Wing doublers (4)

4 hours

I haven't touched the wings in ages, but my parents were visiting so I thought we could knock out a task that would take an extra set of hands.

There's a doubler for each wing, and I drilled all the holes back when I built the wings.  However, before they're riveted on they need to be trimmed to leave an appropriate gap along the sides of the fuselage.  The fuselage didn't exist the last time I worked on them!

Anyway, we rolled the plane into the driveway and installed the wings.  One thing I noticed was the Sonex instructions for installing the wings have you start with the right wing and insert the main pins back to front.  This works with the seat and/or floor removed, but once it's all closed up I won't have any access to the back side of the spar tunnel.  So I think for the B model we need to start with the left wing and insert the pins from the front.

We put the wings on and then started working on fitting the doublers.  I've seen a few methods online for clecoing the doubler on one row of holes over, and then making a jig to hold against the fuselage side and trace a line.  When cut to the line, theoretically the doubler will end up trimmed correctly once moved over to the correct row of holes.  I started down this path, but I realized that the row of holes closest to the fuselage and the next row over didn't seem to be exactly parallel.  Or at least the distance between rows was slightly different on the top and bottom, and forward and aft of the main spar.  I concluded it was too complicated to try and get a perfect line drawn without having the parts in their final locations.

My plan is to use the Van's wing root gasket anyway, which calls for a 3/16" gap between the edge of the wing and the fuselage.  That's a fairly big gap so it was easy enough to sneak up on it.  So what I did was cleco the doublers in place one row over, and trace an approximate line at a distance from the fuselage that I calculated would allow me to install the doublers in the right place without interfering with the fuselage.

I cut to that line, and then I was able to install both doublers in their final position.  Then it was easy to just create a jig to trace a new line exactly 3/16" away from the fuselage all the way around.  I cut to that line and that was it!

Here's what the Van's gasket looks like.  It's like a lower case 'h'.  I checked that a 3/16" gap would work and it looked about right.

Couple more pictures of the plane with the wings on before we put everything away.

It was starting to get dark by the time we were done so we called it a day and stashed everything back in the garage.  I'll rivet the doublers on later!

Cockpit Air Vents (4)

4 hours

There are a few options for getting fresh air into the cockpit.  I've seen some pretty nice Naca inlets ducted to eyeball vents, the snap-in windshield vents (which I have), and the RV-10 back seat vents.  I live in Texas at the moment, so I plan on flying in pretty hot weather.  Therefore I want all the air I can get!  I already did the windshield vents, but I've read that some lower-body cooling would be a big help.  Based on cost, complexity, and weight, I decided to install the RV-10 vents rather than Naca inlets with ducts and all the associated parts.

Vans sells all the parts needed to install these vents for about $20 a pair.  They're made for the back seats of an RV-10 which I think would have all the required holes already cut in the fuselage sides.  Even starting from scratch it was pretty simple to get these installed though.

I started by deciding where I wanted to place them.  I sat in the seat and just reached forward as far as I could without leaning forward, and made a sharpie mark on the inside of the side skin.  I figured I'd put it as far down as forward as I'd be able to reach with seatbelts on.  Then I drilled the doubler plate from the kit to the side skin, removed it, and clecoed it back on the outside so I could work from out there.

I traced the hole in the doubler on to the skin to give me an initial hole to cut out.

I cut this hole out, and then I was able to install the inner part of the door into the hole.  Then, I could trace the outer surface of the door onto the skin and enlarge the hole to match that.

Then the hole door fit in the hole with the outer surface nice and flush with the outside of the fuselage.

You can see here how the hole is now slightly larger than the doubler plate.  The door closes against the doubler and leaves it flush with the skin.

Here's the finished product:

Here's the inside:

And here's what it looks like open:

After that I repeated the whole process on the right side!

Hours Breakdown #5

Someone asked me at work how long I've spent on this thing, so here you go:

General/Misc:        16.0
Tail:                        72.0
Wings:                  147.5
Control Surfaces:   59.5
Fuselage:              196.5
Controls:                31.5
Landing Gear:        14.5
Windshield:            16.5
Canopy:                  30.0
Cockpit:                    7.0

Total:                       591 hours

Plus countless hours looking for hardware, mindlessly staring at the plans, searching the forums, and so on!

ELT Bracket (5)

5 hours

This is definitely something to take care of before riveting the aft fuselage floor in place.  In fact, for anyone reading this, an even better time to do it would be before the turtle deck is even installed!

Anyway, I will need an ELT eventually, but the plans leave you on your own for mounting it.  After a bit of research I decided I'd plan on using the ACK E-04 ELT.  However, ELT's and especially their batteries have a finite shelf life, and who knows when this plane will actually fly.  So instead of buying the whole ELT now I just bought the mounting tray that goes with it so I can figure out the mount now, and just strap the ELT to it later when it's closer to flying time.

I did what I've seen many others do, and planned to build a mount on top of the right upper longeron, behind the baggage compartment (in front of the aft seat belt mounting point).  This is a sturdy spot and still accessible for now.  I only riveted the aft floor around the access panel so far, so I was able to bend the forward half down and get a decent amount of room to work.

I started by just cutting out an arbitrarily sized piece of scrap sheet, with the angle of the aft fuselage side cut on one side of it (about 10 degrees).

Next I drilled that piece to the longeron and upper cross tie.  I added two pieces of scrap angle I had laying around as well.  This was an okay start.

 I also added a 1/8" thick strip to the top.

The mounting instructions for the ELT said it should not be able to move more than a tenth of an inch in any direction with 100 lbs of force applied.  I don't have a great way to measure that, but it seems pretty rigid.  From here I just pushed and pulled on it and examined where the mount seemed most flexible, and added reinforcements bit by bit until I couldn't really budge anything anymore.

I added two washers per screw to raise the tray up a bit, which will allow the mounting straps to clear the 1/8" thick reinforcement strip that I added to the top of my mounting sheet.

In total, what I added to the plane was 11 ounces.  Not too crazy, but I probably could have made it lighter with some less haphazard engineering I guess.

Here's what I ended up installing.

 In the plane!