GPS instead of turn and bank

[Danny Deger]

I am thinking about buying a 1946 Taylorcraft that has NO gyros at all on
the panel. I really want at least a turn and bank so I want die if I loose
reference to the horizon for any reason. I have been told that the heading
information from a GPS is good enough to do the function of a turn and bank
and allow emergency operations without having a visual horizon reference.
Is this correct?

Danny Deger

[Tony]

How are you going to determine bank with a GPS?

On Feb 4, 5:24 pm, "Danny Deger" > wrote:
> I am thinking about buying a 1946 Taylorcraft that has NO gyros at all on
> the panel. I really want at least a turn and bank so I want die if I loose
> reference to the horizon for any reason. I have been told that the heading
> information from a GPS is good enough to do the function of a turn and bank
> and allow emergency operations without having a visual horizon reference.
> Is this correct?
>
> Danny Deger

[Neil Gould]

Recently, Danny Deger > posted:

> I am thinking about buying a 1946 Taylorcraft that has NO gyros at
> all on the panel. I really want at least a turn and bank so I want
> die if I loose reference to the horizon for any reason. I have been
> told that the heading information from a GPS is good enough to do the
> function of a turn and bank and allow emergency operations without
> having a visual horizon reference. Is this correct?
>
Aviation-oriented GPS units with moving map displays often have an HSI
mode, so you may be able to eventually detect turn, but not bank. I would
think it unwise to rely on that for orientation.

Neil

[Mxsmanic]

Danny Deger writes:

> I am thinking about buying a 1946 Taylorcraft that has NO gyros at all on
> the panel. I really want at least a turn and bank so I want die if I loose
> reference to the horizon for any reason. I have been told that the heading
> information from a GPS is good enough to do the function of a turn and bank
> and allow emergency operations without having a visual horizon reference.
> Is this correct?

A GPS can only determine your track over the ground, which may not be
your heading. If there is no wind, both are the same, but if there is
any wind, your heading could be significantly different from your
ground track.

GPS cannot determine your bank angle. In theory a GPS could determine
if you appear to be making a standard turn, if there is no wind. I
don't know of any actual GPS units that do this (?), and it becomes
complicated if there is any wind.

Remember, GPS units can only determine your location in space
(longitude and latitude and, with somewhat less precision, altitude).
Apart from that basic information, all other information they provide
is derived from observing the changes in your location over time.
They cannot provide any information that cannot be calculated from
this data. They do not know the actual attitude or heading of the
aircraft: a 45-degree bank and a 30-degree downward pitch angle look
exactly the same as level flight to a GPS.

--
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[Jim Macklin]

Maybe, but you'd be better off with both.

But why would you loose reference to the horizon? Even a
T-Craft can flay away from clouds faster than the wind
blows.


"Danny Deger" > wrote in message
...
|I am thinking about buying a 1946 Taylorcraft that has NO
gyros at all on
| the panel. I really want at least a turn and bank so I
want die if I loose
| reference to the horizon for any reason. I have been told
that the heading
| information from a GPS is good enough to do the function
of a turn and bank
| and allow emergency operations without having a visual
horizon reference.
| Is this correct?
|
| Danny Deger
|
|

[Ron Natalie]

Tony wrote:
> How are you going to determine bank with a GPS?
>
Indirectly. The same way you do with a needle-ball gauge.
If you ain't turning, you ain't banked. It's actually
a whole lot easier to track straight ahead with my GNS480
than with the turn coordinator when flying partial panel.

[Ron Natalie]

Mxsmanic wrote:

> A GPS can only determine your track over the ground, which may not be
> your heading.

This is the only thing that you said in your three whole stupid
ass paragraphs that was correct or the least bit relevent.

Unless you actually learn something about flying IFR in reality
rather than ****ing your life away in front of flight simulator
you'll never have an understanding of flight.

By the way, if you got your lard ass out of your chair and got
some excercise, you wouldn't overgross the training ships you
might be able to fly.

[vincent p. norris]

>I am thinking about buying a 1946 Taylorcraft that has NO gyros at all on
>the panel. I really want at least a turn and bank so I want die if I loose
>reference to the horizon for any reason. I have been told that the heading
>information from a GPS is good enough to do the function of a turn and bank
>and allow emergency operations without having a visual horizon reference.
>Is this correct?

You can obtain the BEST answer to yoyur question by going up and
trying it out.

I've shot three or four simulated "ILS" approaches under the hood,
using only a Garmin 396 plus the aircraft's airspeed and altitude
indicators. The 396 has an imitation turn coordinator that is jerky
and has a delay but it works well enough to keep you right-side up and
get you to the airport.

I have NOT tried using it to recover from unexpected "unusual
attitudes," which is another matter.

vince norris

[J. Severyn]

"Tony" > wrote in message
ps.com...
> How are you going to determine bank with a GPS?
>
> On Feb 4, 5:24 pm, "Danny Deger" > wrote:
>> I am thinking about buying a 1946 Taylorcraft that has NO gyros at all on
>> the panel. I really want at least a turn and bank so I want die if I
>> loose
>> reference to the horizon for any reason. I have been told that the
>> heading
>> information from a GPS is good enough to do the function of a turn and
>> bank
>> and allow emergency operations without having a visual horizon reference.
>> Is this correct?
>>
>> Danny Deger
>
>
Actually there are specialized GPS units that can determine attitude and
they have been around for at least 10-12 years. Google the "Trimble TANS
Vector" and you will see one of the earlier units.
http://trl.trimble.com/docushare/dsweb/Get/Document-19330/20997-00-C.pdf
They operate by using at least 3 antennae (usually four antennae) and
directly determine roll, pitch and yaw using carrier phase differences from
the GPS satellites. Of course this is not the way the portable units derive
the HSI info.

The carrier phase units are commonly used as either primary or secondary
IMUs (with some other 3 axis gyro like a laser gyro) in high-end UAVs or
other military type hardware.

Regards,
John Severyn

[Kyle Boatright]

"Danny Deger" > wrote in message
...
>I am thinking about buying a 1946 Taylorcraft that has NO gyros at all on
>the panel. I really want at least a turn and bank so I want die if I loose
>reference to the horizon for any reason. I have been told that the heading
>information from a GPS is good enough to do the function of a turn and bank
>and allow emergency operations without having a visual horizon reference.
>Is this correct?
>
> Danny Deger

The problem is that your GPS can't tell you how much to correct to bring the
ship back to wings level. Also, GPS refresh rates and software may not work
fast enough to give you an idea of what your turn rate is *right now*. Not
that the GPS idea couldn't work, but I don't see it as a reliable method,
which is what you want when your life is on the line.

KB

[Dave[_3_]]

Umm... OK.

So may I ask what was wrong with his other two paragraphs?

Dave



On Sun, 04 Feb 2007 19:09:26 -0500, Ron Natalie >
wrote:

>Mxsmanic wrote:
>
>> A GPS can only determine your track over the ground, which may not be
>> your heading.
>
>This is the only thing that you said in your three whole stupid
>ass paragraphs that was correct or the least bit relevent.
>
>Unless you actually learn something about flying IFR in reality
>rather than ****ing your life away in front of flight simulator
>you'll never have an understanding of flight.
>
>By the way, if you got your lard ass out of your chair and got
>some excercise, you wouldn't overgross the training ships you
>might be able to fly.

[Ron Natalie]

Dave wrote:
> Umm... OK.
>
> So may I ask what was wrong with his other two paragraphs?
>
They all repeat the same stupid irrelvent point.

In fact, the key of partial panel appraoch is simple.
If you aren't changing altitude and you aren't changing
heading (either by GPS or compass) then you are straight
and level. In fact, a GPS with a fast enough refresh rate
is as good (perhaps) better than a needle-ball gauge and
even your average portable is a whole lot better than the
whiskey compass.

[Mxsmanic]

Ron Natalie writes:

> If you aren't changing altitude and you aren't changing
> heading (either by GPS or compass) then you are straight
> and level.

GPS doesn't know your heading. It only knows your ground track, which
isn't the same thing.

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[Brad[_1_]]

On Feb 4, 9:38 pm, Mxsmanic > wrote:
> Ron Natalie writes:
> > If you aren't changing altitude and you aren't changing
> > heading (either by GPS or compass) then you are straight
> > and level.
>
> GPS doesn't know your heading. It only knows your ground track, which
> isn't the same thing.
>
> --
> Transpose mxsmanic and gmail to reach me by e-mail.

It doesn't matter. If your relative track doesn't change and you're
coordinated, then you're not banking.

Unless you're in a tornado.

[Newps]

Mxsmanic wrote:

> Danny Deger writes:
>
>
>>I am thinking about buying a 1946 Taylorcraft that has NO gyros at all on
>>the panel. I really want at least a turn and bank so I want die if I loose
>>reference to the horizon for any reason. I have been told that the heading
>>information from a GPS is good enough to do the function of a turn and bank
>>and allow emergency operations without having a visual horizon reference.
>>Is this correct?
>
>
> A GPS can only determine your track over the ground, which may not be
> your heading.




True, but utterly irrelevant.





If there is no wind, both are the same, but if there is
> any wind, your heading could be significantly different from your
> ground track.


Completely and totally irrelevant.



>
> GPS cannot determine your bank angle.


No need to.





In theory a GPS could determine
> if you appear to be making a standard turn, if there is no wind.


The wind is irrelevant. Speed and rate of turn are all that is needed.


All the rest of the drivel snipped.

[Newps]

Mxsmanic wrote:

> Ron Natalie writes:
>
>
>>If you aren't changing altitude and you aren't changing
>>heading (either by GPS or compass) then you are straight
>>and level.
>
>
> GPS doesn't know your heading. It only knows your ground track, which
> isn't the same thing.
>

And why do you even remotely care what your heading is?

[Morgans]

"J. Severyn" > wrote

> Actually there are specialized GPS units that can determine attitude and
> they have been around for at least 10-12 years. Google the "Trimble TANS
> Vector" and you will see one of the earlier units.
> http://trl.trimble.com/docushare/dsweb/Get/Document-19330/20997-00-C.pdf
> They operate by using at least 3 antennae (usually four antennae) and
> directly determine roll, pitch and yaw using carrier phase differences
> from
> the GPS satellites. Of course this is not the way the portable units
> derive
> the HSI info.

That's some cool stuff.

It seems as though I recall this subject coming up a few years ago in the
homebuilt group, and nobody came forward with a system like this one.

I didn't see a price associated with it anywhere.

Is this a case of, "if you have to ask, you can't afford it?" <g>
--
Jim in NC

[Mxsmanic]

Brad writes:

> It doesn't matter. If your relative track doesn't change and you're
> coordinated, then you're not banking.

A GPS unit doesn't know if you're coordinated. And if your track _is_
changing, it doesn't know why.

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[Mxsmanic]

Newps writes:

> And why do you even remotely care what your heading is?

Sometimes you have to maintain a heading; sometimes you have to follow
a track.

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[Mxsmanic]

Newps writes:

> True, but utterly irrelevant.

It's highly relevant. GPS can't be used as a bank indicator, nor can
it be used as a turn indicator. All it can do is measure changes in
your track, which it does by checking your position over the ground at
regular intervals. It doesn't know the attitude of the aircraft, and
it doesn't know if you are actually turning.

> The wind is irrelevant. Speed and rate of turn are all that is needed.

A change in the wind will change your track as measured by the GPS.
The GPS does not know if this is a turn or just a wind change. And if
you turn, the GPS cannot distinguish that from a wind change, either.

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[Thomas Borchert]

Dave,

> So may I ask what was wrong with his other two paragraphs?
>

Download the free (I think) simulator for the 196, 296, 396 or 496
handheld GPS navigators from Garmin and try the instruments page.
You'll see what Ron means. In fact, IIRC the 296 is simulated in MSFS,
so maybe it is shown there.

--
Thomas Borchert (EDDH)

[Thomas Borchert]

Danny,

> I have been told that the heading
> information from a GPS is good enough to do the function of a turn and bank
> and allow emergency operations without having a visual horizon reference.
>

Aviation Consumer has tried flying only with reference to the instruments page
on a Garmin 296 and 496. That page emulates the standard six-pack derived from
GPS data. They say it worked. They also said the 5 Hz vs 1 Hz update rate of
the 496 improves the concept a lot.

--
Thomas Borchert (EDDH)

[Brad[_1_]]

On Feb 5, 5:38 am, Mxsmanic > wrote:
> A GPS unit doesn't know if you're coordinated. And if your track _is_
> changing, it doesn't know why.

[Disclaimer: the following post is for the purpose of clarification
to the greater aviation community. I realize that arguing with this
delta alpha is a complete waste of time.]

Your statement does not make sense. Of course the GPS does not know
if you're coordinated. I doesn't need to. You can see the ball
yourself. If the ball is caged, and your ground track is changing,
you are by definition in a bank. End of story.

[Newps]

Mxsmanic wrote:

> Newps writes:
>
>
>>And why do you even remotely care what your heading is?
>
>
> Sometimes you have to maintain a heading; sometimes you have to follow
> a track.




So now you're changing the subject? Good one.

[Newps]

Mxsmanic wrote:

> Newps writes:
>
>
>>True, but utterly irrelevant.
>
>
> It's highly relevant. GPS can't be used as a bank indicator, nor can
> it be used as a turn indicator. All it can do is measure changes in
> your track, which it does by checking your position over the ground at
> regular intervals. It doesn't know the attitude of the aircraft, and
> it doesn't know if you are actually turning.


All you care about is that you're actually turning. Or not turning.
The GPS does very well at that. Irrelevant the attitude of the
aircraft, the turn coordinator isn't telling you that anyway.

>
>
>>The wind is irrelevant. Speed and rate of turn are all that is needed.
>
>
> A change in the wind will change your track as measured by the GPS.


Irrelevant.




> The GPS does not know if this is a turn or just a wind change. And if
> you turn, the GPS cannot distinguish that from a wind change, either.
>

Yawn.

[Newps]

Thomas Borchert wrote:

> Danny,
>
>
>>I have been told that the heading
>>information from a GPS is good enough to do the function of a turn and bank
>>and allow emergency operations without having a visual horizon reference.
>>
>
>
> Aviation Consumer has tried flying only with reference to the instruments page
> on a Garmin 296 and 496. That page emulates the standard six-pack derived from
> GPS data. They say it worked. They also said the 5 Hz vs 1 Hz update rate of
> the 496 improves the concept a lot.


>

I think that's the crucial part. If the update rate is too slow it's
almost worse than nothing.

[karl gruber[_1_]]

"Brad" > wrote in message
ps.com...
>
If the ball is caged, and your ground track is changing,
> you are by definition in a bank. End of story.


No.


A wind shift will also alter the ground track. Listen to MX, the "idiot
savant" of this newsgroup.

Karl

[Peter Dohm]

> >
> > Aviation Consumer has tried flying only with reference to the
instruments page
> > on a Garmin 296 and 496. That page emulates the standard six-pack
derived from
> > GPS data. They say it worked. They also said the 5 Hz vs 1 Hz update
rate of
> > the 496 improves the concept a lot.
>
>
> >
>
> I think that's the crucial part. If the update rate is too slow it's
> almost worse than nothing.

Even the 5 Hz would drive me nuts!

[[email protected]]

A few years ago I wrote my own Flight Management software. It
contains obvious things like a moving map, nearest airports etc. , but
it also contained a GPS derived attitude indicator. As has been
suggested here earlier, the GPS gives me lon, lat and hopefully
altitude. My program then actually calculates the rate of ascent/
descent and left/right turn. This coupled with the ground speed gives
you enough information to deduce what the horizon would look like.
Now it makes of course some assumptions, like that the turn is
coordinated, this can be easily verified by the slip/skid ball, which
BTW has a fairly high MTBF. The principles here are somewhat similar
to a partial panel. What makes this approach actually useful is that
it combines the GPS information into a very simple Attitude Indicator
like display. Now if you use a device like NavMan the update rate is
once every 2 seconds which renders this approach absolutely useless,
normally the cheap devices SirF2 and 3 outputs in the 1Hz (Once a
second) range. I have flown under the hood with my device and a
safety pilot and I am able to keep it right-side-up. I am about to
try it with the 5Hz (Garmin GPS18-5) and I am pretty confident that
the usefulness will be quite good. I have presented this approach,
which works on Pocket PCs to my local EAA chapter. I am thinking of
making it available, despite this controversial feature.
Take a look at the Flyer below.

http://www.monroemobile.com/Flyer.jpg

Cheers,
SwedeFlyer

[Mxsmanic]

Brad writes:

> Your statement does not make sense. Of course the GPS does not know
> if you're coordinated. I doesn't need to. You can see the ball
> yourself. If the ball is caged, and your ground track is changing,
> you are by definition in a bank. End of story.

I was talking about using GPS to measure turn and bank.

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[Mxsmanic]

Newps writes:

> So now you're changing the subject? Good one.

No. I'm trying to illustrate, in multiple ways, why a GPS receiver
alone cannot serve to measure banking or turning.

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[Mxsmanic]

Newps writes:

> All you care about is that you're actually turning. Or not turning.
> The GPS does very well at that.

No, it does not. The GPS knows only your ground track. Nothing else.
If you are flying straight and level, and the wind changes, your
ground track may show a turn, even though you haven't turned in the
air. If you turn as the wind changes, your ground track may show no
change, even though you are turning and banking in the wind.

Thus, a GPS alone cannot serve as a turn and bank indicator. QED.

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[Mxsmanic]

Nomen Nescio writes:

> Well, just for s**ts & grins, I just did a flight on MSFS....In IMC........1000ft
> ceiling, where I took off, climbed to 3000 ft, flew over another airport (20nm
> away), turned around, flew back, and landed at the same airport. I did
> this using NOTHING but the altimeter and GPS. It wasn't pretty......but I did it.
> Oh, and I enabled the "real weather" option....kinda windy here in the NE, today.

All well and good ... but how did you determine your bank angle and
rate of turn with the GPS?

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[Mxsmanic]

writes:

> A few years ago I wrote my own Flight Management software. It
> contains obvious things like a moving map, nearest airports etc. , but
> it also contained a GPS derived attitude indicator. As has been
> suggested here earlier, the GPS gives me lon, lat and hopefully
> altitude. My program then actually calculates the rate of ascent/
> descent and left/right turn. This coupled with the ground speed gives
> you enough information to deduce what the horizon would look like.
> Now it makes of course some assumptions, like that the turn is
> coordinated, this can be easily verified by the slip/skid ball, which
> BTW has a fairly high MTBF.

How do you know and allow for the wind speed?

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[Newps]

Mxsmanic wrote:
> Newps writes:
>
>
>>So now you're changing the subject? Good one.
>
>
> No. I'm trying to illustrate, in multiple ways, why a GPS receiver
> alone cannot serve to measure banking or turning.




And you fail utterly. As usual.

[Newps]

Mxsmanic wrote:

> Newps writes:
>
>
>>All you care about is that you're actually turning. Or not turning.
>>The GPS does very well at that.
>
>
> No, it does not. The GPS knows only your ground track. Nothing else.


Nothing else is needed, as has been pointed out before. If you had any
actual flying experience you would know the wind is irrelevant. Even
flying thru a front is irrelevant.



> If you are flying straight and level, and the wind changes, your
> ground track may show a turn, even though you haven't turned in the
> air. If you turn as the wind changes, your ground track may show no
> change, even though you are turning and banking in the wind.

Not relevant in the real world.

[[email protected]]

On Feb 5, 3:10 pm, Mxsmanic > wrote:
> writes:
> How do you know and allow for the wind speed?

For real practical purposes it really does not matter a lot. Note
that I am interested in the RATE of turn. Of course if the wind
direction and speed changes every second by a very large amount you
may have false "temporary attitudes", now that would constitute pretty
severe turbulence and wind sheer I would imagine. I can go through my
calculations but as I recall a standard rate turn 3 degrees /second
turn at 120kts will yield a 17 degree horizon (coordinated) I think.

An example:Let's say that my magnetic compass shows due North (Mag
Var = 0) I am going at 100kts TAS wind is 10kts from the west 270.
This means that my ground track is appr 006 Magnetic. I don't care,
what I care about is that the rate of change to my ground track (first
derivative) is the same when I do a left coordinated bank versus a
right coordinated turn, obviously my ground track profile will be
different but I don't care, I am not doing turns around a point.
That's the premise and it seems to work fairly reasonably well,
believe me if everything else failed ...

[Mxsmanic]

Newps writes:

> And you fail utterly. As usual.

In any communication system, failures can occur at either the
transmitting or the receiving ends.

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[Mxsmanic]

Newps writes:

> Nothing else is needed, as has been pointed out before. If you had any
> actual flying experience you would know the wind is irrelevant. Even
> flying thru a front is irrelevant.

Explain how you distinguish between wind changes and turns by looking
at a ground track alone.

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[Newps]

Mxsmanic wrote:

> Newps writes:
>
>
>>Nothing else is needed, as has been pointed out before. If you had any
>>actual flying experience you would know the wind is irrelevant. Even
>>flying thru a front is irrelevant.
>
>
> Explain how you distinguish between wind changes and turns by looking
> at a ground track alone.

What we're trying to do here is keep the plane flying safely straight
and level after the loss of certain instruments. Altitude is much less
important than right/left. As long as the GPS is steady on a ground
track I'm safely upright. No amount of crosswind or frontal passage
wind shift will alter that. I may in fact be in a very slight bank to
maintain a ground track, doesn't matter as it on the order of a degree
or less. So I don't care what the drift is, the primary importance is
keeping the plane upright. I'll also eliminate drift by selecting a
waypoint to go to. Stay on the line drawn by the GPS and the heading is
irrelevant. I hand fly hundreds of miles on cross countries without
getting more than a tenth of a mile off the straight line between the
two points. All this and never looking at the heading indicator. Don't
need it, just look at the line.

[Robert M. Gary]

On Feb 4, 2:30 pm, "Tony" > wrote:
> How are you going to determine bank with a GPS?

The Garmin handhelds show a mini panel complete with a turn
corrdinator. The GPS knows your rate of turn. However, on the 296
there is enough delay that it isn't really simple to fly under the
hood on.

-Robert

[Mxsmanic]

Nomen Nescio writes:

> You're the expert!
> You figure it out.

It cannot be done.

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[Gig 601XL Builder]

Mxsmanic wrote:
> Nomen Nescio writes:
>
>> You're the expert!
>> You figure it out.
>
> It cannot be done.


Ok Anthony, explain how Garmin produces this page.

http://www.garmin.com/products/gpsmap396/gallery/image19.html

[Mxsmanic]

Gig 601XL Builder writes:

> Ok Anthony, explain how Garmin produces this page.
>
> http://www.garmin.com/products/gpsmap396/gallery/image19.html

By taking a screenshot of the unit.

As for the simulated instrument at the lower left, it provides only
rough information on the rate of a turn, not an indication of bank
angle. I note that Garmin itself doesn't appear to explain what the
simulated instrument is supposed to show exactly.

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[Newps]

Robert M. Gary wrote:
> On Feb 4, 2:30 pm, "Tony" > wrote:
>
>>How are you going to determine bank with a GPS?
>
>
> The Garmin handhelds show a mini panel complete with a turn
> corrdinator. The GPS knows your rate of turn. However, on the 296
> there is enough delay that it isn't really simple to fly under the
> hood on.

I thought I heard that the new 296's had the better processor of the
396/496. Did that happen or not?

[Thomas Borchert]

Peter,

> Even the 5 Hz would drive me nuts!
>

Yeah, but you might live to tell us about it.

--
Thomas Borchert (EDDH)

[Mxsmanic]

Nomen Nescio writes:

> No. YOU can't do it.

The GPS unit cannot do it. Nor can any human being when limited to
the same information that the GPS has.

> I can do it.
> Real pilots CAN do it.
> Why?

Not why, how. Show me how it's done. All you have is the ground
track of the aircraft. Explain how to calculate the bank angle from
this. Indeed, explain how to even unambiguously recognize a turn.

The rest of your tirade fails to answer the questions above despite
its length, and so I shall not address it here.

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[Roy Smith]

In article >,
Thomas Borchert > wrote:

> Danny,
>
> > I have been told that the heading
> > information from a GPS is good enough to do the function of a turn and bank
> > and allow emergency operations without having a visual horizon reference.
> >
>
> Aviation Consumer has tried flying only with reference to the instruments
> page
> on a Garmin 296 and 496. That page emulates the standard six-pack derived
> from
> GPS data. They say it worked. They also said the 5 Hz vs 1 Hz update rate of
> the 496 improves the concept a lot.

I can't say I have a lot of experience doing this, but I've had a few
students who own these things try it. I put them under the hood, put us
into an unusual attitude, then they get to recover using just the synthetic
six-pack in their handheld GPS.

My experience so far is that if you take your hands off the yoke and just
apply whatever rudder inputs are needed to make the synthetic HSI indicate
a steady heading, you'll recover. It won't be pretty (or comfortable), but
you'll keep the dirty side down and won't pull the wings off the airplane.

The pitch information you get from the synthetic AI, VSI, ASI, and ALT
doesn't seem to be good enough to be useful, but fortunately most light
planes are pretty stable in pitch. Ride out a few fugoids while keeping
the HSI pointed in the same direction, and eventually you'll end up in a
stable attitude.

Mostly we do this in the Archers and Arrows. I'm not sure how well it
would work in something a bit less stable like a Bonanza or Mooney.

[[email protected]]

On Feb 6, 4:13 am, Mxsmanic > wrote:
> Nomen Nescio writes:
> > No. YOU can't do it.
>
> The GPS unit cannot do it. Nor can any human being when limited to
> the same information that the GPS has.
>
> > I can do it.
> > Real pilots CAN do it.
> > Why?
>
> Not why, how. Show me how it's done. All you have is the ground
> track of the aircraft. Explain how to calculate the bank angle from
> this. Indeed, explain how to even unambiguously recognize a turn.
>
> The rest of your tirade fails to answer the questions above despite
> its length, and so I shall not address it here.
>
> --
> Transpose mxsmanic and gmail to reach me by e-mail.

If you're interested I can expand slightly more on the "Mathematics"
that is involved in determining a virtual horizon. Please note that
there may be a discrepancy if you are not coordinated, this is also
true of the regular six-pack. Do the following:
Fly Straight and level, then apply full left rudder and strong right
aileron/bank. You might see that the turn/bank coordinator will show
a turn to the left, whereas the AI indicator shows a bank to the
right. Obviously in this case the GPS Horizon would show a bank to
the left, similarly the Garmin x96 HSI page will show a turn to the
left.
Cheers,
SwedeFlyer

[Mxsmanic]

writes:

> If you're interested I can expand slightly more on the "Mathematics"
> that is involved in determining a virtual horizon. Please note that
> there may be a discrepancy if you are not coordinated, this is also
> true of the regular six-pack.

If you cannot be sure that you are coordinated, you cannot hope to
calculate the bank angle.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Capt. Geoffrey Thorpe]

"Danny Deger" > wrote in message
...
>I am thinking about buying a 1946 Taylorcraft that has NO gyros at all on
>the panel. I really want at least a turn and bank so I want die if I loose
>reference to the horizon for any reason. I have been told that the heading
>information from a GPS is good enough to do the function of a turn and bank
>and allow emergency operations without having a visual horizon reference.
>Is this correct?
>


Some time ago (a few months?) someone (an insructor - don't remember who)
posted a note either here or R.A.Student about giving a flight review and
covering up ALL the gyro's and the student kept flying on track without
falling off into a turn as expected. After a period of time, the instuctor
inquired as to how this was possible (thinking the student was "peeking"
under the hood) and was informed that he/she was using the track indication
from the GPS to keep it straight.

So, apparently, it can work.

I tried to find the post - no joy. You are on your own if you want to dig up
the details.

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

[Ron Natalie]

Mxsmanic wrote:
> writes:
>
>> If you're interested I can expand slightly more on the "Mathematics"
>> that is involved in determining a virtual horizon. Please note that
>> there may be a discrepancy if you are not coordinated, this is also
>> true of the regular six-pack.
>
> If you cannot be sure that you are coordinated, you cannot hope to
> calculate the bank angle.
>
I've never had the freaking ball fail on me yet. Most aircraft
in cruise regime have no problem being coordinated without pilot
input...they're specifically optimized for that.

[Bob Moore]

Mxsmanic wrote
> It cannot be done.

But there are many still trying.

http://www.approach-systems.com/apic.asp

Bob Moore