Spin recovery vs tail design

I would like to solicit comments on the question: Compared to a standard
tail configuration such as a 2-33 or Blanik L-13, does the initiation and
recovery from a spin vary substantially in T-tail (ASK-21 type),
all-flying (Phoebus) or V-tail (HP series) sailplanes? Really look forward
to reading and learning.

On 11 May 2009 16:00:06 GMT, Ron Ogden wrote:

I would like to solicit comments on the question: Compared to a standard
tail configuration such as a 2-33 or Blanik L-13, does the initiation and
recovery from a spin vary substantially in T-tail (ASK-21 type),
all-flying (Phoebus) or V-tail (HP series) sailplanes? Really look forward
to reading and learning.

No significant differences - stick neutral, rudder against direction
of the pin.

Some V-tail gliders require the stick to be pushed fully forward (to
achieve sufficient deflection of the V-tail).

Bye
Andreas

"Andreas Maurer" wrote in message ...
On 11 May 2009 16:00:06 GMT, Ron Ogden wrote:

I would like to solicit comments on the question: Compared to a standard
tail configuration such as a 2-33 or Blanik L-13, does the initiation and
recovery from a spin vary substantially in T-tail (ASK-21 type),
all-flying (Phoebus) or V-tail (HP series) sailplanes? Really look forward
to reading and learning.

No significant differences - stick neutral, rudder against direction
of the pin.

Some V-tail gliders require the stick to be pushed fully forward (to
achieve sufficient deflection of the V-tail).


Ron,

Like Andreas, I find no significant dirrerences. My "V" tail HP-14 doesn't require any special technique.

Wayne
HP-14 "6F"
http://www.soaridaho.com/Schreder

On May 11, 10:24*am, "Wayne Paul" wrote:
"Andreas Maurer" wrote in messagenews:3jjg05hpl4e6hth12gegpo24l4718kv571@4ax .com...
On 11 May 2009 16:00:06 GMT, Ron Ogden wrote:

I would like to solicit comments on the question: Compared to a standard
tail configuration such as a 2-33 or Blanik L-13, does the initiation and
recovery from a spin vary substantially in *T-tail (ASK-21 type),
all-flying (Phoebus) or V-tail (HP series) sailplanes? Really look forward
to reading and learning.

No significant differences - stick neutral, rudder against direction
of the pin.

Some V-tail gliders require the stick to be pushed fully forward (to
achieve sufficient deflection of the V-tail).

Ron,

Like Andreas, I find no significant dirrerences. *My "V" tail HP-14 doesn't require any special technique.

Wayne
HP-14 "6F"http://www.soaridaho.com/Schreder

On May 11, 10:24*am, "Wayne Paul" wrote:
"Andreas Maurer" wrote in messagenews:3jjg05hpl4e6hth12gegpo24l4718kv571@4ax .com...
On 11 May 2009 16:00:06 GMT, Ron Ogden wrote:

I would like to solicit comments on the question: Compared to a standard
tail configuration such as a 2-33 or Blanik L-13, does the initiation and
recovery from a spin vary substantially in *T-tail (ASK-21 type),
all-flying (Phoebus) or V-tail (HP series) sailplanes? Really look forward
to reading and learning.

No significant differences - stick neutral, rudder against direction
of the pin.

Some V-tail gliders require the stick to be pushed fully forward (to
achieve sufficient deflection of the V-tail).

Ron,

Like Andreas, I find no significant dirrerences. *My "V" tail HP-14 doesn't require any special technique.

Wayne
HP-14 "6F"http://www.soaridaho.com/Schreder

I would disagree.

Studies done on exactly this in the early 1960's by NASA at Edwards
AFB did show an effect. To understand the finding, consider how the
airflow moves over the tail at a very high angle of attack as in a
well developed spin.

The flow tends to parallel the swept rudder hinge line on a 2-32 or
2-33. The low mounted tail disrupts or blanks some of the air flowing
toward the rudder. The result is a measurable reduction in rudder
effectiveness which manifests itself in a delayed spin recovery.

Swept tails are undesirable at any airspeed below transonic and are
used merely for styling.

A "T" tail with a vertical rudder hinge is a good solution since the
rudder sees clean airflow and the horizontal acts as an end plate on
the fin and rudder. The one caveat is that the "T" tail shouldn't be
in the wings turbulent wake at any achievable angle of attack - else
you risk a "deep stall" phenomenon.

The second best configuration is a low stab/elevator mounted ahead of
the fin as seen in a BG-12 or K-13 so the free flow has unobstructed
access to the rudder at high angles of attack.

Finally, a separate stabilizer and elevator produces more nose down
moment than an all moving "slab" tail which can stall in it's full-
down position. A stab/elevator can also stall but will nonetheless
produce enough nose down moment to break the stall/spin.

This led to the NACA standard spin recovery technique which called for
anti-spin rudder while holding full up elevator until the auto-
rotation slowed and only then applying down elevator. The reasoning
was that full up elevator exposed more of the rudder to high energy
flow.

On Mon, 11 May 2009 09:53:56 -0700 (PDT), bildan
wrote:


This led to the NACA standard spin recovery technique which called for
anti-spin rudder while holding full up elevator until the auto-
rotation slowed and only then applying down elevator. The reasoning
was that full up elevator exposed more of the rudder to high energy
flow.

Trying this method in nearly any glider is a very safe way to get
killed.

I am pretty sure that most glasss gliders of the least 40 years will
not recover from a spin if the elevator is held fully up during the
recovery attempt - they simply are not going to stop rotation quickly
enough.









Bye
Andreas

On May 11, 4:30*pm, Andreas Maurer wrote:
On Mon, 11 May 2009 09:53:56 -0700 (PDT), bildan
wrote:

This led to the NACA standard spin recovery technique which called for
anti-spin rudder while holding full up elevator until the auto-
rotation slowed and only then applying down elevator. *The reasoning
was that full up elevator exposed more of the rudder to high energy
flow.

Trying this method in nearly any glider is a very safe way to get
killed.

I am pretty sure that most glasss gliders of the least 40 years will
not recover from a spin if the elevator is held fully up during the
recovery attempt - they simply are not going to stop rotation quickly
enough.

Bye
Andreas

Read more carefully. I didn't write anything about trying a recovery
with full up elevator. I wrote "until the auto-rotation slowed and
only then applying down elevator"

In message , Andreas Maurer
writes
On Mon, 11 May 2009 09:53:56 -0700 (PDT), bildan
wrote:


This led to the NACA standard spin recovery technique which called for
anti-spin rudder while holding full up elevator until the auto-
rotation slowed and only then applying down elevator. The reasoning
was that full up elevator exposed more of the rudder to high energy
flow.

Trying this method in nearly any glider is a very safe way to get
killed.

I am pretty sure that most glasss gliders of the least 40 years will
not recover from a spin if the elevator is held fully up during the
recovery attempt - they simply are not going to stop rotation quickly
enough.

I heard about some folks spinning a K21 with the weights kit, and they
nearly ended up bailing out. Later the instructor concluded that they
hadn't been pushing the stick far enough forwards during the
unsuccessful attempts.

--
Surfer!
Email to: ramwater at uk2 dot net

Read the manual for the glider; the spin characteristics were worked out by
a professional test pilo, and the best advice you can get will be in the
operating handbook.

tAt 16:13 11 May 2009, Andreas Maurer wrote:
On 11 May 2009 16:00:06 GMT, Ron Ogden wrote:

I would like to solicit comments on the question: Compared to a
standard
tail configuration such as a 2-33 or Blanik L-13, does the initiation
and
recovery from a spin vary substantially in T-tail (ASK-21 type),
all-flying (Phoebus) or V-tail (HP series) sailplanes? Really look
forward
to reading and learning.

No significant differences - stick neutral, rudder against direction
of the pin.

Some V-tail gliders require the stick to be pushed fully forward (to
achieve sufficient deflection of the V-tail).

Bye
Andreas

Read the manual for the glider; the spin characteristics were worked out by
a professional test pilot, and the best advice you can get will be in the
operating handbook.

Great advice, although with my Sisu 1a no such manual exists... that
said, it had a very well designed V tail that required no special
considerations for initiating or recovering from spins, and there were
no other indications in flight that would indicate it's unconventional
configuration. Spin recovery was quicker with the flaps retracted
though, so that too was a consideration, although probably not one
specific to V tails.

I personally enjoy spinning ships, and like to do what I call 'spot
spinning', meaning coming out on predetermined headings after a
predetermined number of revolutions... WEEE great fun!! Haven't got
into inverted spins yet though...

-Paul