Nimbus 4DT accident 31 July 2000 in Spain.

Hi Chris-

Thanks for herding the discussion toward more science and less emotion.

I apologize to anyone that may have been offended by my comments above re
"clueless". One person wrote a nice note pointing out that the family is
grieving enough without that type of thing.

The point I was trying to make was that those of us that choose to fly these
very long winged aircraft need to be keenly aware of impending problems and
react to them immediately should they begin to develop. If you decide to
thermal in turbulent conditions at just above stall speed then you should be
on edge every second you are doing so and if a gust begins to push you into
a spin or spiral then you should execute your already planned out and
hopefully second nature, correction. If you haven't thought of this plan or
possibility then you have no business flying at those speeds in that
aircraft.

Will having a plan ALWAYS get you out of trouble? No. But as others have
pointed out, in these birds you only have a very short time before there is
not any amount of skill that will save the aircraft.

Sorry to digress Chris.....I'd still really like to hear more about the
aerodynamic reasons that things go awry.....can only help to formulate the
best plan of action!

Casey

On Wed, 22 Jun 2005 12:54:44 UTC, wrote:

I wonder at the thread though. Everyone discussing recognition of a
fully developed spin versus spiral dive.

Isn't it generally more useful to recognize the difference between a
just-developing spin and a just-developing spiral dive?

Which reminds me of Johnston's Test Question for BGA Instructors
Number Three:

"The offical recovery from a stall with wing drop is different from
the official recovery from a spin. At what point do you, personally,
transition from one to the other?"

Ian

--

On Tue, 21 Jun 2005 13:11:53 UTC, Stefan
wrote:

And any pilot who is even
remotely tempted to pull back the stick in a spin is not airworthy.

I suspect that many or all of us are to some extent tempted to do just
that. That's why we need training and practice in the right thing ...

Ian


--

"Ian Johnston" wrote in message
news:dzZo7CxomoOm-pn2-39ddFD9pBSKp@localhost...
On Wed, 22 Jun 2005 12:54:44 UTC, wrote:

I wonder at the thread though. Everyone discussing recognition of a
fully developed spin versus spiral dive.

Isn't it generally more useful to recognize the difference between a
just-developing spin and a just-developing spiral dive?

Which reminds me of Johnston's Test Question for BGA Instructors
Number Three:

"The offical recovery from a stall with wing drop is different from
the official recovery from a spin. At what point do you, personally,
transition from one to the other?"

Ian


As often happens, the BGA comes through with some useful wisdom. Thanks,
Ian.

As for the difference in sensations between an incipient spin and incipient
spiral, the former seems to me to be like an uncommanded yaw and the later
like an uncommanded roll. To me, at least, they clearly say that if the
situation is allowed to continue without intervention, the uncommanded yaw
will become a spin and the uncommanded roll will become a spiral.

I wish I could capture the sensations and record them. They would be very
useful in training.

As for a spinable trainer with similar characteristics, the venerable IS28b2
would do a creditable job of either spin or spiral and build up speed like
crazy in the ensuing dive. It had the requisite large inertia about all
axes. I found it taught me a lot about how to fly a Nimbus.

Bill Daniels

Bill Daniels writes
"The offical recovery from a stall with wing drop is different from
the official recovery from a spin. At what point do you, personally,
transition from one to the other?"

I'm curious. Although in practical terms I'm quite confident (through
practice) that I can tell one from the other and react and recover
accordingly, but how would you phrase the answer to that?

--
Bill Gribble
http://www.scapegoatsanon.demon.co.uk
- Learn from the mistakes of others.
- You won't live long enough to make all of them yourself.

The answer is simple: Stall with a wing drop the first
action is to reduce the AoA, move the stick forward
to unstall the wing.
The action for a spin is: opposite rudder (to stop
the yaw/rotation) and then move the stick progressively
forward to unstall the wing. The recovery from there
is the same.

The important point is that with the wing down stall
the stick forward comes first and rudder may be used
to conteract any yaw present. With the spin the rudder
MUST come first.

In flapped gliders the first action should be flaps
to neutral, well with my flapped glider it should be.



At 16:18 23 June 2005, T O D D P A T T I S T wrote:
Bill Gribble
wrote:

'The offical recovery from a stall with wing drop
is different from
the official recovery from a spin. At what point do
you, personally,
transition from one to the other?'

I'm curious. Although in practical terms I'm quite
confident (through
practice) that I can tell one from the other and react
and recover
accordingly, but how would you phrase the answer to
that?

I'd phrase my answer in terms of pitch down and rotation
angles.

T o d d P a t t i s t - 'WH' Ventus C
(Remove DONTSPAMME from address to email reply.)

On Thu, 23 Jun 2005 16:18:58 UTC, Don Johnstone
wrote:

The answer is simple: Stall with a wing drop the first
action is to reduce the AoA, move the stick forward
to unstall the wing.
The action for a spin is: opposite rudder (to stop
the yaw/rotation) and then move the stick progressively
forward to unstall the wing. The recovery from there
is the same.

Of course. But how far does the wing have to drop - how much does the
glider have to roll at the stall - before you take spin recovery
action rather than stall with wing drop recovery action?

In real life, on the final turn, you have approximately 0.3 seconds to
answer this question ...

ian

The answer is again simple and goes to recognition.
A stall with wing drop is just that and provided action
is taken to solve that problem, unstall the wing, the
a spin will be prevented. A spin is the result of failure
at the first step for whatever reason. Everyone properly
trained will know the difference.

I would suggest that if you get to the point of a fully
developed spin on the final turn the chances of recovery
before the ground gets in the way are very remote,
unless you final turn above 600 feet that is, so you
better recognise and deal with that stall\wing drop.

I have thought about this and decided that if I ever
get to the point where I do get to a fully developed
spin at final turn height I am going to spin in, rather
that than tent peg half way through the recovery. My
philosophy teaches recognition of the approach of the
problem so it can be prevented and this is still not
given sufficient emphasis in training. Yes train people
to recover from fully developed spins but if you do
the job right and train so that they recognise the
approach and take the correct preventative action they
will never need to recover from a spin.

Now here's a question. Given the answer above why when
the wing drops at the start of a take off run (winch
or aero-tow) does everyone almost without exception
try and lift the downgoing wing with aileron?


At 20:42 23 June 2005, Ian Johnston wrote:
On Thu, 23 Jun 2005 16:18:58 UTC, Don Johnstone
wrote:

The answer is simple: Stall with a wing drop the first
action is to reduce the AoA, move the stick forward
to unstall the wing.
The action for a spin is: opposite rudder (to stop
the yaw/rotation) and then move the stick progressively
forward to unstall the wing. The recovery from there
is the same.

Of course. But how far does the wing have to drop -
how much does the
glider have to roll at the stall - before you take
spin recovery
action rather than stall with wing drop recovery action?

In real life, on the final turn, you have approximately
0.3 seconds to
answer this question ...

ian

Ian Johnston wrote:
On Thu, 23 Jun 2005 16:18:58 UTC, Don Johnstone
wrote:


The answer is simple: Stall with a wing drop the first
action is to reduce the AoA, move the stick forward
to unstall the wing.
The action for a spin is: opposite rudder (to stop
the yaw/rotation) and then move the stick progressively
forward to unstall the wing. The recovery from there
is the same.


Of course. But how far does the wing have to drop - how much does the
glider have to roll at the stall - before you take spin recovery
action rather than stall with wing drop recovery action?

In real life, on the final turn, you have approximately 0.3 seconds to
answer this question ...

ian

Has anyone mentioned the yaw string on these wide birds? What's it doing
during incipient diving vs. spinning?

Bob

On Thu, 23 Jun 2005 21:27:25 UTC, Don Johnstone
wrote:

The answer is again simple and goes to recognition.
A stall with wing drop is just that and provided action
is taken to solve that problem, unstall the wing, the
a spin will be prevented. A spin is the result of failure
at the first step for whatever reason. Everyone properly
trained will know the difference.

OK, so how would you described the difference. How far does the wing
have to drop before /you/ use spin recovery rather than stall
recovery? I'm genuinely interested: it's not supposed to be a trick
question in any way.

Ian