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 weather in Belgium continues to be abnormally cold for the time of year. This is a real bummer because I am using a priming booth outside that is not heated and for priming, we need at least 10 degrees C. Help I'm blocked....

Well, there's always something else to do when you build an airplane.  I don't really like that. You start doing things in many places and the questions months from now is, did I already do this or not. I prefer to stay organised and follow the plans.

But in this case, I have no choice. It's doing that or being blocked by weather.
My end of winter dip in working speed continues. 

As my tail cone has all the bulkheads clecoed on, I decided to take a shot at the J-Channels.

The J-channels are long J shaped aluminum angles that run along the length of the tail cone.

They are stiffeners. Their primary function is to prevent the skin from starting to flutter in flight and to provide some stiffness to the structure.

The stiffeners come in long stock angles that need to be cut to length. The plans clearly indicate the different lengths so this is an easy job quickly taken care of by my air cutter with 3M cutting disc.

When the ends are deburred you can continue on cutting away the ends. I found this explained pretty confusing in the manual and plans.
Well actually, it's not explained at all. The manual just says to cut away the ends and the drawing is pretty poor.
I got even more confused as I started browsing to other builder sites.
Especially when reading Bruce Swayzes' site. He cut them all parallel and then decided he did something wrong explaining a difference between left and right sides and re-orderd parts. I couldn't figure out what the hell he was talking about or doing wrong. I contacted my buddy builder Hugo to find out what he did. He told me the tabs all look similar except for the top J-channels where you don't need to take away that much material.

So that's what I did, I marked the dimensions on the ends of the J-channels with a sharpie pen and started cutting them. I used a very fine cutting disc in a dremel. The material is pretty thin so you don't need the heavy cutting disc here.

As you can see, I also marked the center location where to drill a 1/4 hole.
You do this because the bend needs to be smoothed to avoid the aluminum to crack. The right location is drilling in the middle of the bend of the J-channel.

This is how it looks on the plans 

Once cut, I clamped the J-channel in place on my tail cone assembly.

 A view from the front

 In the picture below, I drilled the 1/4inch hole where the bend will be. After that , I cut away the remaining and finishing it of with a small key file.

On one of the stiffeners, I made a bit of a mess by cutting a little to deep with the dremel and hitting in the lip. I solved it by filing a bit more away with a round keyfile until I passed the end of the crack. It looks acceptable. I assume it won't be this little lip that will keep all the plane together. The most important is that row of rivets that directly hold the stiffeners to the skin.This lip more serves as a shim between the skin and the bulkhead.

 Similar view with the dremel cut made.

 The scrap

 Finally drew a centerline on the stiffeners as per the plans.

The centerline looks like it's not really centered but believe me, it is.

The bend in the material towards the J part is counted as well in the total width.

Another small task done. Hoping on warmer weather now.

How to use

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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Legal Mumbo-Jumbo

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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