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

 

After matchdrilling the armrests, I removed the side skins again and deburred the edges. Usually I don't make pictures of this, but in this case, I want to draw everyones attention on the importance of carefully deburring the notches on the F770 side skins. Especially where the conical bend has to be made. The bend at that point is very sharp at 90° and many websites and builders have reported cracks in the relief notch.

Take your time, use keyfiles and sandingpaper to smoothen notches. Here's a picture of how smooth mine was.

Same story on the notches where the rear spar bars for the wing attach.

After deburring, it was time to start forming the conical bend in the F770 ears. This is the place where the square cabin/baggage side of the fuselage transitions in the conical shape of the tail in the aft fuselage. First clamped the side skin on the bend line using the backrivet plate.

This is how I positioned the notch for the sharp bend.

I was luckyt. Hugo who's building an RV-9 still had his angle so I could just re-use it without needing to drill the angle first. I attached the piece of angle and clecoed every hole as mentioned in the manual and used a grip to start the bend. Making the bend requires a rolling motion while pressing the skin downwards to avoid making a line mark at the backrivetting plate. At the same time, push with the thumb against the inside at the sharp bend. You will need quite some force to have the 90° sharp bend but don't overstress things. Go slow, pushing it a bit at a time.

You are done when the rear end makes a nice curve and the side stands up at 90°.

Here you can see how sharp the bend actually will get on the front side. That's where most cracks occur.

If you have a crack, don't panic. stop drill at the end of the crack and use keyfiles to smoothen things out. Many builders have this.

Another look after the first matching attempt. It needed some more to be perfect.

After the second bending attempt, things fitted perfectly.

And what 's better... no cracks ! I was very pleased with this result.

Time for the other F770 skin on the passenger side

Same process of bending on the backrivet plate bend line. I actually reused the angle using the same holes and just drilling two extra ones.

Starting bending process

Me at work, with the bend near completion. I got the second one ready at the first attempt.

Passenger side installed.

And again, perfect bend, no cracks.

From the inside, after removing the baggage skins, I noticed that the tabs on F706 will need some adjusting to butt nicely against the bend skin. I will do that fine tuning in a next session.

And here is the picture with both side skins bend and installed. It's very nice to see the assembly without those ears sticking out.

Overall very pleased about this job that I was a bit scared about but that turned out to be a no-brainer in the end.

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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