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3 phase 115V AC 400Hz light weight power supply

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frans(at)paardnatuurlijk.
Guest

Posted: Mon Mar 09, 2009 10:37 am Post subject: 3 phase 115V AC 400Hz light weight power supply

In my Europa, I would like to have an attitude indicator. Not for

instrument flying, but just "in case".

As I don't have a vacuum system, but dual alternators instead, the

attitude indicator had to be electrical.



These electrical attitude indicators are available for various prices,

but almost all of them fall into the "very expensive" range.

I decided to buy a Falcon 12 Volt gyro, to see if this would be usable.

Well, it worked initially, with a lot of noise, but apparently the

carefull removal and re-installation of the entire instrument panel was

enough to cause the instrument to get damaged. I will probably get this

thing repaired, but I don't want to have it in my ship anymore. (Anyone

interested in it?)



On the other end of the "robustness scale" are the surplus attitude

indicators. I bought a unit for scrap price from Ebay, and started

experimenting. The problem is that these units need 3 phase 115 Volt AC

400Hz, making them very unpopular (but also very affordable). Some

people built inverters, but with the three required transformers they

used to weigh as much as the instrument itself.



I decided to design and build a switching power supply myself. After

some testing and burning up some components, I now have something that

works, weighing less than 60 grams (2 oz), (excluding its housing), very

small, and efficient with electricity. (And powerfull, with just 12 Volt

input it can feed a normal 40 Watt houshold light bulb without problems).



I connected it to my Ebay-scrap-gyro from the 60's, and to my delight

the instrument started up right away. Low noise, and the horizon bar

erects and stabilises precisely where it needs to be. I suspect that

this unit has seen some more serious "mishandling" than my new Falcon

gyro, but despites it sounds and appears like it can service for many

more years to come.



Apart from having an affordable attitude indicator, for me it has some

additional value to have something in front of me that once serviced a

DC-3 or a fighter in the vietnam war, at least more sentimental value

than something that was made in China.



If anyone else is interested in using 3-phase, 115V AC 400hz attitude

indicators (or other instruments), I can see if I can make a few more of

these inverters, or assemble a components package for one who wants to

try to build it himself.



And just to be sure: I am aware of the existence of glass panels with

"attitude indicators" built in.  Telling me that this is a better

solution is the same as me telling you that you'd better just buy a nice

factory airplane instead of building your own.  I just love to fiddle

with all these instruments and electronics and I see less fun in

connecting a single huge screen that "has it all".



-- 

Frans Veldman

g-iani(at)ntlworld.com
Guest

Posted: Mon Mar 09, 2009 11:06 am Post subject: 3 phase 115V AC 400Hz light weight power supply

Frans



Did you think about the TruTrak Pilot 1 (or 2).  This would do what you want

and of course you could have autopilot if you want to spend the additional

$1000 per servo.  Mine has been reliable.



Ian Rickard G-IANI XS Trigear, 200 hours

Europa Club Mods Rep (Trigear)

e-mail mods(at)europaclub.org.uk   

   or direct g-iani(at)ntlworld.com

rparigor(at)suffolk.lib.n
Guest

Posted: Mon Mar 09, 2009 11:18 am Post subject: 3 phase 115V AC 400Hz light weight power supply

Hi Frans 

Sounds like great fun making a cheap 400MHz attitude indicator work on Europa power.Just a word of caution, might be worth it to have instrument gone over and rebuilt.I owned a 1948 Cessna 170 with a venturi driven gyro that worked OK as long as you had flying speed for 19 years. There was only one time I needed that instrument, taking off from Lebnon NH at night with a high overcast. It was the blackest night I ever flew in. At 200 feet my gyro said I was about to turn upside down. I knew my aeroplane, it was trimmed and let go of the controls. It was about 35 F and the bearings in the gyro descided to slightly bind up at that precise moment.I took it apart and adjusted and burnished the bearings with limited sucess. It needed new bushngs and shaft and tip bearings.If your unit has gyro bushings/bearings anything like mine did, replace them all or have them refinished. It wasn't all that expensive considering.Ron Parigoris (Parigoris(at)paardnatuurlijk.nl)   [quote][b]

frans(at)paardnatuurlijk.
Guest

Posted: Mon Mar 09, 2009 11:49 am Post subject: 3 phase 115V AC 400Hz light weight power supply

G-IANI wrote:



 	  Quote: 	
		   Did you think about the TruTrak Pilot 1 (or 2).


	


We did, for a long time. But we rejected it finally because it is not a

real gyro (if I remember correctly it would show wings level while you

are not flying coordinated and with one wing low, and it has to rely on

the static port to indicate a pitch angle, reducing redundancy), and to

be honest, on the pictures it looks a bit like a toy (but I have never

seen one in real life) while it is still quite expensive.



As an autopilot I already have the trio avionics autopilot, and it

double duties as a (gravity based, GPS coupled) turn coordinator. That's

one of the reasons I want to have a real attitude indicator, one that is

independent from GPS, static port and other sensors/inputs that are

shared by other instruments.



This redundancy is probably overkill as I'm not intentionally going to

fly in IMC, but it eases my mind to know that with for instance a static

port blockage, not all my instruments will heartily agree with each

other that I'm really holding altitude, while I'm in fact plunging down.



We considered various options for a gyro-less setup, but every time we

found reasons to come back to the good old gyro.



-- 

Frans Veldman

fklein(at)orcasonline.com
Guest

Posted: Mon Mar 09, 2009 11:59 am Post subject: 3 phase 115V AC 400Hz light weight power supply

What's the catch with the solid state gyro listed at only $165 at Acft  

Spr.



	http://www.aircraftspruce.com/catalog/inpages/1105706.php



Is this just a cheep toy or truly a gamechanger?



Fred

A194

frans(at)paardnatuurlijk.
Guest

Posted: Mon Mar 09, 2009 12:04 pm Post subject: 3 phase 115V AC 400Hz light weight power supply

rparigor(at)suffolk.lib.ny.us wrote:



 	  Quote: 	
		   Sounds like great fun making a cheap 400MHz attitude indicator work on

 Europa power.

 

 Just a word of caution, might be worth it to have instrument gone over

 and rebuilt.


	


That's what I intend to do anyway (if I can find a company still having

the parts and experience to do it properly). If the last owner has

dropped it, it is well possible that the instrument still works ok, but

the dents in the gears will make it fail rapidly.

But once it is overhauled, it is a top quality and very reliable instrument.



Thanks for sharing you thoughts.



-- 

Frans Veldman

DuaneFamly(at)aol.com
Guest

Posted: Mon Mar 09, 2009 12:05 pm Post subject: 3 phase 115V AC 400Hz light weight power supply

In a message dated 3/9/2009 1:00:27 P.M. Pacific Daylight Time,  fklein(at)orcasonline.com writes:

  	  Quote: 	
		  What's    the catch with the solid state gyro listed at only $165 at Acft     

Spr. 	


 

 Please note that it says "Sensors are Required" ......and the sensors are  $240 and $950. Add that to the price of the indicator and it puts it back into  the $$$ category.   

 Mike Duane  A207A

Redding, California

XS Conventional Gear

Jabiru  3300A

Sensenich R64Z N

Ground Adjustable  Prop



 Need a job? Find employment help in your area.

  [quote][b]

wdaniell(at)etb.net.co
Guest

Posted: Mon Mar 09, 2009 12:34 pm Post subject: 3 phase 115V AC 400Hz light weight power supply

http://www.pcflightsystems.com/  

   

I have one of these in my Zenith clone –  unless things go horribly wrong I certainly don’t intend fly in conditions where I might need it.  

   

Having said that it works well and provides a completely independent AI which runs off its own power.  

   

Will  

       

From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of Fred Klein

 Sent: Monday, March 09, 2009 15:02

 To: europa-list(at)matronics.com

 Subject: Fwd: 3 phase 115V AC 400Hz light weight power supply  

  

  

     

   

   	  Quote: 	
		    

What's the catch with the solid state gyro listed at only $165 at Acft Spr.

 

             http://www.aircraftspruce.com/catalog/inpages/1105706.php

 

 Is this just a cheep toy or truly a gamechanger?  	
  

     

Aha...the catch is a requirement for a $950 sensor package!  

    

   

    

...things to good to be true...rarely are...  

    



 

   

    

Sorry guys,  

    



 

   

    

Fred  

  [quote] [b]

budyerly(at)msn.com
Guest

Posted: Mon Mar 09, 2009 2:05 pm Post subject: 3 phase 115V AC 400Hz light weight power supply

<?xml:namespace prefix="v" /><?xml:namespace prefix="o" /><![endif]-->  Frans,

 The Tru Track ADI Pilot Attitude indicator is $1000 and comes with internal  compass and ball which is great.  Two instruments in one and backed by the  company.  Add a servo in the ADI Pilot I and you have autopilot or (wing  leveler) that interfaces with any Garmin product and most others.  

  

 You get what you pay for.  Time is money.

  

 Had a Falcon, had a Ray Allen, they all fail over time.  Tru Track is  solid state reliable, light and uses less power.

  

 I wish I was the dealer for them.  

  

 Bud Yerly

 Custom Flight Creations

 [quote]   ---

frans(at)paardnatuurlijk.
Guest

Posted: Mon Mar 09, 2009 3:02 pm Post subject: 3 phase 115V AC 400Hz light weight power supply

ALAN YERLY wrote:

 	  Quote: 	
		   Frans,

 The Tru Track ADI Pilot Attitude indicator is $1000 and comes with

 internal compass and ball which is great.


	


As far as I know it is not a compass but a GPS heading indicator. I

alread have a GPS, a compass is these days meant as a backup for the GPS

(in case of satellite failure). A "compass" based on GPS is worthless as

it offers almost no extra redundancy.

And as I mentioned before, solid state gyro's still have so much drift

that they need contineous compensation. Solid state gyro's are good in

detecting sudden changes, but they can't detect whether a situation

persists. So they need compensation from GPS ("hey we are still turning,

so we are most likely still banking) and from the static port ("pressure

is still decreasing, so let's continue to display a pitch-up, that would

probably be right"). These things are thus not showing the actual

situation, but a *derived* situation. Which will probably be right most

of the time, but offers you no additional information and is worthless

in a case of emergency: Loose your static port for some reason (icing?),

and you will loose your "pitch indicator" as well. Loose the GPS signal

for some reason, and the "compass" is gone too. Bank your airplane

without making a turn, and the indicator will try to convince you that

the wings are really, really level. (Don;t believe me? Try it next time

yourself. Of course you won't intentionally maintain heading with a

banked plane in VMC (cross controlled), but it could easily happen in

IMC, and that's why we have this attitude indicator in the first place,

right?). Problem with all this is lack of redundancy, and it is the

redundancy why I want to have an attitude indicator and compass in the

first place.



 	  Quote: 	
		   Add a servo in the ADI Pilot I and you have

 autopilot or (wing leveler) that interfaces with any Garmin product and

 most others. 


	


Here the same story. One of the reasons I have an auto-pilot is if I

inadvertently fly into IMC. If I suspect that my attitude indicator is

failing, I will let the autopilot take over. Or the other way around.

Unless.... the autopilot is linked to the same failing attitude

indicator. Loose that single one instrument, and all your options are gone.



 	  Quote: 	
		   Had a Falcon, had a Ray Allen, they all fail over time.  Tru Track is

 solid state reliable, light and uses less power.


	


It certainly has some advantages. But it is still not an equal

substitute for a real gyro.



-- 

Frans Veldman

kevann(at)gotsky.com
Guest

Posted: Mon Mar 09, 2009 3:50 pm Post subject: 3 phase 115V AC 400Hz light weight power supply

The trutrak has  built in magnetometer for  backup source of heading in case 

of GPS signal loss.

Kevin



---

paul.the.aviator(at)gmail
Guest

Posted: Mon Mar 09, 2009 7:35 pm Post subject: 3 phase 115V AC 400Hz light weight power supply

Hi Kevin & all,

  

 The Trutrack A/P that I have does have an internal magnetometer as well as taking a GPS track. Unfortunately the 2.25 ADI I have does not, it only has GPS track.  I installed the ADI as a back up to my glass,  it gives me GPS track, horizon and VSI.  Many people think due to the nature of the display that it is pitch, but it isn't.  The ADI is far from perfect, but I found that I could fly an approach with it under the hood, so I guess it was good enough.  If might be a different story in turbulence and pelting rain.

   

 With that said, given that I wanted some type of completely separate device to back my glass up it was the best choice available at the time.  Although it would have been cheaper I didn't really want a pair of glass panels with separate ADHS systems because I wanted to rule out the possibility of the same software bug occurring on both devices ( yes that is paranoia at is best ), I guess I have just written too much software in my past life to be that trusting.  Also, to give good redundancy I would have needed dual pitot static systems as well.

   

 In summary, I really like the approach that Frans has taken, it simple, and proven.  Sure, like everything else there are a bunch of things that could go wrong, but part of the exercise of engineering a system for our aircraft is to assume that something will fail and have something in your panel that will accommodate this failure.

 

 BTW, Frans, I thought of doing something similar but decided designing a three phase inverter was too hard, which is a very sad commentary on me given my past life in Electronic Engineering.  Kudos to you !

  

 Cheers,  Paul

  [quote][b]

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