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ssssskippy
Joined: 02 May 2010
Posts: 58
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dsavarese0812(at)bellsout
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 Posted: Sun Jun 10, 2012 10:55 am Post subject: how not to crack your yak52 fuel tanks |
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It is my opinion the problem with the Yak 52 fuel tanks is the flexing
of the tank metal due to vapor expansion during hot weather. This is
prevalent in all Yak 52's with the single vent tube on the belly of the
airplane and very rarely seen on Yak 52's with dual vent lines exiting
the belly of the airplane. (Post 1989 manufacture). If the Yak 52 is
left in the sun without venting the fuel tanks by loosening the fuel
caps, the expansion of the fuel vapor causes the very thin fuel tank
metal to expand, thus flexing the fuel tank. The constant flexing and
contracting during hot weather ultimately causes the tank to fracture.
Many (more than 50%) of the leaks appear around the weld points on the
bottom of the tank where the interior baffles are welded to the exterior
metal.
I seriously doubt hard aerobatics would cause the tank to fracture
because the tank has several baffles inside the tank which prevent the
fuel from sloshing back and forth.
I also doubt bumping on a grass field with full tanks would cause the
metal to crack.
The constant flexing of the tank metal due to a very poor tank vent
system design is more likely the cause of the metal fracturing.
Dennis
A. Dennis Savarese
334-285-6263
334-546-8182 (mobile)
www.yak-52.com
Skype - Yakguy1
On 6/10/2012 1:29 PM, Olivier Vigneron wrote:
| Quote: | Hi All
I encounter some difficulty with reccurents issues about gas tanks
that are leaking.
An aero welder told me that are the results of hard aerobatics with
half full tanks . As the fuel is able to hit the tank wall.
Yesterday a lituanian mechanic told me that are the results of
bumping on grass field with full tanks on hot days.....
Who's says the truth? The welder? The lituanian? both? 
This discussion is about to make an aerobatics policy to avoid tank
cracking !
Thanks
Olivier
*
*
|
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cjpilot710(at)aol.com
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| Posted: Sun Jun 10, 2012 5:31 pm Post subject: how not to crack your yak52 fuel tanks |
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Test 1234.
I'll go along with Dennis views. But I would like to add one more which I really think it is the primary cause for cracks showing up. Vibration, constant and rather high amplitude vibrations. At times these vibrations can hit harmonic resonance with the different parts of the metal structures, that hardens or crystallize though the metal and that usually shows up as cracks particularly around weldments. These are areas where stress tends concentrated. Most of this vibration comes from the engine. If the shocks in the engine mount are old, bottomed out, the vibration from the engine can be incredible throughout the airframe. Particularly in acrobatics. A friend of mine who is a test pilot for Extra, can actually feel a shock bottoming out while doing outside snaps.
While fuel sloshing around in the tank during acrobatics sounds logical, but because of where the fuel is located (usually near the CG), I do not believe there is enough room in the tank for fuel to build up some inertia against a tank wall. Especially with any kind of baffling inside.
I would look at the total time on the airplane. The longer it is exposed to these vibrations I believe you will see more cracks. Vibrations can be very insidious. In the mid-50s a number of Lockheed Electra's (four engine turbo prop) had wings come off in cruise flight due to harmonic vibrations set up by the outboard engines. It was my understanding as a young teenager that harmonic vibration caused the spar at the center section of the wing, basically to become work harden and crack. A little more complicated than that but basically that. To this day, Lockheed, the Navy and a number of firefighting companies, have a joint program monitoring the wing conditions of the Elektra. The fix if I remember correctly was a change in the engine mounts and thicker wing skins.
Like Dennis I doubt bumping on a grass field with full tanks caused the fuel tanks to crack UNLESS that airplane is pretty tired already.
Jim "Pappy" Goolsby
In a message dated 6/ aerobatics would cause the tank to fracture
because the tank has several baffles inside the tank which prevent the
fuel from sloshing back and forth.
I also doubt bumping on a grass field with full tanks would cause the
metal to crack.
The constant flexing of the tank metal due to a very poor tank vent
system design is more likely the cause of the metal fracturing.
Dennis
A. Dennis Savarese
334-285-6263
334-546-8182 (mobile)
www.yak-52.com
Skype - Yakguy1
On 6/10/2012 1:29 PM, Olivier Vigneron wrote:
| Quote: | Hi All
I encounter some difficulty with reccurents issues about gas tanks
that are leaking.
An aero welder told me that are the results of hard aerobatics with
half full tanks . As the fuel is able to hit the tank wall.
Yesterday a lituanian mechanic told me that are the results of
bumping on grass field with full tanks on hot days.....
Who's says the truth? The welder? The lituanian? both?
This discussion is about to make an aerobatics policy to avoid tank
cracking !
Thanks
Olivier
*
s such se, --> - MATRONICS WEB FORUMS -
|
[quote][b]
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flying(at)jeffhove.com
Guest
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| Posted: Sun Jun 10, 2012 9:21 pm Post subject: how not to crack your yak52 fuel tanks |
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How hard is it to modify a single-vent Yak-52 to the newer dual-vent
system? Are instructions or a kit available?
Jeff Hove
On 6/10/2012 1:49 PM, A. Dennis Savarese wrote:
| Quote: |
<dsavarese0812(at)bellsouth.net>
It is my opinion the problem with the Yak 52 fuel tanks is the flexing
of the tank metal due to vapor expansion during hot weather. This is
prevalent in all Yak 52's with the single vent tube on the belly of
the airplane and very rarely seen on Yak 52's with dual vent lines
exiting the belly of the airplane. (Post 1989 manufacture). If the
Yak 52 is left in the sun without venting the fuel tanks by loosening
the fuel caps, the expansion of the fuel vapor causes the very thin
fuel tank metal to expand, thus flexing the fuel tank. The constant
flexing and contracting during hot weather ultimately causes the tank
to fracture.
Many (more than 50%) of the leaks appear around the weld points on the
bottom of the tank where the interior baffles are welded to the
exterior metal.
I seriously doubt hard aerobatics would cause the tank to fracture
because the tank has several baffles inside the tank which prevent the
fuel from sloshing back and forth.
I also doubt bumping on a grass field with full tanks would cause the
metal to crack.
The constant flexing of the tank metal due to a very poor tank vent
system design is more likely the cause of the metal fracturing.
Dennis
A. Dennis Savarese
334-285-6263
334-546-8182 (mobile)
www.yak-52.com
Skype - Yakguy1
On 6/10/2012 1:29 PM, Olivier Vigneron wrote:
> Hi All
>
> I encounter some difficulty with reccurents issues about gas tanks
> that are leaking.
>
> An aero welder told me that are the results of hard aerobatics with
> half full tanks . As the fuel is able to hit the tank wall.
>
> Yesterday a lituanian mechanic told me that are the results of
> bumping on grass field with full tanks on hot days.....
> Who's says the truth? The welder? The lituanian? both?
>
> This discussion is about to make an aerobatics policy to avoid tank
> cracking !
>
> Thanks
>
> Olivier
> *
> *
|
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ssssskippy
Joined: 02 May 2010
Posts: 58
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| Posted: Sun Jun 10, 2012 10:37 pm Post subject: how not to crack your yak52 fuel tanks |
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Hi Jim
What you wrote sounds strangely accurate to me....! My yak52 is my first one and my first plane too.
I fly very often with a friend that had a yak52 and he was always complaining because "my plane was so shaky that he lost all his teeth"
As it's my first yak52, I had no comparaison at all...and I talked about those vibrations to the lituanians mechanic. He started the engine and found that was really shaky so he tested the prop balancing.
The vibrations was very high and after prop balancing it is now perfect.
So, now, I'm not surprised about cracks as result of heavy vibrations.....
Thanks
Olivier
2012/6/11 <cjpilot710(at)aol.com (cjpilot710(at)aol.com)>
[quote]
Test 1234.
I'll go along with Dennis views. But I would like to add one more which I really think it is the primary cause for cracks showing up. Vibration, constant and rather high amplitude vibrations. At times these vibrations can hit harmonic resonance with the different parts of the metal structures, that hardens or crystallize though the metal and that usually shows up as cracks particularly around weldments. These are areas where stress tends concentrated. Most of this vibration comes from the engine. If the shocks in the engine mount are old, bottomed out, the vibration from the engine can be incredible throughout the airframe. Particularly in acrobatics. A friend of mine who is a test pilot for Extra, can actually feel a shock bottoming out while doing outside snaps.
While fuel sloshing around in the tank during acrobatics sounds logical, but because of where the fuel is located (usually near the CG), I do not believe there is enough room in the tank for fuel to build up some inertia against a tank wall. Especially with any kind of baffling inside.
I would look at the total time on the airplane. The longer it is exposed to these vibrations I believe you will see more cracks. Vibrations can be very insidious. In the mid-50s a number of Lockheed Electra's (four engine turbo prop) had wings come off in cruise flight due to harmonic vibrations set up by the outboard engines. It was my understanding as a young teenager that harmonic vibration caused the spar at the center section of the wing, basically to become work harden and crack. A little more complicated than that but basically that. To this day, Lockheed, the Navy and a number of firefighting companies, have a joint program monitoring the wing conditions of the Elektra. The fix if I remember correctly was a change in the engine mounts and thicker wing skins.
Like Dennis I doubt bumping on a grass field with full tanks caused the fuel tanks to crack UNLESS that airplane is pretty tired already.
Jim "Pappy" Goolsby
In a message dated 6/ aerobatics would cause the tank to fracture
because the tank has several baffles inside the tank which prevent the
fuel from sloshing back and forth.
I also doubt bumping on a grass field with full tanks would cause the
metal to crack.
The constant flexing of the tank metal due to a very poor tank vent
system design is more likely the cause of the metal fracturing.
Dennis
A. Dennis Savarese
[url=tel:334-285-6263]334-285-6263[/url]
[url=tel:334-546-8182]334-546-8182[/url] (mobile)
www.yak-52.com
Skype - Yakguy1
On 6/10/2012 1:29 PM, Olivier Vigneron wrote:
| Quote: | Hi All
I encounter some difficulty with reccurents issues about gas tanks
that are leaking.
An aero welder told me that are the results of hard aerobatics with
half full tanks . As the fuel is able to hit the tank wall.
Yesterday a lituanian mechanic told me that are the results of
bumping on grass field with full tanks on hot days.....
Who's says the truth? The welder? The lituanian? both?
This discussion is about to make an aerobatics policy to avoid tank
cracking !
Thanks
Olivier
*
|
| Quote: | s such se, --> - MATRONICS WEB FORUMS -
|
| Quote: |
et="_blank">http://www.matronics.com/Navigator?Yak-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
|
[b]
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dsavarese0812(at)bellsout
Guest
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| Posted: Mon Jun 11, 2012 3:25 am Post subject: how not to crack your yak52 fuel tanks |
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Definitely not easy and to my knowledge, no kit is available.
Just to even think about it, the fuel tanks must have a capped off
fitting on the outboard, top end of the tanks. This is where the second
vent line is attached.
Dennis
A. Dennis Savarese
334-285-6263
334-546-8182 (mobile)
www.yak-52.com
Skype - Yakguy1
On 6/11/2012 12:20 AM, Jeff Hove wrote:
| Quote: |
How hard is it to modify a single-vent Yak-52 to the newer dual-vent
system? Are instructions or a kit available?
Jeff Hove
On 6/10/2012 1:49 PM, A. Dennis Savarese wrote:
>
> <dsavarese0812(at)bellsouth.net>
>
> It is my opinion the problem with the Yak 52 fuel tanks is the
> flexing of the tank metal due to vapor expansion during hot
> weather. This is prevalent in all Yak 52's with the single vent
> tube on the belly of the airplane and very rarely seen on Yak 52's
> with dual vent lines exiting the belly of the airplane. (Post 1989
> manufacture). If the Yak 52 is left in the sun without venting the
> fuel tanks by loosening the fuel caps, the expansion of the fuel
> vapor causes the very thin fuel tank metal to expand, thus flexing
> the fuel tank. The constant flexing and contracting during hot
> weather ultimately causes the tank to fracture.
>
> Many (more than 50%) of the leaks appear around the weld points on
> the bottom of the tank where the interior baffles are welded to the
> exterior metal.
>
> I seriously doubt hard aerobatics would cause the tank to fracture
> because the tank has several baffles inside the tank which prevent
> the fuel from sloshing back and forth.
>
> I also doubt bumping on a grass field with full tanks would cause the
> metal to crack.
>
> The constant flexing of the tank metal due to a very poor tank vent
> system design is more likely the cause of the metal fracturing.
>
> Dennis
> A. Dennis Savarese
> 334-285-6263
> 334-546-8182 (mobile)
> www.yak-52.com
> Skype - Yakguy1
> On 6/10/2012 1:29 PM, Olivier Vigneron wrote:
>> Hi All
>>
>> I encounter some difficulty with reccurents issues about gas tanks
>> that are leaking.
>>
>> An aero welder told me that are the results of hard aerobatics with
>> half full tanks . As the fuel is able to hit the tank wall.
>>
>> Yesterday a lituanian mechanic told me that are the results of
>> bumping on grass field with full tanks on hot days.....
>>
>>
>> Who's says the truth? The welder? The lituanian? both?
>>
>> This discussion is about to make an aerobatics policy to avoid tank
>> cracking !
>>
>> Thanks
>>
>> Olivier
>> *
>>
>>
>> *
>
|
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rmfitz929(at)gmail.com
Guest
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| Posted: Mon Jun 11, 2012 6:54 am Post subject: how not to crack your yak52 fuel tanks |
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There has been good advice on this topic from experienced sources.
Here is another view.
My Yak is a '93 model with dual vents, no Russian time and a balanced
prop. At about 250hrs it had a tank leak anyway.
My personal (unqualified) opinion puts the cause as acro with full
tanks. I am not a fan of violent acro (no snaps or tumbles) but pulling
6g on a full tank puts a lot of pressure on a very thin, flat bottomed
tank. After pulling and replacing the repaired tank i have been
religious about keeping g loads inversely proportionate to fuel loads.
That means don't pull hard with tanks over half full. Following that
practice for over 300hrs has resulted in no more leaks, so far. YMMV
Boris 52BN
PS It took a while to figure out the tank was leaking. For a time there
was a gas smell, only during acro, that we could not trace. Eventually
the crack expanded and fuel started dripping out of the wing. If you
pull G's and smell gas, it's time to check your tanks.
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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bwade154(at)yahoo.com
Guest
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| Posted: Mon Jun 11, 2012 10:50 am Post subject: how not to crack your yak52 fuel tanks |
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Dennis weren't you providing bladder tanks for the Yak 52? how are they holding up? the guys and gals that purchased doing a lot of acro?
Bill Wade
From: A. Dennis Savarese <dsavarese0812(at)bellsouth.net>
To: yak-list(at)matronics.com
Sent: Monday, June 11, 2012 7:21 AM
Subject: Re: how not to crack your yak52 fuel tanks
--> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Definitely not easy and to my knowledge, no kit is available.
Just to even think about it, the fuel tanks must have a capped off fitting on the outboard, top end of the tanks. This is where the second vent line is attached.
Dennis
A. Dennis Savarese
334-285-6263
334-546-8182 (mobile)
www.yak-52.com
Skype - Yakguy1
On 6/11/2012 12:20 AM, Jeff Hove wrote:
| Quote: | --> Yak-List message posted by: Jeff Hove <flying(at)jeffhove.com (flying(at)jeffhove.com)>
How hard is it to modify a single-vent Yak-52 to the newer dual-vent system? Are instructions or a kit available?
Jeff Hove
On 6/10/2012 1:49 PM, A. Dennis Savarese wrote:
> --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
>
> It is my opinion the problem with the Yak 52 fuel tanks is the flexing of the tank metal due to vapor expansion during hot weather. This is prevalent in all Yak 52's with the single vent tube on the belly of the airplane and very rarely seen on Yak 52's with dual vent lines exiting the belly of the airplane. (Post 1989 manufacture). If the Yak 52 is left in the sun without venting the fuel tanks by loosening the fuel caps, the expansion of the fuel vapor causes the very thin fuel tank metal to expand, thus flexing the fuel tank. The constant flexing and contracting during hot weather ultimately causes the tank to fracture.
>
> Many (more than 50%) of the leaks appear around the weld points on the bottom of the tank where the interior baffles are welded to the exterior metal.
>
> I seriously doubt hard aerobatics would cause the tank to fracture because the tank has several baffles inside the tank which prevent the fuel from sloshing back and forth.
>
> I also doubt bumping on a grass field with full tanks would cause the metal to crack.
>
> The constant flexing of the tank metal due to a very poor tank vent system design is more likely the cause of the metal fracturing.
>
> Dennis
>
>
> A. Dennis Savarese
> 334-285-6263
> 334-546-8182 (mobile)
> www.yak-52.com
> Skype - Yakguy1
>
>
> On 6/10/2012 1:29 PM, Olivier Vigneron wrote:
>> Hi All
>>
>> I encounter some difficulty with reccurents issues about gas tanks that are leaking.
>>
>> An aero welder told me that are the results of hard aerobatics with half full tanks . As the fuel is able to hit the tank wall.
>>
>> Yesterday a lituanian mechanic told me that are the results of bumping on grass field with full tanks on hot days.....
>>
>>
>> Who's says the truth? The welder? The lituanian? both?
>>
>> This discussion is about to make an aerobatics policy to avoid tank cracking !
>>
>> Thanks
>>
>> Olivier
>> *
>>
>>
>> *
>
>
>
> id="misspell-19" class="mark">Photoshare, and much much more:http://www.matronics.com/Navigator?Yak-List</ -Matt Dralle
|
[quote][b]
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http://www.matronics.com/Navigator?Yak-List |
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dsavarese0812(at)bellsout
Guest
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| Posted: Mon Jun 11, 2012 11:40 am Post subject: how not to crack your yak52 fuel tanks |
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|
Yes, we still offer the bladder tanks and they seem to do quite well. I
can't answer the question as to whether they are doing a lot of acro or
not. The primary purpose of the bladders was to increase the very
limited fuel range of the 52. We also recommend when installing the
bladders, no acro with more than the standard fuel capacity of the
original metal tanks. I do know a couple of the guys on one of the
Yak/CJ demo teams that installed the bladders. They commented that
everything was doing well.
One thing for certain, the bladders are filled with fuel proof foam
which eliminates any sloshing of the fuel. You can see this on my web
site, www.yak-52.com and click on the button at the top 'Yak 52 Fuel
Bladders'.
Here's a photo of one of the bladders. You can see the blue foam inside
the oval filler plate opening.
Dennis
A. Dennis Savarese
334-285-6263
334-546-8182 (mobile)
www.yak-52.com
Skype - Yakguy1
On 6/11/2012 1:46 PM, bill wade wrote:
| Quote: | Dennis weren't you providing bladder tanks for the Yak 52? how are
they holding up? the guys and gals that purchased doing a lot of acro?
Bill Wade
*From:* A. Dennis Savarese <dsavarese0812(at)bellsouth.net>
*To:* yak-list(at)matronics.com
*Sent:* Monday, June 11, 2012 7:21 AM
*Subject:* Re: how not to crack your yak52 fuel tanks
<dsavarese0812(at)bellsouth.net <mailto:dsavarese0812(at)bellsouth.net>>
Definitely not easy and to my knowledge, no kit is available.
Just to even think about it, the fuel tanks must have a capped off
fitting on the outboard, top end of the tanks. This is where the
second vent line is attached.
Dennis
A. Dennis Savarese
334-285-6263
334-546-8182 (mobile)
www.yak-52.com <http://www.yak-52.com>
Skype - Yakguy1
On 6/11/2012 12:20 AM, Jeff Hove wrote:
>
<mailto:flying(at)jeffhove.com>>
>
> How hard is it to modify a single-vent Yak-52 to the newer dual-vent
system? Are instructions or a kit available?
>
> Jeff Hove
>
> On 6/10/2012 1:49 PM, A. Dennis Savarese wrote:
>>
<dsavarese0812(at)bellsouth.net <mailto:dsavarese0812(at)bellsouth.net>>
>>
>> It is my opinion the problem with the Yak 52 fuel tanks is the
flexing of the tank metal due to vapor expansion during hot weather.
This is prevalent in all Yak 52's with the single vent tube on the
belly of the airplane and very rarely seen on Yak 52's with dual vent
lines exiting the belly of the airplane. (Post 1989 manufacture). If
the Yak 52 is left in the sun without venting the fuel tanks by
loosening the fuel caps, the expansion of the fuel vapor causes the
very thin fuel tank metal to expand, thus flexing the fuel tank. The
constant flexing and contracting during hot weather ultimately causes
the tank to fracture.
>>
>> Many (more than 50%) of the leaks appear around the weld points on
the bottom of the tank where the interior baffles are welded to the
exterior metal.
>>
>> I seriously doubt hard aerobatics would cause the tank to fracture
because the tank has several baffles inside the tank which prevent the
fuel from sloshing back and forth.
>>
>> I also doubt bumping on a grass field with full tanks would cause
the metal to crack.
>>
>> The constant flexing of the tank metal due to a very poor tank vent
system design is more likely the cause of the metal fracturing.
>>
>> Dennis
>>
>>
>> A. Dennis Savarese
>> 334-285-6263
>> 334-546-8182 (mobile)
>> www.yak-52.com
>> Skype - Yakguy1
>>
>>
>> On 6/10/2012 1:29 PM, Olivier Vigneron wrote:
>>> Hi All
>>>
>>> I encounter some difficulty with reccurents issues about gas tanks
that are leaking.
>>>
>>> An aero welder told me that are the results of hard aerobatics
with half full tanks . As the fuel is able to hit the tank wall.
>>>
>>> Yesterday a lituanian mechanic told me that are the results of
bumping on grass field with full tanks on hot days.....
>>>
>>>
>>> Who's says the truth? The welder? The lituanian? both?
>>>
>>> This discussion is about to make an aerobatics policy to avoid
tank cracking !
>>>
>>> Thanks
>>>
>>> Olivier
>>> *
>>>
>>>
>>> *
>>
>>
>>
>> id="misspell-19" class="mark">Photoshare, and much much
more:http://www.matronics.com/Navigator?Yak-ListDralle
*
*
|
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dsavarese0812(at)bellsout
Guest
|
| Posted: Mon Jun 11, 2012 12:25 pm Post subject: how not to crack your yak52 fuel tanks |
|
|
I guess the photo did not make it.
Dennis
A. Dennis Savarese
334-285-6263
334-546-8182 (mobile)
www.yak-52.com
Skype - Yakguy1
On 6/11/2012 2:36 PM, A. Dennis Savarese wrote:
| Quote: |
<dsavarese0812(at)bellsouth.net>
Yes, we still offer the bladder tanks and they seem to do quite well.
I can't answer the question as to whether they are doing a lot of acro
or not. The primary purpose of the bladders was to increase the very
limited fuel range of the 52. We also recommend when installing the
bladders, no acro with more than the standard fuel capacity of the
original metal tanks. I do know a couple of the guys on one of the
Yak/CJ demo teams that installed the bladders. They commented that
everything was doing well.
One thing for certain, the bladders are filled with fuel proof foam
which eliminates any sloshing of the fuel. You can see this on my
web site, www.yak-52.com and click on the button at the top 'Yak 52
Fuel Bladders'.
Here's a photo of one of the bladders. You can see the blue foam
inside the oval filler plate opening.
Dennis
A. Dennis Savarese
334-285-6263
334-546-8182 (mobile)
www.yak-52.com
Skype - Yakguy1
On 6/11/2012 1:46 PM, bill wade wrote:
> Dennis weren't you providing bladder tanks for the Yak 52? how are
> they holding up? the guys and gals that purchased doing a lot of acro?
> Bill Wade
>
> *From:* A. Dennis Savarese <dsavarese0812(at)bellsouth.net>
> *To:* yak-list(at)matronics.com
> *Sent:* Monday, June 11, 2012 7:21 AM
> *Subject:* Re: how not to crack your yak52 fuel tanks
>
>
> <dsavarese0812(at)bellsouth.net <mailto:dsavarese0812(at)bellsouth.net>>
>
> Definitely not easy and to my knowledge, no kit is available.
>
> Just to even think about it, the fuel tanks must have a capped off
> fitting on the outboard, top end of the tanks. This is where the
> second vent line is attached.
> Dennis
>
> A. Dennis Savarese
> 334-285-6263
> 334-546-8182 (mobile)
> www.yak-52.com <http://www.yak-52.com>
> Skype - Yakguy1
> On 6/11/2012 12:20 AM, Jeff Hove wrote:
> >
> <mailto:flying(at)jeffhove.com>>
> >
> > How hard is it to modify a single-vent Yak-52 to the newer
> dual-vent system? Are instructions or a kit available?
> >
> > Jeff Hove
> >
> > On 6/10/2012 1:49 PM, A. Dennis Savarese wrote:
> >>
> <dsavarese0812(at)bellsouth.net <mailto:dsavarese0812(at)bellsouth.net>>
> >>
> >> It is my opinion the problem with the Yak 52 fuel tanks is the
> flexing of the tank metal due to vapor expansion during hot weather.
> This is prevalent in all Yak 52's with the single vent tube on the
> belly of the airplane and very rarely seen on Yak 52's with dual vent
> lines exiting the belly of the airplane. (Post 1989 manufacture).
> If the Yak 52 is left in the sun without venting the fuel tanks by
> loosening the fuel caps, the expansion of the fuel vapor causes the
> very thin fuel tank metal to expand, thus flexing the fuel tank. The
> constant flexing and contracting during hot weather ultimately causes
> the tank to fracture.
> >>
> >> Many (more than 50%) of the leaks appear around the weld points on
> the bottom of the tank where the interior baffles are welded to the
> exterior metal.
> >>
> >> I seriously doubt hard aerobatics would cause the tank to fracture
> because the tank has several baffles inside the tank which prevent
> the fuel from sloshing back and forth.
> >>
> >> I also doubt bumping on a grass field with full tanks would cause
> the metal to crack.
> >>
> >> The constant flexing of the tank metal due to a very poor tank
> vent system design is more likely the cause of the metal fracturing.
> >>
> >> Dennis
> >>
> >>
> >> A. Dennis Savarese
> >> 334-285-6263
> >> 334-546-8182 (mobile)
> >> www.yak-52.com
> >> Skype - Yakguy1
> >>
> >>
> >> On 6/10/2012 1:29 PM, Olivier Vigneron wrote:
> >>> Hi All
> >>>
> >>> I encounter some difficulty with reccurents issues about gas
> tanks that are leaking.
> >>>
> >>> An aero welder told me that are the results of hard aerobatics
> with half full tanks . As the fuel is able to hit the tank wall.
> >>>
> >>> Yesterday a lituanian mechanic told me that are the results of
> bumping on grass field with full tanks on hot days.....
> >>>
> >>>
> >>> Who's says the truth? The welder? The lituanian? both?
> >>>
> >>> This discussion is about to make an aerobatics policy to avoid
> tank cracking !
> >>>
> >>> Thanks
> >>>
> >>> Olivier
> >>> *
> >>>
> >>>
> >>> *
> >>
> >>
> >>
> >> id="misspell-19" class="mark">Photoshare, and much much
> more:http://www.matronics.com/Navigator?Yak-ListDralle
>
> *
> *
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ssssskippy
Joined: 02 May 2010
Posts: 58
|
| Posted: Mon Jun 11, 2012 12:41 pm Post subject: how not to crack your yak52 fuel tanks |
|
|
unfortunately, my yak is Lithuanian registered and Termikas don't allow this modification. They are selling their full tank wings......
For the next future, when my yak will French registered, this bladders have quite no chance to be allowed too...very sad but it's like that.
2012/6/11 A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
[quote] --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
I guess the photo did not make it.
Dennis
A. Dennis Savarese
[url=tel:334-285-6263]334-285-6263[/url]
[url=tel:334-546-8182]334-546-8182[/url] (mobile)
www.yak-52.com
Skype - Yakguy1
On 6/11/2012 2:36 PM, A. Dennis Savarese wrote:
| Quote: | --> Yak-List message posted by: "A. Dennis Savarese"
<dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Yes, we still offer the bladder tanks and they seem to do quite well.
I can't answer the question as to whether they are doing a lot of acro
or not. The primary purpose of the bladders was to increase the very
limited fuel range of the 52. We also recommend when installing the
bladders, no acro with more than the standard fuel capacity of the
original metal tanks. I do know a couple of the guys on one of the
Yak/CJ demo teams that installed the bladders. They commented that
everything was doing well.
One thing for certain, the bladders are filled with fuel proof foam
which eliminates any sloshing of the fuel. You can see this on my
web site, www.yak-52.com and click on the button at the top 'Yak 52
Fuel Bladders'.
Here's a photo of one of the bladders. You can see the blue foam
inside the oval filler plate opening.
Dennis
A. Dennis Savarese
[url=tel:334-285-6263]334-285-6263[/url]
[url=tel:334-546-8182]334-546-8182[/url] (mobile)
www.yak-52.com
Skype - Yakguy1
On 6/11/2012 1:46 PM, bill wade wrote:
| Quote: | Dennis weren't you providing bladder tanks for the Yak 52? how are
they holding up? the guys and gals that purchased doing a lot of acro?
Bill Wade
*From:* A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
*To:* yak-list(at)matronics.com (yak-list(at)matronics.com)
*Sent:* Monday, June 11, 2012 7:21 AM
*Subject:* Re: how not to crack your yak52 fuel tanks
--> Yak-List message posted by: "A. Dennis Savarese"
<dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net) <mailto:dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>>
Definitely not easy and to my knowledge, no kit is available.
Just to even think about it, the fuel tanks must have a capped off
fitting on the outboard, top end of the tanks. This is where the
second vent line is attached.
Dennis
A. Dennis Savarese
[url=tel:334-285-6263]334-285-6263[/url]
[url=tel:334-546-8182]334-546-8182[/url] (mobile)
www.yak-52.com <http://www.yak-52.com>
Skype - Yakguy1
On 6/11/2012 12:20 AM, Jeff Hove wrote:
> --> Yak-List message posted by: Jeff Hove <flying(at)jeffhove.com (flying(at)jeffhove.com)
<mailto:flying(at)jeffhove.com (flying(at)jeffhove.com)>>
>
> How hard is it to modify a single-vent Yak-52 to the newer
dual-vent system? Are instructions or a kit available?
>
> Jeff Hove
>
> On 6/10/2012 1:49 PM, A. Dennis Savarese wrote:
>> --> Yak-List message posted by: "A. Dennis Savarese"
<dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net) <mailto:dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>>
>>
>> It is my opinion the problem with the Yak 52 fuel tanks is the
flexing of the tank metal due to vapor expansion during hot weather.
This is prevalent in all Yak 52's with the single vent tube on the
belly of the airplane and very rarely seen on Yak 52's with dual vent
lines exiting the belly of the airplane. (Post 1989 manufacture).
If the Yak 52 is left in the sun without venting the fuel tanks by
loosening the fuel caps, the expansion of the fuel vapor causes the
very thin fuel tank metal to expand, thus flexing the fuel tank. The
constant flexing and contracting during hot weather ultimately causes
the tank to fracture.
>>
>> Many (more than 50%) of the leaks appear around the weld points on
the bottom of the tank where the interior baffles are welded to the
exterior metal.
>>
>> I seriously doubt hard aerobatics would cause the tank to fracture
because the tank has several baffles inside the tank which prevent
the fuel from sloshing back and forth.
>>
>> I also doubt bumping on a grass field with full tanks would cause
the metal to crack.
>>
>> The constant flexing of the tank metal due to a very poor tank
vent system design is more likely the cause of the metal fracturing.
>>
>> Dennis
>>
>>
>> A. Dennis Savarese
>> [url=tel:334-285-6263]334-285-6263[/url]
>> [url=tel:334-546-8182]334-546-8182[/url] (mobile)
>> www.yak-52.com
>> Skype - Yakguy1
>>
>>
>> On 6/10/2012 1:29 PM, Olivier Vigneron wrote:
>>> Hi All
>>>
>>> I encounter some difficulty with reccurents issues about gas
tanks that are leaking.
>>>
>>> An aero welder told me that are the results of hard aerobatics
with half full tanks . As the fuel is able to hit the tank wall.
>>>
>>> Yesterday a lituanian mechanic told me that are the results of
bumping on grass field with full tanks on hot days.....
>>>
>>>
>>> Who's says the truth? The welder? The lituanian? both?
>>>
>>> This discussion is about to make an aerobatics policy to avoid
tank cracking !
>>>
>>> Thanks
>>>
>>> Olivier
>>> *
>>>
>>>
>>> *
>>
>>
>>
>> id="misspell-19" class="mark">Photoshare, and much much
more:http://www.matronics.com/Navigator?Yak-ListDralle
*
*
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