TitleGarrison

No bird ever flew nonstop from New York to Tokyo, or raced 15 miles high at triple the speed of sound.                                                                                                   
  But birds do something else.
  They do not conquer the air; they romance it.
.”

  Peter Garrison

HoursAndCounting

Jur's RV7 Aircraft Factory
2917 hours
and counting
Some decisions in life are bare of any obvious logic

 

The right wing skeleton has been completely rivetted and is back in the jig. We are also working on the left wing skeleton rivetting but since we do this is short batches of couple of ribs at a time, I decided to continue also on the next step which is matchdrilling the main skins to the skeleton of the right wing.

Time again to level the spar in the jig. This was still the case for the upper spar measurements since I didn't move anything from last time. I hang the plump bobs back to the front, middle and rear of the spar and measured for twist.

First some pictures on the spar (boring but I may want to look back them later).

 

Then came the real misery, the picture below is to give you an idea how nice if is to measure twist... Hands in the hair...

When measuring in and outboard I measured a difference of 1/32" . Being perfectionist as I am, I tried do get rid of this last 1/32" (0.79mm).

When pulling the end of the rear spar in, to shorten the gap, I noticed that actually the gap had  also increased on the other side.The structure with the skins on is so stiff that you just move the entire thing and just tilt.
At some point, I got rid of the 1/32" difference, but when measuring the top of the spar then I had 0.4° tilt already and there was a huge amount of tention to keep things in place. When releasing the clamps later, things would fold back and I would get more difficulties and possible alignment problems when rivetting.

I put everything back in it's original 0.0° and measured again. Back to 1/32". After two days of messing with this (note for later: "loosing time on the project for irrelevant details"), I decided to keep the 1/32" gap.
I started reading in the forums also and found the following (for some reason I did not find this in the manual).

- "Right now I've got it just barely to Vans' published tolerance (3/32 inch difference between inboard and outboard plumb-bob string to rear spar flange distance)."
- "When I was building my wings, I talked with Van's about that issue. On my RV-9A with 28-foot wing span, the twist was considered to be OK if under 1/8". "

So tolerance is 3/32" for an RV7 and 1/8" for an RV9, so I'm well within tolerance for now.  I hope their will be no change in this while rivetting but I doubt it.

Here are the measurements of the plumb bob in the end.

Things really look cool with those bottom skins clecoed on.

Another great shot through the lightning holes outboard 2 ribs. Notice the nice alignment of ribs and skins, they nicely butt against eachother. Good fluting job.

Then it was time to matchdrill. Nothing difficult  but time consuming. Their are over 1000 holes to drill on both sides.
I used my drill alignment tool that keeps the drill always at 90°. This surely speeds up things as you don't have to constantly bother if you are aiming perpendicular or not.
I used a sharpie pen to make markings on the vinyal as I proceeded. First the top of the middle 3 rows for 6 holes down. Then moving in and outboard for the same amount. Then moving down from the middle. Finally the top row at the spar and bottom row at the rear
spar. Finally move all clecoes down one row and drill those holes. The marking is necessary because you will sometimes doubt if you drilled a hole or not. A little trick that may help you can be seen in the picture below.

If you doubt if a hole was already drilled or not. Compare the color with the surrounding holes.In the picture, the hole right of the vertical sharpie marking has been drilled, the others not. Look at the difference in color. The drilled hole looks black, the punched (undrilled) holes look silver. The effect is even more pronounced with the led light shining on it.

After 4 hours matchdrilling spread over 2 days, the main skins of the right wing are finished... Another milestone achieved and an overall good feeling about it.

When I was finished, and looked back in to my workshop I was astonished to see the following view. The simple garage it ones was is now turned into a real airplane assembly plant.

As I had some time left, I started prepping the leading edge ribs, but that's a story for next time. Stay tuned.

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Use the kit buttons in the top ribbon bar to see a chronological overview per sub section per kit. For the full chronological article list, see chronological build link in prelude menu here below. The easiest way to lookup information is by typing in some part numbers or keywords using the search option in the ribbon bar

 

Caution !

Some advice on reading my log for fellow builders !

In some articles, I made corrections at later date on the original article to rectify my own stupidities or faults. Read through the entire article if you intend to use my findings/experiences on your own project !

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It’s possible (not likely) that I’m not as smart as I think I am. (Occasionally, I have moments when I know this to be true. Fortunately, the feeling passes quickly.) Although I have tried to make this information as accurate as I can, it is not only possible, but also quite likely, that erroneous and misguided information lurks within these pages. I cannot and do not warrant these pages to be error free and correct. Furthermore, I accept no liability for the use of this (mis)information. And, as many would say, your mileage may vary. If, after reading this, you are intent on proceeding, please be aware that the contents of this site are protected by copyright (copyright © 2011 and 2012). Nonetheless, you may copy this material subject to these two conditions: (1) any information used is for non-commercial purposes, and (2) the source of the material is properly credited. Of course, you may link to any page herein. At some articles, snippets of the plans from Vans are visible. These are for educational and illustrations purposes only and should never be used as plans for part construction or assembly as plans may have changed since the picture was taken and more important they are protected by Copyright by the Vans Aircraft Mothership company.

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