Cockpit Noise - Feb 2008

I weather-stripped the canopy following your excellent instructions.
Unfortunately it did not solve the problem. The noise was exactly the same. To
make sure that it was not caused by air coming through the gap between canopy
and airframe.

============================================================

Date:         Sun, 17 Feb 2008 22:04:28 -0700
Reply-To:     "Ximango Owners Group (XOG)" <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       "Ximango Owners Group (XOG)" <XIMANGO@HOME.EASE.LSOFT.COM>
From:         "Hermann F. Fasel" <faselh@EMAIL.ARIZONA.EDU>
Subject:      Cockpit noise
Comments: To: John Lawton <Thrmlseekr@AOL.COM>
MIME-Version: 1.0
Content-Type: text/plain; charset="ISO-8859-1"
Content-Disposition: inline
Content-Transfer-Encoding: 7bit

John,

I weather-stripped the canopy following your excellent instructions.
Unfortunately it did not solve the problem. The noise was exactly the same. To
make sure that it was not caused by air coming through the gap between canopy
and airframe, in a flight today I had a friend seal the gap all around the
canopy from the outside - using wingtape - after the canopy was locked down
prior to T/O. Again no effect on the noise. Therefore I am certain now
that the noise is not caused be air coming through the canopy gap. Then I sealed
the NACA air-scoops on the left and right outside of the cockpit, which provide
fresh air into the cockpit - also no effect. I have sealed and resealed the gaps
between wings and fuselage several times - also no effect. I am at a total loss
of what is going on.

Here is an updated summary of what I observed so far:
There is a terribly loud (high-frequency) whistling noise in the cockpit which
can not be tolerated even with my headset using active noise cancellation. The
noise is much stronger on the left side of the cockpit than on the right side.
When I put my hand on the (inside) wall of the cockpit (airframe - not the
canopy) I can feel a high frequency vibration (the canopy does not vibrate).
The wall of the right side of the cockpit does not vibrate. The noise occurs
both with engine on or off (thus it is not related to engine vibration). It
starts during takeoff (35-40KTS) and stops after landing. The noise (both
frequency) and amplitude) is insensitive to flight speed and plane attitude
(angle of attack) except when stalling the airplane (which gets me below the
35 KTS. The noise is the same with landing gear up or down.

Have you or anybody else experienced anything like that? I am desperate
because the airplane is not flyable and the mechanics I have asked also do not
have any idea.

Hermann


Hermann F. Fasel
Aerospace & Mechanical Engineering
University of Arizona
Tucson, Arizona 85721

Tel.: 520-621-2771
Fax: 520-621-8191


Quoting John Lawton <Thrmlseekr@AOL.COM>:

> In a message dated 1/24/2008 3:51:12 PM Eastern Standard Time,
> faselh@EMAIL.ARIZONA.EDU writes:
>
>>>>>> Where do you buy the foam? Is it standard material  or something
> special? What
> kind of tape do you suggest to attach the  foam?<<<<<<
>
> Hello Hermann,
>
> We use thin, self adhesive weather-strip available at any home  improvement
> store such as Lowe's, Home Depot, etc. Ace Hardware has good foam,  too. I
> particularly like the Ace Hardware brand foam because it has a thin  film of
> cellulose between the adhesive and the foam that makes removal
> easier. The gray
> Ace stuff seems to be a bit more UV resistant than  the tan stuff
> sold by Home
> Depot, too.
>
>  Get the thinnest you can find, i.e., 3/16" or thinner, open cell.  1/8"
> really works well, but is sometimes hard to find.  If you use
> anything  thicker or
> the closed cell variety, you run the risk of affecting the fit of  your
> canopy when closed. Apply when it's warm, say 60F or above. If you
> don't  get these
> sorts of temps, you can heat the mating surface slightly where  the foam is
> to be applied with a hair dryer or heat gun.
>
> You probably won't need the foam after temps warm up and the  existing closed
> cell foam becomes pliable again. Just peel off the open cell  foam when the
> temps warm up when you're done with it. Any residual adhesive  left
> behind will
> come off easily with acetone. Even though it's not  pretty, I would stick it
> to the fuselage, opposite the closed cell foam on the  canopy rail. You could
> stick it to the existing closed cell foam on  the canopy rail to keep it out
> of sight, but we've found that it doesn't stick  very well to the closed cell
> foam and usually peels off in a matter of a  few days, no matter how
> much prep
> you do.
>
> Wipe the surface where the foam is to be applied with acetone or  denatured
> alcohol before application to remove any grease or wax. Be careful if
>  you use
> acetone to keep it far away from the canopy itself. Acetone will harm  the
> Plexiglas canopy by making a frosty spot anywhere it contacts it.  If you do
> happen to get a drop on the canopy and the resulting frost, you  can
> sand it out
> (LIGHTLY) with 1200 then a light buff with plastic buffing  rouge
> will make it
> go away in most cases, but it's best to not go there.  Denatured alcohol will
> not harm the canopy. Neither acetone or denatured  alcohol will harm the
> finish, gel coat or urethane, although I wouldn't  leave a rag soaked
> with acetone
> sitting on any painted or gel coat surface  for long because after a while it
> will soften the paint or gel coat. Denatured  alcohol will not do
> this. Wiping
> the painted or gel coated surfaces with acetone  or denatured alcohol is
> fine, though.
>
> You can also use this type foam to seal up the fuel access doors and gear
> doors, both of which if not sealed are sources for drag because of
> the pressure
> differential between inside and outside the wing when at flying speeds.
>
> Anyway, hope it helps!
>
> Regards,
>
> John  Lawton
> Whitwell, TN (TN89)
> Ximango #135
>
>
>
> **************Biggest Grammy Award surprises of all time on AOL Music.
>
(http://music.aol.com/grammys/pictures/never-won-a-grammy?NCID=aolcmp003000000025
> 48)
=========================================================================
Date:         Mon, 18 Feb 2008 01:35:43 -0500
Reply-To:     "Ximango Owners Group (XOG)" <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       "Ximango Owners Group (XOG)" <XIMANGO@HOME.EASE.LSOFT.COM>
From:         Bruce SCHIMMEL <bruce@SCHIMMEL.COM>
Subject:      Re: Cockpit noise
In-Reply-To:  <20080217220428.vgp2dc4og88wcsco@www.email.arizona.edu>
Mime-Version: 1.0 (Apple Message framework v753)
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
Content-Transfer-Encoding: 7bit

Have you checked the tape that seals the wing root? I've noticed a 
screaming noise if that's not sealed right.
bruce
On Feb 18, 2008, at 12:04 AM, Hermann F. Fasel wrote:

John,

I weather-stripped the canopy following your excellent instructions.
Unfortunately it did not solve the problem. The noise was exactly the 
same. To
make sure that it was not caused by air coming through the gap 
between canopy
and airframe, in a flight today I had a friend seal the gap all 
around the
canopy from the outside - using wingtape - after the canopy was 
locked down
prior to T/O. Again no effect on the noise. Therefore I am certain now
that the noise is not caused be air coming through the canopy gap. 
Then I sealed
the NACA air-scoops on the left and right outside of the cockpit, 
which provide
fresh air into the cockpit - also no effect. I have sealed and 
resealed the gaps
between wings and fuselage several times - also no effect. I am at a 
total loss
of what is going on.

Here is an updated summary of what I observed so far:
There is a terribly loud (high-frequency) whistling noise in the 
cockpit which
can not be tolerated even with my headset using active noise 
cancellation. The
noise is much stronger on the left side of the cockpit than on the 
right side.
When I put my hand on the (inside) wall of the cockpit (airframe - 
not the
canopy) I can feel a high frequency vibration (the canopy does not 
vibrate).
The wall of the right side of the cockpit does not vibrate. The noise 
occurs
both with engine on or off (thus it is not related to engine 
vibration). It
starts during takeoff (35-40KTS) and stops after landing. The noise 
(both
frequency) and amplitude) is insensitive to flight speed and plane 
attitude
(angle of attack) except when stalling the airplane (which gets me 
below the
35 KTS. The noise is the same with landing gear up or down.

Have you or anybody else experienced anything like that? I am desperate
because the airplane is not flyable and the mechanics I have asked 
also do not
have any idea.

Hermann


Hermann F. Fasel
Aerospace & Mechanical Engineering
University of Arizona
Tucson, Arizona 85721

Tel.: 520-621-2771
Fax: 520-621-8191


Quoting John Lawton <Thrmlseekr@AOL.COM>:

> In a message dated 1/24/2008 3:51:12 PM Eastern Standard Time,
> faselh@EMAIL.ARIZONA.EDU writes:
>
>>>>>> Where do you buy the foam? Is it standard material  or something
> special? What
> kind of tape do you suggest to attach the  foam?<<<<<<
>
> Hello Hermann,
>
> We use thin, self adhesive weather-strip available at any home  
> improvement
> store such as Lowe's, Home Depot, etc. Ace Hardware has good foam,  
> too. I
> particularly like the Ace Hardware brand foam because it has a 
> thin  film of
> cellulose between the adhesive and the foam that makes removal
> easier. The gray
> Ace stuff seems to be a bit more UV resistant than  the tan stuff
> sold by Home
> Depot, too.
>
>  Get the thinnest you can find, i.e., 3/16" or thinner, open cell.  
> 1/8"
> really works well, but is sometimes hard to find.  If you use
> anything  thicker or
> the closed cell variety, you run the risk of affecting the fit of  
> your
> canopy when closed. Apply when it's warm, say 60F or above. If you
> don't  get these
> sorts of temps, you can heat the mating surface slightly where  the 
> foam is
> to be applied with a hair dryer or heat gun.
>
> You probably won't need the foam after temps warm up and the  
> existing closed
> cell foam becomes pliable again. Just peel off the open cell  foam 
> when the
> temps warm up when you're done with it. Any residual adhesive  left
> behind will
> come off easily with acetone. Even though it's not  pretty, I would 
> stick it
> to the fuselage, opposite the closed cell foam on the  canopy rail. 
> You could
> stick it to the existing closed cell foam on  the canopy rail to 
> keep it out
> of sight, but we've found that it doesn't stick  very well to the 
> closed cell
> foam and usually peels off in a matter of a  few days, no matter how
> much prep
> you do.
>
> Wipe the surface where the foam is to be applied with acetone or  
> denatured
> alcohol before application to remove any grease or wax. Be careful if
>  you use
> acetone to keep it far away from the canopy itself. Acetone will 
> harm  the
> Plexiglas canopy by making a frosty spot anywhere it contacts it.  
> If you do
> happen to get a drop on the canopy and the resulting frost, you  can
> sand it out
> (LIGHTLY) with 1200 then a light buff with plastic buffing  rouge
> will make it
> go away in most cases, but it's best to not go there.  Denatured 
> alcohol will
> not harm the canopy. Neither acetone or denatured  alcohol will 
> harm the
> finish, gel coat or urethane, although I wouldn't  leave a rag soaked
> with acetone
> sitting on any painted or gel coat surface  for long because after 
> a while it
> will soften the paint or gel coat. Denatured  alcohol will not do
> this. Wiping
> the painted or gel coated surfaces with acetone  or denatured 
> alcohol is
> fine, though.
>
> You can also use this type foam to seal up the fuel access doors 
> and gear
> doors, both of which if not sealed are sources for drag because of
> the pressure
> differential between inside and outside the wing when at flying 
> speeds.
>
> Anyway, hope it helps!
>
> Regards,
>
> John  Lawton
> Whitwell, TN (TN89)
> Ximango #135
>
>
>
> **************Biggest Grammy Award surprises of all time on AOL Music.
>
(http://music.aol.com/grammys/pictures/never-won-a-grammy?
NCID=aolcmp003000000025
> 48)
=========================================================================
Date:         Mon, 18 Feb 2008 06:58:05 -0600
Reply-To:     "Ximango Owners Group (XOG)" <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       "Ximango Owners Group (XOG)" <XIMANGO@HOME.EASE.LSOFT.COM>
From:         Ted Gordon <tedjgordon@ATT.NET>
Subject:      Re: Cockpit noise
MIME-Version: 1.0
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
              reply-type=response
Content-Transfer-Encoding: 7bit

Dear Hermann:

As Bruce suggests, the wing tape could do it.

Since it is obviously aerodynamic (doesn't happen at zero velocity as it
might from a defective gyro), then something must be vibrating as a result
of air flow above 35 kts. It's strong enough to transmit energy to the
fuselage side wall. So what could it be? The only things that occur to me
are: 1) the landing gear fairings or air flow through the LG wells might be
the cause or 2) vibration of the spoiler cap or air flow through the spoiler
wells.

Good luck.

Best
Ted


--------------------------------------------------
From: "Bruce SCHIMMEL" <bruce@SCHIMMEL.COM>
Sent: Monday, February 18, 2008 12:35 AM
To: <XIMANGO@HOME.EASE.LSOFT.COM>
Subject: Re: Cockpit noise

> Have you checked the tape that seals the wing root? I've noticed a
> screaming noise if that's not sealed right.
> bruce
> On Feb 18, 2008, at 12:04 AM, Hermann F. Fasel wrote:
>
> John,
>
> I weather-stripped the canopy following your excellent instructions.
> Unfortunately it did not solve the problem. The noise was exactly the
> same. To
> make sure that it was not caused by air coming through the gap  between
> canopy
> and airframe, in a flight today I had a friend seal the gap all  around
> the
> canopy from the outside - using wingtape - after the canopy was  locked
> down
> prior to T/O. Again no effect on the noise. Therefore I am certain now
> that the noise is not caused be air coming through the canopy gap.  Then I
> sealed
> the NACA air-scoops on the left and right outside of the cockpit,  which
> provide
> fresh air into the cockpit - also no effect. I have sealed and  resealed
> the gaps
> between wings and fuselage several times - also no effect. I am at a
> total loss
> of what is going on.
>
> Here is an updated summary of what I observed so far:
> There is a terribly loud (high-frequency) whistling noise in the  cockpit
> which
> can not be tolerated even with my headset using active noise
> cancellation. The
> noise is much stronger on the left side of the cockpit than on the  right
> side.
> When I put my hand on the (inside) wall of the cockpit (airframe -  not
> the
> canopy) I can feel a high frequency vibration (the canopy does not
> vibrate).
> The wall of the right side of the cockpit does not vibrate. The noise
> occurs
> both with engine on or off (thus it is not related to engine  vibration).
> It
> starts during takeoff (35-40KTS) and stops after landing. The noise  (both
> frequency) and amplitude) is insensitive to flight speed and plane
> attitude
> (angle of attack) except when stalling the airplane (which gets me  below
> the
> 35 KTS. The noise is the same with landing gear up or down.
>
> Have you or anybody else experienced anything like that? I am desperate
> because the airplane is not flyable and the mechanics I have asked  also
> do not
> have any idea.
>
> Hermann
>
>
> Hermann F. Fasel
> Aerospace & Mechanical Engineering
> University of Arizona
> Tucson, Arizona 85721
>
> Tel.: 520-621-2771
> Fax: 520-621-8191
>
>
> Quoting John Lawton <Thrmlseekr@AOL.COM>:
>
>> In a message dated 1/24/2008 3:51:12 PM Eastern Standard Time,
>> faselh@EMAIL.ARIZONA.EDU writes:
>>
>>>>>>> Where do you buy the foam? Is it standard material  or something
>> special? What
>> kind of tape do you suggest to attach the  foam?<<<<<<
>>
>> Hello Hermann,
>>
>> We use thin, self adhesive weather-strip available at any home
>> improvement
>> store such as Lowe's, Home Depot, etc. Ace Hardware has good foam,   too.
>> I
>> particularly like the Ace Hardware brand foam because it has a  thin
>> film of
>> cellulose between the adhesive and the foam that makes removal
>> easier. The gray
>> Ace stuff seems to be a bit more UV resistant than  the tan stuff
>> sold by Home
>> Depot, too.
>>
>>  Get the thinnest you can find, i.e., 3/16" or thinner, open cell.   1/8"
>> really works well, but is sometimes hard to find.  If you use
>> anything  thicker or
>> the closed cell variety, you run the risk of affecting the fit of   your
>> canopy when closed. Apply when it's warm, say 60F or above. If you
>> don't  get these
>> sorts of temps, you can heat the mating surface slightly where  the  foam
>> is
>> to be applied with a hair dryer or heat gun.
>>
>> You probably won't need the foam after temps warm up and the   existing
>> closed
>> cell foam becomes pliable again. Just peel off the open cell  foam  when
>> the
>> temps warm up when you're done with it. Any residual adhesive  left
>> behind will
>> come off easily with acetone. Even though it's not  pretty, I would
>> stick it
>> to the fuselage, opposite the closed cell foam on the  canopy rail.  You
>> could
>> stick it to the existing closed cell foam on  the canopy rail to  keep it
>> out
>> of sight, but we've found that it doesn't stick  very well to the  closed
>> cell
>> foam and usually peels off in a matter of a  few days, no matter how
>> much prep
>> you do.
>>
>> Wipe the surface where the foam is to be applied with acetone or
>> denatured
>> alcohol before application to remove any grease or wax. Be careful if
>>  you use
>> acetone to keep it far away from the canopy itself. Acetone will  harm
>> the
>> Plexiglas canopy by making a frosty spot anywhere it contacts it.   If
>> you do
>> happen to get a drop on the canopy and the resulting frost, you  can
>> sand it out
>> (LIGHTLY) with 1200 then a light buff with plastic buffing  rouge
>> will make it
>> go away in most cases, but it's best to not go there.  Denatured  alcohol
>> will
>> not harm the canopy. Neither acetone or denatured  alcohol will  harm the
>> finish, gel coat or urethane, although I wouldn't  leave a rag soaked
>> with acetone
>> sitting on any painted or gel coat surface  for long because after  a
>> while it
>> will soften the paint or gel coat. Denatured  alcohol will not do
>> this. Wiping
>> the painted or gel coated surfaces with acetone  or denatured  alcohol is
>> fine, though.
>>
>> You can also use this type foam to seal up the fuel access doors  and
>> gear
>> doors, both of which if not sealed are sources for drag because of
>> the pressure
>> differential between inside and outside the wing when at flying  speeds.
>>
>> Anyway, hope it helps!
>>
>> Regards,
>>
>> John  Lawton
>> Whitwell, TN (TN89)
>> Ximango #135
>>
>>
>>
>> **************Biggest Grammy Award surprises of all time on AOL Music.
>>
> (http://music.aol.com/grammys/pictures/never-won-a-grammy?
> NCID=aolcmp003000000025
>> 48)
>
=========================================================================
Date:         Mon, 18 Feb 2008 17:16:47 -0700
Reply-To:     "Ximango Owners Group (XOG)" <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       "Ximango Owners Group (XOG)" <XIMANGO@HOME.EASE.LSOFT.COM>
From:         "Hermann F. Fasel" <faselh@EMAIL.ARIZONA.EDU>
Subject:      Re: Cockpit noise
In-Reply-To:  <7C037F9A-4632-4373-A00B-3AFC517329DC@schimmel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="ISO-8859-1"; format="flowed"
Content-Disposition: inline
Content-Transfer-Encoding: 7bit

Bruce,
yes, I have checked the wing root tape. I sealed and resealed several
times with
no effect.

Hermann

Hermann F. Fasel
Aerospace & Mechanical Engineering
University of Arizona
Tucson, Arizona 85721

Tel.: 520-621-2771
Fax: 520-621-8191


Quoting Bruce SCHIMMEL <bruce@SCHIMMEL.COM>:

> Have you checked the tape that seals the wing root? I've noticed a
> screaming noise if that's not sealed right.
> bruce
> On Feb 18, 2008, at 12:04 AM, Hermann F. Fasel wrote:
>
> John,
>
> I weather-stripped the canopy following your excellent instructions.
> Unfortunately it did not solve the problem. The noise was exactly the
> same. To
> make sure that it was not caused by air coming through the gap
> between canopy
> and airframe, in a flight today I had a friend seal the gap all
> around the
> canopy from the outside - using wingtape - after the canopy was
> locked down
> prior to T/O. Again no effect on the noise. Therefore I am certain now
> that the noise is not caused be air coming through the canopy gap.
> Then I sealed
> the NACA air-scoops on the left and right outside of the cockpit,
> which provide
> fresh air into the cockpit - also no effect. I have sealed and
> resealed the gaps
> between wings and fuselage several times - also no effect. I am at a
> total loss
> of what is going on.
>
> Here is an updated summary of what I observed so far:
> There is a terribly loud (high-frequency) whistling noise in the
> cockpit which
> can not be tolerated even with my headset using active noise
> cancellation. The
> noise is much stronger on the left side of the cockpit than on the
> right side.
> When I put my hand on the (inside) wall of the cockpit (airframe -
> not the
> canopy) I can feel a high frequency vibration (the canopy does not
> vibrate).
> The wall of the right side of the cockpit does not vibrate. The noise
> occurs
> both with engine on or off (thus it is not related to engine
> vibration). It
> starts during takeoff (35-40KTS) and stops after landing. The noise
> (both
> frequency) and amplitude) is insensitive to flight speed and plane
> attitude
> (angle of attack) except when stalling the airplane (which gets me
> below the
> 35 KTS. The noise is the same with landing gear up or down.
>
> Have you or anybody else experienced anything like that? I am desperate
> because the airplane is not flyable and the mechanics I have asked
> also do not
> have any idea.
>
> Hermann
>
>
> Hermann F. Fasel
> Aerospace & Mechanical Engineering
> University of Arizona
> Tucson, Arizona 85721
>
> Tel.: 520-621-2771
> Fax: 520-621-8191
>
>
> Quoting John Lawton <Thrmlseekr@AOL.COM>:
>
>> In a message dated 1/24/2008 3:51:12 PM Eastern Standard Time,
>> faselh@EMAIL.ARIZONA.EDU writes:
>>
>>>>>>> Where do you buy the foam? Is it standard material  or something
>> special? What
>> kind of tape do you suggest to attach the  foam?<<<<<<
>>
>> Hello Hermann,
>>
>> We use thin, self adhesive weather-strip available at any home   improvement
>> store such as Lowe's, Home Depot, etc. Ace Hardware has good foam,   too. I
>> particularly like the Ace Hardware brand foam because it has a  thin
>>  film of
>> cellulose between the adhesive and the foam that makes removal
>> easier. The gray
>> Ace stuff seems to be a bit more UV resistant than  the tan stuff
>> sold by Home
>> Depot, too.
>>
>>  Get the thinnest you can find, i.e., 3/16" or thinner, open cell.   1/8"
>> really works well, but is sometimes hard to find.  If you use
>> anything  thicker or
>> the closed cell variety, you run the risk of affecting the fit of   your
>> canopy when closed. Apply when it's warm, say 60F or above. If you
>> don't  get these
>> sorts of temps, you can heat the mating surface slightly where  the  foam is
>> to be applied with a hair dryer or heat gun.
>>
>> You probably won't need the foam after temps warm up and the  
>> existing closed
>> cell foam becomes pliable again. Just peel off the open cell  foam  when the
>> temps warm up when you're done with it. Any residual adhesive  left
>> behind will
>> come off easily with acetone. Even though it's not  pretty, I would 
>> stick it
>> to the fuselage, opposite the closed cell foam on the  canopy rail. 
>> You could
>> stick it to the existing closed cell foam on  the canopy rail to 
>> keep it out
>> of sight, but we've found that it doesn't stick  very well to the 
>> closed cell
>> foam and usually peels off in a matter of a  few days, no matter how
>> much prep
>> you do.
>>
>> Wipe the surface where the foam is to be applied with acetone or   denatured
>> alcohol before application to remove any grease or wax. Be careful if
>>  you use
>> acetone to keep it far away from the canopy itself. Acetone will  harm  the
>> Plexiglas canopy by making a frosty spot anywhere it contacts it.  
>> If you do
>> happen to get a drop on the canopy and the resulting frost, you  can
>> sand it out
>> (LIGHTLY) with 1200 then a light buff with plastic buffing  rouge
>> will make it
>> go away in most cases, but it's best to not go there.  Denatured 
>> alcohol will
>> not harm the canopy. Neither acetone or denatured  alcohol will  harm the
>> finish, gel coat or urethane, although I wouldn't  leave a rag soaked
>> with acetone
>> sitting on any painted or gel coat surface  for long because after 
>> a while it
>> will soften the paint or gel coat. Denatured  alcohol will not do
>> this. Wiping
>> the painted or gel coated surfaces with acetone  or denatured  alcohol is
>> fine, though.
>>
>> You can also use this type foam to seal up the fuel access doors  and gear
>> doors, both of which if not sealed are sources for drag because of
>> the pressure
>> differential between inside and outside the wing when at flying  speeds.
>>
>> Anyway, hope it helps!
>>
>> Regards,
>>
>> John  Lawton
>> Whitwell, TN (TN89)
>> Ximango #135
>>
>>
>>
>> **************Biggest Grammy Award surprises of all time on AOL Music.
>>
> (http://music.aol.com/grammys/pictures/never-won-a-grammy?
> NCID=aolcmp003000000025
>> 48)
=========================================================================
Date:         Mon, 18 Feb 2008 19:20:53 -0500
Reply-To:     "Ximango Owners Group (XOG)" <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       "Ximango Owners Group (XOG)" <XIMANGO@HOME.EASE.LSOFT.COM>
From:         Bruce SCHIMMEL <bruce@SCHIMMEL.COM>
Subject:      Re: Cockpit noise
In-Reply-To:  <20080218171647.vbch0k0s848g0gco@www.email.arizona.edu>
Mime-Version: 1.0 (Apple Message framework v753)
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
Content-Transfer-Encoding: 7bit

jeez, the only other whistling I've heard is a badly-sealed gear 
door. but you get the same noise, gear up or down, right?


On Feb 18, 2008, at 7:16 PM, Hermann F. Fasel wrote:

Bruce,
yes, I have checked the wing root tape. I sealed and resealed several 
times with
no effect.

Hermann

Hermann F. Fasel
Aerospace & Mechanical Engineering
University of Arizona
Tucson, Arizona 85721

Tel.: 520-621-2771
Fax: 520-621-8191


Quoting Bruce SCHIMMEL <bruce@SCHIMMEL.COM>:

> Have you checked the tape that seals the wing root? I've noticed a
> screaming noise if that's not sealed right.
> bruce
> On Feb 18, 2008, at 12:04 AM, Hermann F. Fasel wrote:
>
> John,
>
> I weather-stripped the canopy following your excellent instructions.
> Unfortunately it did not solve the problem. The noise was exactly the
> same. To
> make sure that it was not caused by air coming through the gap
> between canopy
> and airframe, in a flight today I had a friend seal the gap all
> around the
> canopy from the outside - using wingtape - after the canopy was
> locked down
> prior to T/O. Again no effect on the noise. Therefore I am certain now
> that the noise is not caused be air coming through the canopy gap.
> Then I sealed
> the NACA air-scoops on the left and right outside of the cockpit,
> which provide
> fresh air into the cockpit - also no effect. I have sealed and
> resealed the gaps
> between wings and fuselage several times - also no effect. I am at a
> total loss
> of what is going on.
>
> Here is an updated summary of what I observed so far:
> There is a terribly loud (high-frequency) whistling noise in the
> cockpit which
> can not be tolerated even with my headset using active noise
> cancellation. The
> noise is much stronger on the left side of the cockpit than on the
> right side.
> When I put my hand on the (inside) wall of the cockpit (airframe -
> not the
> canopy) I can feel a high frequency vibration (the canopy does not
> vibrate).
> The wall of the right side of the cockpit does not vibrate. The noise
> occurs
> both with engine on or off (thus it is not related to engine
> vibration). It
> starts during takeoff (35-40KTS) and stops after landing. The noise
> (both
> frequency) and amplitude) is insensitive to flight speed and plane
> attitude
> (angle of attack) except when stalling the airplane (which gets me
> below the
> 35 KTS. The noise is the same with landing gear up or down.
>
> Have you or anybody else experienced anything like that? I am 
> desperate
> because the airplane is not flyable and the mechanics I have asked
> also do not
> have any idea.
>
> Hermann
>
>
> Hermann F. Fasel
> Aerospace & Mechanical Engineering
> University of Arizona
> Tucson, Arizona 85721
>
> Tel.: 520-621-2771
> Fax: 520-621-8191
>
>
> Quoting John Lawton <Thrmlseekr@AOL.COM>:
>
>> In a message dated 1/24/2008 3:51:12 PM Eastern Standard Time,
>> faselh@EMAIL.ARIZONA.EDU writes:
>>
>>>>>>> Where do you buy the foam? Is it standard material  or something
>> special? What
>> kind of tape do you suggest to attach the  foam?<<<<<<
>>
>> Hello Hermann,
>>
>> We use thin, self adhesive weather-strip available at any home   
>> improvement
>> store such as Lowe's, Home Depot, etc. Ace Hardware has good 
>> foam,   too. I
>> particularly like the Ace Hardware brand foam because it has a  
>> thin  film of
>> cellulose between the adhesive and the foam that makes removal
>> easier. The gray
>> Ace stuff seems to be a bit more UV resistant than  the tan stuff
>> sold by Home
>> Depot, too.
>>
>>  Get the thinnest you can find, i.e., 3/16" or thinner, open 
>> cell.   1/8"
>> really works well, but is sometimes hard to find.  If you use
>> anything  thicker or
>> the closed cell variety, you run the risk of affecting the fit 
>> of   your
>> canopy when closed. Apply when it's warm, say 60F or above. If you
>> don't  get these
>> sorts of temps, you can heat the mating surface slightly where  
>> the  foam is
>> to be applied with a hair dryer or heat gun.
>>
>> You probably won't need the foam after temps warm up and the   
>> existing closed
>> cell foam becomes pliable again. Just peel off the open cell  
>> foam  when the
>> temps warm up when you're done with it. Any residual adhesive  left
>> behind will
>> come off easily with acetone. Even though it's not  pretty, I 
>> would  stick it
>> to the fuselage, opposite the closed cell foam on the  canopy 
>> rail.  You could
>> stick it to the existing closed cell foam on  the canopy rail to  
>> keep it out
>> of sight, but we've found that it doesn't stick  very well to the  
>> closed cell
>> foam and usually peels off in a matter of a  few days, no matter how
>> much prep
>> you do.
>>
>> Wipe the surface where the foam is to be applied with acetone or   
>> denatured
>> alcohol before application to remove any grease or wax. Be careful if
>>  you use
>> acetone to keep it far away from the canopy itself. Acetone will  
>> harm  the
>> Plexiglas canopy by making a frosty spot anywhere it contacts 
>> it.   If you do
>> happen to get a drop on the canopy and the resulting frost, you  can
>> sand it out
>> (LIGHTLY) with 1200 then a light buff with plastic buffing  rouge
>> will make it
>> go away in most cases, but it's best to not go there.  Denatured  
>> alcohol will
>> not harm the canopy. Neither acetone or denatured  alcohol will  
>> harm the
>> finish, gel coat or urethane, although I wouldn't  leave a rag soaked
>> with acetone
>> sitting on any painted or gel coat surface  for long because 
>> after  a while it
>> will soften the paint or gel coat. Denatured  alcohol will not do
>> this. Wiping
>> the painted or gel coated surfaces with acetone  or denatured  
>> alcohol is
>> fine, though.
>>
>> You can also use this type foam to seal up the fuel access doors  
>> and gear
>> doors, both of which if not sealed are sources for drag because of
>> the pressure
>> differential between inside and outside the wing when at flying  
>> speeds.
>>
>> Anyway, hope it helps!
>>
>> Regards,
>>
>> John  Lawton
>> Whitwell, TN (TN89)
>> Ximango #135
>>
>>
>>
>> **************Biggest Grammy Award surprises of all time on AOL 
>> Music.
>>
> (http://music.aol.com/grammys/pictures/never-won-a-grammy?
> NCID=aolcmp003000000025
>> 48)
Date:         Mon, 18 Feb 2008 16:43:53 -0800
Reply-To:     "Ximango Owners Group (XOG)" <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       "Ximango Owners Group (XOG)" <XIMANGO@HOME.EASE.LSOFT.COM>
From:         Holliday Obrecht <HollidayObrecht@COPPER.NET>
Subject:      Re: Cockpit noise
MIME-Version: 1.0
Content-Type: text/plain; charset="UTF-8"

Hermann,

Did you check the little rivets on the leading edge of the wing folding fairings?  If this rivet is loose or missing, you will get a very loud whistling noise in the cockpit.  I had one fall out in flight.  The noise was very loud and scared me to death!  Hope you find out what the cause is.

Best regards,
Holliday Obrecht


--- faselh@EMAIL.ARIZONA.EDU wrote:

From:         "Hermann F. Fasel" <faselh@EMAIL.ARIZONA.EDU>
To:           XIMANGO@HOME.EASE.LSOFT.COM
Subject: Cockpit noise
Date:         Sun, 17 Feb 2008 22:04:28 -0700

John,

I weather-stripped the canopy following your excellent instructions.
Unfortunately it did not solve the problem. The noise was exactly the same. To
make sure that it was not caused by air coming through the gap between canopy
and airframe, in a flight today I had a friend seal the gap all around the
canopy from the outside - using wingtape - after the canopy was locked down
prior to T/O. Again no effect on the noise. Therefore I am certain now
that the noise is not caused be air coming through the canopy gap. Then I sealed
the NACA air-scoops on the left and right outside of the cockpit, which provide
fresh air into the cockpit - also no effect. I have sealed and resealed the gaps
between wings and fuselage several times - also no effect. I am at a total loss
of what is going on.

Here is an updated summary of what I observed so far:
There is a terribly loud (high-frequency) whistling noise in the cockpit which
can not be tolerated even with my headset using active noise cancellation. The
noise is much stronger on the left side of the cockpit than on the right side.
When I put my hand on the (inside) wall of the cockpit (airframe - not the
canopy) I can feel a high frequency vibration (the canopy does not vibrate).
The wall of the right side of the cockpit does not vibrate. The noise occurs
both with engine on or off (thus it is not related to engine vibration). It
starts during takeoff (35-40KTS) and stops after landing. The noise (both
frequency) and amplitude) is insensitive to flight speed and plane attitude
(angle of attack) except when stalling the airplane (which gets me below the
35 KTS. The noise is the same with landing gear up or down.

Have you or anybody else experienced anything like that? I am desperate
because the airplane is not flyable and the mechanics I have asked also do not
have any idea.

Hermann


Hermann F. Fasel
Aerospace & Mechanical Engineering
University of Arizona
Tucson, Arizona 85721

Tel.: 520-621-2771
Fax: 520-621-8191


Quoting John Lawton <Thrmlseekr@AOL.COM>:

> In a message dated 1/24/2008 3:51:12 PM Eastern Standard Time,
> faselh@EMAIL.ARIZONA.EDU writes:
>
>>>>>> Where do you buy the foam? Is it standard material  or something
> special? What
> kind of tape do you suggest to attach the  foam?<<<<<<
>
> Hello Hermann,
>
> We use thin, self adhesive weather-strip available at any home  improvement
> store such as Lowe's, Home Depot, etc. Ace Hardware has good foam,  too. I
> particularly like the Ace Hardware brand foam because it has a thin  film of
> cellulose between the adhesive and the foam that makes removal
> easier. The gray
> Ace stuff seems to be a bit more UV resistant than  the tan stuff
> sold by Home
> Depot, too.
>
>  Get the thinnest you can find, i.e., 3/16" or thinner, open cell.  1/8"
> really works well, but is sometimes hard to find.  If you use
> anything  thicker or
> the closed cell variety, you run the risk of affecting the fit of  your
> canopy when closed. Apply when it's warm, say 60F or above. If you
> don't  get these
> sorts of temps, you can heat the mating surface slightly where  the foam is
> to be applied with a hair dryer or heat gun.
>
> You probably won't need the foam after temps warm up and the  existing closed
> cell foam becomes pliable again. Just peel off the open cell  foam when the
> temps warm up when you're done with it. Any residual adhesive  left
> behind will
> come off easily with acetone. Even though it's not  pretty, I would stick it
> to the fuselage, opposite the closed cell foam on the  canopy rail. You could
> stick it to the existing closed cell foam on  the canopy rail to keep it out
> of sight, but we've found that it doesn't stick  very well to the closed cell
> foam and usually peels off in a matter of a  few days, no matter how
> much prep
> you do.
>
> Wipe the surface where the foam is to be applied with acetone or  denatured
> alcohol before application to remove any grease or wax. Be careful if
>  you use
> acetone to keep it far away from the canopy itself. Acetone will harm  the
> Plexiglas canopy by making a frosty spot anywhere it contacts it.  If you do
> happen to get a drop on the canopy and the resulting frost, you  can
> sand it out
> (LIGHTLY) with 1200 then a light buff with plastic buffing  rouge
> will make it
> go away in most cases, but it's best to not go there.  Denatured alcohol will
> not harm the canopy. Neither acetone or denatured  alcohol will harm the
> finish, gel coat or urethane, although I wouldn't  leave a rag soaked
> with acetone
> sitting on any painted or gel coat surface  for long because after a while it
> will soften the paint or gel coat. Denatured  alcohol will not do
> this. Wiping
> the painted or gel coated surfaces with acetone  or denatured alcohol is
> fine, though.
>
> You can also use this type foam to seal up the fuel access doors and gear
> doors, both of which if not sealed are sources for drag because of
> the pressure
> differential between inside and outside the wing when at flying speeds.
>
> Anyway, hope it helps!
>
> Regards,
>
> John  Lawton
> Whitwell, TN (TN89)
> Ximango #135
>
>
>
> **************Biggest Grammy Award surprises of all time on AOL Music.
>
(http://music.aol.com/grammys/pictures/never-won-a-grammy?NCID=aolcmp003000000025
> 48)
=========================================================================
Date:         Mon, 18 Feb 2008 19:25:16 -0700
Reply-To:     "Ximango Owners Group (XOG)" <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       "Ximango Owners Group (XOG)" <XIMANGO@HOME.EASE.LSOFT.COM>
From:         "Hermann F. Fasel" <faselh@EMAIL.ARIZONA.EDU>
Subject:      Re: Cockpit noise
In-Reply-To:  <9096A945-9416-4EFD-A7D7-4CD140641200@schimmel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="ISO-8859-1"; format="flowed"
Content-Disposition: inline
Content-Transfer-Encoding: 7bit

That is correct.
Hermann

Hermann F. Fasel
Aerospace & Mechanical Engineering
University of Arizona
Tucson, Arizona 85721

Tel.: 520-621-2771
Fax: 520-621-8191


Quoting Bruce SCHIMMEL <bruce@SCHIMMEL.COM>:

> jeez, the only other whistling I've heard is a badly-sealed gear
> door. but you get the same noise, gear up or down, right?
>
>
> On Feb 18, 2008, at 7:16 PM, Hermann F. Fasel wrote:
>
> Bruce,
> yes, I have checked the wing root tape. I sealed and resealed several
> times with
> no effect.
>
> Hermann
>
> Hermann F. Fasel
> Aerospace & Mechanical Engineering
> University of Arizona
> Tucson, Arizona 85721
>
> Tel.: 520-621-2771
> Fax: 520-621-8191
>
>
> Quoting Bruce SCHIMMEL <bruce@SCHIMMEL.COM>:
>
>> Have you checked the tape that seals the wing root? I've noticed a
>> screaming noise if that's not sealed right.
>> bruce
>> On Feb 18, 2008, at 12:04 AM, Hermann F. Fasel wrote:
>>
>> John,
>>
>> I weather-stripped the canopy following your excellent instructions.
>> Unfortunately it did not solve the problem. The noise was exactly the
>> same. To
>> make sure that it was not caused by air coming through the gap
>> between canopy
>> and airframe, in a flight today I had a friend seal the gap all
>> around the
>> canopy from the outside - using wingtape - after the canopy was
>> locked down
>> prior to T/O. Again no effect on the noise. Therefore I am certain now
>> that the noise is not caused be air coming through the canopy gap.
>> Then I sealed
>> the NACA air-scoops on the left and right outside of the cockpit,
>> which provide
>> fresh air into the cockpit - also no effect. I have sealed and
>> resealed the gaps
>> between wings and fuselage several times - also no effect. I am at a
>> total loss
>> of what is going on.
>>
>> Here is an updated summary of what I observed so far:
>> There is a terribly loud (high-frequency) whistling noise in the
>> cockpit which
>> can not be tolerated even with my headset using active noise
>> cancellation. The
>> noise is much stronger on the left side of the cockpit than on the
>> right side.
>> When I put my hand on the (inside) wall of the cockpit (airframe -
>> not the
>> canopy) I can feel a high frequency vibration (the canopy does not
>> vibrate).
>> The wall of the right side of the cockpit does not vibrate. The noise
>> occurs
>> both with engine on or off (thus it is not related to engine
>> vibration). It
>> starts during takeoff (35-40KTS) and stops after landing. The noise
>> (both
>> frequency) and amplitude) is insensitive to flight speed and plane
>> attitude
>> (angle of attack) except when stalling the airplane (which gets me
>> below the
>> 35 KTS. The noise is the same with landing gear up or down.
>>
>> Have you or anybody else experienced anything like that? I am  desperate
>> because the airplane is not flyable and the mechanics I have asked
>> also do not
>> have any idea.
>>
>> Hermann
>>
>>
>> Hermann F. Fasel
>> Aerospace & Mechanical Engineering
>> University of Arizona
>> Tucson, Arizona 85721
>>
>> Tel.: 520-621-2771
>> Fax: 520-621-8191
>>
>>
>> Quoting John Lawton <Thrmlseekr@AOL.COM>:
>>
>>> In a message dated 1/24/2008 3:51:12 PM Eastern Standard Time,
>>> faselh@EMAIL.ARIZONA.EDU writes:
>>>
>>>>>>>> Where do you buy the foam? Is it standard material  or something
>>> special? What
>>> kind of tape do you suggest to attach the  foam?<<<<<<
>>>
>>> Hello Hermann,
>>>
>>> We use thin, self adhesive weather-strip available at any home   
>>> improvement
>>> store such as Lowe's, Home Depot, etc. Ace Hardware has good  foam,
>>>   too. I
>>> particularly like the Ace Hardware brand foam because it has a  
>>> thin  film of
>>> cellulose between the adhesive and the foam that makes removal
>>> easier. The gray
>>> Ace stuff seems to be a bit more UV resistant than  the tan stuff
>>> sold by Home
>>> Depot, too.
>>>
>>>  Get the thinnest you can find, i.e., 3/16" or thinner, open  cell.   1/8"
>>> really works well, but is sometimes hard to find.  If you use
>>> anything  thicker or
>>> the closed cell variety, you run the risk of affecting the fit  of   your
>>> canopy when closed. Apply when it's warm, say 60F or above. If you
>>> don't  get these
>>> sorts of temps, you can heat the mating surface slightly where  
>>> the  foam is
>>> to be applied with a hair dryer or heat gun.
>>>
>>> You probably won't need the foam after temps warm up and the   
>>> existing closed
>>> cell foam becomes pliable again. Just peel off the open cell   foam
>>>  when the
>>> temps warm up when you're done with it. Any residual adhesive  left
>>> behind will
>>> come off easily with acetone. Even though it's not  pretty, I 
>>> would  stick it
>>> to the fuselage, opposite the closed cell foam on the  canopy 
>>> rail.  You could
>>> stick it to the existing closed cell foam on  the canopy rail to  
>>> keep it out
>>> of sight, but we've found that it doesn't stick  very well to the  
>>> closed cell
>>> foam and usually peels off in a matter of a  few days, no matter how
>>> much prep
>>> you do.
>>>
>>> Wipe the surface where the foam is to be applied with acetone or   
>>> denatured
>>> alcohol before application to remove any grease or wax. Be careful if
>>>  you use
>>> acetone to keep it far away from the canopy itself. Acetone will  
>>> harm  the
>>> Plexiglas canopy by making a frosty spot anywhere it contacts  it. 
>>>  If you do
>>> happen to get a drop on the canopy and the resulting frost, you  can
>>> sand it out
>>> (LIGHTLY) with 1200 then a light buff with plastic buffing  rouge
>>> will make it
>>> go away in most cases, but it's best to not go there.  Denatured  
>>> alcohol will
>>> not harm the canopy. Neither acetone or denatured  alcohol will   harm the
>>> finish, gel coat or urethane, although I wouldn't  leave a rag soaked
>>> with acetone
>>> sitting on any painted or gel coat surface  for long because  after
>>>  a while it
>>> will soften the paint or gel coat. Denatured  alcohol will not do
>>> this. Wiping
>>> the painted or gel coated surfaces with acetone  or denatured   alcohol is
>>> fine, though.
>>>
>>> You can also use this type foam to seal up the fuel access doors   and gear
>>> doors, both of which if not sealed are sources for drag because of
>>> the pressure
>>> differential between inside and outside the wing when at flying   speeds.
>>>
>>> Anyway, hope it helps!
>>>
>>> Regards,
>>>
>>> John  Lawton
>>> Whitwell, TN (TN89)
>>> Ximango #135
>>>
>>>