Digital Artificial Horizon

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tazin river
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Digital Artificial Horizon

Post by tazin river »

Hello there

Would you recommend this? https://www.aircraftspruce.ca/catalog/i ... review_tab

I don't fly IFR at all, basically only float and ski flying privately but it looks like I need to replace again the artificial horizon in our Cessna 180 (in the middle of the annual right now). This instrument was purchased brand new less than 2 years ago.

Thanks
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C-GKNT
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Re: Digital Artificial Horizon

Post by C-GKNT »

I got one of these because gyros don't last very long in helicopters due to the vibrations. It failed once (tumbled slowly) but was repaired under warrantee and has otherwise been reliable. I power mine off a USB charger.

Of course not certified but great for VFR/MVFR. It has a neat mounting clip that fits into a standard 3.5" instrument hole. A velocity source is needed (internal GPS) to resolve the attitude but you also get GPS heading/altitude. You may need to run the GPS antenna to someplace higher on your panel.

So yes, for your VFR only situation or as an IFR backup, I think its a good choice.

Glenn
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photofly
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Re: Digital Artificial Horizon

Post by photofly »

Doesn't it bother you to have everything depend on GPS?
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digits_
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Re: Digital Artificial Horizon

Post by digits_ »

photofly wrote:Doesn't it bother you to have everything depend on GPS?
From the description on the website, the GPS is only used to calculate ground speed, altitude, vertical speed, and ground track.

So if you use it as an attitude indicator combined with a classic altimeter, it looks like you are pretty safe, gps-fail wise.
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dash8dave
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Re: Digital Artificial Horizon

Post by dash8dave »

tazin river wrote:Hello there

Would you recommend this? https://www.aircraftspruce.ca/catalog/i ... review_tab

I don't fly IFR at all, basically only float and ski flying privately but it looks like I need to replace again the artificial horizon in our Cessna 180 (in the middle of the annual right now). This instrument was purchased brand new less than 2 years ago.

Thanks
I am probably missing something here and I'm sure that someone will point it out to me; but if you fly private day VFR, from what I see in the Regs, you don't need an attitude indicator. Its not until VFR OTT that an AI is required.


Division II — Aircraft Equipment Requirements

Power-driven Aircraft — Day VFR

605.14 No person shall conduct a take-off in a power-driven aircraft for the purpose of day VFR flight unless it is equipped with

(a) where the aircraft is operated in uncontrolled airspace, an altimeter;

(b) where the aircraft is operated in controlled airspace, a sensitive altimeter adjustable for barometric pressure;

(c) an airspeed indicator;

(d) a magnetic compass or a magnetic direction indicator that operates independently of the aircraft electrical generating system;

(e) a tachometer for each engine and for each propeller or rotor that has limiting speeds established by the manufacturer;

(f) an oil pressure indicator for each engine employing an oil pressure system;

(g) a coolant temperature indicator for each liquid-cooled engine;

(h) an oil temperature indicator for each air-cooled engine having a separate oil system;

(i) a manifold pressure gauge for each

(i) reciprocating engine equipped with a variable-pitch propeller,

(ii) reciprocating engine used to power a helicopter,

(iii) supercharged engine, and

(iv) turbocharged engine;

(j) a means for the flight crew, when seated at the flight controls to determine

(i) the fuel quantity in each main fuel tank, and

(ii) if the aircraft employs retractable landing gear, the position of the landing gear;

(k) subject to subsections 601.08(2) and 601.09(2), a radiocommunication system adequate to permit two-way communication on the appropriate frequency when the aircraft is operated within

(i) Class B, Class C or Class D airspace,

(ii) an MF area, unless the aircraft is operated pursuant to subsection 602.97(3), or

(iii) the ADIZ;

(l) where the aircraft is operated under Subpart 4 of this Part, or under Subpart 3, 4 or 5 of Part VII, radiocommunication equipment adequate to permit two-way communication on the appropriate frequency;

(m) where the aircraft is operated in Class B airspace, radio navigation equipment that will enable it to be operated in accordance with a flight plan; and

(n) where the aircraft is operated under Subpart 4 of this Part or under Subpart 5 of Part VII, radio navigation equipment that is adequate to receive radio signals from a transmitting facility.
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C-GKNT
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Re: Digital Artificial Horizon

Post by C-GKNT »

photofly wrote:Doesn't it bother you to have everything depend on GPS?
Yes...especially with ADS-B. I have serious concerns as to what will happen in a future ATC system when a GPS outage occurs.

As for attitude indicators, the sensors currently used require a velocity input to resolve the attitude. I have an Aspen PDF in one of my aircraft. It is hooked into the pitot static system and uses the airspeed as a velocity input. Hooking a portable device into the pitot static system is not feasible. Garmin G500/600/G1000's require a WASS GPS source to function as well. Mind you with the Aspen, if you get a pitot blockage the attitude indicator shows big red X's.

Glenn
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ahramin
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Re: Digital Artificial Horizon

Post by ahramin »

The D2 is a neat little unit but it's all GPS driven and for almost the same price you can get a GRT or Dynon EFIS that has air data as well.

In any case, you can't replace the artificial horizon in your 180 with any of these as they aren't certified. You can choose not to replace it and stick to day VFR. If you do that, you're not gaining much by spending a small pile of cash on a D2.
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C-GKNT
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Re: Digital Artificial Horizon

Post by C-GKNT »

digits_ wrote:
photofly wrote:Doesn't it bother you to have everything depend on GPS?
From the description on the website, the GPS is only used to calculate ground speed, altitude, vertical speed, and ground track.

So if you use it as an attitude indicator combined with a classic altimeter, it looks like you are pretty safe, gps-fail wise.
Digits,

See my previous post. With the Dynon like the Garmin G500/600/1000, no GPS--->No Attitude. With an Apsen pitot blockage ---> No attitude.

Glenn
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digits_
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Re: Digital Artificial Horizon

Post by digits_ »

C-GKNT wrote:
digits_ wrote:
photofly wrote:Doesn't it bother you to have everything depend on GPS?
From the description on the website, the GPS is only used to calculate ground speed, altitude, vertical speed, and ground track.

So if you use it as an attitude indicator combined with a classic altimeter, it looks like you are pretty safe, gps-fail wise.
Digits,

See my previous post. With the Dynon like the Garmin G500/600/1000, no GPS--->No Attitude. With an Apsen pitot blockage ---> No attitude.

Glenn
So the info on their website is wrong then ? All gps based would indeed be interesting...
The D2 Pocket Panel is a true artificial horizons based on the same technology that drives Dynon’s Electronic Flight Instrument Systems (EFIS).

MEMS-based AHRS (Attitude Heading Reference Systems) use calibrated solid state gyros and accelerometers to accurately determine true aircraft attitude without drift. A high-quality, highly sensitive GPS receiver is built into the D1/D2 to provide GPS ground speed, altitude, vertical speed, and ground track for enhanced flight situational awareness.
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photofly
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Re: Digital Artificial Horizon

Post by photofly »

It's possible the marketing material is being economical with the truth.

A mechanical AI has a self-erection mechanism to orient the gyro axis vertically. If the mechanism works too quickly the accumulated pitch and roll error in a turn will exceed the limit set by TSO-C4c - max 3° pitch or bank error after a 180° 1-minute turn at 156kts. If the mechanism doesn't erect quickly enough the instrument will fail if the vacuum is weak or the bearings drag, because it will precess away from the vertical. It turns out (if you do the maths) that if the gyro realigns back to the detected acceleration vector (which is vertical except when turning) no faster than 5°/minute that just about meets the TSO requirement.

A solid state AHRS has the same issue, not because of mechanical precession but because the solid state gyro zero-rotation output voltage drifts with time and temperature. The software has to align the internal vertical vector using gravity, and continuously (and very slowly) be realigning it to null out accumulated gyro drift. It's challenging reliably to get the drift sufficiently low across all temperatures (-20C to 60C, if someone leaves it in the sun on the instrument panel) to be able to get away with a sufficiently slow realignment rate that errors in a steady turn meet or are close to the requirements of TSO-C4c.

There are all sorts of tricks you can pull in electronics and in the software, but they all have disadvantages. If you have GPS you can tell when the aircraft is flying in a curved path and decompensate, and use a faster realignment rate.

If this unit doesn't absolutely require GPS to maintain and display attitude information I would expect its performance to be degraded without it.
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5x5
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Re: Digital Artificial Horizon

Post by 5x5 »

It's going to be more money, but the recently FAA STC approval for the Dynon D10A makes it a contender for certified aircraft. And opens the door somewhat for other manufacturers and will hopefully bring about a reduction in prices in the not too distant future.
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photofly
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Re: Digital Artificial Horizon

Post by photofly »

The Sandia SAI 340 looks interesting. I read that the FAA has approved it and similar devices for a straightforward replacement of the (only) vacuum gyro AI in certified aircraft:

https://www.aircraftspruce.ca/catalog/i ... -12817.php

It doesn't use GPS, but it does have pitot and static ports:
"Air-data is utilized to help refine the attitude solution during specific operational maneuvers. If air-data is lost, a Degraded Mode of operation is automatically entered. During this mode, errors in pitch may be observed during long accelerations or decelerations, however attitude information is always available - it is never removed or made un-available.
Errors will not exceed TSO limit specifications. Degraded Mode maintains basic attitude performance and is sufficient to maintain positive aircraft control for VFR and IFR operations. When operating in the Degraded Mode, an amber CROSS CHECK message may be displayed on the screen.
The SAI 340 is not sensitive to external magnetic fields. Altitude indication requires correct static pressure. Airspeed indication requires both correct pitot and correct static pressure. Slip indication has no functional dependencies."
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SuperchargedRS
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Re: Digital Artificial Horizon

Post by SuperchargedRS »

5x5 wrote:It's going to be more money, but the recently FAA STC approval for the Dynon D10A makes it a contender for certified aircraft. And opens the door somewhat for other manufacturers and will hopefully bring about a reduction in prices in the not too distant future.
And about damn time!

The article said under $2300. Frankly if they got approval for the sky view that would be a game changer and probably help drive garmin and aspins prices down too, win win

It's amazing the tech the experimental crowd gets to use, yet for "safety" the certified group is stuck in the 1950s - 1980s as far as our aircraft are concerned.

Image

http://www.ainonline.com/aviation-news/ ... d-aircraft

dash8dave wrote: I am probably missing something here and I'm sure that someone will point it out to me; but if you fly private day VFR, from what I see in the Regs, you don't need an attitude indicator. Its not until VFR OTT that an AI is required.
I think you're missing the chit happens aspect and the part where folks like to have some safety equipment even if the all knowing government doesn't force them to have it.

A skywagon can cover some ground as a cross country plane, and it doesn't take long until you're flying in haze, or accidentally go IMC, or..... A good attitude indicator is the best single instrument for events such as this, also a 180/5 is a nice platform and deserving of a good AI, and the mechanical units are...well...lacking


Ideally I'd like to get ride of my vac system in my IFR 185, I already have a EHSI and have been debating going to something like the recently certified dynon (which also has a built in battery backup) it would be nice to shed off the entire ancient and heavy vac system off my IO520, and loose the complex spinning mechanical gyros.
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tazin river
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Re: Digital Artificial Horizon

Post by tazin river »

I certainly agree with you Supercharger...

Had to replace the AH twice in the last 3 years...the vacuum pump once...and expect the DG to go soon....would be great to get rid of that entire loop!

Is the Dynon D10A approved for the 180/185? I see in the links provided above that it is only certified for the 150'a and 172's...

Cheers
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Re: Digital Artificial Horizon

Post by SuperchargedRS »

tazin river wrote:I certainly agree with you Supercharger...

Had to replace the AH twice in the last 3 years...the vacuum pump once...and expect the DG to go soon....would be great to get rid of that entire loop!

Is the Dynon D10A approved for the 180/185? I see in the links provided above that it is only certified for the 150'a and 172's...

Cheers
I don't think they have the skywagons on it yet, but if it's already for 172s and whatnot, I'd imagine it won't be long, personally I'd just hang out for a little while I toss a STC dynon in, give dynon a call and ask?
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Re: Digital Artificial Horizon

Post by beaverbob »

Strangely, the first thing I thought about it being digital was how it would be great for 4, and 8 point rolls. :rolleyes:
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Re: Digital Artificial Horizon

Post by AirFrame »

I have a D-10A in the RV... It's awesome. The amount of information presented in one place on that small screen is impressive.

@beaverbob, it lags a bit in roll, so if you relied on it for 4-point rolls you'd be off on each stop. :) I can complete a roll and look down to see the horizon on the D10A finish levelling off. It's not delayed by much, but you can catch it if you're quick. For general VFR flight, there is no noticeable lag.
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Re: Digital Artificial Horizon

Post by ragbagflyer »

Have you considered foreight with the synthetic vision and the stratus adsb/ahrs unit? It's an insanely cool package.
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Re: Digital Artificial Horizon

Post by Axial Flow »

Have you considered clicking on the bottom right hand corner and downloading 303 updated files! :)

How do you find the stratus 2 does for pitch/bank? I just ordered one and hoping it isn't a waste of cash for the backup AHRS function. Are you level in that picture? It kind shows a right bank but it is zero'd at the top.

ADS-B looks great when close to the border.

Any feedback on the Stratus 2 would be great.
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ahramin
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Re: Digital Artificial Horizon

Post by ahramin »

I think the picture is in a right bank Axial, not the airplane.
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