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
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