Turn co-ordinator

On Wed, 26 Oct 2005 03:14:11 GMT, "Marc J. Zeitlin"
wrote:

Jon Kraus wrote:

So what you are saying is that a windmilling engine is going to
produce enough vacuum to run the gyros? I think not...

Since the vacuum pump on most of our engines (an O-360 in my plane -
something similar in your Mooney) are run by a gear on the engine, as
long as the engine is spinning, the pump will be spinning. When I do my
runup, I get 5" of vacuum at anything over 1500 RPM or so - certainly at
1700 RPM or above.

So, as long as my engine windmills at more than 1500 RPM, I'll have more
than enough vacuum to run my gyros. And it does - I've tried it.

Try it yourself if you think not.....


You think wrong, Jon. Even at idle, most vacuum pumps produce enough
differential to keep rotors spinning satisfactorily.

You think wrong Bill. At least on my Mooney at idle doesn't come close
to the vacuum gauge reading in the green. This is with a new dry pump
too. I still doubt that a windmilling engine will keep the gyros spooled
up enough to run the AI and DG. Just my .02. YMMV

Jon Kraus
'79 Mooney 201
4443H @ TYQ

Bill Zaleski wrote:


You think wrong, Jon. Even at idle, most vacuum pumps produce enough
differential to keep rotors spinning satisfactorily.

Jon Kraus wrote:

You think wrong Bill. At least on my Mooney at idle doesn't come close
to the vacuum gauge reading in the green. This is with a new dry pump
too. I still doubt that a windmilling engine will keep the gyros spooled
up enough to run the AI and DG. Just my .02. YMMV

Jon Kraus
'79 Mooney 201
4443H @ TYQ

Bill Zaleski wrote:


You think wrong, Jon. Even at idle, most vacuum pumps produce enough
differential to keep rotors spinning satisfactorily.



Same with the club Arrow I fly. It takes 1200 or so to get the vacuum
into the green.

Matt

I never said that you will get "green line "vacuum. I did say that
the gyro's will continue to work with the vacuum that you will have
with a windmilling engine. Go to 10K, windmill, and see that you still
have useable gyro's. Been there, done that, they still work.


On Tue, 01 Nov 2005 11:48:38 GMT, Jon Kraus
wrote:

You think wrong Bill. At least on my Mooney at idle doesn't come close
to the vacuum gauge reading in the green. This is with a new dry pump
too. I still doubt that a windmilling engine will keep the gyros spooled
up enough to run the AI and DG. Just my .02. YMMV

Jon Kraus
'79 Mooney 201
4443H @ TYQ

Bill Zaleski wrote:


You think wrong, Jon. Even at idle, most vacuum pumps produce enough
differential to keep rotors spinning satisfactorily.

On 11/1/2005 17:43, Bill Zaleski wrote:

I never said that you will get "green line "vacuum. I did say that
the gyro's will continue to work with the vacuum that you will have
with a windmilling engine. Go to 10K, windmill, and see that you still
have useable gyro's. Been there, done that, they still work.

How long did you windmill? After all, the gyros are going to
continue to spin for some time with no vacuum. The slower they go,
the more difficulty they're going to have.

Did you go for more than 5 or 10 minutes and verify that they were
still working acceptably?




On Tue, 01 Nov 2005 11:48:38 GMT, Jon Kraus
wrote:

You think wrong Bill. At least on my Mooney at idle doesn't come close
to the vacuum gauge reading in the green. This is with a new dry pump
too. I still doubt that a windmilling engine will keep the gyros spooled
up enough to run the AI and DG. Just my .02. YMMV

Jon Kraus
'79 Mooney 201
4443H @ TYQ

Bill Zaleski wrote:


You think wrong, Jon. Even at idle, most vacuum pumps produce enough
differential to keep rotors spinning satisfactorily.



--
Mark Hansen, PP-ASEL, Instrument Airplane
Sacramento, CA

Yup. Right to the ground from 10K' bout 800FPM

Bill Z. A&P I.A.

On Wed, 02 Nov 2005 07:46:24 -0800, Mark Hansen
wrote:

On 11/1/2005 17:43, Bill Zaleski wrote:

I never said that you will get "green line "vacuum. I did say that
the gyro's will continue to work with the vacuum that you will have
with a windmilling engine. Go to 10K, windmill, and see that you still
have useable gyro's. Been there, done that, they still work.

How long did you windmill? After all, the gyros are going to
continue to spin for some time with no vacuum. The slower they go,
the more difficulty they're going to have.

Did you go for more than 5 or 10 minutes and verify that they were
still working acceptably?




On Tue, 01 Nov 2005 11:48:38 GMT, Jon Kraus
wrote:

You think wrong Bill. At least on my Mooney at idle doesn't come close
to the vacuum gauge reading in the green. This is with a new dry pump
too. I still doubt that a windmilling engine will keep the gyros spooled
up enough to run the AI and DG. Just my .02. YMMV

Jon Kraus
'79 Mooney 201
4443H @ TYQ

Bill Zaleski wrote:


You think wrong, Jon. Even at idle, most vacuum pumps produce enough
differential to keep rotors spinning satisfactorily.

"Mark Hansen" wrote in message ...
On 11/1/2005 17:43, Bill Zaleski wrote:

I never said that you will get "green line "vacuum. I did say that
the gyro's will continue to work with the vacuum that you will have
with a windmilling engine. Go to 10K, windmill, and see that you still
have useable gyro's. Been there, done that, they still work.

How long did you windmill? After all, the gyros are going to
continue to spin for some time with no vacuum. The slower they go,
the more difficulty they're going to have.

Did you go for more than 5 or 10 minutes and verify that they were
still working acceptably?


My gyros spin up from stopped to a usable state while my engines idle after startup.
Don't yours?

On 11/2/2005 08:33, John R. Copeland wrote:

"Mark Hansen" wrote in message ...
On 11/1/2005 17:43, Bill Zaleski wrote:

I never said that you will get "green line "vacuum. I did say that
the gyro's will continue to work with the vacuum that you will have
with a windmilling engine. Go to 10K, windmill, and see that you still
have useable gyro's. Been there, done that, they still work.

How long did you windmill? After all, the gyros are going to
continue to spin for some time with no vacuum. The slower they go,
the more difficulty they're going to have.

Did you go for more than 5 or 10 minutes and verify that they were
still working acceptably?


My gyros spin up from stopped to a usable state while my engines idle after startup.
Don't yours?


What is usable? The AI usually doesn't straighten-up 100% until after
I do my static run-up.

However, the real sign is the vacuum gage. It reads below the green while
idling. Now, the gyros are still spinning even while the vacuum is not
in the green - but I wouldn't want to bet my life on them while in IMC
conditions ... I may have to, but I wouldn't assume they are working 100%
while the vacuum is below the green.


--
Mark Hansen, PP-ASEL, Instrument Airplane
Sacramento, CA

"Mark Hansen" wrote in message ...
On 11/2/2005 08:33, John R. Copeland wrote:

"Mark Hansen" wrote in message ...
On 11/1/2005 17:43, Bill Zaleski wrote:

I never said that you will get "green line "vacuum. I did say that
the gyro's will continue to work with the vacuum that you will have
with a windmilling engine. Go to 10K, windmill, and see that you still
have useable gyro's. Been there, done that, they still work.

How long did you windmill? After all, the gyros are going to
continue to spin for some time with no vacuum. The slower they go,
the more difficulty they're going to have.

Did you go for more than 5 or 10 minutes and verify that they were
still working acceptably?


My gyros spin up from stopped to a usable state while my engines idle after startup.
Don't yours?


What is usable? The AI usually doesn't straighten-up 100% until after
I do my static run-up.

However, the real sign is the vacuum gage. It reads below the green while
idling. Now, the gyros are still spinning even while the vacuum is not
in the green - but I wouldn't want to bet my life on them while in IMC
conditions ... I may have to, but I wouldn't assume they are working 100%
while the vacuum is below the green.


Roger that.
Do you have any possibility of changing to a higher-capacity vacuum pump?
(I assume your instrument filters aren't clogged, of course.)
I show 5 inches Hg of vacuum at engine idle in my airplane.

Mark Hansen wrote:


What is usable? The AI usually doesn't straighten-up 100% until after
I do my static run-up.

Probably not the run-up but the elapsed time. It takes on the order of
ten minutes for the gyros to stableize.


However, the real sign is the vacuum gage. It reads below the green while
idling.

Fix your pump.