Today's Message Index:
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1. 06:52 AM - Re: Z-bracket height (again) - Help! (Frank Stringham)
2. 06:44 PM - Re: Z-bracket height (again) - Help! (Charlie England)
Message 1
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| Subject: | Re: Z-bracket height (again) - Help! |
Dan and Mike
Very Interesting........................I must confess that I spent way to
much time on alignment/cutting/contemplating/rereading the plans/checking
out Web sites/realigning/drilling/riviting parts together/realigning/double
checking/had the frame dead nuts on/drilling plexie to the frame/screwed
canopy to the tip up frame/Fiberglassed the canopy to the
frame.............................WHAT>>>>>even after all that work and
aligning double checking .....left side frame of canopy is even with the
longeron............right side is another story......about mid span forward
from the roll bar it has a gradual outboard of the longeron miss alignment
of about 1/8 inch at its extreme. So even after all the WORK of aligning,
tons of duct tape it still isn't show quality. Really dums me out, but, I
know it is only a slight blemish. Look on the bright side that slight miss
alignment here on the right side will make up for what I will probably have
as a heavy left wing. So the plane will fly true, straight and level, hands
off............at least that is my story and I am sticking with it.
Mike build on and know new surprises and learning experiences a wait you but
NEVER GIVE UP!!!!!!!!!!!!!
Frank @ SGU RV7A "NDY"
"Dan Checkoway" <dan@rvproject.com>
>To: <rv7-list@matronics.com>
>Subject: Re: RV7-List: Z-bracket height (again) - Help!
>Date: Wed, 21 Mar 2007 21:24:30 -0700
>
>
>Way to go Mike. You'll have a nice straight wing, that's for sure.
>Straight = Fast ;-)
>
>I want to share a story that's kinda relevant...
>
>Two hangar doors down there's a guy with the fastest "stock" RV-4 I know
>of. His hangarmate also started building an RV-4 around the same time he
>did, but the hangarmate is still "building" -- although he hasn't touched
>it for several years. His wings are still sitting there still unfinished.
>He says he managed to inadvertently build a fair amount of twist into one
>wing, and I think that's what caused him to take a break.
>
>All that is ho-hum, but he tells an interesting story about how he built
>major twist into that wing...
>
>According to his story, he jigged the wing up dead nuts on, perfect. He
>dropped plumb bobs from the corners to confirm everything was square, but
>he didn't clamp it down right away. Apparently when he finally came back
>to clamp it, he found the wing skeleton was out of alignment. So he
>squared it up with the plumb bobs and clamped it to the jig. He drilled
>the skins to the skeleton.
>
>Later on, he (apparently) ended up discovering that a SPIDER had built a
>WEB between the plumb bob and the wing, pulling the string over to the wing
>and throwing everything off!
>
>Dunno if I buy it, but I always thought it was an interesting story. ;-)
>
>do not archive
>)_( Dan
>
>----- Original Message ----- From: "Michael D. Cencula"
><matronics@cencula.com>
>To: <rv7-list@matronics.com>
>Sent: Wednesday, March 21, 2007 8:43 PM
>Subject: Re: RV7-List: Z-bracket height (again) - Help!
>
>
>><matronics@cencula.com>
>>
>>Dan,
>>
>>That's almost exactly what I did, except I added two more of them at the
>>25%
>>and 75% spots. My blocks are 2x2 and have 2" long hex bolts threaded into
>>a
>>tee nut in the bottom end:
>>
>>http://www.our7a.com/20070320.html
>>
>>Mike
>>
>>On Wednesday March 21 2007 10:03 am, Dan Checkoway wrote:
>>>The old DWG 12A shows a "jack" supporting the center of the rear spar as
>>>the wing hangs on the stand. It says "REMOVE SAG FROM WING WITH A JACK
>>>OR
>>>EQUIVALENT SUPPORT." Lame!
>>>
>>>I really wish Van's didn't even show or mention a JACK on the drawing. To
>>>state the obvious at this point, jacks might leak down and retract over
>>>time, and there goes your perfect alignment. Given how long it takes
>>>some
>>>builders to build their wings, you really gotta consider something much
>>>more "fixed" in nature that won't vary over a period of time.
>>>
>>>Here's what I did instead:
>>>http://rvimg.com/images/2002/20020715_skeleton_on_jig.jpg
>>>
>>>It's a piece of threaded rod with a deep hole drilled into a 4x4 base
>>>block. The rod can slide in and out of the hole in the 4x4. With a nut &
>>>washer on each end of the threaded rod, I could fine tune the support
>>>height/pressure. Once it was "locked in," it wasn't going anywhere.
>>>
>>>I definitely recommend doing something like that instead of using a jack.
>>>
>>>)_( Dan
>>>RV-7 N714D (1230 hours)
>>>www.rvproject.com / www.weathermeister.com / www.weighmyplane.com
>>>
>>>----- Original Message -----
>>>From: "Bob Collins" <bcollinsrv7a@comcast.net>
>>>To: <rv7-list@matronics.com>
>>>Sent: Wednesday, March 21, 2007 6:21 AM
>>>Subject: RE: RV7-List: Z-bracket height (again) - Help!
>>>
>>><bcollinsrv7a@comcast.net>
>>> >
>>> > Boy, I'm kicking myself. Everytime I see one of these (tank gap)
>>>things > I
>>> > post that the problem is the rear spar has sagged. This time I didn't,
>>> > figuring this was already a well known fix, but I guess it's not.. It
>>> > turns
>>> > out when it happened to me, Van's had never heard of the fix before
>>>but
>>> > it's
>>> > so easy. But, boy, I can sure rememember when it made me CRAZY for a >
>>>few
>>> > hours before I gave the floor jack one and half pumps and "pop"
>>> > everything went back into place.
>>> >
>>> > I read on the RV List once where someone filed down their Z brackets
>>>to
>>> > get
>>> > it to fix. Too bad. That likely wasn't the problem and I'm unsure of
>>> > changing the Z brackets becoming a safety issue.
>>> >
>>> > Pass it on.
>>> >
>>
>>
>>
>>
>
>
_________________________________________________________________
Its tax season, make sure to follow these few simple tips
http://articles.moneycentral.msn.com/Taxes/PreparationTips/PreparationTips.aspx?icid=HMMartagline
Message 2
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| Subject: | Re: Z-bracket height (again) - Help! |
Glad it worked for you. I've worked around wood long enough to know that
it's almost never in the same place from one day to the next. I left the
alignment string stretched on my spar even after riveting started. I was
so paranoid I rechecked the level across the spar every time I started a
riveting session on the wing.
BTW, the cheap scissor jacks the come with some foreign cars work great
& are easy to adjust without tools.
Charlie
Michael D. Cencula wrote:
>
> Charlie, you rock!
>
> I dunno what the heck happened, but my wing jig was completely out of kilter.
> The wing wasn't level and it wasn't straight either. I had a post under the
> center of the rear spar to support it, but that wasn't enough to support it
> evenly. Instead of one long U shaped bow, I had two smaller ones. I ended
> up putting three supports under the rear spar at 25%, 50%, and 75% of the
> length. I also redid all the mounting points and re-leveled everything up.
>
> The only thing I can guess is that either the 4x4s I made my jig out of warped
> or twisted, or maybe my basement floor shifted some since I put the jig up
> last fall. I also discovered that the bubble in my carpenter's level shifts
> probably a full 1/32 inch just by flipping it around. Arghhh!
>
> Anyway, spending a couple evenings with a borrowed precision machinist's level
> (I'm tempted to throw out that carpenter's level I originally used) got
> everything straight, level, plumb again. And now, the skins fit together
> PERFECTLY!!!! I'm soooo happy! :-)
>
> Thanks, Charlie, and thanks everyone else who took time from their day to look
> at the problem and respond.
>
> Best regards,
>
> Mike
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