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Spin Recovery

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Old 30th Mar 2008, 19:42
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In the 1980's film CLOUD DANCER about USA aero comp starring David Carradine, a Pitts crashes for real inverted, the pilot never recovered. It was left in the film at the request of his family.
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Old 30th Mar 2008, 19:55
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BizJetJock

To go back to The Gorilla's question about visually recognising an inverted spin, this can be a problem in straight wing aircraft as well. At least one fatal accident in a Pitts was believed to be caused by the pilot not recognising that it had gone inverted.
Yes it can be a real problem. I've had recoveries from lomcevaks in Pitts S2As go wrong a few times. On 2 occasions ac was still rolling with neutral controls after recovering to down vertical (well below 1,000ft). With T&S fitted, turn needle was a good clue as to erect/inverted; without it, a squeeze of rudder to oppose the roll increased the roll rate so I correctly assumed it was inverted. I defy anyone to visually differentiate between 89 and 91 degrees nose down.

rts
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Old 31st Mar 2008, 03:45
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I got into an inverted spin in a JP5 (hard to imagine how you could do it by accident - but we did!). It felt like an erect spin, but was very nose down and very high rotational - and very disorientating. It was only the T+S which was telling us it that we were inverted that it became clear what we had to do to recover. However, we were both reluctant to believe it. The recovery was immediate when it was initiated, but it took us so long to think about what was going on and what to do about it, we bottomed out below ejection height.

We snagged the aircraft. It turned out one of the wings as out of incidence following an overstress.
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Old 31st Mar 2008, 04:07
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The SSVC film 'The Spin Explained' which was shown to all RAF students on the Tucano explains everything you need to know about the spin including the moments of inertia and B/A ratios.

It's available to purchase, but very expensive. It is however, very good. There is also a much older film "Spinning Modern Aircacraft' which was made in the 60's. It also is good, but not as good as the new film which has some pretty natty (for 1990!) computer graphics.
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Old 20th Apr 2008, 21:07
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Archive

Does anyone know where to find a good piece of archive footage of one of the development Jaguars from BAE Warton (then BAC of course) where Tim Ferguson (Test Pilot) is falling from the sky for a good while in a flat spin, but eventually recovers it without incident. I first saw it on a programme called QED in the 80's. Ive looked all over the net (Youtube etc) but cant find it anywhere.
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Old 21st Apr 2008, 01:42
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Do you mean the one where fuel is spilling out the intakes?
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Old 11th May 2008, 12:39
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I defy anyone to visually differentiate between 89 and 91 degrees nose down.
Bill Finagin, who has done thousands of spins in Pitts and other types, teaches that you need to put the controls to neutral and take ALL power off, which means that you don't need to worry about stick forward or stick back. Look along the nose - then, "nose goes to too much rudder". It's a bit disconcerting when you experience it for the first time, but applying corrective rudder on this basis applies equally well to upright or inverted spins. Once the spin stops, recover.
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Old 13th May 2008, 23:33
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teaches that you need to put the controls to neutral and take ALL power off, which means that you don't need to worry about stick forward or stick back.
i can think of one aerobatic genius that would argue this statement. AC.
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Old 13th May 2008, 23:55
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I'm undoubtedly going to expose my own ignorance here, but.. how can you be in a spin (beyond maybe the initial 2-3 turns when you may be still travelling 'along'), when the aeroplane is 89-91 degrees nose down?

Surely once properly estabished, the overall vector of the plane is vertically down - so in order to be stalled, the wing needs to be at some significant degree from the vertical?

My only experience of an inverted spin was definately rotational, and relatively flat - the horizon line was in clear view. It wasn't in a pitts.
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Old 14th May 2008, 02:19
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An accelerated spin in a Pitts is extremely steep. Perhaps the 89-91 is a bit of an exaggeration but whether upright or inverted it does look vertical.

To add to HappyJack's post - Bill limits that teaching to the Pitts - he calls it FART - refer his article in Sport Aerobatics magazine. He certainly demonstrated it satisfactorily to me. If I was disoriented in a Pitts I'd personally use that rather than Beggs-Mueller now.

(shouldn't we be in a different forum for this discussion the way its going?)
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Old 14th May 2008, 14:24
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Spin recovery

I was told by a good pilot ( then on G.A, now an airliner captain like his father before him, who was also earlier on a fighter pilot ) ;

If in a spin , just MAKE A BIG CHANGE OF INPUT - whether any control surface, airbrake if you have one, or throttle, just make the input change & de-stabilse the spin.

Sounds reasonable to me...
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Old 14th May 2008, 15:36
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In some aeroplanes, that may work - on the other hand, pick the wrong big input and you might just drive it into another (and less recoverable) spin mode. Aileron in a Bulldog springs to mind. Or power in a Tucano left hand erect spin - which tends to stabilise the spin and make recovery much more protracted (when we were doing spinning trials on the Tucano it fairly consistently would NOT recover from that mode with full power and then few more turns once it had been closed).

Actually, that advice comes across to me as downright foolhardy - it might work, if you get lucky, but given that any certified aeroplane will have a tested and approved spin recovery, and any aeroplane has a better chance of responding safely to a "standard spin recovery" than a randomly selected large control input which *might* destabilise the spin, but equally might stabilise it, or disturb it to something nastier than the mode you're in already.

G
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Old 14th May 2008, 18:45
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Absolutely Genghis

That is a terrible bit of advice.
Depending on the dynamics of the aircraft at the time, making a big input change could cause enough excess loading to cause damage / structural failure.... or just expedite your arrival at the scene of the crash.
As you allude to, the development of safe recovery techniques is part of the Flight Test Programme. An expensive part and something we don't do for fun.
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Old 14th May 2008, 20:02
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How can one inadvertedly get into an inverted spin ???

To enter an inverted spin you need to apply FULL FORWARD stick and OPPOSITE foot pressure on rudder (left foot for right spin).

That is a lot of cross controls to apply inadvertedly.

Assuming that you do it fully cosciously on a suitable aircraft, and that you have the situational awareness of what is happening ( comes with practice, the first time everything looks blurred around, the brain just does not follow), you will quiclky notice that you will be positionned OUTSIDE the sense of rotation. i.e. the canopy and pilot will be rotating on the outside.

On an erect spin, the canopy will be INSIDE the rotation during the spin.
Take a model airplane, simulate the manoeuver and you will get the picture.

Then on entry and during rotation on an inverted spin centrifugal forces will also be directed on the outside resulting in malfunctions in the oil/gasoline supply to the engine, if not equipped with fuel injectors and Chrsiten inverted oil supply.

Unconfortable to the pilot and not good for the aircraft engine....Oil sumps lines and carburettors are fed when gravity acts upon them !!!!

So if you have a change get out there, jump in the suitable aircraft with somebody who has practice and go demistify the whole manoeuver !!!
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Old 15th May 2008, 00:11
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Actually I rather disagree with you. The 'standard' entry to a deliberate inverted spin requires full fwd stick and rudder. All any spin requires is asymetric stall - usually yaw and a suitable angle of attack, same as people still manage to spin into the ground, without doing a deliberate spin entry.

for example - here's a little inverted spin scenario:

Rolling off the top of a loop - you're a bit slow, a little hamfisted, and you forget that with negative alpha you're effectively cross controlling as the adverse yaw is reversed... trying to hold the line, and...

Oooppss! the world suddenly rotates..

Hopefully you're smart enough to catch it at the incipient stage, but if you're already head in/singular focus, who knows.

Of course inverted all the anti spin design features like washout are working against you.. so it's arguably even easier to spin inverted.. and in some types, mishandling the ailerons etc can turn an erect spin into an inverted spin.

For that matter, you don't even need rudder to spin - I've seen (deliberate) spin entries off adverse yaw/aileron use at stall (in gliders, granted).

So if you have a change get out there, jump in the suitable aircraft with somebody who has practice and go demistify the whole manoeuver !!!
Call me paranoid, but I did - last week. Damned unpleasant it is too - I enjoy spinning sunny side up, and do basic aeros regularly but the flick-upright-bunt-over is somewhat confronting, and a little disorienting. My lunch *just* about survived.
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Old 15th May 2008, 11:57
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Jaguar Development

I have a video of Jaguar spinning in the early development. I think that it is on a video tape titled "Jaguar/TSR2" (I say 'think' because I haven't watched it for ages). It is produced by Colin Higgs of DD Video, 5 Churchhill Court, 58 Station Road, North Harrow, Middlesex HA2 7SA.
Incidentally I was the Jaguar Development Project Officer (the DEEPO) from 1981 to 1984 running the NAVWASS update programme and the wing strengthening programme.
Hope this helps and I hope I have the right video.
Cheers,
Clive Tudge
Brisbane Australia.
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Old 15th May 2008, 15:43
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Spin recovery

Ghengis,

I will bow to your superior knowledge, I'm not even a PPL but have done hundreds of hours ( at least ) as an aerial photographer, often used as a dumb autopilot, though I did take courses in aeronautics etc.

The pilot who gave me that advice re. " make a large input " impressed me and my dad ( who was a FAA engine fitter on Seafires inc. Salerno then the much more suitable Hellcat, ending 37 years later as a foreman on Harrier 2's ! ).

The reason that pilot impressed us was he did a very strict engine check - almost a 'minor' ! Before we even thought about getting in the thing.

Then again he may have known something we didn't, as 6 weeks later it went in in a big way ( no casualties as far as I know ) through engine failure...

I think the only real answer to spin recovery is a tail ' chute or an ejection seat !

Wasn't there a case of a Trident or similar which deployed the 'anti-spin' 'chute, forgot to jettison it & couldn't understand the lack of 'go' & ended up landing ( safely ) in a field ?!

If no-one believes this, and I don't blame them, I can dig out the details...
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Old 15th May 2008, 19:09
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Hi Clive,
Nice to hear from you - was Ops OS2 under Wg Cdr JS in 82. Remember a few happy times in Paris/Warton. Hope you are fit and well. See you've emigrated to Aus - I'm still in the UK. From memory we didn't expect the T2 to be able to recover from a spin, althought there was a drill for the GR. Spent many hours trying to extend the Jaguar life at various meetings - partly successful until the beast was grounded by the Air Force. Would be interested in a DVD of the video - which was Pete Orme AFAIK.
Colin
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Old 15th May 2008, 20:45
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Mark1234 and markkal please note:
I'm undoubtedly going to expose my own ignorance here, but.. how can you be in a spin (beyond maybe the initial 2-3 turns when you may be still travelling 'along'), when the aeroplane is 89-91 degrees nose down?
If you read my post22 again you'll see that I'm not referring to academic premeditated spin entries, stabilised spins and 'standard' recoveries. In my foolish youth I entered a lomcevak in my Rothman's Pitts S2A from a 45degree climb on knife-edge, and rarely had more than 700ft agl at entry (that's the foolish bit). By the time I'd 'recovered' to the down vertical I was free-falling at idle power with controls neutral and usually between 550 and 600 ft agl. I completed the manoeuvre over 100 times and only 2 went pearshaped after the 'recovery' - the aircraft was rolling without control input, and I assumed that the reason was an auto-rotational condition. The only significance of my remark about 89-91 degrees n/d is that it affects the 'subsequent' recovery actions and with only 2 or 3 seconds to get it right before an 'Oh Christ' pull-out it was nice to have a T&S that never lies about yaw direction.

Double Zero

If in a spin , just MAKE A BIG CHANGE OF INPUT - whether any control surface, airbrake if you have one, or throttle, just make the input change & de-stabilse the spin.
Believe Ghengis and tightflester, NOT your friend. Unless ALL else has failed. My previous post on another thread re spinning an MU2B-40 explains my last remark.

Regards to all,

rts
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Old 15th May 2008, 22:35
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Clive - will you have that video at Watts Bridge next month?
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