The empennage jig

I?ve gone through my construction plans and blueprints several times and haven?t found any diagrams or dimensions on how to go about building the empennage jig, but it is constantly referring to it. Maybe it?s right in front of me, and if so, if someone has a particular page number or blueprint to refer to, I?d appreciate it. I see a partial pic of it in my construction manual, and have some idea after seeing other jigs. It seems simple enough. I know most build out of 2x4?s, I think I?ll build mine out of 4x4 square metal tubes since I have plenty of that, and will lay MDF board in strips on top of that to give my cleco?s something to bite into. Also is 9? or 10? or thereabouts a good inside length to go with on the horizontal piece, or what do you recommend?

Might as well make your wing jig too

If you are going through the work of making the jig, you might as well make it wide enough for your wing as well. The jig I used was of steel 4" x 4" construction as you described. It is essentially two simple uprights with a cross beam on the bottom and a removeable cross beam about thigh high. Mine was free standing with angle iron welded to the bottom of the posts and supported with some simple bracing. Additional angle iron was welded across the post to support the wing spar. A center removeable post is added to support the HS and VS off of the center beam.

The jig should be wide enough to fit the wing inside of the posts still allowing you some clearance to reach inside the end ribs for riveting. It should not be too wide as the root end of the spar does flex. The height of the posts should be high enough to allow you to stretch a tight wire from post top to post top, centered, so you can hang a plumb line.

The center beam makes a nice flat and level place to drill your HS and VS rear spars if you put your MDF but you can do that on any flat table and move your spar to the jig when completed. I have done it both ways.

Let me sketch something and post it.

wrongway john said:

....what do you recommend?

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There's really not a whole lot to the empennage jig. I made mine out of 4X4's. Whatever material you decide to use, just make it long enough to accomodate the structure.

ok, here is a rough sketch...

JonJay said:

If you are going through the work of making the jig, you might as well make it wide enough for your wing as well. The jig I used was of steel 4" x 4" construction as you described. It is essentially two simple uprights with a cross beam on the bottom and a removeable cross beam about thigh high. Mine was free standing with angle iron welded to the bottom of the posts and supported with some simple bracing. Additional angle iron was welded across the post to support the wing spar. A center removeable post is added to support the HS and VS off of the center beam.

The jig should be wide enough to fit the wing inside of the posts still allowing you some clearance to reach inside the end ribs for riveting. It should not be too wide as the root end of the spar does flex. The height of the posts should be high enough to allow you to stretch a tight wire from post top to post top, centered, so you can hang a plumb line.

The center beam makes a nice flat and level place to drill your HS and VS rear spars if you put your MDF but you can do that on any flat table and move your spar to the jig when completed. I have done it both ways.

Let me sketch something and post it.

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Obviously, I am no artist! I agree with Rick that you can make a simple jig as he has shown, but, as you say, you have the 4x4 steel laying around, might as well make a universal jig to do the wings too. Good luck.[/IMG]

Jon Jay, thanks for taking the time to sketch that for me, and Rick for the pic as well. I think I get the gist of it. Like you guys, I want to come up with a center post as well to keep any sag out whatsoever, and will make it long enough so I can consider it for the wing as well. I?ve almost got my shop completely ready now, it's been months in the rearranging of everything, but trying to think a few steps ahead when I?m fixin? to start my empennage. No local builders to consult with, so I kind of like running this stuff through you guys first. Eventually I?ll start driving to the D/FW area and consult other builders there, but trying to save me a few trips for now.

I guess they didn?t bother with any jig drawings in my plans although they are the most recent. And I think some parts of my empennage plans are missing in section 6 ?Building the Empennage.? It keeps saying to refer to figure 6.2, 6.3, 6.4, etc. They are just not there. In section 5, they show figures of 5.1-5.9, and those were easy to find. My section 6 is only 13 pages long with an additional page of a drawing of SK 6-3, followed by a page with a few pictures front and back on it. I?m going to write Van?s and see if they left a few of these pages out. I haven?t found the figures in my blueprints either.

Thanks again for the help.

start another thread and ask for those dwgs.

I am sure someone out there has those and could get them in your hands.

Center post is for the HS and VS

wrongway john said:

Like you guys, I want to come up with a center post as well to keep any sag out whatsoever, and will make it long enough so I can consider it for the wing as well. .

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The center post on my drawing is to catch the end of the HS or VS as the jig bed is too long when you build it to accomodate the wings. You will also need to clamp or build another post to catch the center section of the HS. I did not show that. These things will be pretty intuitive when you get your skeleton ready to jig.

Build your jig as square as you can, pretty easy and stable with steel. However, the jig is only a reference. Your skeleton is what needs to be square. One could throw a jig together without care as long as it is sturdy enough to square the skeleton in it.

John,

I have the same problem with the missing figure 6.x in the RV4 plans. I'm in touch with Van's about it but they don't seem to understand exactly what I'm after. They said they would send out a new set of plans, but I suspect they will be missing the figures as well. I've spoken to another 4 builder with the same problem.

Plans refer to stuff like:
Make five brackets as shown in Fig. 6.9
Align the center of the front spar and clamp it firmly. See Fig 6.10.

Has anyone seen these mysterious figures? I think they may be photos?

Cheers
Chris.

Figures are there

The figures that are referred to are in the chapter text sections not in the plans. For Fig 6-9 and 6-10, see Chapter 6 "The Empennage" and look on pages 6-8 and 6-9.

If they're what I think they are, they're the rough sketches at the end of the section just before the photos. In the 6/6A set, plans sheets were always referred to as drawings (Drawing 12, etc.) while anything with a dot or dash referred to instructions section X, sketch or photo y (figure 6.9 should be the 9th sketch at the end of section 6).

I had same issue with the 6A plans

Vans told me that the older plan books had the sketches. They said the newer plans moved much sketch info into the plan drawings. However, that was not always the case and I asked on this board and received some sketches called for in my plan book.

WenEng said:

Vans told me that the older plan books had the sketches. They said the newer plans moved much sketch info into the plan drawings. However, that was not always the case and I asked on this board and received some sketches called for in my plan book.

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Even if it may have certain things covered in the blueprints, it?s kind of hard to know what specific part they are referencing in the construction manual. These figures go up to 6.17 in my manual, so that?s a heck of a lot of figures to be scratching our heads on. If Van?s won?t bother to send the older sketches or drawings, I?ll do what another suggested and start a new thread to see if others here may be able to help.

Originally Posted by rvator51
The figures that are referred to are in the chapter text sections not in the plans. For Fig 6-9 and 6-10, see Chapter 6 "The Empennage" and look on pages 6-8 and 6-9.

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Unfortunately, that?s not the case with these newer construction manuals. I?ve spent more hours on this trying to find it than I care to admit.

Originally Posted by beep
I have the same problem with the missing figure 6.x in the RV4 plans. I'm in touch with Van's about it but they don't seem to understand exactly what I'm after. They said they would send out a new set of plans, but I suspect they will be missing the figures as well.

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Chris, I received a new set of plans that came with my airframe kits in May of this year, and you're right, there is no difference. I wrote Van?s yesterday, and will keep you apprised of what they tell me.

wrongway john said:

I?ve gone through my construction plans and blueprints several times and haven?t found any diagrams or dimensions on how to go about building the empennage jig, but it is constantly referring to it........ what do you recommend?

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I can't imagine the sketch for the RV4 empennage jig is all that much different than the
sketch is for the RV6:

See what I mean? We have a lot of great help from the veterans here..

You can count on Rick to share his knowledge..... and sketches..

Yeah, Rick really came through for us on the empennage. Thanks Rick. That makes it more clear as to what figures they are referring too in reference to the jig, and the sketch also explains the bracket they kept referring us to as well.

I checked to see if this problem of missing figures continues through the wing and fuselage sections on the 4 construction manual, but it appears all of the figures are listed in those chapters, thank goodness. I still haven?t heard from Van?s through my e-mail, but they are generally good on getting back. Regardless, I?ll start a new thread on these missing figures and sketches in a few days since many seem to have these missing from their empennage section. If Van?s doesn?t supply us with these, maybe somebody else will help.

Doing another quick read of section six which is only 13 pages of text, I found references to figures 26 times that go up to 6.17, but not a one is in there, so it really makes it difficult to get a grasp on what they are talking about on quite a bit of this stuff. And with the sketches it says to refer to SK6-1, SK6-2, and SK6-4 some 6 different times. I didn?t see anything referring to SK6-3, but it does have that sketch listed in the back of the section for it.

A couple of days ago, Joe B. from Van?s sent me adobe files of all of the missing figures. It also has the empennage listed. For the empennage, it?s very much like the sketch that Rick showed for the RV-6, except it uses 115?-117? for the inside dimension. If anyone is missing this out of their newer construction manuals, just PM me with your e-mail, and I?ll get it right to you along with the other missing figures too if you don?t have that as well. I?ll start a new thread on that soon.

Just a quick clarification for a rookie:

True or False: The arms of the jig should not be level with each other. The main spar web is the thing that needs to be level so plumb lines fall through the matching holes in the rear spar correctly and the skeleton becomes square. ???

John

Problems with 4 x 4s

Just a note from an old woodworker....don't use 4 x 4s. They are notorious for subtile twists and not staying straight and true. Always use two 2 x 4s screwed or nailed together to create a 4 x 4. The two pieces of wood work against each other to stay way straighter!

Thanks.....