Re: [Aus-soaring] Fwd: Re: Fun with Form 2 Inspections and paperwork

[Ross McLean]

That incident is almost a qualifier for the Darwin Awards!! (see:
http://www.darwinawards.com/)  

ROSS

 


_ 

 


At 11:12 PM 4/25/2016, you wrote:



One should be careful on this matter.  Please think again.  I seem to
recollect a case in America with an FRP sailplane years ago where the vents
on the wing surface to the water tanks were taped over and a flight in wave
conditions was undertaken.  Also the tank outlets were closed and so the
tanks were thus sealed . This did not present any problems on ascent to some
serious altitude (something like 15 to 20,000 feet).  On ascent the excess
higher pressure in the tanks caused the tape at the vents to lift sufficient
to bleed the air out of the tanks via the vents progressively.  The problem
came on long descent from high altitude where the air pressure differential
at the vents pushed the tape hard to the surface and prevented partly or
wholly the air flowing back into the tank.  The result was that towards the
end of the descent both wing tanks, leading edge to spar, collapsed due to
the large and crushing pressure differential.

Many sailplanes have wing undersurface tank outlets where a tapered plug
sits into a tapered seat built into the wing shell. Higher interior air
pressure as compared to exterior pressure, such as in the long descent
situation above, will push the plug into the taper improving the seal.

There is a good argument for duplicated vents to each tank with the vent
outlets in different locations, given that a vent may become blocked say due
to mud wasps.

The vents are there for a reason, because venting unwanted pressure
differential is good.

Regards, Roger Druce

On 23/04/2016 8:15 PM, Justin Couch wrote:



On 23/04/2016 2:30 AM, Jim Staniforth wrote:



Can a pilot tape over the dump holes to reduce noise, or is that a
breach of contract?


I'm pretty sure some tape over the holes would be fine - plenty of gliders
with underwing dump valves have a little mylar or rubber flap over them for
fairing purposes - our club DG1000 does. I've seen tape plenty of times over
the Jantar dump outlet too for the same reason.

I can't say for 100% coverage, but the flight manuals of gliders that I've
read state that the tanks should be left open if flying without water.
Obvious reason for this is to prevent the pressure change splitting the wing
open at altitude. A bit of tape won't hold much pressure behind it so the
manufacturers instructions are still being obeyed anyway.


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Re: [Aus-soaring] Fwd: Re: Fun with Form 2 Inspections and paperwork

[Mike Borgelt]

Seems to me lock wiring the ballast dump system might be an 
unapproved mod. unless the manufacturer has scheme to do it such as 
where exactly and how it is done with the correct diameter 
lockwire,0.025" or 0.032"?


We can play the stupid trivia game all day. All for lack of  TRUST 
that a pilot will obey a placard. You are forced to trust him or her 
to obey the other  placards.


BTW successful cultures tend to be high trust cultures. You don't 
want to live in a low trust culture (aka the third world). Why the 
authorities are hell bent on making this a low trust culture (or 
defending its values) is beyond me.


I guess checking the dump vents are clear ought to be part of the DI.

There's only one vent into each fuel tank on the BD-4 and they aren't 
interconnected. How many powered aircraft have two in the light aircraft field?


I agree it would be a good idea there too.

Mike






At 11:12 PM 4/25/2016, you wrote:
One should be careful on this matter.  Please think again.  I seem 
to recollect a case in America with an FRP sailplane years ago where 
the vents on the wing surface to the water tanks were taped over and 
a flight in wave conditions was undertaken.  Also the tank outlets 
were closed and so the tanks were thus sealed . This did not present 
any problems on ascent to some serious altitude (something like 15 
to 20,000 feet).  On ascent the excess higher pressure in the tanks 
caused the tape at the vents to lift sufficient to bleed the air out 
of the tanks via the vents progressively.  The problem came on long 
descent from high altitude where the air pressure differential at 
the vents pushed the tape hard to the surface and prevented partly 
or wholly the air flowing back into the tank.  The result was that 
towards the end of the descent both wing tanks, leading edge to 
spar, collapsed due to the large and crushing pressure differential.


Many sailplanes have wing undersurface tank outlets where a tapered 
plug sits into a tapered seat built into the wing shell. Higher 
interior air pressure as compared to exterior pressure, such as in 
the long descent situation above, will push the plug into the taper 
improving the seal.


There is a good argument for duplicated vents to each tank with the 
vent outlets in different locations, given that a vent may become 
blocked say due to mud wasps.


The vents are there for a reason, because venting unwanted pressure 
differential is good.


Regards, Roger Druce

On 23/04/2016 8:15 PM, Justin Couch wrote:

On 23/04/2016 2:30 AM, Jim Staniforth wrote:

Can a pilot tape over the dump holes to reduce noise, or is that a
breach of contract?


I'm pretty sure some tape over the holes would be fine - plenty of 
gliders with underwing dump valves have a little mylar or rubber 
flap over them for fairing purposes - our club DG1000 does. I've 
seen tape plenty of times over the Jantar dump outlet too for the same reason.


I can't say for 100% coverage, but the flight manuals of gliders 
that I've read state that the tanks should be left open if flying 
without water. Obvious reason for this is to prevent the pressure 
change splitting the wing open at altitude. A bit of tape won't 
hold much pressure behind it so the manufacturers instructions are 
still being obeyed anyway.


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instrumentation since 1978

www.borgeltinstruments.com
tel:   07 4635 5784 overseas: int+61-7-4635 5784
mob: 042835 5784:  int+61-42835 5784
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Re: [Aus-soaring] Fwd: Re: Fun with Form 2 Inspections and paperwork

[Roger . D]

One should be careful on this matter.  Please think again.  I seem to 
recollect a case in America with an FRP sailplane years ago where the 
vents on the wing surface to the water tanks were taped over and a 
flight in wave conditions was undertaken.  Also the tank outlets were 
closed and so the tanks were thus sealed . This did not present any 
problems on ascent to some serious altitude (something like 15 to 20,000 
feet).  On ascent the excess higher pressure in the tanks caused the 
tape at the vents to lift sufficient to bleed the air out of the tanks 
via the vents progressively.  The problem came on long descent from high 
altitude where the air pressure differential at the vents pushed the 
tape hard to the surface and prevented partly or wholly the air flowing 
back into the tank.  The result was that towards the end of the descent 
both wing tanks, leading edge to spar, collapsed due to the large and 
crushing pressure differential.


Many sailplanes have wing undersurface tank outlets where a tapered plug 
sits into a tapered seat built into the wing shell. Higher interior air 
pressure as compared to exterior pressure, such as in the long descent 
situation above, will push the plug into the taper improving the seal.


There is a good argument for duplicated vents to each tank with the vent 
outlets in different locations, given that a vent may become blocked say 
due to mud wasps.


The vents are there for a reason, because venting unwanted pressure 
differential is good.


Regards, Roger Druce

On 23/04/2016 8:15 PM, Justin Couch wrote:

On 23/04/2016 2:30 AM, Jim Staniforth wrote:

Can a pilot tape over the dump holes to reduce noise, or is that a
breach of contract?


I'm pretty sure some tape over the holes would be fine - plenty of 
gliders with underwing dump valves have a little mylar or rubber flap 
over them for fairing purposes - our club DG1000 does. I've seen tape 
plenty of times over the Jantar dump outlet too for the same reason.


I can't say for 100% coverage, but the flight manuals of gliders that 
I've read state that the tanks should be left open if flying without 
water. Obvious reason for this is to prevent the pressure change 
splitting the wing open at altitude. A bit of tape won't hold much 
pressure behind it so the manufacturers instructions are still being 
obeyed anyway.




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Re: [Aus-soaring] Fwd: Re: Fun with Form 2 Inspections and paperwork

[Justin Couch]

On 24/04/2016 1:06 AM, Ross McLean wrote:

I am pretty sure that it is not actually possible to do that.  You may not
be aware that there is a vent built into the wing to allow air to enter the
tank as the water is dumping. It is not a valve, it is an open vent.  If the
ballast tank is empty and there is a change of pressure in the tank then air
will enter or exit via that same vent should the dump valve be closed.


Yeah, sorry. Brain fade. I keep having to remember where the damn things 
are located each time I do a tank test to tape them up. Mostly I work on 
gliders with either no water at all or bags rather than integral tanks.


--
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Java 3D Graphics Informationhttp://www.j3d.org/
LinkedIn http://au.linkedin.com/in/justincouch/
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---
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 Turn it or move it, and a new set of arrangements appears... is it
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 distinguish, recognise and appreciate? Is it one light with many
 frames or one frame for many lights?"  -Subcomandante Marcos
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Re: [Aus-soaring] Fwd: Re: Fun with Form 2 Inspections and paperwork

[Ross McLean]

Hi Justin

Just on your comment :

"... that the tanks should be left open if flying without water. Obvious
reason for this is to prevent the pressure change splitting the wing open at
altitude"

 

I am pretty sure that it is not actually possible to do that.  You may not
be aware that there is a vent built into the wing to allow air to enter the
tank as the water is dumping. It is not a valve, it is an open vent.  If the
ballast tank is empty and there is a change of pressure in the tank then air
will enter or exit via that same vent should the dump valve be closed.

ROSS


_ 

 

-Original Message-
From: Aus-soaring [mailto:aus-soaring-boun...@lists.base64.com.au] On Behalf
Of Justin Couch
Sent: Saturday, 23 April 2016 8:15 PM
To: aus-soaring@lists.base64.com.au
Subject: Re: [Aus-soaring] Fwd: Re: Fun with Form 2 Inspections and
paperwork

 

On 23/04/2016 2:30 AM, Jim Staniforth wrote:

> Can a pilot tape over the dump holes to reduce noise, or is that a 

> breach of contract?

 

I'm pretty sure some tape over the holes would be fine - plenty of gliders
with underwing dump valves have a little mylar or rubber flap over them for
fairing purposes - our club DG1000 does. I've seen tape plenty of times over
the Jantar dump outlet too for the same reason.

 

I can't say for 100% coverage, but the flight manuals of gliders that I've
read state that the tanks should be left open if flying without water.
Obvious reason for this is to prevent the pressure change splitting the wing
open at altitude. A bit of tape won't hold much pressure behind it so the
manufacturers instructions are still being obeyed anyway.

 

-- 

Justin Couch  <http://www.vlc.com.au/>
http://www.vlc.com.au/

Java 3D Graphics Information <http://www.j3d.org/>
http://www.j3d.org/

LinkedIn  <http://au.linkedin.com/in/justincouch/>
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---

"Look through the lens, and the light breaks down into many lights.

  Turn it or move it, and a new set of arrangements appears... is it

  a single light or many lights, lights that one must know how to

  distinguish, recognise and appreciate? Is it one light with many

  frames or one frame for many lights?"  -Subcomandante Marcos

---

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Re: [Aus-soaring] Fwd: Re: Fun with Form 2 Inspections and paperwork

[Justin Couch]

On 23/04/2016 2:30 AM, Jim Staniforth wrote:

Can a pilot tape over the dump holes to reduce noise, or is that a
breach of contract?


I'm pretty sure some tape over the holes would be fine - plenty of 
gliders with underwing dump valves have a little mylar or rubber flap 
over them for fairing purposes - our club DG1000 does. I've seen tape 
plenty of times over the Jantar dump outlet too for the same reason.


I can't say for 100% coverage, but the flight manuals of gliders that 
I've read state that the tanks should be left open if flying without 
water. Obvious reason for this is to prevent the pressure change 
splitting the wing open at altitude. A bit of tape won't hold much 
pressure behind it so the manufacturers instructions are still being 
obeyed anyway.


--
Justin Couch http://www.vlc.com.au/
Java 3D Graphics Informationhttp://www.j3d.org/
LinkedIn http://au.linkedin.com/in/justincouch/
G+   WetMorgoth
---
"Look through the lens, and the light breaks down into many lights.
 Turn it or move it, and a new set of arrangements appears... is it
 a single light or many lights, lights that one must know how to
 distinguish, recognise and appreciate? Is it one light with many
 frames or one frame for many lights?"  -Subcomandante Marcos
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Re: [Aus-soaring] Fwd: Re: Fun with Form 2 Inspections and paperwork

[Jim Staniforth]

Can a pilot tape over the dump holes to reduce noise, or is that a 
breach of contract?

Jim


On 4/21/2016 10:18 PM, DMcD wrote:

Locking the valve open at this time shouldn't cause any issue.

I don't think I could climb into my glider with the dump levers in the
open position!

D
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Re: [Aus-soaring] Fwd: Re: Fun with Form 2 Inspections and paperwork

[DMcD]

>>Locking the valve open at this time shouldn't cause any issue.

I don't think I could climb into my glider with the dump levers in the
open position!

D
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[Aus-soaring] Fwd: Re: Fun with Form 2 Inspections and paperwork

[Justin Couch]

Ben, got an early answer for you.

 Forwarded Message 
Subject: Re: Re: [Aus-soaring] Fun with Form 2 Inspections and paperwork
Date: Fri, 22 Apr 2016 11:38:37 +1000
From: Andrew Simpson 
To: Justin Couch 

Hi Justin,

Both requirements a) and b) need to be performed in applying PU 3.41.1 
ie the decal needs to be installed and the dump valve loced in an open

position.

This PU will most likely only be envoked on the sailplane during the 
form 2 inspection if the water tanks fails the AD testing. Locking the 
valve open at this time shouldn't cause any issue. Happy for people to 
contact me if the sailplane is outside the form 2 window at present and 
locking the valve open to comply is a difficult process that should 
really be done at the next form 2. In this case I am happy to work with 
the indivdual on a case be case bases to help them get to the next Form 
2 where the valve can be locked open.


Regards
Andrew

On Fri, Apr 22, 2016 at 11:00 AM, Justin Couch  wrote:


Guys,

Request for clarification on the Water Ballast actions in the new PU
document.


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