Today's Message Index:
----------------------
1. 09:04 AM - Re: Z-bracket height (again) - Help! (Don Hall)
2. 01:03 PM - Re: Z-bracket height (again) - Help! (B Tomm)
3. 05:52 PM - Re: Z-bracket height (again) - Help! (Dan Checkoway)
Message 1
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| Subject: | Re: Z-bracket height (again) - Help! |
Modifying the zbracket is crazy talk. :) Van's isn't perfect, but
they get it right more than we do.
IMO, you should not be concerned about that small of a gap just yet.
The tank skin is extremely stiff, and by the time you rivet the
structure together, it should tighten up enough to close that gap.
Even so, I offer the following suggestions for you at these stage.
- cleco every hole.
- maybe drill out the screw holes and try putting in screws.
On Mar 18, 2007, at 1:50 AM, Charlie England wrote:
> <ceengland@bellsouth.net>
>
> Michael D. Cencula wrote:
>> <matronics@cencula.com>
>> <snip>
>>> Have you tried pulling the tank down (back) on the spar with
>>> ratcheting
>>> strap clamps? (You'll need a spacer at the rear spar to keep from
>>> bending the trailing edge skin.) Run the straps directly over
>>> ribs; I
>>> think I put them one bay in from each end of the tank.
>>>
>>> With the ribs, it's easy for slight flange irregularities to add
>>> up &
>>> push the back baffle back.
>>>
>>> Have you checked to see if the back baffle is totally flat (not
>>> bowed to
>>> the rear) when it's assembled to the ribs & skin? If it's not, that
>>> would be another indicator that the flanges are pushing the
>>> baffle back.
>>>
>>> Charlie
>> Charlie,
>> Thanks for the response. Indeed I have tried pulling it down with
>> ratcheting strap clamps. I can close the gap up by doing that,
>> but doing so flexes the baffle. Is it normal to need to pull the
>> tank towards the spar before driving the screws into the platenuts?
>> With no clamps on, the baffle is mostly straight, but the center
>> is bowed *up* a little. I believe that bowing is because the
>> weight of the tank is resting on the Z bracket.
>> Mike
>
> Are the tank holes/spar holes offset by the same amount as the skin
> gap? (I've 'over-prepped' an edge or two & that could leave a gap
> at the point in question.)
>
> Is the gap between the tank skin & wing skin perfectly consistent
> along the entire length & on both top & bottom of the wing? If not:
>
> Is the spar perfectly straight? (Jack under middle of trailing edge
> spar & tweak it up/down to see if the tank will fall into place
> with a little help from the straps.)
>
> Is there any twist in the spar?
>
> If you haven't riveted on the outboard leading edge, have you tried
> the tank without the outboard leading edge in place?
>
>
Message 2
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| Subject: | Z-bracket height (again) - Help! |
If the concern is "overlap" this is not a problem. Wait until all is
riveted. I had some overlap until the center of the wing was raised to
straighten the small amount of sag. The skins were still a little close for
my liking so I used a small body file to trim a hair off. No big deal here.
Bevan
RV7A finishing kit
-----Original Message-----
From: owner-rv7-list-server@matronics.com
[mailto:owner-rv7-list-server@matronics.com] On Behalf Of Don Hall
Sent: Sunday, March 18, 2007 9:04 AM
Subject: Re: RV7-List: Z-bracket height (again) - Help!
Modifying the zbracket is crazy talk. :) Van's isn't perfect, but they get
it right more than we do.
IMO, you should not be concerned about that small of a gap just yet.
The tank skin is extremely stiff, and by the time you rivet the structure
together, it should tighten up enough to close that gap.
Even so, I offer the following suggestions for you at these stage.
- cleco every hole.
- maybe drill out the screw holes and try putting in screws.
On Mar 18, 2007, at 1:50 AM, Charlie England wrote:
> <ceengland@bellsouth.net>
>
> Michael D. Cencula wrote:
>> <matronics@cencula.com>
>> <snip>
>>> Have you tried pulling the tank down (back) on the spar with
>>> ratcheting
>>> strap clamps? (You'll need a spacer at the rear spar to keep from
>>> bending the trailing edge skin.) Run the straps directly over
>>> ribs; I
>>> think I put them one bay in from each end of the tank.
>>>
>>> With the ribs, it's easy for slight flange irregularities to add
>>> up &
>>> push the back baffle back.
>>>
>>> Have you checked to see if the back baffle is totally flat (not
>>> bowed to
>>> the rear) when it's assembled to the ribs & skin? If it's not, that
>>> would be another indicator that the flanges are pushing the
>>> baffle back.
>>>
>>> Charlie
>> Charlie,
>> Thanks for the response. Indeed I have tried pulling it down with
>> ratcheting strap clamps. I can close the gap up by doing that,
>> but doing so flexes the baffle. Is it normal to need to pull the
>> tank towards the spar before driving the screws into the platenuts?
>> With no clamps on, the baffle is mostly straight, but the center
>> is bowed *up* a little. I believe that bowing is because the
>> weight of the tank is resting on the Z bracket.
>> Mike
>
> Are the tank holes/spar holes offset by the same amount as the skin
> gap? (I've 'over-prepped' an edge or two & that could leave a gap
> at the point in question.)
>
> Is the gap between the tank skin & wing skin perfectly consistent
> along the entire length & on both top & bottom of the wing? If not:
>
> Is the spar perfectly straight? (Jack under middle of trailing edge
> spar & tweak it up/down to see if the tank will fall into place
> with a little help from the straps.)
>
> Is there any twist in the spar?
>
> If you haven't riveted on the outboard leading edge, have you tried
> the tank without the outboard leading edge in place?
>
>
Message 3
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| Subject: | Re: Z-bracket height (again) - Help! |
Check the aft flange bend angle on the fuel tank ribs. If it's not 90
degrees, then it pushes the baffle "aft" and causes the problem you're
seeing.
Also make sure the fuel tank ribs are well seated inside the tank skin.
That means all flanges on all tank ribs are square, and the "flats" around
the nose aren't causing "high spots" that prevent the nose of the rib from
seating all the way fwd.
)_( Dan
RV-7 N714D (1230 hours)
www.rvproject.com / www.weathermeister.com / www.weighmyplane.com
----- Original Message -----
From: "Don Hall" <dhall@donka.net>
Sent: Sunday, March 18, 2007 9:03 AM
Subject: Re: RV7-List: Z-bracket height (again) - Help!
>
> Modifying the zbracket is crazy talk. :) Van's isn't perfect, but they
> get it right more than we do.
>
> IMO, you should not be concerned about that small of a gap just yet. The
> tank skin is extremely stiff, and by the time you rivet the structure
> together, it should tighten up enough to close that gap.
>
> Even so, I offer the following suggestions for you at these stage.
> - cleco every hole.
> - maybe drill out the screw holes and try putting in screws.
>
>
> On Mar 18, 2007, at 1:50 AM, Charlie England wrote:
>
>> <ceengland@bellsouth.net>
>>
>> Michael D. Cencula wrote:
>>> <matronics@cencula.com>
>>> <snip>
>>>> Have you tried pulling the tank down (back) on the spar with
>>>> ratcheting
>>>> strap clamps? (You'll need a spacer at the rear spar to keep from
>>>> bending the trailing edge skin.) Run the straps directly over ribs; I
>>>> think I put them one bay in from each end of the tank.
>>>>
>>>> With the ribs, it's easy for slight flange irregularities to add up &
>>>> push the back baffle back.
>>>>
>>>> Have you checked to see if the back baffle is totally flat (not bowed
>>>> to
>>>> the rear) when it's assembled to the ribs & skin? If it's not, that
>>>> would be another indicator that the flanges are pushing the baffle
>>>> back.
>>>>
>>>> Charlie
>>> Charlie,
>>> Thanks for the response. Indeed I have tried pulling it down with
>>> ratcheting strap clamps. I can close the gap up by doing that, but
>>> doing so flexes the baffle. Is it normal to need to pull the tank
>>> towards the spar before driving the screws into the platenuts?
>>> With no clamps on, the baffle is mostly straight, but the center is
>>> bowed *up* a little. I believe that bowing is because the weight of
>>> the tank is resting on the Z bracket.
>>> Mike
>>
>> Are the tank holes/spar holes offset by the same amount as the skin gap?
>> (I've 'over-prepped' an edge or two & that could leave a gap at the
>> point in question.)
>>
>> Is the gap between the tank skin & wing skin perfectly consistent along
>> the entire length & on both top & bottom of the wing? If not:
>>
>> Is the spar perfectly straight? (Jack under middle of trailing edge spar
>> & tweak it up/down to see if the tank will fall into place with a little
>> help from the straps.)
>>
>> Is there any twist in the spar?
>>
>> If you haven't riveted on the outboard leading edge, have you tried the
>> tank without the outboard leading edge in place?
>>
>>
>>
>>
>>
>
>
>
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