negative dihedral

[Tina]

I understand how positive dihedral helps dynamic stability in
airplanes, but some big ones, like the Russian An 124 Condor, has a
pronounced negative dihedral -- the wings have a noticeable downward
slope.

Q1: Do those airplanes need active fly by wire controls to maintain
stability, or is something else at play that keeps them right side up?

Q2: Does anyone have a design rationalization for such a
configuration, as opposed to just zero dihedral? I can appreciate why
fighters have it -- they exploit lack of aerodynamic stability for
rapid maneuvers -- but transports that spend their whole life being
straight and level are another issue.

Note: I have not morphed into an Mx clone!

[Bob Noel]

In article >,
Tina > wrote:

> I understand how positive dihedral helps dynamic stability in
> airplanes, but some big ones, like the Russian An 124 Condor, has a
> pronounced negative dihedral -- the wings have a noticeable downward
> slope.
>
> Q1: Do those airplanes need active fly by wire controls to maintain
> stability, or is something else at play that keeps them right side up?
>
> Q2: Does anyone have a design rationalization for such a
> configuration, as opposed to just zero dihedral? I can appreciate why
> fighters have it -- they exploit lack of aerodynamic stability for
> rapid maneuvers -- but transports that spend their whole life being
> straight and level are another issue.
>
> Note: I have not morphed into an Mx clone!

Don't know why, but don't those transports with negative dihedral also have
wings above the hull? So those aircraft have the CG below the wings.

--
Bob Noel
(goodness, please trim replies!!!)

[Frank Olson]

Tina wrote:
> I understand how positive dihedral helps dynamic stability in
> airplanes, but some big ones, like the Russian An 124 Condor, has a
> pronounced negative dihedral -- the wings have a noticeable downward
> slope.
>
> Q1: Do those airplanes need active fly by wire controls to maintain
> stability, or is something else at play that keeps them right side up?
>
> Q2: Does anyone have a design rationalization for such a
> configuration, as opposed to just zero dihedral? I can appreciate why
> fighters have it -- they exploit lack of aerodynamic stability for
> rapid maneuvers -- but transports that spend their whole life being
> straight and level are another issue.
>
> Note: I have not morphed into an Mx clone!


"Negative dihedral" may have more to do with keeping the landing gear
legs shorter. I know that's how they solved the problem they
encountered with the longer gear legs required on the Avro Arrow. On
the original mock-ups, when they first tried to retract the main gear
legs, they "crunched together" with each other at the point where they
entered the fuselage.

Dihedral (whether "positive" or "negative") does tend to *add*
stability, not take it away. Fighter jets and large airliners use "fly
by wire" because the stick forces required to move the control surfaces
may be too much for the average pilot (or might cause a good deal of
fatigue which, on longer flights, could be detrimental to the safe
operation of the aircraft). "Fly by wire" does little toward enhancing
the overall stability of an aircraft. "Stability" has more to do with
the overall design of the aircraft (and it's intended use).

[Frank Olson]

Bob Noel wrote:
> In article >,
> Tina > wrote:
>
>> I understand how positive dihedral helps dynamic stability in
>> airplanes, but some big ones, like the Russian An 124 Condor, has a
>> pronounced negative dihedral -- the wings have a noticeable downward
>> slope.
>>
>> Q1: Do those airplanes need active fly by wire controls to maintain
>> stability, or is something else at play that keeps them right side up?
>>
>> Q2: Does anyone have a design rationalization for such a
>> configuration, as opposed to just zero dihedral? I can appreciate why
>> fighters have it -- they exploit lack of aerodynamic stability for
>> rapid maneuvers -- but transports that spend their whole life being
>> straight and level are another issue.
>>
>> Note: I have not morphed into an Mx clone!
>
> Don't know why, but don't those transports with negative dihedral also have
> wings above the hull? So those aircraft have the CG below the wings.
>


And large transport aircraft are amongst the most aerodynamically stable
aircraft to fly.

[[email protected]]

Tina > wrote:
> I understand how positive dihedral helps dynamic stability in
> airplanes, but some big ones, like the Russian An 124 Condor, has a
> pronounced negative dihedral -- the wings have a noticeable downward
> slope.

No idea of why or how it stays upright.

From the pictures I've seen of it in the air, most of that negative
dihedral seems to go away while flying.


--
Jim Pennino

Remove .spam.sux to reply.

[Tina]

On Jun 3, 7:56 pm, Frank Olson
> wrote:
> Tina wrote:
> > I understand how positive dihedral helps dynamic stability in
> > airplanes, but some big ones, like the Russian An 124 Condor, has a
> > pronounced negative dihedral -- the wings have a noticeable downward
> > slope.
>
> > Q1: Do those airplanes need active fly by wire controls to maintain
> > stability, or is something else at play that keeps them right side up?
>
> > Q2: Does anyone have a design rationalization for such a
> > configuration, as opposed to just zero dihedral? I can appreciate why
> > fighters have it -- they exploit lack of aerodynamic stability for
> > rapid maneuvers -- but transports that spend their whole life being
> > straight and level are another issue.
>
> > Note: I have not morphed into an Mx clone!
>
> "Negative dihedral" may have more to do with keeping the landing gear
> legs shorter. I know that's how they solved the problem they
> encountered with the longer gear legs required on the Avro Arrow. On
> the original mock-ups, when they first tried to retract the main gear
> legs, they "crunched together" with each other at the point where they
> entered the fuselage.
>
> Dihedral (whether "positive" or "negative") does tend to *add*
> stability, not take it away. Fighter jets and large airliners use "fly
> by wire" because the stick forces required to move the control surfaces
> may be too much for the average pilot (or might cause a good deal of
> fatigue which, on longer flights, could be detrimental to the safe
> operation of the aircraft). "Fly by wire" does little toward enhancing
> the overall stability of an aircraft. "Stability" has more to do with
> the overall design of the aircraft (and it's intended use).

well what occurred to me is, with negative dihedral, as one wing lifts
it generates MORE lift, while the wing going down generates less. I
thought that would encourage the roll, but maybe the wing design
itself somehow takes that into account..

[Steven P. McNicoll[_2_]]

"Tina" > wrote in message
...
>
> well what occurred to me is, with negative dihedral, as one wing lifts
> it generates MORE lift, while the wing going down generates less.
>

Why did that occur to you?

[More_Flaps]

On Jun 4, 12:30*pm, Tina > wrote:
> On Jun 3, 7:56 pm, Frank Olson
>
>
>
> > wrote:
> > Tina wrote:
> > > I understand how positive dihedral helps dynamic stability in
> > > airplanes, but some big ones, like the Russian An 124 Condor, has a
> > > pronounced negative dihedral -- the wings have a noticeable downward
> > > slope.
>
> > > Q1: Do those airplanes need active fly by wire controls to maintain
> > > stability, or is something else at play that keeps them right side up?
>
> > > Q2: Does anyone have a design rationalization *for such a
> > > configuration, as opposed to just zero dihedral? I can appreciate why
> > > fighters have it -- they exploit lack of aerodynamic stability for
> > > rapid *maneuvers -- but transports that spend their whole life being
> > > straight and level are another issue.
>
> > > Note: I have not morphed into an Mx clone!
>
> > "Negative dihedral" may have more to do with keeping the landing gear
> > legs shorter. *I know that's how they solved the problem they
> > encountered with the longer gear legs required on the Avro Arrow. *On
> > the original mock-ups, when they first tried to retract the main gear
> > legs, they "crunched together" with each other at the point where they
> > entered the fuselage.
>
> > Dihedral (whether "positive" or "negative") does tend to *add*
> > stability, not take it away. *Fighter jets and large airliners use "fly
> > by wire" because the stick forces required to move the control surfaces
> > may be too much for the average pilot (or might cause a good deal of
> > fatigue which, on longer flights, could be detrimental to the safe
> > operation of the aircraft). *"Fly by wire" does little toward enhancing
> > the overall stability of an aircraft. *"Stability" has more to do with
> > the overall design of the aircraft (and it's intended use).
>
> well what occurred to me is, with negative dihedral, as one wing lifts
> it generates MORE lift, while the wing going down generates less. I
> thought that would encourage the roll, but maybe the wing design
> itself somehow takes that into account..

To pionts: The swept wing also add roll stability and for heavy low CG
airgraft with high swept wings the anhedral may be large to reduce
excessive stability.

Cheers

[Kyle Boatright]

"Tina" > wrote in message
...
>I understand how positive dihedral helps dynamic stability in
> airplanes, but some big ones, like the Russian An 124 Condor, has a
> pronounced negative dihedral -- the wings have a noticeable downward
> slope.
>
> Q1: Do those airplanes need active fly by wire controls to maintain
> stability, or is something else at play that keeps them right side up?
>
> Q2: Does anyone have a design rationalization for such a
> configuration, as opposed to just zero dihedral? I can appreciate why
> fighters have it -- they exploit lack of aerodynamic stability for
> rapid maneuvers -- but transports that spend their whole life being
> straight and level are another issue.
>
> Note: I have not morphed into an Mx clone!

Dihedral (or anhedral - negative dihedral) are both used to reposition the
aircraft's Center of Lift (CL) vs the aircraft's CG. This effectively
creates a pendulum, which wants to stabilize with the heavy part at the
lowest possible position. Like a pendulum, relatively speaking, the farther
above the CG the CL is, the more stable an aircraft will be. The whole
"dihedral increases roll stability" issue is based around this, not
increased or decreased roll due to lifting forces stemming from the attitude
of the airplane. The roll forces which create stability are due to this
pendulum effect.

If you want a stable aircraft in roll, add as much dihedral as possible to
raise the CL. If you want an unstable aircraft, do the opposite. The
anhedral on some on high wing transports is probably designed to give a
desired amount of stability. Some level of stability is great for a
transport, but you don't want to create an aircraft so stable it requires
oversized ailerons to generate the desired roll rate.

KB

[Jay Maynard]

On 2008-06-04, Kyle Boatright > wrote:
> If you want a stable aircraft in roll, add as much dihedral as possible to
> raise the CL. If you want an unstable aircraft, do the opposite. The
> anhedral on some on high wing transports is probably designed to give a
> desired amount of stability. Some level of stability is great for a
> transport, but you don't want to create an aircraft so stable it requires
> oversized ailerons to generate the desired roll rate.

Don't forget, also, that the wing in flight may well be flexed upward by a
considerable amount compared to its position on the ground. Check out
inflight pictures of a B-52, and compare them to pictures of the same
aircraft on the ground, for a dramatic example. That anhedral you see on the
ground may well be a significant amount of dihedral at max gross in flight.
--
Jay Maynard, K5ZC http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
Fairmont, MN (FRM) (Yes, that's me!)
AMD Zodiac CH601XLi N55ZC (ordered 17 March, delivery 10 June)

[Bertie the Bunyip[_24_]]

Tina > wrote in news:d9fb071f-4d30-45c3-916d-
:

> I understand how positive dihedral helps dynamic stability in
> airplanes, but some big ones, like the Russian An 124 Condor, has a
> pronounced negative dihedral -- the wings have a noticeable downward
> slope.


That's called Anhedral..
>
> Q1: Do those airplanes need active fly by wire controls to maintain
> stability, or is something else at play that keeps them right side up?

Nope.

>
> Q2: Does anyone have a design rationalization for such a
> configuration, as opposed to just zero dihedral? I can appreciate why
> fighters have it -- they exploit lack of aerodynamic stability for
> rapid maneuvers -- but transports that spend their whole life being
> straight and level are another issue.


Well, the anhedral negates what can be excessive stability that comes
form the sweep of the wings. Sweep provides a very similar kind of
stability as does dihedral and the addition of anhedral negates some of
this and keeps the airplane form becoming so stable that it can't even
be maneuvered!
Most of the airplanes with pronounced anhedral are high wing and would
have parasol stability as well. The anhedral helps neutralise some of
that. Some low wing Russian jets have anhedral, but it's quite small
Their sweep is quite marked and the anhedral is there to ammeliarate
that. The 727 had a fairly radical sweep and you will notice, that
though it has dihedral it's very little compared to the 737 or similar.
>
> Note: I have not morphed into an Mx clone!
>

We'll know for sure if you tell me this answer is completely wrong
because your MSFS 172 doesn't have anhedral.


Bertie

[Bertie the Bunyip[_24_]]

Frank Olson > wrote in
news:3Wk1k.4381$C12.2615@pd7urf3no:

> Bob Noel wrote:
>> In article
>> >,
>> Tina > wrote:
>>
>>> I understand how positive dihedral helps dynamic stability in
>>> airplanes, but some big ones, like the Russian An 124 Condor, has a
>>> pronounced negative dihedral -- the wings have a noticeable downward
>>> slope.
>>>
>>> Q1: Do those airplanes need active fly by wire controls to maintain
>>> stability, or is something else at play that keeps them right side
>>> up?
>>>
>>> Q2: Does anyone have a design rationalization for such a
>>> configuration, as opposed to just zero dihedral? I can appreciate
>>> why fighters have it -- they exploit lack of aerodynamic stability
>>> for rapid maneuvers -- but transports that spend their whole life
>>> being straight and level are another issue.
>>>
>>> Note: I have not morphed into an Mx clone!
>>
>> Don't know why, but don't those transports with negative dihedral
>> also have wings above the hull? So those aircraft have the CG below
>> the wings.
>>
>
>
> And large transport aircraft are amongst the most aerodynamically
> stable aircraft to fly.


Actually, that's not the case in every sense. They're not very speed
stable, for instance and thye have other problems with two diferent
kinds of dutch roll, related to sweep, mostly.

Bertie

[Bertie the Bunyip[_24_]]

Tina > wrote in news:621fed62-d178-4edc-9850-
:

> On Jun 3, 7:56 pm, Frank Olson
> > wrote:
>> Tina wrote:
>> > I understand how positive dihedral helps dynamic stability in
>> > airplanes, but some big ones, like the Russian An 124 Condor, has a
>> > pronounced negative dihedral -- the wings have a noticeable
downward
>> > slope.
>>
>> > Q1: Do those airplanes need active fly by wire controls to maintain
>> > stability, or is something else at play that keeps them right side
up?
>>
>> > Q2: Does anyone have a design rationalization for such a
>> > configuration, as opposed to just zero dihedral? I can appreciate
why
>> > fighters have it -- they exploit lack of aerodynamic stability for
>> > rapid maneuvers -- but transports that spend their whole life
being
>> > straight and level are another issue.
>>
>> > Note: I have not morphed into an Mx clone!
>>
>> "Negative dihedral" may have more to do with keeping the landing gear
>> legs shorter. I know that's how they solved the problem they
>> encountered with the longer gear legs required on the Avro Arrow. On
>> the original mock-ups, when they first tried to retract the main gear
>> legs, they "crunched together" with each other at the point where
they
>> entered the fuselage.
>>
>> Dihedral (whether "positive" or "negative") does tend to *add*
>> stability, not take it away. Fighter jets and large airliners use
"fly
>> by wire" because the stick forces required to move the control
surfaces
>> may be too much for the average pilot (or might cause a good deal of
>> fatigue which, on longer flights, could be detrimental to the safe
>> operation of the aircraft). "Fly by wire" does little toward
enhancing
>> the overall stability of an aircraft. "Stability" has more to do
with
>> the overall design of the aircraft (and it's intended use).
>
> well what occurred to me is, with negative dihedral, as one wing lifts
> it generates MORE lift, while the wing going down generates less. I
> thought that would encourage the roll, but maybe the wing design
> itself somehow takes that into account..
>
>

Yes, if you had a striaght wing airplane like that it would tend to do
it left to its; own devices, but a swept wing airplane well tend to
resist yaw, and by association, roll by virtue of the sweep alone.



Bertie

[Tina]

On Jun 3, 10:25 pm, Bertie the Bunyip > wrote:
> Tina > wrote in news:d9fb071f-4d30-45c3-916d-
> :
>
> > I understand how positive dihedral helps dynamic stability in
> > airplanes, but some big ones, like the Russian An 124 Condor, has a
> > pronounced negative dihedral -- the wings have a noticeable downward
> > slope.
>
> That's called Anhedral..
>
>
>
> > Q1: Do those airplanes need active fly by wire controls to maintain
> > stability, or is something else at play that keeps them right side up?
>
> Nope.
>
>
>
> > Q2: Does anyone have a design rationalization for such a
> > configuration, as opposed to just zero dihedral? I can appreciate why
> > fighters have it -- they exploit lack of aerodynamic stability for
> > rapid maneuvers -- but transports that spend their whole life being
> > straight and level are another issue.
>
> Well, the anhedral negates what can be excessive stability that comes
> form the sweep of the wings. Sweep provides a very similar kind of
> stability as does dihedral and the addition of anhedral negates some of
> this and keeps the airplane form becoming so stable that it can't even
> be maneuvered!
> Most of the airplanes with pronounced anhedral are high wing and would
> have parasol stability as well. The anhedral helps neutralise some of
> that. Some low wing Russian jets have anhedral, but it's quite small
> Their sweep is quite marked and the anhedral is there to ammeliarate
> that. The 727 had a fairly radical sweep and you will notice, that
> though it has dihedral it's very little compared to the 737 or similar.
>
>
>
> > Note: I have not morphed into an Mx clone!
>
> We'll know for sure if you tell me this answer is completely wrong
> because your MSFS 172 doesn't have anhedral.
>
> Bertie

Only after a very hard landing would a 172 develop negative dihedral.
A Mooney, on the other hand, given the placement of the wheels, would
either increase its positive dihedral, or more likely, given how
strongly they are built, put a dent in the runway.

[Bertie the Bunyip[_24_]]

"Kyle Boatright" > wrote in
:

>
> "Tina" > wrote in message
> news:d9fb071f-4d30-45c3-916d-3e4c00f89d52@
34g2000hsh.googlegroups.com..
> .
>>I understand how positive dihedral helps dynamic stability in
>> airplanes, but some big ones, like the Russian An 124 Condor, has a
>> pronounced negative dihedral -- the wings have a noticeable downward
>> slope.
>>
>> Q1: Do those airplanes need active fly by wire controls to maintain
>> stability, or is something else at play that keeps them right side
>> up?
>>
>> Q2: Does anyone have a design rationalization for such a
>> configuration, as opposed to just zero dihedral? I can appreciate why
>> fighters have it -- they exploit lack of aerodynamic stability for
>> rapid maneuvers -- but transports that spend their whole life being
>> straight and level are another issue.
>>
>> Note: I have not morphed into an Mx clone!
>
> Dihedral (or anhedral - negative dihedral) are both used to reposition
> the aircraft's Center of Lift (CL) vs the aircraft's CG. This
> effectively creates a pendulum, which wants to stabilize with the
> heavy part at the lowest possible position. Like a pendulum,
> relatively speaking, the farther above the CG the CL is, the more
> stable an aircraft will be. The whole "dihedral increases roll
> stability" issue is based around this, not increased or decreased roll
> due to lifting forces stemming from the attitude of the airplane. The
> roll forces which create stability are due to this pendulum effect.
>
> If you want a stable aircraft in roll, add as much dihedral as
> possible to raise the CL. If you want an unstable aircraft, do the
> opposite. The anhedral on some on high wing transports is probably
> designed to give a desired amount of stability. Some level of
> stability is great for a transport, but you don't want to create an
> aircraft so stable it requires oversized ailerons to generate the
> desired roll rate.
>

All correct! Also, anhedral helps a bit with the high alt dutch roll
case. I'd have to go into a lengthy explanation to cover it all, but
suffice it to say that swept wing airplanes are subject to a roll yaw
reversal at high altitues that can get rather unpleasnt ( complet loss
of control) Most must fly with a yaw damper, which is a gyro-controlled
rudder input that keeps the thing going straight. Anhedral offers a non
mechanical ad to ammelierating this effect. In fact, the russians are
notoriously clever at this sort of thing, which is why thye have madly
maneuverable fighters with more or less conventional control systems
while contemporary western aircraft relied on computers to achieve the
same results.


Bertie


Bertie

[Kyle Boatright]

"Bertie the Bunyip" > wrote in message
...
> "Kyle Boatright" > wrote in
> :
>
>>
>> "Tina" > wrote in message
>> news:d9fb071f-4d30-45c3-916d-3e4c00f89d52@
> 34g2000hsh.googlegroups.com..
>> .
>>>I understand how positive dihedral helps dynamic stability in
>>> airplanes, but some big ones, like the Russian An 124 Condor, has a
>>> pronounced negative dihedral -- the wings have a noticeable downward
>>> slope.
>>>
>>> Q1: Do those airplanes need active fly by wire controls to maintain
>>> stability, or is something else at play that keeps them right side
>>> up?
>>>
>>> Q2: Does anyone have a design rationalization for such a
>>> configuration, as opposed to just zero dihedral? I can appreciate why
>>> fighters have it -- they exploit lack of aerodynamic stability for
>>> rapid maneuvers -- but transports that spend their whole life being
>>> straight and level are another issue.
>>>
>>> Note: I have not morphed into an Mx clone!
>>
>> Dihedral (or anhedral - negative dihedral) are both used to reposition
>> the aircraft's Center of Lift (CL) vs the aircraft's CG. This
>> effectively creates a pendulum, which wants to stabilize with the
>> heavy part at the lowest possible position. Like a pendulum,
>> relatively speaking, the farther above the CG the CL is, the more
>> stable an aircraft will be. The whole "dihedral increases roll
>> stability" issue is based around this, not increased or decreased roll
>> due to lifting forces stemming from the attitude of the airplane. The
>> roll forces which create stability are due to this pendulum effect.
>>
>> If you want a stable aircraft in roll, add as much dihedral as
>> possible to raise the CL. If you want an unstable aircraft, do the
>> opposite. The anhedral on some on high wing transports is probably
>> designed to give a desired amount of stability. Some level of
>> stability is great for a transport, but you don't want to create an
>> aircraft so stable it requires oversized ailerons to generate the
>> desired roll rate.
>>
>
> All correct! Also, anhedral helps a bit with the high alt dutch roll
> case. I'd have to go into a lengthy explanation to cover it all, but
> suffice it to say that swept wing airplanes are subject to a roll yaw
> reversal at high altitues that can get rather unpleasnt ( complet loss
> of control)

Yep. Early 707's had a big enough dutch roll problem that it resulted in
aircraft being lost. This brought forth a redesign of the vertical stab.

>Most must fly with a yaw damper, which is a gyro-controlled
> rudder input that keeps the thing going straight. Anhedral offers a non
> mechanical ad to ammelierating this effect. In fact, the russians are
> notoriously clever at this sort of thing, which is why thye have madly
> maneuverable fighters with more or less conventional control systems
> while contemporary western aircraft relied on computers to achieve the
> same results.
>
>
> Bertie
>
>
> Bertie

[Bertie the Bunyip[_24_]]

"Kyle Boatright" > wrote in
:

>
> "Bertie the Bunyip" > wrote in message
> ...
>> "Kyle Boatright" > wrote in
>> :
>>
>>>
>>> "Tina" > wrote in message
>>> news:d9fb071f-4d30-45c3-916d-3e4c00f89d52@
>> 34g2000hsh.googlegroups.com..
>>> .
>>>>I understand how positive dihedral helps dynamic stability in
>>>> airplanes, but some big ones, like the Russian An 124 Condor, has a
>>>> pronounced negative dihedral -- the wings have a noticeable
>>>> downward slope.
>>>>
>>>> Q1: Do those airplanes need active fly by wire controls to maintain
>>>> stability, or is something else at play that keeps them right side
>>>> up?
>>>>
>>>> Q2: Does anyone have a design rationalization for such a
>>>> configuration, as opposed to just zero dihedral? I can appreciate
>>>> why fighters have it -- they exploit lack of aerodynamic stability
>>>> for rapid maneuvers -- but transports that spend their whole life
>>>> being straight and level are another issue.
>>>>
>>>> Note: I have not morphed into an Mx clone!
>>>
>>> Dihedral (or anhedral - negative dihedral) are both used to
>>> reposition the aircraft's Center of Lift (CL) vs the aircraft's CG.
>>> This effectively creates a pendulum, which wants to stabilize with
>>> the heavy part at the lowest possible position. Like a pendulum,
>>> relatively speaking, the farther above the CG the CL is, the more
>>> stable an aircraft will be. The whole "dihedral increases roll
>>> stability" issue is based around this, not increased or decreased
>>> roll due to lifting forces stemming from the attitude of the
>>> airplane. The roll forces which create stability are due to this
>>> pendulum effect.
>>>
>>> If you want a stable aircraft in roll, add as much dihedral as
>>> possible to raise the CL. If you want an unstable aircraft, do the
>>> opposite. The anhedral on some on high wing transports is probably
>>> designed to give a desired amount of stability. Some level of
>>> stability is great for a transport, but you don't want to create an
>>> aircraft so stable it requires oversized ailerons to generate the
>>> desired roll rate.
>>>
>>
>> All correct! Also, anhedral helps a bit with the high alt dutch roll
>> case. I'd have to go into a lengthy explanation to cover it all, but
>> suffice it to say that swept wing airplanes are subject to a roll yaw
>> reversal at high altitues that can get rather unpleasnt ( complet
>> loss of control)
>
> Yep. Early 707's had a big enough dutch roll problem that it resulted
> in aircraft being lost. This brought forth a redesign of the vertical
> stab.
>

That's right. I never flew it but the guys who did said the high alt
departures were so violent as to be truly frightening.
The 727 was pretty wild if it lost its yaw dampers and the only cure was
to get down to where the mach margins were wide enough not to be an
issue. Fortunately I only ever had a double yaw damper failure in the
sim.



Bertie

[Bertie the Bunyip[_24_]]

Tina > wrote in news:28472a75-654d-447f-9317-
:

> On Jun 3, 10:25 pm, Bertie the Bunyip > wrote:
>> Tina > wrote in news:d9fb071f-4d30-45c3-916d-
>> :
>>
>> > I understand how positive dihedral helps dynamic stability in
>> > airplanes, but some big ones, like the Russian An 124 Condor, has a
>> > pronounced negative dihedral -- the wings have a noticeable
downward
>> > slope.
>>
>> That's called Anhedral..
>>
>>
>>
>> > Q1: Do those airplanes need active fly by wire controls to maintain
>> > stability, or is something else at play that keeps them right side
up?
>>
>> Nope.
>>
>>
>>
>> > Q2: Does anyone have a design rationalization for such a
>> > configuration, as opposed to just zero dihedral? I can appreciate
why
>> > fighters have it -- they exploit lack of aerodynamic stability for
>> > rapid maneuvers -- but transports that spend their whole life
being
>> > straight and level are another issue.
>>
>> Well, the anhedral negates what can be excessive stability that comes
>> form the sweep of the wings. Sweep provides a very similar kind of
>> stability as does dihedral and the addition of anhedral negates some
of
>> this and keeps the airplane form becoming so stable that it can't
even
>> be maneuvered!
>> Most of the airplanes with pronounced anhedral are high wing and
would
>> have parasol stability as well. The anhedral helps neutralise some of
>> that. Some low wing Russian jets have anhedral, but it's quite small
>> Their sweep is quite marked and the anhedral is there to ammeliarate
>> that. The 727 had a fairly radical sweep and you will notice, that
>> though it has dihedral it's very little compared to the 737 or
similar.
>>
>>
>>
>> > Note: I have not morphed into an Mx clone!
>>
>> We'll know for sure if you tell me this answer is completely wrong
>> because your MSFS 172 doesn't have anhedral.
>>
>> Bertie
>
> Only after a very hard landing would a 172 develop negative dihedral.
> A Mooney, on the other hand, given the placement of the wheels, would
> either increase its positive dihedral, or more likely, given how
> strongly they are built, put a dent in the runway.
>

I think there have been a couple of straight wing airplanes wiht
anhedral, but I can't picture one off the top of my head. Surely
everything that can be tried, has been tried at this stage!


Bertie

[Ken S. Tucker]

On Jun 3, 5:05 pm, wrote:
> Tina > wrote:
> > I understand how positive dihedral helps dynamic stability in
> > airplanes, but some big ones, like the Russian An 124 Condor, has a
> > pronounced negative dihedral -- the wings have a noticeable downward
> > slope.
>
> No idea of why or how it stays upright.
>
> From the pictures I've seen of it in the air, most of that negative
> dihedral seems to go away while flying.

Yup, here's an example.
http://www.google.com/search?hl=en&q=antonov&btnG=Google+Search
Ken

[More_Flaps]

On Jun 4, 2:30*pm, Tina > wrote:
> On Jun 3, 10:25 pm, Bertie the Bunyip > wrote:
>
>
>
> > Tina > wrote in news:d9fb071f-4d30-45c3-916d-
> > :
>
> > > I understand how positive dihedral helps dynamic stability in
> > > airplanes, but some big ones, like the Russian An 124 Condor, has a
> > > pronounced negative dihedral -- the wings have a noticeable downward
> > > slope.
>
> > That's called Anhedral..
>
> > > Q1: Do those airplanes need active fly by wire controls to maintain
> > > stability, or is something else at play that keeps them right side up?
>
> > Nope.
>
> > > Q2: Does anyone have a design rationalization *for such a
> > > configuration, as opposed to just zero dihedral? I can appreciate why
> > > fighters have it -- they exploit lack of aerodynamic stability for
> > > rapid *maneuvers -- but transports that spend their whole life being
> > > straight and level are another issue.
>
> > Well, the anhedral negates what can be excessive stability that comes
> > form the sweep of the wings. Sweep provides a very similar kind of
> > stability as does dihedral and the addition of anhedral negates some of
> > this and keeps the airplane form becoming so stable that it can't even
> > be maneuvered!
> > Most of the airplanes with pronounced anhedral are high wing and would
> > have parasol stability as well. The anhedral helps neutralise some of
> > that. Some low wing Russian jets have anhedral, but it's quite small
> > Their sweep is quite marked and the anhedral is there to ammeliarate
> > that. The 727 had a fairly radical sweep and you will notice, that
> > though it has dihedral it's very little compared to the 737 or similar.
>
> > > Note: I have not morphed into an Mx clone!
>
> > We'll know for sure if you tell me this answer is completely wrong
> > because your MSFS 172 doesn't have anhedral.
>
> > Bertie
>
> Only after a very hard landing would a 172 develop negative dihedral.
> A Mooney, on the other hand, given the placement of the wheels, would
> either increase its positive dihedral, or more likely, given how
> strongly they are built, put a dent in the runway.

With those struts I would expect polyanhedral!

Cheers

[Bertie the Bunyip[_24_]]

"Ken S. Tucker" > wrote in news:ce62c207-10e1-
:

> On Jun 3, 5:05 pm, wrote:
>> Tina > wrote:
>> > I understand how positive dihedral helps dynamic stability in
>> > airplanes, but some big ones, like the Russian An 124 Condor, has a
>> > pronounced negative dihedral -- the wings have a noticeable
downward
>> > slope.
>>
>> No idea of why or how it stays upright.
>>
>> From the pictures I've seen of it in the air, most of that negative
>> dihedral seems to go away while flying.
>
> Yup, here's an example.
> http://www.google.com/search?hl=en&q=antonov&btnG=Google+Search
> Ken

Oh well done there Ken.

Why don't you 'splain it using a paper airplane, some paper clips and a
can of sterno?

Bertie

[Tina]

On Jun 3, 11:35 pm, Bertie the Bunyip > wrote:
> Tina > wrote in news:28472a75-654d-447f-9317-
> :
>
>
>
>
>
> > On Jun 3, 10:25 pm, Bertie the Bunyip > wrote:
> >> Tina > wrote in news:d9fb071f-4d30-45c3-916d-
> >> :
>
> >> > I understand how positive dihedral helps dynamic stability in
> >> > airplanes, but some big ones, like the Russian An 124 Condor, has a
> >> > pronounced negative dihedral -- the wings have a noticeable
> downward
> >> > slope.
>
> >> That's called Anhedral..
>
> >> > Q1: Do those airplanes need active fly by wire controls to maintain
> >> > stability, or is something else at play that keeps them right side
> up?
>
> >> Nope.
>
> >> > Q2: Does anyone have a design rationalization for such a
> >> > configuration, as opposed to just zero dihedral? I can appreciate
> why
> >> > fighters have it -- they exploit lack of aerodynamic stability for
> >> > rapid maneuvers -- but transports that spend their whole life
> being
> >> > straight and level are another issue.
>
> >> Well, the anhedral negates what can be excessive stability that comes
> >> form the sweep of the wings. Sweep provides a very similar kind of
> >> stability as does dihedral and the addition of anhedral negates some
> of
> >> this and keeps the airplane form becoming so stable that it can't
> even
> >> be maneuvered!
> >> Most of the airplanes with pronounced anhedral are high wing and
> would
> >> have parasol stability as well. The anhedral helps neutralise some of
> >> that. Some low wing Russian jets have anhedral, but it's quite small
> >> Their sweep is quite marked and the anhedral is there to ammeliarate
> >> that. The 727 had a fairly radical sweep and you will notice, that
> >> though it has dihedral it's very little compared to the 737 or
> similar.
>
> >> > Note: I have not morphed into an Mx clone!
>
> >> We'll know for sure if you tell me this answer is completely wrong
> >> because your MSFS 172 doesn't have anhedral.
>
> >> Bertie
>
> > Only after a very hard landing would a 172 develop negative dihedral.
> > A Mooney, on the other hand, given the placement of the wheels, would
> > either increase its positive dihedral, or more likely, given how
> > strongly they are built, put a dent in the runway.
>
> I think there have been a couple of straight wing airplanes wiht
> anhedral, but I can't picture one off the top of my head. Surely
> everything that can be tried, has been tried at this stage!
>
> Bertie

The everything that can be tried had been tried notion is out of
fashion, I don't think the patent office will be closing anytime soon,
or that Ratan's Scaled Composites will be closing up his shop. You can
bet someone will be trying an airplane with one wing over the other
soon. What would you call such a thing -- a redundant winged airplane?
For sure, in these days of political correctness, it would not be
called bi, would it?

Where are my meds?

[Tina]

On Jun 4, 4:49 am, HARRY POTTER > wrote:
> Tina wrote:
> > I understand how positive dihedral helps dynamic stability in
> > airplanes, but some big ones, like the Russian An 124 Condor, has a
> > pronounced negative dihedral -- the wings have a noticeable downward
> > slope.
>
> > Q1: Do those airplanes need active fly by wire controls to maintain
> > stability, or is something else at play that keeps them right side up?
>
> > Q2: Does anyone have a design rationalization for such a
> > configuration, as opposed to just zero dihedral? I can appreciate why
> > fighters have it -- they exploit lack of aerodynamic stability for
> > rapid maneuvers -- but transports that spend their whole life being
> > straight and level are another issue.
>
> > Note: I have not morphed into an Mx clone!
>
> The AN124 does not have negative dihedral. It just looks that way when it's
> on the ground because the weight of the engines bends the wings so they
> look drooped down. Once it's in the air, the fuselage bends the wings the
> other way, so it actually does have dihedral.
>
> --http://onlinelogbook.net

Thanks -- didn't realize it was simply wing droop when they are not
developing lift. That's what happens when you fly in stiff winged
little airplanes, you start overlooking something as obvious as that.

[Bertie the Bunyip[_24_]]

Tina > wrote in news:d86791d1-d1cd-4256-8c9e-
:

> On Jun 3, 11:35 pm, Bertie the Bunyip > wrote:
>> Tina > wrote in news:28472a75-654d-447f-9317-
>> :
>>
>>
>>
>>
>>
>> > On Jun 3, 10:25 pm, Bertie the Bunyip > wrote:
>> >> Tina > wrote in news:d9fb071f-4d30-45c3-
916d-
>> >> :
>>
>> >> > I understand how positive dihedral helps dynamic stability in
>> >> > airplanes, but some big ones, like the Russian An 124 Condor,
has a
>> >> > pronounced negative dihedral -- the wings have a noticeable
>> downward
>> >> > slope.
>>
>> >> That's called Anhedral..
>>
>> >> > Q1: Do those airplanes need active fly by wire controls to
maintain
>> >> > stability, or is something else at play that keeps them right
side
>> up?
>>
>> >> Nope.
>>
>> >> > Q2: Does anyone have a design rationalization for such a
>> >> > configuration, as opposed to just zero dihedral? I can
appreciate
>> why
>> >> > fighters have it -- they exploit lack of aerodynamic stability
for
>> >> > rapid maneuvers -- but transports that spend their whole life
>> being
>> >> > straight and level are another issue.
>>
>> >> Well, the anhedral negates what can be excessive stability that
comes
>> >> form the sweep of the wings. Sweep provides a very similar kind of
>> >> stability as does dihedral and the addition of anhedral negates
some
>> of
>> >> this and keeps the airplane form becoming so stable that it can't
>> even
>> >> be maneuvered!
>> >> Most of the airplanes with pronounced anhedral are high wing and
>> would
>> >> have parasol stability as well. The anhedral helps neutralise some
of
>> >> that. Some low wing Russian jets have anhedral, but it's quite
small
>> >> Their sweep is quite marked and the anhedral is there to
ammeliarate
>> >> that. The 727 had a fairly radical sweep and you will notice, that
>> >> though it has dihedral it's very little compared to the 737 or
>> similar.
>>
>> >> > Note: I have not morphed into an Mx clone!
>>
>> >> We'll know for sure if you tell me this answer is completely wrong
>> >> because your MSFS 172 doesn't have anhedral.
>>
>> >> Bertie
>>
>> > Only after a very hard landing would a 172 develop negative
dihedral.
>> > A Mooney, on the other hand, given the placement of the wheels,
would
>> > either increase its positive dihedral, or more likely, given how
>> > strongly they are built, put a dent in the runway.
>>
>> I think there have been a couple of straight wing airplanes wiht
>> anhedral, but I can't picture one off the top of my head. Surely
>> everything that can be tried, has been tried at this stage!
>>
>> Bertie
>
> The everything that can be tried had been tried notion is out of
> fashion, I don't think the patent office will be closing anytime soon,
> or that Ratan's Scaled Composites will be closing up his shop. You can
> bet someone will be trying an airplane with one wing over the other
> soon. What would you call such a thing -- a redundant winged airplane?
> For sure, in these days of political correctness, it would not be
> called bi, would it?

Well, years ago a hypersonic bipe was looked at, believe it or not, but
even Beurt Rutan will tell you that none of his creations were
completely original. Not to detract from his talent, whihc is monstrous,
but there's nothing on any of his airplanes that hadn't been done
before. Even that mad boomerang has precedants and quite a lot of them
dating back to the first world war (Caproni). Getting it all arranged
right to make it go better than anything before it is his gift. Having
said that, Spaceship one was pretty unique, but you'll probably find
that mad recovery system was done in boost glider in an old issue of
American Aircraft Modeler or similar. I never cease to be astounded at
the massive number of airplanes constructed in th elast century and the
variety. it hardly seems possible sometimes that there were enough
people to make them all!


Bertie



Bertie
>
> Where are my meds?
>

[Bertie the Bunyip[_24_]]

HARRY POTTER > wrote in
:

> Tina wrote:
>
>> I understand how positive dihedral helps dynamic stability in
>> airplanes, but some big ones, like the Russian An 124 Condor, has a
>> pronounced negative dihedral -- the wings have a noticeable downward
>> slope.
>>
>> Q1: Do those airplanes need active fly by wire controls to maintain
>> stability, or is something else at play that keeps them right side
>> up?
>>
>> Q2: Does anyone have a design rationalization for such a
>> configuration, as opposed to just zero dihedral? I can appreciate why
>> fighters have it -- they exploit lack of aerodynamic stability for
>> rapid maneuvers -- but transports that spend their whole life being
>> straight and level are another issue.
>>
>> Note: I have not morphed into an Mx clone!
>
> The AN124 does not have negative dihedral.

That's right, it has anhedral.



It just looks that way when
> it's on the ground because the weight of the engines bends the wings
> so they look drooped down. Once it's in the air, the fuselage bends
> the wings the other way, so it actually does have dihedral.#


Nope.

Bertie
>

[Bertie the Bunyip[_24_]]

Tina > wrote in
:

> On Jun 4, 4:49 am, HARRY POTTER > wrote:
>> Tina wrote:
>> > I understand how positive dihedral helps dynamic stability in
>> > airplanes, but some big ones, like the Russian An 124 Condor, has a
>> > pronounced negative dihedral -- the wings have a noticeable
>> > downward slope.
>>
>> > Q1: Do those airplanes need active fly by wire controls to maintain
>> > stability, or is something else at play that keeps them right side
>> > up?
>>
>> > Q2: Does anyone have a design rationalization for such a
>> > configuration, as opposed to just zero dihedral? I can appreciate
>> > why fighters have it -- they exploit lack of aerodynamic stability
>> > for rapid maneuvers -- but transports that spend their whole life
>> > being straight and level are another issue.
>>
>> > Note: I have not morphed into an Mx clone!
>>
>> The AN124 does not have negative dihedral. It just looks that way
>> when it's on the ground because the weight of the engines bends the
>> wings so they look drooped down. Once it's in the air, the fuselage
>> bends the wings the other way, so it actually does have dihedral.
>>
>> --http://onlinelogbook.net
>
> Thanks -- didn't realize it was simply wing droop when they are not
> developing lift. That's what happens when you fly in stiff winged
> little airplanes, you start overlooking something as obvious as that.
>

http://www.youtube.com/watch?v=WJscAaKfr7A

Bertie

[Bertie the Bunyip[_24_]]

Bertie the Bunyip > wrote in news:Xns9AB3A5306F330****upropeeh@
208.90.168.18:

> Tina > wrote in
> :
>
>> On Jun 4, 4:49 am, HARRY POTTER > wrote:
>>> Tina wrote:
>>> > I understand how positive dihedral helps dynamic stability in
>>> > airplanes, but some big ones, like the Russian An 124 Condor, has
a
>>> > pronounced negative dihedral -- the wings have a noticeable
>>> > downward slope.
>>>
>>> > Q1: Do those airplanes need active fly by wire controls to
maintain
>>> > stability, or is something else at play that keeps them right side
>>> > up?
>>>
>>> > Q2: Does anyone have a design rationalization for such a
>>> > configuration, as opposed to just zero dihedral? I can appreciate
>>> > why fighters have it -- they exploit lack of aerodynamic stability
>>> > for rapid maneuvers -- but transports that spend their whole life
>>> > being straight and level are another issue.
>>>
>>> > Note: I have not morphed into an Mx clone!
>>>
>>> The AN124 does not have negative dihedral. It just looks that way
>>> when it's on the ground because the weight of the engines bends the
>>> wings so they look drooped down. Once it's in the air, the fuselage
>>> bends the wings the other way, so it actually does have dihedral.
>>>
>>> --http://onlinelogbook.net
>>
>> Thanks -- didn't realize it was simply wing droop when they are not
>> developing lift. That's what happens when you fly in stiff winged
>> little airplanes, you start overlooking something as obvious as that.
>>
>
> http://www.youtube.com/watch?v=WJscAaKfr7A


Ooops, that was a MSFS one.

Here's an actual aiplane taking off...


http://www.youtube.com/watch?v=BcyRybpRSbI&feature=related

Which clarly shows the sockpuppet is wrong.


Bertie

[Tina]

On Jun 4, 11:23 am, Bertie the Bunyip > wrote:
> Tina > wrote :
>
>
>
> > On Jun 4, 4:49 am, HARRY POTTER > wrote:
> >> Tina wrote:
> >> > I understand how positive dihedral helps dynamic stability in
> >> > airplanes, but some big ones, like the Russian An 124 Condor, has a
> >> > pronounced negative dihedral -- the wings have a noticeable
> >> > downward slope.
>
> >> > Q1: Do those airplanes need active fly by wire controls to maintain
> >> > stability, or is something else at play that keeps them right side
> >> > up?
>
> >> > Q2: Does anyone have a design rationalization for such a
> >> > configuration, as opposed to just zero dihedral? I can appreciate
> >> > why fighters have it -- they exploit lack of aerodynamic stability
> >> > for rapid maneuvers -- but transports that spend their whole life
> >> > being straight and level are another issue.
>
> >> > Note: I have not morphed into an Mx clone!
>
> >> The AN124 does not have negative dihedral. It just looks that way
> >> when it's on the ground because the weight of the engines bends the
> >> wings so they look drooped down. Once it's in the air, the fuselage
> >> bends the wings the other way, so it actually does have dihedral.
>
> >> --http://onlinelogbook.net
>
> > Thanks -- didn't realize it was simply wing droop when they are not
> > developing lift. That's what happens when you fly in stiff winged
> > little airplanes, you start overlooking something as obvious as that.
>
> http://www.youtube.com/watch?v=WJscAaKfr7A
>
> Bertie

OK, I see some of the downslope was washed out in flight, but it was
still obvious there. Thanks

I expect more is washed out when the airplane is at gross weight, but
your point is made, Bertie.

[Bertie the Bunyip[_24_]]

Tina > wrote in
:

> On Jun 4, 11:23 am, Bertie the Bunyip > wrote:
>> Tina > wrote
>> innews:4cc0ec37-d80c-4006-9190-

>> m:
>>
>>
>>
>> > On Jun 4, 4:49 am, HARRY POTTER > wrote:
>> >> Tina wrote:
>> >> > I understand how positive dihedral helps dynamic stability in
>> >> > airplanes, but some big ones, like the Russian An 124 Condor,
>> >> > has a pronounced negative dihedral -- the wings have a
>> >> > noticeable downward slope.
>>
>> >> > Q1: Do those airplanes need active fly by wire controls to
>> >> > maintain stability, or is something else at play that keeps them
>> >> > right side up?
>>
>> >> > Q2: Does anyone have a design rationalization for such a
>> >> > configuration, as opposed to just zero dihedral? I can
>> >> > appreciate why fighters have it -- they exploit lack of
>> >> > aerodynamic stability for rapid maneuvers -- but transports
>> >> > that spend their whole life being straight and level are another
>> >> > issue.
>>
>> >> > Note: I have not morphed into an Mx clone!
>>
>> >> The AN124 does not have negative dihedral. It just looks that way
>> >> when it's on the ground because the weight of the engines bends
>> >> the wings so they look drooped down. Once it's in the air, the
>> >> fuselage bends the wings the other way, so it actually does have
>> >> dihedral.
>>
>> >> --http://onlinelogbook.net
>>
>> > Thanks -- didn't realize it was simply wing droop when they are not
>> > developing lift. That's what happens when you fly in stiff winged
>> > little airplanes, you start overlooking something as obvious as
>> > that.
>>
>> http://www.youtube.com/watch?v=WJscAaKfr7A
>>
>> Bertie
>
> OK, I see some of the downslope was washed out in flight, but it was
> still obvious there. Thanks
>
> I expect more is washed out when the airplane is at gross weight, but
> your point is made, Bertie.
>

Um, washout is probably not the best term, being share with another
important wing feature, but yeah, it's still there even when the
airplane is very heavy. I've seen the 225 fly and it's the same. There'a
also the little BAe 146 and the C5 and the C141 and the other little bay
antonov etc. I also mentioned I had seen some striaght wing airplanes
with anhedral but couldn't remember where. Most of the turboprop
antonovs have anhedral, but not nearly as much as the jets. He obviously
liked his airplanes to be manueverable!
Even a lot of the low wing jets had anhedral. The IL 62, for
instance.and IIRC some of the Tupovlevs also had it.

[Tina]

On Jun 4, 12:03 pm, Bertie the Bunyip > wrote:
> Tina > wrote :
>
> > On Jun 4, 11:23 am, Bertie the Bunyip > wrote:
> >> Tina > wrote
> >> innews:4cc0ec37-d80c-4006-9190-
>
>
>
>
>
> >> m:
>
> >> > On Jun 4, 4:49 am, HARRY POTTER > wrote:
> >> >> Tina wrote:
> >> >> > I understand how positive dihedral helps dynamic stability in
> >> >> > airplanes, but some big ones, like the Russian An 124 Condor,
> >> >> > has a pronounced negative dihedral -- the wings have a
> >> >> > noticeable downward slope.
>
> >> >> > Q1: Do those airplanes need active fly by wire controls to
> >> >> > maintain stability, or is something else at play that keeps them
> >> >> > right side up?
>
> >> >> > Q2: Does anyone have a design rationalization for such a
> >> >> > configuration, as opposed to just zero dihedral? I can
> >> >> > appreciate why fighters have it -- they exploit lack of
> >> >> > aerodynamic stability for rapid maneuvers -- but transports
> >> >> > that spend their whole life being straight and level are another
> >> >> > issue.
>
> >> >> > Note: I have not morphed into an Mx clone!
>
> >> >> The AN124 does not have negative dihedral. It just looks that way
> >> >> when it's on the ground because the weight of the engines bends
> >> >> the wings so they look drooped down. Once it's in the air, the
> >> >> fuselage bends the wings the other way, so it actually does have
> >> >> dihedral.
>
> >> >> --http://onlinelogbook.net
>
> >> > Thanks -- didn't realize it was simply wing droop when they are not
> >> > developing lift. That's what happens when you fly in stiff winged
> >> > little airplanes, you start overlooking something as obvious as
> >> > that.
>
> >>http://www.youtube.com/watch?v=WJscAaKfr7A
>
> >> Bertie
>
> > OK, I see some of the downslope was washed out in flight, but it was
> > still obvious there. Thanks
>
> > I expect more is washed out when the airplane is at gross weight, but
> > your point is made, Bertie.
>
> Um, washout is probably not the best term, being share with another
> important wing feature, but yeah, it's still there even when the
> airplane is very heavy. I've seen the 225 fly and it's the same. There'a
> also the little BAe 146 and the C5 and the C141 and the other little bay
> antonov etc. I also mentioned I had seen some striaght wing airplanes
> with anhedral but couldn't remember where. Most of the turboprop
> antonovs have anhedral, but not nearly as much as the jets. He obviously
> liked his airplanes to be manueverable!
> Even a lot of the low wing jets had anhedral. The IL 62, for
> instance.and IIRC some of the Tupovlevs also had it.

There was a country music guy who had a Mitsubishi twin with what I
remember looked liked pronounced anhedral, but I did a web search and
couldn't find a photo of it. What I am remembering might have been in
the 1970s.

There's little doubt in my mind that a high wing configuration with
negative dihedral would be more stable than a low winged one -- the cg
being way under the center of lift would see to that -- but still
don't have a 'model' to explain why wing sweep is a factor: when I
have some time I'll think about that, or I suppose I could ask
Anthony.

As for new stuff in aviation? I'd say GPS, released to the general
public during the RR presidency because of the Koran jet shootdown in
Russia, is fairly new. And let us not forget the new and improved FAA.

I'm doing my part to add to the recreation in rec.aviation (and trying
to not have it be wreck.aviation).

[Bertie the Bunyip[_24_]]

Tina > wrote in
:

> On Jun 4, 12:03 pm, Bertie the Bunyip > wrote:
>> Tina > wrote
>> innews:57ee2ec3-c172-4f53-96a3-cec87ee7be22
@k37g2000hsf.googlegroups.c
>> om:
>>
>> > On Jun 4, 11:23 am, Bertie the Bunyip > wrote:
>> >> Tina > wrote
>> >> innews:4cc0ec37-d80c-4006-9190-
>>
>>
>>
>>
>>
>> >> m:
>>
>> >> > On Jun 4, 4:49 am, HARRY POTTER > wrote:
>> >> >> Tina wrote:
>> >> >> > I understand how positive dihedral helps dynamic stability in
>> >> >> > airplanes, but some big ones, like the Russian An 124 Condor,
>> >> >> > has a pronounced negative dihedral -- the wings have a
>> >> >> > noticeable downward slope.
>>
>> >> >> > Q1: Do those airplanes need active fly by wire controls to
>> >> >> > maintain stability, or is something else at play that keeps
>> >> >> > them right side up?
>>
>> >> >> > Q2: Does anyone have a design rationalization for such a
>> >> >> > configuration, as opposed to just zero dihedral? I can
>> >> >> > appreciate why fighters have it -- they exploit lack of
>> >> >> > aerodynamic stability for rapid maneuvers -- but transports
>> >> >> > that spend their whole life being straight and level are
>> >> >> > another issue.
>>
>> >> >> > Note: I have not morphed into an Mx clone!
>>
>> >> >> The AN124 does not have negative dihedral. It just looks that
>> >> >> way when it's on the ground because the weight of the engines
>> >> >> bends the wings so they look drooped down. Once it's in the
>> >> >> air, the fuselage bends the wings the other way, so it actually
>> >> >> does have dihedral.
>>
>> >> >> --http://onlinelogbook.net
>>
>> >> > Thanks -- didn't realize it was simply wing droop when they are
>> >> > not developing lift. That's what happens when you fly in stiff
>> >> > winged little airplanes, you start overlooking something as
>> >> > obvious as that.
>>
>> >>http://www.youtube.com/watch?v=WJscAaKfr7A
>>
>> >> Bertie
>>
>> > OK, I see some of the downslope was washed out in flight, but it
>> > was still obvious there. Thanks
>>
>> > I expect more is washed out when the airplane is at gross weight,
>> > but your point is made, Bertie.
>>
>> Um, washout is probably not the best term, being share with another
>> important wing feature, but yeah, it's still there even when the
>> airplane is very heavy. I've seen the 225 fly and it's the same.
>> There'a also the little BAe 146 and the C5 and the C141 and the other
>> little bay antonov etc. I also mentioned I had seen some striaght
>> wing airplanes with anhedral but couldn't remember where. Most of the
>> turboprop antonovs have anhedral, but not nearly as much as the jets.
>> He obviously liked his airplanes to be manueverable!
>> Even a lot of the low wing jets had anhedral. The IL 62, for
>> instance.and IIRC some of the Tupovlevs also had it.
>
> There was a country music guy who had a Mitsubishi twin with what I
> remember looked liked pronounced anhedral, but I did a web search and
> couldn't find a photo of it. What I am remembering might have been in
> the 1970s.
>
> There's little doubt in my mind that a high wing configuration with
> negative dihedral would be more stable than a low winged one -- the cg
> being way under the center of lift would see to that -- but still
> don't have a 'model' to explain why wing sweep is a factor: when I
> have some time I'll think about that, or I suppose I could ask
> Anthony.
>
> As for new stuff in aviation? I'd say GPS, released to the general
> public during the RR presidency because of the Koran jet shootdown in
> Russia, is fairly new. And let us not forget the new and improved FAA.

FAA hs nothing to do with aviation! And as for GPS, it's just a tidied
up and warmed up version of a lot of older distance measured based stuff
like decca and to a lesser extent, tacan, so it's not really new, just a
more advanced and more precise system with the stations placed in space
instead of higgildy-piggildy over the landscape. It's real hard to find
something new under the sun! i can't think of anything earlier than
Decca here, but I'm sure that even that's based on something that
Polynesian sailors or somebody were doing 4,000 years ago!

Bertie
>
> I'm doing my part to add to the recreation in rec.aviation (and trying
> to not have it be wreck.aviation).
>

[Tina]

On Jun 4, 12:30 pm, Bertie the Bunyip > wrote:
> Tina > wrote :
>
> > On Jun 4, 12:03 pm, Bertie the Bunyip > wrote:
> >> Tina > wrote
> >> innews:57ee2ec3-c172-4f53-96a3-cec87ee7be22
>
> @k37g2000hsf.googlegroups.c
>
>
>
> >> om:
>
> >> > On Jun 4, 11:23 am, Bertie the Bunyip > wrote:
> >> >> Tina > wrote
> >> >> innews:4cc0ec37-d80c-4006-9190-
>
> >>
>
> >> >> m:
>
> >> >> > On Jun 4, 4:49 am, HARRY POTTER > wrote:
> >> >> >> Tina wrote:
> >> >> >> > I understand how positive dihedral helps dynamic stability in
> >> >> >> > airplanes, but some big ones, like the Russian An 124 Condor,
> >> >> >> > has a pronounced negative dihedral -- the wings have a
> >> >> >> > noticeable downward slope.
>
> >> >> >> > Q1: Do those airplanes need active fly by wire controls to
> >> >> >> > maintain stability, or is something else at play that keeps
> >> >> >> > them right side up?
>
> >> >> >> > Q2: Does anyone have a design rationalization for such a
> >> >> >> > configuration, as opposed to just zero dihedral? I can
> >> >> >> > appreciate why fighters have it -- they exploit lack of
> >> >> >> > aerodynamic stability for rapid maneuvers -- but transports
> >> >> >> > that spend their whole life being straight and level are
> >> >> >> > another issue.
>
> >> >> >> > Note: I have not morphed into an Mx clone!
>
> >> >> >> The AN124 does not have negative dihedral. It just looks that
> >> >> >> way when it's on the ground because the weight of the engines
> >> >> >> bends the wings so they look drooped down. Once it's in the
> >> >> >> air, the fuselage bends the wings the other way, so it actually
> >> >> >> does have dihedral.
>
> >> >> >> --http://onlinelogbook.net
>
> >> >> > Thanks -- didn't realize it was simply wing droop when they are
> >> >> > not developing lift. That's what happens when you fly in stiff
> >> >> > winged little airplanes, you start overlooking something as
> >> >> > obvious as that.
>
> >> >>http://www.youtube.com/watch?v=WJscAaKfr7A
>
> >> >> Bertie
>
> >> > OK, I see some of the downslope was washed out in flight, but it
> >> > was still obvious there. Thanks
>
> >> > I expect more is washed out when the airplane is at gross weight,
> >> > but your point is made, Bertie.
>
> >> Um, washout is probably not the best term, being share with another
> >> important wing feature, but yeah, it's still there even when the
> >> airplane is very heavy. I've seen the 225 fly and it's the same.
> >> There'a also the little BAe 146 and the C5 and the C141 and the other
> >> little bay antonov etc. I also mentioned I had seen some striaght
> >> wing airplanes with anhedral but couldn't remember where. Most of the
> >> turboprop antonovs have anhedral, but not nearly as much as the jets.
> >> He obviously liked his airplanes to be manueverable!
> >> Even a lot of the low wing jets had anhedral. The IL 62, for
> >> instance.and IIRC some of the Tupovlevs also had it.
>
> > There was a country music guy who had a Mitsubishi twin with what I
> > remember looked liked pronounced anhedral, but I did a web search and
> > couldn't find a photo of it. What I am remembering might have been in
> > the 1970s.
>
> > There's little doubt in my mind that a high wing configuration with
> > negative dihedral would be more stable than a low winged one -- the cg
> > being way under the center of lift would see to that -- but still
> > don't have a 'model' to explain why wing sweep is a factor: when I
> > have some time I'll think about that, or I suppose I could ask
> > Anthony.
>
> > As for new stuff in aviation? I'd say GPS, released to the general
> > public during the RR presidency because of the Koran jet shootdown in
> > Russia, is fairly new. And let us not forget the new and improved FAA.
>
> FAA hs nothing to do with aviation! And as for GPS, it's just a tidied
> up and warmed up version of a lot of older distance measured based stuff
> like decca and to a lesser extent, tacan, so it's not really new, just a
> more advanced and more precise system with the stations placed in space
> instead of higgildy-piggildy over the landscape. It's real hard to find
> something new under the sun! i can't think of anything earlier than
> Decca here, but I'm sure that even that's based on something that
> Polynesian sailors or somebody were doing 4,000 years ago!
>
> Bertie
>

I have a friend who works for an unnamed branch of the Federal
Government who said he could tell you what really is new in aviation,
but then he said he'd have to kill you,

then shred you,

and put what's left into a burn bag.

So the question before us is, should Bertie be briefed in?


This is how you can tell who your real friends are, Bertie.

[Bertie the Bunyip[_24_]]

Tina > wrote in
:

> On Jun 4, 12:30 pm, Bertie the Bunyip > wrote:
>> Tina > wrote
>> innews:db192ddb-52dd-4693-a681-b4f949b66053
@m3g2000hsc.googlegroups.co
>> m:
>>
>> > On Jun 4, 12:03 pm, Bertie the Bunyip > wrote:
>> >> Tina > wrote
>> >> innews:57ee2ec3-c172-4f53-96a3-cec87ee7be22
>>
>> @k37g2000hsf.googlegroups.c
>>
>>
>>
>> >> om:
>>
>> >> > On Jun 4, 11:23 am, Bertie the Bunyip > wrote:
>> >> >> Tina > wrote
>> >> >> innews:4cc0ec37-d80c-4006-9190-
>>
>> >>
>>
>> >> >> m:
>>
>> >> >> > On Jun 4, 4:49 am, HARRY POTTER >
>> >> >> > wrote:
>> >> >> >> Tina wrote:
>> >> >> >> > I understand how positive dihedral helps dynamic stability
>> >> >> >> > in airplanes, but some big ones, like the Russian An 124
>> >> >> >> > Condor, has a pronounced negative dihedral -- the wings
>> >> >> >> > have a noticeable downward slope.
>>
>> >> >> >> > Q1: Do those airplanes need active fly by wire controls to
>> >> >> >> > maintain stability, or is something else at play that
>> >> >> >> > keeps them right side up?
>>
>> >> >> >> > Q2: Does anyone have a design rationalization for such a
>> >> >> >> > configuration, as opposed to just zero dihedral? I can
>> >> >> >> > appreciate why fighters have it -- they exploit lack of
>> >> >> >> > aerodynamic stability for rapid maneuvers -- but
>> >> >> >> > transports that spend their whole life being straight and
>> >> >> >> > level are another issue.
>>
>> >> >> >> > Note: I have not morphed into an Mx clone!
>>
>> >> >> >> The AN124 does not have negative dihedral. It just looks
>> >> >> >> that way when it's on the ground because the weight of the
>> >> >> >> engines bends the wings so they look drooped down. Once it's
>> >> >> >> in the air, the fuselage bends the wings the other way, so
>> >> >> >> it actually does have dihedral.
>>
>> >> >> >> --http://onlinelogbook.net
>>
>> >> >> > Thanks -- didn't realize it was simply wing droop when they
>> >> >> > are not developing lift. That's what happens when you fly in
>> >> >> > stiff winged little airplanes, you start overlooking
>> >> >> > something as obvious as that.
>>
>> >> >>http://www.youtube.com/watch?v=WJscAaKfr7A
>>
>> >> >> Bertie
>>
>> >> > OK, I see some of the downslope was washed out in flight, but it
>> >> > was still obvious there. Thanks
>>
>> >> > I expect more is washed out when the airplane is at gross
>> >> > weight, but your point is made, Bertie.
>>
>> >> Um, washout is probably not the best term, being share with
>> >> another important wing feature, but yeah, it's still there even
>> >> when the airplane is very heavy. I've seen the 225 fly and it's
>> >> the same. There'a also the little BAe 146 and the C5 and the C141
>> >> and the other little bay antonov etc. I also mentioned I had seen
>> >> some striaght wing airplanes with anhedral but couldn't remember
>> >> where. Most of the turboprop antonovs have anhedral, but not
>> >> nearly as much as the jets. He obviously liked his airplanes to be
>> >> manueverable! Even a lot of the low wing jets had anhedral. The IL
>> >> 62, for instance.and IIRC some of the Tupovlevs also had it.
>>
>> > There was a country music guy who had a Mitsubishi twin with what I
>> > remember looked liked pronounced anhedral, but I did a web search
>> > and couldn't find a photo of it. What I am remembering might have
>> > been in the 1970s.
>>
>> > There's little doubt in my mind that a high wing configuration with
>> > negative dihedral would be more stable than a low winged one -- the
>> > cg being way under the center of lift would see to that -- but
>> > still don't have a 'model' to explain why wing sweep is a factor:
>> > when I have some time I'll think about that, or I suppose I could
>> > ask Anthony.
>>
>> > As for new stuff in aviation? I'd say GPS, released to the general
>> > public during the RR presidency because of the Koran jet shootdown
>> > in Russia, is fairly new. And let us not forget the new and
>> > improved FAA.
>>
>> FAA hs nothing to do with aviation! And as for GPS, it's just a
>> tidied up and warmed up version of a lot of older distance measured
>> based stuff like decca and to a lesser extent, tacan, so it's not
>> really new, just a more advanced and more precise system with the
>> stations placed in space instead of higgildy-piggildy over the
>> landscape. It's real hard to find something new under the sun! i
>> can't think of anything earlier than Decca here, but I'm sure that
>> even that's based on something that Polynesian sailors or somebody
>> were doing 4,000 years ago!
>>
>> Bertie
>>
>
> I have a friend who works for an unnamed branch of the Federal
> Government who said he could tell you what really is new in aviation,
> but then he said he'd have to kill you,
>
> then shred you,
>
> and put what's left into a burn bag.
>
> So the question before us is, should Bertie be briefed in?
>
>
> This is how you can tell who your real friends are, Bertie.
>
>
>

Heh heh. I'm insatiably curious so I'm tempted! But unless he's talking
about antigravity, you could probably trace some bit of whatever bit of
airplane he's talking about back to some point way back. In fact, even
if he were talking about antigravity, it's probably got soem of it's
roots in something the Nazis were playing with in Prague or one of
Tesla's half mad notions...


Bertie

[Tina]

On Jun 4, 2:15 pm, Bertie the Bunyip > wrote:
> Tina > wrote :
>
> > On Jun 4, 12:30 pm, Bertie the Bunyip > wrote:
> >> Tina > wrote
> >> innews:db192ddb-52dd-4693-a681-b4f949b66053
>
> @m3g2000hsc.googlegroups.co
>
>
>
> >> m:
>
> >> > On Jun 4, 12:03 pm, Bertie the Bunyip > wrote:
> >> >> Tina > wrote
> >> >> innews:57ee2ec3-c172-4f53-96a3-cec87ee7be22
>
> >> @k37g2000hsf.googlegroups.c
>
> >> >> om:
>
> >> >> > On Jun 4, 11:23 am, Bertie the Bunyip > wrote:
> >> >> >> Tina > wrote
> >> >> >> innews:4cc0ec37-d80c-4006-9190-
>
> >> >>
>
> >> >> >> m:
>
> >> >> >> > On Jun 4, 4:49 am, HARRY POTTER >
> >> >> >> > wrote:
> >> >> >> >> Tina wrote:
> >> >> >> >> > I understand how positive dihedral helps dynamic stability
> >> >> >> >> > in airplanes, but some big ones, like the Russian An 124
> >> >> >> >> > Condor, has a pronounced negative dihedral -- the wings
> >> >> >> >> > have a noticeable downward slope.
>
> >> >> >> >> > Q1: Do those airplanes need active fly by wire controls to
> >> >> >> >> > maintain stability, or is something else at play that
> >> >> >> >> > keeps them right side up?
>
> >> >> >> >> > Q2: Does anyone have a design rationalization for such a
> >> >> >> >> > configuration, as opposed to just zero dihedral? I can
> >> >> >> >> > appreciate why fighters have it -- they exploit lack of
> >> >> >> >> > aerodynamic stability for rapid maneuvers -- but
> >> >> >> >> > transports that spend their whole life being straight and
> >> >> >> >> > level are another issue.
>
> >> >> >> >> > Note: I have not morphed into an Mx clone!
>
> >> >> >> >> The AN124 does not have negative dihedral. It just looks
> >> >> >> >> that way when it's on the ground because the weight of the
> >> >> >> >> engines bends the wings so they look drooped down. Once it's
> >> >> >> >> in the air, the fuselage bends the wings the other way, so
> >> >> >> >> it actually does have dihedral.
>
> >> >> >> >> --http://onlinelogbook.net
>
> >> >> >> > Thanks -- didn't realize it was simply wing droop when they
> >> >> >> > are not developing lift. That's what happens when you fly in
> >> >> >> > stiff winged little airplanes, you start overlooking
> >> >> >> > something as obvious as that.
>
> >> >> >>http://www.youtube.com/watch?v=WJscAaKfr7A
>
> >> >> >> Bertie
>
> >> >> > OK, I see some of the downslope was washed out in flight, but it
> >> >> > was still obvious there. Thanks
>
> >> >> > I expect more is washed out when the airplane is at gross
> >> >> > weight, but your point is made, Bertie.
>
> >> >> Um, washout is probably not the best term, being share with
> >> >> another important wing feature, but yeah, it's still there even
> >> >> when the airplane is very heavy. I've seen the 225 fly and it's
> >> >> the same. There'a also the little BAe 146 and the C5 and the C141
> >> >> and the other little bay antonov etc. I also mentioned I had seen
> >> >> some striaght wing airplanes with anhedral but couldn't remember
> >> >> where. Most of the turboprop antonovs have anhedral, but not
> >> >> nearly as much as the jets. He obviously liked his airplanes to be
> >> >> manueverable! Even a lot of the low wing jets had anhedral. The IL
> >> >> 62, for instance.and IIRC some of the Tupovlevs also had it.
>
> >> > There was a country music guy who had a Mitsubishi twin with what I
> >> > remember looked liked pronounced anhedral, but I did a web search
> >> > and couldn't find a photo of it. What I am remembering might have
> >> > been in the 1970s.
>
> >> > There's little doubt in my mind that a high wing configuration with
> >> > negative dihedral would be more stable than a low winged one -- the
> >> > cg being way under the center of lift would see to that -- but
> >> > still don't have a 'model' to explain why wing sweep is a factor:
> >> > when I have some time I'll think about that, or I suppose I could
> >> > ask Anthony.
>
> >> > As for new stuff in aviation? I'd say GPS, released to the general
> >> > public during the RR presidency because of the Koran jet shootdown
> >> > in Russia, is fairly new. And let us not forget the new and
> >> > improved FAA.
>
> >> FAA hs nothing to do with aviation! And as for GPS, it's just a
> >> tidied up and warmed up version of a lot of older distance measured
> >> based stuff like decca and to a lesser extent, tacan, so it's not
> >> really new, just a more advanced and more precise system with the
> >> stations placed in space instead of higgildy-piggildy over the
> >> landscape. It's real hard to find something new under the sun! i
> >> can't think of anything earlier than Decca here, but I'm sure that
> >> even that's based on something that Polynesian sailors or somebody
> >> were doing 4,000 years ago!
>
> >> Bertie
>
> > I have a friend who works for an unnamed branch of the Federal
> > Government who said he could tell you what really is new in aviation,
> > but then he said he'd have to kill you,
>
> > then shred you,
>
> > and put what's left into a burn bag.
>
> > So the question before us is, should Bertie be briefed in?
>
> > This is how you can tell who your real friends are, Bertie.
>
> Heh heh. I'm insatiably curious so I'm tempted! But unless he's talking
> about antigravity, you could probably trace some bit of whatever bit of
> airplane he's talking about back to some point way back. In fact, even
> if he were talking about antigravity, it's probably got soem of it's
> roots in something the Nazis were playing with in Prague or one of
> Tesla's half mad notions...
>
> Bertie

In cases like these the argument "I knew that anyhow"when standing on
the threshold of the shredder don't hold a lot of water.

Actually what we are seeing academically is the need for face to face
meetings is beginning to diminish. We worry in the shrink world about
standardized observations in clinical trials, and are getting good
results with teleconferencing instead of having our 'standardized'
observer go to different sites to view subjects. The new thing might
very well be a reduction in business related air travel.

That is also becoming a reality in hi tech business. We are seeing
teleconferencing as effective as meeting face to face, at a great
saving of time and money. Teleconferencing will not, however, replace
the annual two week trip across the country with customers located
about 500 miles apart -- so easy to do by sel, and so difficult most
other ways. We do need to find a potential customer to visit in
Jackson Hole, Las Vegas, and near Lake Tahoe. (You do your business
planning your way, we'll do ours our way).

[Vaughn Simon]

"Tina" > wrote in message
...
> There was a country music guy who had a Mitsubishi twin with what I
> remember looked liked pronounced anhedral, but I did a web search and
> couldn't find a photo of it. What I am remembering might have been in
> the 1970s.

Mitsubishi MU2, from the nice folks who brought us the Zero. This phote shows
the apparent anhedral: http://tinyurl.com/5rhlka

Vaughn

[Scott Skylane]

Bertie the Bunyip wrote:


>>
>>http://www.youtube.com/watch?v=WJscAaKfr7A
>
>
>
> Ooops, that was a MSFS one. <----------
/snip/

Am I the only one who sees the *immense* irony in this?

Happy Flying!
Scott Skylane

[Bertie the Bunyip[_24_]]

Scott Skylane > wrote in news:Z5-
ions:

> Bertie the Bunyip wrote:
>
>
>>>
>>>http://www.youtube.com/watch?v=WJscAaKfr7A
>>
>>
>>
>> Ooops, that was a MSFS one. <----------
> /snip/
>
> Am I the only one who sees the *immense* irony in this?

Nope.

Bertie

[Maxwell[_2_]]

"Bertie the Bunyip" > wrote in message
...
>
> Actually, that's not the case in every sense. They're not very speed
> stable, for instance and thye have other problems with two diferent
> kinds of dutch roll, related to sweep, mostly.
>
> Bertie

Keep guessing wannabe, got a link?

[Bertie the Bunyip[_25_]]

"Maxwell" <luv2^fly99@cox.^net> wrote in news:9aF1k.1876$nD3.800
@newsfe15.lga:

>
> "Bertie the Bunyip" > wrote in message
> ...
>>
>> Actually, that's not the case in every sense. They're not very speed
>> stable, for instance and thye have other problems with two diferent
>> kinds of dutch roll, related to sweep, mostly.
>>
>> Bertie
>
> Keep guessing wannabe, got a link?
>
>
>

Nope. Don't need one.



Bertie

[Maxwell[_2_]]

"Bertie the Bunyip" > wrote in message
...
>
> Yes, if you had a striaght wing airplane like that it would tend to do
> it left to its; own devices, but a swept wing airplane well tend to
> resist yaw, and by association, roll by virtue of the sweep alone.
>
>
>
> Bertie

Sure it does Bertie Buttlipp, you know everything, you know everyone, you've
done everything. Gotta link?

[Bertie the Bunyip[_25_]]

"Maxwell" <luv2^fly99@cox.^net> wrote in
:

>
> "Bertie the Bunyip" > wrote in message
> ...
>>
>> Yes, if you had a striaght wing airplane like that it would tend to
>> do it left to its; own devices, but a swept wing airplane well tend
>> to resist yaw, and by association, roll by virtue of the sweep alone.
>>
>>
>>
>> Bertie
>
> Sure it does Bertie Buttlipp, you know everything, you know everyone,
> you've done everything. Gotta link?
>
>
>
Don't need one. I know everything, remember?


Bertie

[Maxwell[_2_]]

"Bertie the Bunyip" > wrote in message
...
>
> Why don't you 'splain it using a paper airplane, some paper clips and a
> can of sterno?
>
> Bertie

Why don't you buy a book. Can't read? Thought so.

[Maxwell[_2_]]

"Bertie the Bunyip" > wrote in message
...

>
> All correct! Also, anhedral helps a bit with the high alt dutch roll
> case. I'd have to go into a lengthy explanation to cover it all, but
> suffice it to say that swept wing airplanes are subject to a roll yaw
> reversal at high altitues that can get rather unpleasnt ( complet loss
> of control) Most must fly with a yaw damper, which is a gyro-controlled
> rudder input that keeps the thing going straight. Anhedral offers a non
> mechanical ad to ammelierating this effect. In fact, the russians are
> notoriously clever at this sort of thing, which is why thye have madly
> maneuverable fighters with more or less conventional control systems
> while contemporary western aircraft relied on computers to achieve the
> same results.
>
>
> Bertie

WOW! Buttlipps, that's waaay coool. Do you have to like soak your head in
cold water after such radical processing? Cooling or something?

[Maxwell[_2_]]

"Bertie the Bunyip" > wrote in message
...
>
> That's right. I never flew it but the guys who did said ............
>
>
> Bertie

Starting to sound like your little brother Anthony.

[Bertie the Bunyip[_25_]]

"Maxwell" <luv2^fly99@cox.^net> wrote in news:DhF1k.1882$nD3.1558
@newsfe15.lga:

>
> "Bertie the Bunyip" > wrote in message
> ...
>>
>> Well, years ago a hypersonic bipe was looked at, believe it or not,
but
>> even Beurt Rutan will tell you that none of his creations were
>> completely original. Not to detract from his talent, whihc is
monstrous,
>> but there's nothing on any of his airplanes that hadn't been done
>> before. Even that mad boomerang has precedants and quite a lot of
them
>> dating back to the first world war (Caproni). Getting it all arranged
>> right to make it go better than anything before it is his gift.
Having
>> said that, Spaceship one was pretty unique, but you'll probably find
>> that mad recovery system was done in boost glider in an old issue of
>> American Aircraft Modeler or similar. I never cease to be astounded
at
>> the massive number of airplanes constructed in th elast century and
the
>> variety. it hardly seems possible sometimes that there were enough
>> people to make them all!
>>
>>
>> Bertie
>>
>
> Absolutely amazing!!!!!!!!!!!!
>
>
>

Thenkew.

Bertie

[Maxwell[_2_]]

"Bertie the Bunyip" > wrote in message
...
>
> I think there have been a couple of straight wing airplanes wiht
> anhedral, but I can't picture one off the top of my head. Surely
> everything that can be tried, has been tried at this stage!
>
>
> Bertie

Have you tried a lobotomy?

[Bertie the Bunyip[_25_]]

"Maxwell" <luv2^fly99@cox.^net> wrote in news:ygF1k.1881$nD3.539
@newsfe15.lga:

>
> "Bertie the Bunyip" > wrote in message
> ...
>>
>> I think there have been a couple of straight wing airplanes wiht
>> anhedral, but I can't picture one off the top of my head. Surely
>> everything that can be tried, has been tried at this stage!
>>
>>
>> Bertie
>
> Have you tried a lobotomy?
>
>
>

No. Will I make lots of blank poasts and continue to fight absolutely
lost causes afterwards?


Bertie

[Maxwell[_2_]]

"Bertie the Bunyip" > wrote in message
...
>
> Well, years ago a hypersonic bipe was looked at, believe it or not, but
> even Beurt Rutan will tell you that none of his creations were
> completely original. Not to detract from his talent, whihc is monstrous,
> but there's nothing on any of his airplanes that hadn't been done
> before. Even that mad boomerang has precedants and quite a lot of them
> dating back to the first world war (Caproni). Getting it all arranged
> right to make it go better than anything before it is his gift. Having
> said that, Spaceship one was pretty unique, but you'll probably find
> that mad recovery system was done in boost glider in an old issue of
> American Aircraft Modeler or similar. I never cease to be astounded at
> the massive number of airplanes constructed in th elast century and the
> variety. it hardly seems possible sometimes that there were enough
> people to make them all!
>
>
> Bertie
>

Absolutely amazing!!!!!!!!!!!!

[Bertie the Bunyip[_25_]]

"Maxwell" <luv2^fly99@cox.^net> wrote in news:icF1k.1878$nD3.255
@newsfe15.lga:

>
> "Bertie the Bunyip" > wrote in message
> ...
>>
>> Why don't you 'splain it using a paper airplane, some paper clips and
a
>> can of sterno?
>>
>> Bertie
>
> Why don't you buy a book. Can't read? Thought so.
>
>

Oh ouch!
Siding with Tucker. I have been soooo served!
Bwwahwhahwhahwhahhwhahwhahw!



Bertie

[Maxwell[_2_]]

"Scott Skylane" > wrote in message
ions...
> Bertie the Bunyip wrote:
>
>
>>>
>>>http://www.youtube.com/watch?v=WJscAaKfr7A
>>
>>
>>
>> Ooops, that was a MSFS one. <----------
> /snip/
>
> Am I the only one who sees the *immense* irony in this?
>
> Happy Flying!
> Scott Skylane

Apparently something he and Anthony have been working on.

[Bertie the Bunyip[_25_]]

"Maxwell" <luv2^fly99@cox.^net> wrote in news:DeF1k.1880$nD3.1544
@newsfe15.lga:

>
> "Bertie the Bunyip" > wrote in message
> ...
>>
>> That's right. I never flew it but the guys who did said ............
>>
>>
>> Bertie
>
> Starting to sound like your little brother Anthony.
>

Oh ouch.. Anthony lames. What next, you going to call me a poopie head?

Bertie

[Maxwell[_2_]]

"Bertie the Bunyip" > wrote in message
...
>>
>
> Heh heh. I'm insatiably curious so I'm tempted! But unless he's talking
> about antigravity, you could probably trace some bit of whatever bit of
> airplane he's talking about back to some point way back. In fact, even
> if he were talking about antigravity, it's probably got soem of it's
> roots in something the Nazis were playing with in Prague or one of
> Tesla's half mad notions...
>
>
> Bertie

WOW! Have you told Dudley and MoreFlaps?

[Bertie the Bunyip[_25_]]

"Maxwell" <luv2^fly99@cox.^net> wrote in news:hiF1k.1883$nD3.1442
@newsfe15.lga:

>
> "Scott Skylane" > wrote in message
> ions...
>> Bertie the Bunyip wrote:
>>
>>
>>>>
>>>>http://www.youtube.com/watch?v=WJscAaKfr7A
>>>
>>>
>>>
>>> Ooops, that was a MSFS one. <----------
>> /snip/
>>
>> Am I the only one who sees the *immense* irony in this?
>>
>> Happy Flying!
>> Scott Skylane
>
> Apparently something he and Anthony have been working on.
>
>
>

Yeh, good one lamer boi.


You're giving me a real hiding there. Keep up the good work.



Bertie

[Bertie the Bunyip[_25_]]

"Maxwell" <luv2^fly99@cox.^net> wrote in news:RjF1k.1884$nD3.1610
@newsfe15.lga:

>
> "Bertie the Bunyip" > wrote in message
> ...
>>>
>>
>> Heh heh. I'm insatiably curious so I'm tempted! But unless he's
talking
>> about antigravity, you could probably trace some bit of whatever bit
of
>> airplane he's talking about back to some point way back. In fact,
even
>> if he were talking about antigravity, it's probably got soem of it's
>> roots in something the Nazis were playing with in Prague or one of
>> Tesla's half mad notions...
>>
>>
>> Bertie
>
> WOW! Have you told Dudley and MoreFlaps?


No, do I need to?



Bertie

[Rich Ahrens[_2_]]

on 6/3/2008 10:35 PM Bertie the Bunyip said the following:
> I think there have been a couple of straight wing airplanes wiht
> anhedral, but I can't picture one off the top of my head. Surely
> everything that can be tried, has been tried at this stage!

The Lockheed F-104, perhaps?

[Bertie the Bunyip[_24_]]

Rich Ahrens > wrote in news:484753e0$0$76834
:

> on 6/3/2008 10:35 PM Bertie the Bunyip said the following:
>> I think there have been a couple of straight wing airplanes wiht
>> anhedral, but I can't picture one off the top of my head. Surely
>> everything that can be tried, has been tried at this stage!
>
> The Lockheed F-104, perhaps?
>

Yep, dats one. i have no idea what the anhedral does on that, but I'm going
to take a blind stab at area rule.

Bertie

[Rich Ahrens[_2_]]

on 6/4/2008 9:54 PM Bertie the Bunyip said the following:
> Rich Ahrens > wrote in news:484753e0$0$76834
> :
>
>> on 6/3/2008 10:35 PM Bertie the Bunyip said the following:
>>> I think there have been a couple of straight wing airplanes wiht
>>> anhedral, but I can't picture one off the top of my head. Surely
>>> everything that can be tried, has been tried at this stage!
>> The Lockheed F-104, perhaps?
>>
>
> Yep, dats one. i have no idea what the anhedral does on that, but I'm going
> to take a blind stab at area rule.

The usual, I think - Dutch roll control. The vertical fin was almost as
long as the wings.

[Bertie the Bunyip[_24_]]

Rich Ahrens > wrote in
. net:

> on 6/4/2008 9:54 PM Bertie the Bunyip said the following:
>> Rich Ahrens > wrote in news:484753e0$0$76834
>> :
>>
>>> on 6/3/2008 10:35 PM Bertie the Bunyip said the following:
>>>> I think there have been a couple of straight wing airplanes wiht
>>>> anhedral, but I can't picture one off the top of my head. Surely
>>>> everything that can be tried, has been tried at this stage!
>>> The Lockheed F-104, perhaps?
>>>
>>
>> Yep, dats one. i have no idea what the anhedral does on that, but I'm
>> going to take a blind stab at area rule.
>
> The usual, I think - Dutch roll control. The vertical fin was almost
> as long as the wings.
>

Mm. Dunno. The fin would be neccesary because of the center of pressure
change anyway. You're right though. anhedral would dampen any high
speed dutch roll tendencies by reducing the alpha on an advancing wing.,
but the rules for things like that with razor thin wings get a bit weird
anyway. Trans-sonic it shouldn't have many issues anyway since
compressibility is dealt with by the airfoil, but you're probably right.
Its a shame. I was flying with a former aeronautical engineer the other
day and could have asked him.



Bertie

[Robert M. Gary]

On Jun 3, 3:13*pm, Tina > wrote:
> I understand how positive dihedral helps dynamic stability in
> airplanes, but some big ones, like the Russian An 124 Condor, has a
> pronounced negative dihedral -- the wings have a noticeable downward
> slope.
>
> Q1: Do those airplanes need active fly by wire controls to maintain
> stability, or is something else at play that keeps them right side up?
>
> Q2: Does anyone have a design rationalization *for such a
> configuration, as opposed to just zero dihedral? I can appreciate why
> fighters have it -- they exploit lack of aerodynamic stability for
> rapid *maneuvers -- but transports that spend their whole life being
> straight and level are another issue.

Negative dihedral provides a place to hang bombs ala the USNavy's A-7
Corsair II.

-Robert

[Blueskies]

"Robert M. Gary" > wrote in message
...
On Jun 3, 3:13 pm, Tina > wrote:
> I understand how positive dihedral helps dynamic stability in
> airplanes, but some big ones, like the Russian An 124 Condor, has a
> pronounced negative dihedral -- the wings have a noticeable downward
> slope.
>
> Q1: Do those airplanes need active fly by wire controls to maintain
> stability, or is something else at play that keeps them right side up?
>
> Q2: Does anyone have a design rationalization for such a
> configuration, as opposed to just zero dihedral? I can appreciate why
> fighters have it -- they exploit lack of aerodynamic stability for
> rapid maneuvers -- but transports that spend their whole life being
> straight and level are another issue.

Negative dihedral provides a place to hang bombs ala the USNavy's A-7
Corsair II.

-Robert



Don't forget the Harrier also...

[Ron Wanttaja]

On Wed, 4 Jun 2008 22:53:30 -0700 (PDT), "Robert M. Gary" >
wrote:

> > Q2: Does anyone have a design rationalization *for such a
> > configuration, as opposed to just zero dihedral? I can appreciate why
> > fighters have it -- they exploit lack of aerodynamic stability for
> > rapid *maneuvers -- but transports that spend their whole life being
> > straight and level are another issue.
>
> Negative dihedral provides a place to hang bombs ala the USNavy's A-7
> Corsair II.

Yeah, there's no way you could hang bombs on a wing with positive dihedral, like
the A-1 Skyraider. :-)

Ron Wanttaja

[Bertie the Bunyip[_24_]]

"Robert M. Gary" > wrote in news:fe88d496-d08f-4a7f-8a0a-
:

> On Jun 3, 3:13*pm, Tina > wrote:
>> I understand how positive dihedral helps dynamic stability in
>> airplanes, but some big ones, like the Russian An 124 Condor, has a
>> pronounced negative dihedral -- the wings have a noticeable downward
>> slope.
>>
>> Q1: Do those airplanes need active fly by wire controls to maintain
>> stability, or is something else at play that keeps them right side up?
>>
>> Q2: Does anyone have a design rationalization *for such a
>> configuration, as opposed to just zero dihedral? I can appreciate why
>> fighters have it -- they exploit lack of aerodynamic stability for
>> rapid *maneuvers -- but transports that spend their whole life being
>> straight and level are another issue.
>
> Negative dihedral provides a place to hang bombs ala the USNavy's A-7
> Corsair II.
>


Uh. OK



Bertie

[Maxwell[_2_]]

"Bertie the Bunyip" > wrote in message
...
> "Robert M. Gary" > wrote in news:fe88d496-d08f-4a7f-8a0a-
> :
>
>> On Jun 3, 3:13 pm, Tina > wrote:
>>> I understand how positive dihedral helps dynamic stability in
>>> airplanes, but some big ones, like the Russian An 124 Condor, has a
>>> pronounced negative dihedral -- the wings have a noticeable downward
>>> slope.
>>>
>>> Q1: Do those airplanes need active fly by wire controls to maintain
>>> stability, or is something else at play that keeps them right side up?
>>>
>>> Q2: Does anyone have a design rationalization for such a
>>> configuration, as opposed to just zero dihedral? I can appreciate why
>>> fighters have it -- they exploit lack of aerodynamic stability for
>>> rapid maneuvers -- but transports that spend their whole life being
>>> straight and level are another issue.
>>
>> Negative dihedral provides a place to hang bombs ala the USNavy's A-7
>> Corsair II.
>>
>
>
> Uh. OK
>
>
>
> Bertie

Relevance?
More compulsive behavior.
You reply even when you have no relevant answer.

[Bertie the Bunyip[_25_]]

"Maxwell" <luv2^fly99@cox.^net> wrote in
:

>
> "Bertie the Bunyip" > wrote in message
> ...
>> "Robert M. Gary" > wrote in
>> news:fe88d496-d08f-4a7f-8a0a-
>> :
>>
>>> On Jun 3, 3:13 pm, Tina > wrote:
>>>> I understand how positive dihedral helps dynamic stability in
>>>> airplanes, but some big ones, like the Russian An 124 Condor, has a
>>>> pronounced negative dihedral -- the wings have a noticeable
>>>> downward slope.
>>>>
>>>> Q1: Do those airplanes need active fly by wire controls to maintain
>>>> stability, or is something else at play that keeps them right side
>>>> up?
>>>>
>>>> Q2: Does anyone have a design rationalization for such a
>>>> configuration, as opposed to just zero dihedral? I can appreciate
>>>> why fighters have it -- they exploit lack of aerodynamic stability
>>>> for rapid maneuvers -- but transports that spend their whole life
>>>> being straight and level are another issue.
>>>
>>> Negative dihedral provides a place to hang bombs ala the USNavy's
>>> A-7 Corsair II.
>>>
>>
>>
>> Uh. OK
>>
>>
>>
>> Bertie
>
> Relevance?
> More compulsive behavior.
> You reply even when you have no relevant answer.


That's not compulsion, fjukkktard.





Bertie

[Bertie the Bunyip[_25_]]

"Maxwell" <luv2^fly99@cox.^net> wrote in news:wOU1k.3439$QI2.1788
@newsfe23.lga:

>
> "Bertie the Bunyip" > wrote in message
> ...
>> "Maxwell" <luv2^fly99@cox.^net> wrote in
>> :
>>
>>>
> .
>>
>>
>> That's not compulsion, fjukkktard.
>>
>>
>>
>>
>>
>> Bertie
>
> Sure it is Squirty the ****drip, you just can't stop.
>
>
>

Sure i can, There's a difference, PKB boi.


Bertie

[Maxwell[_2_]]

"Bertie the Bunyip" > wrote in message
...
> "Maxwell" <luv2^fly99@cox.^net> wrote in
> :
>
>>
..
>
>
> That's not compulsion, fjukkktard.
>
>
>
>
>
> Bertie

Sure it is Squirty the ****drip, you just can't stop.

[Bertie the Bunyip[_25_]]

"Maxwell" <luv2^fly99@cox.^net> wrote in
:

>
> "Bertie the Bunyip" > wrote in message
> .. .
>> "Maxwell" <luv2^fly99@cox.^net> wrote in news:wOU1k.3439$QI2.1788
>> @newsfe23.lga:
>>
>>>
>>>
>>
>> Sure i can, There's a difference, PKB boi.
>>
>>
>> Bertie
>
> Na ya can't, and no there isn't. I think you have a little to much
> anhedral between the ears.
>
>

Mebbe, mebbe not.

Don't matter, k00k.


Bertie

[Maxwell[_2_]]

"Bertie the Bunyip" > wrote in message
.. .
> "Maxwell" <luv2^fly99@cox.^net> wrote in news:wOU1k.3439$QI2.1788
> @newsfe23.lga:
>
>>
>>
>
> Sure i can, There's a difference, PKB boi.
>
>
> Bertie

Na ya can't, and no there isn't. I think you have a little to much anhedral
between the ears.

[Robert M. Gary]

On Jun 5, 6:54*am, Ron Wanttaja > wrote:

> Yeah, there's no way you could hang bombs on a wing with positive dihedral, like
> the A-1 Skyraider. :-)

Are you comparing the BB's that the A-1 carried with the real toys
that the A-7 held? ;)

-Robert

[Daryl Hunt[_3_]]

People, if you are going to answer any of the AUKk00ks, remove any mention
of any NG with the word "kook" in it. The AUKk00ks are actually harmless if
left to themselves.

"Bertie the Bunyip" > wrote in message
...
> "Maxwell" <luv2^fly99@cox.^net> wrote in
> :
>
>>
>> "Bertie the Bunyip" > wrote in message
>> ...
>>> "Robert M. Gary" > wrote in
>>> news:fe88d496-d08f-4a7f-8a0a-
>>> :
>>>
>>>> On Jun 3, 3:13 pm, Tina > wrote:
>>>>> I understand how positive dihedral helps dynamic stability in
>>>>> airplanes, but some big ones, like the Russian An 124 Condor, has a
>>>>> pronounced negative dihedral -- the wings have a noticeable
>>>>> downward slope.
>>>>>
>>>>> Q1: Do those airplanes need active fly by wire controls to maintain
>>>>> stability, or is something else at play that keeps them right side
>>>>> up?
>>>>>
>>>>> Q2: Does anyone have a design rationalization for such a
>>>>> configuration, as opposed to just zero dihedral? I can appreciate
>>>>> why fighters have it -- they exploit lack of aerodynamic stability
>>>>> for rapid maneuvers -- but transports that spend their whole life
>>>>> being straight and level are another issue.
>>>>
>>>> Negative dihedral provides a place to hang bombs ala the USNavy's
>>>> A-7 Corsair II.
>>>>
>>>
>>>
>>> Uh. OK
>>>
>>>
>>>
>>> Bertie
>>
>> Relevance?
>> More compulsive behavior.
>> You reply even when you have no relevant answer.
>
>
> That's not compulsion, fjukkktard.
>
>
>
>
>
> Bertie

** Posted from http://www.teranews.com **

[Bertie the Bunyip[_25_]]

"Daryl Hunt" > wrote in
:

> People, if you are going to answer any of the AUKk00ks, remove any
> mention of any NG with the word "kook" in it. The AUKk00ks are
> actually harmless if left to themselves.
>

And they're dangerous, when?


Bertie
>

[Robert M. Gary]

On Jun 5, 7:53*am, Bertie the Bunyip > wrote:
> "Robert M. Gary" > wrote in news:fe88d496-d08f-4a7f-8a0a-
> :

> > Negative dihedral provides a place to hang bombs ala the USNavy's A-7
> > Corsair II.
>
> Uh. OK

Well just think how embarrased you would be if you had the bombs on
the top of the wing.

-Robert

[Bertie the Bunyip[_24_]]

"Robert M. Gary" > wrote in
:

> On Jun 5, 7:53*am, Bertie the Bunyip > wrote:
>> "Robert M. Gary" > wrote in
>> news:fe88d496-d08f-4a7f-8a0a-
>
>> :
>
>> > Negative dihedral provides a place to hang bombs ala the USNavy's
>> > A-7 Corsair II.
>>
>> Uh. OK
>
> Well just think how embarrased you would be if you had the bombs on
> the top of the wing.
>

You have me there.


Bertie

[John Godwin]

"Robert M. Gary" > wrote in


> Negative dihedral provides a place to hang bombs ala the USNavy's
> A-7 Corsair II.

Hmmm. Our plane has positive dihedral and 2 hard points on each wing.

--

[Tina]

With all of the expert* pilots here, why would bombs on the top of the
wings be a problem? Go inverted, much better visibility toward the
ground then, right? Then release, they'll fall away.


*Expert: you have to take the word into its component parts: Ex is a
has been, and a spurt is a drip under pressure.




On Jun 6, 12:47 pm, "Robert M. Gary" > wrote:
> On Jun 5, 7:53 am, Bertie the Bunyip > wrote:
>
> > "Robert M. Gary" > wrote in news:fe88d496-d08f-4a7f-8a0a-
> > :
> > > Negative dihedral provides a place to hang bombs ala the USNavy's A-7
> > > Corsair II.
>
> > Uh. OK
>
> Well just think how embarrased you would be if you had the bombs on
> the top of the wing.
>
> -Robert

[Blueskies]

"Tina" > wrote in message ...
> With all of the expert* pilots here, why would bombs on the top of the
> wings be a problem? Go inverted, much better visibility toward the
> ground then, right? Then release, they'll fall away.
>
>
> *Expert: you have to take the word into its component parts: Ex is a
> has been, and a spurt is a drip under pressure.
>
>
>
>


Which way is up?

http://www.fas.org/man/dod-101/sys/ac/row/jaguar-solo_1024.jpg

[Tina]

On Jun 6, 7:14 pm, "Blueskies" > wrote:
> "Tina" > wrote in ...
> > With all of the expert* pilots here, why would bombs on the top of the
> > wings be a problem? Go inverted, much better visibility toward the
> > ground then, right? Then release, they'll fall away.
>
> > *Expert: you have to take the word into its component parts: Ex is a
> > has been, and a spurt is a drip under pressure.
>
> Which way is up?
>
> http://www.fas.org/man/dod-101/sys/ac/row/jaguar-solo_1024.jpg

Our airplane says no more than 30 degree pitch and 60 degree bank, so
we would not be putting bombs on the top of our wings. As for up? Who
here could you ask for reliable directions "Can you show me the way to
up, please?" That actually does raise some interesting questions --
it's far to subtle to matter to airplane flight, but I wonder how
accurately "up" can be measured, and how big is the average absolute
error compared to something starting at the exact center of the earth.
For that matter, how would you find the exact center?

[Blueskies]

"Blueskies" > wrote in message ...
>
> "Tina" > wrote in message
> ...
>> With all of the expert* pilots here, why would bombs on the top of the
>> wings be a problem? Go inverted, much better visibility toward the
>> ground then, right? Then release, they'll fall away.
>>
>>
>> *Expert: you have to take the word into its component parts: Ex is a
>> has been, and a spurt is a drip under pressure.
>>
>>
>>
>>
>
>
> Which way is up?
>
> http://www.fas.org/man/dod-101/sys/ac/row/jaguar-solo_1024.jpg
>
>
>

Actually, thinking about this again, doesn't "negative dihedral" mean you don't have the dihedral?

;-)

[Tina]

On Jun 6, 9:21 pm, "Blueskies" > wrote:
> "Blueskies" > wrote in m...
>
> > "Tina" > wrote in message
> ...
> >> With all of the expert* pilots here, why would bombs on the top of the
> >> wings be a problem? Go inverted, much better visibility toward the
> >> ground then, right? Then release, they'll fall away.
>
> >> *Expert: you have to take the word into its component parts: Ex is a
> >> has been, and a spurt is a drip under pressure.
>
> > Which way is up?
>
> >http://www.fas.org/man/dod-101/sys/ac/row/jaguar-solo_1024.jpg
>
> Actually, thinking about this again, doesn't "negative dihedral" mean you don't have the dihedral?
>
> ;-)

negative!