Me too (45 degrees was the standard emphasized during my instructors' course).

Of course the simple answer was given very early on. Watch attitude, moniter airspeed, stay co-ordinated and all will be well. There ends the thread!

But no! ... the great thing about these forums is the further debate, and the lessons you can learn from them. It's all very well to then pipe up, complain and say that we're all just going to confuse the poor student, but what does that achieve? We could start a new thread, but then the momentum is lost. Nope, I like the way these things blossom. Hopefully even a student pilot will soon get the basic answer to his/her question, but will often learn more by lstening to the debate of those with more experience.

I'm not sure if this was aimed at my post, but I kind of think it was. If it was, it missed the point. I like Miserlou, started off flying gliders. The over ruddered turn onto finals was a known killer, and therefore well banked (but co-ordinated) turns were drummed into us. Whilst gliders are very different beasts to most light aircraft the principals are the same. When scratching for lift in very tight turns and nibbling the stall buffet, you do learn a lot about the effect of bank and g on stalling. Again, I realise gliders are much more benign than most light aircraft, but again ... the principals are the same!

Bank angle does increase stall speed, higher G does increase stall speed ... but niether cause spins in any greater way than any other stall. If co-ordinated a quick nudge forward will (usually) get the wing biting again. Some aeroplane flik ... but usually there has to be some rudder influence to cause this.

The above may sound Gung Ho .. but that is not the intention. I simply believe .... no, I KNOW, that a skidding turn onto finals is far far more likely to result in a spin than a well banked co-ordinated turn.

Obviously it's far better to judge it all correctly to make sure you roll out nicely on the centre line from a gentle well judged turn, or go around if the picture looks wrong. But in the real world we tend to try and correct our mistakes even if it's not always the wisest thing to do. But if you are to try and correct an over cooked final turn ... use a well banked turn ... not an over ruddered one :uhoh: !


SS

I agree.

Not necessarily. E.g., an SZD-50-3 Puchacz, or an IS-29D2 Lark, is considerably less docile than a 'stable Mabel' airplane like the Cessna 150 or a PA28.

I agree.

Turning downwind to base I take off power while banking to 45 degrees and pull back on the stick to bleed off airspeed to 1.3 - 1.4 VS while staying level.

Then add flap once below the speed to put them out -- newer pilots may want to be wings level before adding to the workload.

Trim on base once flaps down if not before.

Turning base to final -- 45 degrees is good.

If you're undershooting the turn you can take off some bank, but lets not be adding bank past 45.

Turning final, you do not want to be bleeding off airspeed as there's not much to give away; so, it's a descending turn with much less back pressure than turning base.

45 degrees gets the turn done efficiently and gives any X-wind towards the runway less time to blow you past final -- a wider downwind may help in these conditions -- no point making it harder for yourself when it's like that.

Shallow turns lead to the temptation to help it around with rudder and get yourself in a spin.

>What is the best way to ensure that you DON'T inadvertently spin the aircraft on turn from base to finals?

Practice simulated base-final turns at altitude until you learn the feel and what the attitude of the plane looks like at various bank angles / speeds etc. Go with an instructor at first if you're unsure.

Flying by "numbers" is all well and good, but you should be able to fly *without* the aid of the AS indicator (VFR of course), just by using the attitude and feel of the plane.

What plane do you fly? Some, like a 172 are very reluctant, almost impossible to spin, even when you *want* them to :)

Mike

Join long final................

:p

'right-on piloty' and 'grass roots'
 

As well it might be but for good reason. Low houred PPL's are quite capable of understanding the issue here and the importance of angle of attack must be continously emphasized! Such as when increasing the angle of bank also lower the nose. Staring only at the ASI is not the answer to preventing a stall.

The aircraft cannot be spinning when no Yaw is present therefore as some have already stated FLY in BALANCE, ball in the middle!

As I suspect you know, my comments were not aimed at the advice "fly with the ball in the middle". I was questioning the value of going down the route of wing loading and similar...

2D

Gulp.
 

1/(cos45) = 1.41

So, umm, if you fly base at 1.3Vs and then turn finals at 45 AoB... You're cutting it a bit fine - flaps down or not.

I may have got this wrong, but I thought there was more risk from over-ruddering (slipping) then using aileron (cross controlling) as a (flawed)method in correcting the initial error. A skidding turn in comparatively safer.

Of course no-one should argue that a properly balanced turn is the safest.

Miserlou wrote:


STIK,
Quite unusual for most aircraft not to spin one way or the other without dancing on the rudders. If you've time to dance on the rudder you've got time to release the back pressure on the stick which is the actual cause of the circumstances you find yourself in.


Whilst I don't for one second disagree with you, I refer you to my earlier and often reiterated comment; if the aeroplane is flown in a balanced turn it will not spin!

I spin my aeroplane virtually every week, errect multiple rotations, errect accelerated, errect flattened, errect flattened with power, inverted, inverted flattened. Some crazy rides!

Whilst I think that it is an unnecessary burden to stipulate that the PPL fraternity must have spin training, I do believe that it is of serious value.

Several hundred hours ago, I thought I could fly - until I went flying with a chap who made the aeroplane dance and cavort through the sky, we went up and down, round and around and although the aeroplane stall speed was placarded at 63mph, the needle was often sub 40 and yet the aerolane was flying happily.

When we landed I asked a few pertinent questions and then reality dawned - I had a few hundred hours on singles and twins but I couldn't actually fly. All I could do was operate the airframe to a prescribed set of numbers and "drive" it from A to B.

I've spent the last ten years trying to "learn how to fly".

Any info I post on here is just me trying to help others understand the fundamentals.



Stik

I know exactly where you're coming from. I learned to fly gliders first until I could get a power licence so I could fly aeros. Twas before gliders became properly aerobatic.

The problem is that if one is, how should one put it, negligent enough to let the speed fall to such an extent that a stall is iminent, how can one be expected to keep the ball in the middle?
Typically, while holding the aircraft in a full stall, one or the other wing wil drop and be caught on the rudder; one cannot consider this as a stable flight condition.

Also, if you are using the standard Pitts approach technique, I'd like to ask how this is relevant. You may make a perfectly balanced final turn, but then push in the crossed controls to keep the runway in sight.
Of course it's the stick position that's going to kill you.

Brendan showed me some flat turns a few years ago. Picture this. Halfway down the downwind and he simulates an engine failure. Rolls into a steep dive towards the runway, becoming level and parallel to the runway at about 5-10 feet. Then bootful one way, bootful t'other way and flare onto the runway. No messy (and dangerous) low level turns (as long as you've got the speed).

Another lesson learnt!

Long before getting to the base to final turn, make sure the trim is set to the right setting so that the elevator is at neutral load before going in to the turns. Is it flying hands off downwind? If it is, OK, if not, sort it. If the trim is wrong, then that's one more thing that can cause problems, as the loading can end up feeling all wrong. If it's right, then if you let go as such, it's going to come back to something close to where it should be, which may be the difference between comfort and strife.

don't mess with flaps in the turn, get them sorted out wings level, and trim again. That way, you've reduced your work load.

Flying close to the ground is inherently more dangerous than flying at comfortable heights, so the concentration levels have to be higher. If you've passengers on board, shortly before entering the circiuit, politely suggest something like "it's about to get busy now, please don't talk to me unless I say something to you, I need to make sure I don't miss anything from ATC. Thanks." You might need to vary that a little if everyone is on headsets, but I'm sure you get the picture. Then, don't talk to the passengers unless it's something to do with their safety or similar, and concentrate on making sure that it all happens the way it's supposed to.

I think I agreed with you, but not with the terminology. "Over-ruddering" (bottom rudder) is, I think, a skid not a slip. Think if it this way: use top rudder for a slip (ie crossed controls: stick one way, rudder the other). This is safe(r) in a turn to base. The danger comes from a skidding turn. At low height, there can be a psychological tendency to avoid bank, and use rudder not aileron.

Co-ordinated turn: good.
Excess top rudder (slip): OK if you are doing it (side slip) intentionally to lose height, and watching airspeed and attitude.
Excess bottom rudder (skid): bad.

Dusty_B, Yes the load factor can go up to 1.41 which raises the stall speed approx. 19%.

And GA typically flys the approach around 85% of gross which lowers the stall speed 8% yielding a 9% increase in typical GA SE a/c.

stall speed varies with: root(LF) x root(weight/gross)

You can load up the back seats with fellow pilots and go up to 5000 AGL and see just how much biceps is required to stall out of a coordinated descending turn to final.

Yes, it is much easier to stall out at rearward CGs, but will still take considerable muscle in your average standard airworthiness certified spamcan and is much harder with just one or two up front.

I think you're getting yourself muddled here? You could say any out of balance flying is cross controlled. However, a slipping turn is actually a very safe manouver even though you are cross controlled and "over ruddering", whereas a skidding turn (also over ruddering) is dangerous and a true recipy for a spin! What I was trying to illustrate was that by being afraid to bank, you are far more likely to try to turn (perhaps subconciously ... perhaps not!) by adding into-turn rudder and skidding. This is effectively adding yaw in the wrong direction, slowing the already slower inside wing and inviting it to stall first causing rotation and a spin. This may not be the most aerodynamically accurate description of what I'm trying to show, but I hope it gives you the idea. Do not do skidding turns at low level , slipping turns are quite different, but that's been covered loads of times before. Having said the above, I was not suggesting out of balance turns at any point anyway ... what I said was co-ordinated but well banked.

SS

Edited in later ...

FREDAcheck

Sorry, I see you pretty well answered my point to Justinmg in your following post. I really must read subsequent posts before jumping in both feet first :\\

SS

1. Get rid of that instructor for reasons given under 3.

2. a. Fly at correct airspeed, the point Stik makes about the stick position is very true; where I come from the stall is called the 'over-pull'

2.b. Coordinated turns. Forget about top/bottom rudder; skidding slipping just keep that ball in the middle

3. Find yourself a good instructor that can show you the edge of the envelope.

a. Those that have hang-ups about stall/spins are unlikely to be able to give you the appropriate experience.

b. If you have never spun you may not appreciate the potential hazards of them at low altitudes.

Have fun.

Thanks for all the replies -- brilliant. Didn't think there would be so many. Have read them all with interest, and hopefully have taken all comments on board.

Whilst on the subject of slipping turns: I fly a cessna 172, and if high on finals for any reason, often use crossed controls to lose excess height. (Please note that I don't do this in the turn onto finals, but when the wings are level).

I find this effective, but again, is there any danger of spinning?

Also, some say you shouldn't slip a cessna -- others say you shouldn't slip a cessna with any degree of flap on, (which is what I've always been led to believe).

Sorry to sort of hijack my own thread, but do all you guys/girls of much more experience than myself out there have any input on this as well?

Thanks for a very interesting thread so far

G_STRING

It's always interesting reading these discussions and getting various views. I think a lot of the information given to students is based around the most appropriate way of learning, without overloading them.

Its all very well reading of detailed AoA and banking figures when you have hundreds of hours experience, but when learning, something fairly simple is, in my opinion, easier to take in.

When I was learning, the main things I was told at the beginning were:

1) Put flaps down when level - this makes it easier to judge any pitch changes, and if you do have a problem with them going down asynchronously it's easier to recognise and sort out.

2) Watch your airspeed and attitude.

3) Bank at 20-25 degrees, maximum of 30 when turning onto base and final.

4) Keep balanced.

5) If you go through the centreline, keep going and turn back - don't overbank - if it's looking too bad go-around.

If you keep the airspeed at the right amount, and don't bank more than a certain amount while properly balanced, then you won't have a problem with stalling. Once you're lucky enough to have lots of experience then you can start to push the envelope a bit more.

Although I've read many things about the fact that the stalling airspeed changes in various conditions, and I understand what that's about, knowing that for 30 degrees of bank an airspeed of X will keep you away from the stall is useful when setting out.

As an aside, is there a condition of flight that will allow the plane to stall without the stall warner going off? For example, a skidding turn so that the airflow over the stall warner is disrupted?

That's a very interesting question, and one I hadn't thought about before. Most of the aeroplanes/gliders I have flown do not have stall warners anyway, but ....

I would hazard a guess and say that in a skidding turn where the stall warner equipped wing (there's usually only one) is on the outside of the turn, it would be quite possible that the inside wing could stall before the warner (on the outside wing) reaches it's trigger AoA.

There's always a danger, but it is actually not "that" easy to spin from a slipping turn as the yaw is away from the spin. That said don't try to check this out low down :\

SS