16 June 2007

I had the magazine plan enlarged by 16% and a few copies made so I'd have a few to work with.

After cutting out the fuselage frames from the plan, I stuck them to the 3mm liteply and the 3mm balsa with Pritt. 

(Above) The fuse frames glued to the lite-ply.

This made it easy to cut them on the frett saw then sand them to shape on the bench sander.

Here are F4, F5, F6 all from 3mm balsa and F2 (I used lite ply rather than balsa as specified as I thought it was a bit big for balsa).

And here are the nose ring (3mm lite ply), F3 (lite ply), and the firewall from 6mm ply. 

Weights as shown:

• nosering 2g
• firewall 127g but still to have most of the middle cut away
• F2 21g
• F3 20g lightened from plan
• F4 9g
• F5 6g
• F6 2g

(Above) The cut frames..

Got the various fuse frames sorted tonight and the two fuselage sides. Glued F3 - F6 into place and added the spine. F1 and F2 are just clamped in position in the photos.

So far very happy with the build - a bit fiddly and you need at least one helper as there is no flat surface you can clamp to.

Only thing I'd do different so far is I'd use 0.8mm ply for the fuse doublers (or perhaps taper the rear ends of the doublers) to make the curve between F3 and F4 less sharp. As it is with 1.2mm ply the ply does not bend easily causing a bit of a sharp bend rather than a smooth transition (see the last picture below - it shows a top view of this). I'll probably use the dremel to grind the ply thinner to improve the bend.

Starting to think that with a Saito 91 at the front end the servos may be better off at the back.

Oh, another thing I'd change is to cut/sand the frames with a taper. The fuse sides have quite a severe taper and the frames ended up with a gap on their front between the frame and fuse side - even through the rear was tight against the side.

(Above ) The sharp ends of the ply side frame doublers.

(Above) The fuse with the frames glued to the sides..

I've always battled to butt join balsa sheet - joins not aligned, difficult to sand, masking tape gluing to the wood and pulling chunks out when removed  etc. etc.  :banghead: but I think I've found the answer :af Aliphatic glue, brown packing tape and plenty of tension! In the first picture below you can see how tightly I strap the sheets together. I actually work on a large sheet of plate glass to get it flat, the cloth is just there for the photos. Once I've strapped the sheets together as shown (about 1.5 inches apart seems to work well on 2mm sheet) I completely cover the joint with a length of tape running along it, turn it over, bend to open the joint and run a thin bead of aliphatic along the joint. Lay flat on the table, cover with something large and flat (another sheet of glass works well) and weight down. I usually use between 5 and 10Kgs for this! When dry, remove tape for a perfect join.

(Above) Balsa joining with brown packing tape.

(Above and right) The original planned tail servo location.

(Above) Is it straight? Showing how the red lines help check alignment.

(Above and right) Gluing the turtle deck into place.

Week 1

Week 2

Week 3

Week 4

Week 5