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Stalls, and turning.


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I'm a great admirer of Bill Whitney's approach to all this. He is very practical. He put out a disc and notes some years ago, which I would recommend to all novice builders and some a bit further on than that for consideration. The aerodynamics are proven and structures analysed thoroughly without you having to have a degree in physics and maths. I don't know whether he still does them but there must be some still around. It stops people having to re-invent the wheel and make the mistakes that someone has already done for you. he made the Whitney Boomerang and did most of the work on the Southern Cross replica, design wise. plus other stuff.. Nev

Yes , very good notes and DVD of his short course. I attended one of his courses, a lot of information to soak up, but absolutely worthwile.

 

 

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Thinking aloud....would a simple forward/back stick position indicator serve as a rudimentary AoA indicator? Perhaps something similar to a Jabiru flap position indicator and have a red line where the stall position is?

Powerin, there was a thread on the worth/value of Lift Reserve Indicators (similar to Angle of Attack Indicators) here:

 

http://www.recreationalflying.com/threads/lift-reserve-indicator.17196/

 

NB: Please refer to this before this link is removed by the moderators (I may think it is on-topic -or a closely related topic- but the mods seem to have different ideas and the moderator's word is law).

 

Correct. We don't have different ideas, just trying to keep everyone on the same field and playing nicely. -- mod

 

 

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Powerin, there was a thread on the worth/value of Lift Reserve Indicators (similar to Angle of Attack Indicators) here:http://www.recreationalflying.com/threads/lift-reserve-indicator.17196/

 

NB: Please refer to this before this link is removed by the moderators (I may think it is on-topic -or a closely related topic- but the mods seem to have different ideas and the moderator's word is law).

Ah yes.....I would have a one of those in a heartbeat (like in your avatar). I think of everything in terms of AoA. But I thought a stick position indicator might be a poor man's LRI.

And yes...the mods are having a sudden awakening 002_wave.gif.62d5c7a07e46b2ae47f4cd2e61a0c301.gif

 

 

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{quote - Bandit12} stalls in a descending turn, with the aircraft out of balance and a more sudden control movement (just like someone who quickly pulled a turn tighter to prevent an overshoot on finals).

 

I know that I didn't learn these from the standard PPL curriculum, and I also question the value of an EMR course 10 years later if you haven't been practicing in the interim. I don't think it is as much a problem that people can get into a bad situation - you can't train people to be able to avoid all possibly bad situations all of the time. But when it happens and you don't have the skills to recognise what is happening and how to get out of it, your odds aren't going to look good.

 

The turn onto final seems to be a common point at which these stall/spins occur.They can be avoided if the pilot just holds the standard turn until the aircraft comes back to the extended runway line.

So I'm curious to hear opinions on this question.

 

Why does it sometimes seem that pilots have a obsession with "not overshooting the turn to final" ?

 

Is there something drilled into students ? If not why are people so bothered by it ?

 

Sure it's nice to be lined up perfectly from two miles out, but the only time when your exact alignment to the runway (in VMC) matters is as you cross the threshold.

 

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Both very GOOD points guys,. . . . . . I don't think that in EVERY case that someone is going to stall just because he "steepened" his turn to avoid overshooting the extended runway centreline, this is usually ( in my experience anyway ) exacerbated by holdiong the secondary effect bank OFF with opposite aileron, BUT, I do agree that if he was too slow in the first instance, then the end result would be very similar. . . .

 

And I agree entirely with both comments re "Why do pilots find it so terrible to overshoot the extended rwy centreline anyway ?? I had this comment after my Brother and I bought a trike for a bit of a giggle, and I was being retrained in the black art of Flexwing flying. . . . the AFI sitting behind me was appalled when I kept missing the centreline, and I said on a couple of occasions,. . ." What's the problem mate ? " with a bit of a wiggle and a squiggle I can get back onto it. ? ? He really wasn't impressed and wantyed me to hit the base to bang on every time.

 

 

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Phil's post (PART 2 - I got interrupted and ran out of edit time ! ! ! )

 

( ? ? ? ) I wonder where this idea came from, maybe the military ? Idunno. It really doesn't make a lot of sense to me though, even though I'd got many years flying experience prior to my trike purchase, this appeared again and again as I found out from other students later on.

 

I truly hope that, after negative comments at many airfields made by obnoxious guys like me and many of my friends that the local instructors might have taken this on board, but I'm not so sure. When you consider the statistics, so many accidents occur at "Coffin Corner" turning onto final at too low an airspeed or out of balance and all screwed up, that I'd have thought commonsense should have shaken up the training industry a bit by now.

 

A millionaire industrialist ( capitalist swine ) that I know who owns a twin Baron, says that since achieving his PPL / IFR and twin rating. . . he "never does circuits or turns final any more" He just points his plane at an airfield and bullies them into allowing him a six or seven mile final, as he was mortified during training of all the horror stories he heard about the dreaded Stall / spin syndrome. . . . I'm beginning to think he wasn't far wrong. . .

 

Phil

 

 

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With more use of parallel runways where there is a separation problem, more emphasis on not going through the centreline might be expected. I think a 'square" circuit might be more likely to produce an overshoot than a racetrack one. The usual cause is a tailwind on base . Nev

 

 

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And I agree entirely with both comments re "Why do pilots find it so terrible to overshoot the extended rwy centreline anyway ?? I had this comment after my Brother and I bought a trike for a bit of a giggle, and I was being retrained in the black art of Flexwing flying. . . . the AFI sitting behind me was appalled when I kept missing the centreline, and I said on a couple of occasions,. . ." What's the problem mate ? " with a bit of a wiggle and a squiggle I can get back onto it. ? ? He really wasn't impressed and wantyed me to hit the base to bang on every time.

Phil,

I agree that it's not the end of the world if you come out of the turn on final and find you are not lined up exactly, but I believe the instructor should be teaching you to put the trike or any other aircraft where you want it to be, part of putting the correct control inputs to achieve the result you want. If he/she accepts mediocrity it is never going to get better once you achieve your certificate.

 

Regards Bill

 

 

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With more use of parallel runways where there is a separation problem, more emphasis on not going through the centreline might be expected. I think a 'square" circuit might be more likely to produce an overshoot than a racetrack one. The usual cause is a tailwind on base . Nev

Yep - round circuits are easier to adjust to align yourself with the extended centreline as all you have to do is vary the angle of bank. A little experience will give you the judgement you need to get it right the vast majority of the time.

 

 

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With more use of parallel runways where there is a separation problem, more emphasis on not going through the centreline might be expected. I think a 'square" circuit might be more likely to produce an overshoot than a racetrack one. The usual cause is a tailwind on base . Nev

I'm a bit surprised at this. I've always found separation at parallel runways is huge - plenty of space to make a mistake.

 

Then I saw the post talking about round circuits ( which I'll assume was oval - I'd faint if they were circular).

 

I'm amazed that instructors haven't jumped in here to point out why we use rectangular circuits; apart from anything else it places each aircraft in the same part of the circuit, doing the same thing at the appropriate time, including radio calls.

 

If for some reason an instructor said it didn't matter, you can turn when you feel like it or do oval circuits, and you find that easy, as against learning how to do a 30 degree turn safely and correctly time after time, in various winds, then one day you are going to breeze into a major circuit with a lot of traffic and you are going to charge straight into the side of a 172 which was ahead of you in the circuit.

 

One of the benefits of a rectangular circuit, having placed your aircraft correctly, is that you have separate and important jobs to do on each leg (when the aircraft will be in different trim configurations on each of those legs)

 

The Military may have reasons for oval circuits but we aren't flying combat aircraft.

 

This thread was instigated by someone falling out of the sky with a turn angle of 60 degrees according to Compulsion, who I believe.

 

My point is that if you learn to turn at 15 degrees on to crosswind and 30 degrees on the other turns, you have a very safe margin if you are hit by a gust, lose your concentration, or mistakenly tighten up because of an overshoot. This was brought home to me even more today when I read about a Baron (twin) pilot who only makes straight in landings because he was scared of all the talk amongst his GA mates about falling out of a turn.

 

Yes, you need to be on the mark in a turn and not lose your concentration, which is a good reason not to get caught up in the last of your downwind checks, or your base descent setup, which you would be doing in an oval turn.

 

One of the reasons this thread has drifted into people trying to get around safe circuit procedure, I think, is the regular posts we read about someone going solo in ten hours, or even five, and it's these shooting stars who never get the instructor supervision on maintaining your circuit control in an adverse wind, adjusting your base leg to reach the correct 500 foot point etc. I certainly have difficulty doing this when I haven't been flying for a while, and I'm sure others do too, but at least I've been trained in the procedures to get the aircraft on a correct final under reasonably adverse conditions.

 

The crucial part of this thread is to concentrate on turning at the safest angle of bank, no matter how much you've screwed up the circuit - better to be yelled at by other aircraft than sitting with the nose pointed at the ground wondering was it rudder or aileron that gets you out of a spin.

 

 

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What are you doing being so slow on base leg that you stall on the turn to final, you should still have enough speed to do a bit steeper turn onto final and then reduce speed. Especially those of you who have flaps.

 

 

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I agree Yenn, but I also understand that not everybody monitors their airspeed perfectly.

 

Personally, I think the routine which I learnt is helpful and all based on Vso (since few of us have an AoA indicator)

 

Downwind/base = 1.4 x Vso

 

Finals = 1.3 x Vso

 

Threshold = 1.2 x Vso

 

That gives you enough speed to make 30 degree turns safely and 45 degree balanced turns with care.

 

If you have flaps, you also have an extra margin when they are deployed as your speeds are based on the clean stall speed.

 

Turbo, let's be clear, it's the combination of speed and angle of bank that does it. If you're flying fast enough, you could turn at 60 degrees safely. You would just need to have enough distance to slow down before landing.

 

 

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Turbo, let's be clear, it's the combination of speed and angle of bank that does it. If you're flying fast enough, you could turn at 60 degrees safely. You would just need to have enough distance to slow down before landing.

I agree Gentreau, but I was just keeping it simple, since there are many posts on here talking about 60 degree turns, and I see many turns in the Moorabbin Training Area between 60 and 90.

 

Unfortunately Yenn came straight in with information about speeds.

 

Before we know it we'll be back to confusion with someone trotting out AOB/Speed/Weight charts again - which no pilot can carry in his head.

 

On speeds, while your rule of thumb speeds may work well on what you've flown, the manufacturer's preferences are found in the POH, and some flying schools/clubs may even add a slight margin to these.

 

 

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Phil,I agree that it's not the end of the world if you come out of the turn on final and find you are not lined up exactly, but I believe the instructor should be teaching you to put the trike or any other aircraft where you want it to be, part of putting the correct control inputs to achieve the result you want. If he/she accepts mediocrity it is never going to get better once you achieve your certificate.

Regards Bill

I don't disagree Bill,

 

I quite agree that this CAN be solved, or at least improved, by training, . . my point was that SOME newish pilots DO tend to over react slavishly in that situation, rather than making steady, balanced adjustments to place the aeroplane back on the desired track. Whether this is because their particular instructor perhaps over emphasised the importance of a "Perfect" turn onto a perfect lineup, or not, I have no idea, but I have seen many instances of this type of over reaction leading to a few interesting moments at low level.

 

Again, it is more than likely due to varying instructional techniques, and the student's own interpretation of same. In my own experience, more students tended to under - anticipate the final turn point especially where any cross wind existed, thereby requiring correction the other way. A small number of them seemed incapable of "Sighting" the runway approach in order to line up with it in a straight line. especially in the case of a larger circuit, and longer final approach. This can be a little confusing to some students, depending upon whether the crab or sideslip method of sidewind / drift correction was used on a final approach.

 

It isn't much use teaching the student to line up a particular rivet on the nose with the runway, if you're "crabbing it in" at various angles in a sidewind.

 

It all makes the world of flight instruction an interesting pastime, as no two students EVER seem to react in the same way ! so the mentor has to dip into his / her bag of different methods of skinning the same cat. I'm glad that I don't do it any more, . . that way, I can criticise all the others ! ! ! Phil.

 

 

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With more use of parallel runways where there is a separation problem, more emphasis on not going through the centreline might be expected. I think a 'square" circuit might be more likely to produce an overshoot than a racetrack one. The usual cause is a tailwind on base . Nev

I agree there too Nev, in the case of parallel runways, then judgement of the final turn point needs a lot more careful consideration - the only problem with this is that good judgement develops only after good training and practice. We don't actually have many small / medium sized airfields in the UK ( other than internationals ) which have a parallel runway setup similar to the Moorabbin layout for instance, and small potatoes private aircraft visitors to these RPT sites are usually discouraged by high levels of public transport movements, plus expensive landing and handling fees. . . but good training and plenty of practice on a single runway situation usually imbues a student with a fairly good idea of how to get it right most of the time, in variable wind conditions.

 

Phil

 

 

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A FWIW on the topic of joining the circuit at an unfamiliar runway - I have taught a fair few people to fly and I can't remember a time where when entering downwind at a new runway the student pilot hasn't been much closer to the runway than at a familiar airport. I don't know why, but everyone did it.

 

My point being that being closer to the runway on downwind means it's more difficult to roll-out onto final without going to larger bank angles, etc.

 

 

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