Today's Message Index:
----------------------
1. 07:39 AM - pitot system leaks ()
2. 08:09 AM - Re: pitot system leaks (Kevin Horton)
3. 08:51 AM - Re: pitot system leaks (Brian Alley)
Message 1
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| Subject: | pitot system leaks |
The vertical velocity indicator needs to be clamped or blocked. That
instrument has a =9Ccalibrated=9D leak in it. It=99s
the difference between the calibrated leak and pressure coming from the
static port as the plane ascends or descends that cause the needle to
deflect. As the plane continues to ascend or descent there will
continue to be a pressure differential. Once the plane levels off the
static pressure becomes constant. The calibrated leak will then slowly
match the static pressure and the needle will slowly return to zero. If
there is no calibrated leak, the VSI would act like an altimeter...
Joe Connell
Stewartville, MN
Time: 08:40:12 AM PST US
Subject: Re: RV-List: pitot system leaks
From: thomas sargent <sarg314@gmail.com>
I am still getting no where in testing my static system (or the static
system leaks horribly). Does the connection to the VSI have to be sealed
off before testing?
Message 2
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| Subject: | Re: pitot system leaks |
The "calibrated leak" in the VSI is internal to the VSI. It is not a leak between
the VSI and ambient pressure. The only way air can get into or out of a serviceable
VSI is at the connection to the static system.
There is no need to disconnect the VSI to do a static system leak check. I just
had my system checked by an avionics shop a few weeks ago. It passed with zero
leaks, without disconnecting anything.
Kevin Horton
On 2012-07-17, at 10:38 , <jconnell@fmwildblue.com> wrote:
> The vertical velocity indicator needs to be clamped or blocked. That instrument
has a calibrated leak in it. Its the difference between the calibrated leak
and pressure coming from the static port as the plane ascends or descends that
cause the needle to deflect. As the plane continues to ascend or descent
there will continue to be a pressure differential. Once the plane levels off
the static pressure becomes constant. The calibrated leak will then slowly match
the static pressure and the needle will slowly return to zero. If there is
no calibrated leak, the VSI would act like an altimeter...
>
> Joe Connell
> Stewartville, MN
>
> Time: 08:40:12 AM PST US
> Subject: Re: RV-List: pitot system leaks
> From: thomas sargent <sarg314@gmail.com>
>
> I am still getting no where in testing my static system (or the static
> system leaks horribly). Does the connection to the VSI have to be sealed
> off before testing?
>
Message 3
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| Subject: | Re: pitot system leaks |
Good point, static system instruments AI, Alt and VSI are closed systems. Otherwise
they would not work in a pressurized aircraft. There should not be anything
disconnect during calibration, but troubleshooting a problem is a different
situation!
Sent from my iPhone
Brian Alley
carbonfibercomposites.net
304-395-4932
On Jul 17, 2012, at 11:08 AM, Kevin Horton <khorton02@gmail.com> wrote:
>
> The "calibrated leak" in the VSI is internal to the VSI. It is not a leak between
the VSI and ambient pressure. The only way air can get into or out of a
serviceable VSI is at the connection to the static system.
>
> There is no need to disconnect the VSI to do a static system leak check. I just
had my system checked by an avionics shop a few weeks ago. It passed with
zero leaks, without disconnecting anything.
>
> Kevin Horton
>
>
>
> On 2012-07-17, at 10:38 , <jconnell@fmwildblue.com> wrote:
>
>> The vertical velocity indicator needs to be clamped or blocked. That instrument
has a calibrated leak in it. Its the difference between the calibrated leak
and pressure coming from the static port as the plane ascends or descends
that cause the needle to deflect. As the plane continues to ascend or descent
there will continue to be a pressure differential. Once the plane levels off
the static pressure becomes constant. The calibrated leak will then slowly match
the static pressure and the needle will slowly return to zero. If there
is no calibrated leak, the VSI would act like an altimeter...
>>
>> Joe Connell
>> Stewartville, MN
>>
>> Time: 08:40:12 AM PST US
>> Subject: Re: RV-List: pitot system leaks
>> From: thomas sargent <sarg314@gmail.com>
>>
>> I am still getting no where in testing my static system (or the static
>> system leaks horribly). Does the connection to the VSI have to be sealed
>> off before testing?
>>
>
>
>
>
>
>
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