RE: REFLECTOR: standby vacuum system

["Chuck Caldarale" <n828cl@ix.netcom.com>]

> From: owner-reflector@awpi.com [mailto:owner-reflector@awpi.com]On
> Behalf Of john daniel cowan
> Subject: REFLECTOR: standby vacuum system
>
> 1) Doesn't bleeding air into the intake manifold downstream of the
> carburetor screw up the mixture to at least some of the
> cylinders? lean them out unevenly?

There will be some unevenness, but since the SVS can only be used at part
throttle, it's not that bothersome. The amount of air is not large, compared
to the total volume going through the engine.

> 2) If it really doesn't, then why can't a bleed air (manifold
> suction/pressure differential) system be used all the time,
> with the normal suction regulator placed handily in line?

The SVS can't be used at full throttle, since there is very little
difference in pressure between manifold and ambient then. If you are at full
throttle when the vacuum pump goes, you have to pull it back a little to
drive the gyros.

It's not perfect by any means, but it is very economical insurance.

 - Chuck