Electronic horizon?

I recently saw the write-up on the Stratomaster AHRS-2 system. Its
American uncertified kit that shows a ribbon compass, T&S and artificial
horizon on a single LCD display that fits a standard 80mm panel hole.

It only uses 200 mA at 12v, is light and costs about GP 100 ($US 180) more
than an ex-military horizon, T&S and compass. I like that and the ability
to put the lot in just one dial on the panel.

Is there any experience out there with this gadget?

--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

I just checked their web site. $180 sounded too good to be true. It was.
The AHRS-2 lists for $1200.

John

Martin,

I have flown with this instrument, it works well. It will tumble after
several minutes of extreme bank angles. Even higher priced instrument
in the $3000 to $5000 range have a cage function for acrobatic
maneuvers or extreme bank angles.

Please see my web site for more info and pricing
http://www.craggyaero.com/solidstate.htm

Richard
www.craggyaero.com

On Thu, 25 Aug 2005 18:17:57 -0600, John Scott wrote:

I just checked their web site. $180 sounded too good to be true. It
was.
The AHRS-2 lists for $1200.

Yeah, that sounds about right: I actually said it was about $200 LESS THAN
a standard compass + mechanical T&S + artifical horizon. The price I saw
was GBP 695.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Thu, 25 Aug 2005 20:53:43 -0700, rhpf wrote:

Martin,

I have flown with this instrument, it works well. It will tumble after
several minutes of extreme bank angles. Even higher priced instrument in
the $3000 to $5000 range have a cage function for acrobatic maneuvers or
extreme bank angles.

This instrument group is one that I'd almost never use during normal XC:
the reason I'm looking is that when/if I do some wave flying I'd like to
have these displays onboard in case of canopy icing and/or finding
the slot slammed shut below me. Would you trust it for that? I'm asking
because I've heard stories that continuous circling would tumble it.

--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

Even though it doesn't have pitch info, I've been really happy with the
Trutrak

http://www.trutrakflightsystems.com/...struments.html

Powers up in 3 seconds, even in a crank and bank turn, so can be left off
until needed. The "sky and ground" display is more intuitive than a turn
coordinator or needle and ball. In use, the horizon display closely tracks
the real horizon. For $445, cheap insurance.

bumper
(no affiliation to Trutrak)

"Martin Gregorie" wrote in message
news
On Thu, 25 Aug 2005 18:17:57 -0600, John Scott wrote:

I just checked their web site. $180 sounded too good to be true. It
was.
The AHRS-2 lists for $1200.

Yeah, that sounds about right: I actually said it was about $200 LESS THAN
a standard compass + mechanical T&S + artifical horizon. The price I saw
was GBP 695.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

Martin Gregorie wrote:

On Thu, 25 Aug 2005 20:53:43 -0700, rhpf wrote:

I have flown with this instrument, it works well. It will tumble after
several minutes of extreme bank angles.

Would you trust it for that? I'm asking
because I've heard stories that continuous circling would tumble it.

The post you're answering to tells it clearly enough, I think. Extreme
bank angle is a pretty normal attitude in a glider.

The only instrument that will never tumble, by construction principle,
is the needle. So if you're looking for an emergency instrument, install
a classic, gyro driven needle. I wouldn't want to do serious cloud
flying with only a needle in a glass ship, but for an emergency descent
with open spoilers it's good enough.

Stefan

bumper wrote:

Even though it doesn't have pitch info, I've been really happy with the
Trutrak

http://www.trutrakflightsystems.com/...struments.html

I consider this instrument dangeruous because a trained pilot *will*
confuse it with a horizon. And an untrained pilot shouldn't fly in IMC
in the first place.

Stefan

Well, let's see, last I checked, I'm a "trained pilot" (SEL, instrument,
glider), and *I* haven't confused it yet. While I respect your opinion, I'd
like to know what data you're basing it on.

Agreed, the Trutrak does sort of "resemble" a full fledged horizon or AI,
but even at first glance it's pretty obvious that it's not the same.

I'm not suggesting that people go out and fly IMC with the Trutrak. Like the
Garmin 196 panel page, the Trutrak, an old mechanical gyro, or damn near
anything is better than nothing for inadvertent or emergency IMC. Many of us
know dead folks who would still be alive if they had one of these devices.

BTW, the Trutrak doesn't tumble. Like a needle and ball, it simple stops
increasing the displayed bank angle once you get steeper than say 60
degrees. It is available set up for both 1 and 2 minute turns (1 minute
recommended for glider).

I've also flown with a mechanical gyro 1 minute needle and ball installed in
a Stemme I recently sold, so I have experience with several instruments. In
order of preference, and assuming one doesn't have a full AI, I'd rate the
Trutrak first, then the Garmin 196 (that is amazingly good), and the
mechanical gyro needle and ball last - - though they will all do the job
given adequate pilot training flying partial panel IMC.

bumper


"Stefan" wrote in message
...
bumper wrote:

Even though it doesn't have pitch info, I've been really happy with the
Trutrak

http://www.trutrakflightsystems.com/...struments.html

I consider this instrument dangeruous because a trained pilot *will*
confuse it with a horizon. And an untrained pilot shouldn't fly in IMC in
the first place.

Stefan

There are several PDA based 'glass cockpit' software packages that appear to
work well. They derive bank attitude from TAS (or GS if TAS is not
available) and the rate of change of ground track. Pitch data is derived
from the rate of change of airspeed. 'Heading' is actually ground track but
that is good enough.

Since many glider pilots already have a PDA in the cockpit, these might be
good enough for an emergency. Simply have the 'glass cockpit' running in
the background and switch to it if the need arises. The beauty is that no
additional hardware is needed beyond what is already in the glider.

FWIW, I tried a simulated 'blind let down' using only the wet compass in the
back seat of a G103. With the glider on a southerly heading, I used the
southerly leading error to keep the wings level and hold the heading. I was
able to do this for about 10 minutes under the 'hood' without outside
reference.

For those readers not aware of this trick, a magnetic compass senses not
only the N-S magnet field but also the 'dip' angle. While on a southerly
heading in mid northern latitudes, the magnetic compass will indicate a turn
as soon as a wing is down and before a turn actually starts. Banking the
glider left and right as needed to keep the compass on S will keep the wings
level. This is very tricky in a fast airplane but surprisingly easy in a
slow glider as long as the air isn't very turbulent. (For out friends in
the Southern Hemisphere this trick requires a north heading.)

Bill Daniels


"Martin Gregorie" wrote in message
news
On Thu, 25 Aug 2005 20:53:43 -0700, rhpf wrote:

Martin,

I have flown with this instrument, it works well. It will tumble after
several minutes of extreme bank angles. Even higher priced instrument
in
the $3000 to $5000 range have a cage function for acrobatic maneuvers or
extreme bank angles.

This instrument group is one that I'd almost never use during normal XC:
the reason I'm looking is that when/if I do some wave flying I'd like to
have these displays onboard in case of canopy icing and/or finding
the slot slammed shut below me. Would you trust it for that? I'm asking
because I've heard stories that continuous circling would tumble it.

--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |