Climbing Right Turns

Jaybird180

Jaybird180

Final Approach
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Jaybird180
Yesterday I decided to do some pattern work toward the close of the day. The plan was to do 10 with the goal to work out some better markers, trim and power settings, etc during the daytime, allow my eyes time to adjust to nighttime while I continued on through the night. Between the 1st takeoff and the last landing it was a total of 1hr 40 mins. I think I may have actually done 11 or 12 circuits (missed count?) but ah, well...

I was working on bettering my Vx climb outs during each circuit (there be monsters at the departure end) before I have to make a (10-20*) shallow right turn (~200agl) for power lines, then retracting the flaps. I now realize after referring back to the POH that 10* flap Vx is about 10KIAS slower than the speed I was using and I'll give that a try next time out.

I am getting much better with noticing the adverse yaw in the turns and don't need as much to look at the inclinometer during turns; I just take a glance at it now and then, make an input and note what I can do better.

There is a little peculiarity that I noticed on climb out and that is that my climbing right turns were not ball centered. About the best I got them was 1/2 ball deflection to the right - yet glued to that spot. I'm wondering if it's because of an uncoordinated climb out, shallow turn, configuration changes or what's producing it, but at the turn (I tried banks varying 15-25* to find what works best) the nose is quite high at ~74KIAS and ~800fpm, 0 flaps.

How much deference should be given to the inclinometer during this type of flying?
 
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You need more right rudder. The turn just adds to all the other factors.
 
Jaybird180 said:
How much deference should be given to the inclinometer during this type of flying?
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Forget the ball, give the most deference to your ass. :D Once established in a shallow climbing turn with ailerons neutral, you shouldn't generally need any more right rudder than what was required during the climbout before you initiated the turn. Some airplanes will underbank (try to roll out) during shallow turns, which may require you to hold a slight amount of additional rudder in the direction of the turn. During steeper turns, some airplanes have an overbanking tendency, which may require slight rudder in the opposite directon of the turn. As you roll into the turn, you'll need right rudder in addition to what you were already holding for the climbout. Adverse yaw is greater in a climb to the increased AoA, so you'll need more rudder rudder rolling in than you would in straight and level cruise. Doesn't really matter whether you're straight and level, overbanking/underbanking, descending/climbing, or turning left or right...just learn to feel in your seat when you're not coordinated, and add rudder as required. But learn to anticipate the right amount of rudder that'll be needed, depending on your flight condition.
 
Use whatever rudder is required.

Your inclinometer is still a good reference, but you'll find that the more you fly, the less you need to look at the ball.
 
whifferdill said:
Forget the ball, give the most deference to your ass.
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How you sense it (ball or butt) doesn't matter much, but if you're slipping around that climbing right turn, you need more right rudder. Finding the right "feel" for that is a matter of practice, but don't accept any skidding in those turns.
 
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Ron Levy said:
How you sense it (ball or butt) doesn't matter much, but if you're skidding around that climbing right turn, you need more right rudder. Finding the right "feel" for that is a matter of practice, but don't accept any skidding in those turns.
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Actually, if he's in a right turn, and doesn't have enough right rudder, isn't he slipping? Ball is on the inside of the turn.
 
Ron Levy said:
How you sense it (ball or butt) doesn't matter much...
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True, I just feel like the more you can do with precision, with your eyes outside the cockpit, the better you will be in the stick-and-rudder skill department, FWIW.
 
You had to use right rudder in the takeoff and initial straight-ahead climb, and you had to hold it there. In the right turn you'll need more rudder to keep the ball centered. In a left climbing turn, one usually needs to relax the right rudder to keep the ball centered rather than pushing left rudder.

You are fighting P-factor.

Dan
 
Jaybird180 said:
There is a little peculiarity that I noticed on climb out and that is that my climbing right turns were not ball centered. About the best I got them was 1/2 ball deflection to the right - yet glued to that spot. I'm wondering if it's because of an uncoordinated climb out...

How much deference should be given to the inclinometer during this type of flying?
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To find out, tape a yaw string in the center of your cowling. You may find zero yaw with a half ball to the right in a steep climb.

dtuuri
 
To find out, tape a yaw string in the center of your cowling. You may find zero yaw with a half ball to the right in a steep climb.
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That works in a glider. In a powered airplane, spiral slipstream changes the angle of the string.
 
DouglasBader said:
That works in a glider. In a powered airplane, spiral slipstream changes the angle of the string.
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It works good enough. Done it often. Might need to play around with positioning or use two or three yarn tufts to find the sweet spot. You can tape them to the wing beyond the prop arc too, but they're harder to 'read'.

dtuuri
 
Where would you recommend I place it one on my Skyhawk?
 
Jaybird180 said:
Where would you recommend I place it one on my Skyhawk?
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Stick 'em all over--anyplace you're able to see. Do a few stalls, too, the uncoordinated kind, and see what conclusions you can come to. It may be one of the more revealing lessons you've ever done. Watch for buffeting on the trailing wing when stalling in a slip for example. Conventional wisdom would predict the more forward wing should stall first owing to the dihedral effect (greater AoA), but not the case. Try it, you'll like it. ;)

EDIT: Use a masking tape that doesn't pull your paint off. :eek:

dtuuri
 
Jay - Sometimes just a review of the mechanics of a climbing right turn will help: When you're climbing - straight ahead, on the upwind, you should be holding just enough (right) rudder pressure to keep the nose of the airplane from changing direction...while the wings are level. Depending on the type airplane, it could be just an ounce or two. Some airplanes require the pilot to look along side the nose because the nose is so high as to block the horizon.
To start a right turn - in the climb, apply right aileron and additional right rudder simultaneously to establish the bank angle desired, then return the right rudder pressure to the same as it was when you were climbing straight ahead, (while nuetralizing aileron) to roll out, left aileron and release pressure on the right rudder until wings level, then back to the normal climb rudder pressure. I didn't mention back pressure, but that's needed, too. Read Budd Davisson's What's the rudder for?
 
Not sure if this will help, or if it's even a good tip... but this is what I was shown, and what I do from time to time to make sure I am applying the right amount of rudder.

First thing, if you have never done this, is to fly straight towards some landmark on the horizon. Then without any rudder, swing back and forth from left to right about 10-20%. You will notice that the nose of the plane moves all over the place with respect to the point on the horizon. This is because the plane is sliding left and right in the air.

Now do the same with the rudder inputs, and you will see that the nose stays in the same place with respect to the landmark.

The goal when you turn, is to imagine a beam going down the center of the fuselage from engine to tail, and you are trying to rotate around it. For me, when I think of it in those terms, it makes a lot more sense then stepping on the ball.

Sorry if this is basic, and something you already knew, but being this is where new pilots go to learn, it might be useful to someone a little more green then you.
 
Don't these planes have an arc'd tube of water with a ball in it? Why would a bit of string in a slip stream trump that?
 
Captain said:
Don't these planes have an arc'd tube of water with a ball in it? Why would a bit of string in a slip stream trump that?
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Skid balls have flaws, which is the whole reason why glider pilots use yaw strings. Due to momentum, skid balls can give erroneous readings when the airplane is in the process of rolling. Most skid balls aren't mounted on the exact roll axis of the airplane. This produces momentum errors during the roll. When not in the process of rolling, skid balls give good indications. For example, if the ball is mounted on the panel above the exact roll axis, the ball will deflect in the opposite direction of the roll input, even if you are perfectly coordinated.
 
Well I guess there's no way to turn then. Clearly a bit of yarn mounted behind the propeller is the way to go. Ya know, for dead balls accuracy and all...
 
Captain said:
Well I guess there's no way to turn then. Clearly a bit of yarn mounted behind the propeller is the way to go. Ya know, for dead balls accuracy and all...
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I was talking gliders. I overlooked your "slipstream" comment in what I quoted. But in any case, I think a previous poster already mentioned that a yaw string behind a prop is not going to do a lot of good...or at least better than a ball. That is true. You need undisturbed airflow.
 
RoscoeT said:
...a yaw string behind a prop is not going to do a lot of good...or at least better than a ball.
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So, if the ball isn't centered in a steep climb, it means the plane's in sideslip?

Here's a thought experiment to test that theory: Let's say you're pulling your plane off some glare ice on the ramp. You grab the plane's right-hand prop and pull. It slews sideways, right? Ok, so you have a friend push the tail to the plane's left to keep it pointed in the original direction. Now the plane skids obliquely across the ice to your right, though maintaining its heading. Since the ice is level, the ball stays centered despite the skid. If a breeze happens to be blowing parallel to the plane's resultant motion, any yaw string taped to the plane will reveal the true sideslip. So, the ball isn't a reliable indicator of sideslip.

If a row of yaw strings is taped to the cowl behind the prop from left to right, do they all remain parallel? Do they show airflow from left to right or from right to left due to spiraling slipstream? Or do they diverge near the middle? Do they tilt toward each other or away?

It'll be interesting to see Jaybird180's upcoming report.

dtuuri
 
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A garden variety inclinometer (ball) is much better than a yaw string in any single, propeller-driven airplane with the prop in front of the windscreen. In a Velocity it would probably work fine. That said, coordinated flight is best seen out the front windshield. It's okay to glance at the ball once in a while. I suspect concentrating on a yaw string would be no more misguided than the ball.

It seems there is so much mystery concerning coordinated flight...and it's understandable, given the efforts by so many to prevent your learning it well. Oversized instrument panels, bungee-chord rudder aileron inter-connects, aerodynamic efforts by manufacturers to eradicate all adverse yaw all have prevented the students of pedestrian trainers from developing good stick and rudder skills. Most Cessna 150(2) students wouldn't beleive how hard it is to just fly straight and level in a champ or a Cub. A Stearman is not hard to fly, but it makes nosewheel-trained pilots look like complete idiots.
 
Oh my lord. 20 posts and yaw strings and yadda yadda yadda. The answer still is...

More. Right. Rudder.
 
denverpilot said:
Oh my lord. 20 posts and yaw strings and yadda yadda yadda. The answer still is...

More. Right. Rudder.
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Or it could have been a bad inclinometer. The 182N I got my HP in had a bad one. Made me nuts until I realized & accepted it was bad. If you tried to center it, the plane was clearly flying sideways.glad I'm outta that rig.
 
Jaybird180 said:
Or it could have been a bad inclinometer.
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Before you buy a new one, you might consider that you just have a natural feel for the most efficient aerodynamic control configuration.

For those who say yaw strings are no good behind a prop, what about this one? The tufts don't seem affected by "spiraling slipstream" to me:

What about this one. The yaw string seems to be opposite of what you'd expect due to spiraling slipstream (at the top of the window). Note the ball is centered:

dtuuri
 
kgruber said:
I would place it on my right knee, to remind me to "PUSH HARDER!"
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Good answer, I was going to say put it about three feet ahead of the prop. IME a yaw string between the prop and windshield on a single is going to lie considerably WRT slipping/skidding at some power settings (probably worst at low speed / high power combinations). If you put one far enough out on the wing to escape the spiraling slipstream from the prop you will also need a reference mark that lines up with the tail of the string when yaw is zero and even then you'll have a parallax issue if the tail isn't close to the wing surface.

As to the original question, I'd bet that the real issue isn't so much that more rudder is needed in the turn but rather that when climbing at high alpha (requiring lots of right rudder) the pilot's leg is getting tired and the rudder pressure starts falling off about the time a turn is entered. Initiating a turn does require extra pressure while the ailerons are deflected. And that's how I think one should approach this, i.e. when entering a right turn while climbing steeply, one needs to add approximately the same amount of pressure relative to aileron deflection to what's already being applied for the climb attitude/speed as you would when making the same turn at lower alpha. The problem comes from the fact that we generally aren't very good at adding a specific amount of pressure to an existing level as we are when starting with zero pressure.
 
Jaybird180 said:
Or it could have been a bad inclinometer. The 182N I got my HP in had a bad one. Made me nuts until I realized & accepted it was bad. If you tried to center it, the plane was clearly flying sideways.glad I'm outta that rig.
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More likely the instrument wasn't installed level with the airplane. The screw holes in the panel are slotted to allow some rotation of the turn coordinator, and the installer is supposed to level the airplane and then tighten those screws once the instrument has its ball centered.

You may have had a TC with a deformed glass tube in the inclinometer, but it's unlikely. In any case, adjustment or replacement would have fixed it.

Attitude indicators can be off the same way. Makes IFR a pain.

Dan
 
dtuuri said:
Before you buy a new one, you might consider that you just have a natural feel for the most efficient aerodynamic control configuration.

For those who say yaw strings are no good behind a prop, what about this one? The tufts don't seem affected by "spiraling slipstream" to me:What about this one. The yaw string seems to be opposite of what you'd expect due to spiraling slipstream (at the top of the window). Note the ball is centered:dtuuri
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The local flow around the windshield of a tractor-prop airplane is going to be a mess of turbulence. It's not at all the same as the nose of a sailplane. The cowling, cooling inlets, prop, and windshield/glareshield junction angle will all twist the flow into an unreliable thing for yaw-string purposes. Many studies have been done using tuft-testing on the average spam-can, and the results are really enlightening. Some of these airplanes are little better than dump trucks in terms of drag reduction. The Cessna 150, for example, can't even begin to keep up with an Ercoupe or Champ on the same engine.

Dan
 
Dan Thomas said:
The cowling, cooling inlets, prop, and windshield/glareshield junction angle will all twist the flow into an unreliable thing for yaw-string purposes.
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Ever actually tried it? It works well enough for training purposes if you aren't convinced by the videos above. I don't know Nathan Parker, but he's done it and concluded the same as me, "A ball-centered power on stall is in a sideslip to the left; a simple vector analysis can show that this is true, as can a yaw string, which works fairly well behind a propeller, because I have done it."
Maybe not good enough to design airplanes by, but good enough to turn the lights on in a student's mind.

dtuuri
 
dtuuri said:
Ever actually tried it? It works well enough for training purposes if you aren't convinced by the videos above. I don't know Nathan Parker, but he's done it and concluded the same as me, "A ball-centered power on stall is in a sideslip to the left; a simple vector analysis can show that this is true, as can a yaw string, which works fairly well behind a propeller, because I have done it."Maybe not good enough to design airplanes by, but good enough to turn the lights on in a student's mind.

dtuuri
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What I expect you'd find is that the relationship between yaw string angle and inclinometer will vary with thrust and to a lesser extent, airspeed. I could believe that there is a place on the windshield or canopy of some airplanes that minimized this effect but I'll bet it's not all that easy to find that exact location.
 
gismo said:
What I expect you'd find is that the relationship between yaw string angle and inclinometer will vary with thrust and to a lesser extent, airspeed. I could believe that there is a place on the windshield or canopy of some airplanes that minimized this effect but I'll bet it's not all that easy to find that exact location.
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I hope Jaybird180 investigates his question with yaw string/tufting. It would be nice to see a video too (hint, hint). ;) It makes sense to me that an aerodynamically coordinated climb at Vx wouldn't be with the ball centered, so he ought not be too concerned that it's not.

dtuuri
 
I'll let you know if/when I do the experiment and what my findings are. I'm very interested.

However, I wonder about the guy that put the strings on the underside of the airplane. Only way he could see them was by camera....:no:
 
Jaybird180 said:
However, I wonder about the guy that put the strings on the underside of the airplane. Only way he could see them was by camera....:no:
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Gettin' his wife to hold it was pure genius though.

dtuuri
 
Ever actually tried it? It works well enough for training purposes if you aren't convinced by the videos above.
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Sure, It was worthless.

That said, the aircraft on which it's done makes a big difference.

When the windscreen blew out of a Cessna 421 I flew a couple of years ago, I found that there was no airflow into the cockpit through the missing window. In fact, we could stick our hand through the hold and there was no slipstream to speak of. In a case like that, the airflow one might expect would be very different than other airplanes where the airflow is disturbed behind the propeller.

We had a question about porting fuel in a turbine Dromader about ten years ago. The ball could be centered, but the airplane clearly felt out of alignment when the ball was centered. In that condition, fuel transferred through the fuel crossover, and one wing burned down much more quickly. We tried putting a yaw string in front of the cockpit, and in fact tried various attachments from right to the windscreen to attached on a small wire or pole in front of the cockpit. In every case, it was affected by power setting and airspeed, and did nothing to give a useful indication of yaw.

I've applied them on the windscreen for students in the past, but they're fairly useless. Far better to teach the student to reference the ball, and to learn to do it by feel.
 
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