INSTRUCTORS AND SPINS

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Hedley
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Post by Hedley » Mon Nov 13, 2006 10:08 am

Suggestion: a typical forced approach that I use on a checkout is to pull the throttle to idle abeam the threshold on downwind, and have the guy land out of it - traffic permitting, of course. This usually only works when you're #1. This is actually an item on the commercial flight test now, IIRC.

Here's another fun emergency procedure .... on downwind, when the guy is looking suspiciously at you and the throttle, and is all primed and ready for the above, is to tell him that the control column just failed - he is going to have to fly the approach and land without it, by using just the power, trim and rudders.

The idiots here will tell you that this training is not applicable to large aircraft, but Al Haynes might disagree, as would the crew of the DHL A300 that had it's flight controls shot out by a SAM over IRAQ.

And that is the point. Anybody can watch an aircraft fly itself. You earn your money as a pilot by doing the right thing, when stuff goes wrong.

Unrelated multiple emergencies are male bovine excrement, but when he gets the hang of the above, tell him that his rudders just failed - all he has is the power and the trim. Now, the donkeys here would tell you that it's time to scream like little girls over the radio that it's time to die, but actually you can yaw an aircraft (and thus roll it, using the dihedral required by certification, which of course allows you to control your heading) by opening the doors :wink:

I'm sure you'd really rather not hear about what I do for unusual attitude recoveries under the hood 8)
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Front.
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Post by Front. » Mon Nov 13, 2006 10:16 pm

lol hedly, when you give responses, i read all of them. They're fulfilled with experience and knowledge.

I should try doing that one time, the CC failure.
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tractor747
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Re: INSTRUCTORS AND SPINS

Post by tractor747 » Fri Apr 20, 2012 4:26 am

I don't know if anyone has dealt with this issue but how do you go about providing spin training in the utility category when the flight instructor weighs like 235 pounds along with the student's weight where you can't do spins in the 152/172 without having like 5 gallons in the fuel tank!

When I was doing my instructor rating me and my class 1 instructor no matter what was never in the utility category.

Do you let your student fly with another "lighter" instructor and let them show and teach the spin? Any suggestions from the pro instructors out there?

thanks
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Re:

Post by AirFrame » Fri Apr 20, 2012 6:28 am

Hedley wrote:Here's another fun emergency procedure .... on downwind, when the guy is looking suspiciously at you and the throttle, and is all primed and ready for the above, is to tell him that the control column just failed - he is going to have to fly the approach and land without it, by using just the power, trim and rudders.
When my instructor did that to me, I asked to confirm that my control column had failed. He said yes, so I said "sit back in your seat" and reached across and used his. It took some mental calibration to get my hand to do the right thing when holding the left side of his yoke, but I landed okay.

Then he made me go up and do it again without touching *either* yoke... :)
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Old Dog Flying
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Re: INSTRUCTORS AND SPINS

Post by Old Dog Flying » Fri Apr 20, 2012 7:40 am

Back in the stone age of tube and rag flying machines with little wheels on the back instead of training wheels under the nose, the spin was taught by every instructor and they were great exerises. And I taught full spins by easing into them gently so as to not scare the hell out of my students and the procedure worked well.

Then my dumb-assed brother-in-law showed me what happens in a Twin Comanche when you get below Vmc with bags of power on the right engine and zero thrust on the left. Instant insanity! An inverted spin from which we needed 8000 ft to recover. He learned another lesson from me when we landed.

The Grumman AA1x series were placarded against intentional spins because they would go into a flat spin due to the fact that the fuel was in the tubular spars and it all went to the tips in a spin causing an unrecoverable situation.

On the other hand, I've probably spun the Tomahawk more than anyone and it was not dangerous as some Cessna instructors would have had you believe. Just fly it right..like every other aircraft out there..read the POH!

Now of course the spin training is considered dangerous and not taught to PPL candidates..mainly because after a generation of poorly trained instructor teaching other poorly trained instructors, students no longer can tell the difference between a spin and a spiral.

Thankfully I no longer instruct in this wonderful world of "glass and plastic" aviation.
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Re: INSTRUCTORS AND SPINS

Post by Colonel Sanders » Fri Apr 20, 2012 10:07 am

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Re:

Post by 767 » Fri Apr 20, 2012 6:57 pm

beechy wrote:Any thoughts on how to present spins to a student who is really scared of them?
Have them do the entry on their own. If they are instructed to "just recover" once the instructor puts the aircraft in the spin, then they will probably always be afraid of spins, and in real life that would be disasterous.
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Re: INSTRUCTORS AND SPINS

Post by 172pilot » Mon Apr 23, 2012 12:53 pm

Are full spins supposed to be a lesson for the CPL now that the flight exam only requires a 1/4 to 1/2 turn before recovery? Can someone comment on whether that is purely incipient or not?
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trey kule
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Re: INSTRUCTORS AND SPINS

Post by trey kule » Mon Apr 23, 2012 3:42 pm

As I am not familiar with flight training standards in Canada anymore, I had to do a bit of research on TCs website.
If I read it correctly, it is not recovering from a spin, but from an incipient spin. (CPL..ex 13)

At 1/4 to 1/2 turn in most trainers this would be called an aggrevated stall or a stall with a wing drop...the word spin would not appear in it. The relative wind is not vertical at this point so the spin is not fully developed.

Perhaps review the flght test guides and you will see the word "incipient" there.

In a normal level flight entry with a 1 kt/sec deceletation, in the typical training aircraft, the relative wind may not become vertical until after several turns, so the spin would be in its incipient stage. Sorry about all the defining condtions but if I dont someone will come on here and point out the relative wind in a snap roll and then post a link to a promotional aerobatic video.

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tester
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Re: INSTRUCTORS AND SPINS

Post by tester » Tue Apr 24, 2012 6:12 am

Guys, I come to this thread late, for which I apologise, but I've been out of touch for a while.

I've done a lot of spinning - and I do mean a lot! As a working test pilot at the UK's Military Flight Test Centre for some 30 years, and flight instructor for even longer, and being involved in the test and evaluation of aircraft ranging from GA types, trainers, and combat aircraft, we did a lot of spin evaluations. I say all this not to claim bragging rights, but to establish that I have a wide range of experience of spinning, testing it and teaching it.

So what's my point? Simply this: just because spinning a 172 during PPL/CPL training is "no big deal", as I think one contributor said, spinning a different type, particularly one that does not have a formal clearance to spin, could be the biggest deal you ever have!

The whole point of the spin test programs I was involved with was to provide advice to aircraft operators about how to avoid spins before they happened and not just how to recover from them. Yes, in a trainer you would also want to spin intentionally and recover, so we would also provide advice on that aspect, but for a combat aircraft or any non-trainer type, you just don't want to enter a spin, because, if you do, you may not be able to recover. In the test program we would have telemetry and a full back-up crew on the ground to help the test pilot and there were times that I really needed the real-time advice they provided, because the test aircraft was not responding to the predicted recovery controls. Fortunately, in my case, the aircraft always eventually did recover and I never had to use the aircraft escape options, but the point is that I had those options if I had needed them. Would you?

For any instructor to go putting an aircraft that is not cleared for spinning into a spin just to impress a student is just plain stupid. Using the classic recovery techniques for the 172 will not necessarily work on other more complex types. Some aircraft are very "spin resistant" and respond readily to the recovery techniques taught during PPL/CPL training, but others may enter a type of spin that would not respond as well, so beware!

So should all professional pilots do advanced spin training in aerobatic aircraft? No! I don't believe that should be mandatory. I think it would be interesting for pilots to experience it, but probably more from the point of view of "upset training" rather than just spinning. What the true professional pilot should do is avoid getting into situations where a spin in likely in the first place! End of rant!
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Re: INSTRUCTORS AND SPINS

Post by 172pilot » Tue Apr 24, 2012 7:01 am

trey kule wrote:As I am not familiar with flight training standards in Canada anymore, I had to do a bit of research on TCs website.
If I read it correctly, it is not recovering from a spin, but from an incipient spin. (CPL..ex 13)

At 1/4 to 1/2 turn in most trainers this would be called an aggrevated stall or a stall with a wing drop...the word spin would not appear in it. The relative wind is not vertical at this point so the spin is not fully developed.

Perhaps review the flght test guides and you will see the word "incipient" there.

In a normal level flight entry with a 1 kt/sec deceletation, in the typical training aircraft, the relative wind may not become vertical until after several turns, so the spin would be in its incipient stage. Sorry about all the defining condtions but if I dont someone will come on here and point out the relative wind in a snap roll and then post a link to a promotional aerobatic video.

.

Correct, TC states it as:
The spin manoeuvre may be requested from various flight conditions. The command to recover can be expected during the incipient stage and after approximately one quarter (1/4) turn of spin rotation.

So my question is, is that not the wing drop and subsequent turn? I was the taught the incipient is the very intial stage of spin entry.
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Re: INSTRUCTORS AND SPINS

Post by trampbike » Tue Apr 24, 2012 12:10 pm

Old Dog Flying wrote: The Grumman AA1x series were placarded against intentional spins because they would go into a flat spin due to the fact that the fuel was in the tubular spars and it all went to the tips in a spin causing an unrecoverable situation.
Probably fun with a spin chute thought...http://www.youtube.com/watch?feature=pl ... 8nE#t=158s
The rate of yawing is impressive.
Edit: Looks like the engine is stopping too. Lack or fuel (all in the wing tips) or airflow?
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Re: INSTRUCTORS AND SPINS

Post by Colonel Sanders » Tue Apr 24, 2012 2:16 pm

the incipient is the very intial stage of spin entry
In my opinion, a full one-turn spin is still incipient, because it
hasn't settled down to auto-rotation yet. Generally around 1.5
turns it will be fully developed, with all of it's wonderful oscillations
and gyrations.

I love spins. I love upright spins. I love inverted spins. I love
flat spins. I love accelerated spins. My personal favorite is the
inverted flat spin, which is an absolute hoot and a complete
pussycat.

I know you guys think I'm really weird, but I'm not the only
one. This is my buddy Spencer. Note the altimeter:



I know some people hate spins, but I guess some people hate
screwing, too. I love screwing, btw.
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Re: INSTRUCTORS AND SPINS

Post by Genetk44 » Tue Apr 24, 2012 2:26 pm

WOW!!!! :shock: :lol: :lol:
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Old Dog Flying
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Re: INSTRUCTORS AND SPINS

Post by Old Dog Flying » Tue Apr 24, 2012 2:58 pm

Trampbike: Fuel starvation caused by fuel forced out to the wing tips uncovering the fuel pickup tubes. A friend survived the flat spin in an AA1x type near Calgary when the schools CFI insisted that any instructor working for him had to spin the aircraft..even though the wee beast had a big placard on the panel ``Ìntentional Spins Prohibited...

The airflow in the flat spin mode is perpendicular to the bottom of the horizontal tail blanking off the rudder which of course makes stopping the autorotation impossible.

Barney
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Re: INSTRUCTORS AND SPINS

Post by YYZSaabGuy » Tue Apr 24, 2012 3:25 pm

Old Dog Flying wrote:The airflow in the flat spin mode is perpendicular to the bottom of the horizontal tail blanking off the rudder which of course makes stopping the autorotation impossible.Barney
That's a very common-sense explanation, Barney: thank you.
Obviously this isn't an issue in an inverted flat spin, per CS's video just above. It does raise the question, though: if you can't stop the autorotation, how on earth does one recover from a flat spin (bearing in mind that Chuck Yeager had a problem with that type of recovery on at least one occasion - cue the very memorable 104 flat spin scene from The Right Stuff)?
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Re: INSTRUCTORS AND SPINS

Post by Old Dog Flying » Tue Apr 24, 2012 5:05 pm

I`m no expert in flat spins in anything but with the Grumman AA1x series, one thought is to slide the canopy back about one foot and hold on. I`ve opened the canopy while my wife was flying and the nose pitched down very rapidly..from level flight...but I have no intention of trying it in a spin!

The canopy can be opened in flight about 6 inches, legally, below 130 mph. Noisy as hell though.

This just might force the nose down causing a change in the relative airflow which just might make the rudder effective enough to recover from the spin.
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Colonel Sanders
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Re: INSTRUCTORS AND SPINS

Post by Colonel Sanders » Tue Apr 24, 2012 5:44 pm

In piston aircraft, we flatten the spin (raise the nose) by
using gyroscopic precession of the propeller. Hence with
a Lycoming or Continental, which rotates clockwise when
viewed from behind, we can only flatten left-yaw upright
spins, or right-yaw inverted spins.

The inverted flat spin is a pussycat, because I can stop it
in 1/4 of a rotation. Thusly, it can be safely entered and
exited at very low altitude. The reason for this is that the
large portion of the top of the rudder is in clean air, and
has lots of authority to stop the yawing of the spin.

However, the upright flat spin must be treated with respect,
and entered with plenty of altitude. As Barney points out,
there is precious little of the rudder underneath the elevator -
it is the only portion in clean air. The portion of the rudder
above the elevator is blanketed and is not very effective.
Because of this, it can take 2 full turns of the upright flat
spin before it exits - with full anti-spin rudder! The problem
is that people are pumped and lose the faith - when they
don't get an instant stoppage of the spin they panic and
try something else. Bad news.

Anyways that's probably too much technical garbage, but
I love inverted flat spins. So do most other airshow pilots.

Note that I would not spin a larger aircraft, because of the
problem of polar moment of inertia.

Technical detail: we can have two identically-appearing aircraft
with the exact same weight and balance, and one is easy to
recover from a spin, and the other cannot be recovered.

How can that be, you ask? You will tell me, "My instructor told
me that if my C of G was in the right place, I was safe". Well,
your instructor hasn't a clue about PMI - integral radius squared
dm probably wasn't mentioned at his puppy mill.

Take a carton of eggs with only 4 eggs in it, in the center slots,
and put your hand on the middle of it on a shiny counter, and
rotate it back and forth as viewed from above. See how easy
it is, to start and stop it?

Now take the 4 eggs and put two at each end, and repeat the
same test. See how much harder it is, to start and stop the
rotation with your wrist? That's because although the W&B is
exactly the same, your PMI is much greater!

An aircraft with all of it's mass concentrated at the center is
going to be easy to start and stop spinning. If it has mass
at the ends, it's going to really want to rotate.

Nobody cares about this kind of thing but me, but ...

There was once a little lady called Kathy Jaffe that flew a
Pitts. She didn't weigh very much, so she put some scuba
weights - not much - in the back of her Pitts. She went up,
did a spin, and rotated right into the ground where she died.

None of you have ever heard of Kathy Jaffe, but she's still
dead.
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Last edited by Colonel Sanders on Tue Apr 24, 2012 5:53 pm, edited 1 time in total.

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Re: INSTRUCTORS AND SPINS

Post by YYZSaabGuy » Tue Apr 24, 2012 5:51 pm

Old Dog and CS, that makes sense - thanks. Here's hoping I never have to try to keep the faith!
Found Yeager's flat spin segment (NF104) in The Right Stuff. I had forgotten what a beautiful airplane the 104 was - and what a terrific movie it is!
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Colonel Sanders
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Re: INSTRUCTORS AND SPINS

Post by Colonel Sanders » Tue Apr 24, 2012 5:56 pm

Please remember how Art Scholl died - in a flat spin
in a Pitts, filming a sequence for Top Gun.

Now children, how would a camera strapped to the
extremity of an aircraft affect it's Polar Moment of
Intertia?

Art is still dead, too.

P.S. The F-104 was an amazing aircraft, when you
consider the dark ages (early 1950's) that it emerged
from. It didn't do very much very well except go very
fast and very high. Like other T-tail aircraft, it suffering
from a pitch-up problem if it was stalled. I would not
recommend stalling or spinning an F-104 if you want
to get a whole lot older. Fortunately the F-104 was
equipped with an equivalent angle of attack indicator
and as long as you kept it less than 17 degrees, it
flew very well - even if you flew it very slowly. It
did a marvellous hammerhead, btw.
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Re: INSTRUCTORS AND SPINS

Post by YYZSaabGuy » Tue Apr 24, 2012 6:06 pm

The RCAF certainly went through its share of 104s back in the day. One of the funniest (in a twisted kind of way) comments to appear on this forum was a contribution on this topic by iflyforpie last April: "Usually the best way to acquire a Starfighter was to buy a small farm in Germany and wait. Maybe fishing nets would work too..."
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Re: INSTRUCTORS AND SPINS

Post by Colonel Sanders » Tue Apr 24, 2012 6:12 pm

iflyforpie is amusing in a left-wing manner, but his grasp of the facts is a little loose in this case, as is typical of left-wing people. The RCAF was not exactly the sole operator of -104's in Europe.

It was actually the Germans who had a horrible problem with the F-104G over in Europe, mostly because their pilots had not gone through the Sabre years in the 1950's that the RCAF did. Even left-wing people can probably recall WWII, and that for a time afterwards, the Germans were not allowed to have a military.

The Germans lacked seasoned wing commanders and group captains to tell their pilots what was safe, and wasn't safe, with horrible consequences.
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Re: INSTRUCTORS AND SPINS

Post by Geo » Tue Apr 24, 2012 7:01 pm

Colonel Sanders wrote: There was once a little lady called Kathy Jaffe that flew a
Pitts. She didn't weigh very much, so she put some scuba
weights - not much - in the back of her Pitts.
Any idea why?

g
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Re: INSTRUCTORS AND SPINS

Post by Old Dog Flying » Tue Apr 24, 2012 8:14 pm

WHY.. CofG might have something to do with it. I was instructing in a Chipmunk (rear seat) and doing a Cuban 8..on the down line while rolling to the upright the damned thing did a 1 and a half snap to the upright then did it again during the last half of the Eight.

I weighed 210 lbs at the time and when I did a weight and balance later, we were at the rearmost of the envelope.
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Re: INSTRUCTORS AND SPINS

Post by cgzro » Tue Apr 24, 2012 8:35 pm

If I remember correctly she was observed by another pilot who stated he felt she had crossed over to inverted.

There was a lot of analysis that went on and some facts came to light which may or may not have been relevant. One was that she added ballast to shift her C of G aft a bit. A small person in a single seat Pitts does have a forward C of G and a Pitts definitely snaps/spins with less effort with a rear C of G but as long as the ballast is added correctly its not an issue. In this case she strapped the weights to the rear of her seat .. which should not have changed her polar moment of inertia much, but is dangerous if it comes loose, which it did not apparently.

There were other discussions about how she was aiming to get a clean spin entry and clean exit. In competition we are judged on 'crispness' of what we do and that usually means you have to be very agressive with the stick. Its possible that she was over agressive in the recovery and in a Pitts/Extra or other aerobatic plane .. if you push the stick forward crisply and slam in the opposite rudder at the wrong time the plane beautifully transitions into an inverted spin which from the outside is of course the same direction but for which your recovery inputs are now inverted spin inputs. The problem is made worse in a bubble canopy plane .. which most aerobatic planes are .. because your tendency is to look up back at the ground.. this gives you the illusion you are rotating in the oposite direction than you get when looking over the nose.

For this reason spin recovery in these kinds of planes is not done aggressively, you usually just give it the required input, especially elevator. No harm with full rudder but full agressive elevator , especially if held is not wise. Upset recovery training also teaches you were to look .. over the nose.. and they also teach go with the flow. Which means to push the rudder to the side you see the flow going. This is because some of these planes rotate so fast (400 degrees a second or so) you don't actually see anything except a blurr and determining rotation direction is confusing. So .. "go with the flow".

The feeling in her case was the she had crossed over from upright to inverted likely by being too agressive. She may have hammered the throttle early too .. something we try to do to minimize energy loss. The lead weights possibly contributing as they would have changed the spin characteristics a bit, but should not have made it unrecoverable as they were attached to the seat back. Had she attached less weight to the tail .. that could have made a big difference to the polar moment of inertia which is probably what CS was alluding to .. but I believe in this case it was not a factor.

Bottom line .. training. She did not have any inverted spin training and these aircraft its pretty important. Her desire to get a crisp entry and exit may have resulted in agressive elevator and power application which if not timed perfectly gets you somewhere mightly confusing the first time you see it.

I did a whack load of spin training in Pitts/Extras etc. before getting mine and even then had a bit of fun the first time I did an inverted spin in it. Every time I recovered she popped immediately into an opposite direction inverted spin. As CS points out the rudder is super effective inverted and recovery only required a quick jab, while upright a more prounounced and longer push is required. Took a couple of rotation direction changes for me to lighten up on the pedals.
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