Spinning advice from 1936 [Archive]

Dan Winterland

21st Jun 2020, 07:30

Up to and during WW2, a 'Standard Spin Recovery' was used for all types. It was not long after WW2 that it was acknowledged the results were variable depending on type. And it was the Chipmunk's reluctance to come out of a spin which prompted one of the first variations on the standard recovery. The type acquired the spin strakes and wider chord rudder (and in the UK spinning is prohibited on the type without these) as well as the gradual movement of the control column after a brief pause, which was generally considered to be 2 seconds. And with the introduction of jets with swept wings and greater wing masses, the need for a type specific spin recovery was all the more apparent. It should be made clear that there is no standard spin recovery - the recovery you should use is the one from the types's Pilot Notes/POH/AFM. And no other!

Geriaviator

21st Jun 2020, 10:22

The Chippy's venerable ancestor the Tiger Moth had spin strakes added for the same reason, I think it was before it entered RAF service. I vaguely remember that one European country didn't require them, but another (Holland?) required even bigger strakes.

Pilot DAR

21st Jun 2020, 11:25

Neither Canadian made Tiger Moths I have flown had any spin strakes, I understand it to be a national choice as to require them of not.

Yes, the optimum spin recovery technique will vary by type, and is usually published, even for some non spin approved types. I've never flown a Chipmunk, so have no comment on that type, but I can say that moving the controls forward progressively on some types will delay the recovery. I erred into doing this while spin testing a modified Cessna 206, and had a heck of a ride. For the next spin, after recalling the wording of the POH, I moved the control wheel "briskly" forward following rudder application, and it recovered nicely.
Take training, and read the applicable information for the type.

Fl1ingfrog

21st Jun 2020, 16:20

Darrol Stinton, ‘Flying Qualities and Flight Testing of the Aeroplane’ writes:

“Attempting to make a general rule about spinning is like making a rule about a shark: there is no rule”. Darrol Stinton goes on to outline the recovery from a spin using the term;

Standard Recovery Drill or Procedure

(1) Throttle closed

(2) Ailerons neutral

(3) CHECK that you are in a spin, not a spiral, and also the DIRECTION of rotation.

(4) Stick BACK (i.e. conventional elevator-UP)

(5) Rudder FULL against the indicated direction of turn

(6) PAUSE (say long enough to count one hundred-two hundred-three hundred) allowing the rudder to bite and take effect. THEN:

(7) Move stick progressively FORWARD (elevator NOSE-DOWN) until rotation stops.

(8) EASE OUT of the ensuing dive.

The above is the technique applied when testing an aircraft for certification and for the most part there's little more than lip service to this published in the POH. It is a matter of required compliance on the part of the manufacturer.

I've been concerned for many years with regard to the language used, such as; "briskly", "pause" and "progressively" without any of these words being defined. Briskly could, in the heat of the moment, be applied too much and tip the aircraft inverted. A pause could be anything in a high adrenaline moment and delay the recovery too long similarly the term progressive. Stinton does offer some definitions but few manuals do so.

Prop swinger

21st Jun 2020, 16:32

Looks like he forgot a step:

(7.5) Centralise the rudder.

I also forgot that step in my first spin in a Slingsby Firefly, it very neatly transitioned into a spin in the opposite direction.

djpil

21st Jun 2020, 23:02

Darrol Stinton, ‘Flying Qualities and Flight Testing of the Aeroplane’ writes: ....

(6) PAUSE (say long enough to count one hundred-two hundred-three hundred) allowing the rudder to bite and take effect. THEN:

(7) Move stick progressively FORWARD (elevator NOSE-DOWN) until rotation stops. ......

The above is the technique applied when testing an aircraft for certification and for the most part there's little more than lip service to this published in the POH. It is a matter of required compliance on the part of the manufacturer.

Back in 1936, NACA Tech Note 555 stated:
"The recommended operation of the controls for recovery from a spin, which presupposes that the ailerons are held in neutral throughout the recovery, is as follows:
1. Briskly move the rudder to a position full against the spin.
2. After the lapse of appreciable time, say after at least one-half additional turn has been made, briskly move the elevator to approximately the full down position.
3. Hold these positions of the controls until recovery is effected."

The latest NASA advice is in their TN D-6575 which states:
"It is important to note that when these results were obtained in 1935, the airplanes of that day probably were in the zero loading condition previously discussed and today this recovery technique would apply only for airplanes that have similar loadings. As previously pointed out, the control technique required for spin recovery is primarily dictated by the mass distribution in the airplane. Therefore, for airplanes of different loading conditions, this control technique recommended in 1935 would probably not apply.
....
The mass distribution and the relative density determine the tail configuration requirements and the control technique required for recovery.
....
The rudder is generally the principal recovery control, but for positive (wingheavy) loadings or for recovery during the incipient spin, the elevator can also be an important recovery control and can reduce the rudder power requirements.

Experience has shown, however, that relying on the elevator is dangerous because it might become ineffective for fully developed spins, flat spins, or cases in which the mass distribution has been changed or the center of gravity has been moved behind the normal rearward limit because of changes in loading of the airplane due to growth or operational factors."

I won't go back to the time when Stinton wrote his book but the current FAR 23 Flight Test Guide has: "Recoveries should consist of throttle reduced to idle, ailerons neutralized, full opposite rudder, followed by forward elevator control as required to get the wing out of stall and recover to level flight. For acrobatic category spins, the manufacturer may establish additional recovery procedures, provided they show compliance for those procedures with this section."

I've been concerned for many years with regard to the language used, such as; "briskly", "pause" and "progressively" without any of these words being defined. Briskly could, in the heat of the moment, be applied too much and tip the aircraft inverted. A pause could be anything in a high adrenaline moment and delay the recovery too long similarly the term progressive. Stinton does offer some definitions but few manuals do so.As you can see, NACA explained the "pause"; "briskly" is about the rate of movement not the amount (which must also be specified) so that seems clear to me; "progressively" also seems clear to me. Pilots should know enough theory to understand why those words are used - Australia's CASA has such info required in their Manual of Standards for underpinning knowledge in the spin training.

Genghis the Engineer

21st Jun 2020, 23:13

I had some great arguments with the late, very great Darrol Stinton about spinning from time to time.

Sadly his family last year blocked that book (and his other two) being revised and republished. Their reasoning completely escapes me.

G

megan

21st Jun 2020, 23:37

Pilot DAR

22nd Jun 2020, 02:51

Briskly could, in the heat of the moment, be applied too much and tip the aircraft inverted.

I have found the term very useful in understanding that being unenergetic about forcing the nose down promptly will delay the recovery, which could mean non compliance with the requirement that the single engined plane be recovered in not more than one additional turn. Yes, it is possible to get the nose too far down in some types, at some C of G positions. Too far down, will delay recovery a little, but more importantly, will result in a serious dive during recovery. If, at any point while flying a certified plane, you push the nose down so briskly as to end up unintentionally inverted, you need more basic flying practice.

The recovery of the Cessna Grand Caravan, for example, is vastly different at both C of G extremes, yet Cessna had to publish one procedure which works in all cases, hence "briskly". They condition the term with "... Far enough to break the stall.", and advise the pilot that "Full down elevator will be required at aft center of gravity loadings to assure optimum recoveries.". This, I can assure you is true! I had to briskly apply and then hold full nose down elevator, yet the nose would not go below the horizon for the first half a turn. But, using the Cessna procedure, the plane recovered compliantly, which was what I was testing to confirm.

So after spin testing a dozen or so types, the thing I have learned the most, is to read what the manufacturer published in the flight manual, and do that.

Dan Winterland

22nd Jun 2020, 06:39

Spin strakes were not required on Oz Tigers or Chipmunks, never had issues spinning either myself. Some were of the opinion that the Chippy earned an unsavory reputation because of the length of time it took to recover, instead of waiting for the recovery action to take effect folk would become alarmed that recovery was taking too long and then start trying alternative methods - which would not work. The Tiger spin was rather benign I thought and used to enjoy it, anyone with an insight into why strakes were fitted?

They were fitted soon after the type's introduction after a number of accidents. The issue was determined to be the blanking of the rudder by the tailplane at high angle of attack. The strakes create a vortex which flows over the rudder re-energising the airflow to make it more effective. Other types such as the Tiger and Miles Magister had them. At about the same time, a wide chord rudder was fitted. This was not to improved spin recovery, but to improve handling during aerobatics. But somehow the two got included together in the restriction.

The entry to the spin in those days was usually from the stall, whereas when I was instructing on the RAF's Chippys, we entered from a positively entered semi-flick manoeuvre with full rudder shortly followed by full up elevator applied at 50 knots. This led to a very stable nose down spin which recovered quite rapidly. I flew a number of spin entries from the stall (not all intentional!) which led to a slower, flatter spin which took far longer to recover. I suspect this flatter spin prompted the introduction of the strakes.

Dan Winterland

22nd Jun 2020, 06:57

And as for elevator movement, it really depends on the type. When the Bulldog entered RAF service, it used the Beagle Pup's recovery (Similar to the Chipmunk's) which was reasonable considering it the Bulldog was designed from the Pup. However, they were very different types. the Bulldog was heavier, had more span and that enormous canopy. And several were lost in spinning accidents quite soon after it entered service. It was only after one recovered after the canopy was jettisoned that it was realised that the huge canopy was blanking the rudder. From then, the recovery was changed to a very positive elevator input described as "move the control column firmly forward until the spin stops" which was almost akin to a bunt. This fixed the issue by forcing the rudder into the clear slipstream.

The danger of using the wrong techniques is highlighted by the accident report into a Slingsby Firefly being flown by two current Tucano students where it was postulated they failed to recover from a spin by the application of a technique which wasn't the one recommended in the Firefly POH.

Geriaviator

22nd Jun 2020, 11:56

Fl1ingfrog wrote:
Briskly could, in the heat of the moment, be applied too much and tip the aircraft inverted. A pause could be anything in a high adrenaline moment and delay the recovery too long

Too true! I found my first spin a high adrenaline moment even with a highly experienced ex-CFS instructor beside me (Victa Airtourer, 1965). Of course I knew what was coming but it was still a shock when the aircraft seemed to stop in a gentle turn, lurched sideways and downwards and began spinning. Anyone without spin training has no chance, as seen a couple of years ago when an ex-airline captain with ten times my number of hours spun his C152 off a steep turn with fatal result. About that time, following a fatal stall-spin in a Tiger Moth, someone even suggested in this forum that Tiger Moth aircraft might be inherently dangerous ... too right they are, unless their pilots had been taught to recognise the incipient spin and of course to recover from it. Like Megan I found the TM a docile beast and a superb teacher, as was her successor the Chipmunk.

I remember that individual aircraft can also be different. Tiger Moth DP would recover from a developed spin in three-quarters of a turn, but IT needed seven-eighths. Maybe because DP was rigged to 4.5 degrees incidence, while IT was rigged to the minimum 4 degrees in the hope it would go faster (it didn't). Maybe because DP was built by DH in 1940, while IT was built by Morris Motors in 1941. Of course the old warhorse had so many bits and pieces that inconsistencies were inevitable, a tradition nobly followed by the Tucano according to the rueful engineers on the Mil Aviation forum.

Interesting that Canadian TMs had no strakes, maybe unnecessary because they had canopies over the fiendishly cold open cockpits, increasing the side area?

Pilot DAR

22nd Jun 2020, 13:47

Anyone without spin training has no chance, as seen a couple of years ago when an ex-airline captain with ten times my number of hours spun his C152 off a steep turn with fatal result.

Well, honestly, for a C152, letting go after doing whatever you did to enter a spin, and it will probably find it's way out on its own, with enough altitude. It is noteworthy that aerodynamically, the C152 is identical to the Aerobat versions, which can be recovered from a six turn spin (not as much fun as it sounds). I am aware of fatal spins in C150/152's from altitude, I have never understood how the fatal part was accomplished.

And, recall that the certification standard for single engine planes also requires that it be impossible to create an unrecoverable spin with any use of the controls. So, with enough altitude, and any attempt to either let go, or recover, a 152 should come out.

Though I am a strong proponent of spin training for every pilot, I reluctantly agree that most accidental spins are entered at altitudes too low for a recovery anyway. That fact that a few pilots carelessly spin and die in an unrecoverable situation does not mean that is should not be trained - at least to an awareness level.

I only spun the Canadian Moth a couple of times, about 40 years ago, but nothing stuck in my memory as being unusual, other than we did it on skis rather than wheels. The Moth I check flew a few years ago handled delightfully, though as they were maintenance check flights, post rebuild, I only stalled it, no spins.

Geriaviator

22nd Jun 2020, 15:05

it will probably find it's way out on its own, with enough altitude.
Agreed, but not from 400ft it won't, which was the estimated height from which the 152 was doing photography. I'm well past it now but I still think the benefit of spin training is to raise the awareness level, as you say -- to recognise the situations in which it can occur, and the wing-drop before the spin itself. From fading memory, with full power, lowered nose and rudder an alert pilot might have caught the earlier 150 just in time from that situation but it would have been a close thing.

Our Aerobat frightened its owners one day, fortunately from 4000ft. I thought it seemed reluctant to recover after four turns so we filed a report with the CAA. Darrol Stinton duly arrived complete with parachute and passed it as normal as long as the manufacturer's procedures were followed. A great guy who gave me great encouragement ... he didn't disagree when I said I thought it was a horrible thing anyway, how can you do aerobatics with a steering wheel :oh:

Bergerie1

22nd Jun 2020, 15:17

I think another advantage of having done spin training is to help a pilot to be more tolerant of the 'startle effect'. It is one of the few PPL manouevres (as it used to be) that feel genuinely alarming the first time you experience it.

biscuit74

22nd Jun 2020, 21:17

"I'm well past it now but I still think the benefit of spin training is to raise the awareness level, as you say -- to recognise the situations in which it can occur, and the wing-drop before the spin itself.! (Geriavaitor)

I entirely agree. Spinning itself is fine as a demonstration, but the main point is to get pilots to recognise when the aircraft is about to bite you and spin if you don't do something to sort it !
In sailplanes we fly close to the stall much more frequently than power pilots, so I spent a lot of time with gliding pupils flying near the stall, feeling the buffet and general sloppiness of controls so an almost automatic recovery to normal was likely even when distracted.

(When at height in wave, playing around like that, sometimes letting a wing drop and then picking it up with rudder was a good exercise to help develop confidence and some finesse. Some two seaters can do a fair 'falling leaf' that way. I know picking the wing up with rudder is no longer taught routinely, but at height, in the right conditions, it's still a useful exercise.)

djpil

22nd Jun 2020, 21:46

..... I am aware of fatal spins in C150/152's from altitude, I have never understood . ....
Everyone who spins Cessnas should read this
https://www.kevincfi.com/files/pdf/manuals/Cessna/Spin%20Characteristics%20of%20Cessnas.pdf

Fl1ingfrog

22nd Jun 2020, 23:58

Cessna probably more than any other manufacturer has sought to inform as the above link shared by djpil demonstrates.

In truth very few pilots spin aeroplanes, many do not want to and physiologically find it insufferable. Those of us who spin a lot either as part of aerobatics or as instructors can take things too much for granted and slip into debating the science of it all. This is why pilots such as Gene Beggs and Eric Muller sought to give the ordinary Joe the get out of trouble technique: shove hard against the peddle giving the most resistance and let go of everything else. This works whether your upright or inverted. They never advocated this as a primary technique although many accuse them of doing so.

The Language used in many POH in my view is important. Words in the ear of those experienced pilots who are used to recoveries from unusual attitudes can have a very different meaning in the ear of the pilot not so experienced in all this. The aeroplane does not stall by itself in fact it will not. It is the pilot who stalls and spins not the aeroplane. The "startle" factor followed by disorientation can cause the human to do all sorts of strange things whatever enforced training they may previously have been given. The mandatory PPL spin training given to me for pre 1st solo was probably worthless. At a speed above the stall the pro-spin rudder pedal was jammed hard against the floor followed by the hand control then being yanked back hard against the stop. The nose pitched up pointing vertically towards Mars before going seemingly inverted before the nose dropped and we entered the spin. It was usually necessary to keep pushing the rudder hard to maintain the spin. For me this was all fun and increased my confidence in the aeroplane immensely. For others it was the last time they would fly.

Jhieminga

23rd Jun 2020, 10:01

I vaguely remember that one European country didn't require them, but another (Holland?) required even bigger strakes.
Holland went one step further and deemed this monstrous vertical tail necessary:

https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/930x606/ph_csl_495f58ab6bca6754316fd3181b73dbb5f604711b.jpg

Usually referred to as 'Beddenplank' (bedboard) or 'Fokkerstaart' (Fokker tail), its use is fortunately no longer required. Strakes are acceptable.

jmmoric

23rd Jun 2020, 11:39

Piper 28: Let go of everything.....

djpil

23rd Jun 2020, 12:44

I haven’t done much spinning in PA-28s and it was a long time ago so the information here was a surprise to me https://assets.publishing.service.gov.uk/media/5422f65040f0b6134600063b/dft_avsafety_pdf_501564.pdf

Geriaviator

27th Jun 2020, 15:57

See the airflow over a stalled wing

HERE'S a museum piece which may help today's students who may not have experienced much slow flight: this film was shot in 8mm cine almost 40 yrs ago, transferred from film to VHS, then its cassette lay forgotten in a filing cabinet drawer for another 15 years when we transferred it yet again to DVD and 10 years later to newfangled MPEG4 -- so the quality is terrible! After our discussion of spinning I hope it might be helpful in visualising airflow over the wing, and that hasn't changed since the Wright Brothers.

I'm still impressed by the viceless handling of Piper's oft derided 'Hershey bar' wing, as you can see it had no tendency to drop one side even when the nose was held well up with about 20% power. the nose gently rising and falling with the stick held steady at about three-quarters aft. Maybe someone can provide more info, as I'm decades out of touch with modern instruction methods. I'd love to do it all over again ...

greeners

7th Jul 2020, 18:41

Piper 28: Let go of everything.....

In some aeroplanes - yep.

In all aeroplanes - absolutely not.

Fl1ingfrog

7th Jul 2020, 21:33

There is only one answer: identify whether a spin or spiral dive and recover in accordance with the aircrafts manual. But, how many pilots know the correct recovery or any recognised recovery drill at all: Very few is the truthful answer.

Not to be forgotten is that a modern aircraft will not stall or spin on it's own, it must be caused to do so by the pilot. Only a pilot unfamiliar with stalling or spinning will cause the aircraft to spin unintentionally. The pilot is always the weak link and today's pilot population, in general, is unlikely to ever have spun an aeroplane.

The pilot who is both experienced and current in stall/spin will always be expected to recover very early on at the first signs. The question has to be that if the pilot does not know what it is they have done to cause the aircraft to stall and spin, then it must be best to let go. Eric Mueller's advice in such a circumstance is after letting go shove the pedal giving the most resistance hard to the floor. The current Extra 300 POH advice for the startled pilot is as follows;

'Disorientation spin recovery

If ever disorientation should occur during spins (normal or inverted) one method always works to stop the spin:

1. Power idle

2. Kick rudder to the heavier side

(this will always be against spin direction)

double_barrel

8th Jul 2020, 06:30

I have never experienced a spin, and I feel I should. What sort of response do you think I would get if I asked an instructor to give me a one-off spin session?

(presumably not a good idea to try it alone on the basis of a youtube video!)

Jhieminga

8th Jul 2020, 07:42

They will congratulate you on your good sense.

Bergerie1

8th Jul 2020, 08:00

Don't try it alone, and make sure you learn the differnce between a spin and a spiral dive. Well worth doing. Good luck

Fl1ingfrog

8th Jul 2020, 08:17

Most important when spin training, in support of safety, is to understand each stage of the spin and the various scenarios that can lead to it. The stall/spin recovery is simply unravelling the cause/s in reverse. It should not be an aerobatic exercise. The wham, bam , thank you sam approach does not work. The instructor in my view must always ensure that the pilot is not disorientated nor frightened more than they already will be, for this will be counter productive. Confidence that recovery is always possible is paramount. The unintended stall/spin will always be from a benign entry caused by naive pilot mishandling, it will not be from an extreme attitude. Prevention is always better than the cure.

Frightening and disorientating the student is counter productive. I've lost count of the number of pilots that I've had to spend time with over the decades unravelling the fear they have of stalling, even the word itself. There were (perhaps even now) too many chauvinistic instructors who sought to demonstrate their manhood instead of ensuring that the student has the confidence that the stall can, with certainty, be recovered by doing the correct things.

double_barrel

8th Jul 2020, 09:16

From extensive youtube studies (!) spin training seems to require the student to both enter the spin and recover. Would it not make sense to include a session where an instructor puts it into a spin and asks the student to rescue it? Wouldn't that better teach the student to respond to an unexpected event? Especially as I guess that you quickly learn that if you entered a spin by shoving down your left foot, you need your right boot to recover, thus short cutting a key bit of the problem solving ?

Bergerie1

8th Jul 2020, 09:18

Fl1ingfrog, Totally agree.

db, Yes, at the end of your training you should be able to recover after the instructor has entered the spin and has then asked you to identify the direction and recover. But first you need the step by step approach advocated Fl1ingfrog.

Pilot DAR

8th Jul 2020, 11:20

I also entirely agree with Fl1ingfrog's post.

One of the elements of student learning, which both the student and instructor must understand and compensate for, is the student being so saturated by something new, that their only reaction is "what just happened?", while nothing was learned. This applies to many things which occur in a short period of time, beyond just spinning. However, spin training has been sacrificed in today's training environment, so it'll be the first to be misunderstood.

So the instructor should thoroughly brief, and then enter and recover as opposite as possible to "wham, bam, thank you Sam", brief it and slow it down. The student preparing by watching videos, to get a sense of what to expect, however, the viewer cannot be certain if the video represents a well accomplished spin, or a botch. I've seen lots of botched piloting maneuvers on video, and rarely does the performer say "wow, that was a both, don't do that!". Similar with un mentored use of home computer flight simulators.

It is a surprisingly basic problem with these type of maneuvers that once the pilot has a windshield full of rotating ground, and no horizon, their sense of attitude is not only lost, but worse, there is a sense of urgency from the ground rush. This can promote botched recoveries, as the student will rush a recovery, and secondary stall. Honestly, though I very much promote spin training, if I had to choose only one, between spin or spiral dive training, it'd be spiral dive training. Spiral dives are more likely to be carelessly entered at altitudes from which recovery is possible. It is uncommon for a pilot in "normal" flight to enter an unintentional spin at altitude, but a loss of control at altitude from cruise flight will more likely become a spiral dive than a spin, and the spiral dive is very recoverable early on.

But yes, find a competent instructor, with a spin approved plane, and go get some spin training. You'll know that you're about to get some good training when the session begins with a non rushed briefing, which includes the instructor's hand pointing up and down, and rolling. Follow along with your hand for the practice....

Fl1ingfrog

8th Jul 2020, 12:33

double_barrel to clarify: it is not always the incorrect use of the rudder that can cause the unintentional spin but likely a lack of it.

Pilot Dar as always brings knowledge and common sense to any debate. He has introduced the danger of a spiral dive as a threat. The spiral dive when uncorrected and allowed to develop can be very difficult to get out of in some aircraft particularly those non aerobatic types with a large amount of inbuilt stability. The spiral dive can be just as disorientating as a spin and the inexperienced in such things will have some difficulty in identifying one from the other. When not corrected early the speed may build rapidly to vne: the aeroplane becomes extremely stable, the controls difficult to shift, the risk of over stressing them and a possible failure may dominate the pilots mind.

The difficulty for spiral dive training is that we can take stalling and spinning to the fully developed stage but not the spiral dive recoveries, at or around the aircrafts vne, where it matters and with the apparent control lock.

n5296s

8th Jul 2020, 17:04

It's certainly true that different types recover differently. I've done dozens, maybe over a hundred, spins in the Pitts S2C. It is a pussy cat to recover. Opposite rudder, relax the stick, and it's out in a quarter turn even from a fully developed (>3 turn) spin. But recently I flew the Extra 300 and there you have to do it by the book. Opposite rudder, wait, wait, then stick full forward. It WILL recover if you do it the Pitts way, but only after half a turn or more. It's said that the "let go" technique doesn't work in the Extra, though I haven't tried.

Flat spins (which you should never get into by accident, if you're in CG limits) are a different matter. It's kind of fun to watch the airspeed drop to zero. In the Pitts, a "proper" recovery takes about three turns while you wait for the nose to drop, the airspeed to build and the rudder to get some authority. BUT... you can cheat. If you leave the power in (which you need to get the spin to flatten in the first place) then the propwash gives you enough rudder authority to recover almost instantly.

That works fine... until it doesn't. I got so used to the technique that I routinely recovered spins without pulling power. Then I got into a "knife edge spin" which feels like a spin but isn't really. Nothing I did helped. My instructor pulled the power and we dropped out of it in an instant (it's maintained gyroscopically). Later I got into one again (I have no idea how to enter one deliberately, and neither does my seriously experienced instructor). Following my new training, I instantly pulled the power and recovered. "Oh," he said, "I was hoping you'd hold it for a while and see how it developed".

Pilot DAR

8th Jul 2020, 17:34

In the Pitts, a "proper" recovery takes about three turns while you wait for the nose to drop, the airspeed to build and the rudder to get some authority.

Having not flown a Pitts, I would presume this would be for the uncertified version, as the certified version would have had to demonstrate being recovered from a one turn spin, in one additional turn to be certified at all....

Flat spins (which you should never get into by accident, if you're in CG limits) are a different matter. It's kind of fun to watch the airspeed drop to zero.

Yes, I have experienced these during testing in both the Cessna 206 and 208B. It's a weird combination of benign and terrifying to be looking down at the horizon, with the control wheel pushed all the way in - waiting for something to happen. In each case, it did happen, just the world was going around a bit until it did!

The difficulty for spiral dive training is that we can take stalling and spinning to the fully developed stage but not the spiral dive recoveries, at or around the aircrafts vne, where it matters and with the apparent control lock

Yes, understanding that not only does the speed build up, but also the G, as you pull to recover (not thinking to roll out first). High speed and G together are a very bad place to be - particularly without a G meter!

djpil

8th Jul 2020, 18:44

Having not flown a Pitts, I would presume this would be for the uncertified version, as the certified version would have had to demonstrate being recovered from a one turn spin, in one additional turn to be certified at all....!nope, that’s for normal category aircraft. Per the FAR23 Flight Test Guide:

”(ii) The airplane will recover in not more than 1 1/2 turns after completing application of normal or manufacturer-prescribed recovery controls”

and
”Following abused control usage, reversion to normal pro-spin controls for up to two turns is acceptable, prior to the normal recovery control inputs, which must result in recovery in not more than two turns. In addition, going directly from the control abuse condition to the normal recovery control condition should not render the spin unrecoverable. For example, after evaluating the effect of relaxing the back stick input during the spin, it would be reasonable to expect the pilot to apply normal recovery use of rudder and elevator without first returning to full back stick.”
So, 2 + 2 = 4 turns from when one stops the abused control usage i.e. from when one decides to recover from the flat spin.

plus
”(8) Recovery. Recoveries should consist of throttle reduced to idle, ailerons neutralized, full opposite rudder, followed by forward elevator control as required to get the wing out of stall and recover to level flight. For acrobatic category spins, the manufacturer may establish additional recovery procedures, provided they show compliance for those procedures with this section.” Check the AFM or the cockpit placard for statements something like .... for flat spins use inspin aileron.

The certification test pilot will use exactly the correct technique when demonstrating spin recoveries. I’ve flown most model Pitts (currently own an S-2C) including all of the certified factory production models - they do exactly what is promised.

n5296s

9th Jul 2020, 07:02

Having not flown a Pitts, I would presume this would be for the uncertified version, as the certified version would have had to demonstrate being recovered from a one turn spin, in one additional turn to be certified at all....

Maybe I wasn't very clear. That's from a deliberately flattened spin, using the prop to pick the nose up at the entry and then holding it there with power. I don't know what "abused control usage" means exactly, but you'd really have to be working at it to get there by accident.

From a normal spin - neither flattened nor accelerated - as I said it recovers in about a quarter turn.

The Pitts is truly delightful to fly. Unfortunately though at the end of every flight you have to land it, which is a different story. (Well, you don't HAVE to, but it really pushes the insurance up if you don't).