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Artificial Horizon
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bicyclop(at)pacbell.net
Guest

Posted: Thu Jan 19, 2006 11:52 am Post subject: Artificial Horizon

I did handle the ADI on the bench at Sun'N'Fun. I didn't try a

hammerhead with it, but it did seem to track bank angle as well as any

gyro I've done the same with, regardless of pitch attitude. It did give

me weird indications in pitch and they told me it would because there

was no change in altitude to work with. It initially showed the pitch up

and then returned to level. 



They said that is very flyable. Their reasoning, as I understand it, is

that the actual pitch attitude of the aircraft is less important to your

moment to moment control inputs than having an indication of what the

trend is. In other words, if you wish to climb, descend or fly level,

the instrument gives you a clear indication of the effect of your

control inputs on the flight path. If you were to get behind the power

curve, the display might not be so intuitive. They have a flashing

airspeed warning for that condition. I don't know how easy it would be

to figure out what to do if the nose was up and the vertical speed began

to go negative using only the ADI for reference. Definitely not

something I would want to try for the first time in the clouds. Your

other instruments, notably the airspeed indicator and altimeter, would

tell the story.



I asked them what would happen if you got inverted in the clouds. Their

reply was that you'd be in a world of hurt no matter what kind of

attitude indicator you were using, but they felt that the with ADI it

would be at least as easy to prevent such a condition from occurring as

with an AH.



I was impressed with the instrument at the airshow. I would love to hear

from someone who's flying it.



Pax,



Ed Holyoke



--

Steve Glasgow

Joined: 10 Jan 2006
Posts: 674

Posted: Thu Jan 19, 2006 12:48 pm Post subject: Re: Artificial Horizon

Thanks to all who replied to my orriginal post.  Your input has been very helpfull.  At present I'm leaning toward the ADI by Trutrack.

_________________
Steve Glasgow-Cappy
Cappy's Toy
RV-8 N123SG

hawk(at)digisys.net
Guest

Posted: Fri Jan 20, 2006 12:37 pm Post subject: Artificial Horizon

Beating this dead horse one more (and like you, I hope last) time...



My friend Maurie powered up his new TruTrak ADI on the bench this morning, 

and the results of extensive testing are:



1.  Tilt the ADI 30 degrees to the side on the bench.  After a variable 

small transient, the display reverted to the level centered position.



2.  Tilt the unit on its side (90 deg roll angle).  Same result, washed back 

to level, centered and stayed there.



3.  Rapid pitch to 20 degrees Nose Up and hold.  After a slight upward 

transient, went to level centered and stayed there.



Summary:  No roll angle or pitch angle information is displayed by the unit. 

It is NOT an attitude indicator.



Functionally it seems to be a Turn Coordinator with an integrated VSI.*



* There may be some inputs from roll or pitch acceleration cues used to 

"quicken" the display, but they seem to go away as soon as the acceleration 

is removed and a steady-state roll angle or pitch angle is established.



Hawkeye





---

Steve Glasgow

Joined: 10 Jan 2006
Posts: 674

Posted: Sat Jan 21, 2006 5:14 am Post subject: Re: Artificial Horizon

Here is another option.  Does anyone have any experence with it?



http://www.lightflying.com.au/Stratomaster%20Pages/Artificial%20Horizons%20&%20Compasses.htm

_________________
Steve Glasgow-Cappy
Cappy's Toy
RV-8 N123SG

Bruce(at)glasair.org
Guest

Posted: Sat Jan 21, 2006 6:35 am Post subject: Artificial Horizon

I really don't understand this rush to go out and bet your life on untested,

uncertified instrumentation. 



Bruce

www.glasair.org

 



--

ebundy(at)speedyquick.net
Guest

Posted: Sat Jan 21, 2006 8:05 am Post subject: Artificial Horizon

I don't know if you're referring to one particular unit, or new instrument

technology in general, but having had a gyro failure in IMC, I understand it

very well.  Also, having had to pay for several vacuum gyro/pump rebuilds I

LOVE having an electronic EFIS and digital engine management system.



Anyone want to buy a complete Rapco vacuum system and AH?



Ed Bundy

 	  Quote: 	
		   I really don't understand this rush to go out and bet your life

 on untested,

 uncertified instrumentation.



 Bruce


	


--

Bruce(at)glasair.org
Guest

Posted: Sat Jan 21, 2006 8:50 am Post subject: Artificial Horizon

While a transistor or computer chip might have a greater MTBF than

mechanical gyros, The software that drives these new wonders remains, for

the most part, untested. Sure the companies make some rudimentary tests but

nothing like the full DO178 compliant tests required of certificated

electro-whizzys.



Bruce

www.glasair.org

 



--

rv8ch

Joined: 10 Jan 2006
Posts: 250
Location: Switzerland

Posted: Sat Jan 21, 2006 9:38 am Post subject: Artificial Horizon

I agree that the software is the weak point in any computer

system.  Always has been, probably always will be.  There

are many things, however, that are higher risk than these

devices, including the electric system.  I've read of

forced landings due to electric system failure, but

I can't recall a single crash due to an uncertified

electronic AI failing.  Not saying it has not happened,

but I have not seen any reports.



I think a well-designed and implemented electric system,

a la Bob N., and two independent AIs from different

manufacturers will be *a lot* more reliable than a

certified vacuum pump and certified gyro AIs.

Bruce Gray wrote:

[quote] 

 

 While a transistor or computer chip might have a greater MTBF than

 mechanical gyros, The software that drives these new wonders remains, for

 the most part, untested. Sure the companies make some rudimentary tests but

 nothing like the full DO178 compliant tests required of certificated

 electro-whizzys.

 

 Bruce

 www.glasair.org

  

 

 --

_________________
Mickey Coggins
http://www.rv8.ch/

khorton01(at)rogers.com
Guest

Posted: Sat Jan 21, 2006 10:26 am Post subject: Artificial Horizon

On 21 Jan 2006, at 11:52, Bruce Gray wrote:



 	  Quote: 	
		   



 While a transistor or computer chip might have a greater MTBF than

 mechanical gyros, The software that drives these new wonders  

 remains, for

 the most part, untested. Sure the companies make some rudimentary  

 tests but

 nothing like the full DO178 compliant tests required of certificated

 electro-whizzys.


	


DO-178 compliance only "ensures" that the software code has correctly  

implemented the specification that describes how it should function.   

DO-178 compliance does not ensure that the specification is correct  

and complete (it attempts to do this, but it fails).  I have done  

quite a bit of flight testing on aircraft with new systems with  

DO-178 compliant code.  Most of the problems that we find are due to  

problems with the functional specification - i.e. the coder did a  

perfect job incorporating a flawed specification.  There are often  

particular scenarios that the functional specification did not  

envision, and this leads to anomalous behaviour.



DO-178 compliant or not, the only way to determine if the system  

works correctly is to to a lot of testing, over the full range of  

conditions that the system will see in service.



Kevin Horton         RV-8 (finishing kit)

Ottawa, Canada

http://www.kilohotel.com/rv8

Bruce(at)glasair.org
Guest

Posted: Sat Jan 21, 2006 10:39 am Post subject: Artificial Horizon

That's because no one is left alive to tell us.



Bruce

www.glasair.org

 



--

Steve Glasgow

Joined: 10 Jan 2006
Posts: 674

Posted: Sat Jan 21, 2006 10:40 am Post subject: Re: Artificial Horizon

I really don't understand this rush to go out and bet your life on untested, 

uncertified instrumentation. 



Bruce 

www.glasair.org 



--



There is no rush.  Some of us have trashed our gyros doing acro and would like to find a solid state replacement that fits in the hole in our panels.

_________________
Steve Glasgow-Cappy
Cappy's Toy
RV-8 N123SG

Bruce(at)glasair.org
Guest

Posted: Sat Jan 21, 2006 10:43 am Post subject: Artificial Horizon

DO178 compliance, faults included, at least insures a known level of

functionality, otherwise, as I've said before, everyone is a beta tester.



Bruce

www.glasair.org

 



--

Bruce(at)glasair.org
Guest

Posted: Sat Jan 21, 2006 11:01 am Post subject: Artificial Horizon

If you use your airplane for acro why do you need gyros?



Bruce

www.glasair.org

 



--

rv6n6r(at)comcast.net
Guest

Posted: Sat Jan 21, 2006 11:50 am Post subject: Artificial Horizon

 	  Quote: 	
		  I really don't understand this rush to go out and bet your life on

untested,  uncertified instrumentation. 



Bruce 

www.glasair.org 


	


We are in a rush to get away from betting our lives on antiquated technology that has a proven track record of marginal reliability (truckload of FAA certification paperwork notwithstanding.)  Besides, no one's advocating doing away with the concept of independent backup instruments.



 	  Quote: 	
		   If you use your airplane for acro why do you need gyros?



Bruce

www.glasair.org


	


Okay, I get it now. You're on this list just to heckle us, right? Okay I'll humor ya..  Here's the deal -- few RVers can resist the occasional or even not so occasional loop, aileron roll, cuban-8, etc., whether or not some of us also fly IFR in order to get from point A to point B when the clouds are down low. These are versatile machines, why should the instrumentation be less so? 



Randall Henderson

RV-6



do not archive

Bruce(at)glasair.org
Guest

Posted: Sat Jan 21, 2006 12:50 pm Post subject: Artificial Horizon

No, I'm really not on this list to heckle you guys. My Glasair III has a 75k

panel and no EFIS, I do have an EHSI though. I did some serious research

into this subject (low cost EFIS) when I was making the decisions for my own

airplane. I'm just trying to pass on some of the information I uncovered and

the decision tree that led me to this point.



Let me give you the LONG story. The FAA has determined that in order for an

EFIS to be considered/certified in an aircraft as a PRIMARY attitude display

and means of navigation, it must meet several criteria. The main one's are

that there be dual independent systems with an electronic comparator/alerter

and a backup third tie breaker attitude gyro. I'm sure you all have seen the

certified Garmin G1000, Avidyne and Chelton certified single systems now

coming out without duel redundant systems. How did they do that? It's

simple, all these EFIS systems in certified airplanes are certified as

SECONDARY flight display systems, not PRIMARY. The old fashioned backup

steam gages are the primary flight instruments for the airplane.



What's the big deal? It has to do with human factors engineering

(man/machine interface). Data point - A recent FAA study showed that it took

the average GA pilot 4 seconds to respond (lower the nose) to an engine out

takeoff emergency. 4 seconds! That's a long time. Now, we've all looked at

these new displays, very pretty and HYPNOTIC. If they fail and don't alert

or go dark the average GA IFR pilot will take a long time to revert to

needle, ball, and airspeed. If you're at 400 AGL on the ILS looking for the

runway on an approach to minimums and the AHRS hits a bad line of code,

giving you an erroneous 10 degree nose down pitch command, you're toast. The

dual system/alerter/third gyro are there to try and give you a chance to

survive when time is of the essence.



Oh, you're a super pilot on partial panel and don't need all this redundant

stuff, good you make your choices and go. But just be aware of the pitfalls

of your decisions. Safer? I don't know. Time will tell. I just don't want

any of you guys to be among the statistics.



Bruce

www.glasair.org

 



--

mkellems(at)bellsouth.net
Guest

Posted: Sat Jan 21, 2006 12:58 pm Post subject: Artificial Horizon

Am I out of line by asking. Isn't the testing and trying of new ideas the 

core of Experimental Aviation?  Isn't that what it's all about?

Where would we be today in this "hobby" of ours without new untested ideas? 

One that comes to mind is the complete building of a fiberglass aircraft. 

Oh, and Do Not Archive.  Mike

---

Steve Glasgow

Joined: 10 Jan 2006
Posts: 674

Posted: Sat Jan 21, 2006 2:20 pm Post subject: Re: Artificial Horizon

Okay, I get it now. You're on this list just to heckle us, right? Okay I'll humor ya..  Here's the deal -- few RVers can resist the occasional or even not so occasional loop, aileron roll, cuban-8, etc., whether or not some of us also fly IFR in order to get from point A to point B when the clouds are down low. These are versatile machines, why should the instrumentation be less so? 



Randall Henderson 



[/quote]



Thanks Randall, I agree totally.  What is a Glasair anyway?

Can they go over the top and round and round?

_________________
Steve Glasgow-Cappy
Cappy's Toy
RV-8 N123SG

dbris200(at)sbcglobal.net
Guest

Posted: Sat Jan 21, 2006 5:38 pm Post subject: Artificial Horizon

Now come on guys, these transistors and ic's are mostly - yes - plastic! 

So Bruce might have a point, after all he knows plastic.



Dave

do not archive

Steve Glasgow wrote:



 	  Quote: 	
		  



Okay, I get it now. You're on this list just to heckle us, right? Okay I'll humor ya..  Here's the deal -- few RVers can resist the occasional or even not so occasional loop, aileron roll, cuban-8, etc., whether or not some of us also fly IFR in order to get from point A to point B when the clouds are down low. These are versatile machines, why should the instrumentation be less so? 



Randall Henderson 



	




Thanks Randall, I agree totally.  What is a Glasair anyway?

Can they go over the top and round and round?



--------

Steve Glasgow-Cappy

Cappy's Toy 

RV-8 N123SG





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=5752#5752





 

 

 





  




[/quote]

nyman(at)bellsouth.net
Guest

Posted: Sun Jan 22, 2006 7:40 am Post subject: Artificial Horizon

<<From: "Bruce Gray" <Bruce(at)glasair.org>



Sure the companies make some rudimentary tests but

nothing like the full DO178 compliant tests required of certificated

electro-whizzys.>>



Chelton did.  They use the same hardware and software in systems they sell 

to the experimental market.



Steve

N174AS

MEM



do not archive

Bruce(at)glasair.org
Guest

Posted: Sun Jan 22, 2006 8:42 am Post subject: Artificial Horizon

No, they don't. The software is the same, the hardware is not. Take for

example the AHRS, the certified units use the Crossbow 500 series or better,

the non-certified units use the Crossbow 400 series. The 400 series has just

been flagged by a Crossbow SB as VFR use only. They found a few software

bugs they have to iron out. The 400 series AHRS are not certified. 



FMI: http://www.xbow.com/Support/Support_pdf_files/Service_Letter_NAV425.pdf



Bruce

www.glasair.org

 



--

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