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Slip to landing on PPG practical test



 
 
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  #41  
Old November 3rd 04, 06:07 AM
Mark Grubb
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I must take issue with that Mark. I am a much less experienced pilot than you, but let's look at this from my perspective. As safety officer at my club I would exercise my prerogative of referring anyone who wanted to perform slips into the flare for any reason to the CFI for review of their permission to fly.

Hopefully, your CFI is competent and experienced enough to actually
decide based on real evidence that this is "dangerous". Or, if he
does not have adequate experience in this mode, go to altoitude and
try it? As a CFI,this is what I do when faced with the unknown.

I slip Pawnees through the flair many times per day when towing -
probably 5000+ landings worth. All one has to do is maintain adequate
energy - kind of like most other landings.

A few comments -
1] I know it can be done, and even reasonably safely.


2] I know it is dangerous to do this in anything with long wings...


Not true. Remember all those 1000's of documented landings in
AS-W12's in horrendous conditions? The '12 is 19m. Is that not long
winged? The AS-W17 is 20m. i have slipped these to landings several
times. Based on actual experience, it is difficult to keep the wingtip
below the bottom of the main gear in a Steady-State slip in any of
these ships.

Do not believe? Go fly a steady-state slip at altitude and measure
the bank angle. Go get a pile of real DATA! Go fly and judge for
yourself.

While all of this sounds extreme and dangerous, it is most definitely
not. The techniques were developed by some of the most experienced,
analytical and conservative pilots in the sport. As I said
previously, I have actually tried all of these techniques, first at
altitude and then in many gliders to full stop landings. While it is
considerably more difficult than conventional landings, it is not
superhuman nor dangerous. If this were the case, most of the 12's
would be scrap of balsa and glass and the pilots dead. Neither is the
case! There is a very large amount of empirical evidence from many
different locations in the wildest weather to support this theory!


Stalling in severe slips results in the nosefalling through and out of
the slip to a wings level recovery with very little effort or altitude
loss. Dragging a wingtip in glass during a Steady-State slip is
difficult as the wingtip is never lower than the main wheel. These
gliders are severely rudder-limited. If the ship touches down in a
slip, it bounces up and straightens itself out (at least for the '12.
Never had it happen in any other ship!)

While I am high-time in power and glider and was flying more than
full-time (7 days /week for many months, for many years) when I was
training for the '12, I do not consider myself a super pilot and
several of my less experienced friends were able to consistently land
their 15m / std glass ships spoilerless in less than 2000 ft. It
became something to practice so that our skill set and experience was
incresead - a Good Thing.

6] Experience is less indicative of safety than is attitude, ask someone like JJ where most of the repair jobs come from.


Heck, ask JJ about the ships HE busted! From that data set, one would
argue that racing and flying X-C was extremely dangerous and thus
should be avoided. He has not quit flying X-C or racing. Neither
have I.

Our club's founder - Dieter Henschell learned to fly in the 1940s.

His favorite demonstration to pupils who insisted on too high
approaches was to make a normal approach in the Blanik and then
proceed up the 2km runway with the brakes closed from around 10m
height and 100km/h. All the way reciting in his gentle German accent,
look the speed is X and I am still flying.. Look the speed is now x-5
and I am still flying...Most students got the point in one.

What is the point? That a Blanik glides along way with the brakes
closed? What has this got to do with high approaches? You already
established that all modern gliders glide very flat in ground effect.

It is possible to turn downwind abeam the touchdown point at 10,000 ft
AGL (3000 m AGL) in Blaniks, G103, and K21 (among many others) and fly
a normal size pattern by applying full brakes and mantaining
maneuvering speed or higher (a 3:1 glide +/-). What would then be too
high a pattern? 15,000 ft (5000 m) AGL?

I would propose that wafting along at very low speed very close to the
ground exposes you to significant hazard of getting puonded into the
ground by turbulence or falling to the ground when the gust dies or a
thermal breaks loose in front of you. Should your mentor have avodied
this exercise due to these hazards? I have personally seen perhaps
5-10 gliders that were damaged this way.

What am I achieving, other than to demonstrate my poor judgment by practicing slips into the flare?


That you have additional control and mastery of your aircraft? That
you more fully understand its limitations and therefore its
possibilities? that you have more experience that may one day save
you from the unexpected?

And again, Empirical evidence DOES NOT support your hypothesis that
slipping through the flair or landing via slips is dangerous. I have
watched tow pilots and Ag pilots slip through the flair routinely for
several decades. I have done it myself for several decades and
thousands of landings accident-free.

This real-world DATA.

However, You should certainly Believe and Fly as fits your needs,
skills, mind set, and risk tolerance.

Come to California and we can go fly!

Best, Mark
  #42  
Old November 3rd 04, 01:23 PM
Bruce Greeff
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Clearly I have a lot to learn here, but I still think such exercises should not
be routine. Too high risk for no tangible benefit.

Will go and experiment though (just not close to the ground).

  #43  
Old November 3rd 04, 03:28 PM
J.A.M.
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You don't find tangible benefits for slipping in final? In my case it helped
save an outlanding in a mountain area, with only a short field available to
me. It was uphill, with an elevated road just before. Had to get a high
descent rate to clear the obstacle and still have field enough to stop.
Without slipping the glider I think I wouldn't been able to stop in time and
I'd have damaged the plane.
Better to learn how to slip in a controlled environment rather than in a
high stress situation (as an outlanding to a short field).
It can come in handy if you turned to final too high, true that you can
avoid the situation, but then again I prefer having the tools ready just in
case I need them, then work for not needing them. Just my opinion here of
course.

Good landings,
Jose M. Alvarez.

"Bruce Greeff" escribió en el mensaje
...
Clearly I have a lot to learn here, but I still think such exercises

should not
be routine. Too high risk for no tangible benefit.

Will go and experiment though (just not close to the ground).



  #44  
Old November 3rd 04, 05:27 PM
Bruce Greeff
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J.A.M. wrote:
You don't find tangible benefits for slipping in final? In my case it helped
save an outlanding in a mountain area, with only a short field available to
me. It was uphill, with an elevated road just before. Had to get a high
descent rate to clear the obstacle and still have field enough to stop.
Without slipping the glider I think I wouldn't been able to stop in time and
I'd have damaged the plane.

Slipping on final - 100% agreement it is something to learn to do , especially
if you fly XC and may need to land out over obstacles as you have described.

What I am disagreeing with is practising landing with no drag controls other
than side slip, and holding the slip into the flare. Knowing that you can do it
in an emergency is one thing, doing it as a matter of course is not.
Better to learn how to slip in a controlled environment rather than in a
high stress situation (as an outlanding to a short field).

Agree - just like I think everyone should be competent at spins. Same principle,
practice away from the hard stuff...

It can come in handy if you turned to final too high, true that you can
avoid the situation, but then again I prefer having the tools ready just in
case I need them, then work for not needing them. Just my opinion here of
course.

Mine is only an opinion too, and maybe an "old woman" one at that.
Good landings,
Jose M. Alvarez.

"Bruce Greeff" escribió en el mensaje
...

Clearly I have a lot to learn here, but I still think such exercises


should not

be routine. Too high risk for no tangible benefit.

Will go and experiment though (just not close to the ground).




  #46  
Old November 3rd 04, 07:20 PM
Andy Durbin
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Eric Greenwell wrote in message ...

Has anyone else had spoilers freeze shut without flying in clouds, were
it seems like you should be expecting it to happen?


I had the ailerons and I think the elevator freeze up on a wave flight
in a Std Jantar many years ago. I broke the controls loose with
increased stick forces and made sure I kept the stick moving a bit
after that. Didn't enter cloud so assume moisture in the control
circuits or control hinges froze.

Andy
  #47  
Old November 3rd 04, 11:54 PM
Chris OCallaghan
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Always good to hear pilots' real world experiences.

I'll add that most flight manuals warn of spoiler freeze up for both
the reasons cited (mating surfaces and control stiffness) and
recommend ways to mitigate them.

I think this was descibed at length in a thread on the same subject a
year or two ago.

While it's nice to be able to effectively slip a glider (an
increasingly uncommon skill), it's even better if all your controls
work throughout the entire flight. Don't let others lull you into
preflight complacency. Their skills may be greater. I practice no
spoiler approaches regularly (at least a half dozen times a season).
In high performance gliders, I'm only successful about half the time
(that is, I need to pop the spoilers to keep from overshooting). It's
a great excercise, but occasionally humbling.
  #48  
Old November 4th 04, 03:27 AM
Mark James Boyd
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I haven't tried this manuever myself. I'd be a bit hesitant
due to the airspeed errors in some aircraft in a sideslip, and
the need for excellent airspeed control for ensured success.
Additionally, I suspect the correct airspeed varies enough
with weight that this is another factor to consider, and
is a little beyond the scope of the PPG.

Of course I will try it for fun, but for students I wouldn't
like to have them practicing this solo (when the weight is very different).
I remember trying this in the Katana DA-C1 by not using
flaps, and that the airspeed control needed meant one was at
well less than 1.3 x Vs1...

In article ,
CV wrote:

Andreas Maurer wrote:
I bet that this FAA examiner has never done that either in a modern
glider with an L/D over 30 - otherwise he's know that it's going to
take a runway of *at least* 6.000 ft and a sideslip to *very* low
altitude to be able to land without using the airbrakes.


Considering the L/D is increased by ground effect, even doubled
according to some, you have a point.

But even with an L/D of 1:80, if you sideslip to 1 m off the
ground you'll only float 80 m, about 260ft, from there, and
quite a bit less with a headwind.

Agreed that the precision needed to slip it down that low
is probably too much to ask of someone just about to get their
licence, but it does not sound too crazy as an exercise at
a more experienced level. In case you get it wrong you should
of course be ready to abort and pull the brakes well before
there is any danger of going off the far end.

Cheers CV



--

------------+
Mark J. Boyd
  #49  
Old November 4th 04, 03:10 PM
Tony Verhulst
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Mark James Boyd wrote:
I haven't tried this manuever myself. I'd be a bit hesitant
due to the airspeed errors in some aircraft in a sideslip, and
the need for excellent airspeed control for ensured success.


Yeah, I routinely see L23 airspeed errors of -20 kts or more in a full
slip. I emphasize noting the pitch attitude before entering the slip and
maintaining it in the slip. Ignore the ASI.

Tony V.

  #50  
Old November 4th 04, 03:46 PM
Bruce Greeff
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Tony Verhulst wrote:
Mark James Boyd wrote:

I haven't tried this manuever myself. I'd be a bit hesitant
due to the airspeed errors in some aircraft in a sideslip, and
the need for excellent airspeed control for ensured success.



Yeah, I routinely see L23 airspeed errors of -20 kts or more in a full
slip. I emphasize noting the pitch attitude before entering the slip and
maintaining it in the slip. Ignore the ASI.

Tony V.

Any pot pitot is going to be inaccurate, a 50 deg slip as discussed earlier
means you can only rely on attitude for airspeed.
On my Cirrus anything more than a very modest yaw results in wild airspeed
fluctuations - presumably due to buffeting of the static and the disturbed
airflow over the pot.

One reason why people are suggesting you need extremely good airspeed control
and a little extra speed in case of misjudgement.
 




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