I have a recurring problem that finally got an explanation on the other day. I want to hear what you guys have to say about this.

I have noticed now and then that during turns, I tend to cross control when it's not needed. In what I intend to be a coordinated turn, I sometimes realize that I am holding in some opposite aileron.

During my BFR the other day(in a Bellanca Decathlon) I noticed I was doing it again and the instructor called me out on it too. He told me I was holding the inside wing up with opposite aileron because I was too heavy on the inside rudder input. I replied that I was trying to coordinate the turn (the ball WAS centered.) He said that the rudder input was only needed when initiating the turn, simultaneous with the aileron input. As soon as the bank was established I could relax(center) both rudder and aileron and just pull through with elevator until rollout. All of a sudden this seemed so obvious.

It worked beautifully in the Decathlon, but is this only because the Decathlon has no dihedral? How is this different in the Cessna? Is it a question of static stability designed into the aircraft?

Ok, now the secret's out-- I'm still a noob.

Z

I figure I'm doing well if I can keep the turn coordinator ball inside the cabin, let alone in the center! A couple times, I've been startled during a turn in turbulent air by a tapping on the plexiglas next to my ear- it was the turn ball wanting to come back inside!
Tailwheel airplanes need more attention paid to the rudder during flight too, not just during TO & landing. That's been my experience with the 170 & a Pacer anyway.

Eric

I've been thinking about this some more:

In a turn, say 30 degrees of bank, the high(outside) wing has a higher airspeed than the low wing, simply because it is turning around a longer radius, and has a higher angular velocity. This means the high wing is producing more lift, and therefore more induced drag, so you HAVE to keep a little inside rudder input or you'll SLIP out of coordination.

Too much rudder and the aircraft will want to bank more, hence the reason I was subconsciously holding in some opposite aileron to pick that wing up. Coordinated turns are something that have never come naturally to me, I have to practice a lot.

Still wondering about the effect of dihedral in this situation.

Good article by Machado in AOPA Pilot this month about similar issues.

There is a way to diagnose the quality of turn without having to look down at the ball indicator. Disturbed relative wind noise will tell us something is wrong. We can compare the speed the nose is moving horizontally with the angle of bank. More bank requires a faster nose movement which requires more rudder in the direction of the turn. When we don't use enough rudder, a common slip, the nose seems to hang up and not want to move around toward the target. Relative wind noise, perhaps rattle, butt cheek pressure in the direction of the turn. When we stomp the rudder too much, an uncommon skid, we also get the disturbed relative wind noise. The noise jumps around too fast for the angle of bank. Relative butt cheek pressure is away from the direction of turn. Perhaps we bang our heads against the side window.

It is the wing engineering, not the nose gear, that causes modern airplanes to make acceptable but sloppy aileron only slightly slipping turns. Piper uses bungees between the rudder and aileron. Cessna warps the portion of the wing where the aileron is hung. It is washed in so it is flying at less angle of attack. Frise ailerons on all modern airplanes cause the up aileron to have some drag by hinging so the leading edge sticks out below the bottom of the wing (dirties up the wing producing less lift.) All of these things mitigate but do not eliminate adverse yaw. Thus, modern wings false teach that no rudder is needed in a turn.

In really old airplanes like the Stearman, even with a 90 degree bank, there is no turn until rudder is applied. Dutch Rolls were effective at any angle of bank to teach coordination of rudder and aileron in a turn. In modern airplanes I require 45 degree banks when teaching coordination. This is enough bank angle to do away with the aileron only turn possibility. The modern airplane can no longer false teach here.

In steep energy management turns, rudder throughout the turn is necessary. The bank is continuously increased throughout the turn and upon nearing ninety degrees of bank (it doesn't have to be that steep but makes a better illustration,) the rudder is actually helping push the nose down. When low in a steep turn, we need to push the nose on around so that we can level the wing before encountering terrain and obstacles. We don't want to put a down wing into something. Also, when maneuvering near the ground, we can't safely be looking at the ball or anything else on the dash.

hotrod150 wrote:I figure I'm doing well if I can keep the turn coordinator ball inside the cabin, let alone in the center! A couple times, I've been startled during a turn in turbulent air by a tapping on the plexiglas next to my ear- it was the turn ball wanting to come back inside!
Tailwheel airplanes need more attention paid to the rudder during flight too, not just during TO & landing. That's been my experience with the 170 & a Pacer anyway.

Eric

That's funny right there............. I don't care who you are...

Not so sure I'd lose much sleep over it, as long as you're reasonably coordinated during the turn. Try relaxing the rudder more while in the turn, and you won't have any need for opposite aileron. You're skidding the turn a little, if you're holding more rudder into the turn than necessary and compensating for that by opposite aileron. The important thing is not to skid your turns too much at low airspeed and close to the ground, lest the ground reach up and smite thee.

Cary

After recently watching the video in this thread,

viewtopic.php?f=15&t=12320

I Found the ball knocking on the window asking to be let back in. LOL. I was on a right down wind to RW21. Winds were 320@17G28. I learned a good lesson that a strong wind can fool your seat of the pants coordinated turn.

Wow, contactflying is really dredging the depths of T/P/P. Look at the date of the original post.

Reminds me of a similar conversation on my last FR. Takeaway was that cross-controlled and uncoordinated are two entirely different things. I think I have a better written description someplace I'll try to find and post.

He's looking for that post that Orville & Wilbur made back in the early days of BCP.org.

Didn't notice the original post date. Can we assume that you've learned how to turn, since then?

Cary

Cary wrote:Didn't notice the original post date. Can we assume that you've learned how to turn, since then?

Cary

Nah, still have no idea what I'm doing.

Cary brings up a problem faced by those of us who teach maneuvering flight like crop dusting and pipeline patrol: pilots perceive that it is dangerous to bank near terrain and obstructions and that using the rudder in a steep bank will cause skidding. Dangerously, just the opposite is true. We need to know wind direction to manage our ground speed in the turn. We need to turn aggressively to miss obstacles and terrain. Going over is usually more dangerous than going around. Finally we must push the nose around in a steep turn near the ground. Steep turns, at slow airspeed and ground speed after pitching up to reduce speed (the slower we go the faster we turn), happen quickly. This quickness is necessary to get the nose onto target prior to hitting things or putting the low wing into something. When the nose is moving rapidly toward the target, much rudder is necessary. We reverse direction and go back to 3' AGL in around sixteen seconds empty and 30 seconds at max gross.

Cary is correct about coordination being overrated. That is if we are always high and if we never bank very steeply. Wing efficiency is very important when maneuvering aggressively to miss things.

contactflying wrote: In really old airplanes like the Stearman, even with a 90 degree bank, there is no turn until rudder is applied. Dutch Rolls were effective at any angle of bank to teach coordination of rudder and aileron in a turn.

Actually, a Stearman will turn without rudder, but it feels like you are holding a sheet of plywood out the window of your car at 90 mph. I just got done putting a student through a full stall, spin syllabus in the Stearman to include falling leafs. When practicing steep turns, the cross control issue usually take place when a pilot initially sets the angle of bank (at least 45 degrees), without adding the appropriate amount of rudder. When he looks inside momentarily and adds inside rudder to get the ball in the center, the bank increases several degrees, nose drops, and airspeed increases, which subconsciously we don't like, so the outside rudder "fixes" the problem. I usually teach leading with a half second of rudder before rolling to the desired angle of bank so you the ball never gets safely tucked away in the corner.

That said, I always let my students mess around with the corners of uncoordinated flight, and slow flight, but not at the same time. Unless they're just not getting it, then I take em' up to about 5,000' and say "now go through your stall sequence again, and see watch happens if you don't keep the ball entered.."

The key lesson is that you need 2 things to spin; exceed the critical AOA (stall), and be out of coordinated flight (slip/skid). Otherwise, they can fly sideways all day long, or gently mush the stall till they smack the ground...right side up. I agree, a Cub or a Stearman gets the fundamentals through easier because there's no stall horn, and there is no aerodynamic counters designed in the aircraft. Just lots of induced drag, adverse yaw and wind noise. Too much information for a dead thread...second cup of coffee...

Mike-

I thought in any old aicraft (but especially Cessna) because they naturally want to roll further into the turn because the outside wing is going faster relative to the inside wing, you have to "hold off" with opposite aileron to maintain angle of bank. So you would always needs some rudder to keep the balance?

Battson- Maintaining an angle of bank is a level turn concept. Provided we have sufficient vertical space, we can allow the bank to steepen until the nose comes onto the target. We cannot keep the airplane from descending without lots of excess engine thrust. We have to allow the nose to fall through naturally (don't hold back.) When we decide to stop the increase in banking, we have to use lots of rudder against the turn as we stop banking or level the wing. When we are slow (turning without excess engine thrust to hold it level,) more aileron and much more rudder must be used against the turn than when entering. Adverse yaw is most pronounced at slow speed. Dutch Rolls take care of both entry and exit of turn coordination problems. We can't hold the distant point with the nose unless we try to push the nose right then left then right etc. when we bank. How do we hold the nose straight while trying to push it (with rudder) around the horizon as in a turn? Dynamic control movement; forget pressure. Control pressure is for IFR work so we don't upset the aircraft. Dynamic control movement is for contact work when we want to miss things by just a bit but also want to be assured that we don't hit them.

Geeze..after reading all of these posts I think I'm going to have to get some further training. The ball and my butt seem to have a connection and no matter what speed and angle I bank, I seem to react to it automatically. Of course I've had this aquired over some time..AND all planes don't react the same. I have to remember a Cub, a Citabria, and a Cessna all react differently in a tight turn or stall. If I get into a new aircraft, I like to see how it slow flights, handles increasingly sharper turns, and how it stalls..both power on and power off. This proceedure gives me insight as to how the aircraft will handle..especially in slow flight on final.
Go figure.
HC

HC-All good information, but the comforting thing about a Cub, Citabria, or Cessna is that by design specification in Part 23, they must respond to controls almost identically. This is not true of newer, and more expensive light sport.

contactflying wrote:HC-All good information, but the comforting thing about a Cub, Citabria, or Cessna is that by design specification in Part 23, they must respond to controls almost identically. This is not true of newer, and more expensive light sport.

Um, the Cub and most Cessnas are NOT part 23 airplanes. The Citabria is a "quasi Part 23 airplane" since the 7AC type certificate it's based on was updated for Part 23 compliance....sorta.

MTV