My Sigma Tek attitude indicator is going South and after one failed
attempt to overhaul it I'm not excited to sent it elsewhere and try
again. It looks like I can buy a new TSO RC Allen for about $100 more
than overhauling my Sigma Tek. Is there any reason this isn't a no
brainer? Why would anyone overhaul a Sigma Tek when they could just
get a new unit? Is the Sigma Tek somehow a better unit?

-Robert

(Robert M. Gary) wrote in message >...
> My Sigma Tek attitude indicator is going South and after one failed
> attempt to overhaul it I'm not excited to sent it elsewhere and try
> again. It looks like I can buy a new TSO RC Allen for about $100 more
> than overhauling my Sigma Tek. Is there any reason this isn't a no
> brainer? Why would anyone overhaul a Sigma Tek when they could just
> get a new unit? Is the Sigma Tek somehow a better unit?

You didn't specify, but I assume you're dealing with a vacuum driven
unit. The RC Allen electric artificial horizons are lousy, but the
vacuum units are probably good. I had an RC Allen unit in my motor
glider and, engine on, it would start precessing in 5-10 minutes.
Admittedly, my engine (Rotax 914) operates at a much higher rpm
(4800-5800) than the unit is used to, so it may have been somewhat a
function of that.

Engine off, it was fine. Until ... it went south after a few years.
Overhauled it for over $1k -- a new one was a little under $2k -- and
that failed within six months. To be fair to RC Allen, I've heard that
most "low priced" (under $5k) electric AH's are not that good. If you
have a vacuum driven one, be glad!

BTW, other owners of the same motor glider have had similar comments
on the unit, so it isn't just my bad luck.

Martin