Q 152

Is the turn and bank indicator only avaible as electrical instrument or
allso as suction instrument
willy

Way back when dinosaurs walked the earth, we had vacuum instruments that got
their "power" from venturi tubes. They looked like an ice cream cone facing
forward with a pickoff tube connecting the narrow end to the instruments.
Only the really fancy aircraft had engine-driven vacuum pumps. I really
wonder if such things are in use anywhere today...gliders?

Bob Gardner

"Euromotors" <euromotors@village.uunet.be> wrote in message
news:4165ae43$0$44079$5fc3050@dreader2.news.tiscal i.nl...
> Is the turn and bank indicator only avaible as electrical instrument or
> allso as suction instrument
> willy
>
>

"Bob Gardner" <bobmrg@> wrote in message
news:Z-GdnX-865I3KPjcRVn-pQ@...
> Way back when dinosaurs walked the earth, we had vacuum instruments that
got
> their "power" from venturi tubes. They looked like an ice cream cone
facing
> forward with a pickoff tube connecting the narrow end to the instruments.
> Only the really fancy aircraft had engine-driven vacuum pumps. I really
> wonder if such things are in use anywhere today...gliders?

Are you asking about venturis? If so, thousands of aircraft still have
them.


>
> Bob Gardner
>
> "Euromotors" <euromotors@village.uunet.be> wrote in message
> news:4165ae43$0$44079$5fc3050@dreader2.news.tiscal i.nl...
> > Is the turn and bank indicator only avaible as electrical instrument
or
> > allso as suction instrument
> > willy
> >
> >
>
>

The turn and bank indicator (like any other gyro instrument) are
available that can be powered from either electric or vacuum power. The
reason most small planes have them electric powered is so you have some
kind of attitude indicating capability (even if it's limited) should the
vacuum pump fail. You won't usually lose both electric power and vacuum
pump (which works off the engine) at the same time.

Newer instruments don't have a mechanical gyro at all, but a solid state
gyro. These are electronic and use a self centering inertia strain
sensor that give you the capability of a gyro without all the noise and
worn bearings.

You will find different combinations of these instruments in different
planes. Some aircraft are purely vacuum powered (no electrical system)
and might use a suction turn indicator. Others have no vacuum system and
are so dependent on electrical power they use exclusively electric or
electronic instruments. Such aircraft have multiple electrical systems
for redundancy.

Suction only systems are not just for dinasours, you will still find
such systems in lighter duty experimentals and even some ultralights
(sport pilot stuff).

Hope this helps...
-ahc-


Euromotors wrote:

> Is the turn and bank indicator only avaible as electrical instrument or
> allso as suction instrument
> willy
>
>