Is a Turn Coordinator an electric motor or powered by fan?

[kickinwing]

I have always read and been taught that a turn coordinator is usually
powered by electricity. Is the turn coordinator, in itself, an
electric motor? Or does an electric-powered fan supply the air to spin
the gyro?

Anybody have any insight for me? Thanks.

[Morgans]

"kickinwing" > wrote in message
oups.com...
> I have always read and been taught that a turn coordinator is usually
> powered by electricity. Is the turn coordinator, in itself, an
> electric motor? Or does an electric-powered fan supply the air to spin
> the gyro?
>
> Anybody have any insight for me? Thanks.

They are mostly electric, and turn the gyro, directly. There are also
backup vacuum sources, powered by electric, but they are rare in single
piston airplanes.

It is a way of making a little bit of backup, to keep your wings right side
up, when your vacuum pump packs it in while you are in IMC.
--
Jim in NC

[Robert M. Gary]

The turn coordinator is almost always a self contained electric unit.
The attitude indicator and DG are unsually powered by air produced by
an external "fan" (we call it a pump). It may blow or suck depending on
the plane but it makes no difference, the effect is air moving across
the instrument.

-Robert, CFI

[Ron Natalie]

Robert M. Gary wrote:
> The turn coordinator is almost always a self contained electric unit.
> The attitude indicator and DG are unsually powered by air produced by
> an external "fan" (we call it a pump). It may blow or suck depending on
> the plane but it makes no difference, the effect is air moving across
> the instrument.
>
The advantage a turn coordinator has is that the gyro within doesn't
need to be free in space. It's axis barely changes, which means
it's much easier to direct drive with an electric motor. It only
needs to register a slight precession force.

[Morgans]

"Ron Natalie" > wrote

> The advantage a turn coordinator has is that the gyro within doesn't
> need to be free in space. It's axis barely changes, which means
> it's much easier to direct drive with an electric motor. It only
> needs to register a slight precession force.

Interesting. I didn't realize that was the reason. I still have to ask.
Why are the damn things so much more expensive than their vacuum powered
brethren? An electric motor just should not cost that much more!
--
Jim in NC

[Tauno Voipio]

Morgans wrote:
> "Ron Natalie" > wrote
>
>
>>The advantage a turn coordinator has is that the gyro within doesn't
>>need to be free in space. It's axis barely changes, which means
>>it's much easier to direct drive with an electric motor. It only
>>needs to register a slight precession force.
>
>
> Interesting. I didn't realize that was the reason. I still have to ask.
> Why are the damn things so much more expensive than their vacuum powered
> brethren? An electric motor just should not cost that much more!

It's not a plain brushed electric motor - the brushes won't
stand for long in a gyro and you do not want the brush dust
inside the gyro.

The traditional way is to use a variable reluctance AC motor
and an inverter to drive it.

I've been told that there are also brushless DC motors
in the later models.

--

Tauno Voipio
tauno voipio (at) iki fi