Simviation Forums

In my various Motor cars fitted with normally aspirated petrol engines fitted with Carburettors, I often fitted a Vacuum Gauge directly connected/piped to the inlet manifold, to register manifold vacuum.

The Gauge dial was coloured Green, Yellow, and Red and the needle registered the Vacuum in these areas.

For economical cruising the needle should be kept in the green area, with the foot lifted off the throttle (greatest vacuum). Entering the red area indicated the throttle was being pushed down unnecessarily hard (breaking the vacuum), therefore; "wasting fuel!".... ...!

I wonder if there is a default Sim Vacuum Gauge which does the same job, for normally aspirated, carburettor, Piston engined aircraft?

Paul...G-BPLF...FS 2004...and a 1931 Brooklands Riley 9... 8-)...!

Yes.. it's the manifold pressure gauge... though it's background bitmap wont have colored arcs.. it just displays the pressure (or relative vacuum compared to atmospheric pressure)..

Yes.. it's the manifold pressure gauge... though it's background bitmap wont have colored arcs.. it just displays the pressure (or relative vacuum compared to atmospheric pressure)..

...of course!... ...!

Its the word "Pressure" which is/was fooling me...I was looking for a "Vacuum" Gauge. A "depression" in the Manifold!

Thanks for the reminder, Brett, I will find it useful to fit into simple aircraft which are not fitted with the gauge as standard...
It is a useful fitment to gain an idea of economical performance during flight.

Paul...G-BPLF...FS 2004....FS Nav....and a gentle tweak of the throttle... 8-)...!

P.S. Some aircraft, (Default Beech Baron 58), are fitted with a small "Suction Gauge", registering + - 5 on the dial. What does that indicate?

P.S. Some aircraft, (Default Beech Baron 58), are fitted with a small "Suction Gauge", registering + - 5 on the dial. What does that indicate?

That indicates the health of the system which keeps the flight-instrument gyros spinning, be it from an engine-driven vaccuum pump or an external venturi setup.

P.S. Some aircraft, (Default Beech Baron 58), are fitted with a small "Suction Gauge", registering + - 5 on the dial. What does that indicate?

That indicates the health of the system which keeps the flight-instrument gyros spinning, be it from an engine-driven vaccuum pump or an external venturi setup.

That's a biggie when flying by instruments. Many moons ago, I took off in a C172.. all was well until about 30 seconds into the climb. Earlier that day, a guy changed the battery, and failed to properly re-attach the vacuum hose .. it jiggled loose. It was a beautiful VFR, so no worries.. but when you lose the vacuum, you loose BOTH your heading indicator AND your attitude indicator.

Instrument traning prepares you for this.. and I can tell ya that flying in the clouds without those gauges is mind-bending. And it's why the third gyro-instrument (turn-coordinator), is electric. That, paired with the compass can keep you pointed in the right direction (and assure you that the wings are level).. but you gotta deduce your pitch by by your airspeed and power-setting, and back that up with a vertical speed/altitude.

While we're on the topic of of perilous failures... ponder what would happen if your pitot tube froze over completely, but the static port did not.

While we're on the topic of of perilous failures... ponder what would happen if your pitot tube froze over completely, but the static port did not.

Well first you have to figure out what instruments would be affected, in this case, your airspeed indicator.

Excellent !

Just the thought of that, scares the heck out of me. It also causes me to respect those with the intelligence to become a pilot even more.

Tempted but I'll let this one go  .

Just the thought of that, scares the heck out of me. It also causes me to respect those with the intelligence to become a pilot even more.

Tempted but I'll let this one go

[quote]Excellent !

Know what's almost worse than a partial panel ?

Flying in the clouds with "working" attitude indicator that has a roll indication that's off by 2 degrees... It short-circuits how put all the other gauges to use... even though you KNOW that it's off.

Know what's almost worse than a partial panel ?

Flying in the clouds with "working" attitude indicator that has a roll indication that's off by 2 degrees... It short-circuits how put all the other gauges to use... even though you KNOW that it's off.

Thats why I was always taught to carry post-it notes in your flightbag.  If you have an instrument giving funny readings and can't trust it, cover it up.  A lot easier to do partial panel without a malfunctioning instrument in the scan.  I even flew VFR once with a bad vacuum pump and the instruments still were throwing me off with a tumbling AI and spinning heading.