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-   -   Vacuum sys. driven instruments on helicopters? (https://www.pprune.org/rotorheads/640035-vacuum-sys-driven-instruments-helicopters.html)

hoistop 22nd Apr 2021 12:59

Vacuum sys. driven instruments on helicopters?
 
I am browsing thru some training material about helicopter systems - and I came across one that says there is no helicopter with vacuum system installed (used to drive gyro instruments)
I believe there is none installed on a turbine helicopter, but piston engine ones?
Anyone who can help me out with an example of standard fit vacuum system on a (piston engine) helicopter, that is currently in use in FAA/EASA world?
THX
hoistop

aa777888 22nd Apr 2021 13:06


Originally Posted by hoistop (Post 11032311)
I am browsing thru some training material about helicopter systems - and I came across one that says there is no helicopter with vacuum system installed (used to drive gyro instruments)
I believe there is none installed on a turbine helicopter, but piston engine ones?
Anyone who can help me out with an example of standard fit vacuum system on a (piston engine) helicopter, that is currently in use in FAA/EASA world?
THX
hoistop

All electric on the Robinson helicopters.

[email protected] 22nd Apr 2021 16:23

It would have to be a very old helicopter to have vacuum gyros - I haven't seen one in a military helicopter in 40 years.

RobertP 22nd Apr 2021 16:50

Vacuum Gyroscopic Instruments
 

Originally Posted by [email protected] (Post 11032390)
It would have to be a very old helicopter to have vacuum gyros - I haven't seen one in a military helicopter in 40 years.

I remember the Brantly, Hiller and B47 and those that had gyroscopic instruments were all electric powered.

wrench1 22nd Apr 2021 18:18


Originally Posted by hoistop (Post 11032311)
I believe there is none installed on a turbine helicopter, but piston engine ones?

As mentioned, you'd have to go back years to find vac systems in helicopters, to include turbines. For example, there was one large GOM operator that installed vacuum systems in all their 206Bs up through the 80s, early 90s. Once the cost lowered, and in some cases the reliability of the electric gyros increased, operators went strictly electric. I think you'll be hard pressed to find a vac system in any current helicopter at least on this side since the FAA streamlined the approval process to replace vacuum systems with electric flight instruments. In some cases it can be done as a minor alteration with only a mechanic's sign off.

attitudepowertrim 22nd Apr 2021 19:10

I've started my flying career on Alouette III (SudAviation/Aerospatiale). It was a machine from late 60's. That version had engine vacuum instruments from what I remember, playing stabilization gyros - heading and attitude indicator.

Fareastdriver 22nd Apr 2021 19:30

The Bristol Sycamore had vacuum instruments. I can remember flying them fifty-six years ago and having to ignore the artificial horizon when transiting because of the acceleration errors. There was no way you could topple them: You were confirmed to be, or soon to be, dead if that happened.
You can see from this picture the characteristic slant of an artificial horizon with a lack of vacuum.

Edited to add. This picture appears to have an electrical T&S but I cannot remember what a vacuum T&S had on its face.

BRISTOL Sycamore Walkaround



https://cimg9.ibsrv.net/gimg/pprune....f58d7a152.jpeg

FH1100 Pilot 22nd Apr 2021 21:40

Have there ever been turn-and-slip indicators that were *not* electric? Every one I've ever seen was electric.

WRENCH1 is right. Well into the 1990's, I flew for that GOM operator (PHI) that had vacuum artificial horizons and directional gyros in their 206B's. My knee-jerk first reaction was that it was a really bad idea and couldn't understand why they did that. Then, about that time, I looked at the cost of replacing the vacuum instruments in my Cessna 150 with electric ones. Holy cow! I just stayed with the old vacuum gauges. And PHI had, what, a couple of hundred 206B's at one time...206B's that *NEVER* flew IFR? Yeah, I'd put vacuum gauges in them too if I were the DOM. In fact, I still would.

md 600 driver 22nd Apr 2021 22:07


Originally Posted by attitudepowertrim (Post 11032461)
I've started my flying career on Alouette III (SudAviation/Aerospatiale). It was a machine from late 60's. That version had engine vacuum instruments from what I remember, playing stabilization gyros - heading and attitude indicator.

alouette 2 also had vacuum

sycamore 22nd Apr 2021 22:16

The `Skeeter` had an AH and DG driven by an engine-driven vacuum pump.....with an electric T & S.....

Ascend Charlie 22nd Apr 2021 23:02

And these days you can get a full 2-screen glass set-up for the cost of an overhaul of your electric AI.

Dexus 23rd Apr 2021 03:35


Originally Posted by attitudepowertrim (Post 11032461)
I've started my flying career on Alouette III (SudAviation/Aerospatiale). It was a machine from late 60's. That version had engine vacuum instruments from what I remember, playing stabilization gyros - heading and attitude indicator.

and SA-315 Lama also, IIRC...


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