Spoilers or Airbrakes - Whats in a name?

[ContestID67]

I spotted the following statement in Wikipedia.

http://en.wikipedia.org/wiki/Spoiler_%28aeronautics%29
http://en.wikipedia.org/wiki/Air_brake_%28aircraft%29

"Spoilers differ from airbrakes in that airbrakes are designed to
increase drag while making little change to lift, while spoilers
greatly reduce lift while making only a moderate increase in drag."

I had always used the terms spoilers and airbrakes interchangeable.
This statement makes it seem like they are not. So what does the
typical sailplane have? Spoilers or airbrakes?

- John "67" DeRosa

[Mike[_8_]]

On May 16, 9:31 am, ContestID67 > wrote:
> I spotted the following statement in Wikipedia.
>
> http://en.wikipedia.org/wiki/Spoiler_%28aeronautics%29http://en.wikipedia.org/wiki/Air_brake_%28aircraft%29
>
> "Spoilers differ from airbrakes in that airbrakes are designed to
> increase drag while making little change to lift, while spoilers
> greatly reduce lift while making only a moderate increase in drag."
>
> I had always used the terms spoilers and airbrakes interchangeable.
> This statement makes it seem like they are not. So what does the
> typical sailplane have? Spoilers or airbrakes?
>
> - John "67" DeRosa

Oh boy!

According the the original Glasser-Dirks owner's manual for a DG100G,
the sailplane has "spoilers".

[[email protected]]

On May 16, 8:56*am, Mike > wrote:
> On May 16, 9:31 am, ContestID67 > wrote:
>
> > I spotted the following statement in Wikipedia.
>
> >http://en.wikipedia.org/wiki/Spoiler_%28aeronautics%29http://en.wikip...
>
> > "Spoilers differ from airbrakes in that airbrakes are designed to
> > increase drag while making little change to lift, while spoilers
> > greatly reduce lift while making only a moderate increase in drag."
>
> > I had always used the terms spoilers and airbrakes interchangeable.
> > This statement makes it seem like they are not. *So what does the
> > typical sailplane have? *Spoilers or airbrakes?
>
> > - John "67" DeRosa
>
> Oh boy!
>
> According the the original Glasser-Dirks owner's manual for a DG100G,
> the sailplane has "spoilers".

Don't forget "Dive Brakes"!

[Bob Kuykendall]

Launch Robert Mudd post on glidepath control nomenclature on my mark:
three... two... one...

Bob K.

[raulb]

On May 16, 8:31*am, ContestID67 > wrote:
I am not an aerodynamicist and therefore I could be wrong (and
probably am), but I have always thought of airbrakes being terminal
devices. That is, they will limit speed, such as in a dive or on
glidepath. My old BG-12 had terminal flaps and with them all the way
out, you could not go more than about 60 kts no matter where the nose
was pointed. It has been 25 years since I flew one, but if I recall
correctly, doesn't the 1-34 also has terminal dive brakes.

By extrapolation therefore, spoilers are speed devices which spoil
lift and slow the aircraft down but do not limit dive speed.
Airbrakes will limit speed, and that is why you have to be so careful
not to open them when you are too fast.

If I am wrong, so what? I am an idiot anyway.

> I spotted the following statement in Wikipedia.
>
> http://en.wikipedia.org/wiki/Spoiler_%28aeronautics%29http://en.wikipedia.org/wiki/Air_brake_%28aircraft%29
>
> "Spoilers differ from airbrakes in that airbrakes are designed to
> increase drag while making little change to lift, while spoilers
> greatly reduce lift while making only a moderate increase in drag."
>
> I had always used the terms spoilers and airbrakes interchangeable.
> This statement makes it seem like they are not. *So what does the
> typical sailplane have? *Spoilers or airbrakes?
>
> - John "67" DeRosa

[Bill Daniels]

"ContestID67" > wrote in message
...
>I spotted the following statement in Wikipedia.
>
> http://en.wikipedia.org/wiki/Spoiler_%28aeronautics%29
> http://en.wikipedia.org/wiki/Air_brake_%28aircraft%29
>
> "Spoilers differ from airbrakes in that airbrakes are designed to
> increase drag while making little change to lift, while spoilers
> greatly reduce lift while making only a moderate increase in drag."
>
> I had always used the terms spoilers and airbrakes interchangeable.
> This statement makes it seem like they are not. So what does the
> typical sailplane have? Spoilers or airbrakes?
>
> - John "67" DeRosa

Both common sense and aerodynamics say that if the G-meter says 1.0 then
lift = weight. Applying 'spoilers' doesn't change that. Spoilers do not
'reduce lift' if the G-meter continues to say 1.0 - they increase drag.
The general formula is lift = weight x G

The steady state effect of spoilers, airbrakes, dive brakes, and even flaps
all do the same thing - they increase drag. I carefully included the term
'steady state' to exclude brief transient effects that may occur as these
devices are deployed.

If they all do the same thing, why the different terms? I think it goes to
the intent of the pilot. If a pilot wishes to limit airspeed in a steep
dive, whatever device the aircraft is equipped with is used as a 'dive
brake'. If the pilot desires to reduce airspeed without raising the nose
and zooming, the term becomes 'airbrakes'. If the intent is to steepen a
glide without increasing airspeed, 'spoilers' is an appropriate term.

The different terms may also have arisen due to pilots making erroneous snap
judgements about the effect of drag control devices based on the transient
effects. Flaps applied suddenly make the aircraft surge upward so they
'increase lift'. Spoilers make the aircraft drop so they 'decrease lift'.
These transients are very brief and have little effect on the aircraft
trajectory. Thinking "increase drag" is more accurate and will result in
better flying skills. All these terms describe that.

Bill Daniels

[Brian[_1_]]

<snip>
>
> The steady state effect of spoilers, airbrakes, dive brakes, and even flaps
> all do the same thing - they increase drag. * I carefully included the term
> 'steady state' to exclude brief transient effects that may occur as these
> devices are deployed.
>
<snip>

You are correct in steady state the all pretty much do the same thing.
The difference in terms comes in the non steady state effects and how
they produce drag.

Take a glider at approach speed about 5 feet off the runway in steady
state (at least for a glider) level flight with all drag devices
retracted..

If you deploy the spoilers and do not change attitude the glider will
drop onto runway, speed will change very little.

if you deploy airbrakes the glider will slow and settle to the runway.

If you deploy flaps the glider will balloon up.


Brian CFIIG/ASEL

[jonathan]

> "Spoilers differ from airbrakes in that airbrakes are designed to increase
> drag while making little change to lift, while spoilers
> greatly reduce lift while making only a moderate increase in drag."
> what does the typical sailplane have? Spoilers or airbrakes?
> - John "67" DeRosa

A spoiler would be a flap on the top of the wing front hinged forward of the
COP (centre-of-pressure)
such that the when it opens at the free end the airflow across the wing is
spoiled (and hence the lifting action decreased) but not
directly blocked (or braked).

A brake would be a paddle that operates at a right angle to the airflow and
directly blocks the airflow - effectively slowing the movement
of the wing relative to the airflow.

Sort of visualise the difference between a wing (spoiler) on a racing car
creating downpressure and throwing a dirty great parachute out the back to
assist braking?

Jim.

[Andy[_1_]]

On May 16, 8:56*am, Mike > wrote:
> According the the original Glasser-Dirks owner's manual for a DG100G,
> the sailplane has "spoilers".

I suspect that the original owner's manual is written in German and
that the word "spoilers" is not mentioned. I don't have my
Schleicher manual here but I think they call them Klappen. Not being
picky for the sake of it, but pointing out that "spoiler" was probably
the word chosen by the translator not necessarily by the manufacturer.

Andy

[noel.wade]

On May 16, 12:59*pm, "jonathan"
<PLEASE.REMOVE.THIS.PREFIX.jonathan.go...@ntlworld. com> wrote:

> Sort of visualise the difference between a wing (spoiler) on a racing car
> creating downpressure and throwing a dirty great parachute out the back to
> assist braking?
>
> Jim.

Oh, boy - where to begin?

First: In the automobile world, the difference between a "spoiler"
and a "wing" is very important. A wing is a device that allows air to
flow over both top and bottom surfaces, and is typically used to
create down-force (just like the horizontal tail on your glider). A
spoiler actually has the leading edge fixed to the auto in such a way
that air flows over the top surface only. It, too, creates down-
force, but it also creates a lot more drag than a wing.

Second: Technically "spoilers" are supposed to be there to change the
airflow over the _wing_. By "spoiling" the airflow such that it
cannot follow the curves of the airfoil, it changes the glide-path and/
or drag of the aircraft. "Airbrakes" are technically a device
_anywhere_ on the aircraft that increases drag.

Now here's where most people fall down: They want to categorize every
device as one or the other type. But the plain truth is that most
devices on sailplanes do BOTH.

Have fun debating spoilers and airbrakes! I don't think this one will
ever be fully settled...

--Noel

[Eric Greenwell]

Bill Daniels wrote:

> Both common sense and aerodynamics say that if the G-meter says 1.0 then
> lift = weight. Applying 'spoilers' doesn't change that. Spoilers do not
> 'reduce lift' if the G-meter continues to say 1.0 - they increase drag.
> The general formula is lift = weight x G

There is a nuance here: opening the spoilers on most gliders does
diminish the lift of the wing section near the spoilers. To compensate,
the outer panels have to carry more of the weight of the glider. You can
clearly see this on an ASW 20 or open class ship, when the wings bend up
noticeably after the spoilers are open. So, in a steady state condition,
the lift is *decreased* over a significant fraction of the wing, but the
overall lift remains the same.

The reverse is true for flaps used for glidepath control: the lift in
the flapped section is increased. I can see this clearly on my ASH 26 E,
because now the outer panels are bent down slightly when landing flaps
are selected. So, in a steady state condition, the lift is *increased*
over a significant fraction of the wing, but the overall lift remains
the same.

Now, I'd say a true divebrake is what some fighters have: a panel(s)
that pop out of the fuselage, so they only add drag, and don't affect
the lift of the wing. Maybe we should consider our retractable landing
gear our "divebrake".

Of course, we glider pilots are a sloppy bunch and lump divebrakes in
with spoilers, and airbrakes. We pretty much stick with calling flaps,
well, flaps.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

[Andy[_1_]]

On May 16, 12:46*pm, Brian > wrote:

> Take a glider at approach speed about 5 feet off the runway in steady
> state (at least for a glider) level flight with all drag devices
> retracted..
>
> If you deploy the spoilers and do not change attitude the glider will
> drop onto runway, speed will change very little.
>
> if you deploy airbrakes the glider will slow and settle to the runway.
>
> If you deploy flaps the glider will balloon up.

Maintaining a constant attitude in the test you describe will require
a pitch control input and that input controls what happens to the
glider as the devices are deployed. To put it another way,
maintaining pitch attitude is an arbitrary choice. You could have
specified constant sink rate, constant glide path, constant airspeed,
etc etc. That close to the ground my intent is to control sink rate
and the controls interact to achieve that.

In my experience deploying my top surface devices with stick free
results in nose down pitch, increased sink rate, and airspeed remains
essentially constant. Who can define the name of the device that
causes that?

Andy

[toad]

On May 16, 4:34 pm, Eric Greenwell > wrote:
> Bill Daniels wrote:
> > Both common sense and aerodynamics say that if the G-meter says 1.0 then
> > lift = weight. Applying 'spoilers' doesn't change that. Spoilers do not
> > 'reduce lift' if the G-meter continues to say 1.0 - they increase drag.
> > The general formula is lift = weight x G
>
> There is a nuance here: opening the spoilers on most gliders does
> diminish the lift of the wing section near the spoilers. To compensate,
> the outer panels have to carry more of the weight of the glider. You can
> clearly see this on an ASW 20 or open class ship, when the wings bend up
> noticeably after the spoilers are open. So, in a steady state condition,
> the lift is *decreased* over a significant fraction of the wing, but the
> overall lift remains the same.
>
> The reverse is true for flaps used for glidepath control: the lift in
> the flapped section is increased. I can see this clearly on my ASH 26 E,
> because now the outer panels are bent down slightly when landing flaps
> are selected. So, in a steady state condition, the lift is *increased*
> over a significant fraction of the wing, but the overall lift remains
> the same.
>
> Now, I'd say a true divebrake is what some fighters have: a panel(s)
> that pop out of the fuselage, so they only add drag, and don't affect
> the lift of the wing. Maybe we should consider our retractable landing
> gear our "divebrake".
>
> Of course, we glider pilots are a sloppy bunch and lump divebrakes in
> with spoilers, and airbrakes. We pretty much stick with calling flaps,
> well, flaps.
>
> --
> Eric Greenwell - Washington State, USA
> * Change "netto" to "net" to email me directly


An aerodynamicist would say that a spoiler changes the lift vs angle-
of-attach curve of a wing section. It will also change the drag curve
of that wing section.

I don't think there are universally accepted definitions of these
terms.

A side note, just about any kind of device on the wing will affect
both lift and drag, but depending on the location and type, will
affect lift and drag in different proportions. This can lead to
confusion of the terms.

Todd Smith
3S

[Brian[_1_]]

<snip>
> Maintaining a constant attitude in the test you describe will require
> a pitch control input and that input controls what happens to the
> glider as the devices are deployed. *To put it another way,
> maintaining pitch attitude is an arbitrary choice. *You could have
> specified constant sink rate, constant glide path, constant airspeed,
> etc etc. *That close to the ground my intent is to control sink rate
> and the controls interact to achieve that.
>
> In my experience deploying my top surface devices with stick free
> results in nose down pitch, increased sink rate, and airspeed remains
> essentially constant. Who can define the name of the device that
> causes that?
>
> Andy

Yes, I specified constant attitude simply because I can obviously stop
the descent by pitching back up. I was just trying to Isolate the
effects of the various drag devices which as you point out is simlar
no matter what the initial steady state is.

One other feature I have noticed on Spoilers is they tend to be ON/OFF
as opposed to Airbrakes that tend to be more proportional. I.E. in my
example if you slowly apply the Spoilers at a certain point the glider
will just drop. Where as the Airbrakes will tend to gradually become
more effective.

Brian

[Mike[_8_]]

On May 16, 10:43 am, Bob Kuykendall > wrote:
> Launch Robert Mudd post on glidepath control nomenclature on my mark:
> three... two... one...
>
> Bob K.

LOL!

I set Robert up once calling the DG's divebrakes spoilers, after
seeing the term in my DG's manual. The response was as expected. I
then had the pleasure to show him the term in the manual. He told me
he would have to have a talk with Herr Dirks about this the next time
he saw him.

[Shawn[_5_]]

noel.wade wrote:
> On May 16, 12:59 pm, "jonathan"
> <PLEASE.REMOVE.THIS.PREFIX.jonathan.go...@ntlworld. com> wrote:
>
>> Sort of visualise the difference between a wing (spoiler) on a racing car
>> creating downpressure and throwing a dirty great parachute out the back to
>> assist braking?
>>
>> Jim.
>
> Oh, boy - where to begin?
>
> First: In the automobile world, the difference between a "spoiler"
> and a "wing" is very important. A wing is a device that allows air to
> flow over both top and bottom surfaces, and is typically used to
> create down-force (just like the horizontal tail on your glider). A
> spoiler actually has the leading edge fixed to the auto in such a way
> that air flows over the top surface only. It, too, creates down-
> force, but it also creates a lot more drag than a wing.
>
> Second: Technically "spoilers" are supposed to be there to change the
> airflow over the _wing_. By "spoiling" the airflow such that it
> cannot follow the curves of the airfoil, it changes the glide-path and/
> or drag of the aircraft. "Airbrakes" are technically a device
> _anywhere_ on the aircraft that increases drag.
>
> Now here's where most people fall down: They want to categorize every
> device as one or the other type. But the plain truth is that most
> devices on sailplanes do BOTH.
>
> Have fun debating spoilers and airbrakes! I don't think this one will
> ever be fully settled...

I think it's fair to say that the debate is of little significance, but
much concern. ;-)


Shawn

[user]

I'd continue to use them interchangeably until we have a glider with
independent controls for spoilers and airbrakes. However, if you like
precision, I'd opt for spoilers. I can't recall having seen a modern glider
that didn't have upper surface spoilers when equipped with lower surface
airbrakes. If during a positive control check the pilot corrects your call
of "spoilers," look under the wing for the extra control surface.

"ContestID67" > wrote in message
...
>I spotted the following statement in Wikipedia.
>
> http://en.wikipedia.org/wiki/Spoiler_%28aeronautics%29
> http://en.wikipedia.org/wiki/Air_brake_%28aircraft%29
>
> "Spoilers differ from airbrakes in that airbrakes are designed to
> increase drag while making little change to lift, while spoilers
> greatly reduce lift while making only a moderate increase in drag."
>
> I had always used the terms spoilers and airbrakes interchangeable.
> This statement makes it seem like they are not. So what does the
> typical sailplane have? Spoilers or airbrakes?
>
> - John "67" DeRosa

[Tony Verhulst]

user wrote:
> I'd continue to use them interchangeably .....
> If during a positive control check the pilot corrects your call
> of "spoilers," look under the wing for the extra control surface.

Yes, I've seen at least 2 books (FAA Glider Flying Handbook and Russell
Holtz's Glider Pilot's Handbook of Aeronautical Knowledge)where the
writer claimed that if the ..um.. "device".. extended top surface only
it was a spoiler and if it extended from both survaces it was an air
brake. Seems dubious to me.

Tony V LS6-b "6N"

[Shawn[_5_]]

user wrote:
> I'd continue to use them interchangeably until we have a glider with
> independent controls for spoilers and airbrakes. However, if you like
> precision, I'd opt for spoilers. I can't recall having seen a modern glider
> that didn't have upper surface spoilers when equipped with lower surface
> airbrakes. If during a positive control check the pilot corrects your call
> of "spoilers," look under the wing for the extra control surface.

FWIW I always thought of my Ventus and Mosquito "Approach Control
Devices" (at least the top part) as air brakes. Doesn't seem like much
lift spoiling going on all the way back there.


Shawn

[[email protected]]

Spoilers American Heritage Dictionary –

A long, narrow hinged plate on the upper surface of an airplane wing
that reduces lift and increases drag when raised.

Brakes American Heritage Dictionary

A device for slowing or stopping motion, as of a vehicle, especially
by contact friction.
Something that slows or stops action.

[Nyal Williams[_2_]]

Way back when ... there were terminal velocity dive brakes on gliders. (I
believe another term was DFS dive brakes, but am not sure about that).
These brakes would hold the glider below VNe in a vertical dive. At some
point, as air foils became thinner, manufacturers agreed that the air
brakes would be designed to hold the glider below VNe at a 45 deg. descent
angle. I believe this was sanctioned by JAR, IGC, or some such.

Spoilers will place no limit on speed and cannot be used in a steep or
High Parasitic Drag Approach, whereas airbrakes can be.

No one has mentioned an important difference between flaps and airbrakes
(whether spoilers, divebrakes, airbrakes, or your term of choice). This
difference is the effect had on closing them after having established a
stabilized descent under their use.

Retracting the airbrakes causes the stall speed to be lowered and the
glide angle to improve. If you are low and slow, retracting improves
EVERYTHING.

If you are low and slow and retract flaps, stall speed goes UP and you
might find yourself in the woods, creek, fence, or whatever is short of
the touchdown point.


At 13:53 17 May 2008, Tony Verhulst wrote:
&gt;user wrote:
&gt;&gt; I'd continue to use them interchangeably .....
&gt; &gt; If during a positive control check the pilot corrects your call
&gt;&gt; of &quot;spoilers,&quot; look under the wing for the extra
control surface.
&gt;
&gt;Yes, I've seen at least 2 books (FAA Glider Flying Handbook and
Russell
&gt;Holtz's Glider Pilot's Handbook of Aeronautical Knowledge)where the

&gt;writer claimed that if the ..um.. &quot;device&quot;.. extended top
surface only
&gt;it was a spoiler and if it extended from both survaces it was an air
&gt;brake. Seems dubious to me.
&gt;
&gt;Tony V LS6-b &quot;6N&quot;
&gt;

[Ralph Jones[_2_]]

On Sat, 17 May 2008 11:01:06 -0700 (PDT),
wrote:

>Spoilers American Heritage Dictionary –
>
>A long, narrow hinged plate on the upper surface of an airplane wing
>that reduces lift and increases drag when raised.
>
>Brakes American Heritage Dictionary
>
>A device for slowing or stopping motion, as of a vehicle, especially
>by contact friction.
>Something that slows or stops action.

Variometer American Heritage Dictionary

A variable inductor used to measure variations in terrestrial
magnetism.

rj

[Nyal Williams[_2_]]

Poorly stated; corrections inserted.

At 23:10 17 May 2008, Nyal Williams wrote:
&gt;Way back when ... there were terminal velocity dive brakes on gliders.
(I
&gt;believe another term was DFS dive brakes, but am not sure about that).

&gt;These brakes would hold the glider below VNe in a vertical dive. At
some
&gt;point, as air foils became thinner, manufacturers agreed that the air
&gt;brakes would be designed to hold the glider below VNe at a 45 deg.
descent
&gt;angle. I believe this was sanctioned by JAR, IGC, or some such.
&gt;
&gt;Spoilers will place no limit on speed and [will not be effective] in a
steep or

&gt;High Parasitic Drag Approach, whereas airbrakes can be.
&gt;
&gt;No one has mentioned an important difference between flaps and
airbrakes
&gt;(whether spoilers, divebrakes, airbrakes, or your term of choice).
This
&gt;difference is the effect had on closing them after having established
a
&gt;stabilized descent under their use.
&gt;
&gt;Retracting the airbrakes causes the stall speed to be lowered and the
&gt;glide angle to improve. If you are low and slow, retracting improves
&gt;EVERYTHING.
&gt;
&gt;If you are low and slow and retract flaps, stall speed goes UP [the
lift DECREASES]
and you
&gt;might find yourself in the woods, creek, fence, or whatever is short
of
&gt;the touchdown point.
&gt;
&gt;
&gt;At 13:53 17 May 2008, Tony Verhulst wrote:
&gt;&gt;user wrote:
&gt;&gt;&gt; I'd continue to use them interchangeably .....
&gt;&gt; &gt; If during a positive control check the pilot corrects your
call
&gt;&gt;&gt; of &quot;spoilers,&quot; look under the wing for the extra
&gt;control surface.
&gt;&gt;
&gt;&gt;Yes, I've seen at least 2 books (FAA Glider Flying Handbook and
&gt;Russell
&gt;&gt;Holtz's Glider Pilot's Handbook of Aeronautical Knowledge)where
the
&gt;
&gt;&gt;writer claimed that if the ..um.. &quot;device&quot;.. extended
top
&gt;surface only
&gt;&gt;it was a spoiler and if it extended from both survaces it was an
air
&gt;&gt;brake. Seems dubious to me.
&gt;&gt;
&gt;&gt;Tony V LS6-b &quot;6N&quot;
&gt;&gt;
&gt;

[Lew Hartswick]

Ralph Jones wrote:
> Variometer American Heritage Dictionary
>
> A variable inductor used to measure variations in terrestrial
> magnetism.
>
> rj
I would say that the "American Heritage Dictionary" has abslutely
no electronic knowledge then. :-)
...lew...

[Nyal Williams[_2_]]

I'll bet that definition and that instrument are both older than ours --
nad more widespread, probably.

At 14:39 19 May 2008, Lew Hartswick wrote:
&gt;Ralph Jones wrote:
&gt;&gt; Variometer American Heritage Dictionary
&gt;&gt;
&gt;&gt; A variable inductor used to measure variations in terrestrial
&gt;&gt; magnetism.
&gt;&gt;
&gt;&gt; rj
&gt;I would say that the &quot;American Heritage Dictionary&quot; has
abslutely
&gt;no electronic knowledge then. :-)
&gt; ...lew...
&gt;

[Tony Verhulst]

Nyal Williams wrote:
> I'll bet that definition and that instrument are both older than ours --
> nad more widespread, probably.


Ralph's point, IMHO, is that you don't go to a general dictionary to get
specialized information.

Tony V.
http://home.comcast.net/~verhulst/SOARING

[sisu1a]

On May 19, 5:25 pm, Tony Verhulst > wrote:
> Nyal Williams wrote:
> > I'll bet that definition and that instrument are both older than ours --
> > nad more widespread, probably.
>
> Ralph's point, IMHO, is that you don't go to a general dictionary to get
> specialized information.
>
> Tony V.http://home.comcast.net/~verhulst/SOARING

Furthermore, you may even want to look elsewhere for general
information. Websters is full of definitions like this:

Hill - "a raised elevation of land, smaller than a mountain"

Mountain - "a raised elevation of land, larger than a hill"

no joke.

Paul Hanson

[Peter Higgs]

Hi All, just to be pedantic... If you only partially deploy any device,
it has a different aerodynamic characteristic.....

The first stage of Flaps gives an increase in Lift.
Second Stage of Flaps gives Lift And Drag.
Final Stage of Flaps gives Huge amounts of Drag, without any more Lift.

A quick look at your 'Barn Doors' will give you a reasonable idea of
what is likely to happen... I cannot imagine that vertical airbrakes
would ever give an increase in lift, even if only just cracked open a
millimeter or so.

Pilot Pete


At 20:14 16 May 2008, Andy wrote:
>On May 16, 8:56=A0am, Mike wrote:
>> According the the original Glasser-Dirks owner's manual for a DG100G,
>> the sailplane has "spoilers".
>
>I suspect that the original owner's manual is written in German and
>that the word "spoilers" is not mentioned. I don't have my
>Schleicher manual here but I think they call them Klappen. Not being
>picky for the sake of it, but pointing out that "spoiler" was probably
>the word chosen by the translator not necessarily by the manufacturer.
>
>Andy
>
>

[Nyal Williams[_2_]]

At 02:32 20 May 2008, sisu1a wrote:
>On May 19, 5:25 pm, Tony Verhulst wrote:
>> Nyal Williams wrote:
>> > I'll bet that definition and that instrument are both older than
ours
>--
>> > nad more widespread, probably.
>>
>> Ralph's point, IMHO, is that you don't go to a general dictionary to
get
>> specialized information.
>>
>> Tony V.http://home.comcast.net/~verhulst/SOARING
>
>Furthermore, you may even want to look elsewhere for general
>information. Websters is full of definitions like this:
>
>Hill - "a raised elevation of land, smaller than a mountain"
>
>Mountain - "a raised elevation of land, larger than a hill"
>
>no joke.
>
>Paul Hanson

It defines gorse as furze and it defines furze as gorse with no further
explanations in either place.

My point was that the definition of a variometer is not the property of
the soaring community. ;-)

[sisu1a]

On May 20, 6:55 am, Nyal Williams > wrote:
> At 02:32 20 May 2008, sisu1a wrote:
>
>
>
> >On May 19, 5:25 pm, Tony Verhulst wrote:
> >> Nyal Williams wrote:
> >> > I'll bet that definition and that instrument are both older than
> ours
> >--
> >> > nad more widespread, probably.
>
> >> Ralph's point, IMHO, is that you don't go to a general dictionary to
> get
> >> specialized information.
>
> >> Tony V.http://home.comcast.net/~verhulst/SOARING
>
> >Furthermore, you may even want to look elsewhere for general
> >information. Websters is full of definitions like this:
>
> >Hill - "a raised elevation of land, smaller than a mountain"
>
> >Mountain - "a raised elevation of land, larger than a hill"
>
> >no joke.
>
> >Paul Hanson
>
> It defines gorse as furze and it defines furze as gorse with no further
> explanations in either place.
>
> My point was that the definition of a variometer is not the property of
> the soaring community. ;-)

Correct! It was the name of a short wave radio part (variable
inductance coil = variometer since around 1895) long before it was the
name for our sensitive VSI's. http://www.qsl.net/in3otd/variodes.html

Paul