Morgans wrote:
"jmk" wrote

Worst case for most of those RC gyros (designed for RC helicopters,
etc.) is about 3 degrees per second.

Wow, I didn't know that they sucked THAT bad! g

Remember... that's *worst case* according to their spec.

They are based on the cheap MEMS solid state chips that are so
incredibly cheap because most modern cars have a anywhere from 4 to 20
of them. Usually a couple on each wheel, and another on each wheel
that steers. They compensate for the GPS shadowing that is otherwise
unacceptable on a moving map when driving in the city or under trees
(especially if it's been raining). They are only expected (in this
application) to show the basic turn direction for a couple of seconds
until the GPS can "catch up."

There more critical function is anti-skid, ride quality, and braking
functions - again, while the application may be critical, the exact
numbers aren't.

In a reasonably constant temperature environment, with some minimal
compensation from a processor, they should do MUCH better.

However, for something like replacing the AH, they are a LONG way from
being ready for prime time - at least without major enhancement. [We
did some rather fascinating experiments with "shake and bake" when the
first uncertified units came onto the homebuilt market. Including
putting one on a battery operated record player platter and setting the
whole thing (instrumented) in a refrigerator! After a few minutes it
showed the plane flying straight and level (DG function) as it went
round and round and round... G]

Interestingly enough, they are being used as part of the replacement
gyro for the King and Sandel HSI. The catch - like the automotive
moving map in cars, they are being updated every few seconds by the
flux gate.