skin – PH-MNX

Bottom Center Skin

ph-mnx — Sun, 27 Oct 2019 21:51:48 +0000

This is a look from the place where the firewall will be all the way down to the tail.

The next to photo’s show the conical bend from the front side skin to the tail bottom skin.

Time: 6 Hours, Rivets: 0/0

Video

No video made.

Closing Left Wing Bottom

ph-mnx — Sun, 17 Mar 2019 20:02:21 +0000

With the right wing closed, we now know tho “trick” and can do the left wing much faster. Starting on the inboard skin, working our way to the tip.

On the inboard side of the wings are several ribs that support the “wing walk”. These ribs are so close to each other that it is hard to get your hands (with bucking bar) in there. From the trailing edge until half way you have to work from the main spar side.

After that, the lighting holes in the ribs are big enough to get your arms through and work from the inboard side.
The outboard skin of the left wing contains the pitot tube and angle of attack sensor. I look the liberty, to buy a nice pitot tube, but that requires some extra rivets to attach it.

Because the doubler plate is on the other side of the main spar web than the skin, you cannot rivet the pitot tube assembly before attaching the skin. You have to rivet it all together.

Also I added some custom stiffeners to strengthen the construction and one of the stiffeners must be attached to the rib. Maybe overkill, but the price of the pitot tube convinced me to take precautions.

The outboard skin is wider and has only one access hole, hence you have to “work” with it to rivet the tight places. As you can see here, the skin is very flexible. Of course there is a limit to it and with folding the skins in the empennage and the ailerons, you kind of get the feeling how far you can stress the aluminum.

Time: 4 Hours, Rivets: 322/0

Video

Closing Right Wing

ph-mnx — Sun, 10 Feb 2019 20:25:20 +0000

Before closing the bottom skin of the right wing, I found that the Flap brace needed to be countersunk. So we start with that, meanwhile my Dad worked on the piano-hinge of the Flaps, trimming them to the right size.

With the Flap brace countersunk and spit-primed, we started to see how to rivet the bottom skin to the wing. The plans are “clear” work in “L” shape, but it’s not clear which side the “L” should be.

At least I don’t want to bend (over-stress) the skin. First step is riveting the skin to the rear spar across the wing-walk ribs.

Checking the rivets is hard, because there is not much to see. With the flashlight I can check several of them. The rest is feeling if they are consistent.

I had to drill out five of them an reset them properly. The access holes in the bottom skin are really convenient, which makes me wonder how to do this on the outboard skin, which only has one hole and is much wider.

I have to concentrate on the inboard skin for now, because I’m clueless how to do the outboard skin. This one is already hard and it’s the easy one. Now reaching the rear spar through the access hole is hard, but I can just reach it.

Time: 5 Hours, Rivets:  207/5

Video

Left Skin Match Drill

ph-mnx — Wed, 27 Jun 2018 18:59:46 +0000

Almost identical work as the previous post, but this time the Left Wing. Clecoing the Wing Walk Doubler, the top inboard skin and top outboard skin to the Left Wing.

And start match drilling!

The top side all match drilled.

Now the bottom side, which you can recognize at the three access holes.

And when everything is done, you end with an empty spar again. Although now I read through it again and it says, let the top skin clecoed, to fit the Leading edge skin.

Time: 4 Hours, Rivets: 0/0

Video

Right Skin Match Drill

ph-mnx — Wed, 20 Jun 2018 18:54:33 +0000

After the Wing Walk Doubler, it is now time to match drill the skins (including the Wing Walk Doubler) to the Spar and Ribs. I started with the Right Wing and immediately found a problem. Hole number 18 is not in the Main Spar.

Here’s a zoom on that hole.

It’s not a misalignment, which is what I thought first. But it’s actually a hole missing in the Main Spar. Not sure if it was missing or some asymmetric design, I contacted another NVAV member (Joop), who’s also building an RV-7. Turns out his Main Spar does have this hole. Conclusion something went wrong in the Van’s factory when drilling the main spar. Oh well, with over 500 holes to match drill, I might as well drill this one too.

Nice with the Skins on there and all the Cleco’s inserted. It’s a real tight fit.

Match drilling from the mid-top down and out.

Bottom side of the Wing same thing. Here I’m fitting the access plates at the bottom of the Right Wing. They will need a little trimming, but only a very tiny bit.

Again the outer skin overlaps the inboard one.

Another 500 holes to drill.

And after 4 hours it looks like nothing happend. I guess in the end, you probably assembled and disassembled the plane four times.

Time: 4 Hours, Rivets: 0/0

Video

Horizontal Stabilizer Assembly Front

ph-mnx — Wed, 11 Oct 2017 18:52:27 +0000

Together with my dad I worked on the final assembly of the horizontal stabilizer, starting with the front spar. We accidentally riveted 1 hole that will be used in the future to secure the horizontal stabilizer to the fuselage, so we had to drill that one out again.

Now attach the front spar with the ribs to the left skin.

Riveting the skin to the front spar.

Repeat for the right skin.

With the bucking bar in the front of the horizontal stabilizer, we pushed too hard, which resulted in a minor dent.

It’s so small, I’ll fix that later, when the horizontal stabilizer assembly is finished.

We are not finished yet, the right skin and the rear spar still need to be attached.

Time: 7 Hours, Rivets: 175/1

Video

Horizontal Stabilizer Dimpling

ph-mnx — Wed, 04 Oct 2017 19:28:20 +0000

The day started with some fear, because I drilled the HS0005 and HS0006 already in the front spar which is specifically stated not to do. Now it IS stated specifically, but not very clear (jargon I still need to pick up). Also I found that it looked that there were duplicate instructions, which is apparently a clear sign that you’re not reading it right.

After fitting the left skin it turned out the HS0005 and HS0006 were in the exact right spot. So (with some luck) it turned out to be no real problem.
Next up De-burring, the most tedious part of building a plane, however at least I can sit down for a while on my new stool.

The fact that I cut my finger to one of the spars, shows that I’m not de-burring in vain. Almost the last step before priming is dimpling. Although I tested with the RV Training Project to dimple after priming, I decided to dimple first and then prime.

The DRDT-2 is expensive and I only use it for dimpling (so far), but it makes dimpling really easy. I never tried using a C-frame, but whacking something with a hammer, will probably not work for me. Besides the loud bang and strain in your arm, changes are I either miss the plunger (and dent the skin) or hit it so hard it breaks.
With this device I can hardly screw up. The most important thing is to place the skin with the right side up.

My planning was to also prime today, but I underestimated the de-burring and dimpling.

I did remove the vinyl partly on the outside, where the rivets should go. I see many builders use this method, with a soldering iron, so I’ll try it too. However I don’t see the point of doing this very precise as it is only temporary.

Time: 8 Hours

Video

Horizontal Stabilizer Fitting

ph-mnx — Sun, 01 Oct 2017 20:20:39 +0000

The assembly with the rear spar was a great fit and we could start with fitting the skin an the right horizontal stabilizer.

Aligning the pre-drilled center rib holes with the ones of the skin, required a special tool, the broom stick. We used this one also during the curving of the RV Training project.

The end result is very rewarding, however I should take more intermediate photo’s.

Today was a productive day together with my Dad and we made huge progress.

Time: 7 Hours