Author Archives: Michael

Time: 8 Hours

I had beautiful weather again today so I had the Hangar door open to enjoy the day while building. The first task was to get out the tools to dimple the skins of both flap skins. I had to use the DRDT, pneumatic squeezer and my close quarters rivet puller dies to get to all the holes. I didn’t take any pictures of this as you have seen them before. Before I did any riveting I decided to work on the V block jig Van’s describes. I used the boards that I used to sandwich the ailerons. I cut two of them 14″ and left one factory end on each of them so I had a square surface. I then lined them up and screwed them together. I then used one of the exterior ribs to come up with the V angles.

A couple of minutes at the bandsaw and I had 2 identical V brackets.

I then added a couple of 2×4 legs to allow me to screw them to the workbench. I just used one of the flap top skins to determine how far apart to put the brackets.

So now was the time to start riveting. I decided that I would do an item on one flap then repeat it on the other. The first task is to rivet the single hole at the aft end of the interior ribs to the rear spar that is actually the bottom skin curled up. The interesting this is that during mock up I needed 4 shims on the left flap and when I set it up after dimpling I no longer needed them as the rib was right up against the spar! Go figure.

Next was to rivet the main spar angles to the spar making sure you leave the holes that attach to the inboard rib open for later.

I then decided to work on the piano hinge attachment point. Van’s gives you two options for the pin, leave it as one length and cut it in 2 pieces removing a couple eyelets of the hinge to access them. I chose the second as it is pretty popular and makes for easy removal of the flaps. My buddy Glen gave me a photo from his build on how he did it so I just replicated his. First up was to measure out where I wanted the ends to layout which told me which 3 eyelets to remove(2 from one side and 1 from the other). It ended up being that I wanted to leave 65 eyelets from the outboard end of the hinge, removing 66-68 eyelets. I then had the area that I would need a nutplate on the spar. I drilled matching holes on the left and right spars. I used that hole and a screw to align the nutplate to drill for the 2 rivets.

I then cut 2 eyelets to make my retaining brackets(you will get the idea at the end) and drilled them together for the screw and hit both sides with the scotch-brite wheel so the were perfectly matched.

The inboard rib gets riveted to the double plate as well as the nutplate that connects the flap control arm to the flap.

Now I had all those items done on both flaps I reassembled the flaps and set the right on the shelf and put the left in the V jig I had made.

Once you have the flap tight in the jig you can remove the spar so you have access to the inside to rivet. I got one of my bucking bars and taped it all up except on on the faces so I didn’t scratch up the inside of the skins.

I took a couple of photos to see if you can see how I used this bar. For the top to bottom skin overlap the bar just rested on the rear spar and worked like a charm.

I was able to rivet all the skin overlap holes pretty easy. For the skin to ribs I ended up using my little 3/8″ thick 1.5″x1.5″ bucking bar since it’s pretty tight in this space. It took me several hours to get all these interior rivets.

On the inboard rib there are 4 rivets at the aft end on the top and bottom that are aft if the rear spar and you have no choice but to use MK319 blind rivets here.

After you get all the interior ribs done you can slide in the spar and start riveting the spar to ribs with LP4-3 blind rivets. The lower side rivets are easy to get to but the top ones require a little manipulation of the rivet stem and the top skin. I found that my cheaper rivet puller fit pretty nice.

I then moved on to the top skin to spar holes. I tried a couple of different bucking bars with different amounts of success. I ended up using my longer 1″x1″x6″ that had an angle on one end. I also tried this one too and it worked ok as well.

Those rivets went really fast as I worked down the line. You then can work on the bottom skin to spar to hinge holes.

So that was all the rivets on that flap! It was a long day but I still wanted to finish the hinge pins so I could clean the flap and call it complete. I cut the pin in half and made several measurements and took them to the vise to make some bends. One bend to follow the spar flange and one to send it to the nutplate and retaining clip I made earlier. Once I had all the bends right where I wanted them in bent the ends just a little to keep the retaining clips from falling off when removing the pins.

I was real happy with how the pins came out. I just need to do a final trim of the other ends as I left them a little long. I then took the flap out of the jig and cleaned it all up. 1 down and 1 to go, sometime this week.

Time: 9 Hours

Today started out with our weekly builder breakfast with my good buddies. I made it home by 10:30 and got hard at it working on the flaps. My work consisted of deburring every hole, finishing all edges, edge rolling and priming. It took me around 3.5 hours per flap to accomplish all those tasks. There are 6 ribs, 1 spar, 2 skins, 2 angle/plates and multiple shims. This work is the toughest and most boring on this build but it must be done and my OCD is in full effect as I want all my edges perfect. Again I only primed the mating surfaces and left the sides that will be painted unprimed. Here are a few pics of the work today but I didn’t take that many since it’s just boring.

I was able to get everything done except to dimple the skins as my back was getting sore and 9 hours is enough I think. After I finished up the first flap I took a break and went over to my buddy Glen’s house to look at his finished flaps and how his hinges turned out. I also got a chance to sit in his fuselage to see how the 8 feels, and it feels awesome!

So tomorrow is supposed to be a great day weather wise and I should get a bunch of work done if I don’t take the Harley out for a ride! 😉

Time: 8 Hours

I started today with a few errands I needed to finish before heading out into the Hangar. When I got back a set out to match drill all the holes in the right flap skins and the hinge like I did on the left flap. That went pretty fast since I had just did the left side. Before I broke down all the parts I decided to jump ahead a couple of steps and fabricate the flap support plate and angle. These two pieces beef up the inboard rib/spar area where the flap control arm will connect. First you need to cut down a couple of angles from a piece of 1.5″ x 2″ stock.

I then cut down the shorter edge to 3/4″ per the plans.

The inboard rib angles towards the inboard as it goes aft which means the plate must be bent to match so that the end that rivets to the angle I just made is square. Vans says that the angle is to be 6.3° First I clamped the piece in my bench top vise at the prescribed 25/32″ line.

I then used my digital level to establish 0°. You can see that it wasn’t perfectly 90° in the vise, probably my bench is off a little. I then zeroed it out to establish my starting point. I then clamped two boards on both sides of the plate and made a sandwich to give me some leverage and bent away. After a couple of try’s I got the angle perfect.

The end result leaves the angle square with the spar and the plate matched to the inboard rib.

I then fabricated the 4 spacers needed on the aft tips of the inboard and outboard ribs. These are needed where the bottom flap skin stops short of the aft end if the rib and the top skin wraps around and overlaps the bottoms skin.

The bottom skin curls up at the aft end to essentially create the rear spar of the flap. The aft end of the 4 inner ribs get a single rivet to attach to this rear spar. Van’s says that sometimes the rib does not touch the rear spar and you need to add spacers. I had to make 4 of them for the right flap out if .020 sheet but I didn’t need any on the left flap, go figure.

I then I larger the forward most hole in the support plate to 1/4″ and drilled the 2 holes for the platenut. This is where the flap push rod will connect.

I then put the assembled right flap on the shelf and took the left flap completely apart for deburring and edge finishing. The first thing I did was to drill the spar holes to my workbench to allow for countersinking of the bottom flange of the spar. The top flange can be dimpled but the bottom flange has the hinge on it so you want the inside edge of the spar flange flat so that the hinge sits flush. You don’t want to dimple or countersink the hinge flanges as they are too soft.

I did a little edge finishing before deciding that 8 hours was enough for today and my back is getting a little sore. I will get another good weekend worth of work over the next 2 days.

Time: 1 Hour

I got home tonight from my 2 day trip and did a few house items before going out to look at the flaps. I decided to get an hour of work in and match drill the skins on the left flap. This didn’t take too long so I decided to lay out the flap hinge and drill it to the flap. The process is to drill one side to the flap and leave the other undrilled until you install it on the wing. You make the trailing edge of the aileron and flap match. This adjustment of the position of the flap in relationship to the aileron happens on the flap hinge either moving the hinge aft or forward. From what I have read it is always aft, meaning the centerline of the hinge moves aft or away from the rear spar of the wing. What can happen is you have to move it so much you can make the holes in the wing side of the hinge get too close to the edge and impede on your edge distance for rivets. To help me with this potential problem I moved the flap side of the hinge out 1/32″ vs flush with the edge if the skin.

I then worked on drilling the hinge. These new deep reach clamps work awesome for this. I just drilled and then clecko’d as I went down the line. That’s all I did tonight as storms were approaching and I wanted to get my truck in the garage.

Time: 1 Hour

I actually had plans to get a lot done in the Hangar today but we had a pop up trip to Arkansas so that didn’t happen. I did want to get a little work done when I got home so I grabbed all the parts for the flaps and started assembling so that match drilling could begin. There are a couple other tasks ahead of this step but I wasn’t going to make a lot of noise so my neighbors don’t begin to hate me. Van says that these are the easiest control surfaces to build and I believe them as it ink took me 30 minutes to put these completely together.

I then grabbed a section of the piano hinge for the right flap and and clamped it in place with my new deep reach clecko clamps.

That’s where I stopped for tonight and will get back at it Friday and this weekend.