Leak testing my new ride

[[email protected]]

As a result of some pretty funky vario behavior at the recent Bermuda High regional contest, I decided to leak test my new (to me) V2cx ship. I took as my guideline the excellent 2000 (updated in 2008) article on this subject by Mike Borgelt of Borgelt Instruments (http://www.borgeltinstruments.com/Leaks.pdf). Thanks Mike!

My ship has a Borgelt B40 vario and a SN10B vario. A single TE line comes out of the tubing channel under the instrument panel, and is T'd there to both the B40 and the SN10, with about 5" tubing runs from the T to the SN10/B40 (i.e. about 10" of tubing run between the two). Pretty much the same geometry with the Pitot and Static lines - single line coming into the instrument panel area, and short connectors to the instruments. I have read that at least the TE line should be T'd well away from the instrument (one article recommended T'in the TE line under the pilot's seat so that the instrument-to-instrument length is 10-15'), so I'm a little concerned about that part. I've also read that the SN10B is a 'flow' instrument (don't know about the B40). Any comments on this?

To conduct the tests, I first tested the ASI and verified that it was working properly. Then I used it to measure leakage rates for the Pitot, Static, and TE lines.

Pitot: I attached a long length of tubing to the tailfin-mounted pitot port, and carefully pressurized the line to 95KT indicated. Then I clamped the line with a hemostat, and watched for decreasing airspeed. It took approximately 4 minutes to go from the initial 95KT to 90Kt.

Static: I taped off all 4 static ports, and then replaced the transponder's static line with my test line, connected to a 60ml syringe. I slowly pulled negative pressure until the ASI read about 100KT, and clamped the line off with the hemostat. In this test, it took about 3 minutes to decrease 5Kt, from 100KT to 95KT.

TE: For this test, I replaced the ASI's static line with the TE line from my SN10, leaving the B40 still connected to the TE system. Then I attached a long length of tubing to the tailfin-mounted TE port, and carefully pulled negative pressure to achieve 120KTIAS. Then I clamped the hose as before with the hemostat. In this test, it only took about 30 seconds for the ASI to decrease 10KT to 110KT, and another 30 seconds to decrease to 100KT.

Leak Rates:

Pitot: 5Kt in 4 minutes = 1.25Kt/min
Static: 5Kt in 3 minutes = 1.33Kt/min
TE: 5Kt in 0.5 minutes = 10Kt/min (almost an order of magnitude higher!)

Any thoughts and/or advice on whether these leak rates are normal or excessive, and how to proceed from here would be appreciated.

TIA,

Frank (TA)

[Richard[_9_]]

On Sunday, May 11, 2014 3:58:10 PM UTC-7, wrote:
> As a result of some pretty funky vario behavior at the recent Bermuda High regional contest, I decided to leak test my new (to me) V2cx ship. I took as my guideline the excellent 2000 (updated in 2008) article on this subject by Mike Borgelt of Borgelt Instruments (http://www.borgeltinstruments.com/Leaks.pdf). Thanks Mike!
>
>
>
> My ship has a Borgelt B40 vario and a SN10B vario. A single TE line comes out of the tubing channel under the instrument panel, and is T'd there to both the B40 and the SN10, with about 5" tubing runs from the T to the SN10/B40 (i.e. about 10" of tubing run between the two). Pretty much the same geometry with the Pitot and Static lines - single line coming into the instrument panel area, and short connectors to the instruments. I have read that at least the TE line should be T'd well away from the instrument (one article recommended T'in the TE line under the pilot's seat so that the instrument-to-instrument length is 10-15'), so I'm a little concerned about that part. I've also read that the SN10B is a 'flow' instrument (don't know about the B40). Any comments on this?
>
>
>
> To conduct the tests, I first tested the ASI and verified that it was working properly. Then I used it to measure leakage rates for the Pitot, Static, and TE lines.
>
>
>
> Pitot: I attached a long length of tubing to the tailfin-mounted pitot port, and carefully pressurized the line to 95KT indicated. Then I clamped the line with a hemostat, and watched for decreasing airspeed. It took approximately 4 minutes to go from the initial 95KT to 90Kt.
>
>
>
> Static: I taped off all 4 static ports, and then replaced the transponder's static line with my test line, connected to a 60ml syringe. I slowly pulled negative pressure until the ASI read about 100KT, and clamped the line off with the hemostat. In this test, it took about 3 minutes to decrease 5Kt, from 100KT to 95KT.
>
>
>
> TE: For this test, I replaced the ASI's static line with the TE line from my SN10, leaving the B40 still connected to the TE system. Then I attached a long length of tubing to the tailfin-mounted TE port, and carefully pulled negative pressure to achieve 120KTIAS. Then I clamped the hose as before with the hemostat. In this test, it only took about 30 seconds for the ASI to decrease 10KT to 110KT, and another 30 seconds to decrease to 100KT.
>
>
>
> Leak Rates:
>
>
>
> Pitot: 5Kt in 4 minutes = 1.25Kt/min
>
> Static: 5Kt in 3 minutes = 1.33Kt/min
>
> TE: 5Kt in 0.5 minutes = 10Kt/min (almost an order of magnitude higher!)
>
>
>
> Any thoughts and/or advice on whether these leak rates are normal or excessive, and how to proceed from here would be appreciated.
>
>
>
> TIA,
>
>
>
> Frank (TA)

The only problems you may have is the TE line it should hold pressure forever or at least a long time lets say hours. Don't use a varo use an A/S indicator. Pressurize to 80 kts. To make a complete check install the TE probe and tape the holes. T the TE and A/S indicator in the front panel to a syringe and pressurize to 80 knts. It should not leak at all. If it leaks you have a problem. The B40 is a pressure sensor vario not a flow vario.

Richard
www.craggyaero.com

[Hartley Falbaum[_2_]]

On Sunday, May 11, 2014 6:58:10 PM UTC-4, wrote:
> As a result of some pretty funky vario behavior at the recent Bermuda High regional contest, I decided to leak test my new (to me) V2cx ship. I took as my guideline the excellent 2000 (updated in 2008) article on this subject by Mike Borgelt of Borgelt Instruments (http://www.borgeltinstruments.com/Leaks.pdf). Thanks Mike!
>
>
>
> My ship has a Borgelt B40 vario and a SN10B vario. A single TE line comes out of the tubing channel under the instrument panel, and is T'd there to both the B40 and the SN10, with about 5" tubing runs from the T to the SN10/B40 (i.e. about 10" of tubing run between the two). Pretty much the same geometry with the Pitot and Static lines - single line coming into the instrument panel area, and short connectors to the instruments. I have read that at least the TE line should be T'd well away from the instrument (one article recommended T'in the TE line under the pilot's seat so that the instrument-to-instrument length is 10-15'), so I'm a little concerned about that part. I've also read that the SN10B is a 'flow' instrument (don't know about the B40). Any comments on this?
>
>
>
> To conduct the tests, I first tested the ASI and verified that it was working properly. Then I used it to measure leakage rates for the Pitot, Static, and TE lines.
>
>
>
> Pitot: I attached a long length of tubing to the tailfin-mounted pitot port, and carefully pressurized the line to 95KT indicated. Then I clamped the line with a hemostat, and watched for decreasing airspeed. It took approximately 4 minutes to go from the initial 95KT to 90Kt.
>
>
>
> Static: I taped off all 4 static ports, and then replaced the transponder's static line with my test line, connected to a 60ml syringe. I slowly pulled negative pressure until the ASI read about 100KT, and clamped the line off with the hemostat. In this test, it took about 3 minutes to decrease 5Kt, from 100KT to 95KT.
>
>
>
> TE: For this test, I replaced the ASI's static line with the TE line from my SN10, leaving the B40 still connected to the TE system. Then I attached a long length of tubing to the tailfin-mounted TE port, and carefully pulled negative pressure to achieve 120KTIAS. Then I clamped the hose as before with the hemostat. In this test, it only took about 30 seconds for the ASI to decrease 10KT to 110KT, and another 30 seconds to decrease to 100KT.
>
>
>
> Leak Rates:
>
>
>
> Pitot: 5Kt in 4 minutes = 1.25Kt/min
>
> Static: 5Kt in 3 minutes = 1.33Kt/min
>
> TE: 5Kt in 0.5 minutes = 10Kt/min (almost an order of magnitude higher!)
>
>
>
> Any thoughts and/or advice on whether these leak rates are normal or excessive, and how to proceed from here would be appreciated.
>
>
>
> TIA,
>
>
>
> Frank (TA)

Separate the two various, and test each individually. Any connection is a source of leak, including the junction of instrument case and hose nipple. Wiggle test tells the tale.

[[email protected]]

Thanks for the replies. I found that the line to the Borgelt was loose at the 'T' connector. When I cut it back a bit and re-installed, the leak rate dropped considerably (to about the same as the pitot/static tests), but did not stop entirely. This leads me to suspect all the tubing (and maybe the 'T' connectors too), so I plan to replace them ASAP.


Frank (TA)


On Monday, May 12, 2014 7:42:22 AM UTC-4, Hartley Falbaum wrote:
> On Sunday, May 11, 2014 6:58:10 PM UTC-4, wrote:
>
> > As a result of some pretty funky vario behavior at the recent Bermuda High regional contest, I decided to leak test my new (to me) V2cx ship. I took as my guideline the excellent 2000 (updated in 2008) article on this subject by Mike Borgelt of Borgelt Instruments (http://www.borgeltinstruments.com/Leaks.pdf). Thanks Mike!
>
> >
>
> >
>
> >
>
> > My ship has a Borgelt B40 vario and a SN10B vario. A single TE line comes out of the tubing channel under the instrument panel, and is T'd there to both the B40 and the SN10, with about 5" tubing runs from the T to the SN10/B40 (i.e. about 10" of tubing run between the two). Pretty much the same geometry with the Pitot and Static lines - single line coming into the instrument panel area, and short connectors to the instruments. I have read that at least the TE line should be T'd well away from the instrument (one article recommended T'in the TE line under the pilot's seat so that the instrument-to-instrument length is 10-15'), so I'm a little concerned about that part. I've also read that the SN10B is a 'flow' instrument (don't know about the B40). Any comments on this?
>
> >
>
> >
>
> >
>
> > To conduct the tests, I first tested the ASI and verified that it was working properly. Then I used it to measure leakage rates for the Pitot, Static, and TE lines.
>
> >
>
> >
>
> >
>
> > Pitot: I attached a long length of tubing to the tailfin-mounted pitot port, and carefully pressurized the line to 95KT indicated. Then I clamped the line with a hemostat, and watched for decreasing airspeed. It took approximately 4 minutes to go from the initial 95KT to 90Kt.
>
> >
>
> >
>
> >
>
> > Static: I taped off all 4 static ports, and then replaced the transponder's static line with my test line, connected to a 60ml syringe. I slowly pulled negative pressure until the ASI read about 100KT, and clamped the line off with the hemostat. In this test, it took about 3 minutes to decrease 5Kt, from 100KT to 95KT.
>
> >
>
> >
>
> >
>
> > TE: For this test, I replaced the ASI's static line with the TE line from my SN10, leaving the B40 still connected to the TE system. Then I attached a long length of tubing to the tailfin-mounted TE port, and carefully pulled negative pressure to achieve 120KTIAS. Then I clamped the hose as before with the hemostat. In this test, it only took about 30 seconds for the ASI to decrease 10KT to 110KT, and another 30 seconds to decrease to 100KT.
>
> >
>
> >
>
> >
>
> > Leak Rates:
>
> >
>
> >
>
> >
>
> > Pitot: 5Kt in 4 minutes = 1.25Kt/min
>
> >
>
> > Static: 5Kt in 3 minutes = 1.33Kt/min
>
> >
>
> > TE: 5Kt in 0.5 minutes = 10Kt/min (almost an order of magnitude higher!)
>
> >
>
> >
>
> >
>
> > Any thoughts and/or advice on whether these leak rates are normal or excessive, and how to proceed from here would be appreciated.
>
> >
>
> >
>
> >
>
> > TIA,
>
> >
>
> >
>
> >
>
> > Frank (TA)
>
>
>
> Separate the two various, and test each individually. Any connection is a source of leak, including the junction of instrument case and hose nipple. Wiggle test tells the tale.

[Robert M]

On Sunday, May 11, 2014 4:58:10 PM UTC-6, wrote:
> As a result of some pretty funky vario behavior at the recent Bermuda High regional contest, I decided to leak test my new (to me) V2cx ship. I took as my guideline the excellent 2000 (updated in 2008) article on this subject by Mike Borgelt of Borgelt Instruments (http://www.borgeltinstruments.com/Leaks.pdf). Thanks Mike!
>
>
>
> My ship has a Borgelt B40 vario and a SN10B vario. A single TE line comes out of the tubing channel under the instrument panel, and is T'd there to both the B40 and the SN10, with about 5" tubing runs from the T to the SN10/B40 (i.e. about 10" of tubing run between the two). Pretty much the same geometry with the Pitot and Static lines - single line coming into the instrument panel area, and short connectors to the instruments. I have read that at least the TE line should be T'd well away from the instrument (one article recommended T'in the TE line under the pilot's seat so that the instrument-to-instrument length is 10-15'), so I'm a little concerned about that part. I've also read that the SN10B is a 'flow' instrument (don't know about the B40). Any comments on this?
>
>
>
> To conduct the tests, I first tested the ASI and verified that it was working properly. Then I used it to measure leakage rates for the Pitot, Static, and TE lines.
>
>
>
> Pitot: I attached a long length of tubing to the tailfin-mounted pitot port, and carefully pressurized the line to 95KT indicated. Then I clamped the line with a hemostat, and watched for decreasing airspeed. It took approximately 4 minutes to go from the initial 95KT to 90Kt.
>
>
>
> Static: I taped off all 4 static ports, and then replaced the transponder's static line with my test line, connected to a 60ml syringe. I slowly pulled negative pressure until the ASI read about 100KT, and clamped the line off with the hemostat. In this test, it took about 3 minutes to decrease 5Kt, from 100KT to 95KT.
>
>
>
> TE: For this test, I replaced the ASI's static line with the TE line from my SN10, leaving the B40 still connected to the TE system. Then I attached a long length of tubing to the tailfin-mounted TE port, and carefully pulled negative pressure to achieve 120KTIAS. Then I clamped the hose as before with the hemostat. In this test, it only took about 30 seconds for the ASI to decrease 10KT to 110KT, and another 30 seconds to decrease to 100KT.
>
>
>
> Leak Rates:
>
>
>
> Pitot: 5Kt in 4 minutes = 1.25Kt/min
>
> Static: 5Kt in 3 minutes = 1.33Kt/min
>
> TE: 5Kt in 0.5 minutes = 10Kt/min (almost an order of magnitude higher!)
>
>
>
> Any thoughts and/or advice on whether these leak rates are normal or excessive, and how to proceed from here would be appreciated.
>
>
>
> TIA,
>
>
>
> Frank (TA)

[Robert M]

On Monday, May 12, 2014 7:05:20 AM UTC-6, wrote:
> This leads me to suspect all the tubing (and maybe the 'T' connectors too), so I plan to replace them ASAP.
>
>>Do not use the clear poly tubing from your local hardware store. It loses its flexibility over a short period of time and that can cause leaks.

But quality tubing from one of the glider suppliers. I know that Wings and Wheels stocks this tubing but other glider outlets do also.

Robert Mudd