Today's Message Index:
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1. 12:11 AM - Re: First major mistake of my project on HS spar countersinking. Need opinions on fix! (Ken Moak)
2. 07:10 PM - Re: First major mistake of my project on HS spar (Vicki Schrimmer)
3. 07:47 PM - Re: First major mistake of my project on HS spar countersinking.Need opinions on fix! (Ralph Cloud)
4. 09:36 PM - Re: First major mistake of my project on HS spar countersinking.Need opinions on fix! (Ken Moak)
Message 1
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| Subject: | First major mistake of my project on HS spar countersinking. |
Need opinions on fix!
--> RV9-List message posted by: "Ken Moak" <airplanestuff@sbcglobal.net>
Bob
You can find the parts cost at the following links
http://www.vansaircraft.com/cgi-bin/webstore.cgi then click on "Click here
to open and view "The List""
http://www.vansaircraft.com/public/parts.txt
I have not bookmarked it, yet but probably should make it my home page ;).
I have had to use it more than I would like to admit.
HS-901 HORIZ.STAB SKIN $70.79
HS-902 HORIZ.STAB FRONT SPAR $22.42
HS-903 HORIZ.STAB REAR SPAR $22.42
HS-904 HORIZONTAL STAB RIB $10.18
HS-905 HORIZ.STAB NOSE RIB $6.79
HS-906 H STAB REAR SPAR DBLR $9.55
HS-907 H STAB FRNT SPAR DBLR $14.35
HS-910 FIBERGLASS HS TIP $25.00
HS-911-PC HORIZONTAL HINGE BRKT $3.72
HS-912-PC HORIZONTAL HINGE BRKT $3.72
Not a lot of money for the confidence of knowing it is right. Like Neil
said "It is your butt up there".
My understanding is that yes you can double it. You might want to get a
copy of the FAA, AC 43.13-1B "Acceptable Methods, Techniques and Practices -
Aircraft Inspection and Repair". It is a wealth of information, sometimes
too much. It only cost $14.00. I am taking some A&P courses and it seems
to be the primary rules, unless the aircraft manufacture specifies
otherwise.
Ken
90508 Wings
-----Original Message-----
From: owner-rv9-list-server@matronics.com
[mailto:owner-rv9-list-server@matronics.com] On Behalf Of Bob Smith
Subject: RV9-List: First major mistake of my project on HS spar
countersinking. Need opinions on fix!
--> RV9-List message posted by: "Bob Smith" <rvator@lindonnet.com>
Hi, folks! I've appreciated all the help people have given on this
list, and now I've got my first major screw-up to deal with. I'm a new
RV-9 builder working on my horizontal stabilizer, and made a mistake
countersinking the spars - I went too deep. I did not read section 5 of
the manual carefully enough and tried to countersink enough to get the
dimpled skin material to lie flush on the spar. Bad idea! Now many of
the holes are slightly enlarged. I did not discover this until I was
ready to rivet on the back spar, which appears to have been done
slightly deeper than the front spar, though both are too deep.
I talked to factory support via e-mail about this and their suggestion
was to use a 0.032 backing strip that I use to sandwich the spar from
behind. This would mean drilling out all the rivets I've put in the
front spar and putting strips in between the rib bays, and also the back
spar.
While I don't really want to start over, I'm only about 40 hours into a
1500 hour project, so that is an option I could tolerate. Do you
guys/gals think the backing strips would work OK? I'm concerned that in
drilling out all the rivets that are already in the spar that I risk
messing up the holes even more, and having to drill them out and use
larger rivets, and need a larger dimple set, etc, and basically end up
with a cobbled-together mess.
Anyway, any opinions appreciated!
Bob Smith
Message 2
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countersinking.Need opinions on fix!
| Subject: | Re: First major mistake of my project on HS spar |
countersinking.Need opinions on fix!
--> RV9-List message posted by: Vicki Schrimmer <abusymom@cox.net>
Do you guys/gals think the backing strips would work OK?
Bob Smith
Bob,
I made the same error you did and ended up buying new horizontal stabilizer
spars. At the time, I didn't know about the backing strip fix.
About a year later, I countersunk a flap spar too deep, but decided to call
the factory for help. They suggested a backing strip, so I tried it and the
flap came out great. If I had known about backing strips when I did my
horizontal stabilizer, I probably would have gone that route instead of
buying new spars.
Mark Schrimmer
Message 3
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| Subject: | First major mistake of my project on HS spar countersinking.Need |
opinions on fix!
--> RV9-List message posted by: "Ralph Cloud" <rv9ralph@flash.net>
Buy a new spar.
You are early in the project, why ad weight and compromise this early. The
spar is cheap and it will only take a week or less in shipping. I will not
take too long to get back on schedule.
The backing strip will work. However, wouldn't you feel better if you did it
right!
Ralph
Wings in Livermore, CA
do not archive
Message 4
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| Subject: | First major mistake of my project on HS spar countersinking.Need |
opinions on fix!
--> RV9-List message posted by: "Ken Moak" <airplanestuff@sbcglobal.net>
Bob,
Not being an engineer I'm not going to play one on line. That said here is
the FAA documentation I was able to locate.
AC 43.13-1B Figure 4-21 shows methods of repairing cracked leading and
trailing edges and rib intersections with a reinforcing plate under a
cracked rib or channel. This is the closest I can find to what you are
looking for. It would appear the FAA says it is an ok method of repair for
a crack (plus stop drilling) which would seem worse to me. They do specify
the material be the same allow and approx 1.5 times the thickness.
Since Van's says it is ok, I figure they have engineers to determine what an
acceptable method is. It would seem the main difference is the possible
thickness of the reinforcing plate.
I would keep a print out of Vans email in my log book. My Tech Advisor
thought I had done something incorrect with my use of blind rivets, but was
satisfied when I showed him it was an option in Van's documentation.
Good luck
Ken
-----Original Message-----
From: owner-rv9-list-server@matronics.com
[mailto:owner-rv9-list-server@matronics.com] On Behalf Of Vicki Schrimmer
Subject: Re: RV9-List: First major mistake of my project on HS spar
countersinking.Need opinions on fix!
--> RV9-List message posted by: Vicki Schrimmer <abusymom@cox.net>
Do you guys/gals think the backing strips would work OK?
Bob Smith
Bob,
I made the same error you did and ended up buying new horizontal stabilizer
spars. At the time, I didn't know about the backing strip fix.
About a year later, I countersunk a flap spar too deep, but decided to call
the factory for help. They suggested a backing strip, so I tried it and the
flap came out great. If I had known about backing strips when I did my
horizontal stabilizer, I probably would have gone that route instead of
buying new spars.
Mark Schrimmer
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