VAF Forums

VAF Forums (https://vansairforce.net/community/index.php)
-   RV-12/RV-12iS (https://vansairforce.net/community/forumdisplay.php?f=73)
-   -   SB 18-02-02 Potential cracking in the horizontal stabilator front spar (https://vansairforce.net/community/showthread.php?t=157839)

joedallas 02-19-2018 03:54 PM

Yes it is a doubler
 
Scott
Yes it is a doubler
I call it a patch because you have to paint the whole stabilator if I don't want to make it look like a patch
Joe Dallas





Quote:

Originally Posted by rvbuilder2002 (Post 1240699)
Since you weren't using part numbers I assumed you were talking about the doubler (patch) that goes over cracks on the antiservo tab (a different S.B.)

The doubler on the top and bottom of the stabilator is an important component for longevity and crack avoidance.

Call it a patch if you want, but it is a doubler.... just like all of the triangular doublers that are on the exterior of the fuselage belly.


rvbuilder2002 02-19-2018 04:07 PM

Quote:

Originally Posted by joedallas (Post 1240715)
Scott
Yes it is a doubler
I call it a patch because you have to paint the whole stabilator if I don't want to make it look like a patch
Joe Dallas

I guess it does depend on the painting skills that a person has, but I just painted the doubler parts after complying with the S.B. on the RV-12iS prototype and it is not possible to tell that they weren't installed when it was originally paint (and I am far from considering myself a professional painter).

rv9builder 02-19-2018 04:19 PM

Quote:

Originally Posted by rvbuilder2002 (Post 1240657)
I am pretty sure the AST S.B. is clear in saying that the skin doubler is only required if pre-existing cracks are found at inspection. Otherwise just the change in ribs is required.

Hi Scott,

You are correct that S.B. 18-02-03 says you only need to install the HS-1226A and HS-1226B doublers if cracks are found. But since we?re taking apart the anti-servo tabs anyway to install the HS-1230 ribs, is there a good reason NOT to install the HS-1226 doublers at the same time, even if we don?t have any cracks? It seems like they would add additional resistance to cracking. But maybe there's a downside to doing this?

Thanks,

rvbuilder2002 02-19-2018 05:35 PM

Quote:

Originally Posted by rv9builder (Post 1240719)
Hi Scott,

You are correct that S.B. 18-02-03 says you only need to install the HS-1226A and HS-1226B doublers if cracks are found. But since we?re taking apart the anti-servo tabs anyway to install the HS-1230 ribs, is there a good reason NOT to install the HS-1226 doublers at the same time, even if we don?t have any cracks? It seems like they would add additional resistance to cracking. But maybe there's a downside to doing this?

Thanks,

The only down side I can think of is that sometime down the road, some one might assume there were cracks since it is installed, even if the maint. records don't indicate so.

If the new ribs get installed without any cracks present, there should be no problem with cracking in the future.

rjtjrt 02-19-2018 06:37 PM

Quote:

Originally Posted by rvbuilder2002 (Post 1240699)
.........

The doubler on the top and bottom of the stabilator is an important component for longevity and crack avoidance.

.........


Quote:

Originally Posted by rvbuilder2002 (Post 1240729)
.........

If the new ribs get installed without any cracks present, there should be no problem with cracking in the future.

I am a bit confused (not unusual).
If we find no cracks, is it desirable to install the doublers top and bottom as they are ?an important component for longevity and crack avoidance?, or is it not desirable as ?there should be no problem with cracking in the future??

skydiverlv 02-19-2018 06:39 PM

Quote:

Originally Posted by rvbuilder2002 (Post 1240717)
but I just painted the doubler parts after complying with the S.B. on the RV-12iS prototype.

Does this mean the prototype 12is is already cracked?

rvbuilder2002 02-19-2018 06:47 PM

Quote:

Originally Posted by skydiverlv (Post 1240746)
Does this mean the prototype 12is is already cracked?

Nope.


Just one of the beta tests for installing the S.B. parts.

rvbuilder2002 02-19-2018 06:49 PM

Quote:

Originally Posted by rjtjrt (Post 1240745)
I am a bit confused (not unusual).
If we find no cracks, is it desirable to install the doublers top and bottom as they are ?an important component for longevity and crack avoidance?, or is it not desirable as ?there should be no problem with cracking in the future??

You are confusing comments related to two different service bulletins.

If you read them both, it should make more sense.

rswalden 02-20-2018 06:46 PM

Quote:

Originally Posted by rvbuilder2002 (Post 1239977)
......"The option was given to delay the installation of the updated parts if no cracks are discovered, to allow owners some flexibility if they can't do the parts installation immediately because of lack of skills (weren't the aircraft's builder), haven't yet obtained the needed parts, etc........

Thanks, Scott. This makes sense and is similar to the stab spar bulletins we received a while ago for the RV-6/7/8: Inspect... If cracks found, perform the beef-up modification.

I wish this RV-12 Safety Bulletin had been more specific as to what satisfies the initial "inspection." We removed the empennage fairing today and borescoped/photographed the spar, finding no evidence of cracks on our RV-12 that had only 10 hours total airframe time. Then we flew the -12.

It would not have made sense to be required to remove and disassemble the stab and brackets for this initial inspection. The fact that the SB requires the modification to be performed at the next 100-hour/condition/annual inspection is more than cautious enough. There are probably a lot of RV-12 folks out there that might confuse the wording of the SB, thinking their airplanes are grounded until the stab is disassembled and inspected. That would strand a whole lot of airplanes!

Cudos to Van's for getting the engineering analysis completed and modification kit produced so quickly for this SB.

RFSchaller 02-20-2018 07:35 PM

About a year ago like a dummy I pushed my 12 back into the hangar without first removing my car. CRUNCH on one AST. Well at least that?s one AST with the new ribs!:D


All times are GMT -6. The time now is 04:47 AM.