Jason builds a plane

tiny rivets and more "surprises"

22/6/2018

1 Comment

 
As we get to the last of the flap repair (for this wing anyhow) I'm learning more skills that will come in handy later for my build.

So far, I've had the opportunity to work with blind "pop" rivets (the predominant style in the Zenair line of aircraft) and solid "bucked" rivets.  Both have their place and use.

Last night I started working with flush rivets.  Designed with a smooth flat top they too are bucked or squeezed to form a bond between two sheets of metal.  The advantage these have however is that they leave the top surface smooth and thereby more aerodynamic.  It also looks real cool!  Most modern metal aircraft use this style for aerodynamic reasons.  They are particularly handy around windows trim and landing gear plates where thickness tolerance of adjoining parts is important.

In the case of our flap repairs, we wanted to come up with a way to clean up the trailing edge and correct the ham-fisted attempts at a straight edge by the original builder.  Ron made up a sleeve which will be flush riveted to the trailing edge.

It starts with marking out the rivet lines and drilling small #3 holes, the size of the rivet shank:
Picture

Next, the hole is very carefully countersunk with a bit in the cordless drill:, to a depth that matches the shoulder of the rivet.  Holes for larger rivet are usually countersunk using a dimpling tool, but this tool works here:
Picture

Here is a picture of a typical flush rivet.  Note the smooth flat top, angled shoulder and round shank:
Picture

Making the hole match the rivet so it lies flush is the goal here. Too shallow and the rivet won't lie flush, too deep and it can't hold the bond adequately enough nor be completely smooth on the surface:
Picture

Work a little at a time, test fit often and eventually the rivet will sit perfectly flush with the surface... smooth!:
Picture
Once "set" with the squeezer the edges will fill in the tiny gap between the head and the countersunk hole edge.

Now repeat 30 times along the trailing edge :)
Picture

​Ron and I flipped the wing over on the bench and I removed the damaged nose skin:
Picture

I know at this point I shouldn't be surprised by anything I find with this repair, but this was interesting.  There was a "perfectly" blended rectangle, held in place by rivets and covered by the magic of cheap paint located at the back edge of the nose skin.  It is hard to make out in the picture below but I really didn't notice until I took off the skin what it actually was, so I don't have a before picture.
Picture

Once the skin rivets were removed, and the damaged nose skin removed did the curious patch reveal itself, again nothing surprises me anymore:
Picture
It isn't even attached to anything! Aerodynamic forces might be strong enough to start a tear here.... just what you want while flying!
Picture
I don't even think the underlying square backer piece is 6061 aluminum.... looks like more eaves-trough metal.

My only guess is that this was some sort of Mickey Mouse access panel to get at the wing strut mounts, but I can't for the life of me figure out how anyone thought this was an acceptable patch..... jeebus.

On a happier note, I recently confirmed my attendance this fall at the Zenith Factory open house in Mexico Missouri.  It's a two day drive from here, but most importantly William Wynne will be there demonstrating the build up of Corvair engines.  As a bonus I'll be able to take my core items for assessment and perhaps send my heads away for rebuilding at the same time.  Can't wait to atttend and learn even more!

Next up, more finishing work on the wing repair and prepping the bench for slat building.
1 Comment

airport is still an airport & 701 Flap repairs 99.9% complete

2/6/2018

1 Comment

 
Been a while since I posted, but the new job is taking up most of my days and weekends are escaping us because now the outdoor work around the house begins.  Excuses aren't welcome, but the grass doesn't stop growing.

Much earlier in this blog (my first post actually - click here) I spoke of all the work my mentor Barry Morris and I put into trying to promote and develop the South River / Sundridge Airport.  Unfortunately, Barry passed away before seeing the local municipalities get their acts together on this important community asset.

I honestly thought all was lost regarding the airport.  Three times the municipality almost sold the property to non-aviation interests who wanted to turn it into a number of non-aviation purposes.  How disheartening.... however....

I'm ecstatic to say the property was sold to a couple of business men that are enthusiastic aviation people who want to continue to develop the property PROPERLY as a municipal airport, including paving a runway and installing lighting.  "Build it and they will come...." is a quote from the 1989 "Field of Dreams".  How perfectly appropriate!

On the 12th of May, the new owners, in conjunction with COPA and the local flying club hosted a fly-in pancake breakfast.  Ron, his wife Donna and I attended and joined the fun.

Over 40 aircraft from all over southern Ontario attended, it was wonderful!  The new owner couldn't wipe the smile off his face!  There are a bunch of photos on the airport Facebook page. I was way to busy chatting with friends to take a bunch of pictures but here are a few:
Picture
Picture
A beautifully restored Navion from Muskoka! Real cool!

​Of course one of the more interesting planes that arrived was a newly kit built Zenair 750 STOL, just like I'm building.  Spoke at length with the owner who has about 80 hours on the airframe after completing it last year just south of us in Emsdale.  The biggest thing he recommended was keep at it.  There is a ton of stuff he still wants to do cosmetically (more paint, etc) but he's having way too much fun flying! He let me sit in it too and I'm even more convinced that I've made the right choice :)
Picture
Jabiru 6 cylinder powered
Picture
Vinyl 3M registration and maple leaf. I think a nice blue would look good against bare (polished?) aluminum too.
Picture
Picture
Version 3 "bubble" doors too. The visibility from the cockpit is fantastic in the 750.

The chance to see another completed 750 was a real good motivator!
​
The 701 flap repair is almost done.  Some final trimming to be done, but the skin wrapped real nice and the joining patch turned out real smooth.  Happy to be moving on to building my own flaps shortly and not fighting with other people's mistakes.
Picture
Final rivets in and correct length to match wing extension. Lessons learned here will come in real handy for my 750 flaps and the other 701 wing extension.
Picture
Extension joint. This really stiffens everything up and adds very little weight.
 
Ron has never been very happy with the pinched trailing edge design of the wings and flaps on the 701.  The original builder (as I've been saying all along) never really paid attention and the trailing edge isn't nearly straight enough.  The pinched rivets called for in the plans really add a lot of drag too.

​The plans in the 750 model I'm building wraps the skins forward to the spar, making the trailing edge much cleaner both in appearance and more importantly aerodynamically.  Every little bit helps!

To clean things up, we'll be adding a trailing edge strip and attach it with flush rivets.  Here, we're fitting the trailing edge "cover".  The first one worked real well, I'll add a picture when the one is done.
Picture

We plan on building flaps and slaps at the same time for three new 701's and my 750 and new slats for this repaired 701.  This sounds like a ton of work and it is, but there are huge time  savings because they are dimensionally the same, meaning we only have to set up jigs once.

I spent a couple of hours the other night bending my slat ribs on the forming block.  The 750 slats are identical to the 701, so I didn't need to make my own forms for this.  The only adjustment needed was one tooling hole on the tail end which is different:
Picture
Slat blanks and forming blocks
Picture
Completed slat ribs, 6 left and 6 right
 
So they turned out ok, but will need some clean up.  Not a big deal, but not a nice as I would have liked.

Next up, finish skinning the 701 wing extension.  Here is a graphic of what I have complete and ready to assemble (highlighted in blue).  Lots of stuff ready to be bent still.
Picture

​  Thanks for reading :)
1 Comment

    Author

    Husband, father and 911 dispatcher.  Long time pilot with a licence that burns a hole in my pocket where my student loan money used to be.  First time aircraft builder. Looking to fly my own airplane.

    Categories

    All
    Airframe
    Airport
    Avionics
    Decisions
    Engine
    Interior
    Keep Looking
    Mentor
    Milestone
    Mission
    Motivation
    Paperwork
    Philosophy
    Priorities
    Scrounging
    Tools
    Ultralights
    Welcome Aboard
    Workshop

    Archives

    November 2020
    October 2020
    September 2020
    August 2020
    July 2020
    June 2020
    May 2020
    April 2020
    March 2020
    February 2020
    January 2020
    December 2019
    November 2019
    September 2019
    August 2019
    June 2019
    May 2019
    April 2019
    March 2019
    February 2019
    January 2019
    December 2018
    November 2018
    October 2018
    September 2018
    August 2018
    June 2018
    April 2018
    March 2018
    February 2018
    January 2018
    December 2017
    November 2017
    October 2017
    September 2017
    August 2017
    July 2017
    June 2017
    May 2017
    April 2017
    February 2017
    January 2017
    December 2016
    October 2016
    September 2016
    August 2016
    July 2016
    June 2016
    May 2016
    April 2016
    March 2016
    February 2016
    January 2016
    December 2015
    November 2015
    October 2015
    September 2015

    RSS Feed

    build log

    Item Hours
    Engine 31
    Tail 151
    Wings 318
    Fuselage 0.5
    Interior 0
    Controls 4.5
    Avionics 5.5
    Other 64
Powered by Create your own unique website with customizable templates.