Fabric time

Another week of work and we are making lots of progress.

Yesterday we finished the ailerons cabling, leaving the plane ready for fabric covering.

Gamal showing me how to apply anti-chafe tape

To cover a surface is not very difficult, but requires experienced hands to do a good job. Luckily we got our friend Gamal to give us a hand on it.

You start by cleaning all surfaces where you will be placing the adhesive and apply anti-chafe tape to prevent metal to cut through the fabric.

Cutting fabric

After the surface is ready you apply the fabric adhesive.  For this proyect we selected Stewert Sytems Eko-Bond adhesive mainly because it is a water based latex, so I had no problem bring it from the US on my checked in baggage.. Had customs asked about it, I was ready to say it is a new brand of hair shampoo :)

Applying the adhesive is quite easy, just "paint" a thin film of it and wait till it get sticky before placing the fabric on top.  ( a great video tutorial can be found At Stewart Systems youtube channel )

Applying the top layer of  fabric adhesive

Once the adhesive has cured, heat is applied to shrink the fabric to eliminate imperfections. Again, the process is not hard, but you need skill to do it right. I'll say it is more an art than a science. 

Water based adhesive, really nice to work with.

Gamal & Juan heat activating the sealant

Covered wing, ready for Aircraft dope

A good days work got us two wings covered and the prep work for the rest of the surfaces.

This week we should be finishing that and applying aircraft dope. With a bit of luck , the plane may be ready to test by next week.

All about cabling

Knowing how important is to properly set up the aircraft cabling, We recruited the help of our good friend Gamal Casas to help out in the process. Here in Peru, Gamal is sort of a legend among ultralight builders as he has assembled most of the flying ultralights in the region.

I've personally flew the first flight of the last Challenger ultralight he assembled, it flew hands off since the first run.

First we put together the GOAT and checked for symmetry between the wings and the fuselage.  To do this, we first installed the flaps and the ailerons with a few soft rivets to keep them in place. (We will remove those to fabric afterwards)

With that done, we measured and cut the structural cables to size, before assembling them with it's sleeves and nicos. Originally, the kit came with out any shackles. We decided to add them at on the main wings to make it easier to assemble and dis-assemble the kit for transport.  (Otherwise, it would have required the removal of bolts on the tail and nose every time)

Getting cables right is a slow and detailed process, always stopping to double check the symmetry of the structure and making sure the previous cable did not throw the alignment off.

We started with the tail section, and quickly found that  bottom cable connecting attachment was missing. I emailed Jon in NY who quickly replied with pictures of the prototype. With this Gamal was able to find a replacement from parts we had in the shop.

Tail bottom wires

Tail top wires

Wing to tail cables

Modified wing cable attachment point

The original cable attachment piece on the trailing edge of the main wing seemed to be a bit short in comparison to what we saw on the pictures, so we built a larger one to accommodate the for the flap angle.

Rear cables view

Rear cable split view

On the wing front cable attachments we added shackles for quick dis-assembly

Wing to nose cable

New rear cable attachment point with shackle for easy dis-assembly

Completed the structural cabling, we started the controls cables wiring with the pedals and rudder controls.

For this process we clamped the ailerons and tail surfaces in their middle position, then centered the pedals and the flight stick before clamping them too.

Once everything was in place, we cut and assembled the wires making sure that the control surfaces had proper travel 

Rudder controls view 2

Rudder controls

Pedals

Rudder pedals

Rudder pedals (springs located temporarily)

We paid particular attention to the ruder controls, as the ruder surface is quite large and did not wanted to allow over controlling of it.

Finally we routed the cables through the wing ribs by carefully wrapping the tense control cable with a piece of coarse sand paper (coarse side facing out of course) and sliding back and front till the tension disappeared.

Again, we put shackles on the cables so we could quickly dis-assemble the wings when needed. 

Control stick cabling

Cable routing through the ribs

Some dude posing as a pilot :) 

Weekend Update

This was a busy week!  We discovered some of the aluminum tubes where starting to build sulfate, so we decided to go ahead and zinc paint *everything*

Lots of work, one wing was pretty much done , the other had most ribs still missing, so starting Monday I had to wrap all the ribs with craft paper so the thinner wouldn't get to them. Tuesday I  painted the fuselage, the struts, the pedals.  Wednesday off, had to fly to paracas, Thursday finishing up  painting details.

Friday, a friend from Miami Fl, sent me 3 rolls of  fiberglass threaded tape (the same that came with the kit) and 3M aluminum tape. With this we where ready to assemble the rest of the ribs and get ready for 1st full assembly.

The flight club on Sunday's is usually quite busy, so we did not made a lot of work, but we managed to put the plane together with the wings finally ready. (also had an awesome meal cooked for all by our  latest student to solo. )

Tomorrow we will install the flaps and place the ailerons up with soft rivets so we can measure all control cables. (probably install the pedals and the seat too)

Finishing last details by the headlights of my truck