Spins Video question ?

[PilotDAR]

I had heard of this as internet scuttlebutt some time ago, but never in detail. I shall add it to my file of "they shouldn't have done that". Certainly a good lesson there for those who might be foolishly temped!

Personally, I'm past the point in my flying career where I want to roll planes for no good reason - very certainly someone else's!

[Gene Hasenfus]

Minor detail: Hawker does a very nice (aileron)
roll.

This delivery pilot was practicing snap rolls,
a horse of an entirely different colour.

I somehow doubt that he took the advice in
"Aerodynamics for Naval Aviators" and reduced
his Design G limit to 2/3 for the torsional load,
and calculated his snap roll entry speed based
on that reduced Va.

[Pop n Fresh]

I wonder how that video with the lady doing 57 or whatever number of 152 spins would be received here?

[love2fly14]

The thing about my video, is that the PIC said he was not able to get out of the spin,he quoted "" just rudder did nothing to stop rotation, so after 5 turns had to put it into a spiral to recover (relax back pressure)"

Is this possible ? my instructor says: Power to idle, neutralize ailerons, opposite rudder. This will get you out of a spin. So if the theory is right, it is my believe he was doing something wrong.
Has per how many spins you can do....... I honestly do no see the point. For practice they say 2-3 spins then recover.

[Pop n Fresh]

Go back a page here and read the stuff about, "If the wings remain stalled" More importantly for this conversation, if one wing remains stalled. The rudder might not have sufficient authority to counter a spin.

Out of curiosity are you training in a C-150?

[CFR]

The thing about my video, is that the PIC said he was not able to get out of the spin,he quoted "" just rudder did nothing to stop rotation, so after 5 turns had to put it into a spiral to recover (relax back pressure)"

Is this possible ? my instructor says: Power to idle, neutralize ailerons, opposite rudder. This will get you out of a spin. So if the theory is right, it is my believe he was doing something wrong.
Has per how many spins you can do....... I honestly do no see the point. For practice they say 2-3 spins then recover.

I have not spun a 150 in some time, but from memory it sure seemed the rotations were a little fast. The video does not show the position of the controls, but it may be that there was some aileron introduced into the equation which can accelerate the spin and make recovery a bit more difficult. It is important to neutralize the the ailerons during the recovery. I suspect that in the extended spin that I had, I had inadvertently put in some aileron.

Here is an interesting confession article on spins. There are a number of sources that state a Cessna will recover on its own if you let go of the controls, but I think pilot involvement is best!

http://www.flyingmag.com/pilot-techniqu ... n-recovery

And here is an interesting study into stall/spin accidents

http://www.aopa.org/asf/ntsb/stall_spin.html

[love2fly14]

Go back a page here and read the stuff about, "If the wings remain stalled" More importantly for this conversation, if one wing remains stalled. The rudder might not have sufficient authority to counter a spin.

Out of curiosity are you training in a C-150?

No, using a 172.

[PilotDAR]

my instructor says: Power to idle, neutralize ailerons, opposite rudder. This will get you out of a spin.

None of that mentions unstalling the wing. Doing that is of vital importance. You only entered the spin because you were applying pitch up control input (and some yaw). Stop doing that, and probably introduce some purposeful pitch down control, and you're on the way to a spin recovery. Follow the manufacturer's procedures for spin recovery - they're going to say something to the effect of "lower the nose".

[Gene Hasenfus]

Bill Kershner once opined that the best spin
recovery device, would be a powerful spring
with a boxing glove, mounted on the panel,
which was released by an AOA indicator. It
would punch the pilot unconscious and allow
the aircraft to recover itself from the spin.

See Gene Beggs and Eric Mueller.

1) Power Off
2) Rudder Opposite Yaw
3) Let Go Of Stick

#3 is very important but frequently disregarded
by pilots, who don't want the ailerons and
elevator to trail. Instead, they prefer to keep
hauling back, usually with full aileron deflection.

Pilots don't care, but elevator and aileron (which
they frantically use during the spin) take a very
nice, gentle spin and can make it a very nasty one.

Rather than the silly nose up / hoof a rudder entry
for spin training, I tell people to do a loop with a
soft G entry (eg +2.5 instead of +4). Bonus points
for being a little slow on the entry. We run out of
airspeed on the 45 inverted upline, they don't apply
enough right rudder, slipstream contracts, and we
yaw off and enter the prettiest inverted spin you
ever did see. Did that in a PT-22 Ryan once.

I doubt anyone here remembers the Chino PT-22
accident in 1982 that claimed the "two Jims".

[rxl]

That was my concern at the very beginning of this thread ... there was no mention of the necessity to reduce the angle of attack and get the wing flying again.

[Pop n Fresh]

No, using a 172.

See, these guys are kind of busy but just different models of Cessnas perform quite differently, oddly the numbers make an even bigger difference.

Most of my time is in the nice tame 172N. One nice thing I have learned from reading the board is the 152 is apparently more difficult to land and spins better, that is to say faster and more violently. I'll defer to those with actual experience on type but I suspect the 150 is closer to the 152 than a 172.

I know the 172 is difficult to get a good spin going. I only did it once in my years of trying and it was an accident after a couple of months off. I was fortunate to be with a good enough instructor that after he finished laughing about it he recovered.

[Gene Hasenfus]

reduce the angle of attack

As my father once told me, there is a difference
between scratching your @ss, and tearing yourself
a new one.

For many, many, many aircraft, Beggs/Mueller
works wonderfully, because it stops the pilot from
doing bad things (with elevator and aileron) for a
while, and lets it unspin.

However, there are aircraft (generally low-wing)
which might need a little forward stick after power
off and opposite rudder, to stop the spin ASAP.

Note that above comment about scratching your
@ss, and tearing yourself a new one. Many people
get the "stick forward" religion, and often the cure
is worse than the disease.

It's called "Radius of Gyration". Ever seen a figure
skater, spinning in one place, pull her arms in and
speed up the spin? Conservation of energy means
that as we move mass closer to the center, rotation
must speed up.

And that's what can happen with forward stick in a
spin. Not only do you decrease AOA (and hence
drag) on the wing (a necessary technique for a good
snap roll), by pitching the nose down (in an upright
spin with forward stick, or by pitching the nose down
in an inverted spin with back stick) you are centralizing
mass, and can expect the spin to speed up, or accelerate.

If you really hammer the stick forward fast and
hard enough, you can "cross over" from an upright
spin to an inverted spin. That's really tearing
yourself a new one - unless you have a broken
rudder cable. Miles over the heads of this crowd.

The thing to realize is that spins are a weird little
corner of aviation (aerobatics) that is particularly
badly understood. They are extremely type specific
and loading of the aircraft can have a huge impact.

In fact, you can have two identical-looking (and rigged)
aircraft with identical weight and balance that have
wildly different spin characteristics. One may not even
be recoverable from a spin. The reason for this is
"polar moment of inertia", something understood by
perhaps 0.000001% of all pilots. Integral of radius
squared, dm.

I have resigned myself to the fact that pilots will
never understand even the most basic facts about
spins, and will propogate myth and nonsense forever,
perhaps intentionally.

Here is the best spin recovery placard I have ever
seen, which a student of mine installed on the panel
of his biplane:

[rxl]

Reducing angle of attack to unstall the wing is nonsense???
There is a big difference between releasing back pressure to get BOTH wings flying again and hammering the stick to the forward stop with such force that you end up with a new a-hole.
As with learning any new skill, proper training is key.

I'm really sorry that we are not at your level of understanding.

[Big Pistons Forever]

I have resigned myself to the fact that pilots will
never understand even the most basic facts about
spins, and will propogate myth and nonsense forever,
perhaps intentionally.

FYI it is propagate (ie with an "a") not "propogate"

[cgzro]

.Reducing angle of attack to unstall the wing is nonsense???

No but the asymetric drag is what creates the rotation and its what you usually need to fix first.

Reducing the angle of attack first or at the same time as rudder can have the effect of increasing the spin rate (lowers drag which raises rate and the nose) also in some aircraft the down elevator can actually blank the rudder! in my aircraft fir example the elevator is a wonderful spin snap speed control. The rotation rates goes from mild to wild in a few inches of forward movement. Its great fun !

Every aircraft is different and things change at different density altitudes and cg ranges too.

The best bet is get some training and follow the POH but if you really get confused let go and pushing opposite (heavy) rudder will work better than thrashing about.

[rxl]

But isn't the asymetric drag caused by the stalled wing?

[cgzro]

One or both wings can be stalled in a fully developed spin but the rudder is what is causing the difference in AOA and its that difference you want to get rid of. Changing both wings AOA by some same amount has as primary effect to slow down (up elevator) or speed up the rotation (down elevator). Speeding up has another side effect of raising the nose (flattening the spin).

This can easily be demonstrated by an instructor in an appropriate aircraft and is usually included in upset recovery training which I highly recommend every pilot to take periodically.

[FenderManDan]

Perhaps you will find this video on spin interesting. I am half Slovenian, so a bit biased.

http://youtu.be/9e31q09AksA

[TeePeeCreeper]

Perhaps you will find this video on spin interesting. I am half Slovenian, so a bit biased.

http://youtu.be/9e31q09AksA

Surely this wasn't the spin certification testing right? With 3 POB whom could have been replaced by potato sacks???

All the best,
TPC

[PilotDAR]

Interesting video, it certainly looks like a worthy plane! I'm guessing that's fuel venting from the wingtips during the final few turns? The centrifugal force sent it out to the far ends of the tanks, and out the vents?

[Big Pistons Forever]

No parachutes = Not good idea , back seat pax = Really not good idea , no spin recovery chute = Really truly not good idea........

[FenderManDan]

No parachutes = Not good idea , back seat pax = Really not good idea , no spin recovery chute = Really truly not good idea........

Test pilots upfront, not sure who is at the back. This plane has a BRS.

Interesting video, it certainly looks like a worthy plane! I'm guessing that's fuel venting from the wingtips during the final few turns? The centrifugal force sent it out to the far ends of the tanks, and out the vents?

I saw that too and was wondering. I thought first it could be the moisty air.

[PilotDAR]

I thought first it could be the moisty air

That would not be my first guess, as to have condensation in the wing tip vorticies, you have to be developing considerable lift, which is not really happening in a spin.

[photofly]

Stalled wings generate lift, and since the aircraft is in a steady descent there's the same vertical aerodynamic force (vertical part of lift, vertical part of drag) in a spin as in straight and level flight. So I'd still expect vortices - strong ones, since the airspeed is relatively low and the AoA very high.

[PilotDAR]

I would have thought that the lift being developed was less than for steady flight, as for an aircraft to descend at 1500, or 2000 FPM, the wing must be developing less lift. If, what is seen is a condensed vortex, would it not be larger, and less uniform and straight? It would be emanating from most of the wingtip, rather than a very local point. Though I have many times seen vortecies from a GA aircraft propeller tip, I'm not sure I've ever seen them from GA wingtips. I just did not think that GA aircraft created enough lift differential to do that, particularly in a spin.....