Flyer Article on Rudders

[High Wing Drifter]

Just read a Flyer article on rudders. It seemed to give advice that contradicts that taught in my PPL and ATPL along with confusing terminology. Amongst that lot was:

* Sideslips became Forward Slips.

* Crabs became Sideslips.

* You should correct a win drop with aileron and never rudder: I was taught never to pick a wing up with aileron as you will probably stall the tip and increase the drop, hence the need to correct the drop with rudder and that you should never use the aileron in a stalled condition. That makes logical sense to me so I was happy with it.

Is the article more correct than my tuition?

[Flap40]

Just to add to your final point. In a stall the rudder should only be used to stop the wing drop not to bring it back up again. This would be more likely to induce a spin in the opposite direction!
I know that it is what the books say, but you would be surprised just how many people get it wrong!

[Angel´s One Fife]

Flyer mostly right. You all wrong. 'nough said

[Genghis the Engineer]

All seems correct to me. My only issues with the article would be:-

(1) A sideslip is a sideslip, dressing it up in different terms because you are using it for different things in my opinion just causes confusion. (In other words, I just don't like the term "forward slip").

(2) Mr Heald has made no mention of the use of rudder as a reserve control in the event of an aileron failure - most aircraft are specifically designed to permit this, and I can think of at-least one case in a light aircraft, and another in an airliner, where the pilot did just that.

G

[Atlas Shrugged]

Genghis said:
Mr Heald has made no mention of the use of rudder as a reserve control in the event of an aileron failure - most aircraft are specifically designed to permit this, and I can think of at-least one case in a light aircraft, and another in an airliner, where the pilot did just that.In that situation the technique is to keep the yoke centred and use it only for elevator control and not turn it even slightly. The easiest way to do it is to hold onto the shaft then all you need do is use the secondary effect of rudder to control the roll (left rudder initially yaws to the right which causes a roll to the right.....). It's fairly easy to fly an aircraft using just rudder, although I did have a right rudder cable snap on me once and following a few minutes entertaining flying I figured out that I could still use the left rudder with almost full deflection. All I had to do was trim the rudder fully to the right and fly with left rudder pressure to correct it. Uncomfortable, but perfectly manageable.

I guess the same procedure may apply in the event of a broken elevator cable. If you lose up elevator, trim fully nose up then keep downward pressure on the yoke against the trim - I don't really want to test that one out though!

AS

[bookworm]

* You should correct a win drop with aileron and never rudder: I was taught never to pick a wing up with aileron as you will probably stall the tip and increase the drop, hence the need to correct the drop with rudder and that you should never use the aileron in a stalled condition. That makes logical sense to me so I was happy with it.

Most modern aeroplanes have enough washout that the ailerons remain effective when the mainplane is well into what we'd recognise as a stall.

The danger at stall is not really about position of controls but about roll. In the normal flight regime, roll is stable: if you initiate a roll and then centre the ailerons, the roll stops. But in a stalled regime, roll is unstable: if you start to roll, it wants to continue to roll. And it's that that can cause the autorotation (spin) to start. Anything else that can cause a difference in AOA of the wings is a Bad Thing.

So the most important thing at stall is to avoid roll. If the wing is dropped, leave it dropped until you're out of the stall regime.

[DubTrub]

Most modern aeroplanes

And how many are modern? Say those manufactured in the last 40 years?

[Genghis the Engineer]

Modern, in this context, is post the introduction of FAR-25, so designed after about 1950.

G

[BraceBrace]

Bookworm, you compare stalled and not stalled, but you have to consider what happens when moving into a stall. The rudder is to prevent making a not-stalled condition of a wing into a stalled condition (first thing they learn you when practicing stalls is to keep the stick/yoke centered at all times, isn't it?)

In a spin ie (both wings stalled), yes, the roll continues. Normal turn (both wings not stalled), the roll is stable.

However, when at high angle of attack, close to a stall, if you move the ailerons, both wings encounter a slightly changing AOA. For a turn to the right, the left wing (downgoing aileron) will get a slight increase in AOA. This can make the wing stall. So while you expect the left wing to go up, it goes into a stall. The right wing has a slightly lower AOA and will not stall.

That's how it was explained to me, I believe you can compare it with a snap roll? Never done one myself, but the demonstration of the snap roll on a A152 was one for the memories (the instructor caught me by surprise and it was almost :yuk:-time :D )

And forward vs sideslip. Always like they way they named it. With a forward slip the nose of the aircraft is pointed to a side, and with a sideslip it's pointed forward. Both are uncoordinated. A crab is coordinated and flight-technically nothing more than flying straight ahead (no turn). You almost always crab in cruise...

(ps was the article on jets or piston aircraft? it can make a difference)

[MayorQuimby]

Was taught that rudder should not be used for picking up a wing or preventing wing drop. Instead it should be used for preventing yaw.

[Algirdas]

The truth of all of this is that all controls have primary and secondary (and even tertiary) effects - and the balance of these is different for different a/c types. I get really nervous about any statement that says 'never' - there are circumstances when a free-ish thinking mind will save the day by doing the right thing rather than following the 'correct' dogma.
I have experienced a stalled wing in the cruise during turbulence - trying to bring it back up on ailerons made the drop even more severe (as would be expected) - a sharp nose down to gain speed effected an easy recovery. Had I had a passenger on board, this would probably have been quite frightening for him/her.
However, I have also experienced a very sharp wing drop in rotor effect near the ground, on final, and in this case took it out with rudder - I did not have sufficient height to drop the nose, and for the same reason would not risk using aileron - don't know if the wing was technically stalled in that case or not, but rudder did what I wanted. If I'd had a mindset that said I should use aileron not rudder in all cases, I believe I would have acquainted my face with the tarmac, shortly followed by my posterior.....

[Croqueteer]

There are other situations, which I have mentioned before, where the rudder can save your life. If a non IF pilot ends up in IMC, which of course he shouldn't, the safest way to climb from a trimmed S&L setting is to apply full power, fold your arms in front of you, and keep the a/c on a constant heading using the DG and rudder only. It also works by keeping the horizon level, or the T&S in the middle. The same works on a descent starting with a trimmed descent at about 1600 to 1800 rpm. Try it.