Keepin' the ball in the centre

[MacTuc]

Hi all,. .am after some advice from those more experienced than myself - how can an instructor pass on to the student an appreciation of balance and co-ordination ?

few things frustrate me more than the motionless feeling on the soles of my feet as a student rolls into a turn or moves the throttle.

i haven't much ab-initio instructional time, so i'd appreciate any suggestions of techniques to instill "ball" awareness. can the inner ear/seat of pants sense that we all use be taught to a student, or does one find that it only comes through experience (unfortunately, i fail to remember my own progression..)

any feedback will be gladly appreciated,

cheers,. .dave

[Tinstaafl]

I responded to <a href="http://www.pprune.org/cgibin/ultimatebb.cgi?ubb=get_topic&f=5&t=000509&p=" target="_blank">This Thread</a>, also about balanced flight. Mine, and other's responses have suggestions that should help you.

I would also add that getting your student to follow you through while you demonstrate a perfectly co-ordinated roll <img src="wink.gif" border="0"> :) is helpful to give them the 'feel' of how much input is appropriate.

[john_tullamarine]

.. perhaps the perceptual problem is one of degree and/or stimulation of the senses .. ie the student fails to realise that the turn is unbalanced. Perhaps you might try a series of exaggerated unbalanced turns to over emphasise what the problem is and how to correct it .. whether with top or bottom rudder as the case may be ?

[The Stooge]

Mac,. .It is something that you just have to keep chipping away at. At the end of the day all you can do is advise the student of what they are doing is not correct and let them realise in their own time. A good way to teach is to get the to slow every manouver down to a point where it is rediculus(?). Get them to say BANK then have a pause then BALANCE they do that and have a pause then get them to say ATTITUDE then hold it the whole way around. Whilst in the turn you have to get them to conciously be cheching the attitude and also the performance ie: AOB,ALT,ASI,Slip indicator. After all power+attitude = performance and all the rudder does is increase the performence. If they want to fly out of ballance all day who cares.

[yxcapt]

I see a lot of the lazy feet sickness even in experiance pilots. What I have found to help is the old yaw string. I find it keeps the pilots eyes out side and not inside watching the T & B or turn coordinator. They instantly see the quality of their turn.

I teach in Citabrias and gliders which require the use of rudder. If a pilot has trouble with cooridantion we try several roll in to and out of 45 degree bank turns. I have them switch direction after about 30 degrees of heading change. Have them start out slowly and gradualy increase the roll rate. People will get so engrossed with the turns that they let the altitude go. So you will have to remind them about pitch control.

[MacTuc]

People, thanks for the replies

I'll be sure to try the exercises suggested, tho' i'm likely to embarrass myself a little having the student watch the ball while i demonstrate a perfectly co-ordinated turn entry/exit <img src="smile.gif" border="0">

I suspect that such sequences will serve to demonstrate that one's feet arent just there for taxiing, but the 'feel' will only come with time.

thanks again,. .dave

[Checkboard]

There is another exercise I used to use in the intial stages of aero instruction that you might like to try.

If you set up a wing rock of around 30° left and right, while flying straight and level, and with your feet off the rudder pedals, you can show how the nose of the aircraft wags back and forth in a "U" shape, due to the adverse yaw.

Now do the same wing rock, but with rudder input, and you should be able to nail the nose in the one place, with practice. It is initially like trying to pat your head and rub your stomach at the same time.

It amazes students how much firm rudder is actually required, like around ¾ travel.

[Tinstaafl]

That's the 'roll around a point' that I was so in-elegently trying to explain in the thread I mentioned. <img src="smile.gif" border="0">

[MacTuc]

CB

sounds like another good idea, will be sure to give it a shot.

cheers for the suggestion

dave

[RVR800]

I dont think I ever really got the hang of it until I went asymmetric in a twin!

You sure need to be aware of it then...

[Checkboard]

MacTuc, the hard bit is when you do the same exercise inverted! (Being inverted requires opposite rudder.)

The exercise is a good way to back up the theory on adverse yaw, as anytime the ailerons are deflected, you need rudder to balance the aircraft - even with assymetric or frise ailerons (i.e. on Piper or Cessna light singles.)

Along with explaining adverse yaw, I would describe the balanced turn thus:

[quote]If we performed a turn at 0° angle of bank (holding up model aircraft in a flat turn), then you can see that all of the control input would be from the rudder (wiggle rudder on model, and ignore secondary effects.) OK?

If we performed a turn at 90° angle of bank (AoB), (holding model), then you can see that all of the required control input would be from the elevator (wiggle elevator on model, and ignore the fact that, as there is no lift, a level balanced 90° AoB turn is impossible) OK?

So ... when we turn at an AoB somewhere between 0° and 90° (usually 30°), then while established in the turn, we need some elevator (backstick) and some rudder (with the turn) in order for the aircraft to remain balanced.

Now to introduce the entry - when rolling into the turn, deflected aileron needs coordinated rudder and we are starting to turn, which needs rudder as well.

In the turn we need rudder as explained above.

Rolling out of the turn we can relax the rudder, as the opposite aileron requires opposite rudder to balance, canceling out the rudder still required for the turn.

.. so in a standard turn, the rudder requirement is: Lots of rudder to roll in, a little rudder during the turn, relax the rudder rolling out.<hr></blockquote>

Hope that helps, and isn't telling anyone stuff that is too obvious. <img src="smile.gif" border="0">

[Checkboard]

Actually, while I am on the subject ... <img src="smile.gif" border="0">

Another time when I see the rudder mishandled in light tricycle singles, is during the take-off.

Most students are aware of the left rudder (in yankee engined aircraft) requirement during high power operations, like climbing, but don't really consider what happens during the take-off.

As you accelerate down the runway, the nosewheel steering is providing most of your directional control, keeping you on the centre-line. When the aircraft rotates, you lose that directional control, so you have to increase the left rudder pressure on rotation in order to stop yawing.

Wander down the end of the runway, and watch a few take-offs one day. Almost invariably you can see the aircraft rotate, yaw to the right, then the pilot will dip the left wing in order to straighten up.

That wing dip is a sure sign that they have failed to increase their rudder pressure on rotation in anticipation of the requirement for the high power. It's a minor thing, but just shows a lack of "polish"!

OK, OK call me pedantic.

[yxcapt]

Checkboard-

"Yankee Engines"? Do you mean the US built Lycoming or Continatal? This means right rudder not left.

And a question about your inverted turns. To make a turn to the left inverted, you use right stick and right rudder - correct? I don't think your post made it clear.

[yxcapt]

You also mention a little rudder during a turn. In a normal turn (in smooth air) both ailiron and rudder are nutrial unless you have a real long wing and/or steep bank. In that case over banking tendance would be present and thus call for crossed controlls to make a co-ordinated turn.

[MacTuc]

CB

thanks again for your continued responses - the model description of one extreme (zero bank) to the other (knife-edge) seems to be be an effective teaching method.

agree also with the takeoff/high power scenario, though, like yxcapt, i think our respective props are turning in opposite directions <img src="smile.gif" border="0">

again, i appreciate all the good suggestions on this important topic

dave

[Checkboard]

haha - shows how long it's been since I flew a piston single! I was actually thinking about it before I wrote it, and thought that it should have been the right rudder, however I seemed to remember my left foot doing most of the work, so I went with my heart, not my head.

yxcapt, for a balanced, level left turn while inverted (that is left as the pilot sees it, not a following upright aircraft) you use right stick, forward pressure and left rudder to co-ordinate.

[B2N2]

I usually start in the first lesson by demonstrating a turn without rudder and a turn without ailerons.The student will notice it "feels funny" and looks odd.. .I then do it again but have them look at the ball and the nose of the aircraft.. .Then demonstate a couple of coordinated turns to show the difference.I let them fly for about 30min using only the rudder..... .Shows how to use your feet and trim correctly.. .I then say "right rudder" about a 1000times till they get their PPL.Some get it quicker than others.