need any rudder on the takeoff roll. I beg to differ with them.

-Goose

 

[lawfly]

Rudder During Climb

I've trimmed it in during climbs to altitude in a TBM-700. Small price to pay, though...It also comes in handy in multis when one stops turning.