Back On Track

Over the Labor Day weekend I managed to cut out the broken panels, make new ones (including a layer of UNI and BID on one side), and get them glassed in place. Today I glued the three completed panels together again, which is where we were when we discovered the issue with the fractured foam in the original panels.  I used some super glue to attach a couple of sticks across the assembly to keep those panels (shaded green in the photo) from being damaged again.

Time Spent over the Holiday: 6.0 hr
Time Spent Today: 1.0 hr

Oops

When using the Fold A Plane (FAP) technique you only glass one side of certain panels until after the folding task is complete. As mentioned in an earlier post, even a light coat of epoxy, even without glass in it, is enough to prevent the panels bending in the way they need to.  One thing to note is that a properly prepared, glassed-on-one-side panel is still a fragile thing; prone to bending the wrong way and breaking. That is what has happened in the pictures. Two smallish panels, that have heavy panels on their outboard ends bent backwards and the foam snapped. One obvious issue with the break is that the panel does not bend in a smooth radius any more.

Bent this way until the foam snapped.

Now looks funny when bending.

 Nothing to do but replace the broken panels with two new glassed-on-one-side panels.

  

Time Spent Today: 1.0 hr

Getting Ready For Bending

It was an unusually cool day for August in Texas, so I spent all day on the plane. Once the last side of the last FAP panel is completed (Monday?) we will be ready to use the Hinged Panel Tool to fold the sides up on the fuselage. Before that could happen I needed to correct a mistake. We had accidentally applied epoxy, but not cloth, to an area that needs to bend, and I needed to remove that layer. Even without cloth there was no way that area of the panel was going to flex like it needed to. Ordinarily that would been sand paper and a lot of elbow grease, but I have The Machine, the 4'x8' CNC router table I built. I built it because I was originally planning on building a metal airplane and wanted to make my own 'kit' rather then using tin snips. The Machine is what I have been using to cut out my foam panels accurately.

 After aligning the panel on The Machine's bed and measuring the X and Y coordinates of the area I needed skinned, a software package I use with The Machine was only too happy to create a tool path for the router to follow. I chucked in a 3/4" mortising bit and, with my hand hovering over the emergency stop button, let The Machine skin off  the 1/25 of an inch thick layer of epoxy. It worked out perfectly.

 
I next let The Machine trim and straighten all of the sides of the 3 finished panels. Basically I had it make multiple passes along each side, each maybe 1/100" deeper than the last pass until I was happy with the resulting edge. Four passes was usually enough. Here is a before/after pair of pictures. The Machine only needed to remove 0.040" to get that edge clean and dead nuts straight.

Lastly, I mixed up some micro (epoxy and glass balloons mixed into a putty) and joined the 3 finished panels together on the HPT. The screws and fender washers are to keep the seams tight as the micro cures.

Time Spent Today: 8.0 hr

First Side of Last FAP Panel

There are four FAP panels, each with two sides. Each side must be sealed with slurry and then layered with one ply of UNI and one ply of BID. This is side number 7...  one more to go!

Time Spent Today: 4.0 hr
I realized today that I have been totaling clock hours and not man-hours, so I am making an adjustment to account for my wife's added time. All future hour reports will be man-hours.

Time Adjustment: +12.0 hours

Starboard Fuselage FAP Panel Glassed Other Side

Kinda skipped out of the groove there for a bit. WE are now in a full-on push to get the other fuselage panel done and the whole thing on the HPT and folded into a basic airplane shape.

It takes two people  about two hours to pre-cut the fiberglass cloth (one ply each of UNI & BID), seal the foam with slurry, and then position and wet out the cloth.

One picture shows the excess epoxy being squeezed out of the layup by the use of a vacuum bag.

Time Spent Today: 2.25 hr

Starboard Fuselage FAP Panel Glassed One Side

Laid on the UNI and BID on one side and then vacuum bagged it.

Time Spent Today: 1.5 hr

Back in the Saddle

Haven't done any work on the plane in almost 4 weeks.  A SCUBA diving vacation to Honduras took up 3 weeks of that; one week to prepare, eight days there, and one week to get back to normal.

Things are back to normal so today I got back to work by getting the starboard fuselage FAP panel ready to lay up, including cutting the UNI and BID to shape.

Time Spent Today: 2.0 hr