Puchaz Spinning thread that might be of interest in light of the recent accident.

Hi All,

A couple of important points regarding this discussion:


(Mark James Boyd) wrote in message news:401eb7ea$1@darkstar...
A spin means both wings have too high AOA and
one wing has more AOA than the other.

If you can change the AOA of both wings so they are unstalled,
using elevator only, and the stress from the now entered spiral
doesn't make the aircraft wings twist and shatter during recovery dive,
then fine, do that.

Attempting an elevator-only recovery (similar to a straight stall
recovery) from a spin, particularly a developed spin, will only serve
to accelerate the rotation; hence, the term "Accelerated Spin."

Doing this in some airplanes will cause them to spin fast enough for
the airframe to vibrate; others may spin fast enough to cause the nose
of the airplane to pop up into an unrecoverable flat spin mode, even
though forward elevator has been applied. If you're strong enough, you
can apply full forward elevator; yet the airlane continues to spin
really, really fast!

Accelerating the rotation aside, applying elevator PRIOR TO the
opposite rudder in airplanes with conventional tail configurations
also serves to blanket additional surface area of the rudder that may
be necessary to upset the dynamics of the spin.

Once the line from "stall" has been crossed to "spin," the order of
recovery inputs becomes critical. The sequence of Rudder--full
opposite FOLLOWED BY Elevator--forward (upright spins) is essential to
maximize the probability of spin recovery in light, general aviation
airplanes (single engine). Reversing that order can seriously alter
spin behavior for the worse and can transform an otherwise recoverable
spin into an unrecoverable spin.


snip

I suspect this is the reasoning behind
the PARE mnemonic, where rudder is used before elevator.

See above.


Power off (for them motorglider thingies)
Aileron Neutral
Rudder Opposite
Elevator forward enough to break stall

Of course, even this mnemonic doesn't work all the
time (sometimes extra power to make the tail surfaces
more effective is better, etc.).

The PARE acronym points to the same tried-and-true (optimized) spin
recovery actions discovered through spin research first in the UK in
1918, later confirmed by NACA in the 1930's, then re-affirmed by NASA
in the 1970-80's. The more things change, the more they stay the
same... And the volumes of reports on spin behavior in light,
single-engine airplanes repeatedly point to these actions.

As for the comment about power -- this is a persistent aviation myth
as it relates to light, single-engine airplanes (which make up more
than 75% of the general aviation fleet, with gliders making up 1%).
The correlation between power and the rate of spin rotation is simple:
less power = slower spinning; more power = spinning faster.

In fact, a small addition of power during a normal spin can increase
the rate of rotation by more than a factor of 2! In some airplanes,
adding power not only speeds up the rotation, but also flattens the
spin. And with all other things being equal, flatter spin attitudes
are more difficult to recover from (take longer, etc.) than steeper
spin attitudes.

To eliminate the aggravating effects associated with power, reduce it
to idle right away as part of the spin recovery process.

Hope this clarifies things a bit,

Rich
http://www.richstowell.com

The paper that Rich wrote on spin training that is posted on his web site is
a must read!

Thank you very much Rich.

--
Gary Boggs
3650 Airport Dr.
Hood River, Oregon, USA
97031-9613
"Rich Stowell" wrote in message
m...
Hi All,

A couple of important points regarding this discussion:


(Mark James Boyd) wrote in message
news:401eb7ea$1@darkstar...
A spin means both wings have too high AOA and
one wing has more AOA than the other.

If you can change the AOA of both wings so they are unstalled,
using elevator only, and the stress from the now entered spiral
doesn't make the aircraft wings twist and shatter during recovery dive,
then fine, do that.

Attempting an elevator-only recovery (similar to a straight stall
recovery) from a spin, particularly a developed spin, will only serve
to accelerate the rotation; hence, the term "Accelerated Spin."

Doing this in some airplanes will cause them to spin fast enough for
the airframe to vibrate; others may spin fast enough to cause the nose
of the airplane to pop up into an unrecoverable flat spin mode, even
though forward elevator has been applied. If you're strong enough, you
can apply full forward elevator; yet the airlane continues to spin
really, really fast!

Accelerating the rotation aside, applying elevator PRIOR TO the
opposite rudder in airplanes with conventional tail configurations
also serves to blanket additional surface area of the rudder that may
be necessary to upset the dynamics of the spin.

Once the line from "stall" has been crossed to "spin," the order of
recovery inputs becomes critical. The sequence of Rudder--full
opposite FOLLOWED BY Elevator--forward (upright spins) is essential to
maximize the probability of spin recovery in light, general aviation
airplanes (single engine). Reversing that order can seriously alter
spin behavior for the worse and can transform an otherwise recoverable
spin into an unrecoverable spin.


snip

I suspect this is the reasoning behind
the PARE mnemonic, where rudder is used before elevator.

See above.


Power off (for them motorglider thingies)
Aileron Neutral
Rudder Opposite
Elevator forward enough to break stall

Of course, even this mnemonic doesn't work all the
time (sometimes extra power to make the tail surfaces
more effective is better, etc.).

The PARE acronym points to the same tried-and-true (optimized) spin
recovery actions discovered through spin research first in the UK in
1918, later confirmed by NACA in the 1930's, then re-affirmed by NASA
in the 1970-80's. The more things change, the more they stay the
same... And the volumes of reports on spin behavior in light,
single-engine airplanes repeatedly point to these actions.

As for the comment about power -- this is a persistent aviation myth
as it relates to light, single-engine airplanes (which make up more
than 75% of the general aviation fleet, with gliders making up 1%).
The correlation between power and the rate of spin rotation is simple:
less power = slower spinning; more power = spinning faster.

In fact, a small addition of power during a normal spin can increase
the rate of rotation by more than a factor of 2! In some airplanes,
adding power not only speeds up the rotation, but also flattens the
spin. And with all other things being equal, flatter spin attitudes
are more difficult to recover from (take longer, etc.) than steeper
spin attitudes.

To eliminate the aggravating effects associated with power, reduce it
to idle right away as part of the spin recovery process.

Hope this clarifies things a bit,

Rich
http://www.richstowell.com

"Gary Boggs" wrote in message ...
The paper that Rich wrote on spin training that is posted on his web site is
a must read!

Thank you very much Rich.

--
Gary Boggs
Hood River, Oregon, USA


You're welcome, Gary! BTW, I'll be giving a seminar on Stalls & Spins
at the NW Aviation Conference in Puyallup, WA on Feb. 21 (4:00 PM) if
anyone's interested...

Rich
http://www.richstowell.com