"Interesting" wind yesterday

[Jay Honeck]

As many may know, we set records here in Iowa yesterday, hitting 73 degrees
in Iowa City. It felt great!

The winds in the afternoon started to kick up pretty good, as a cold front
approached from the northwest. On our way back from brunch in Lone Rock, WI
(where we ran into this group's own Jim Burns, figuratively speaking. We
actually passed on the taxiway...) the wind was humming along at about 40
knots, right on the nose. It was smooth at 6500 feet, though, so Mary and
the kids were content to nap all the way home.

Iowa City AWOS was reporting 20 gusts to 26, but right down Rwy 25. As I
entered the pattern, however, it became very apparent that the winds at
pattern altitude were markedly different from the reported surface winds,
with a very strong southerly component that was pushing me in too close on
downwind.

As I turned from base to final, the unexpectedly strong wind had me bent out
of shape pretty good, but I managed to wrestle the runway back into
alignment without entering the coffin-corner of cross controlling.
Nevertheless, I was amazed to find that it was taking full left aileron and
right rudder to keep the runway in the windshield. This wind was clearly
NOT down the runway.

Asking Mary to get AWOS for me, the mechanical man was still reporting winds
at 240 -- perfect for Rwy 25. As I cursed the stupid AWOS equipment --
which was clearly malfunctioning (or so I thought) -- I told the kids to
hang on for a wild ride.

They weren't disappointed. On short final, it felt as if someone had kicked
up on the left wing from below with all their might, and we banked hard
(toward our hotel!) away from the runway. We were low, and slow, and things
didn't look good, but just as quickly as you can say it, I was able to right
us, and the wind was suddenly and instantly right down the runway.

Surprisingly, despite the wild approach, I continued my unexplained streak
of perfect landings, causing nary a squeak. Only difference was, this time
I was slightly out of breath, and I had a death-grip on the yoke... ;-)

Talk about wind shear. There was a nearly 90 degree difference in the wind
direction at MAYBE 500 feet (or less) off the ground. And both wind
"streams" were whistling right along, too.

Now today it's 35 degrees, and dropping like a stone -- with winds of well
over 30 knots.

Gotta love the Midwest in late winter!
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Jose]

> The combination of [...] and that great looking paint job
> left little doubt as to who it could be!

He painted his =airplane= purple??

Jose
--
Math is a game. The object of the game is to figure out the rules.
for Email, make the obvious change in the address.

[Jim Burns]

The front must have been approaching Iowa and northern IL faster than it was
here in Wisconsin. We stopped at Adams 63C on the way home for 32 gallons
of cheap $2.32 100 LL. On the way from LNR to 63C we did a "speed run" just
to check the Aztec's performance. Using the KLN 94, it calculated the winds
at 3500 ft to be from 200 at 14, surface winds were 240 at 6. 26" and 2400
RPMs gave us a TAS of 200mph, just shy of the always optimistic book figure
of 205mph.

The rest of the afternoon at STE winds were 240 at 6. Lots of planes out in
the nice weather, even a Luscumbe practicing crosswind landings. Later in
the evening it must have picked up, because a friend of mine reported flying
north from Prairie Du Chien in his C170 with a 150kt ground speed. Now it's
34011G22 and temps dropped from 53 yesterday to 27 now and still falling.
Rain, sleet, and snow all mixed. Spring in Wisconsin is spelled
SwPiRnItNeGr, because every other day is one or the other.

I was happy to see Jay and Mary taxi up in the Pathfinder and almost wished
we would have had the "slower" waitress so we could have met before we
cranked up the Aztec. The combination of Mary's voice on the radio, two
kids in the back seat, Jay with his camera, and that great looking paint job
left little doubt as to who it could be!

Jim

[Mike Rapoport]

"Jay Honeck" > wrote in message
news:OUZWd.42901$r55.23167@attbi_s52...
> As many may know, we set records here in Iowa yesterday, hitting 73
> degrees in Iowa City. It felt great!
>
> The winds in the afternoon started to kick up pretty good, as a cold front
> approached from the northwest. On our way back from brunch in Lone Rock,
> WI (where we ran into this group's own Jim Burns, figuratively speaking.
> We actually passed on the taxiway...) the wind was humming along at about
> 40 knots, right on the nose. It was smooth at 6500 feet, though, so Mary
> and the kids were content to nap all the way home.
>
> Iowa City AWOS was reporting 20 gusts to 26, but right down Rwy 25. As I
> entered the pattern, however, it became very apparent that the winds at
> pattern altitude were markedly different from the reported surface winds,
> with a very strong southerly component that was pushing me in too close on
> downwind.
>
> As I turned from base to final, the unexpectedly strong wind had me bent
> out of shape pretty good, but I managed to wrestle the runway back into
> alignment without entering the coffin-corner of cross controlling.
> Nevertheless, I was amazed to find that it was taking full left aileron
> and right rudder to keep the runway in the windshield. This wind was
> clearly NOT down the runway.
>
> Asking Mary to get AWOS for me, the mechanical man was still reporting
> winds at 240 -- perfect for Rwy 25. As I cursed the stupid AWOS
> equipment -- which was clearly malfunctioning (or so I thought) -- I told
> the kids to hang on for a wild ride.
>
> They weren't disappointed. On short final, it felt as if someone had
> kicked up on the left wing from below with all their might, and we banked
> hard (toward our hotel!) away from the runway. We were low, and slow, and
> things didn't look good, but just as quickly as you can say it, I was able
> to right us, and the wind was suddenly and instantly right down the
> runway.
>
> Surprisingly, despite the wild approach, I continued my unexplained streak
> of perfect landings, causing nary a squeak. Only difference was, this
> time I was slightly out of breath, and I had a death-grip on the yoke...
> ;-)
>
> Talk about wind shear. There was a nearly 90 degree difference in the
> wind direction at MAYBE 500 feet (or less) off the ground. And both wind
> "streams" were whistling right along, too.
>
> Now today it's 35 degrees, and dropping like a stone -- with winds of well
> over 30 knots.
>
> Gotta love the Midwest in late winter!
> --
> Jay Honeck
> Iowa City, IA
> Pathfinder N56993
> www.AlexisParkInn.com
> "Your Aviation Destination"


In NV, I remember flying along in smooth air with 130kts of wind at 19,000'
and hearing the AWOS saying "wind calm". You knew you were probably in for
a beating somewhere during the descent. The area had frequent inversions at
night and the wind would go from high speed to dead calm in a few hundred
vertical feet. I also experienced (over UT) winds from the east at 120kts
at FL290 and from the west at 25kts at FL250. I reported this and it wasn't
long before all the eastbound airliners were down at FL250. I wouldn't have
thought it possible before seeing it for myself. I always thought that
winds just filled low pressure areas from high pressure areas but
apparently, it is more complicated.

Mike
MU-2

[[email protected]]

it was a weird day (and night).
I was flying on the UW MedFlight Augusta 109 late Saturday night, early
Sunday am this weekend and on a flight to Mauston, and then later to
Viroqua, we were showing only 95-100 knots heading to the NW from
Madison.
On the way back, with a patient on board, we were doing about 205
knots! Which was a blessing with a sick patient on board, keeps the
time to a minimum.
The shear factor wasn't as big of a deal overnight, which is also a
blessing because the approach to the UW helipad is like flying into a
canyon. And now we have a crane on top of the hospital to worry
about...

Ryan Wubben
Madison, WI

[Milen Lazarov]

Jay Honeck wrote:

[cut]
> As I turned from base to final, the unexpectedly strong wind had me bent out
> of shape pretty good, but I managed to wrestle the runway back into
> alignment without entering the coffin-corner of cross controlling.
[cut]

What is a coffin-corner and how does one get into it in the pattern?

[Stefan]

Milen Lazarov wrote:

> Jay Honeck wrote:
>
>> As I turned from base to final, the unexpectedly strong wind had me
>> bent out of shape pretty good, but I managed to wrestle the runway
>> back into alignment without entering the coffin-corner of cross
>> controlling.

> What is a coffin-corner and how does one get into it in the pattern?

Jay frivolously used that well defined term completely wrong, presumably
just because it sounds good. (A tactic which some journalists use, too,
especially when they write about aviation...) You never get into the
coffin corner at pattern altitude.

The stall speed is constant with indicated airspeed, while Vne is
constant with true airspeed (acually, it decreases somewhat at high
altitudes). So there is a point, at very high altitudes, where Vs meets
Vne. This point is called the coffin corner, because you can't escape
from it (except by descending): You can't slow down (stall) nor
accelerate (Vne).

Stefan

[Jay Honeck]

> What is a coffin-corner and how does one get into it in the pattern?

The "coffin-corner" is where you end up when the wind is blowing you
out from the runway on your base-to-final turn.

Your instinct is to tighten the turn in an effort to keep the runway
aligned, and maybe help it along with some rudder. This can be
disastrous at slow speeds while close to the ground, since a stall/spin
can develop quickly, and you won't have sufficient altitude to recover.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Jim Burns]

Coffin Corner, Deadmans Corner: The turn from base leg to final leg on a
landing approach. If the pilot has overflown the runway centerline and
attempts to roll back to the runway centerline adverse yaw will tend to
point the nose of the airplane in the opposite direction of the turn, a
natural reaction will be to use rudder to point the nose at the runway.
When this doesn't work the pilot may increase the bank in the same
direction. As the airspeed decays, the he incorrectly applies more rudder
in the direction of the turn creating a slow rolling uncoordinated skidding
turn close to the ground. Roll combined with Yaw in the direction of the
roll with airspeed dropping is a great recipe for a spin. The fact that
this situation is close to the ground makes the spin nearly unrecoverable.

Jim

[Jim Burns]

I'll agree with Stefan that this term gets mixed usage. What Stefan refers
to is mainly a consideration for high altitude aircraft. The U2 is the
plane that instantly comes to mind. Think about pulling back, stall...
Think about pushing forward Vne.... not much room in between.

What I refered to in my response, I generally refer to as the Deadman's
Corner, it instills the seriousness of proper airspeed control,
coordination, and patience when teaching primary students proper landing
patterns.

Jim

[Montblack]

("Jay Honeck" wrote)
> Gotta love the Midwest in late winter!


We're calling it early spring. There was a memo.

Actually, we've had a 7 year run of pretty mild winters in the Twin Cities
beginning in 1998. Two years ago it reached 75F on St. Patrick's Day.

(1996 was brutal!!! - 40F/C for the first time ever in the Twin Cities)


Montblack

[Stefan]

Jim Burns wrote:

....
> natural reaction will be to use rudder to point the nose at the runway.
....

I've never understood this whole turn to final hype, and I've never
understood why such a reaction should be natural. All my instructors
kept hammering into my head: When in the circuit, never fly below the
yellow triangle (plus half the wind) and always be sure to fly
coordinated. That's what I've been doing since then, and I've never had
any problems.

Stefan

[Jim Burns]

> (1996 was brutal!!! - 40F/C for the first time ever in the Twin Cities)
>
>
> Montblack

Ah.... a little Merlot would make it feel all warm and toasty! :)

Jim

[Jim Burns]

Ahh.. you said the magic word... "circuit" and (just guessing the .ch) that
I can assume you are not from the US, please correct me if I'm wrong.

The FAA does not require spin training for private or commercial pilots but
instead puts emphasis on stall/spin awareness. One of the primary areas
being the base to final turn because you are low, slow and if uncoordinated,
in trouble. It's stressed on every written exam and in every oral exam that
I've had. They stress what a quartering tailwind can do to you while on
base leg, how it can blow you past the extended runway centerline and how
incorrect corrections can get a pilot in trouble. I've seen students
incorrectly use rudder to try to "get back" to the centerline, it is
something that an instructor has to be aware of, stay on top of, and like
you say, keep pounding it into the student because the student simply
forgets. The closer your pattern is to the runway, the angle created
becomes greater and at the same time creates an "urgent" situation for the
student. He now is faced with a discussion. This is where an instructor
must teach the student not to feel committed to the approach and to perform
a go around.

Now, here's one for you.... yellow triangle? airspeed marker?

Jim - CFII

[Stefan]

Jim Burns wrote:

> Ahh.. you said the magic word... "circuit" and (just guessing the .ch) that
> I can assume you are not from the US, please correct me if I'm wrong.

No, you're absolutely correct. But believe me, the aerodynamics work
excatly the same on this side of the pond!

> being the base to final turn because you are low, slow and if uncoordinated,
> in trouble.

That's the point: Low, yes, but you are *never* slow and uncoordinated
at this point. Never. *This* has become my primary "natural" reaction.
But then, I've learnt how to use a rudder at day one.

> Now, here's one for you.... yellow triangle? airspeed marker?

Doesn't this exist in the USA? Yellow triangle on the airspeed
indicator: Recommended minimum approach speed. (Something like 1.3 Vs at
MTOW and landing configuration or some such.) Drop below this at the
checkride, and you are invited to show up for a second try.

Stefan

[Jim Burns]

Nope, no yellow triangle on the airspeed indicator unless the pilot or his
instructor choose to put one there. Not a requirement. We do use 1.3Vs as
an approach speed, but it normally isn't marked.

It sounds like you've got a good approach method, one easily duplicated for
students here in the US, includeing the yellow triangle.

I believe that MOST aerodynamics work the same on your side of the pond,
sans one.... the $$$ needed to create lift are higher on your side of the
pond! :)

Jim

[Mike Rapoport]

"Stefan" > wrote in message
...
> Jim Burns wrote:
>>
> Doesn't this exist in the USA? Yellow triangle on the airspeed indicator:
> Recommended minimum approach speed. (Something like 1.3 Vs at MTOW and
> landing configuration or some such.) Drop below this at the checkride, and
> you are invited to show up for a second try.
>
> Stefan

Never seen a yellow marker on the ASI. Is it part of the instrument or
stuck on the outside. What flap setting is it for?

Mike
MU-2

[Mike Rapoport]

"Stefan" > wrote in message
...
> Milen Lazarov wrote:
>
>> Jay Honeck wrote:
>>
>>> As I turned from base to final, the unexpectedly strong wind had me bent
>>> out of shape pretty good, but I managed to wrestle the runway back into
>>> alignment without entering the coffin-corner of cross controlling.
>
>> What is a coffin-corner and how does one get into it in the pattern?
>
> Jay frivolously used that well defined term completely wrong, presumably
> just because it sounds good. (A tactic which some journalists use, too,
> especially when they write about aviation...) You never get into the
> coffin corner at pattern altitude.
>
> The stall speed is constant with indicated airspeed, while Vne is constant
> with true airspeed (acually, it decreases somewhat at high altitudes). So
> there is a point, at very high altitudes, where Vs meets Vne. This point
> is called the coffin corner, because you can't escape from it (except by
> descending): You can't slow down (stall) nor accelerate (Vne).
>
> Stefan

I always thought that the "coffin corner" was where stall speed met the Mach
limit. I didn't think that it even applied to non-jet aircraft.

Mike
MU-2

[Morgans]

"Mike Rapoport" > wrote
>
> I always thought that the "coffin corner" was where stall speed met the
Mach
> limit. I didn't think that it even applied to non-jet aircraft.
>
> Mike

No, I think the post above yours got it pretty much right..Vne is
significant, in that it demonstrates itself by nasty things like flutter, or
control reversal. Pull back on the stick to maneuver, or slow down, and
stall, or at least buffet like hell.

It is true, however, that it is pretty tough for a non jet aircraft to get
to the coffin corner. The Exxon tiger (can't think of the guy's name) that
has been trying to get the piston altitude record, has said that he is
really close to getting into coffin corner.
--
Jim in NC

[Jim]

On Tue, 8 Mar 2005 17:24:46 -0500, "Morgans" >
wrote:

>
>"Mike Rapoport" > wrote
>>
>> I always thought that the "coffin corner" was where stall speed met the
>Mach
>> limit. I didn't think that it even applied to non-jet aircraft.
>>
>> Mike
>
>No, I think the post above yours got it pretty much right..Vne is
>significant, in that it demonstrates itself by nasty things like flutter, or
>control reversal. Pull back on the stick to maneuver, or slow down, and
>stall, or at least buffet like hell.
>
> It is true, however, that it is pretty tough for a non jet aircraft to get
>to the coffin corner. The Exxon tiger (can't think of the guy's name) that
>has been trying to get the piston altitude record, has said that he is
>really close to getting into coffin corner.

Another "coffin corner" I have heard discussed is the convergence of
Vne and Vs as altitude increases. I think it went something like
this:

1. Vne is a TAS, so its IAS decreases with increasing altitude.
Vs is an IAS, so as IAS, it remains the same with increasing
altitude.
Therefore, Vne, in IAS converges with Vs in IAS as
altitude increases.
2. Seen the other way, the TAS of Vs increases with altitude,
converging with the fixed TAS of Vne.

Or something like that I guess.

[Bob Moore]

"Morgans" wrote
> No, I think the post above yours got it pretty much right..Vne is
> significant, in that it demonstrates itself by nasty things like
> flutter, or control reversal.

Nope! Mike got it right.


"Jim" wrote
>Another "coffin corner" I have heard discussed is the convergence of
>Vne and Vs as altitude increases.

Nope! Mike got it right.

Coffin corner
From Wikipedia
Coffin corner is a dangerous portion of the flight envelope that must be
carefully approached by high altitude high subsonic speed aircraft, such
as the Lockheed U-2 aircraft.
Mach Limit
A subsonic aircraft must not exceed its Mach limit, some fraction of the
speed of sound near, but not at 1.0. At the low air densities encountered
at high altitude the speed of sound is lower. Exceeding the Mach limit
can cause loss of control and/or structural failure.
Stall Limit
At high altitudes the low density air is less capable of supporting the
aircraft and so the stall speed increases (as expressed in true air
speed).
The Corner
At some limiting altitude these speeds converge, and the aircraft cannot
be flown, as a slight pitch down will cause the Mach limit to be exceeded
while a slight pitch up will cause an aircraft stall with a subsequent
pitch down.


I've been to "coffin corner" in a Navy T2-V and very near to it in a
Boeing 707 and neither time was I close to Vne..Critical Mach
Number..yes, but not Vne.


Bob Moore
ATP B-707 B-727

[Morgans]

"Bob Moore" > wrote

> Nope! Mike got it right.

Ok, so what is the thing that Bruce , in the Exxon Tiger experienced? I'm
quite sure that is what he called it, and could look back in the Magazines,
to the interview.

Some of my descriptions may have been off, but those were his words.

I have no doubt that what you described is accurate, but am also as
confident that there are other ways, in other aircraft, to get there.
Possible?
--
Jim in NC

[Mike Rapoport]

"Morgans" > wrote in message
...
>
> "Mike Rapoport" > wrote
>>
>> I always thought that the "coffin corner" was where stall speed met the
> Mach
>> limit. I didn't think that it even applied to non-jet aircraft.
>>
>> Mike
>
> No, I think the post above yours got it pretty much right..Vne is
> significant, in that it demonstrates itself by nasty things like flutter,
> or
> control reversal. Pull back on the stick to maneuver, or slow down, and
> stall, or at least buffet like hell.
>
> It is true, however, that it is pretty tough for a non jet aircraft to get
> to the coffin corner. The Exxon tiger (can't think of the guy's name)
> that
> has been trying to get the piston altitude record, has said that he is
> really close to getting into coffin corner.
> --
> Jim in NC
>


I've never heard of Vne being related to TAS, only IAS. It makes no sense
to me. Could you provide a reference?

Mike
MU-2

[Jim]

On Wed, 09 Mar 2005 14:58:38 GMT, "Mike Rapoport"
> wrote:

>
>"Morgans" > wrote in message
...
>>
>> "Mike Rapoport" > wrote
>>>
>>> I always thought that the "coffin corner" was where stall speed met the
>> Mach
>>> limit. I didn't think that it even applied to non-jet aircraft.
>>>
>>> Mike
>>
>> No, I think the post above yours got it pretty much right..Vne is
>> significant, in that it demonstrates itself by nasty things like flutter,
>> or
>> control reversal. Pull back on the stick to maneuver, or slow down, and
>> stall, or at least buffet like hell.
>>
>> It is true, however, that it is pretty tough for a non jet aircraft to get
>> to the coffin corner. The Exxon tiger (can't think of the guy's name)
>> that
>> has been trying to get the piston altitude record, has said that he is
>> really close to getting into coffin corner.
>> --
>> Jim in NC
>>
>
>
>I've never heard of Vne being related to TAS, only IAS. It makes no sense
>to me. Could you provide a reference?
>
>Mike
>MU-2
>
>

I'm not sure this is addressed to me, but just in case it is:

I guess the notion about Vne as a TAS is that Vne may be specified for
a given aircraft as an airspeed that depends on altitude. I guess it
could as easily be specified as an IAS at sea level and gross weight,
with a written notice to the pilot that Vne would then be at a lower
IAS as altitude increases. Does this make any sense?

[Mike Rapoport]

"Jim" > wrote in message
...
> On Wed, 09 Mar 2005 14:58:38 GMT, "Mike Rapoport"
> > wrote:
>
>>
>>"Morgans" > wrote in message
...
>>>
>>> "Mike Rapoport" > wrote
>>>>
>>>> I always thought that the "coffin corner" was where stall speed met the
>>> Mach
>>>> limit. I didn't think that it even applied to non-jet aircraft.
>>>>
>>>> Mike
>>>
>>> No, I think the post above yours got it pretty much right..Vne is
>>> significant, in that it demonstrates itself by nasty things like
>>> flutter,
>>> or
>>> control reversal. Pull back on the stick to maneuver, or slow down, and
>>> stall, or at least buffet like hell.
>>>
>>> It is true, however, that it is pretty tough for a non jet aircraft to
>>> get
>>> to the coffin corner. The Exxon tiger (can't think of the guy's name)
>>> that
>>> has been trying to get the piston altitude record, has said that he is
>>> really close to getting into coffin corner.
>>> --
>>> Jim in NC
>>>
>>
>>
>>I've never heard of Vne being related to TAS, only IAS. It makes no sense
>>to me. Could you provide a reference?
>>
>>Mike
>>MU-2
>>
>>
>
> I'm not sure this is addressed to me, but just in case it is:
>
> I guess the notion about Vne as a TAS is that Vne may be specified for
> a given aircraft as an airspeed that depends on altitude. I guess it
> could as easily be specified as an IAS at sea level and gross weight,
> with a written notice to the pilot that Vne would then be at a lower
> IAS as altitude increases. Does this make any sense?

Yes and no. What you are describing is Mmo which is the limiting Mach
number. It is not Vne. Vne is a fixed mark on the airspeed indicator and,
as such, doesn't move. Mmo is a red "barber pole" on the airspeed indicator
which moves down as altitude increases.

Mike
MU-2

[Jim]

On Wed, 09 Mar 2005 16:29:46 GMT, "Mike Rapoport"
> wrote:

>
>"Jim" > wrote in message
...
>> On Wed, 09 Mar 2005 14:58:38 GMT, "Mike Rapoport"
>> > wrote:
>>
>>>
>>>"Morgans" > wrote in message
...
>>>>
>>>> "Mike Rapoport" > wrote
>>>>>
>>>>> I always thought that the "coffin corner" was where stall speed met the
>>>> Mach
>>>>> limit. I didn't think that it even applied to non-jet aircraft.
>>>>>
>>>>> Mike
>>>>
>>>> No, I think the post above yours got it pretty much right..Vne is
>>>> significant, in that it demonstrates itself by nasty things like
>>>> flutter,
>>>> or
>>>> control reversal. Pull back on the stick to maneuver, or slow down, and
>>>> stall, or at least buffet like hell.
>>>>
>>>> It is true, however, that it is pretty tough for a non jet aircraft to
>>>> get
>>>> to the coffin corner. The Exxon tiger (can't think of the guy's name)
>>>> that
>>>> has been trying to get the piston altitude record, has said that he is
>>>> really close to getting into coffin corner.
>>>> --
>>>> Jim in NC
>>>>
>>>
>>>
>>>I've never heard of Vne being related to TAS, only IAS. It makes no sense
>>>to me. Could you provide a reference?
>>>
>>>Mike
>>>MU-2
>>>
>>>
>>
>> I'm not sure this is addressed to me, but just in case it is:
>>
>> I guess the notion about Vne as a TAS is that Vne may be specified for
>> a given aircraft as an airspeed that depends on altitude. I guess it
>> could as easily be specified as an IAS at sea level and gross weight,
>> with a written notice to the pilot that Vne would then be at a lower
>> IAS as altitude increases. Does this make any sense?
>
>Yes and no. What you are describing is Mmo which is the limiting Mach
>number. It is not Vne. Vne is a fixed mark on the airspeed indicator and,
>as such, doesn't move. Mmo is a red "barber pole" on the airspeed indicator
>which moves down as altitude increases.
>
>Mike
>MU-2
>

Well, yes Vne is marked on the ASI, and as such a mark it does not
move.

On the other hand, for several of the gliders I fly the manufacturers
make a point in the POH of directing the pilot to reduce the marked
Vne as flight altitude increases.

So I take the marked Vne as relating to sea level and adjust it
downward at increasing altitudes.

[Mike Rapoport]

"T o d d P a t t i s t" > wrote in message
...
> "Mike Rapoport" > wrote:
>
>>>>I've never heard of Vne being related to TAS, only IAS. It makes no
>>>>sense
>>>>to me. Could you provide a reference?
>>
>>Vne is a fixed mark on the airspeed indicator and,
>>as such, doesn't move.
>
> Despite the Vne mark on the altimeter, it definitely is not
> a fixed IAS (or CAS) number. Nor is it always a fixed TAS
> number. It is the number defined by the manufacturer that
> is usually found in the flight manual. My sailplane has a
> Vne that drops with altitude, and while it's closer to a
> fixed TAS than IAS, it's not exactly either.
>
> A fixed TAS makes sense because it is often flutter that
> sets the Vne limit, and flutter is a timing related issue
> that relates to TAS more closely than IAS.
>
> "It is possible to fly without motors, but not without knowledge and
> skill."
> Wilbur Wright

So what is the mark on the airspeed indicator supposed to mean then? I have
never seen anything in any of the flight manuals that I have (four)
referring to Vne going down with altitude. I am not disputing that it does
but I am mystified as to why it isn't better explained in flight manuals.
Similiarly, Vmo is given as a single IAS number. In the MU-2 Vmo is 250kts
IAS at any altitude up to about 22,000' where the Mach limit takes over.
This is a large range of TAS. Is it perhaps actually related to Mmo rather
than Vne as gliders don't have airspeed indicators with barber poles? Can
you give some examples wth real numbers and altitudes?

Mike
MU-2

[Morgans]

"Mike Rapoport" > wrote
>
> I've never heard of Vne being related to TAS, only IAS. It makes no sense
> to me. Could you provide a reference?
>
> Mike

True. My mistake.
--
Jim in NC

[Jim]

On Wed, 09 Mar 2005 21:52:58 GMT, "Mike Rapoport"
> wrote:

>
>"T o d d P a t t i s t" > wrote in message
...
>> "Mike Rapoport" > wrote:
>>
>>>>>I've never heard of Vne being related to TAS, only IAS. It makes no
>>>>>sense
>>>>>to me. Could you provide a reference?
>>>
>>>Vne is a fixed mark on the airspeed indicator and,
>>>as such, doesn't move.
>>
>> Despite the Vne mark on the altimeter, it definitely is not
>> a fixed IAS (or CAS) number. Nor is it always a fixed TAS
>> number. It is the number defined by the manufacturer that
>> is usually found in the flight manual. My sailplane has a
>> Vne that drops with altitude, and while it's closer to a
>> fixed TAS than IAS, it's not exactly either.
>>
>> A fixed TAS makes sense because it is often flutter that
>> sets the Vne limit, and flutter is a timing related issue
>> that relates to TAS more closely than IAS.
>>
>> "It is possible to fly without motors, but not without knowledge and
>> skill."
>> Wilbur Wright
>
>So what is the mark on the airspeed indicator supposed to mean then? I have
>never seen anything in any of the flight manuals that I have (four)
>referring to Vne going down with altitude. I am not disputing that it does
>but I am mystified as to why it isn't better explained in flight manuals.
>Similiarly, Vmo is given as a single IAS number. In the MU-2 Vmo is 250kts
>IAS at any altitude up to about 22,000' where the Mach limit takes over.
>This is a large range of TAS. Is it perhaps actually related to Mmo rather
>than Vne as gliders don't have airspeed indicators with barber poles? Can
>you give some examples wth real numbers and altitudes?
>
>Mike
>MU-2
>

It is confusing. Because the high end of the red arc on the ASI is
described as Vne, it certainly would suggest Vne is an IAS and can
be flown as such. But this is not what many glider POH instructions
state.

I don't have a POH here at work. I'll try to remember to give you an
example from one of the ones I have.

[Jim]

On Wed, 09 Mar 2005 21:52:58 GMT, "Mike Rapoport"
> wrote:

>
>"T o d d P a t t i s t" > wrote in message
...
>> "Mike Rapoport" > wrote:
>>
>>>>>I've never heard of Vne being related to TAS, only IAS. It makes no
>>>>>sense
>>>>>to me. Could you provide a reference?
>>>
>>>Vne is a fixed mark on the airspeed indicator and,
>>>as such, doesn't move.
>>
>> Despite the Vne mark on the altimeter, it definitely is not
>> a fixed IAS (or CAS) number. Nor is it always a fixed TAS
>> number. It is the number defined by the manufacturer that
>> is usually found in the flight manual. My sailplane has a
>> Vne that drops with altitude, and while it's closer to a
>> fixed TAS than IAS, it's not exactly either.
>>
>> A fixed TAS makes sense because it is often flutter that
>> sets the Vne limit, and flutter is a timing related issue
>> that relates to TAS more closely than IAS.
>>
>> "It is possible to fly without motors, but not without knowledge and
>> skill."
>> Wilbur Wright
>
>So what is the mark on the airspeed indicator supposed to mean then? I have
>never seen anything in any of the flight manuals that I have (four)
>referring to Vne going down with altitude. I am not disputing that it does
>but I am mystified as to why it isn't better explained in flight manuals.
>Similiarly, Vmo is given as a single IAS number. In the MU-2 Vmo is 250kts
>IAS at any altitude up to about 22,000' where the Mach limit takes over.
>This is a large range of TAS. Is it perhaps actually related to Mmo rather
>than Vne as gliders don't have airspeed indicators with barber poles? Can
>you give some examples wth real numbers and altitudes?
>
>Mike
>MU-2
>

Here is the information from the Flight Manual for the DG-500 glider.

Section 4.5.9 Flight at high altitude and at low temperatures:

...

2. Attention must be paid to the fact that at higher
altitudes the true airspeed is greater than the
indicated airspeed.
The max. speed Vne is reduced. See the
following table:

...

Altitude in ft. 0-6600 10000 13000 16000 20000
Vne IAS kts. 146 138 131 124
117

Hope this helps.

[Mike Rapoport]

"Jim" > wrote in message
...
> On Wed, 09 Mar 2005 21:52:58 GMT, "Mike Rapoport"
> > wrote:
>
>>
>>"T o d d P a t t i s t" > wrote in message
...
>>> "Mike Rapoport" > wrote:
>>>
>>>>>>I've never heard of Vne being related to TAS, only IAS. It makes no
>>>>>>sense
>>>>>>to me. Could you provide a reference?
>>>>
>>>>Vne is a fixed mark on the airspeed indicator and,
>>>>as such, doesn't move.
>>>
>>> Despite the Vne mark on the altimeter, it definitely is not
>>> a fixed IAS (or CAS) number. Nor is it always a fixed TAS
>>> number. It is the number defined by the manufacturer that
>>> is usually found in the flight manual. My sailplane has a
>>> Vne that drops with altitude, and while it's closer to a
>>> fixed TAS than IAS, it's not exactly either.
>>>
>>> A fixed TAS makes sense because it is often flutter that
>>> sets the Vne limit, and flutter is a timing related issue
>>> that relates to TAS more closely than IAS.
>>>
>>> "It is possible to fly without motors, but not without knowledge and
>>> skill."
>>> Wilbur Wright
>>
>>So what is the mark on the airspeed indicator supposed to mean then? I
>>have
>>never seen anything in any of the flight manuals that I have (four)
>>referring to Vne going down with altitude. I am not disputing that it
>>does
>>but I am mystified as to why it isn't better explained in flight manuals.
>>Similiarly, Vmo is given as a single IAS number. In the MU-2 Vmo is
>>250kts
>>IAS at any altitude up to about 22,000' where the Mach limit takes over.
>>This is a large range of TAS. Is it perhaps actually related to Mmo
>>rather
>>than Vne as gliders don't have airspeed indicators with barber poles? Can
>>you give some examples wth real numbers and altitudes?
>>
>>Mike
>>MU-2
>>
>
> Here is the information from the Flight Manual for the DG-500 glider.
>
> Section 4.5.9 Flight at high altitude and at low temperatures:
>
> ...
>
> 2. Attention must be paid to the fact that at higher
> altitudes the true airspeed is greater than the
> indicated airspeed.
> The max. speed Vne is reduced. See the
> following table:
>
> ...
>
> Altitude in ft. 0-6600 10000 13000 16000 20000
> Vne IAS kts. 146 138 131 124
> 117
>
> Hope this helps.
>
>

Thanks, it does. The question of what the red mark on powered airplanes
means remains. Is it Vne at the aircraft's ceiling? If it is Vne at sea
level then there should be some language in the flight manual warning of
this.

The reference to low temperatures is also interesting. Is the strength of
the glider's resin reduced at low temperatures?

Mike
MU-2

[Bob Moore]

"Mike Rapoport" wrote
> Thanks, it does. The question of what the red mark on powered
> airplanes means remains. Is it Vne at the aircraft's ceiling? If it
> is Vne at sea level then there should be some language in the flight
> manual warning of this.

Mike... this is from 23.1545

(c) If VNE or VNO vary with altitude, there must be means to indicate to
the pilot the appropriate limitations throughout the operating altitude
range.

(d) Paragraphs (b)(1) through (b)(3) and paragraph (c) of this section do
not apply to aircraft for which a maximum operating speed VMO/MMO is
established under §23.1505(c). For those aircraft there must either be a
maximum allowable airspeed indication showing the variation of VMO/MMO with
altitude or compressibility limitations (as appropriate), or a radial red
line marking for VMO/MMO must be made at lowest value of VMO/MMO
established for any altitude up to the maximum operating altitude for the
airplane.

Bob Moore

[Jim Burns]

Mike,
I don't know if it will help, but you may find some guidence in part 23.1505
and 23.335. I started to read through it and the only thing I ended up with
was a headache.

Jim Burns
(the other Jim)

"Mike Rapoport" > wrote in message
ink.net...
>
> "Jim" > wrote in message
>
> Thanks, it does. The question of what the red mark on powered airplanes
> means remains. Is it Vne at the aircraft's ceiling? If it is Vne at sea
> level then there should be some language in the flight manual warning of
> this.
>
> The reference to low temperatures is also interesting. Is the strength of
> the glider's resin reduced at low temperatures?
>
> Mike
> MU-2
>
>

[Jim]

On Thu, 10 Mar 2005 15:22:53 GMT, "Mike Rapoport"
> wrote:

>
>"Jim" > wrote in message
...
>> On Wed, 09 Mar 2005 21:52:58 GMT, "Mike Rapoport"
>> > wrote:
>>
>>>
>>>"T o d d P a t t i s t" > wrote in message
...
>>>> "Mike Rapoport" > wrote:
>>>>
>>>>>>>I've never heard of Vne being related to TAS, only IAS. It makes no
>>>>>>>sense
>>>>>>>to me. Could you provide a reference?
>>>>>
>>>>>Vne is a fixed mark on the airspeed indicator and,
>>>>>as such, doesn't move.
>>>>
>>>> Despite the Vne mark on the altimeter, it definitely is not
>>>> a fixed IAS (or CAS) number. Nor is it always a fixed TAS
>>>> number. It is the number defined by the manufacturer that
>>>> is usually found in the flight manual. My sailplane has a
>>>> Vne that drops with altitude, and while it's closer to a
>>>> fixed TAS than IAS, it's not exactly either.
>>>>
>>>> A fixed TAS makes sense because it is often flutter that
>>>> sets the Vne limit, and flutter is a timing related issue
>>>> that relates to TAS more closely than IAS.
>>>>
>>>> "It is possible to fly without motors, but not without knowledge and
>>>> skill."
>>>> Wilbur Wright
>>>
>>>So what is the mark on the airspeed indicator supposed to mean then? I
>>>have
>>>never seen anything in any of the flight manuals that I have (four)
>>>referring to Vne going down with altitude. I am not disputing that it
>>>does
>>>but I am mystified as to why it isn't better explained in flight manuals.
>>>Similiarly, Vmo is given as a single IAS number. In the MU-2 Vmo is
>>>250kts
>>>IAS at any altitude up to about 22,000' where the Mach limit takes over.
>>>This is a large range of TAS. Is it perhaps actually related to Mmo
>>>rather
>>>than Vne as gliders don't have airspeed indicators with barber poles? Can
>>>you give some examples wth real numbers and altitudes?
>>>
>>>Mike
>>>MU-2
>>>
>>
>> Here is the information from the Flight Manual for the DG-500 glider.
>>
>> Section 4.5.9 Flight at high altitude and at low temperatures:
>>
>> ...
>>
>> 2. Attention must be paid to the fact that at higher
>> altitudes the true airspeed is greater than the
>> indicated airspeed.
>> The max. speed Vne is reduced. See the
>> following table:
>>
>> ...
>>
>> Altitude in ft. 0-6600 10000 13000 16000 20000
>> Vne IAS kts. 146 138 131 124
>> 117
>>
>> Hope this helps.
>>
>>
>
>Thanks, it does. The question of what the red mark on powered airplanes
>means remains. Is it Vne at the aircraft's ceiling? If it is Vne at sea
>level then there should be some language in the flight manual warning of
>this.
>
>The reference to low temperatures is also interesting. Is the strength of
>the glider's resin reduced at low temperatures?
>
>Mike
>MU-2
>

Here is the text relating to low tempertures from the flight manual:

With temperatures below 0 degrees C (32 F), for instance
when wave flying or flying in winter, it is possible that the
control circuits could become stiffer. Special care
should be taken to ensure that there is no moisture on
any section of the control circuits to minimize the
possibility of freeze up.
It could be advantageous to apply vaseline along
all the edges of the airbrake cover plates to
minimize the possibility of freezing closed.

Also, item 1, which I did not include in my previous reply states:

1. At termperatures below -20 degrees C ( -4F) there
is the risk of cracking the gelcoat.

I don't think the glider's structure would really suffer damage
though.

[Mike Rapoport]

OK, this makes sense. It is simpler to position the red mark for the most
conservative conditions than to have a varying Vne. In gliders, often used
for racing, it makes sense to provide the pilot with the actual Vne which
varies with altitude so that they can extract maximium performance.

Mike
MU-2



"T o d d P a t t i s t" > wrote in message
...
> "Mike Rapoport" > wrote:
>[i]
>>>>Vne is a fixed mark on the airspeed indicator and,
>>>>as such, doesn't move.
>>>
>>> Despite the Vne mark on the altimeter, it definitely is not
>>> a fixed IAS (or CAS) number. Nor is it always a fixed TAS
>>> number. It is the number defined by the manufacturer that
>>> is usually found in the flight manual.
>>> Wilbur Wright
>>
>>So what is the mark on the airspeed indicator supposed to mean then?
>
> Good question. Here's the rule:
>
> FAA Federal Aviation Regulations (FARS, 14 CFR)
> 23.1545 - Airspeed indicator
>
> (a) Each airspeed indicator must be marked as specified
> ...
>
> (c) If VNE or VNO vary with altitude, there must be means to
> indicate to the pilot the appropriate limitations throughout
> the operating altitude range.
>
> I suspect the compliance method used is to put the limits in
> the handbook and put a placard in the aircraft. That's how
> it's done in mine.
>
> Here's the rule when VMO/MMO applies and Vne does not:
>
> (d) ... For those aircraft there must either be a maximum
> allowable airspeed indication showing the variation of
> VMO/MMO with altitude or compressibility limitations (as
> appropriate), or a radial red line marking for VMO/MMO must
> be made at lowest value of VMO/MMO established for any
> altitude up to the maximum operating altitude for the
> airplane.
>
> My Vne red line is the speed at sea level, and it begins to
> drop above 10,000' per the placard and flight manual.
>
>> I have
>>never seen anything in any of the flight manuals that I have (four)
>>referring to Vne going down with altitude. I am not disputing that it
>>does
>>but I am mystified as to why it isn't better explained in flight manuals.
>
> If it's not placarded and doesn't appear in the flight
> manual, you can assume the red line is correct up to maximum
> operating altitude. Of course, you can fly airplanes above
> service ceiling with some help from nature (wave lift comes
> to mind), just as you can fly a glider, so you still want to
> be aware of the common altitude dependency of Vne. You
> can't really assume anything about Vne except when flying
> within the limits.
>
>
>
> "It is possible to fly without motors, but not without knowledge and
> skill."
> Wilbur Wright

[Mike Rapoport]

"Bob Moore" > wrote in message
. 121...
> "Mike Rapoport" wrote
>> Thanks, it does. The question of what the red mark on powered
>> airplanes means remains. Is it Vne at the aircraft's ceiling? If it
>> is Vne at sea level then there should be some language in the flight
>> manual warning of this.
>
> Mike... this is from 23.1545
>
> (c) If VNE or VNO vary with altitude, there must be means to indicate to
> the pilot the appropriate limitations throughout the operating altitude
> range.
>
> (d) Paragraphs (b)(1) through (b)(3) and paragraph (c) of this section do
> not apply to aircraft for which a maximum operating speed VMO/MMO is
> established under §23.1505(c). For those aircraft there must either be a
> maximum allowable airspeed indication showing the variation of VMO/MMO
> with
> altitude or compressibility limitations (as appropriate), or a radial red
> line marking for VMO/MMO must be made at lowest value of VMO/MMO
> established for any altitude up to the maximum operating altitude for the
> airplane.
>
> Bob Moore

Thanks for the reference. It makes sense now.

Mike
MU-2

[Mike Rapoport]

Thanks Jim. The gliders used for wave soaring at Minden all had cracked gel
coats on the underside of the wing and some had cracking on the upper
surface too.

Mike
MU-2

"Jim" > wrote in message
...
> On Thu, 10 Mar 2005 15:22:53 GMT, "Mike Rapoport"
> > wrote:
>
>>
>>"Jim" > wrote in message
...
>>> On Wed, 09 Mar 2005 21:52:58 GMT, "Mike Rapoport"
>>> > wrote:
>>>
>>>>
>>>>"T o d d P a t t i s t" > wrote in message
...
>>>>> "Mike Rapoport" > wrote:
>>>>>
>>>>>>>>I've never heard of Vne being related to TAS, only IAS. It makes no
>>>>>>>>sense
>>>>>>>>to me. Could you provide a reference?
>>>>>>
>>>>>>Vne is a fixed mark on the airspeed indicator and,
>>>>>>as such, doesn't move.
>>>>>
>>>>> Despite the Vne mark on the altimeter, it definitely is not
>>>>> a fixed IAS (or CAS) number. Nor is it always a fixed TAS
>>>>> number. It is the number defined by the manufacturer that
>>>>> is usually found in the flight manual. My sailplane has a
>>>>> Vne that drops with altitude, and while it's closer to a
>>>>> fixed TAS than IAS, it's not exactly either.
>>>>>
>>>>> A fixed TAS makes sense because it is often flutter that
>>>>> sets the Vne limit, and flutter is a timing related issue
>>>>> that relates to TAS more closely than IAS.
>>>>>
>>>>> "It is possible to fly without motors, but not without knowledge and
>>>>> skill."
>>>>> Wilbur Wright
>>>>
>>>>So what is the mark on the airspeed indicator supposed to mean then? I
>>>>have
>>>>never seen anything in any of the flight manuals that I have (four)
>>>>referring to Vne going down with altitude. I am not disputing that it
>>>>does
>>>>but I am mystified as to why it isn't better explained in flight
>>>>manuals.
>>>>Similiarly, Vmo is given as a single IAS number. In the MU-2 Vmo is
>>>>250kts
>>>>IAS at any altitude up to about 22,000' where the Mach limit takes over.
>>>>This is a large range of TAS. Is it perhaps actually related to Mmo
>>>>rather
>>>>than Vne as gliders don't have airspeed indicators with barber poles?
>>>>Can
>>>>you give some examples wth real numbers and altitudes?
>>>>
>>>>Mike
>>>>MU-2
>>>>
>>>
>>> Here is the information from the Flight Manual for the DG-500 glider.
>>>
>>> Section 4.5.9 Flight at high altitude and at low temperatures:
>>>
>>> ...
>>>
>>> 2. Attention must be paid to the fact that at higher
>>> altitudes the true airspeed is greater than the
>>> indicated airspeed.
>>> The max. speed Vne is reduced. See the
>>> following table:
>>>
>>> ...
>>>
>>> Altitude in ft. 0-6600 10000 13000 16000 20000
>>> Vne IAS kts. 146 138 131 124
>>> 117
>>>
>>> Hope this helps.
>>>
>>>
>>
>>Thanks, it does. The question of what the red mark on powered airplanes
>>means remains. Is it Vne at the aircraft's ceiling? If it is Vne at sea
>>level then there should be some language in the flight manual warning of
>>this.
>>
>>The reference to low temperatures is also interesting. Is the strength of
>>the glider's resin reduced at low temperatures?
>>
>>Mike
>>MU-2
>>
>
> Here is the text relating to low tempertures from the flight manual:
>
> With temperatures below 0 degrees C (32 F), for instance
> when wave flying or flying in winter, it is possible that the
> control circuits could become stiffer. Special care
> should be taken to ensure that there is no moisture on
> any section of the control circuits to minimize the
> possibility of freeze up.
> It could be advantageous to apply vaseline along
> all the edges of the airbrake cover plates to
> minimize the possibility of freezing closed.
>
> Also, item 1, which I did not include in my previous reply states:
>
> 1. At termperatures below -20 degrees C ( -4F) there
> is the risk of cracking the gelcoat.
>
> I don't think the glider's structure would really suffer damage
> though.
>
>