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prkaye

Well Known Member
On drawing 21, for the F-711C hor stab attach bar, they show two holes near the top that you have to measure the location of. beside two of the measurements there is an "R2" written in a circle. what does this mean?
 
See the notes in the bottom right corner of the drawing. That will be where the R2 is referenced. Revision 2.
 
Should those measurements be used to dill those holes on a tri-gear also? Where it shows "Tri-Gear Only", there are no measurements and from what I've seen on other peoples' sites, everyone seems to be placing those holes in various locations.

 
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When installing the H/S and after it is in the proper position back drill the holes in the H/S to the bars. These holes are the holes that you left blank when riveted the H/S rear spar together.
 
DOH!

Doh! i didn't see that part of the drawing, and didn't taper my 711C as shown for tri-gear!! is this going to cause interference later, i.e do i have to remove the bars and re-do the 711?
Also, i drilled those top two holes as per the measurements on the 711C drawing on the right (shown in posting above)... it didnt' say anywhere to leave these to drill later in assembly... is my 711 hosed?
 
i just looked at my plans and my HS... it looks to me like the corresponding holes in the stabilizer do not yet exist... seems that when fitting the HS we're actually supposed to back-drill the holes in the stablizer using those holes in the 711C as a guide. So it seems we are indeed supposed to drill the 711C holes first, as per the measurements on the plans... then these holes get enlarged for bolts I think.

Regarding the taper of those bars for the tri-gear... i can't see any interence issues from the plans... is this taper just a weight-savings thing, because with tri-gear we don't need to bold the tail-wheel assembly on there? (i.e. can I leave my 711C bars without the taper)?
 
Phil,

I just checked those on my RV-9A (should be same for the 7) and they need to be tapered or you stand the chance that they will interfere with the HS inboard main ribs' aft flanges. As far as the "R2", keep in mind that on these plans, the "revisions" are noted with the "R" number in a circle; you will encounter some "R" numbers with no circle around them and they refer to radius dimensions, ie, "R1" should refer to a hole or curve requiring a 1 inch radius. Hope this helps our later on...I spent 30 mins. one time scratching my head, try to figure out why there was no "R1" revision explained on the plans; it wasn't circled and referred to a radius. Hope this helps.

Regards,
 
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Thanks Mike... i just got a reply from Vans about this, and was told the taper is just for weight (although was reminded that weight counts). The taper shouldn't be required to avoid interference with the HS, because there is no taper for taildraggers (where you need the extra bulk on those bars to support the tailwheel)... I assume the HS attaches the same way for taildraggers as trigear?
 
Regarding drilling holes...Phil, why not wait to drill the holes until you install the horizontal stabilizer and have everything clamped. There's nothing to be gained by drilling these at this point.
 
Hey Phil,

The taper I was talking about is the slight taper at the tops of those bars outboard of the hole at the top. I thought that is what you were talking about. Those other tapers sure were a lot of work. I used a jigsaw with metal cutting blade and some Boelube. Took a long time. I may have skipped it if I had known it was just a weight saver. But I have been sticking with Van's weight saving options throughout the project; hope it pays off later on.

Mike
 
>> why not wait to drill the holes until you install the horizontal stabilizer and have everything clamped. There's nothing to be gained by drilling these at this point.

Because i already drilled them. The plans didn't say anything about waiting until assembly. But based on my reply from Vans, and on looking at the plans and my actual parts, I'm 99% sure the corresponding holes for these haven't yet been drilled into the HS... the HS gets match-drilled to these bars in assembly, and hten enlarged to 3/16.
 
Right, I understand that. I'm just saying that a good rule of thumb is not to drill stuff until you actually have to. This, in my opinion, is especially true on the mounting of control surfaces. Waiting on some of these gives you more options to deal with potential problems later.
 
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