Recommended training for newbie Discus owner.
LAS
2-33, G-103 and ASK-21. I'm about to take delivery of a Discus and would
like to get some opinions about what sort of training I should undertake
before I strap that thing on and go. Comments anyone?
Armand A. Medeiros
Have your instructor watch your takeoff and landings...do 25 flights in a
lower performance before jumping into the hot potatoe.
Armand
"LAS" <tvla...@attbi.com> wrote in message
news:iGW89.199360$sA3.2...@rwcrnsc52.ops.asp.att.net...
Marc Ramsey
Well, the best thing to do would be to get a few flights with a
CFIG in a Duo Discus (or DG 505, etc.). Where are you located?
Marc
Caracole
a nosedragger. You now want to fly a taildragger.
Everything you have flown to date is VERY spin resistant flown dual,
unless you found an extremely thorough (unusual) school that has
tail weights for their K-21 and made you fly at an aft in range CG.
All the private owner/racer/pseudo racer guys will tell you to fill
that tail tank in the Discus and fly it at max aft CG. Whee -- less
total induced drag, better performance. Not my choice for 1st flights.
That sweet, honest, predictable little Schempp will spin like
a reliable top at aft allowable range. She will also recover very
predictably, if the pilot has appropriate training, technique and altitude.
As a slipper, she will accelerate unlike anything glider you have flown
after unstalling. No over-G'ing here please.
MANY used gliders I have met have been found to have very
'interesting' maintenance histories, that do not nearly accurately
reflect the current equipment, the repair history and most pertinently,
the current weight & balance. Without valid W&B data, your planning
and training may be moot.
Can you hold airspeed in the pattern to within plus or minus three knots?
Can you make a touch down in the K-21 or G-103 on your selection
of touchdown attitude (main wheel roll on, 2-point roll on or tail first
roll-on)?
At your selected touchdown placement within about 40 feet?
Get that handled, get spin and spiral recovery training (even in a nice
little Citabria or Aerobat, if your K-21 has no tail weights), and get
REAL weight & balance by rolling your lovely onto a scale somewhere.
Pick a nice, low traffic, mild weather day, and commit yourself to a
few high tows, some soaring time, some slowflight investigation, and
several unrushed low-energy tailwheel low or 2-point touchdowns.
Get your landing accuracy to reliably within a 500 foot total stop distance
before you risk that elegant gal on any cross-country, chasin' the
buddies, lust. That way she will serve you nicely for another ten years
in her life.
Cindy B
Caracole Soaring
www.caracolesoaring.com
"LAS" <tvla...@attbi.com> wrote in message
news:iGW89.199360$sA3.2...@rwcrnsc52.ops.asp.att.net...
Robert John
;-)
Rob
At 05:30 22 August 2002, Armand A. Medeiros wrote:
>Fly a lower performance single seater ........before
Robert John
but you ARE running for office aren't you?
:-) Good luck Rob
rjciii
> "...what sort of training I should undertake
> before I strap that thing on and go. Comments anyone?
If you really are a T.V. lawyer then I suggest take a pattern tow,
point the glider straight at the ground, and don't flair until you can
count individual blades of grass!
Please avoid the urge to sue the manufacturer, instructor, airfield
operator, etc., because you screw up and have a hard landing. Soaring
is cost prohibitive enough already.
Wish I could say "Just kidding", but...
Armand A. Medeiros
have rubbed off on me...
LOL!
Atmand
8-)
"Robert John" <REMOVE_TO_REP...@gliderpilot.net> wrote in message
news:ak2902$1eubcd$1...@ID-49798.news.dfncis.de...
William Wallace
news:vl599.3175$6m1.20...@newssvr14.news.prodigy.com...
> I KNEW someone would catch that...POTATO and POTATOES. Sheesh...Quail must
> have rubbed off on me...
More than you know, apparently. His name is Quayle.
Armand A. Medeiros
spelling checker!
Besides...I can misspell his name any way I want! There! LOL! I didn't vote
for him!
8-)
Armand
"William Wallace" <fre...@nospammers.com> wrote in message
news:ak2qcq$mci$1...@slb2.atl.mindspring.net...
Andreas Maurer
If you can land the 21 or the 103 with the tail wheel first you are
easily able to handle the Discus.
Bye
Andreas
Caracole
Yeah, but I promise to be more opinionated than any
registered party member. Not that that would entitle me
to be rude or defamatory.
WYSIWYG would seem an appropriate placard in this media....
Maybe I will order French fries and hot wings for lunch. ;-)
Since I don't want to be a Vice-President.
Thanks for the well wishes,
Cindy
"Robert John" <REMOVE_TO_REP...@gliderpilot.net> wrote in message
news:ak294g$1fakf0$1...@ID-49798.news.dfncis.de...
Ed Byars
in the club Discus shortly after solo because they consider it their most
docile single seater.
I agree it's docile but strongly urge you pay close attention to Cindy's
excellent assessment, especially the part about W&B. Don't take old book
figures. Weigh your glider and keep it in the mid CG range for the first 100
or so hours.
Good luck. You will love the ship. BTW, I speak from 1000+ hrs Discus time
(owned 4, 3Bs and an A) and several thousand other 15m time.
Ed Byars
"LAS" <tvla...@attbi.com> wrote in message
news:iGW89.199360$sA3.2...@rwcrnsc52.ops.asp.att.net...
mic...@lpthe.jussieu.fr
If i remember well, i have read in this newsgroup that an experimented
pilot killed himself in a Discus not so long ago by spinning close to the
ground. Also these performance gliders accelerate very fast, which
may cause problem for landing. The gliders above like the ASK-21 don't
prepare at all for such situations! I think transitioning through a more
friendly glider like the LS4 would be a sane idea. Also flying double
in performance gliders like the Janus which also have good acceleration
and are able to show convincing spin (i remember having been exposed
to spin in a Janus by a very nice instructor who unfortunately killed
himself in the Alps with his brand new Schleicher. Well it takes
speed very very fast and you are quite vertical).
--
Michel Talon
Deputy Dog
forward of the aft limit). I fly mine at 85% and it is VERY resistant to
spinning. Will just go into a spiral. Watch that thought, because the
speed will pick up very quickly as others have stated.
While far from an expert (about 140 hrs in Discus), I can say that it is a
very easy ship to transition to if you have some other single seat time. I
have flown several other singles including DG 300 & Grob 102, Astir and the
Discus is the best and easiest to fly especially if you have nose hook.
With 70% CG or so for starters, trim it slightly nose down (1/4 way between
neutral and full down) and just keep wings level (no elevator input) til the
tail comes up and then it flies as any other ship. Elevator may feel
slightly more sensitive than you are use to.
BE SURE and check the actual flying CG. Schempp-Hirth makes it pretty easy
to determine that. Cut a little block of wood to tape to a level to make a
100:4.4 for B model if I remember correctly (slightly different for the A
model), jack up the tail with the level and wedge on the tail boom (trailer
dolly jack and a few boards works good) and a scale under the tailwheel and
carefully climb in and have someone read the scale(and level the wing) once
you are in flying position (legs on pedals etc. and canopy closed - canopy
makes quite a difference in weight reading when open) The manual gives a
MAXIMUM weight on the tailwheel for different cockpit loads(they are in the
neighboorhood of 30to 40 pounds) so dont' need a big scale) Get the weight
4 to 6 pounds lighter and you will be close to the 70% to 80% range. We
found a 9 pound brass tailwheel hub in my buddies after he bought it, and he
would have been aft of the aft limit with it in there, so it pays to check!!
Only real caveat I have is that the spoilers are EXTREMELY EFFECTIVE and
deploy easily once you get past the "overcenter" lock and at moderately high
speeds (above 70 to 75 knots) if you let them pop open fully, the
deceleration is abrupt and you might induce some wild PIO's as you slide
forward in the seat and take the stick with you. I did it accidently at
about 110 kts when I was guarding the spoiler handle and hit a strong
thermal and probably knocked them open with my fingers (keep those fingers
off the handle). Even with 5 point harness I did the most VIOLENT maneuver
I have experienced in 32 years of flying. 3 head knocks on the canopy. (the
canopy is tuff!) Lucky to be around to laugh about it now. Not the ships
fault at all. I was the dummy. Fortunately I can pass on the info so
others won't experience it. Consider this if you ever have the inclination
to do a truely "low pass". I was at 500 ft and that is all that save me.
Bottom line: Great beginners and advanced soaring machine. It has the
performance, but none of the bad habits. Enjoy it!
One question: Is it the one from Switzerland? I did the test flight on
that one last week. If it is, let me know back. There was one bug I
discovered on the test flight that ought to be fixed. Simple fix, but needs
to be done.
-Cheers
Deputy Dog (K9) Discus B
"LAS" <tvla...@attbi.com> wrote in message
news:iGW89.199360$sA3.2...@rwcrnsc52.ops.asp.att.net...
Jim H
>like to get some opinions about what sort of training I should undertake
>before I strap that thing on and go. Comments anyone?
Get some time in a Pilatus B-4.
Jim H.
CFIG
N483SZ
gapagod...@aol.com
Jim H
>have rubbed off on me...
Don't seat it, Clinton rubbed off on Monica....and rubbed and rubbed and
rubbed...
Paul Remde
I'm not sure that I agree with the Pilatus suggestion. The Pilatus B-4 was
my first single-seater and the mount I used for many of my first badge
flights. It was a lot of fun, but due to it's aerobatic capabilities, I
found it a bit over sensitive. Many single-seat gliders are pitch
sensitive, but the Pilatus is more so than most. The elevator is HUGE. I
think I measured it at 14' once. I saw many club members do major PIO's on
take-off and/or landing. That is not to say that I didn't enjoy the
Pilatus. I loved it. Now that I have some aerobatic experience I'd love
some time in one!
I have not flown a Discus, but I have heard that they are very easy to fly.
I would recommend a flight or two in a Junior. Our club has one and I'd say
it is the smoothest, easiest-to-fly single seater I've flown. It's very
nice. It has thick wings so it is not overly slippery in the pattern.
Perhaps I should explain that slippery can be bad for a low time pilot
because a minor change in pitch can lead to major changes in airspeed. A
few seconds of inattention can lead to overspeeding and the risk of
over-running the end of the runway. However, the Discus has very effective
airbrakes so I wouldn't worry about that much.
Paul Remde
"Jim H" <gap...@aol.comSTOPSPAM> wrote in message
news:20020822205421...@mb-fn.aol.com...
Robertmudd1u
<d...@atlantic.net> writes:
>Only real caveat I have is that the spoilers are EXTREMELY EFFECTIVE
The Discus is equiped with air brakes not spoilers. In fact the type is
generally refered to as Schempp-Hirth type air brakes.
Robert Mudd
Ruud Holswilder
>
>If you can land the 21 or the 103 with the tail wheel first you are
>easily able to handle the Discus.
>
I fully agree to that.
My son flew that "kiddie glider" with comfort and expertise at age 15.
Jim H
>take-off and/or landing. That is not to say that I didn't enjoy the
>Pilatus. I loved it. Now that I have some aerobatic experience I'd love
>some time in one!
Paul,
I think your answer reinforces my rationale for the Pilatus. If someone can
fly a Pilatus, they can "dumb down" to a Discus.
rjciii
> "The Discus is equiped with air brakes not spoilers."
O.K., I'll bite--
What's the difference between air brakes and spoilers?
While we're at it, how about dive brakes vs. air brakes?
Roger Kelly
news:5pucmu0g09m2guq5d...@4ax.com:
> rjco...@msn.com (rjciii) wrote:
>
>>What's the difference between air brakes and spoilers?
>
> In the view of some people "spoilers" are smaller devices
> whose principle function is to destroy ("spoil") the lift
> generated by a wing while "air brakes" are larger devices
> that stick up into the airflow and generate large amounts of
> drag.
>
> Personally, I think it's a matter of degree. I don't know
> anything called an "air brake" that doesn't also act to
> spoil the lift and I don't know anything called a "spoiler"
> that doesn't also generate substantial drag.
>
>>While we're at it, how about dive brakes vs. air brakes?
>
> The term "dive brakes" sometimes implies even more drag than
> is produced by air brakes. It's more commonly used with an
> aircraft that can meet a specified limit such as: won't
> exceed Vne in a vertical or 45 degree "dive" with the dive
> brakes deployed. Again, it's a matter of degree and not all
> pilots or CFI's make any distinction between these three
> terms
>
> (IMHO it's a bit anal to correct someone for using the
> "wrong" term)
>
> Todd Pattist - "WH" Ventus C
> (Remove DONTSPAMME from address to email reply.)
>
I asked a CFIG the same question and the reply was "pull the handle... if
the first response is to lose air speed then they're air brakes. If the
aircraft maintains most of it's speed but starts losing altitude then
they're spoilers. Not much of a distinction IMHO as a beginner.
Roger Kelly
Robertmudd1u
<tpat...@DONTSPAMME.snet.net> writes:
>(IMHO it's a bit anal to correct someone for using the
>"wrong" term)
IMOH it is wrong to not use the correct term. Air brake is the term that both
the manufactuer and the certifing authority use.
As a CFIG I want my students to know and understand the diffrence, and to call
parts of the glider by their correct name.
If we rename everything to siute our personel whims where will it stop? What
shall we call the rudder this week?
Robert Mudd
Robertmudd1u
<rke...@nospampyramidlife.com> writes:
>I asked a CFIG the same question and the reply was "pull the handle... if
>the first response is to lose air speed then they're air brakes. If the
>aircraft maintains most of it's speed but starts losing altitude then
>they're spoilers.
This CFIG needs to do a bit more reading. A good place to start would be Derek
Piggott's book "Understanding Gliding" (1996). He clearly distinguishes between
the two devices throughout the book.
The spoilers on a SGS 1-26B do not do what the air brakes on a Discus do, not
even close.
U.S. trained pilots are the only ones that seem to have a problem with this
terminology. If you read Sailplane and Gliding you quickly see that the English
understand the difference and use the terms correctly. I have flown in England
and never heard the air brakes referred to as spoilers. How is it that the
British seem to get it right?
Robert Mudd
Andreas Maurer
>Paul,
>
>I think your answer reinforces my rationale for the Pilatus. If someone can
>fly a Pilatus, they can "dumb down" to a Discus.
Hmm...
So the Pilatus is more demanding to fly than the Discus?
Why fly the Pilatus at all then before flying the Discus? To damage
the cheaper plane in case something goes wrong?
Wy not simply fly the easier glider - the Discus- first?
Bye
Andreas
Ruud Holswilder
>I am a newly rated pvt glider pilot (atp rated for power), been training in
>2-33, G-103 and ASK-21. I'm about to take delivery of a Discus and would
>like to get some opinions about what sort of training I should undertake
>before I strap that thing on and go. Comments anyone?
>
I think this has become a very funny thread.
I have seen posting that you should fly type A or type B gliders first
before upgrading to the mighty Discus...
I have read arguments over dive brakes, air brakes and spoilers.
Even a funny vice president was brought into view.
Didn't they say "If anything happens to Bush, shoot Quale!"
I have flown lots of different types of high performance gliders.
Any time someone asked me how it was to fly a certain type of glider,
I always said that it behaved like any other type of glider.
If you're a experienced pilot, go fly your Discus and enjoy it.
Success!
LAS
"Robertmudd1u" <robert...@aol.comnojunk> wrote in message
news:20020824001929...@mb-mr.aol.com...
Bob Kuykendall
> The Discus is equiped with air brakes not spoilers. In fact the type is
> generally refered to as Schempp-Hirth type air brakes.
My favorite (and only) sailplane design text, Dr. Fred Thomas'
_Fundamentals of Sailplane Design_ seems to decline to recognise any
difference between spoilers and air brakes. In fact, I can find no
mention at all of air brakes in the index or elsewhere. The index
entry for spoilers says "see also dive brakes." The section on dive
brakes discusses several schemes of extending protrusions into the
airstream to cause increased descent rate and decreased glide ratio.
The diagram in the section on dive brakes shows two arrangements, one
called "Conventional Schempp-Hirth dive brakes (e.g. Standard
Cirrus)," and another called "Combined flap-brake system (e.g.
Mini-Nimbus, early Ventus)."
Mike Lindsay
writes
>Oh yeah. The same people who drive on the "wrong" side of the road.
>
>
Americans followed the French, who changed over after their revolution.
As for terminology, why do you people insist on calling the tailplane
the stabilizer?
Do any of you know what the Flettners are in France?
Potatoes, potatoes, tomatoes, tomatoes.
>"Robertmudd1u" <robert...@aol.comnojunk> wrote in message
>news:20020824001929...@mb-mr.aol.com...
>How is it that the
>> British seem to get it right?
>> Robert Mudd
>
>
--
Mike Lindsay
Mike Lindsay
Kuykendall <b...@hpaircraft.com> writes
Didn't Casey Jones loose his airbrakes? You should see what a jump he
made!
Several high speed jet aircraft are fitted with airbrakes, presumably to
limit speed in a dive. The JU87 Stuka had DFS brakes very similar in
design to what later went onto sailplanes.
--
Mike Lindsay
Robertmudd1u
b...@hpaircraft.com (Bob Kuykendall) writes:
>My favorite (and only) sailplane design text, Dr. Fred Thomas'
>_Fundamentals of Sailplane Design_ seems to decline to recognise any
>difference between spoilers and air brakes.
The Fred Thomas book "Fundamentals Of Sailplane Design", pg 128 admits that
there is some family resemblance but does say that the "simple hinged-panel
type that swings up and forward" is a spoiler.
Gliders are not designed to Herr Thomas' book they are desined to JAR 22. Find
a mention of spoilers in the JARs.
If the terms air brake and spoiler are interchangeable then what are we to make
of the Peterson, J-4 Javelin glider that uses spoilers exclusively for roll
control or the turbine powered airplane MU-2 that also uses them for roll
control? Are these controls to be called air brakes?
As to being a bit anal retentive, well I thought that was one of the
requirements to be on this news group.
Robert Mudd
Robertmudd1u
>writes
>>Oh yeah. The same people who drive on the "wrong" side of the road.
>>
Robert Mudd
Ian Strachan
<mi...@sailplane.demon.co.uk> writes
snip
>why do you people insist on calling the tailplane
>the stabilizer?
The term "stabiliser" well describes its function in terms of
automatically creating a restoring force after a pitch disturbance.
Words such as "tailplane" and, for the normal axis, the "fin", do not
convey their function.
The term "horizontal stabiliser" does just that.
The term "vertical stabiliser" does its thing also using an identical
principle.
That deals with natural stability in the longitudinal and normal axes,
but what stabilises a conventional aircraft in the roll axis? (answers
in a plain envelope, please).
Anyway, in terms of terminology, I support our friends on the west side
of the pond.
When I brief pupils I make the point that the US terminology "horizontal
stabiliser" and "vertical stabiliser" describe the pitch and yaw
stability functions well.
Look at any conventional aircraft from the side (glider, C-130, 747,
A380) and you can see a rear horizontal stabilising aerodynamic surface.
This works well even where (nowadays) it is aided a bit by computery.
This is he so-called "fly-by-wire which Boeing opposed in public until
they (naturally) needed it for their own designs. Airbus and the
military were first in the field here, hence Boeing's Neanderthal
attitude in the first place.
Anyway, to get back to generalities, the fuselage is a useful structure
for making sure that the two stabilising surfaces at the back end have a
reasonable moment arm with respect to the C of G and C of P.
Never mind about other functions that the fuselage is used for such as
carrying you and me across the world. Its most important function is to
suspend the two stability surfaces at the back, and make the aircraft
simple, safe, and (relatively) cheap.
Basic physics have to be designed in before economics take over.
As for the viability of the Boeing "Sonic Cruiser", I doubt it. It
seems to defy what I call basic physics (aerodynamics, anyway). I would
bet that it will not progress to economic airline service on Boeing
money alone, if anybody's (NASA, DoD, help). After all, Mach 0.98 is a
very difficult area to design for cruise. Basic physics, but perhaps
they do not apply at Seattle or St Louis ....
Hey, how did this get into a discussion on spoilers ....
--
Ian Strachan
mic...@lpthe.jussieu.fr
> On Thu, 22 Aug 2002 00:57:50 GMT, "LAS" <tvla...@attbi.com> wrote:
>>I am a newly rated pvt glider pilot (atp rated for power), been training in
>>2-33, G-103 and ASK-21. I'm about to take delivery of a Discus and would
>>like to get some opinions about what sort of training I should undertake
>>before I strap that thing on and go. Comments anyone?
>>
> I have flown lots of different types of high performance gliders.
> Any time someone asked me how it was to fly a certain type of glider,
> I always said that it behaved like any other type of glider.
> If you're a experienced pilot, go fly your Discus and enjoy it.
If you take care to read the above text you will discover that the pilot
does not seem to be experimented. Hence advising to be careful is not
a stupid idea. Of course for someone experimented many gliders are easy
to fly. But do you remember the first time you were allowed to pilot
a high performance glider? I have never seen a club here were you
are going straight from the ASK21 to something like a Discus. You first
do some hours in an ASK23 then in a good but easy glider like the LS4,
after that you are qualified to fly gliders which need fine speed control
and are subject to spinning (at least with certain centering).
> Success!
--
Michel Talon
Andreas Maurer
wrote:
>If the terms air brake and spoiler are interchangeable then what are we to make
>of the Peterson, J-4 Javelin glider that uses spoilers exclusively for roll
>control or the turbine powered airplane MU-2 that also uses them for roll
>control? Are these controls to be called air brakes?
Sure if you can use them to brake...
Extend these controls symmetrically and compare their design to the
design of the airbrakes of a Scheibe Falke.
Or, for example, compare the spoilers on the wing of a fast Mooney to
Schempp Hirt airbrakes.
Identical. Absolutely identical. :)
Bye
Andreas
Robertmudd1u
<mau...@funsystem.de> writes:
>Sure if you can use them to brake...>>
But on the aircraft you mention that can't be done.
>Or, for example, compare the spoilers on the wing of a fast Mooney to
>Schempp Hirt airbrakes.
>Identical. Absolutely identical. :)>>
First of all one must consider that the marketing types at Mooney probably
would not know a true air brake if it fell on them. Are the spoilers on the
Mooney speed limiting? Is that a requirement of certification? I don't know but
highly doubt it. On the other hand, true air brakes, as on the Schempp-Hirth
are speed limiting at some pre determined, regulation controlled, speed.
Sorry they are not identical. You are mixing apples and oranges.
Robert Mudd
Robert Mudd
George Emsden
stabiliser but would have differentiated between spoilers (as on the Falke
for example) and airbrakes as on the ASK 13.
"Ian Strachan" <I...@ukiws.demon.co.uk> wrote in message
news:oclGuRAMB$Z9E...@ukiws.demon.co.uk...
ventus2ct (Ruud Holswilder)
wrote:
>
>If you take care to read the above text you will discover that the pilot
>does not seem to be experimented.
He's a ATP rated power pilot, so he's not a newbe in aviation.
>Hence advising to be careful is not
>a stupid idea. Of course for someone experimented many gliders are easy
>to fly. But do you remember the first time you were allowed to pilot
>a high performance glider? I have never seen a club here were you
>are going straight from the ASK21 to something like a Discus. You first
>do some hours in an ASK23 then in a good but easy glider like the LS4,
>after that you are qualified to fly gliders which need fine speed control
>and are subject to spinning (at least with certain centering).
>
The ASK-23 is a single seat version of the ASK-21 and a Discus
handles just as easy as a LS4.
ventus2ct (Ruud Holswilder)
<I...@ukiws.demon.co.uk> wrote:
>In article <xsaTkBAa...@sailplane.demon.co.uk>, Mike Lindsay
><mi...@sailplane.demon.co.uk> writes
>
>snip
>
>>why do you people insist on calling the tailplane
>>the stabilizer?
>
>The term "stabiliser" well describes its function in terms of
>automatically creating a restoring force after a pitch disturbance.
>
SNIP
He guys, let's start an other dicussion about "landing gear" and
"under carriage"
;-))
Richard Brisbourne
wrote:
>My favorite (and only) sailplane design text, Dr. Fred Thomas'
>_Fundamentals of Sailplane Design_ seems to decline to recognise any
>difference between spoilers and air brakes. In fact, I can find no
>mention at all of air brakes in the index or elsewhere. The index
>entry for spoilers says "see also dive brakes." The section on dive
>brakes discusses several schemes of extending protrusions into the
>airstream to cause increased descent rate and decreased glide ratio.
>
Is this one of those "divided by a common language" issues?
Like roundabouts and rutabaga?
The real name at the left of the e-mail address is richard
Bruce Friesen
advice on what to tell people when they ask the name of those two things
(not three) on the back of my Standard Austria. My fuselage does a
great job of holding them back there - I just don't know what they
are. Any help would be wonderful.
Bruce
JJ Sinclair
between spoilers and dive brakes, who will be the first to tell us all about
it?
JJ Sinclair
Armand A. Medeiros
motor-glider bonnets!
LOL!
"Bruce Friesen" <bandjf...@shaw.ca> wrote in message
news:3D68F0C2...@shaw.ca...
Bruce Friesen
as stabilizers as well as control surfaces?
Cheers
Bruce
Gary Evans
bombers during a run and are spoilers not primarily for spoiling part of
the wings lift?
Bob Kuykendall
>Since we are on the topic of names for things, I would
>sure
>appreciate advice on what to tell people when they
>ask the
>name of those two things (not three) on the back of
>my
>Standard Austria.
On my ships, I call them, alternately, 'the 300-series
parts' and 'stabilizers and ruddervators.' And, sometimes
when I'm tweaking a nose, I'll call the fixed parts
'diagonal stabilizers.'
However, when referring to them informally, I just
call them 'tailfins' and leave it at that.
Thanks, and best regards to all
ADP
Spoilers refer to any device that interferes with lift over the top surface
of the wing. Note that the thingies that pop out of the top of the wing on
a modern glider are about 1/3 of the distance back from the leading edge of
the wing (33% MAC). This is generally the area of maximum lift of an
airfoil and hence a perfect place to put spoilers.
Dive brakes are devices that limit the maximum speed of an aircraft when
needed. The Douglas SBD Dauntless had dive brakes. I know of no glider
with the designation as a "dive bomber".
Speed brakes are another term for spoilers.
Spoilers can be used for roll control as well. by interfering with lift on
one wing at a time.
There was an earlier post on this thread alluding to the fact that the 757
can land with spoilers extended. That is not true. I think the poster
intended to say that the 757 could use speed brakes and flaps at the same
time. This is true. The spoilers on a large Air Transport Aircraft, such
as the 757, have a multi purpose roll. (:-)) They are used for roll
control, they are used as speed brakes to increase rate of descent while not
increasing speed and they are used to kill lift and add drag on the ground
after landing to shorten the landing roll. Of course, anytime that they are
deployed, they add drag. For speed brakes in the air, a 757 uses 3 panels
that deploy from the top of the wing surface aft of 50% MAC. They deploy at
a maximum angle of about 22.5 degrees. For roll control one panel on each
wing deploys in the direction of bank at a maximum angle of about 3 degrees.
On the ground, with the activation of the strut switch, 4 panels on each
wing deploy at a maximum angle of about 45 degrees. Due to the leading edge
devices and fowler flaps which actually change the camber of the wing on a
757, when these devices are deployed, the hinge moment of the spoilers moves
closer to 50% MAC.
As we all know, some gliders have devices that protrude from the top and
bottom surfaces of the wing. The devices that protrude from the top surface
are spoilers, the devices that protrude below are more properly called speed
brakes. Since the same control usually deploys both, there may be some
confusion in nomenclature. I think the term "spoilers" covers these devices
quite nicely.
Incidentally, when speed brakes are deployed on transport aircraft, they
still function as roll control devices and some aircraft have "spoiler ratio
mixer" devices to lessen sensitivity in roll. The 737-200 could get twitchy
with speed brakes being deployed while maneuvering with roll inputs.
Some aircraft have spoilers whose only function is roll control and do not
function as speed brakes.
There, aren't you glad you asked?
Allan
"JJ Sinclair" <jjgl...@aol.com> wrote in message
news:20020825111253...@mb-dh.aol.com...
Bob Kuykendall
>Note that the thingies that pop out of the top of the
>wing on a modern glider are about 1/3 of the distance
>back from the leading edge of the wing (33% MAC).
Innerestin' assertion, but I doubt its verity.
My own survey of contemporary design suggests that
most modern sailplane designers place the whateveryoucall'ems
just aft of the point of maximum thickness. Max thickness
generally occurs at about 41% of the chord (not to
be confused with MAC) for an agressive laminar airfoil
such as the old FX67 or about 38% chord for a more
conservative airfoil such as the FX81.
The reasons I've heard most often for choosing a chordwise
position just aft of max thickness are:
A) It's aft of where you can reasonably expect to retain
laminar flow, so the cap or seam or slot or hinge line
or whatever won't cost as much in drag as if it were
forward of max thickness
B) It's a handy place to put the whateveryoucallem's
because you can anchor their mechanical linkages and
attachments to the rear face of the wing main spar
shear web, which is often located right at the point
of max thickness.
C) It's convenient because it allows for the greatest
height of the whateveryoucallem panels. Away from the
area of max thickness, the panels have to be smaller
in height to fit into the available wing depth.
Also, note that chord does not equal MAC, except in
the case of an unswept constant-chord wing. The concept
of MAC is most useful when relating balance and stability
to a wing planform, and is not very useful when you're
dealing with an isolated wing profile.
Thanks, and best regards to all
Bob K.
http://www.hpaircraft.com/hp-24/
Silent Flyer
ADP <a...@commspeed.net> wrote in message
news:10302969...@news.commspeed.net...
> Well, since you asked:
> SNIP -
*************
> Spoilers refer to any device that interferes with lift over the top
surface
> of the wing. Note that the thingies that pop out of the top of the wing
on
> a modern glider are about 1/3 of the distance back from the leading edge
of
> the wing (33% MAC). This is generally the area of maximum lift of an
> airfoil and hence a perfect place to put spoilers.
>
> Dive brakes are devices that limit the maximum speed of an aircraft when
> needed. The Douglas SBD Dauntless had dive brakes. I know of no glider
> with the designation as a "dive bomber".
>
> Speed brakes are another term for spoilers.
In the post war era all gliders certificated in the UK were required to have
airbrakes that DID limit the airspeed of the glider to the maximum rough air
speed in a vertical dive. Spoilers are not necessarily speed limiting to
this extent. (It was recommended to open the airbrakes if control was lost
whilst cloud flying in order to limit the speed to a safe maximum no matter
what the attitude appeared to be to the pilot)
The arrival of GRP German sailplanes necessitated the adoption of speed
limiting in a 45 degree dive only.
It is correct to say therefore that the devices on all the British
manufactured gliders up to the Libelle and Kestrel from Slingsby were
airbrakes.
Incidentally it was this requirement for speed limiting brakes for
certification in the UK which caused Slingsby to have problems with the HP14
as the flaps could not be easily lowered at high speed to cater for this
speed limiting requirement .
DB
JJ Sinclair
located at or near the trailing edge of the wing and only produce drag. On some
very early standard class ships, these devices would hold the terminal velocity
to less than VNE, hence the sometimes used name of dive brakes. Don't you just
love nit-picking?
BTW, spoilers on a H-201 Libelle are about twice as effective as the air brakes
on an H-301 Libelle.
JJ Sinclair
Ray Lovinggood
JJ,
There must be different versions of the 301. One member
in our club flies a 301 and I've had a chance to look
it over a bit. It has the thingies/spoilers on top
and bottom surfaces of the wings. If I remember right,
they are located immediately behind the spar and not
on the trailing edge. These thingies/spoilers operate
similarly to the thingies/spoilers on the LS-1, LS-4,
LS-8, Standard Cirrus, Ka-6, ASW-19, ASW-24, and HpH-304C
also based at our field. The flaps do go slightly
negative and a bit more positive. I've seen the flaps
moved to the most positive ('down') position, and they
don't go down very far. I would guess 30 degrees??
There is also a drogue chute, which I haven't actually
seen yet, but the hatch on the rudder is there. Whatever...it
is a pretty ship!
Could you mean the H304 and Mosquito and Mini Nimbus
rather than the H301? (While these have the trailing
edge thingies, they also have the middle-of-the-wing
thingies too, I think.)
Ray Lovinggood
Carrboro, North Carolina, USA
news.optonline.net
the sexy planform and the side hinged canopy, I don't think there is very
much difference between the two. They are both representative of their
generation of standard class gliders. Their handicaps are nearly identical.
Sure there may be subtle differences, but I can't see where flying the LS-4
is a necessary prerequisite to flying the Discus.
The comments about checking the CG are wise. Aside from that, as long as you
have mastered the ASK-21, you should be ready to move on to the next
challenge. If you can get time in a Duo or Janus or similar, that would be a
plus. But if not, just make sure you really are the master of the ASK-21,
and can make precision approaches and landings. If not, get more dual and
solo practice until you can. Some spin recognition and recovery training
would be useful as well.
But I don't think there is any need to fly a specific make/model prior to
transitioning to the Discus. Just take it easy and slowly expand your
personal flight envelope, and enjoy your new ship.
"ventus2ct (Ruud Holswilder)" <IHATESPAM...@quicknet.nl> wrote in
message news:7bbhmuk13gmrc8430...@4ax.com...
Bruce Hoult
Ray Lovinggood <REMOVE_TO_...@intrex.net> wrote:
> Could you mean the H304 and Mosquito and Mini Nimbus
> rather than the H301? (While these have the trailing
> edge thingies, they also have the middle-of-the-wing
> thingies too, I think.)
And Club Libelle. The only one of those I've flown is the Libelle. It
doesn't have middle-of-the-wing thingies, but it doesn't need them
because the trailing edge thingies hold it to about 85 knots in a (near)
vertical dive at gross weight. Vne is 108 knots (200 km/h), ISTR.
-- Bruce
ADP
traditional sense. However, unless the wing in question is shaped as a
4'x2''x25' slab, the mean aerodynamic chord represents a value which can be
used as a reference along which to measure.
All of your other points make a great deal of sense to me.
All references I can find concerning modern glider airfoils place the
maximum thickness of the airfoil between 30% and 50% of the airfoil chord
which would not invalidate my point.
The leading edge of the thing-a-ma-bobs on my glider are almost exactly 33%
of the distance from the leading edge of the wing and the trailing edge
measured along the calculated position of the line representing the MAC. It
is precisely that the MAC does not equal the airfoil chord on a tapered wing
that I chose that line along which to measure. From what portion of a
tapered wing would you choose to measure how far back the
what-cha-ma-callits are from the leading edge? It's very convenient that my
dillie-doos bisect the calculated MAC line.
Any how, we agree that fliberty-jibbets are useful on gliders and,
regardless of how they work or what they are called, are useful for a
stabilized approach and landing.
Remember, check your whatisits for stowed position before aero tow or self
launch and let us not add to the glider accident database.
Happy speed diving!
Allan
"Bob Kuykendall" <REMOVE_TO...@hpaircraft.com> wrote in message
news:akb8ta$1h04gs$1...@ID-49798.news.dfncis.de...
Robert Ehrlich
>
> I am a newly rated pvt glider pilot (atp rated for power), been training in
> 2-33, G-103 and ASK-21. I'm about to take delivery of a Discus and would
> like to get some opinions about what sort of training I should undertake
> before I strap that thing on and go. Comments anyone?
After the lots of answers your post triggered, I wonder that nobody pointed
the main difference between the gliders you have flown and the Discus, in
my opinion: the Discus has a retracting gear. Something often heard among glider
pilots is: "There are 2 kinds of pilots, those who already had a gear up
landing and those who are going to do so". I can't say in which category I am,
since I never had a gear up landing but once the gear of a Discus self retracted
after landing when the wheel bumped on a rabbit hole. However I sometimes
forgot to retract it and happily somebody said it to me on the radio. I think
that as an airline pilot you are familiar with retracting gears, but the time
to retract it is specific to gliders, i.e. after realease, before that you
should always be ready for a premature termination of tow, and having the gear
extended is a part of being ready. The main danger in forgetting to retract
the gear is that you may retract it just before landing while you believe you are
extending it.
Graeme Cant
are now the subject.
Are they etymologically related to the 'oliers' fitted to steam locos?
Graeme Cant
mic...@lpthe.jussieu.fr
> I saw two posts recommending flying an LS-4 prior to the Discus. Aside from
> the sexy planform and the side hinged canopy, I don't think there is very
> much difference between the two. They are both representative of their
> is a necessary prerequisite to flying the Discus.
Since i was the one saying that, i simply thought that the LS4 doesn't
accelerate much when the nose goes down (without water of course) hence
it is simple to fly for a beginner. Any other glider which is simple to
fly but not a "flying brick" like the ASK23 would do the same job
perfectly. For example the difference between
the LS4 and the Pegase in this respect is striking, at least for me.
I remember very well having been surprised first time i flew a Pegase,
and other people have said me the same thing. On the other hand the LS4
has always appeared to me as extremely easy, even easier than the ASK23.
As for spinning, i have never experimented unwillingly a single stall,
even more wing drop in the LS4 or the Pegase during many flight hours. It seems
that the Discus is more sensible to proper centering. When i see that a
competition guy kills himself spinning when landing i ask questions.
> The comments about checking the CG are wise. Aside from that, as long as you
> have mastered the ASK-21, you should be ready to move on to the next
> challenge. If you can get time in a Duo or Janus or similar, that would be a
> plus. But if not, just make sure you really are the master of the ASK-21,
> and can make precision approaches and landings. If not, get more dual and
> solo practice until you can. Some spin recognition and recovery training
> would be useful as well.
I have read in this same newsgroup that some glider schools in England
are buying ASK13 just now because they think the ASK21 is too easy and
does not prepare well to flying performance single seaters securely.
Well i have been formed in the ASK13 so i cannot say anything about that,
but indeed i find the ASK21 a little too easy. I have flewn the Janus quite a
lot, and i find it is a much better trainer for transitioning to high
performance single seaters. In particular concerning precise speed control,
spin avoidance, and training for cross country. Finally you are more or
less saying the same thing above.
--
Michel Talon
Larry Goddard
> LAS wrote:
> >
> > I am a newly rated pvt glider pilot (atp rated for power), been training in
> > 2-33, G-103 and ASK-21. I'm about to take delivery of a Discus and would
> > like to get some opinions about what sort of training I should undertake
> > before I strap that thing on and go. Comments anyone?
>
> After the lots of answers your post triggered, I wonder that nobody pointed
> the main difference between the gliders you have flown and the Discus, in
> my opinion: the Discus has a retracting gear. Something often heard among glider
> pilots is: "There are 2 kinds of pilots, those who already had a gear up
> landing and those who are going to do so". I can't say in which category I am,
> since I never had a gear up landing but once the gear of a Discus self retracted
> after landing when the wheel bumped on a rabbit hole.
Aha! The old 'wheel bumped on a rabbit hole' excuse!! Actually that same thing
happened to me on a solid concrete runway.... You should have seen the size of those
rabbits that had tunneled through all that concrete. :-)
Regards,
Larry Goddard
"01" USA
Albert Gold
of the gear doors.
Since one sometimes flies with ships such cg releases and at other times with nose
mounted hooks, I opt to keep the gear down until release for the sake of having a
uniform procedure.
Al
Todd Pattist wrote:
> Robert Ehrlich <Robert....@inria.fr> wrote:
>
> >but the time
> >to retract it is specific to gliders, i.e. after realease, before that you
> >should always be ready for a premature termination of tow, and having the gear
> >extended is a part of being ready.
>
> I retract on tow at about 1000' AGL. Prior to that time,
> I'm concentrating on a possible PTT and I know exactly what
> I'm going to do if the rope breaks. I'm constantly updating
> the plan in light of the wind and my tow position until I
> reach a sufficient height. After I reach that "safe" height,
> if there's a PTT I'll just turn towards the field, and enter
> a normal pattern, but I'll also try to climb out on any lift
> I find. After gear retraction, I may release in good lift.
>
> I find it helpful to have a divider between the two phases
> of the tow and for me, that divider is gear retraction. I
> know some don't like the possibiilty of distraction during
> tow (that's a legitimate concern), but I like the practice I
> get of finding the gear handle and checking its position
> without changing attitude and without looking (or with a
> very brief controlled look to a specific point) as I often
> need to do when checking gear down at base to final or when
> thermalling low before landing out.
>
> Todd Pattist - "WH" Ventus C
> (Remove DONTSPAMME from address to email reply.)
Bob Kuykendall
> I've kept up with it so far but I'm puzzled about the 'spoliers' that
> are now the subject.
>
> Are they etymologically related to the 'oliers' fitted to steam locos?
I think that they are actually double-edged weapons located about
halfway between the cutlass and the foil on the periodic table of
fencing implements.
:)
Bob "Heisenberg Duality scar" K.
http://www.hpaircraft.com
ADP
and the arithmetic convergence of the ier along a line asymptotic to
infinity!
Or at least they were there the last time I saw them!
Allan
"Graeme Cant" <gc...@internode.on.net> wrote in message
news:3D6A458C...@internode.on.net...
Dieter
question, neither did I spend the time reading everything here.
Possibly the the Question should have been:
Divebrakes vs. Spoilers ? Better yet,......Terminal Velocity
Divebrakes.
I am quite sure my Blaniks L13 had those. You could dive streight
down, if you opened them in time, and never exeed redline. The 2-32
has them also I think.
Doing aerobatics in the Blanik, coming out of a roll or similar and
the red line creeps close, open spoilers slowly, and you were OK.
Also, nice feature for high altitude flights, when you want to come
down in a hurry for Ox reasons or other.
I never did go to that Terminal Velocity feature, or had to.
Dieter
Deputy Dog
Wow! Must be lots of bored folks out there for a simple request for
information on the handling of a Discus to turn into such a lengthy post
regarding "airbrakes" and "spoilers". I hope the poor guy who requested
the info found something useful in all this.
As for "airbrakes" vs. "spoilers" I think you are arguing over words instead
of meaningful knowledge. While I agree that Schempp-Hirth calls them
"airbrakes", I will assure you that those devices on my Discus indeed
"spoil" the lift on the wing as well as creating drag. This is in sharp
contrast to the trailing edge devices found on the Mosquito.
If you disagree, then why does the stall speed go up with them deployed??
If they are merely "airbrakes" as you seem to indicate, then the lift
created by the wing would be the same deployed vs. closed, and the stall
speed would not change, but indeed that is not the case. The manual states
that the stall speed goes up and it does in fact.
If you are hung up on using the "proper terminology" then you ought to scold
Schempp-Hirth for using the term "gear" and "undercarriage" when referring
to the same part of the aircraft in the Discus B manual. Shame on them!
I think you are just arguing terms and not practical knowledge. I would
rather a student have practical knowledge.
As you noted in one of your later posts, as a CFIG, you wanted your students
to "call the parts of the glider by their proper name". I would agree with
that, but when all else fails, if one of my students calls them "spoilers"
instead of "airbrakes", but understands that they do spoil lift on the wing
and therefore increase the stall speed, that is just fine with me, because
the stall is what will ruin their day when they are close to the ground and
deploying those "things"
The Brits have bonnets on their cars. We have hoods. They have
"windscreens", we have "windshields". You get a lot of wind thru a
"screen", so I'd rather have a "shield". I put "gas" in the tug, they put
"petrol". Who's right and who's wrong?? Who knows, and who really cares??
Cheers-
Deputy Dog
"Robertmudd1u" <robert...@aol.comnojunk> wrote in message
news:20020822212559...@mb-ct.aol.com...
> In article <Xhc99.30479$CD2.2...@e3500-atl1.usenetserver.com>, "Deputy
Dog"
> <d...@atlantic.net> writes:
>
> >Only real caveat I have is that the spoilers are EXTREMELY EFFECTIVE
>
> The Discus is equiped with air brakes not spoilers. In fact the type is
> generally refered to as Schempp-Hirth type air brakes.
>
> Robert Mudd
Martin Gregorie
>I would recommend a flight or two in a Junior. Our club has one and I'd say
>it is the smoothest, easiest-to-fly single seater I've flown. It's very
>nice. It has thick wings so it is not overly slippery in the pattern.
>Perhaps I should explain that slippery can be bad for a low time pilot
>because a minor change in pitch can lead to major changes in airspeed. A
>few seconds of inattention can lead to overspeeding and the risk of
>over-running the end of the runway. However, the Discus has very effective
>airbrakes so I wouldn't worry about that much.
>
Agreed. My club transitions people to the Junior as first solo and
then from Junior to Discus or Pegase after 30 hours of Junior time.
The transition involves check flights in a Grob G103 so the instructor
can check the student's speed control.
That said, to me a Discus handles rather like a super Junior except
that it thermals more nose up and the controls are lighter. In both
aircraft note that the attitude when stationery on the ground is the
correct hold-off attitude on landing. The Junior will accept a
nose-high round-out; the Discus is much less forgiving.
PS: Learn to fly left handed before tackling the Discus - you'll need
that experience when raising and lowering the wheel.
--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :
Robert Ehrlich
>
> Aha! The old 'wheel bumped on a rabbit hole' excuse!! Actually that same thing
> happened to me on a solid concrete runway.... You should have seen the size of those
> rabbits that had tunneled through all that concrete. :-)
>
In my case this retraction of the wheel after the glider landed on it properly
extended was the first case for me but not for the glider which was known to
have worn parts in the gear linkage making it prone to that. After this incident
and before a proper repair which was done during the next winter, a small block of
wood was made and hold by a short string for inserting in the slot where the gear
lever moves, preventing it to go out from the locked position when the block of
wood is in place. A proof that the gear retracted in the air after the bounce and
not on the ground is that the gear doors were closed when the glider came back
on the grass runway, so the damage was limited to minor scratches, in fact the
protruding CG hook worked as an emergency secondary gear and brake. Lot of
work to clean it but no damage.
Robert Ehrlich
>
> Gear retraction on tow isn't an option when flying a glider whose release is inside
> of the gear doors.
> Since one sometimes flies with ships such cg releases and at other times with nose
> mounted hooks, I opt to keep the gear down until release for the sake of having a
> uniform procedure.
>
in a club environment where you fly various gliders, some having the release
inside the gear doors and some not. Even during a long aero retrieve, I keep
the gear extended, retract it after release and extend it before entering downwind.
Mike Lindsay
Holswilder) <IHATESPAM...@quicknet.nl> writes
>On Sat, 24 Aug 2002 21:45:00 +0100, Ian Strachan
><I...@ukiws.demon.co.uk> wrote:
>
>>In article <xsaTkBAa...@sailplane.demon.co.uk>, Mike Lindsay
>><mi...@sailplane.demon.co.uk> writes
>>
>>snip
>>
>>>why do you people insist on calling the tailplane
>>>the stabilizer?
>>
>>The term "stabiliser" well describes its function in terms of
>>automatically creating a restoring force after a pitch disturbance.
>>
>He guys, let's start an other dicussion about "landing gear" and
>"under carriage"
>
>;-))
>
OK. Did you know the French refer to this as Le Train?
--
Mike Lindsay
Robert Ehrlich
>
> OK. Did you know the French refer to this as Le Train?
>
And sometimes in pilot's jargon : "la godasse", which is a
word used (fam.) for shoe. "Le train" may refer to one or
more wheels, while "la godasse" refer to only one.
Andreas Maurer
<mar...@see.sig.for.address> wrote:
>PS: Learn to fly left handed before tackling the Discus - you'll need
>that experience when raising and lowering the wheel.
.. or use the trim for these five seconds...
Bye
Andreas