Step on the ball (coordinated flight)

In most types I fly, I would expect of myself that I would have the ball withing a half a ball diameter all the time, and only the occasional excursion one ball out while I was being sloppy. If I'm new to a type, and maneuvering, I would allow myself the whole ball out, while I got used to the plane. While test flying a recently rebuilt Cessna 206 the other day, I was rolling from 60 degrees one direction to 60 degrees the other, with no stop in the middle. I watched the ball (as I was assessing the rigging of the plane) and it was never more than half a ball out.

Happily, you can generally set your own standards with the ball - when you're flying alone. Aside from an approach to the stall, a ball out is not going to endanger your flight. If you are within a half a ball most of the time maneuvering a type you're familiar with, I'd say you can be proud of that... If you're doing stalls, or flying twins around on one engine, I'd aim for better than half a ball....

Pretty much what DAR said. Crosswind won't affect the ball at all of course, but use of rudder or power or elevator (airspeed variations) will.

I can pretty much fly the Chipmunk in balance without looking at the ball because I've a great deal of Chippy time. The same is not true for types where I have less experience.

I do remember checking out on the Chippy back in 1979 and doing power-off approaches. The instructor in the back said nothing... he just kicked the right rudder pedal about twice a second until I got the message that with power off the ball was out to the right and needed right rudder! These days, my feet do it without me having to think about it!

Vince/Pilot DAR - how much of your accuracy in balance, on a known type, is that you are anticipating a rudder requirement because of a configuration change or turn, and how much is it down to feeling you are out of balance and correcting automatically (i.e. reacting not anticipating)?

Ok. would it be fair to say that except from an intentional slip, there is never a situation where having the ball out of center helps or is desired while flying a single?

Yes. Apart from the very last bits of a crosswind landing (and the very first bits of a crosswind take-off for that matter), there is generally no benefit to not flying in balance.

There are some corner cases, obviously. C172 pilots sometimes fly one wing slightly high to restore fuel balance, you might do intentional slipping to lose a lot of height, and a few months ago I was flying in an R2160 when the locking mechanism on the oil dipstick access hatch failed and the hatch started flapping about. By getting the aircraft in a very slight sideslip I could subtly alter the airflow over the cowling, ensuring that the hatch stayed shut.

Oh, and aerobatics is of course one other huge corner case. Just as an example, when I perform a full aileron roll (360 degrees), I don't use any rudder at all for the first 180 degrees, since the adverse yaw keeps the nose up already. But the last 180 degrees need quite a lot of rudder to prevent the nose from dropping due to adverse yaw. Stall turns, hesitation rolls, spins and such obviously require a lot of rudder since you are deliberately yawing the aircraft, and even a simple loop requires careful rudder application to make it come out right.

Vince/Pilot DAR - how much of your accuracy in balance, on a known type, is that you are anticipating a rudder requirement because of a configuration change or turn, and how much is it down to feeling you are out of balance and correcting automatically (i.e. reacting not anticipating)?

It's all about anticipation, and then verifying you got it right. When you do a glider pilots license exam, one of the requirements is to make a series of S-turns with the slip indicator (really just a string of wool on the canopy) in the middle. With the long slender wings of a glider there is significant adverse yaw to overcome, and if you don't anticipate this but only react to it, the nose will be all over the place. And you will fail the exam. In fact, the adverse yaw in a glider is such that the amount of rudder you can put in becomes the limiting factor on how fast you can roll while staying in balance. Not the amount of aileron. (You can roll faster by putting in full aileron, but you won't have enough rudder authority to stay in balance then.)

I was taught to look at it the other way round: if the ball is NOT centered, nothing is really amiss; but you will be making yourself uncomfortable (one of my instructors used to complain about his delicate spine, in my earliest flights) and the plane will likely be behaving less than perfectly in aerodynamics and thus in fuel economy.

With a total of some 135 hours, and flying a VERY benign plane, I am only rarely finding the ball uncentered at the occasional check. It does come by nature, with time - or my plane should be even more benign than I thought.

Whats wrong with keeping "Straight" with rudder i.e. look out of the window. If the aircraft is flying straight, the ball will be in the middle

A quick look at the turn coordinator showed the ball all the way over to the left, and I thought how the foxtrot does that happen?

Excessive right rudder, or you've taken the power off in the descent and failed to compensate for the lack of slipstream.

The best way that I know to train your feet is 'rolling around a point'. Fly the aeroplane straight and level and pick a landmark on the horizon. Put your feet on the floor, and try to roll the aeroplane rapidly left / right / left etc about 45 deagrees bank each way. The point on the horizon will swing left and right opposite to your rolling (roll left, it swings right, and vice versa).

Now do the same but co-ordinate your aileron inputs with rudder. When the point on the horizon does not move relative to the windscreen as you roll around it, your feet are trained. For that aeroplane. And only in roll co-ordination.

But with experience will come fully automatic co-ordination of the rudder for all aspects of flight (or nearly - perfection is a long goal!).

Vince/Pilot DAR - how much of your accuracy in balance, on a known type, is that you are anticipating a rudder requirement because of a configuration change or turn, and how much is it down to feeling you are out of balance and correcting automatically (i.e. reacting not anticipating)?

The first time you fly a new plane, you have some latitude to "learn" the coordination. In my opinion, if you have free use of the plane for half an hour, to practice maneuvering, you should have the rudder coordination figured out by then. Really, a few steep turn entries and recoveries should be all that's needed.

Generally I anticipate rudder input, and lead with rudder in turns - it's how much to lead with, you have to figure out. Though there are planes which will drag themselves around with reasonable coordination with no application of rudder, you should not expect that. Even the much maligned C 150, which really does not require much rudder input during turns, when modified with the installation of a STOL kit then needs rudder.

On the other extreme, my Teal amphibian demands the proper use of rudder at all times. Even straight and level is going to require rudder from time to time just to keep straight. I once test flew a Cessna 185 floatplane with a tail boom, which I had just flown as a wheelplane two weeks previous. It flew fine as a wheelplane, so I was not expecting a plane which tried to fly sideways once on floats. Once off the water, I realized that to point it straight, careful application of rudder would be required at all times - but why? If I took my feet off the pedals, the ball would slowly hardover to one side or the other. I flew it around for a few minutes just to understand it, then carefully landed it back into the floatplane base, and declared it unairworthy. Obviously the installation of the floats was associated with this defect, so what had changed? I asked for the float installation drawings. Perhaps a ventral fin was required. These are common on Cessna floatplanes, and this plane did not have one. Nope, the drawing did not require one. It did, however, specify a Cessna spring kit, which connected to, and applied a force to the rudder cables. I looked down the tailboom, and sure enough - no spring kit. I told the owner that I would not test fly the aircraft until the kit was installed. He believed me, as he knew that I was required to spin the plane during the testing. Three days later, the kit was installed, and I took the plane up. It flew in excellent coordination, and my testing went fine.

I was once testing a Piper Navajo, with a 900 hour CPL as my observer right seat. I let him fly a bit, he'd never flown a twin. As required during the testing, and as I had briefed, I said to him "I'm just going to do this" as I slowly pulled back the left throttle to idle. From the right seat, I got a "what's happening!?!" as the plane obviously yawed. "Put some pedal into it" I instructed (surprised I had to). It seems the planes this CPL flew in his past did not demand rudder application.

I reluctantly agree with another poster, that often perfect rudder coordination is not required for an adequately safe flight. But when something out of the ordinary happens, or you want to be sure to be coordinated, instinctive use of the rudder is a good thing. If nothing else, rudder coordination is just good airmanship, and is an indication of meeting our own high standards - right?