CFI oral intel

Vaughn Simon wrote:
> "Robert M. Gary" <N7093v@**********> wrote in message
> news:887614a4-12cf-493f-98fa-0834d3f39452@i36g2000prf.************.com...
> On May 30, 9:00 am, "F. Baum" <kkw...@yahoo.com> wrote:
>
> I don't think a 5 hour oral is odd at all for the CFI exam. I know
> some PI/DE's schedule a full day for the oral and another day for
> flying. Do you really know any initial CFI oral that lasted minutes?
>
> Mine was something less than two hours. The whole thing was probably half a
> day, but that included the paperwork. (Mine was unusual in that it was with a
> designee.)
>
> Vaughn
>
>
Mine was about two hours for the oral.

--
Dudley Henriques

On Mon, 02 Jun 2008 23:30:12 -0500, Michael Ash <mike@mikeash.com>
wrote:

>In rec.aviation.student Gezellig <nokonihi@**********> wrote:
>> On Fri, 30 May 2008 01:20:04 -0500, Michael Ash wrote:
>>
>>> Joking aside, if your straps were loose enough that you could slump
>>> forward, that *would* affect your CG which would in turn affect your
>>> trimmed airspeed.
>>>
>>> There's another issue that I just thought of that I don't think anyone has
>>> mentioned yet, though. Won't you get into a graveyard (bad terminology for
>>> this scenario, as you're already dead) spiral? After all, if you could
>>> stay straight and level just by taking your hands off the controls you
>>> wouldn't need to fear IMC with no gyroscopic instruments. So it seems that
>>> if you start high enough, the correct answer to this question would be
>>> whatever the terminal velocity of your fuselage is without its wings. Am I
>>> off base here?
>>
>> You fly until gassless, stall, nose down, then descend too rapidly,
>> striking the ground with the wings ripped off. Works for me.
>
>You don't stall, because when the engine quits the airplane will start to
>descend, maintaining approximately the original airspeed.

Unless the autopilot is engaged..............

Below is a very well done white paper on stability by Russel Williams
that addresses much of what we have been discussing.

The long and short of it in my opinion is that positive lateral
stability is present in GA airplanes and they will tend to recover from
the sideslip coupling. Your key point addresses potential disturbances
that can indeed exceed this recovery tendency.
I agree totally with you that such a disturbance can exceed positive
stability tendencies if strong enough.

I believe you will find this paper interesting and informational.


http--soar.wichita.edu-dspace-bitstream-10057-754-1-t05045.pdf.webloc



--
Dudley Henriques

Michael Ash <mike@mikeash.com> wrote in
news:1212572312.616709@web1.segnet.com:

> In rec.aviation.student Gezellig <geezellig@**********> wrote:
>> Michael Ash pretended :
>>> In rec.aviation.student Gezellig <nokonihi@**********> wrote:
>>>> On Fri, 30 May 2008 01:20:04 -0500, Michael Ash wrote:
>>>>
>>>>> Joking aside, if your straps were loose enough that you could
>>>>> slump forward, that *would* affect your CG which would in turn
>>>>> affect your trimmed airspeed.
>>>>>
>>>>> There's another issue that I just thought of that I don't think
>>>>> anyone has mentioned yet, though. Won't you get into a graveyard
>>>>> (bad terminology for this scenario, as you're already dead)
>>>>> spiral? After all, if you could stay straight and level just by
>>>>> taking your hands off the controls you wouldn't need to fear IMC
>>>>> with no gyroscopic instruments. So it seems that if you start high
>>>>> enough, the correct answer to this question would be whatever the
>>>>> terminal velocity of your fuselage is without its wings. Am I
>>>>> off base here?
>>>>
>>>> You fly until gassless, stall, nose down, then descend too rapidly,
>>>> striking the ground with the wings ripped off. Works for me.
>>
>>> You don't stall, because when the engine quits the airplane will
>>> start to descend, maintaining approximately the original airspeed.
>>
>> At what point do you expect to lose the wings via "the correct answer
>> to this question would be whatever the terminal velocity of your
>> fuselage is without its wings."?
>
> If you enter a spiral dive as I surmised, the wings fall off either
> when you exceed Vne or when you exceed the maximum loading the wings
> can support, whichever comes first. However it would seem that whether
> this happens or not will depend on the airplane in question.

Well, the wings won't come off as you exceed VNE. You have a good 10% on
top of that before anything will happen.
Something nasty will at the load limit, though. Not the published one,
of course, but at 50% over that. At the published load limit you are
guarunteed that the airplane will not permanently deform. 50% over that
you're guaunteed it will remain in one piece. Over that you're on your
own. It;s not quite as tidy as all that, though and with most light
planes it's probably flutter that's going to pull it apart and that will
probably be brought on by a combination of load and speed. This is not
to say it's safe to operate at or near the red line or load limit.
It isn't.



Bertie
>

BTW, just about any old ragbag will fly around like a free flight airplane
until they run out of gas. For that matter so will most cessnas and the
like.



Bertie

On Jun 4, 9:38 pm, Michael Ash <m...@mikeash.com> wrote:
> In rec.aviation.student Gezellig <geezel...@**********> wrote:
>
>
>
>
>
> > Michael Ash pretended :
> >> In rec.aviation.student Gezellig <nokon...@**********> wrote:
> >>> On Fri, 30 May 2008 01:20:04 -0500, Michael Ash wrote:
>
> >>>> Joking aside, if your straps were loose enough that you could slump
> >>>> forward, that *would* affect your CG which would in turn affect your
> >>>> trimmed airspeed.
>
> >>>> There's another issue that I just thought of that I don't think anyone has
> >>>> mentioned yet, though. Won't you get into a graveyard (bad terminology for
> >>>> this scenario, as you're already dead) spiral? After all, if you could
> >>>> stay straight and level just by taking your hands off the controls you
> >>>> wouldn't need to fear IMC with no gyroscopic instruments. So it seems that
> >>>> if you start high enough, the correct answer to this question would be
> >>>> whatever the terminal velocity of your fuselage is without its wings. Am I
> >>>> off base here?
>
> >>> You fly until gassless, stall, nose down, then descend too rapidly,
> >>> striking the ground with the wings ripped off. Works for me.
>
> >> You don't stall, because when the engine quits the airplane will start to
> >> descend, maintaining approximately the original airspeed.
>
> > At what point do you expect to lose the wings via "the correct answer
> > to this question would be whatever the terminal velocity of your
> > fuselage is without its wings."?
>
> If you enter a spiral dive as I surmised, the wings fall off either when
> you exceed Vne or when you exceed the maximum loading the wings can
> support, whichever comes first. However it would seem that whether this
> happens or not will depend on the airplane in question.
>

If the plane is in a steady dive at 2x VNE what is the wing loading?
VNE may be set by srface instability (flutter) or perhaps engine
overspeed but is not set by wing loading -that is Va -at least that's
my understanding.

Cheers

More_Flaps <Moreflaps@**********> wrote in
news:b1345c9e-2b51-4f40-a7f8-7724677a5446@i18g2000prn.************.com:

> On Jun 4, 9:38 pm, Michael Ash <m...@mikeash.com> wrote:
>> In rec.aviation.student Gezellig <geezel...@**********> wrote:
>>
>>
>>
>>
>>
>> > Michael Ash pretended :
>> >> In rec.aviation.student Gezellig <nokon...@**********> wrote:
>> >>> On Fri, 30 May 2008 01:20:04 -0500, Michael Ash wrote:
>>
>> >>>> Joking aside, if your straps were loose enough that you could
>> >>>> slump forward, that *would* affect your CG which would in turn
>> >>>> affect your trimmed airspeed.
>>
>> >>>> There's another issue that I just thought of that I don't think
>> >>>> anyon
> e has
>> >>>> mentioned yet, though. Won't you get into a graveyard (bad
>> >>>> terminolog
> y for
>> >>>> this scenario, as you're already dead) spiral? After all, if you
>> >>>> coul
> d
>> >>>> stay straight and level just by taking your hands off the
>> >>>> controls yo
> u
>> >>>> wouldn't need to fear IMC with no gyroscopic instruments. So it
>> >>>> seems
> that
>> >>>> if you start high enough, the correct answer to this question
>> >>>> would b
> e
>> >>>> whatever the terminal velocity of your fuselage is without its
>> >>>> wings.
> Am I
>> >>>> off base here?
>>
>> >>> You fly until gassless, stall, nose down, then descend too
>> >>> rapidly, striking the ground with the wings ripped off. Works for
>> >>> me.
>>
>> >> You don't stall, because when the engine quits the airplane will
>> >> start
> to
>> >> descend, maintaining approximately the original airspeed.
>>
>> > At what point do you expect to lose the wings via "the correct
>> > answer to this question would be whatever the terminal velocity of
>> > your fuselage is without its wings."?
>>
>> If you enter a spiral dive as I surmised, the wings fall off either
>> when you exceed Vne or when you exceed the maximum loading the wings
>> can support, whichever comes first. However it would seem that
>> whether this happens or not will depend on the airplane in question.
>>
>
> If the plane is in a steady dive at 2x VNE what is the wing loading?
> VNE may be set by srface instability (flutter) or perhaps engine
> overspeed but is not set by wing loading -that is Va -at least that's
> my understanding.
>

That's right, but the tendency to flutter is exacerbated by load. So, if
you're over redline and you're loading the wing, flutter will occur at a
lower speed than if that surface was unloaded. Flutter is all to do with
the elastic properties of the flight surface, so if it's loaded up
you're exciting the cycle.



Bertie

Michael wrote:
> I recall one particular sad incident where a Pilatus Porter dropping
> jumpers lost the yoke - it literally came off in the pilot's hands.
> The pilot elected to bail out (which was, IMO, the wrong call - a
> plane can be landed with rudder, throttle, and trim). His parachute
> malfunctioned, and the pilot died.

I'll file this under: "You know you're having a bad day when..."

Hilton

Michael Ash wrote:
> In a steady *spiral* dive the wing loading will be determined by your bank
> angle.

Can you prove that? (mathematically or non-mathematically)

Hilton

On Jun 4, 10:42 am, Dudley Henriques <dhenriq...@rcn.com> wrote:
> Below is a very well done white paper on stability by Russel Williams
> that addresses much of what we have been discussing.

The link does not work, and I can't find it through google. Do you
have another link?

> The long and short of it in my opinion is that positive lateral
> stability is present in GA airplanes

As lond as you mean static stability, then yes - weak positive lateral
stability is present in most non-aerobatic (and a few aerobatic) GA
airplanes as long as the displacement from wings-level is small.

> and they will tend to recover from
> the sideslip coupling.

Again, as long as the displacement is small and the lateral trim is
near-perfect.

> Your key point addresses potential disturbances
> that can indeed exceed this recovery tendency.
> I agree totally with you that such a disturbance can exceed positive
> stability tendencies if strong enough.

And I guess my point is that in most cases, these disturbances will be
strong enough, especially in an airplane that can cruise 110 kt. I
think this is something easy enough to prove in most cases. For those
playing along on the home game, try this next time you fly. Do this on
the smoothest possible day you can get.

Set up the plane in cruise at 110 kt. Trim it out as well as you can,
both in pitch, and, if aileron and/or rudder trim is available, in
roll as well. My guess is that most airplanes that can cruise 110 kt
will have aileron or rudder trim available - I can't off the top of my
head think of any certificated exceptions to this (I am sure there is
one).

Let go of the controls. All of them - hands off the yoke/stick and
feet off the rudders - and just sit there. Note how long it takes to
exceed 25 degrees of bank or change heading by 90 degrees.

If in 15 minutes that doesn't happen, smoothly bring the throttle to
idle to simulate fuel exhaustion. Let the plane descend 2000 ft or so
(use carb heat if appropriate). Now see if you are still within 25
degrees of wings level. The reason this matters - generally the
engine is offset just enough that at cruise, you should need no
rudder. On takeoff the left-turning (for CW engines) tendencies are
increased, so you need some right rudder. On a power-off descent, you
need some left rudder. Yaw and roll are coupled. So even if you were
in perfect lateral trim before you went to idle, you're not anymore.

Now I'm willing to bet that at least 9 out of 10 people who try this
will find that the plane won't fly level for 15 minutes without pilot
input, and of the few that do, the engine coming back to idle will
change the yaw enough that more than half the rest will enter a
spiral.

Michael